Flexible printed circuit board and secondary battery module including same

Abstract

The present invention provides a flexible printed circuit board and a secondary battery module that can detect and continuously monitor water ingress into a secondary battery module and electrolyte leakage from pouch cells therein, ensure battery quality and safety, and maximize space utilization and energy density within the module. The secondary battery module of the present invention includes a pouch cell assembly in which a plurality of pouch cells are arranged in a thickness direction, a bus bar frame assembly coupled to one and other sides of the pouch cell assembly, and a flexible printed circuit board coupled to the bus bar frame assembly and having a film layer laminated on a metal layer, the flexible printed circuit board including a body portion provided between the bus bar frame assembly and a sensing portion extending from the body portion, extending from one and other sides in a length direction of the body portion, and provided on one and other sides in a width direction of the body portion, for sensing the presence or absence of leakage of water or electrolyte.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0024705 filed on February 24, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a flexible printed circuit board and a secondary battery module including the same, and relates to a flexible printed circuit board and a secondary battery module including the same, which can detect and continuously monitor whether the secondary battery module has been submerged in water or whether electrolyte of a pouch cell has leaked within the secondary battery module. [Background technology]

[0003] A secondary battery is a battery that can be charged and discharged, unlike a primary battery that cannot be charged, and types of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, lithium-ion polymer batteries, etc. These secondary batteries are used not only in small products such as digital cameras, notebook computers, mobile phones, PDAs, and e-bikes, but also in large products that require high output, such as electric vehicles and hybrid vehicles, and in power storage devices and backup power storage devices that store surplus generated power and new renewable energy.

[0004] These secondary batteries are classified into pouch type, can type, etc. depending on the material of the battery case that houses the electrode assembly. The pouch type houses the electrode assembly in a pouch made of an irregular flexible polymer material, while the can type houses the electrode assembly in a case made of a regular metal or plastic material.

[0005] The secondary battery may be configured as a cell, a module, or a pack depending on the unit of assembly of the secondary battery. First, a cell is a basic unit of a secondary battery that can charge and discharge electrical energy, and may be the above-mentioned pouch-type or can-type secondary battery.

[0006] FIG. 1 is a perspective view showing a conventional secondary battery module. FIG. 2 is a perspective view showing a main configuration of a conventional secondary battery module. Referring to FIGS. 1 and 2, a module 1 refers to a unit assembly in which a predetermined number of cells are grouped together or a predetermined number of cell assemblies 2 are formed and housed in a frame to protect the cells from external impact, heat, vibration, etc., as shown in FIG. 1. In particular, the module may include not only the cell assemblies 2, but also a fixing plate 3 (or a bus bar frame assembly) to which a bus bar for electrically connecting the cell assemblies is attached and which fixes the pouch cell assembly, a circuit board 4 for measuring the voltage, temperature, etc. of the cells within the module and transmitting the results to the outside, etc.

[0007] The pack is the final form of the battery system, and is completed by mounting various control and protection systems, such as a BMS and a cooling system, on a secondary battery module.

[0008] On the other hand, in the case of pouch-type cells, electrolyte injected into the inside of the cell may leak inside the module due to poor sealing of the pouch or damage to the pouch. In that case, corrosion of the pouch may occur, which may lead to a decrease in battery performance or a fire in the vehicle, thereby reducing the quality and reliability of the product and seriously threatening the safety of users.

[0009] Therefore, during the manufacturing process, it is necessary to check whether the electrolyte of the cells has leaked within the completed assembled module, and even after the module or pack is installed in a vehicle, continuous monitoring is required in the field to ensure safety. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made to solve the above problems, and an object of the present invention is to provide a flexible printed circuit board and a secondary battery module including the same, which can detect and continuously monitor whether a secondary battery module is flooded with water or whether an electrolyte of a pouch cell in the secondary battery module has leaked with a simple structural change, thereby ensuring the quality and safety of the battery and maximizing the space utilization and energy density inside the module. [Means for solving the problem]

