Flexible printed circuit board and secondary battery module including the 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 the contents disclosed in the document of the Korean Patent Application are incorporated herein by reference in their entirety.

[0002] The present invention relates to a flexible printed circuit board and a secondary battery module including the same, and more particularly, to a flexible printed circuit board and a secondary battery module including the same, which can detect whether the secondary battery module is flooded or whether the electrolyte of the pouch cell leaks in the secondary battery module and continuously monitor the same.

Background Art

[0003] A secondary battery means a battery that can be charged and discharged, unlike a primary battery that cannot be charged. Types of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, lithium-ion polymer batteries, and the like. Such 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 power such as electric vehicles and hybrid vehicles, and in power storage devices for storing surplus generated power and newly renewable energy and backup power storage devices.

[0004] Such secondary batteries are classified into a pouch type and a can type 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 amorphous flexible polymer material. The can type houses the electrode assembly in a case made of a shaped material such as metal or plastic.

[0005] Rechargeable batteries can be composed of cells, modules, or packs, depending on the unit in which they are grouped. First, a cell is the basic unit of a rechargeable battery that can be used by charging and discharging electrical energy, and may be a pouch-type or can-type rechargeable battery as described above.

[0006] Figure 1 is a perspective view showing a conventional secondary battery module. Figure 2 is a perspective view showing the main components of a conventional secondary battery module. Referring to Figures 1 and 2, 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, as shown in Figure 1, in order to protect the cells from external shocks, heat, vibrations, etc. In particular, the module may include not only the cell assemblies 2, but also a fixing plate 3 (or busbar frame assembly) to which busbars that electrically connect the cell assemblies are attached and which secures the pouch cell assemblies, and a circuit board 4 that measures the voltage, temperature, etc. of the cells within the module and transmits this information to the outside.

[0007] Furthermore, the pack represents the final form of the battery system, completed by equipping the secondary battery module with various control and protection systems such as a BMS and cooling system.

[0008] On the other hand, with pouch-type cells, the electrolyte injected into the cell may leak within the module due to poor sealing of the pouch or damage to the pouch. In such cases, corrosion of the pouch occurs, which can lead to a decrease in battery performance or a vehicle fire, reducing the reliability of the product quality and seriously threatening user safety.

[0009] Therefore, during the manufacturing process, it is necessary to check whether or not the electrolyte from the cells has leaked within the assembled module, and after the module or pack is installed in the vehicle, continuous monitoring is required in the field to ensure safety. [Overview of the project] [Problems that the invention aims to solve]

[0010] The present invention was made to solve the above problems, and the object of the present invention is to provide a flexible printed circuit board and a secondary battery module including the same that can detect and continuously monitor whether or not a secondary battery module has been submerged in water or whether or not the electrolyte of a pouch cell has leaked inside the secondary battery module by simple structural modifications, thereby ensuring the quality and safety of the battery and maximizing the utilization of space and energy density inside the module. [Means for solving the problem]

[0011] A secondary battery module according to Embodiment 1 of the present invention includes a pouch cell assembly formed by arranging a plurality of pouch cells in the thickness direction, busbar frame assemblies coupled to one side and the other side of the pouch cell assembly, and a flexible printed circuit board (FPC) coupled to the busbar frame assembly, in which a film layer is laminated on at least one surface of a metal layer, wherein the flexible printed circuit board includes a main body portion provided between the busbar frame assemblies coupled to one side and the other side of the pouch cell assembly, and a sensing portion extending from the main body portion, but extending from at least one of the main body portion's longitudinal reference side and the main body portion's width reference side, and provided on the main body portion's width reference side, for sensing the presence or absence of moisture or electrolyte leakage.

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

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

[0014] The first extension line portion and the second extension line portion may be bent so that their respective ends are separated by a predetermined distance and face each other.

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

[0016] The sensing unit may be configured to sense whether the first exposed portion and the second exposed portion are electrically connected by moisture or an electrolyte.

