Electrolyte leakage detector and battery module including the same

Abstract

The present invention relates to a sensor that is disposed inside a battery module or a battery pack and detects electrolyte leaking from a battery cell, and to a battery module or a battery pack that includes the sensor.

Description

[Technical Field]

[0001] The present invention relates to an electrolyte leakage detector and a battery module including the same, and more particularly to a detector disposed inside a battery module or a battery pack for detecting electrolyte leaking from a battery cell, and a battery module or a battery pack including the detector. [Background technology]

[0002] A secondary battery is configured as a battery pack by connecting a plurality of battery cells in series and / or parallel to form a battery module according to the required output voltage or charge / discharge capacity, and further connecting these battery modules.

[0003] Pouch-type batteries, in which a stack-type or stack / folding-type electrode assembly is housed in a pouch-type battery case made of a laminate sheet, are also widely used in battery modules or battery packs due to their advantages of low manufacturing costs and high energy density.

[0004] Pouch-type batteries are typically manufactured by molding a laminate sheet including an outer coating layer, a metal barrier layer, and an inner adhesive layer into a battery case. An electrode assembly and an electrolyte are placed in a receiving portion of the laminate sheet and then sealed to form a pouch-type battery.

[0005] As shown in Figure 1, a pouch-type battery 50 has an electrode assembly 20 housed in a housing 13 of a battery case 10, which is made up of a pouch-type lower section 11 and a pouch-type upper section 12. The electrode assembly 20 has positive and negative electrode tabs 21 and 22 welded to two electrode leads 31 and 32, respectively, which are exposed to the outside of the battery case 10. The outer periphery of the battery case 10 is sealed with a pair of insulating films 41 and 42 interposed between the upper and lower sections of the electrode leads 31 and 32.

[0006] 1 illustrates an example in which the positive and negative electrode tabs 21, 22 are positioned in the same direction. That is, in FIG. 1, the positive and negative electrode tabs 21, 22 are positioned only in the +x direction on a plane parallel to the yz plane of the electrode assembly 20. If the positive and negative electrode tabs 21, 22 are positioned in different directions on the electrode assembly 20, that is, if they are positioned in the +x and −x directions on a plane parallel to the yz plane of the electrode assembly 20 in FIG. 1, the folded edge of the battery case, i.e., the folded edge located on the y-axis in FIG. 1, rotates counterclockwise and is positioned on a plane located on the x-axis.

[0007] Pouch-type batteries, in which electrode tabs are located on both sides of an electrode assembly, are often used in battery modules or battery packs. A battery cell assembly is formed by vertically arranging a plurality of pouch-type batteries, each with a positive and negative tab on one side, and bus bars are disposed on both ends of the battery cell assembly to electrically connect the positive and negative tabs, or more specifically, the positive and negative leads. The bus bars disposed on both ends of the battery cell assembly may be electrically connected to each other.

[0008] 2 is an exploded perspective view schematically illustrating the structure of a conventional battery module 100. Referring to FIG. 2, the battery module 100 includes a battery cell assembly 110 formed by stacking battery cells 111, each having electrode leads 112 disposed on both sides thereof; a bus bar frame 120 including a first vertical plate 121 and a second vertical plate 122 disposed on both sides of the battery cell assembly 110 corresponding to the positions of the electrode leads 112 of the battery cells 111, and an upper plate 123 connected to the first vertical plate 121 and the second vertical plate 122 and disposed on the top of the battery cell assembly 110; and a monoframe 130 formed in a square tube shape so that the battery cell assembly 110, with the bus bar frame 120 attached, can be inserted into an internal space. A side frame 140 is then coupled to the monoframe to complete the battery module 100.

[0009] The bus bars 126 are disposed on the first vertical plate 121 and the second vertical plate 122. The bus bars 126 are used to connect the plurality of battery cells 111 in series or in parallel. The bus bars 126 are conductors with low impedance and high current capacity, and a plurality of bus bars 126 are arranged side by side in the direction in which the plurality of battery cells 111 are stacked, thereby connecting the battery cells 111 in series or in parallel.

[0010] Although the bus bar 126 has a plate-like structure with a uniform thickness, it is not limited thereto and may be modified to have various structures that allow electrical connection.

[0011] In addition to pouch-type batteries, cylindrical or prismatic batteries can also be used to form battery modules or battery packs. After multiple cylindrical or prismatic batteries are vertically arranged, bus bars can be placed on the top and / or bottom surfaces where the electrodes are located.