[0011] The secondary battery module according to the first embodiment of the present invention includes a pouch cell assembly formed by arranging a plurality of pouch cells in a thickness direction, a bus bar frame assembly respectively coupled to one side and the other side of the pouch cell assembly, and a flexible printed circuit (FPC) coupled to the bus bar frame assembly and having a film layer laminated on at least one side of a metal layer, the flexible printed circuit including: a body portion provided between the bus bar frame assemblies respectively coupled to one side and the other side of the pouch cell assembly; and a sensing portion extending from the body portion, extending from at least one of one side and the other side of the length direction basis of the body portion and provided on one side and the other side of the width direction basis of the body portion, for sensing the presence or absence of leakage of moisture or electrolyte.

[0012] The sensing portion may include a first extension line portion extending toward one side of a width direction reference of the body portion, and a second extension line portion extending toward the other side of the width direction reference of the body portion.

[0013] The first extension line portion and the second extension line portion may be bent along a periphery of the bus bar frame assembly.

[0014] The first and second extension line portions may be bent such that their respective ends face each other with a predetermined distance between them.

[0015] The first extension line portion may include a first exposed portion at an end portion where the metal layer is exposed, and the second extension line portion may include a second exposed portion at an end portion where the metal layer is exposed.

[0016] The sensing unit may sense whether or not the first exposed portion and the second exposed portion are electrically connected by moisture or an electrolyte.

[0017] The bus bar frame assembly may include a bus bar electrically connected to the electrode lead of the pouch assembly, a lead insertion portion having a slit formed therein that penetrates front and rear surfaces so that the electrode lead can be inserted therein, a bus bar mounting portion formed on one side of the lead insertion portion, and a fixing plate having a terrace portion formed thereon that extends from a lower portion of the lead insertion portion toward the pouch cell assembly, and the first exposed portion and the second exposed portion may be placed on an upper surface of the terrace portion.

[0018] The bus bar frame assembly may further include a cover plate that covers the bus bars and is coupled to the fixed plate.

[0019] The secondary battery module may further include a module case having both ends open and housing the pouch cell assemblies and the bus bar frame assembly therein, and end plates covering the open ends of the module case.

[0020] The secondary battery module may further include a connector that transmits a signal output from the flexible printed circuit board to an external battery management system (BMS).

[0021] The terrace portion of the secondary battery module according to embodiment 2 of the present invention may include a first inclined portion whose height decreases from one side to the center, and a second inclined portion whose height decreases from the other side to the center, and the first exposed portion may be placed on an upper surface of the first inclined portion, and the second exposed portion may be placed on an upper surface of the second inclined portion.

[0022] A flexible printed circuit board according to a second embodiment of the present invention is a flexible printed circuit board (FPC) having a film layer laminated on at least one side of a metal layer, and includes a body portion and a sensing portion extending from the body portion and provided from at least one of one and the other sides of a length direction reference of the body portion to one and the other sides of a width direction reference of the body portion, for sensing the presence or absence of leakage of moisture or electrolyte.

[0023] The sensing portion may include a first extension line portion extending toward one side of a width direction reference of the body portion, and a second extension line portion extending toward the other side of the width direction reference of the body portion.

[0024] The first extension line portion may extend toward one side of a width direction reference of the main body portion and be formed parallel to the length direction of the main body portion in at least a portion of the region including the end portion, and the second extension line portion may extend toward the other side of a width direction reference of the main body portion and be formed parallel to the length direction of the main body portion in at least a portion of the region including the end portion.

[0025] The first extension line portion and the second extension line portion may be formed to be bendable.

[0026] The first extension line portion may include a first exposed portion at an end portion where the metal layer is exposed, and the second extension line portion may include a second exposed portion at an end portion where the metal layer is exposed.

