Pouch-type Battery Cell Comprising FPCB

Abstract

The present invention relates to a pouch-type battery cell comprising a flexible circuit board (FPCB) having circuit layers disposed on one or both sides, wherein the portion of the flexible circuit board that contacts the sealing portion where the pouch-type battery case is sealed comprises a plated portion having a plating formed on its outermost surface, and the sealing strength of the flexible circuit board with respect to the sealing portion of the pouch-type battery case can be secured due to the formation of the plating layer.

Description

Technology Field

[0001] The present invention relates to a pouch-type battery cell comprising a flexible circuit board. Specifically, it relates to a pouch-type battery cell comprising a flexible circuit board having improved sealing power in the sealing portion of the pouch-type battery cell. Background Technology

[0002] With the spread of global carbon emission regulations, lithium-ion batteries are attracting attention as an eco-friendly energy source that can replace the use of fossil fuels and drastically reduce by-products from energy use.

[0003] Lithium secondary batteries include pouch-type secondary batteries manufactured by housing an electrode assembly in a battery case made of a laminate sheet, prismatic secondary batteries manufactured by housing an electrode assembly in a battery case made of a metal material, and cylindrical secondary batteries, wherein the pouch-type secondary battery has the advantage of being easy to deform and having high energy density.

[0004] Lithium-ion batteries generate gas due to side reactions between lithium ions and the electrolyte even during normal charging and discharging processes. Since an increase in internal pressure caused by the gas generated inside the battery cell can lead to an explosion, this can affect safety.

[0005] Therefore, it is necessary to ensure safety by constantly checking the internal pressure of the battery cell.

[0006] In this regard, the pressure measuring device of Patent Document 1 includes a pressure sensing device positioned to protrude from inside to outside a pouch-type secondary battery, and a pressure transmitting device connected to the pressure sensing device to transmit pressure information to an external device.

[0007] The pressure sensing device of Patent Document 1 includes a measuring part located inside a case to measure pressure, a connecting terminal located outside the case to connect the measuring part and an external measuring instrument, and a through part located between the measuring part and the connecting terminal to be sealed together when the case is sealed.

[0008] The above penetration portion is a part that is sealed together with the case and is provided with a joint portion in which at least a portion of the insulating film has been removed to improve the sealing force of the case. The outer surface of the joint portion may be made of a material that is easy to weld or bond to the case, such as copper.

[0009] Meanwhile, recently, flexible printed circuit boards (FPCBs), composed of flexible materials capable of free shape deformation and applied as substrates for electronic products, can be used to measure internal pressure and temperature of battery cells. However, the outermost surface of these flexible printed circuit boards is generally made of polyimide or polyethylene; since these materials have low thermal fusion strength with polypropylene, the innermost layer of pouch-type battery cases, there is a problem of low sealing strength. Therefore, a technology is required to prevent a decrease in sealing strength when the flexible printed circuit board is positioned to penetrate the sealing portion of the pouch-type battery case.

[0010] Patent document 2 discloses a battery pressure sensing sensor comprising an upper electrode layer and a lower electrode layer having an electrode pattern formed thereon, an elastic layer disposed between the upper electrode layer and the lower electrode layer, and a configuration in which the battery pressure sensing sensor is disposed in a battery.

[0011] Patent Document 2 discloses only a form in which the pressure sensing sensor is disposed on the flat outer surface of the battery, but does not disclose a form in which it is disposed to penetrate the sealing portion in a pouch-type battery cell, or a technology for improving the sealing strength at this time.

[0012] Patent Document 3 relates to a battery cell pressure sensing pad disposed in contact with a battery cell, wherein the battery cell pressure sensing pad comprises a pouch body, a conduit extending from one side of the pouch body and having an internal space formed therein that communicates with the pouch body, and one end of the conduit communicates with the pouch body and a pressure sensor disposed at the other end.