[0012] After the battery cells and the bus bars are connected, a separate case may be provided on the outside to fix them.

[0013] When pouch-type batteries, cylindrical batteries, and prismatic batteries are used in battery modules or battery packs, electrolyte leakage from the battery cells can cause various problems. Leaking electrolyte not only reduces the electrical performance of the battery module or battery pack, but also poses the risk of corrosion, short circuits, and fires. In battery modules containing multiple battery cells, early detection of these issues is crucial due to safety concerns.

[0014] Patent Document 1 relates to an apparatus and method for detecting leakage of battery cell electrolyte and protecting a battery pack. Patent Document 1 relates to an apparatus and method for detecting leakage of battery cell electrolyte and protecting a battery pack. The apparatus includes an electrolyte absorbing member 10 attached to the outside of a battery cell to absorb electrolyte leaking from the battery cell and to have conductive properties due to the absorption of the electrolyte, a power supply 20 connected to both ends of the electrolyte absorbing member and applying power, a resistor 30 connected between the electrolyte absorbing member and the power supply, a sensing unit 40 for detecting whether a current flows through the resistor, and a control unit 50 for cutting off the charge / discharge current by blowing a fuse on a charge / discharge path of the battery pack when the sensing unit detects that a current flows through the resistor.

[0015] Although Patent Document 1 has the feature of being able to protect a battery module or battery pack by detecting leaked electrolyte, the overall structure is very complicated, as it absorbs the electrolyte and senses whether current is flowing, etc. In particular, the electrolyte absorbing member must be separately attached to the outside of each battery cell, which requires multiple additional components and occupies space, resulting in a problem of low energy density.

[0016] Patent Document 2 relates to a battery module and a battery pack including the same, in which a film-type sensor for detecting electrolyte leakage is attached to both sides of a bus bar frame slit. The outside of the film-type sensor is provided with an insulating coating layer, which is a material that reacts with and dissolves in an organic solvent, i.e., the electrolyte.

[0017] In the case of Patent Document 2, when electrolyte leaks, the electrolyte moves to the lower end due to gravity, so unless a certain amount of electrolyte leaks, it is difficult to detect the leakage.In fact, there is a problem that the leaking electrolyte flows out between the slits, making early detection difficult.

[0018] Furthermore, electrical connections are required for each individual position where the sensor is attached, which requires a complex structure and can cause interference with the bus bar due to the electrical connections.

[0019] Patent Document 3 relates to a device for detecting electrolyte leakage in a battery module / pack, in which a conducting wire parallel to a strip containing a wiring portion is buried in the bottom of the battery module / pack, a wire window is formed to induce a capillary effect, and in the event of electrolyte leakage, both conducting wires are short-circuited, and the presence of battery leakage is determined by reading the electrical resistance.

[0020] In the case of Patent Document 3, the wiring for detecting the electrolyte is embedded in a separate bottom plate, but it can only detect when the amount of leaked electrolyte exceeds a predetermined amount. Patent Document 3 states that it can only detect when the amount of leaked electrolyte exceeds 8 ml.

[0021] Patent Document 3 is difficult to apply to battery modules or packs that use pouch-type batteries. Because the bottom of a pouch-type battery is connected without a separate seal, the only areas where electrolyte can leak are the sides or top. If electrolyte leaks to the top, the battery cells are stacked vertically, the gaps between them are very narrow, and pads may be provided between them. Therefore, unless the amount is large, the electrolyte that leaks to the top cannot flow to the bottom plate and dries before it reaches the bottom plate.

[0022] In Patent Document 3, the battery must be embedded separately in the bottom plate and must be provided with a capillary-like structure. If the battery is embedded longitudinally as in Patent Document 3, it is virtually impossible to detect leakage of the pouch-type battery at an early stage.

[0023] If electrolyte leaks from both sides of a pouch-type battery, i.e., from the protruding electrode tabs, it will leak down to the bottom end of the bus bar frame, and a considerable amount of leakage is required for it to flow to the separate bottom plate.

[0024] Patent Document 3 also mentions cases where the strip-shaped detection groove is located in the center of the bottom plate or along the battery electrodes in the battery module, directly below the electrodes, and mentions multiple cases. However, Patent Document 3 first limits the shape of the strip-shaped detection groove. In the case of a pouch-type battery, since both side electrodes must first be connected to the bus bar frame, the strip-shaped detection groove in Patent Document 3 can only be located below the bus bar frame. In this case, early detection of trace amounts is impossible. Patent Document 3 also limits the minimum detectable amount to more than 8 ml.