[0027] The sensing unit may sense whether or not the first exposed portion and the second exposed portion are electrically connected by moisture or an electrolyte. Effect of the Invention

[0028] The secondary battery module according to the present invention includes a pouch cell assembly formed by arranging a plurality of pouch cells in a thickness direction, a bus bar frame assembly coupled to one side and the other side of the pouch cell assembly, and a flexible printed circuit (FPC) coupled to the bus bar frame assembly and having a film layer laminated on at least one side of a metal layer, the flexible printed circuit including a body portion provided between the bus bar frame assemblies coupled to one side and the other side of the pouch cell assembly, and a sensing unit extending from the body portion and extending from at least one of one side and the other side of the body portion in a length direction and provided on one side and the other side of the body portion in a width direction, the sensing unit detecting whether or not moisture or electrolyte leakage occurs. With such a simple structural change, it is possible to detect and continuously monitor whether or not the secondary battery module is flooded with water or whether or not electrolyte leakage from the pouch cells in the secondary battery module occurs, thereby ensuring the quality and safety of the battery and maximizing the space utilization rate and energy density inside the module. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a perspective view showing a conventional secondary battery module. [Diagram 2] FIG. 1 is a perspective view showing a main configuration of a conventional secondary battery module. [Diagram 3] FIG. 2 is an exploded perspective view showing the secondary battery module according to the first embodiment of the present invention. [Figure 4] 1 is a perspective view showing a main configuration of a secondary battery module according to a first embodiment of the present invention. [Diagram 5] 1 is a perspective view showing a flexible printed circuit board, a fixing plate, and a connector of a secondary battery module according to a first embodiment of the present invention. [Figure 6a] 6 is a side view showing a state in which region A in FIG. 5 is viewed from the side. [Figure 6b] 6 is a plan view showing a state in which area A in FIG. 5 is viewed from above. [Figure 7]FIG. 11 is a perspective view showing a fixing plate of a secondary battery module according to a second embodiment of the present invention. [Figure 8a] 11 is a side view showing a first extension line portion, a second extension line portion, and a terrace portion of a secondary battery module according to a second embodiment of the present invention, as viewed from the side. FIG. [Figure 8b] 11 is a plan view showing a first extension line portion, a second extension line portion, and a terrace portion of a secondary battery module according to a second embodiment of the present invention, viewed from above. FIG. [Figure 9a] FIG. 11 is a perspective view showing a flexible printed circuit board according to a third embodiment of the present invention. [Figure 9b] 11 is a perspective view showing a state in which a first extension line portion and a second extension line portion in a flexible printed circuit board according to a third embodiment of the present invention are bent. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The present invention will be described in detail below with reference to the accompanying drawings, in order to enable a person skilled in the art to easily carry out the present invention. However, the present invention may be embodied in various different forms, and is not limited to the following embodiments.

[0031] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may obscure the gist of the present invention will be omitted, and when referring to components in each drawing in this specification, the same or similar reference symbols will be used for the same or similar components throughout the specification.

[0032] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted in a manner consistent with the technical ideas of the present invention, based on the principle that an inventor can appropriately define the concept of a term in order to explain his or her invention in the best possible manner.

[0033] EMBODIMENT 1 Fig. 3 is an exploded perspective view showing the secondary battery module according to embodiment 1 of the present invention. Fig. 4 is a perspective view showing the main configuration of the secondary battery module according to embodiment 1 of the present invention. Fig. 5 is a perspective view showing a flexible printed circuit board, a fixing plate, and a connector of the secondary battery module according to embodiment 1 of the present invention. Fig. 6a is a side view showing the appearance of area A in Fig. 5 as seen from the side, and Fig. 6b is a plan view showing the appearance of area A in Fig. 5 as seen from above.

[0034] 3 and 4, a secondary battery module 10 according to the first embodiment of the present invention includes a pouch cell assembly 100, a busbar frame assembly (BFA) 200, and a flexible printed circuit board (FPC) 300. The pouch cell assembly 100 is formed by arranging a plurality of pouch cells in a thickness direction, and the busbar frame assembly 200 is coupled to one side and the other side of the pouch cell assembly 100, and the flexible printed circuit board 300 is coupled to the busbar frame assembly 200, and a film layer is laminated on at least one side of the metal layer.