[0017] The busbar frame assembly includes a busbar electrically coupled to the electrode leads of the pouch assembly, a lead insertion portion having a slit shape that penetrates the front and rear surfaces for the insertion of the electrode leads, a busbar mounting portion formed on one side of the lead insertion portion, and a fixing plate having a terrace portion that extends from the lower part of the lead insertion portion toward the pouch cell assembly, wherein the first exposed portion and the second exposed portion may be placed on the upper surface of the terrace portion.

[0018] The busbar frame assembly may further include a cover plate that covers the busbar and is coupled to the fixing plate.

[0019] The secondary battery module may further include a module case with open ends that houses the pouch cell assembly and the busbar frame assembly inside, and end plates that cover the open ends of the module case.

[0020] The secondary battery module may further include a connector that transmits signals 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 includes a first inclined portion whose height decreases from one side towards the center, and a second inclined portion whose height decreases from the other side towards the center, wherein the first exposed portion may be placed on the upper surface of the first inclined portion, and the second exposed portion may be placed on the upper surface of the second inclined portion.

[0022] The flexible printed circuit board according to Embodiment 2 of the present invention is a flexible printed circuit board (FPC) in which a film layer is laminated on at least one surface of a metal layer, and includes a main body portion and a sensing portion that extends from the main body portion and is provided on one side and the other side in the width direction of the main body portion from at least one of one side and the other side in the length direction reference of the main body portion, and senses the presence or absence of leakage of moisture or electrolyte solution.

[0023] The sensing portion may include a first extension line portion that extends toward one side in the width direction of the main body portion and a second extension line portion that extends toward the other side in the width direction of the main body portion.

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

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

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

[0027] The sensing portion may sense whether or not the first exposed portion and the second exposed portion are electrically connected by moisture or electrolyte solution.

Advantages 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 the thickness direction, a bus bar frame assembly coupled to one side and the other side of the pouch cell assembly, respectively, and 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 includes a main body portion provided between the bus bar frame assemblies coupled to one side and the other side of the pouch cell assembly, respectively, and a sensing portion extending from the main body portion and extending from at least one of one side and the other side of the main body portion in the length direction reference, and provided on one side and the other side of the main body portion in the width direction reference for sensing the presence or absence of leakage of moisture or electrolyte. With such a simple structural change, it is possible to detect whether the secondary battery module is flooded or whether the electrolyte of the pouch cell leaks in the secondary battery module, and continuously monitor it, ensuring the quality and safety of the battery, and maximizing the space utilization degree and energy density inside the module.

Brief Description of the Drawings

[0029] [Figure 1] It is a perspective view showing a conventional secondary battery module. [Figure 2] It is a perspective view showing the main configuration of a conventional secondary battery module. [Figure 3] It is an exploded perspective view showing the secondary battery module according to Embodiment 1 of the present invention. [Figure 4] It is a perspective view showing the main configuration of the secondary battery module according to Embodiment 1 of the present invention. [Figure 5] It is a perspective view showing the flexible printed circuit board, fixed plate, and connector of the secondary battery module according to Embodiment 1 of the present invention. [Figure 6a] It is a side view showing a state of viewing the A region of FIG. 5 from the side. [Figure 6b] It is a plan view showing a state of viewing the A region of FIG. 5 from above. [Figure 7]This is a perspective view showing a fixing plate for a secondary battery module according to Embodiment 2 of the present invention. [Figure 8a] This is a side view showing the first extension line section, the second extension line section, and the terrace section of a secondary battery module according to Embodiment 2 of the present invention, as viewed from the side. [Figure 8b] This is a plan view showing the first extension line section, the second extension line section, and the terrace section of a secondary battery module according to Embodiment 2 of the present invention, as seen from above. [Figure 9a] This is a perspective view showing a flexible printed circuit board according to Embodiment 3 of the present invention. [Figure 9b] This is a perspective view showing the first extension line portion and the second extension line portion of a flexible printed circuit board according to Embodiment 3 of the present invention in a bent state. [Modes for carrying out the invention]

[0030] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention can be realized in a variety of different forms and is not limited to or restricted to the following embodiments.