[0025] It can be seen that early detection is impossible for pouch-type batteries in either the examples of Patent Document 3 or when it is placed under the electrodes. Since Patent Document 3 describes that the strip-shaped detection grooves are arranged in the longitudinal direction, directly above the electrodes, or multiple grooves are arranged, this appears to be in consideration of the use of cylindrical battery cells.

[0026] As such, there has not yet been provided a technology that i) enables early detection of minute amounts of electrolyte leakage, ii) has a simple structure, and iii) can be applied without interfering with the configuration of conventional devices. [Prior art documents] [Patent documents]

[0027] [Patent Document 1] Korean Patent No. 10-1383599 [Patent Document 2] Korean Patent Publication No. 10-2021-0108269 [Patent Document 3] Chinese Patent Publication No. 111337201 Summary of the Invention [Problem to be solved by the invention]

[0028] The present invention has been made to solve the above problems, and aims to provide an electrolyte leakage detector and a battery module including the same, i) capable of detecting a small amount of electrolyte leakage early, ii) having a simple structure, and iii) being applicable without interfering with the configuration of a conventional device. [Means for solving the problem]

[0029] In order to solve the above problems, the present invention provides a battery module including a sensor that can detect electrolyte leaking from a battery cell, wherein the battery cell is a pouch-type battery, and the sensor is disposed at the lower end of a periphery of a vertical plate that includes a bus bar to which electrodes of the battery cell are electrically connected.

[0030] The vertical plate may include a plate-shaped vertical support portion to be vertically disposed, an electrode groove through which an electrode of a battery cell passes, the electrode groove having a slit shape formed by cutting a portion of the vertical support portion vertically, a bus bar electrically connected to the electrode of the battery cell passing through the electrode groove, and a lower end support portion having a horizontal band shape coupled along a lower periphery of the vertical support portion.

[0031] The sensing portion is disposed on the upper surface and / or the lower surface of the lower end support portion, and when the sensing portion is disposed on the lower surface of the lower end support portion, the lower end support portion may be provided with a groove communicating with the sensing portion.

[0032] The sensing unit has two insulated conductors, at least a portion of each of which is exposed to the outside. Examples of such conductors include, but are not limited to, a flexible flat cable (FFC) or a flexible printed circuit (FPC). For space saving and ease of installation, it is preferable to use conductors made of a thin or flexible material.

[0033] Meanwhile, the sensing unit may have two exposed conductive wires at positions where the electrodes of the battery cell are disposed, and one end of the sensing unit may be connected to a resistor.

[0034] A measuring unit may be included for measuring the resistance or voltage of the sensing unit.

[0035] The present invention also provides a method for detecting electrolyte leakage from a battery cell using a battery module, which includes measuring the resistance or voltage of the sensing unit and determining that electrolyte leakage has occurred if the measured resistance or voltage is outside a reference range.

[0036] Here, the leaked electrolyte can be detected if it is at least 1 / 20 ml.

[0037] The present invention can also be provided as a configuration in which the above-mentioned problems to be solved are arbitrarily combined. [Effects of the Invention]

[0038] As described above, the present invention provides an electrolyte leakage detector and a battery module including the same that i) can detect small amounts of electrolyte leakage early, ii) has a simple structure, and iii) can be applied without interfering with the configuration of a conventional device.

[0039] In particular, the present invention provides a very outstanding effect that cannot be achieved by conventional techniques, since it can immediately detect leakage of even a single drop of electrolyte, typically 1 / 20 ml. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is an exploded perspective view of a pouch-type battery according to the prior art. [Figure 2] FIG. 1 is an exploded perspective view schematically illustrating the structure of a battery module according to the prior art. [Figure 3] 1 is a perspective view of a battery cell mounted in a battery module according to an embodiment of the present invention; [Figure 4]10 is a diagram showing data on a portion where electrolyte leakage occurs in a battery module according to the present invention; FIG. [Figure 5] 2 is a schematic view of the inner side of the vertical plate of the battery module according to the present invention; FIG. [Figure 6] 2 is a schematic view of the outer side of the vertical plate of the battery module according to the present invention; FIG. [Figure 7] 1 is a schematic plan view of a sensing unit according to a first embodiment of the present invention; [Figure 8] 10 is a schematic diagram of an FPC as a sensing unit according to a second embodiment of the present invention; FIG. [Figure 9] 10 is a schematic view of the inner side of a vertical plate of a battery module according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing the results of measuring resistance values ​​depending on the amount of electrolyte. [Figure 11] FIG. 10 is a diagram showing the results of measuring resistance values ​​depending on the amount of electrolyte. DETAILED DESCRIPTION OF THE INVENTION