[0035] In addition, the flexible printed circuit board 300 of the secondary battery module 10 according to the present invention includes a body portion 310 provided between the bus bar frame assemblies 200 respectively coupled to one side and the other side of the pouch cell assembly 100, and a sensing portion 320 extending from the body portion 310, extending from at least one of one side and the other side of the body portion 310 in a length direction and provided on one side and the other side of the body portion 310 in a width direction, for sensing the presence or absence of leakage of moisture or electrolyte.

[0036] As described above, the secondary battery module 10 according to the present invention can ensure the quality and safety of the battery by detecting and continuously monitoring whether the secondary battery module 10 is flooded or whether electrolyte of the pouch cells in the secondary battery module 10 has leaked by the sensing unit 320 having a simple structure extending from the body part 310. In particular, instead of mounting a separate sensor inside the module, the sensing unit 320 extends from the flexible printed circuit board 300 and senses whether electrolyte has leaked, thereby improving space utilization inside the module and maximizing the energy density of the module.

[0037] Each component of the secondary battery module 10 will be described in detail below.

[0038] 4 and 5, the sensing unit 320 may include a first extension line portion 321 extending toward one side of the width direction of the body portion 310, and a second extension line portion 322 extending toward the other side of the width direction of the body portion 310. That is, the sensing unit 320 may have two extension line portions for sensing.

[0039] Furthermore, the first extension line portion 321 and the second extension line portion 322 may extend integrally from the main body portion 310 of the flexible printed circuit board 300. For example, the main body portion 310 and the first extension line portion 321 and the second extension line portion 322 may be formed by cutting the sheet-like flexible printed circuit board 300. Thus, the first extension line portion 321 and the second extension line portion 322 may have a film layer laminated on at least one surface of a metal layer to correspond to the structure of the flexible printed circuit board 300.

[0040] 3 and 5, the first extension line portion 321 and the second extension line portion 322 are formed to be bendable, and in particular, in the secondary battery module according to the present invention, the first extension line portion 321 and the second extension line portion 322 may be bent along a periphery of the busbar frame assembly 200. More specifically, the first extension line portion 321 and the second extension line portion 322 may be bent along an inner periphery of the fixing plate 220 of the busbar frame assembly 200. The bent shape of the first extension line portion 321 and the second extension line portion 322 will be described in detail below together with the busbar frame assembly 200. As such, the first extension line portion 321 and the second extension line portion 322 are bent along the busbar frame assembly 200, thereby minimizing the space occupied in the module and maximizing the energy density, and the sensing sensitivity can be improved by being bent at the end of the pouch cell, which is an area where electrolyte is likely to leak, and at the periphery of the busbar frame assembly 200 abutting the end of the pouch cell.

[0041] In the secondary battery module 10 according to the first embodiment of the present invention, as shown in Fig. 5, the first extension line portion 321 and the second extension line portion 322 may be bent so that their ends face each other with a predetermined distance between them. In particular, as shown in Figs. 6a and 6b, when the secondary battery module 10 is submerged in water or electrolyte leakage occurs within the secondary battery module 10, the ends of the first extension line portion 321 and the second extension line portion 322 may both be immersed in the electrolyte H due to electrolyte or moisture H (hereinafter, referred to as electrolyte). At this time, the first extension line portion 321 and the second extension line portion 322 are electrically connected to each other by the electrolyte H, and the sensing unit 320 can detect this and sense whether electrolyte leakage has occurred.

[0042] Therefore, the predetermined interval may vary depending on the sensitivity of sensing the presence or absence of electrolyte leakage. For example, the closer the ends of the first extension line portion 321 and the second extension line portion 322 are, the smaller the amount of electrolyte H is required for the ends of the first extension line portion 321 and the second extension line portion 322 to be immersed together and electrically connected, and the farther the ends of the first extension line portion 321 and the second extension line portion 322 are, the larger the amount of electrolyte H is required to electrically connect them. In other words, the predetermined interval may be an interval that is designed according to the sensitivity of sensing the presence or absence of electrolyte leakage, which is set by the designer or manufacturer in consideration of the size of the module, the amount of electrolyte leakage that may cause corrosion of the battery or a fire, and the like.