[0031] In order to clearly explain the present invention, detailed descriptions of parts unrelated to the description or related prior art that may obscure the gist of the invention have been omitted. In this specification, when assigning reference numerals to components in each drawing, the same or similar reference numerals are assigned to components that are the same or similar throughout the specification.

[0032] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings. Rather, based on the principle that inventors can appropriately define the concepts of terms in order to best describe their invention, they should be interpreted in a way that is consistent with the technical idea of ​​the present invention.

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

[0034] Referring to Figures 3 and 4, the secondary battery module 10 according to Embodiment 1 of the present invention includes a pouch cell assembly 100, a busbar frame assembly 200 (BFA), and a flexible printed circuit board 300 (FPC). The pouch cell assembly 100 is formed by arranging a plurality of pouch cells in the thickness direction, the busbar frame assembly 200 is coupled to the pouch cell assembly 100 on one side and the other side, the flexible printed circuit board 300 is coupled to the busbar frame assembly 200, and a film layer is laminated on at least one surface of the metal layer.

[0035] Furthermore, the flexible printed circuit board 300 of the secondary battery module 10 according to the present invention includes a main body portion 310 provided between busbar frame assemblies 200 which are coupled on one side and the other side of the pouch cell assembly 100, respectively, and a sensing portion 320 that extends from the main body portion 310 but extends from at least one of the one and the other sides of the main body portion 310 based on the length direction, and is provided on the one and the other side of the main body portion 310 based on the width direction, and senses whether or not there is leakage of moisture or electrolyte.

[0036] Thus, the secondary battery module 10 according to the present invention can ensure the quality and safety of the battery by detecting whether the secondary battery module 10 has been submerged in water or whether the electrolyte of the pouch cell has leaked inside the secondary battery module 10, using a sensing unit 320 with a simple structure extending from the main body 310, and by continuously monitoring this. In particular, by having the sensing unit 320 extend from the flexible printed circuit board 300, rather than installing a separate sensor inside the module, and sensing the presence or absence of electrolyte leakage, the utilization of space inside the module can be increased, and the energy density of the module can be maximized.

[0037] The following describes in detail each component of the secondary battery module 10.

[0038] First, referring to Figures 4 and 5, the sensing unit 320 may include a first extension line portion 321 extending toward one side of the main body portion 310 relative to the width direction, and a second extension line portion 322 extending toward the other side of the main body portion 310 relative to the width direction. In other words, 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 a sheet-like flexible printed circuit board 300. Therefore, 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 the metal layer to correspond to the structure of the flexible printed circuit board 300.

[0040] On the other hand, referring to Figures 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 the periphery of the busbar frame assembly 200. More specifically, they may be bent along the 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. By bending the first extension line portion 321 and the second extension line portion 322 along the busbar frame assembly 200 in this way, the space occupied within the module can be minimized and the energy density can be maximized, and the sensing sensitivity can be increased by bending at the ends of the pouch cells, which are areas where electrolyte is prone to leakage, and at the periphery of the busbar frame assembly 200 that abuts the ends of the pouch cells.

[0041] In the secondary battery module 10 according to Embodiment 1 of the present invention, as shown in Figure 5, the first extension line portion 321 and the second extension line portion 322 may be bent so that their respective ends are separated by a predetermined distance from each other and face each other. More specifically, as shown in Figures 6a and 6b, if the secondary battery module 10 is submerged in water or if electrolyte leakage occurs within the secondary battery module 10, the ends of both the first extension line portion 321 and the second extension line portion 322 may become immersed in the 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 or not electrolyte leakage has occurred.

[0042] Therefore, the predetermined interval can be changed by the sensitivity of sensing whether or not electrolyte leakage has occurred. For example, the closer the ends of the first extension line section 321 and the second extension line section 322 are, the more an amount of electrolyte H is needed to immerse both ends of the first extension line section 321 and the second extension line section 322 and electrically connect them. The further apart the ends of the first extension line section 321 and the second extension line section 322 are, the more electrolyte H is needed for them to electrically connect. In other words, the predetermined interval may be an interval designed by the designer or manufacturer, who takes into account the size of the module, battery corrosion, or the amount of electrolyte leakage that could cause a fire, and sets the sensitivity for sensing whether or not electrolyte leakage has occurred.