[0041] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of an embodiment of the present invention that will enable a person of ordinary skill in the art to easily carry out the present invention. However, in describing the operation principle of the preferred embodiment of the present invention in detail, if it is determined that a detailed description of related well-known functions or configurations may unnecessarily obscure the gist of the present invention, such detailed description will be omitted.

[0042] Furthermore, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected, coupled, or connected to another part, this includes not only when it is directly connected, coupled, or connected, but also when it is indirectly connected, coupled, or connected via another element in between. Furthermore, unless otherwise specified, "including a certain element" does not exclude other elements, but means that it may further include other elements.

[0043] Hereinafter, an electrolyte leakage detector and a battery module including the same according to the present invention will be described with reference to the accompanying drawings.

[0044] The basic structure of the battery module according to the present invention is similar to that of a conventional battery module using pouch-type batteries. FIG. 2 is an exploded perspective view schematically illustrating the structure of a battery module according to the prior art. Compared to the case of FIG. 2, the pouch-type battery may be modified to have electrodes disposed on only one side as shown in FIG. 1, and the bus bar frames 120 may not be connected to each other at their upper ends. Even in the case of a pouch-type battery with electrodes disposed on both sides, the configuration is not limited to the bus bar frame 120, and any configuration may be used as long as the bus bars on both sides are electrically connected. Furthermore, the monoframe and side frame 140 are merely examples, and any configuration may be used as long as they can function as an outer case surrounding the battery module.

[0045] FIG. 3 is a perspective view of a battery cell mounted in a battery module according to an embodiment of the present invention.

[0046] As shown in FIG. 3, a pouch-type battery or battery cell 60 includes an upper cell case 62, a lower cell case 61, electrode assemblies (not shown) housed inside the upper and lower cell cases, sealing portions 65 at the upper and lower ends of the cell case, a pair of electrode tabs (not shown), a pair of electrode leads consisting of a positive electrode lead 66 and a negative electrode lead 67 electrically connected to the electrode tabs on one side and protruding outside the cell case on the other side, and an insulating film (not shown).

[0047] In detail, the cell case upper part 62 and the cell case lower part 61 are provided with pocket-like spaces for accommodating the electrode assembly.

[0048] The cell case uses a laminate sheet consisting of an outer coating layer, a metal layer, and an inner coating layer to form a space capable of housing the electrode assembly.

[0049] The inner coating layer must have insulating and electrolytic resistance because it is in direct contact with the electrode assembly, and must also have sealing properties to seal against the outside, i.e., the sealing portions where the inner layers are thermally bonded together must have excellent adhesive strength.

[0050] The material for such an inner coating layer may be selected from polyolefin resins such as polypropylene, polyethylene, polyethylene acrylic acid, and polybutylene, which have excellent chemical resistance and sealing properties, polyurethane resins, and polyimide resins, but is not limited thereto. Polypropylene is preferred because of its excellent mechanical properties such as tensile strength, rigidity, surface hardness, and impact strength, as well as chemical resistance.

[0051] The metal layer in contact with the inner coating layer corresponds to a barrier layer that prevents moisture and various gases from penetrating into the battery from the outside, and a suitable material for such a metal layer is an aluminum thin film, which is lightweight yet has excellent formability.

[0052] The metal layer is provided on its outer surface with an outer coating layer, which may be made of a heat-resistant polymer having excellent tensile strength, moisture-proof properties, and air-proof properties to protect the electrode assembly and ensure heat resistance and chemical resistance, such as, but not limited to, nylon or polyethylene terephthalate.

[0053] The electrode assemblies housed inside the upper cell case 62 and the lower cell case 61 can be classified into a stack-type electrode assembly in which a plurality of electrodes are stacked; a jelly-roll-type electrode assembly in which a separator is interposed between a positive electrode and a negative electrode and the electrode is wound up; a lamination / stack-type electrode assembly in which a plurality of unit cells are stacked; and a stack / folding-type electrode assembly in which a unit cell is wound up with a separator sheet between them.