[0013] Patent Document 3 discloses a technology for measuring the pressure of a battery cell, but since the pressure sensor constituting the battery cell pressure sensing pad is not configured to be mounted on the battery cell, it does not provide a technology for stably fixing the pressure sensor to the sealing part of a pouch-type battery cell.

[0014] Therefore, there is a need for a technology that not only stably secures the flexible circuit board when positioned to penetrate the sealing portion of a pouch-type battery cell, but also ensures the sealing strength of the pouch-type battery cell and enhances safety by continuously monitoring the internal pressure of the pouch-type battery cell. Prior art literature

[0015] Korean Published Patent Application No. 2021-0143603 (Nov. 29, 2021) ('Patent Document 1') Korean Published Patent Application No. 2019-0090340 (Aug. 01, 2019) ('Patent Document 2') Korean Published Patent Application No. 2021-0110921 (September 10, 2021) ('Patent Document 3') The problem to be solved

[0016] The present invention aims to solve the above-mentioned problems by providing a pouch-type battery cell comprising a flexible circuit board that can stably fix the flexible circuit board and secure the sealing strength of the pouch-type battery cell when the flexible circuit board is arranged to pass through the sealing portion of the pouch-type battery cell. means of solving the problem

[0017] The present invention for achieving such an objective comprises a pouch-type battery cell including a flexible printed circuit board (FPCB), wherein the portion of the flexible printed circuit board that contacts the sealing portion where the pouch-type battery case is sealed may include a plated portion having a plating formed on its outermost surface.

[0018] The above plating may be gold plating or nickel plating.

[0019] The thickness of the plating in the above-mentioned plating portion may be 3 μm to 6 μm.

[0020] A heat-fusion film may be added between the outer surface of the plating portion and the sealing portion.

[0021] The first end and the second end of the flexible circuit board can each be located inside and outside the pouch-type battery cell.

[0022] A pressure measuring sensor may be provided at the first end, and a connector to which an external terminal is connected may be provided at the second end.

[0023] The above pouch-type battery cell can be sealed by heat-fusing the outer periphery of a pouch-type battery case comprising an outer protective layer, a metal layer, and an inner adhesive layer.

[0024] The flexible circuit board may include a conductive layer, a base layer made of an insulating material located on one side of the conductive layer, and a cover layer for protecting the conductive layer.

[0025] The above base layer and cover layer are composed of at least one of polyethylene and polyimide, and the above internal adhesive layer may be composed of a polypropylene-based material.

[0026] The present invention provides a battery pack comprising the pouch-type battery cell as a unit battery cell.

[0027] The present invention can also be provided in a form that combines various means for solving the above problem. Effects of the invention

[0028] As explained above, the pouch-type battery cell according to the present invention includes a plating portion on the outer surface of a flexible circuit board that contacts the sealing portion of the pouch-type battery case, and when a heat-fusion film is added between the sealing portion and the plating portion to improve sealing strength, adhesion between the heat-fusion film and the flexible circuit board can be secured.

[0029] In addition, since the sealing strength between the flexible circuit board and the pouch-type battery cell is also improved, the issue of electrolyte leakage caused by poor sealing strength can be resolved. Brief explanation of the drawing

[0030] FIG. 1 is a perspective view of a pouch-type battery cell according to the present invention. Figure 2 is a vertical cross-sectional view of a flexible circuit board. Figure 3 is a cross-sectional photograph of a flexible circuit board with a plating section and a heat-fusion film attached. Figure 4 is a cross-sectional photograph of a flexible circuit board that underwent a leakage test. Figure 5 is a planar photograph of a pouch-type battery cell manufactured in a comparative example. Figure 6 is a planar photograph of a flexible circuit board that has undergone immersion testing. Specific details for implementing the invention

[0031] Embodiments that enable a person skilled in the art to easily practice the present invention are described in detail below with reference to the attached drawings. However, in describing the operating principles of preferred embodiments of the present invention in detail, if it is determined that a specific description of related known functions or configurations may unnecessarily obscure the essence of the present invention, such detailed description is omitted.