[0043] Next, the structures of the first extension line portion 321 and the second extension line portion 322 will be described in more detail with reference to Figures 6a and 6b. The first extension line portion 321 may include a first exposed portion 321a where the metal layer is exposed at an end portion, and the second extension line portion 322 may include a second exposed portion 322a where the metal layer is exposed at an end portion. As described above, the first extension line portion 321 and the second extension line portion 322 may extend from a flexible printed circuit board and may have a structure in which a film layer is laminated on at least one surface of a metal layer. However, the first exposed portion 321a and the second exposed portion 322a may be formed by exposing the metal layer without being shielded by a film layer.

[0044] When the first exposed portion 321a and the second exposed portion 322a are both immersed in the electrolyte H, the first extension line portion 321 and the second extension line portion 322 are electrically connected. In this manner, the sensing unit 320 according to the present invention can sense whether the first exposed portion 321a and the second exposed portion 322a are electrically connected by the electrolyte H. Therefore, there is no need to separately provide a gas sensor that detects the presence or absence of leakage by sensing the electrolyte vapor as in the conventional technology. By extending only the sensing unit 320 from the main body portion 310 of the existing flexible printed circuit board 300 and providing the first exposed portion 321a and the second exposed portion 322a in the sensing unit 320, the presence or absence of electrolyte leakage can be sensed, ensuring the safety of the battery, and increasing the space utilization rate inside the module, minimizing dead space, and maximizing the energy density of the module.

[0045] Next, the bus bar frame assembly 200 will be described in detail with reference to Figures 3 to 5. The bus bar frame assembly 200 may include a bus bar 210, a fixing plate 220, and a cover plate 230.

[0046] First, the bus bar 210 may be made of metal and electrically connected to the electrode lead of the pouch assembly. In particular, the electrode lead may be inserted into a lead insertion portion 221 of a fixing plate 220, which will be described later, and then be bent and connected to the bus bar 210, which is attached to a bus bar attachment portion 222 in advance, by welding. The bus bar 210 may also be connected to the flexible printed circuit board 300, so that the flexible printed circuit board 300 can read the cell voltage transmitted from the electrode lead.

[0047] The fixing plate 220 is a type of extrusion, and may include a lead insertion portion 221 having a slit formed therein that penetrates the front and rear surfaces so that an electrode lead can be inserted therein, a bus bar attachment portion 222 formed on one side of the lead insertion portion 221, and a terrace portion 223 extending from a lower portion of the lead insertion portion 221 toward the pouch cell assembly 100. Here, the above-mentioned first exposed portion 321a and second exposed portion 322a may be placed on an upper surface of the terrace portion 223. When an electrolyte leaks from a pouch cell, it often flows around the bus bar frame assembly 200 or the fixing plate 220 of the bus bar frame assembly 200 located on both sides of the pouch assembly. Therefore, when the first exposed portion 321a and the second exposed portion 322a for detecting the electrolyte are placed on the upper surface of the terrace portion 223 of the fixed plate 220, the presence or absence of electrolyte leakage within the module can be more effectively detected with the first extension line portion 321 and the second extension line portion 322, which have flexibility, stably positioned.

[0048] Meanwhile, the cover plate 230 may cover the bus bar 210 attached to the bus bar mounting portion 222 of the fixed plate 220 and be coupled to the fixed plate 220, thereby protecting the bus bar 210 from external impacts and damage.

[0049] In addition, as shown in FIG. 3, the secondary battery module 10 according to the present invention may further include a module case 400 having both open ends in which the pouch cell assembly 100 and the bus bar frame assembly 200 are housed, and end plates 500 for covering both open ends of the module case 400.

[0050] The module case 400 (or monoframe) can serve as a housing that maintains the shape of the secondary battery module 10 and protects the pouch cell assembly 100, the flexible printed circuit board 300, and the bus bar frame assembly 200 housed therein. The module case 400 has a shape with both ends open, and the pouch cell assembly 100 can be inserted from both ends.