[0054] To manufacture the lamination / stack type electrode assembly or stack / folding type electrode assembly, a unit cell is prepared. The unit cell may be a mono-cell in which a separator is interposed between a positive electrode and a negative electrode, or a bi-cell in which a positive electrode, a negative electrode, and a positive electrode, or a negative electrode, a positive electrode, and a negative electrode, are stacked and a separator is interposed between the positive electrode and the negative electrode.

[0055] The electrode assembly according to the present invention may have a stacked structure of anode / separator / cathode / separator / anode. It goes without saying that the number of cathodes and anodes constituting the electrode assembly may be freely set. A lamination / stack type electrode assembly in which a plurality of unit cells are laminated may also be used. The electrode assembly structure may be applied to all electrode assemblies described herein.

[0056] The positive and negative electrodes of the electrode assembly are provided with a positive electrode tab and a negative electrode tab, respectively, and these paired tabs are connected to the positive electrode lead 66 and the negative electrode lead 67, respectively, by spot welding or the like, and are arranged to protrude to the outside of the cell case by a predetermined length.

[0057] The insulating films are located on the upper and lower surfaces of the pair of electrode leads, more specifically, at the sealing portion 65 where the cell case upper portion 62 and the cell case lower portion 61 are heat-sealed. The insulating films prevent electricity generated in the electrode assembly from flowing to the cell case via the electrode leads and maintain a sealed state between the electrode leads and the cell case. The insulating film is preferably made of a non-conductive material that does not conduct electricity well. Typically, insulating tape, which is easily attached to the electrode leads and has a relatively thin thickness, is used, but is not limited to this.

[0058] In the drawings, the battery cell is shown as being bidirectional, with the positive electrode lead 66 and the negative electrode lead 67 located at opposite ends, but the present invention can also be applied to a non-uniform battery cell in which the pair of electrode leads are arranged in the same direction.

[0059] During the use of a battery module, repeated charging and discharging can cause separation of the heat-sealed sealing portion of a pouch-type battery, i.e., deterioration of the heat-sealed portion due to expansion pressure caused by gas generated by an irreversible reaction or repeated use in an environment using high current such as rapid charging can lead to leakage of electrolyte.

[0060] In addition, electrolyte leakage can occur due to various reasons, such as the case being broken due to external impact or chemical corrosion.

[0061] Since the bottom surface of a pouch-type battery arranged vertically inside a battery module is connected without any separate sealing, the only areas where electrolyte can leak are the side or top surfaces of the pouch-type battery. If electrolyte leaks to the top surface, the battery cells are stacked vertically, the gaps between them are very narrow, and pads may be provided between them. Therefore, unless the amount is large, the electrolyte that leaks to the top surface cannot flow to the bottom plate and dries before it reaches the bottom plate.

[0062] If electrolyte leaks from both sides of a pouch-type battery, i.e., from the protruding electrode tabs, it will leak down to the bottom end of the bus bar frame, and a considerable amount of leakage is required for it to flow to the separate bottom plate.

[0063] The electrolyte solution according to the present invention is not limited to being aqueous or non-aqueous, as long as it is an electrolyte solution that can be used in secondary batteries. The non-aqueous electrolyte solution containing a lithium salt comprises an electrolyte solution and a lithium salt, and the electrolyte solution can be a non-aqueous organic solvent, an organic solid electrolyte, an inorganic solid electrolyte, or the like.

[0064] Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate (EC), butylene carbonate, dimethyl carbonate (DMC), diethylene carbonate (DEC), gamma-butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran (franc), 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate, and non-quantum organic solvents such as ethyl propionate.

[0065] Examples of the organic solid electrolyte that can be used include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, and polymerizing agents containing ionic dissociative groups.

[0066] Examples of the inorganic solid electrolyte that can be used include nitrides, halides, and sulfates of Li, such as LiN, LiI, LiNI, LiN-LiI-LiOH, LiSiO, LiSiO-LiI-LiOH, LiSiS, LiSiO, LiSiO-LiI-LiOH, and LiPO-LiS-SiS.

[0067] The lithium salt is a substance that is easily dissolved in the non-aqueous electrolyte, and examples thereof include LiCl, LiBr, LiI, LiClO4, LiBF4, and LiB 10 Cl 10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, (CF3SO2)2NLi, lithium chloroborane, lithium lower aliphatic carboxylic acids, lithium 4-phenylborate, imides, etc. can be used.