[0032] In addition, the same reference numerals are used for parts having similar functions and operations throughout the drawings. Throughout the specification, when a part is described as being connected to another part, this includes not only cases where they are directly connected, but also cases where they are indirectly connected with other elements in between. Furthermore, unless specifically stated otherwise, the inclusion of a certain component does not exclude other components but implies that additional components may be included.

[0033] Furthermore, descriptions that specify components by limiting or adding them may be applied to all inventions unless specifically limited, and are not limited to descriptions of specific inventions.

[0034] In addition, throughout the description of the invention and claims of this application, items indicated in the singular include cases where they are plural unless otherwise noted.

[0035] In addition, throughout the description of the invention and the claims of the present invention, "or" includes "and" unless otherwise noted. Therefore, "comprising A or B" means all three of the above cases: including A, including B, or including both A and B.

[0036] The present invention is described in detail with reference to the drawings and embodiments.

[0037] FIG. 1 is a perspective view of a pouch-type battery cell according to the present invention.

[0038] Referring to FIG. 1, the pouch-type battery cell (100) according to the present invention is arranged such that a flexible circuit board (210) crosses a sealing portion (120), and a plating portion (240) is added to the portion of the flexible circuit board (210) that contacts the sealing portion (120) where the pouch-type battery case (110) is sealed, with plating formed on the outermost surface.

[0039] The flexible circuit board (210) includes a conductive layer, a base layer made of an insulating material located on one side of the conductive layer, and a cover layer for protecting the conductive layer.

[0040] The conductive layer may be made of copper, which has high electrical conductivity. The base layer serves as a support for the conductive layer and simultaneously acts as an insulator to prevent current flow to areas other than the circuit direction; it may be composed of at least one of polyethylene and polyimide, which are insulating materials. The cover layer serves to cover the circuit formed on the conductive layer to protect it, and is coated with a thermosetting adhesive on the base layer; the thermosetting adhesive may be an epoxy-based adhesive.

[0041] In addition, the conductive layer, base layer, and cover layer of the above flexible circuit board may be described in the same way as the conductive layer, base layer, and cover layer constituting a conventional flexible circuit board, and their shape is not particularly limited, such as a straight shape in a planar form or a stepped shape including a fold.

[0042] The flexible circuit board may be a single-side FPCB in which a circuit layer is disposed on one side of a base layer, a double-side FPCB in which a circuit layer is disposed on both sides of a base layer, or a multi-layer FPCB in which three or more circuit layers are laminated with an insulating base layer in between.

[0043] The first end of the flexible circuit board (210) is located inside the pouch-type battery cell (100), and a pressure measuring sensor (220) is provided at the first end. The second end of the flexible circuit board (210) is located outside the pouch-type battery (100), and a connector (230) to which an external terminal is connected can be coupled to the second end.

[0044] In this way, the pouch-type battery cell (100) according to the present invention has a pressure measuring sensor (220) capable of measuring internal pressure placed inside the pouch-type battery case (100), so that the internal pressure of the pouch-type battery cell can be measured in real time. Therefore, by stopping charging before the explosion stage of the pouch-type battery cell, the explosion of the pouch-type battery cell can be prevented.

[0045] The pouch-type battery case (110) includes an outer protective layer (111), a metal layer (112), and an inner adhesive layer (113), and is sealed by heat-fusion while the outer periphery of the upper case and the lower case are overlapped.

[0046] An adhesive layer for mutual adhesion may optionally be additionally included between the outer protective layer (111) and the metal layer (112), and between the metal layer (112) and the inner adhesive layer (113).

[0047] The above-mentioned outer protective layer serves to protect the battery cell from the outside, so it has excellent resistance to the external environment and requires tensile strength and weather resistance of a certain amount or more. In this regard, the polymer resin of the outer protective layer may include polyethylene naphthalate (PEN), polyethylene terephthalate (PET), or stretched nylon, which have excellent tensile strength and weather resistance.