[0043] Next, with reference to Figures 6a and 6b, the structures of the first extension line portion 321 and the second extension line portion 322 will be described in more detail. The first extension line portion 321 may include a first exposed portion 321a where the metal layer is exposed at its end, and the second extension line portion 322 may include a second exposed portion 322a where the metal layer is exposed at its end. As described above, the first extension line portion 321 and the second extension line portion 322 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 the 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 the 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 way, the sensing unit 320 according to the present invention can sense whether or not 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 senses electrolyte vapor to detect the presence or absence of leakage, as in the conventional method. 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, it is possible to sense the presence or absence of electrolyte leakage, ensure the safety of the battery, increase the utilization of space inside the module, minimize dead space, and maximize the energy density of the module.

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

[0046] First, the busbar 210 is made of metal and may be electrically coupled to the electrode leads of the pouch assembly. More specifically, the electrode leads may be inserted into the lead insertion portion 221 of the fixing plate 220 (described later) and then welded to the busbar 210, which is pre-attached to the busbar mounting portion 222 in a bent state. The busbar 210 may also be connected to the flexible printed circuit board 300, thereby allowing the flexible printed circuit board 300 to read the cell voltage transmitted from the electrode leads.

[0047] The fixing plate 220 is a type of injection molding and may include a lead insertion portion 221 with slits that penetrate its front and rear surfaces for the insertion of electrode leads, a busbar mounting portion 222 formed on one side of the lead insertion portion 221, and a terrace portion 223 extending from the lower part of the lead insertion portion 221 toward the pouch cell assembly 100. Here, the first exposed portion 321a and the second exposed portion 322a described above may be placed on the upper surface of the terrace portion 223. When electrolyte leaks from the pouch cell, it frequently flows around the busbar frame assembly 200 or the fixing plate 220 of the busbar frame assembly 200, which are generally 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 detected more effectively while the flexible first extension line portion 321 and the second extension line portion 322 are in a stable position.

[0048] On the other hand, the cover plate 230 covers the busbar 210 attached to the busbar mounting portion 222 of the fixing plate 220 and may be coupled to the fixing plate 220, thereby protecting the busbar 210 from external impacts and damage.

[0049] In addition, the secondary battery module 10 according to the present invention may further include, as shown in Figure 3, a module case 400 in which both ends are open and the pouch cell assembly 100 and the busbar frame assembly 200 are housed inside, and end plates 500 that cover both open ends of the module case 400.

[0050] The module case 400 (or monoframe) can maintain the shape of the secondary battery module 10 and serve as a housing that protects the pouch cell assembly 100, flexible printed circuit board 300, and busbar frame assembly 200 housed inside. The module case 400 has an open shape at both ends, allowing the pouch cell assembly 100 to be inserted from both ends.

[0051] Furthermore, the secondary battery module 10 according to the present invention may further include a connector 600 that transmits signals output from the flexible printed circuit board 300 to an external battery management system (BMS). Here, the signals output from the flexible printed circuit board 300 may be the voltage of the cells transmitted from the busbar 210, the temperature inside the module, or signals sensing the presence or absence of electrolyte leakage as described above. In particular, the secondary battery module 10 according to the present invention can detect the presence or absence of electrolyte leakage by sensing in the sensing unit 320 whether the first exposed portion 321a and the second exposed portion 322a are electrically connected by moisture or electrolyte, and transmitting this to the MCU (Micro Controller Unit) of the BMS via the connector 600.

[0052] Embodiment 2 Embodiment 2 of the present invention differs from Embodiment 1 in that the terrace portion 223 of the fixing plate 220 includes a first inclined portion 223a and a second inclined portion 223b. Therefore, the other components of the secondary battery module 10 can be understood in the same way as described in Embodiment 1 above and illustrated in Figures 3 to 6b, and the effects therefrom can be expected to be the same.