[0051] Also, the secondary battery module 10 according to the present invention may further include a connector 600 for transmitting a signal output from the flexible printed circuit board 300 to an external battery management system (Battery Management System, BMS). Here, the signal output from the flexible printed circuit board 300 may be a signal obtained by sensing the voltage of the cell transmitted from the bus bar 210, the temperature inside the module, or the above-mentioned leakage of the electrolyte. In particular, the secondary battery module 10 according to the present invention may sense whether the first exposed portion 321a and the second exposed portion 322a are electrically connected to each other by moisture or electrolyte in the sensing unit 320, and transmit the sensed signal to a micro controller unit (MCU) of the BMS in the connector 600, thereby detecting the leakage of the electrolyte.

[0052] EMBODIMENT 2 The second embodiment of the present invention is different from the first embodiment in that the terrace portion 223 of the fixing plate 220 according to the first embodiment includes a first inclined portion 223a and a second inclined portion 223b. Therefore, the other configurations of the secondary battery module 10 can be understood in the same manner as in the description of the first embodiment and the illustrations in Figures 3 to 6b, and the same effects can be expected therefrom.

[0053] Fig. 7 is a perspective view showing a fixing plate of a secondary battery module according to embodiment 2 of the present invention. Fig. 8a is a side view showing a first extension line portion, a second extension line portion, and a terrace portion of the secondary battery module according to embodiment 2 of the present invention as viewed from the side, and Fig. 8b is a plan view showing a first extension line portion, a second extension line portion, and a terrace portion of the secondary battery module according to embodiment 2 of the present invention as viewed from above.

[0054] 7, the terrace portion 223 of the fixing plate 220 according to the second embodiment of the present invention includes a first inclined portion 223a whose height decreases from one side to the center, and a second inclined portion 223b whose height decreases from the other side to the center. Also, referring to FIGS. 8a and 8b, the first exposed portion 321a is placed on the upper surface of the first inclined portion 223a, and the second exposed portion 322a is placed on the upper surface of the second inclined portion 223b.

[0055] Here, the first inclined portion 223a and the second inclined portion 223b may be flat, but are not necessarily limited thereto, and may be formed as curved surfaces. However, as described above, it is sufficient that the first inclined portion 223a is formed so that its height decreases from one side of the terrace portion 223 toward the center, and the second inclined portion 223b is formed so that its height decreases from the other side toward the center, the first inclined portion 223a and the second inclined portion 223b are connected in abutting contact with each other, and the terrace portion 223 has a curved central portion when viewed from the side.

[0056] In this way, since the secondary battery module 10 according to embodiment 2 of the present invention includes the first inclined portion 223a and the second inclined portion 223b, even if a small amount of electrolyte leaks, the electrolyte collects at the first inclined portion 223a and the second inclined portion 223b of the terrace portion 223, which is formed so as to become lower in height and concave toward the center, and this can be detected at the first exposed portion 321a and the second exposed portion 322a, thereby improving the ability to detect leakage or water ingress.

[0057] EMBODIMENT 3 The third embodiment of the present invention is different from the first and second embodiments in that the third embodiment is a flexible printed circuit board 300 included in the secondary battery module 10 according to the first and second embodiments. Therefore, the detailed configuration and effects of the flexible printed circuit board 300 described below can be understood in the same manner as the description of the first and second embodiments and the illustrations in Figs. 3 to 8b.

[0058] FIG. 9a is a perspective view showing a flexible printed circuit board 300 according to embodiment 3 of the present invention, and FIG. 9b is a perspective view showing a state in which the first extension line portion and the second extension line portion in the flexible printed circuit board 300 according to embodiment 3 of the present invention are bent.

[0059] 9a and 9b, a flexible printed circuit board 300 according to embodiment 3 of the present invention is a flexible printed circuit board (FPC) having a film layer laminated on at least one side of a metal layer, and includes a body portion 310 and a sensing portion 320 extending from the body portion 310 and provided from at least one of one and other sides based on a length direction of the body portion 310 to one and other sides based on a width direction of the body portion 310, for sensing the presence or absence of leakage of moisture or electrolyte.