[0048] Aluminum (Al) or an aluminum alloy may be used so that the metal layer can perform the function of improving the formability and strength of the pouch-type battery case in addition to the function of preventing the ingress of foreign substances such as gas and moisture or the leakage of electrolyte.

[0049] The above-mentioned internal resin layer may be made of a polymer resin that has heat-fusibility, low hygroscopicity to the electrolyte, and does not expand or erode due to the electrolyte; specifically, a polypropylene-based resin may be used, and more specifically, it may be made of an unoriented polypropylene film (CPP).

[0050] In one preferred example, the pouch-type battery case according to the present invention may be structured such that the thickness of the outer protective layer is 5 μm to 40 μm, the thickness of the metal layer is 20 μm to 150 μm, and the thickness of the inner resin layer is 10 μm to 50 μm. In the pouch-type battery case, if the thickness of each layer is too thin, it is difficult to expect an improvement in barrier function against substances and strength, and conversely, if it is too thick, processability is reduced and it causes an increase in the thickness of the sheet, so it is undesirable.

[0051] The electrode assembly (101) includes a stacked electrode assembly, a jelly-roll type electrode assembly, a stacked / folded type electrode assembly, and a lamination / stacked type electrode assembly. The electrode assembly (101) is illustrated with electrode leads (102) protruding from one outer periphery, but alternatively, it may include an electrode assembly in which two electrode leads protrude in different directions.

[0052] A pouch-type battery cell (100) according to the present invention is fixed by penetrating a sealing portion (120) such that the first end and the second end of a flexible circuit board (210), which includes a pressure measuring sensor (220) and a connector (230), are respectively located on the inside and outside of a pouch-type battery case (110).

[0053] The outermost layer of the flexible circuit board (210) is generally composed of polyethylene or polyimide, but there is a problem that the electrolyte may leak because the thermal fusion adhesion with the thermal fusion film (250) composed of polypropylene resin is low.

[0054] Accordingly, the present invention discovers that the plating portion (240) plated with metal has excellent adhesion to a heat-fusion film (250) composed of a polypropylene-based resin, and by forming the plating portion (240) on the outermost surface of the flexible circuit board (210) in contact with the sealing portion (120) of the pouch-type battery case (110), the adhesion to the heat-fusion film (250) at the plating portion (240) is improved.

[0055] As such, as a plating portion for improving adhesion to a heat-sealable film, the type of plating does not need to be limited as long as it can improve adhesion to the heat-sealable film without causing chemical changes to the pouch-type battery cell, but, for example, it may be gold plating or nickel plating.

[0056] In addition, the thickness of the plating in the plating portion (240) may be 3 μm to 6 μm.

[0057] If the thickness of the plating is thinner than 3 μm, it is difficult to achieve the purpose of forming the plating part to improve adhesion with the heat-sealable film, and if it is thicker than 6 μm, it is not desirable because the sealing power of the pouch-type battery case may be reduced due to the step difference according to the thickness of the plating part.

[0058] Although the thickness of the plating portion formed on each side of the FPCB may differ, it is appropriate for the thickness of the plating portion formed on each side to be formed uniformly.

[0059] In one specific example, a heat-sealable film (250) is added between the outer surface of the plating portion (240) and the sealing portion (120) to improve the bonding strength between the flexible circuit board (210) and the pouch-type battery case (110). The heat-sealable film (250) may be made of a polypropylene-based material, which is the same material as the internal adhesive layer of the pouch-type battery case (110). By placing the heat-sealable film (250) on the outer surface of the flexible circuit board (210), the adhesion strength of the flexible circuit board (210) to the pouch-type battery case (110) can be increased. Additionally, by placing the heat-sealable film, it is possible to prevent a step difference from occurring in the pouch-type battery case due to the thickness of the flexible circuit board, thereby preventing a decrease in the sealing strength of the pouch-type battery case.