[0068] In addition, for the purpose of improving charge / discharge characteristics, flame retardancy, etc., the electrolyte may contain, for example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinoneimine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, aluminum trichloride, etc. In some cases, a halogen-containing solvent such as carbon tetrachloride or trifluoroethylene may be further added to impart non-flammability, and carbon dioxide may be further added to improve high-temperature storage properties, and fluoroethylene carbonate (FEC), propene sultone (PRS), etc. may also be further added.

[0069] A lithium salt-containing non-aqueous electrolyte can be produced by adding a lithium salt such as LiPF6, LiClO4, LiBF4, or LiN(SO2CF3)2 to a mixed solvent of a cyclic carbonate such as ethylene carbonate (EC) or propylene carbonate (PC), which is a solid dielectric solvent, and a linear carbonate such as diethyl carbonate (DEC), dimethyl carbonate (DMC), or ethylene methyl carbonate (EMC), which is a low-viscosity solvent.

[0070] Figure 4 shows the location where electrolyte leakage may occur in the battery module according to the present invention. It can be clearly seen from Figure 4 that in the case of a pouch-type battery, leakage may occur at the side sealing portion.

[0071] FIG. 5 is a schematic view of the inside of a vertical plate of a battery module according to the present invention, and FIG. 6 is a schematic view of the outside of a vertical plate of a battery module according to the present invention.

[0072] 5 and 6, vertical plates 200 are disposed on the left and right sides of the battery cell assembly in the battery module. Circuit portions including bus bars for electrical connection in the vertical plates 200 are omitted in FIGS.

[0073] The vertical plate 200 may include a vertically arranged plate-shaped vertical support portion 220, electrode grooves 240 having a plurality of slits formed by vertically cutting portions of the vertical support portion 220, through which the electrodes of the battery cells pass, bus bars (not shown) electrically connected to the electrodes of the battery cells passing through the electrode grooves 240, and a horizontal band-shaped lower end support portion 260 coupled along the lower periphery of the vertical support portion 220.

[0074] The sensing unit 265 according to the present invention is disposed on the upper and / or lower surface of the lower support unit 260. In Fig. 5, the sensing unit 265 is simplified and shown only by a black line. The sensing unit 265 is a measuring unit for measuring the resistance or voltage of the sensing unit 265, and may extend along the side of the vertical support unit 220 or be electrically connected to a measuring unit separately disposed along the side. The measuring unit may be included in the BMS of the battery module.

[0075] 7 is a schematic plan view of a sensing unit 265 according to a first embodiment of the present invention. The sensing unit 265 has two insulated conductors arranged therein, and has an exposed portion 267 where at least a portion of each of the two conductors is exposed to the outside.

[0076] The sensing unit 265 may have exposed portions 267 disposed at positions where the electrodes of the battery cells are disposed. In Figure 7, the distance between the exposed portions 267 is indicated by D. Since the thicknesses of the pouch-type batteries are the same or similar, when the pouch-type batteries are stacked horizontally after being vertically stood, the distance between the pouch-type batteries is also the same, and therefore the distance D between the exposed portions 267 may also be the same.

[0077] One end of the sensing section 265 may be connected by a resistor 269. Another part of the sensing section may be provided with a measuring section R that measures the resistance or voltage of the entire sensing section.

[0078] The resistance of the lead wire is very low, so when no electrolyte leaks, the resistance of the sensing part 265 corresponds to the resistance of the resistor 269. When the resistor 269 is not connected and the lead wire is not connected, the resistance corresponds to an infinite value.

[0079] 7, when electrolyte 270 leaks between two leads and this portion is exposed portion 267, the resistance at this time decreases by the amount of connection caused by the electrolyte. In either case, when resistor 269 is connected or when the leads are not connected, the decrease in resistance due to the leakage of electrolyte is so large that the resistance measured is essentially the resistance caused by the electrolyte.

[0080] As the number of parts connected by the electrolyte increases, the number of parallel connections also increases, and the resistance further decreases. The resistance decreased by these electrolytes is the same as the equation for the decrease in resistance due to parallel connections, calculated by adding up the reciprocals of the resistances and then taking the reciprocal of that sum.

[0081] When the sensing unit 265 is manufactured using a flexible flat cable (FFC) or a flexible printed circuit (FPC), it has the advantage of being not only thin but also flexible.