[0060] In addition, the sensing unit 320 may include a first extension line portion 321 extending toward one side of the width direction of the body portion 310 and a second extension line portion 322 extending toward the other side of the width direction of the body portion 310.

[0061] In the flexible printed circuit board 300 according to embodiment 3 of the present invention, a first extension line portion 321 extends toward one side of a width direction reference of the main body portion 310 and is formed parallel to the length direction of the main body portion 310 in at least a portion of an area including an end portion, and a second extension line portion 322 extends toward the other side of a width direction reference of the main body portion 310 and is formed parallel to the length direction of the main body portion 310 in at least a portion of an area including an end portion.

[0062] In this way, the first extension line portion 321 and the second extension line portion 322 may extend integrally from the main body portion 310 of the flexible printed circuit board 300, and for example, the main body portion 310 and the first extension line portion 321 and the second extension line portion 322 may be formed by cutting the sheet-like flexible printed circuit board 300. Thus, when the first extension line portion 321 is formed parallel to the length direction of the main body portion 310 in at least a portion of the region including the end portion, and the second extension line portion 322 is cut so as to be parallel to the length direction of the main body portion 310 in at least a portion of the region including the end portion, the cut area of ​​the sheet-like flexible printed circuit board 300 can be minimized, thereby maximizing the product yield and reducing costs.

[0063] Meanwhile, the first extension line portion 321 and the second extension line portion 322 may be formed to be bendable. Since the first extension line portion 321 and the second extension line portion 322 are formed to be bendable in this manner, when the flexible printed circuit board 300 is folded, the overall volume occupied by the sensing unit 320 of the flexible printed circuit board 300 can be minimized, and the flexible printed circuit board 300 can be mounted in a state in which the space occupied by the sensing unit 320 in various types of devices or frames is minimized, and in particular, as described above in the first embodiment, the flexible printed circuit board 300 can be mounted in a module to maximize the energy density of the battery.

[0064] Alternatively, the first extension line portion 321 may include a first exposed portion 321a at an end where the metal layer is exposed, and the second extension line portion 322 may include a second exposed portion 322a at an end where the metal layer is exposed.

[0065] Here, the first extension line portion 321 and the second extension line portion 322 may be bent so that their respective ends face each other with a predetermined distance apart, and more specifically, the first extension line portion 321 and the second extension line portion 322 are bent, but the first exposed portion 321a and the second exposed portion 322a may be bent so that they face each other with a predetermined distance apart.

[0066] The sensing unit 320 according to the third embodiment of the present invention can sense whether the first exposed portion 321a and the second exposed portion 322a are electrically connected to each other by moisture or electrolyte. That is, when the first exposed portion 321a and the second exposed portion 322a are both immersed in moisture or electrolyte, they are electrically connected to each other, thereby making it possible to sense whether the electrolyte is leaking or submerged.

[0067] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and various implementations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the appended claims. [Explanation of symbols]

[0068] 10 Secondary battery module 100 Pouch Cell Assembly 200 Busbar Frame Assembly 210 Busbar 220 Fixing plate 221 Lead insertion section 222 Busbar mounting part 223 Terrace 223a 1st slope 223b 2nd slope 230 Cover Plate 300 Flexible Printed Circuit Board 310 Main body part 320 Sensing section 321 First Extension Line Section 321a 1st exposed part 322 2nd Extension Line Section 322a 2nd exposed part 400 module case 500 End Plate 600 Connectors H Electrolyte or moisture

Claims

1. a pouch cell assembly formed by arranging a plurality of pouch cells in a thickness direction; a bus bar frame assembly coupled to one side and the other side of the pouch cell assembly, a flexible printed circuit board (FPC) coupled to the bus bar frame assembly and having a film layer laminated on at least one surface of a metal layer, The flexible printed circuit board is a body portion provided between bus bar frame assemblies coupled to one side and the other side of the pouch cell assembly, a sensing unit extending from the main body portion, the sensing unit extending from at least one of one side and the other side of a length direction reference of the main body portion, the sensing unit being provided on one side and the other side of a width direction reference of the main body portion, and sensing the presence or absence of leakage of moisture or electrolyte.