[0060] A sensor utilizing piezoresistive technology may be used as a pressure measuring sensor (220). Specifically, a pressure measuring sensor is located at the bottom of the housing, and a potting gel is contained above the pressure measuring sensor, and the pressure measuring sensor can measure the pressure exerted by the gas pressure entering through an opening in the housing to pressurize the potting gel.

[0061] The pressure measuring sensor (220) can be designed with a Wheatstone bridge structure to convert the pressure applied to the potting gel into an electrical signal.

[0062] A pressure measuring sensor (220) placed within a pouch-type battery cell (100) can be placed at a position adjacent to an electrode lead (102) protruding from an electrode assembly (101).

[0063] The two side portions of the electrode lead are treated as dead space inside the pouch-type battery case (110), and even if a pressure measuring sensor (220) is placed as in Fig. 1, there is an advantage that the exterior of the pouch-type battery cell is not deformed or the overall volume does not increase.

[0064] Additionally, since the pressure measuring sensor (220) is intended to measure the pressure inside the pouch-type battery cell (100), it is preferable to place it at a location adjacent to the electrode lead (102), which is treated as a dead space inside the pouch-type battery case (110), or next to the electrode tab-electrode lead connection part, so that the pressure resulting from the expansion of the electrode assembly (101) does not affect the pressure measuring sensor.

[0065] Figure 2 is a vertical cross-sectional view of a flexible circuit board.

[0066] Referring to FIG. 2, two types of flexible circuit boards are illustrated, each having a connector (230) and a pressure measuring sensor (220) attached to each of the two ends.

[0067] (a) A flexible circuit board (210) has a base layer (211) attached to both sides of a conductive layer (212) that forms a circuit. The base layer (211) may be made of polyethylene or polyimide material, but since these materials have low adhesion to the internal adhesive layer of a pouch-type battery case, if the flexible circuit board is placed in the sealing part of the pouch-type battery case and sealed, leakage of the electrolyte may be a problem.

[0068] Accordingly, the sealing power can be improved by forming a plating portion (240) on the outer surface of the base layer (211) in the portion disposed in the sealing portion of the pouch-type battery case. Additionally, the sealing power between the plating portion (240) and the pouch-type battery case can be further improved by additionally attaching a heat-sealable film to the surface of the plating portion (240).

[0069] (b) The flexible circuit board (210) is illustrated in the form of a double-sided FPCB in which a conductive layer (212) with a circuit drawn on it is bonded to both sides of a base layer (211), and a cover layer (213) is added to surround the conductive layer (212). However, in the present invention, the flexible circuit board may include a single-sided FPCB and a multi-layer FPCB.

[0070] A connector (230) for electrical connection with an external terminal is attached to the left side of the flexible circuit boards (210), and a pressure measuring sensor (220) is attached to the right side. The pressure measuring sensor (220) can measure the internal pressure of a pouch-type battery cell and transmit pressure information to an external device via a communication method.

[0071] (b) In the flexible circuit board (210), the portion of the outer surface of the base layer (211) where the conductive layer (212) and the cover layer (213) are not formed forms the outermost surface of the base layer (211). Since the base layer (211), made of polyethylene or polyimide material, has a problem of low adhesion to the internal adhesive layer of the pouch-type battery case, to overcome this, a plating portion (240) is formed on the portion of the outer surface of the base layer (211) that is located in the sealing portion of the pouch-type battery case. In addition, a heat-sealable film can be additionally attached to the surface of the plating portion (240) to further improve the sealing force between the plating portion (240) and the pouch-type battery case.

[0072] Alternatively, if the portion located in the sealing part of the pouch-type battery case is the conductive layer (212) and the cover layer (213), a plating portion (240) may be formed on the cover layer (213), or the cover layer (213) may be removed to expose the conductive layer (212). In this case, since the conductive layer (212) has excellent adhesion to the internal adhesive layer or heat-sealable film of the pouch-type battery case, a plating portion may not be formed.