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

[0054] Referring to Figure 7, the terrace portion 223 of the fixing plate 220 according to Embodiment 2 of the present invention includes a first inclined portion 223a whose height decreases from one side towards the center, and a second inclined portion 223b whose height decreases from the other side towards the center. Also, referring to Figures 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 to that, and may be formed as curved surfaces. However, as described above, it is sufficient that the first inclined portion 223a is formed such that its height decreases from one side of the terrace portion 223 towards the center, and the second inclined portion 223b is formed such that its height decreases from the other side towards the center, and that the first inclined portion 223a and the second inclined portion 223b are connected in contact with each other, and that when the terrace portion 223 is viewed from the side, the central part has a curved shape.

[0056] Thus, the secondary battery module 10 according to Embodiment 2 of the present invention includes a first inclined portion 223a and a second inclined portion 223b. As a result, even if a small amount of electrolyte leaks, the electrolyte will accumulate in the first inclined portion 223a and the second inclined portion 223b of the terrace portion 223, which is formed by a depression that decreases in height towards the center. This allows for detection of the leak or water ingress at the first exposed portion 321a and the second exposed portion 322a, improving the ability to detect leaks or water ingress.

[0057] Embodiment 3 Embodiment 3 of the present invention differs from Embodiments 1 and 2 in that it is a flexible printed circuit board 300 included in the secondary battery module 10 according to Embodiments 1 and 2. Therefore, the detailed configuration and effects of the flexible printed circuit board 300 described below can be understood in the same way as the descriptions and illustrations in Embodiments 1 and 2 and in Figures 3 to 8b.

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

[0059] Referring to Figures 9a and 9b, the flexible printed circuit board 300 according to Embodiment 3 of the present invention is a flexible printed circuit board 300 (FPC) in which a film layer is laminated on at least one surface of a metal layer, and includes a main body portion 310 and a sensing portion 320 that extends from the main body portion 310 and is provided on at least one side of the main body portion 310 relative to the length direction, and on one side of the main body portion 310 relative to the width direction, for sensing the presence or absence of moisture or electrolyte leakage.

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

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

[0062] Thus, 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 a sheet-like flexible printed circuit board 300. Therefore, if the first extension line portion 321 is formed parallel to the longitudinal direction of the main body portion 310 in at least a portion of the area including the end portion, and the second extension line portion 322 is formed parallel to the longitudinal direction of the main body portion 310 in at least a portion of the area including the end portion, the cutting area of ​​the sheet-like flexible printed circuit board 300 can be minimized, thereby maximizing product yield and reducing costs.

[0063] On the other hand, the first extension line portion 321 and the second extension line portion 322 may be formed to be bendable. By forming the first extension line portion 321 and the second extension line portion 322 to be bendable in this way, the overall area occupied by the sensing portion 320 of the flexible printed circuit board 300 can be minimized when bent, and it can be mounted in a state that minimizes the space it occupies in various types of devices or frames, and in particular, as described above in Embodiment 1, it can be mounted in a module to maximize the energy density of the battery.

[0064] In addition, the first extension line portion 321 may include a first exposed portion 321a at its end where the metal layer is exposed, and the second extension line portion 322 may include a second exposed portion 322a at its 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 are separated by a predetermined distance and face each other. More specifically, the first extension line portion 321 and the second extension line portion 322 may be bent so that the first exposed portion 321a and the second exposed portion 322a are separated by a predetermined distance and face each other.

[0066] The sensing unit 320 according to Embodiment 3 of the present invention can sense whether the first exposed portion 321a and the second exposed portion 322a are electrically connected by moisture or electrolyte. That is, when both the first exposed portion 321a and the second exposed portion 322a are immersed in moisture or electrolyte, they become electrically connected to each other, thereby allowing the sensing of whether or not there is leakage or ingress of electrolyte.