2. The sensing unit is A first extension line portion extending toward one side of a width direction reference of the main body portion; The secondary battery module according to claim 1 , further comprising: a second extension line portion extending toward the other side of the width direction reference of the main body portion.

3. The first extension line portion and the second extension line portion are The secondary battery module according to claim 2 , wherein the secondary battery module is bent along a periphery of the bus bar frame assembly.

4. The first extension line portion and the second extension line portion are The secondary battery module according to claim 3 , wherein the respective ends are bent so as to face each other with a predetermined distance therebetween.

5. The first extension line portion is a first exposed portion at an end portion of the metal layer; The second extension line portion is The secondary battery module according to claim 3 , further comprising a second exposed portion at which the metal layer is exposed at an end portion.

6. The sensing unit is The secondary battery module according to claim 5 , wherein whether or not the first exposed portion and the second exposed portion are electrically connected is sensed by moisture or an electrolyte.

7. The bus bar frame assembly includes: a bus bar electrically coupled to an electrode lead of the pouch cell assembly; a lead insertion portion having a slit penetrating a front and rear surface thereof so that the electrode lead can be inserted therein; a bus bar attachment portion formed on one side of the lead insertion portion; and a fixing plate having a terrace portion extending from a lower portion of the lead insertion portion toward the pouch cell assembly; Including, The first exposed portion and the second exposed portion are The secondary battery module according to claim 5 , which is placed on an upper surface of the terrace portion.

8. The bus bar frame assembly includes: The secondary battery module of claim 7 , further comprising a cover plate covering the bus bar and coupled to the fixing plate.

9. a module case having both ends open and housing the pouch cell assembly and the bus bar frame assembly therein; The secondary battery module of claim 1 , further comprising end plates covering both open ends of the module case.

10. The secondary battery module of claim 1 , further comprising a connector for transmitting a signal output from the flexible printed circuit board to an external battery management system (BMS).

11. The terrace portion is A first inclined portion whose height decreases from one side to the center; a second inclined portion whose height decreases from the other side to the center, The secondary battery module according to claim 7 , wherein the first exposed portion is placed on an upper surface of the first inclined portion, and the second exposed portion is placed on an upper surface of the second inclined portion.

12. In a flexible printed circuit board (FPC) in which a film layer is laminated on at least one surface of a metal layer, A main body part, a sensing portion extending from the main body portion, the sensing portion being provided from at least one of one side and the other side of a length direction reference of the main body portion to one side and the other side of a width direction reference of the main body portion, and sensing the presence or absence of leakage of moisture or electrolyte.

13. The sensing unit is A first extension line portion extending toward one side of a width direction reference of the main body portion; The flexible printed circuit board according to claim 12 , further comprising: a second extension line portion extending toward the other side of the width direction reference of the main body portion.

14. The first extension line portion is The main body portion extends toward one side of a width direction reference and is formed parallel to the length direction of the main body portion in at least a portion of the region including the end portion, The second extension line portion is The flexible printed circuit board according to claim 13 , wherein the flexible printed circuit board extends toward the other side of the width direction reference of the main body portion and is formed parallel to the longitudinal direction of the main body portion in at least a portion of the region including the end portion.

15. The first extension line portion and the second extension line portion are The flexible printed circuit board according to claim 13 , which is formed to be bendable.

16. The first extension line portion is a first exposed portion at an end portion of the metal layer; The second extension line portion is The flexible printed circuit board according to claim 13 , further comprising a second exposed portion at which the metal layer is exposed at an end portion.

17. The sensing unit is The flexible printed circuit board according to claim 16 , wherein whether or not the first exposed portion and the second exposed portion are electrically connected is sensed by moisture or an electrolyte.

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