[0073] (a) The plating thickness of the plating portion (240) on the flexible circuit board (210) may be 3 μm to 6 μm, and within the above range, the thickness of the plating portion on the upper surface and the thickness of the plating portion on the lower surface may be formed differently from each other, but each plating portion may be formed with a uniform thickness.

[0074] (b) Although the plating thickness of the plating portion (240) in the flexible circuit board (210) is illustrated to correspond to the maximum thickness of the cover layer (213) added to the conductive layer (212), considering that only the plating portion (240) is placed in the sealing portion of the pouch-type battery case, the thickness of the plating portion (240) can be formed regardless of the thickness of the conductive layer and the cover layer, and can be formed thinner than the maximum thickness of the cover layer (213) added to the conductive layer (212).

[0075] Considering that a flexible circuit board (210) is placed between the upper case and the lower case of a pouch-type battery case, both contact surfaces where the flexible circuit board (210) and the pouch-type battery case come into contact require an effect that enhances adhesion. Accordingly, the plating portion (240) can be formed on the upper and lower surfaces of the base portion (211), respectively.

[0076] In this way, the present invention can improve adhesion to the sealing portion of a pouch-type battery case by forming a plating portion on the outer surface of the base layer of a flexible circuit board, specifically on the portion positioned at the sealing portion of the pouch-type battery case. Additionally, by placing a heat-sealable film between the plating portion of the flexible circuit board and the pouch-type battery case, the adhesion between the flexible circuit board and the pouch-type battery case can be further enhanced, thereby preventing problems such as electrolyte leakage.

[0077] The following description refers to embodiments of the present invention, but this is for the sake of easier understanding of the present invention and does not limit the scope of the present invention.

[0078] <Example>

[0079] To verify the adhesion between the flexible circuit board and the pouch-type battery case, a heat-sealable film composed of the same material as the internal resin layer of the pouch-type battery case and a flexible circuit board were prepared.

[0080] Nickel plating was performed on a part of the flexible circuit board to form plated sections on both sides of the flexible circuit board.

[0081] In order to attach a heat-fusion film to the outer surface of the above-mentioned plating part, a flexible circuit board with a plating part formed thereon and a heat-fusion film were placed on a pressure jig and heated and pressed at a temperature of 160°C or higher.

[0082] <Comparative Example>

[0083] A pouch-type battery cell was manufactured by mounting a flexible circuit board without a plating layer into a pouch-type battery case without applying a heat-fusion film, and then heat-fusing it.

[0084] <Experimental Example 1> Visual inspection

[0085] A flexible circuit board with a heat-fusion film attached to the plated portion, manufactured in the above example, was prepared and an external inspection was performed, and Figure 3 shows a cross-sectional photograph of the flexible circuit board with the heat-fusion film attached to the plated portion.

[0086] Referring to FIG. 3, the upper section shows the left cross-section and the lower section shows the right cross-section, and it can be seen that the heat-fusion film (250) is attached so as to be in close contact with the entire outer surface of the plating section (240).

[0087] Considering that the heat-sealable film and the internal resin layer of the pouch-type battery case are composed of the same material, it can be expected that excellent adhesion can be secured even when a flexible circuit board with a plated portion is interposed in the sealing portion of the pouch-type battery case and heat-sealed.

[0088] <Experimental Example 2> Leakage test

[0089] In the above example, a flexible circuit board with a heat-sealable film attached to the plating portion was cut, and a penetrating liquid was injected for 5 minutes. After wiping off the penetrating liquid adhering to the outer surface, the cross-section was examined under a microscope.

[0090] Figure 4 is a cross-sectional photograph of a flexible circuit board that underwent a leakage test.

[0091] Referring to FIG. 4, the upper section shows the left cross-section and the lower section shows the right cross-section. It can be seen that the penetrating liquid has not penetrated into the plating section (240) and the heat-fusion film (250), and thus the adhesive state between the plating section (240) and the heat-fusion film (250) is stably maintained.