[0082] Fig. 8 is a schematic diagram of a flexible printed circuit (FPC) which is a sensing unit 465 according to a second embodiment of the present invention. Fig. 8 is a schematic diagram of the upper surface of the sensing unit 465 where the exposed portion 467 is exposed. Figs. 7 and 8 show only one example of the sensing unit, and it is possible to configure an exposed portion where two insulated conductive wires are arranged and at least a portion of each of the two conductive wires is exposed to the outside, and the specific shape can be modified into various shapes.

[0083] The sensing unit 465 has repeated exposed portions 467 that are exposed to the outside. Thin film copper patterns 466, as shown in the upper right corner of Figure 8, are repeatedly connected and arranged, and a portion of each is exposed to the outside to form the exposed portion 467. The thin film copper patterns 466, except for the exposed portion 467, are insulated by an FPC cover layer 468, which is an insulating material.

[0084] 9 is a schematic diagram of the inside of a vertical plate of a battery module according to a third embodiment of the present invention. The vertical plate 300 includes a vertically disposed, plate-like vertical support member 320, electrode grooves 340 formed by vertically cutting portions of the vertical support member 320 to form a plurality of slits through which the electrodes of the battery cells pass, bus bars (not shown) electrically connected to the electrodes of the battery cells passing through the electrode grooves 340, and a horizontal band-shaped lower support member 360 coupled along the lower periphery of the vertical support member 320.

[0085] The sensing unit 365 according to the present invention may be disposed on the lower surface of the lower support part 360. In Fig. 9, the sensing unit 365 is indicated by a dotted line because it is located on the lower surface of the lower support part 360. In addition, the sensing unit 365 may be electrically connected to a measuring unit for measuring the resistance or voltage of the sensing unit 365, and the measuring unit may extend along the side of the vertical support part 320 or may be separately disposed along the side. The measuring unit may be included in the BMS of the battery module.

[0086] When the sensing unit 365 is disposed on the lower surface of the lower support part 360, the lower support part 360 may be provided with a groove 366 that can communicate with the sensing unit 365. The groove 366 is preferably located at a position where an electrode of a pouch-type battery is disposed. The cross section of the groove 366 that passes through the lower support part 360 and communicates with the sensing unit 365 may have the same size at the top and bottom, or may become larger or smaller from the top to the bottom.

[0087] The present invention also provides a method for detecting electrolyte leakage from a battery cell using a battery module, which measures the resistance or voltage of a sensing unit and determines that electrolyte leakage has occurred if the measured resistance or voltage is outside a reference range.

[0088] 10 and 11 show the results of measuring the resistance value depending on the amount of electrolyte.

[0089] <Experiment 1> The resistance due to electrolyte exposure was measured using the sensing element according to the second embodiment of Figure 8. The cover layer of the flexible printed circuit (FPC) was polyimide (PI) or polyethylene naphthalate (PEN). The sensing element had five exposed areas. A separate sensing element was used for each electrolyte. The electrolyte used was based on ethylene carbonate (EC), a solid dielectric solvent, and ethylene methyl carbonate (EMC), a low-viscosity solvent, with additional additives.

[0090] In Figures 10 and 11, the two data points on the left, the thin solid line and the thick dotted line, are for a polyimide cover layer, and the two data points on the right, the thick solid line and the thin dotted line, are for a polyethylene naphthalate cover layer. The y-axis is the measured resistance in MOhm, and the x-axis is time in seconds. Experiments were conducted with a small time lag between each test to observe the data.

[0091] The upper graph in Figure 10 shows that the resistance is maintained at approximately 10 MOhm before exposure to the electrolyte. The lower graph in Figure 10 shows that when one drop (approximately 1 / 20 ml) of electrolyte is dropped onto one exposed portion 467, the resistance instantly drops to 0.07 MΩ or less. When one drop (approximately 1 / 20 ml) of electrolyte is dropped onto each of the five exposed portions in turn, the resistance gradually decreases, eventually dropping to 0.03 MOhm or less.

[0092] It is clear that the sensing unit according to the present invention is very sensitive and can sense a small amount of electrolyte, and that even in the case of a small amount of electrolyte, the amount of leakage can be quantitatively determined.