[0067] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the equivalent scope of the technical concept and the appended claims by persons with ordinary skill in the art to which the present invention pertains. [Explanation of Symbols]

[0068] 10 Secondary battery modules 100 pouch cell assemblies 200 Busbar Frame Assembly 210 Busbar 220 Fixing Plate 221 Lead insertion section 222 Busbar mounting section 223 Terrace section 223a 1st slope 223b 2nd slope 230 Cover Plate 300 Flexible Printed Circuit Boards 310 Main body part 320 Sensing Unit 321 First extension line section 321a 1st exposed part 322 Second extension line section 322a 2nd exposed part 400 Module Case 500 End Plate 600 connectors H electrolyte or water

Claims

1. A pouch cell assembly formed by arranging multiple pouch cells in the thickness direction, A busbar frame assembly is connected to one side and the other side of the pouch cell assembly, respectively. The busbar frame assembly is coupled to a flexible printed circuit board (FPC) in which a film layer is laminated on at least one surface of a metal layer, The aforementioned flexible printed circuit board is A main body portion provided between the busbar frame assemblies that are joined on one side and the other side of the pouch cell assembly, A secondary battery module, comprising a sensing unit extending from the main body portion, the sensing unit extending from at least one of the main body portion's longitudinal reference side and the main body portion's width reference side and provided on the main body portion's width reference side, for sensing the presence or absence of moisture or electrolyte leakage.

2. The sensing unit is, The first extension line portion extends toward one side of the main body portion with respect to the width direction, 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 section and the second extension line section are The secondary battery module according to claim 2, which is bent along the periphery of the busbar frame assembly.

4. The first extension line section and the second extension line section are The secondary battery module according to claim 3, wherein each end is bent so that it faces each other while being separated by a predetermined distance.

5. The first extension line section is, The end portion includes a first exposed portion in which the metal layer is exposed, The second extension line section is, The secondary battery module according to claim 3, further comprising a second exposed portion at the end where the metal layer is exposed.

6. The sensing unit is, The secondary battery module according to claim 5, which senses whether the first exposed portion and the second exposed portion are electrically connected by moisture or electrolyte.

7. The aforementioned busbar frame assembly is A busbar electrically coupled to the electrode leads of the pouch cell assembly, A lead insertion portion having a slit that penetrates the front and rear surfaces so that the electrode lead can be inserted, a busbar mounting portion formed on one side of the lead insertion portion, and a fixing plate having a terrace portion that extends from the lower part of the lead insertion portion toward the pouch cell assembly, Includes, The first exposed portion and the second exposed portion are The secondary battery module according to claim 5, which is placed on the upper surface of the terrace portion.

8. The aforementioned busbar frame assembly is The secondary battery module according to claim 7, further comprising a cover plate that covers the busbar and is coupled to the fixing plate.

9. A module case with both ends open, in which the pouch cell assembly and the busbar frame assembly are housed, The secondary battery module according to claim 1, further comprising end plates that cover the open ends of the module case.

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

11. The aforementioned terrace section is A first inclined section where the height decreases from one side towards the center, It includes a second inclined section where the height decreases as you move from the other side towards the center, The secondary battery module according to claim 7, wherein the first exposed portion is placed on the upper surface of the first inclined portion, and the second exposed portion is placed on the 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, The main body and A sensing unit extending from the main body portion, the sensing unit includes a sensing unit that senses the presence or absence of leakage of moisture or electrolyte, provided on at least one of the longitudinal and non-longitudinal sides of the main body portion, and on the widthwise side of the main body portion, The sensing unit is, The first extension line portion extends toward one side of the main body portion with respect to the width direction, A flexible printed circuit board, including a second extension line portion extending toward the other side of the width direction reference of the main body portion.

13. The first extension line section is, The main body portion extends toward one side relative to the width direction and is formed parallel to the length direction of the main body portion in at least a portion of the area including the end, The second extension line section is, The flexible printed circuit board according to claim 12, which extends toward the other side of the width direction of the main body portion and is formed parallel to the length direction of the main body portion in at least a portion of the area including the end portion.

14. The first extension line section and the second extension line section are A flexible printed circuit board according to claim 12, which is formed to be bendable.

15. The first extension line section is, The end portion includes a first exposed portion in which the metal layer is exposed, The second extension line section is, The flexible printed circuit board according to claim 12, further comprising a second exposed portion at the end where the metal layer is exposed.

16. The sensing unit is, The flexible printed circuit board according to claim 15, which senses whether the first exposed portion and the second exposed portion are electrically connected by moisture or an electrolyte.

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