[0092] Figure 5 is a planar photograph of a pouch-type battery cell manufactured in a comparative example.

[0093] Referring to Fig. 5, since the flexible circuit board has no plating formed and the heat-sealed film is not adhered, it can be confirmed that the electrolyte leaked from the sealing portion of the pouch-type battery cell through which the flexible circuit board penetrates.

[0094] Since the polyethylene or polyimide used on the outermost surface of the flexible circuit board has low adhesion to the internal adhesive layer of the pouch-type battery case, which is mainly composed of polypropylene, the pouch-type battery case is not sealed at the parts where the flexible circuit board penetrates.

[0095] Therefore, there is a problem where not only electrolyte leakage but also external substances can enter the pouch-type battery cell.

[0096] <Experimental Example 3> Immersion test

[0097] A pouch containing 1,000 ppm of moisture and an electrolyte was prepared. A flexible circuit board with a heat-sealable film attached to the plated portion, manufactured in the above example, was placed in the pouch and stored at 80°C for 24 hours, and then left at room temperature for 1 hour.

[0098] We checked whether the flexible circuit board and the heat-sealed film attached to the flexible circuit board separated by holding them by hand and pulling them in opposite directions.

[0099] Figure 6 is a planar photograph of a flexible circuit board that has undergone immersion testing.

[0100] Referring to FIG. 6, it can be seen that the heat-fused film (250) is stretched and deformed into an uneven shape due to tension pulling in opposite directions, but the heat-fused film (250) remains attached to the flexible circuit board (210) without being separated.

[0101] In this way, by plating the flexible circuit board with gold or nickel, the adhesion between the pouch-type case and the flexible circuit board can be improved.

[0102] A person skilled in the art to which the present invention pertains would be able to perform various applications and modifications within the scope of the present invention based on the above content. Explanation of the symbols

[0103] 100: Pouch-type battery cell 101: Electrode assembly 102: Electrode lead 110: Pouch-type battery case 111: External protection layer 112: Metal layer 113: Internal adhesive layer 120: Sealing part 210: Flexible circuit board 211: Base layer 212: Evangelism layer 213: Cover layer 220: Pressure measurement sensor 230: Connector 240: Plating part 250: Heat-sealed film

Claims

Claim 1 A pouch-type battery cell comprising a flexible printed circuit board (FPCB), wherein the portion of the flexible printed circuit board that contacts the sealing portion where the pouch-type battery case is sealed includes a plated portion having a plating formed on its outermost surface, and a heat-sealable film is added between the outer surface of the plated portion and the sealing portion. Claim 2 In claim 1, the plating is gold plating or nickel plating, a pouch-type battery cell. Claim 3 A pouch-type battery cell according to claim 1, wherein the thickness of the plating in the plating portion is 3 μm to 6 μm. Claim 4 delete Claim 5 In claim 1, the first end and the second end of the flexible circuit board are each located inside and outside the pouch-type battery cell. Claim 6 In claim 5, a pouch-type battery cell having a pressure measuring sensor at the first end and a connector to which an external terminal is connected at the second end. Claim 7 In claim 1, the pouch-type battery cell is a pouch-type battery cell that is sealed by heat-fusing the outer periphery of a pouch-type battery case comprising an outer protective layer, a metal layer, and an inner adhesive layer. Claim 8 In claim 1, the flexible circuit board comprises a pouch-type battery cell including a conductive layer, a base layer made of an insulating material located on one side of the conductive layer, and a cover layer for protecting the conductive layer. Claim 9 A pouch-type battery cell according to claim 7, wherein the base layer and the cover layer are composed of at least one of polyethylene and polyimide, and the internal adhesive layer is composed of a polypropylene-based material. Claim 10 A battery pack comprising a pouch-type battery cell according to any one of paragraphs 1 to 3 and paragraphs 5 to 9 as a unit battery cell.

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