[0093] <Experiment 2> As in Experiment 1, the five exposed sensing elements were immersed in approximately 250 ml of tap water (immersion) and the resistance was measured. The results showed a drop to 0.1 MΩ (500 seconds on the x-axis in Figure 11). The thin solid and thick dotted lines, as well as the thick solid and thin dotted lines, are the same as in Figure 10. An additional 1 ml of electrolyte, equivalent to approximately 20 drops, was then dripped onto the sensing elements. In this case, the resistance also dropped to below 0.03 MΩ (see 600-900 seconds in Figure 11). After 10 minutes, the resistance increased to above 0.07 MΩ (see 1200 seconds in Figure 11). After this, 1 ml of electrolyte was dripped over time until the total amount was 2 ml, 3 ml, and 4 ml. The resistance decreased each time the total amount increased to 2 ml, 3 ml, and 4 ml. When the amount of electrolyte leakage was greater than 4 ml, the resistance did not increase even after a long time.

[0094] From Experiments 1 and 2, it can be seen that the sensor according to the present invention has an excellent effect of being able to clearly detect even a small amount of electrolyte leakage. It can also quantitatively distinguish the amount of leakage. Meanwhile, in the case of water immersion, it can also distinguish whether the problem is due to water immersion or electrolyte.

[0095] The above experiments demonstrate that the present invention is capable of quickly detecting even minute amounts of electrolyte, and is also capable of distinguishing and identifying cases where leakage occurs at multiple locations.

[0096] Although certain parts of the present invention have been described in detail above, it will be apparent to those skilled in the art that such specific descriptions are merely preferred embodiments and do not limit the scope of the present invention. It is obvious to those skilled in the art that various changes and modifications are possible within the scope and technical spirit of the present invention, and it goes without saying that such changes and modifications fall within the scope of the appended claims. [Explanation of symbols]

[0097] 10 Battery case 11, 61 bottom 12, 62 upper 13 Storage section 20 Electrode assembly 21, 22 Electrode tabs 31, 32, 66, 67 Electrode leads 41, 42 Insulating film 50, 60 pouch type batteries 65 Sealing part 100 Battery Module 110 Cell Assembly 111 Pouch-type battery 112 Electrode Lead 120 Busbar Frame 121, 122, 200 vertical plate 123 Upper Plate 126 Busbar 130 Monoframe 140 Side Frame 200, 300 vertical plate 220, 320 vertical support 240, 340 electrode groove 260, 360 Lower end support part 265, 365, 465 sensing section 366 Groove 466 Thin Film Copper Pattern 267, 467 Exposed part 468 FPC cover layer 269 ​​Resistance 270 Electrolyte D Spacing between exposed areas R measurement part

Claims

1. A battery module including a sensor capable of detecting electrolyte leaking from a battery cell, the battery cell is a pouch-type battery; A plurality of the battery cells are stacked to form a battery cell assembly, The sensing unit is disposed at the lower end of the periphery of a vertical plate including a bus bar to which the electrodes of the battery cells are electrically coupled, and the sensing unit has a configuration in which the sensing unit is two insulated conductors that extend in the stacking direction of the battery cells, with at least a portion of each of the two conductors exposed to the outside, and detects the electrolyte that has leaked from the battery cell in response to a change in resistance or voltage between the two conductors.

2. The vertical plate is a plate-shaped vertical support portion to be vertically disposed; an electrode groove through which an electrode of the battery cell passes, the electrode groove having a plurality of slits formed by cutting a portion of the vertical support part vertically; a bus bar electrically connected to the electrode of the battery cell that has passed through the electrode groove; a lower end support portion having a horizontal band shape and connected along a lower periphery of the vertical support portion; The battery module of claim 1 , comprising:

3. The battery module according to claim 2 , wherein the sensing portion is disposed on an upper surface and / or a lower surface of the lower end support portion.

4. The battery module according to claim 3 , wherein when the sensing portion is disposed on the lower surface of the lower end support portion, the lower end support portion is provided with a groove communicating with the sensing portion.

5. The battery module of claim 4 , wherein the sensing unit includes a flexible flat cable (FFC) or a flexible printed circuit (FPC).

6. The battery module according to claim 1 , wherein the sensing unit has two conductive wires exposed to the outside at positions where the electrodes of the battery cells are disposed.

7. The battery module of claim 1 , wherein one end of the sensing unit is connected by a resistor.

8. The battery module according to claim 1 , further comprising a measuring unit for measuring the resistance or voltage of the sensing unit.

9. A method for detecting electrolyte leakage from a battery cell using the battery module according to any one of claims 1 to 8, comprising: The method for detecting electrolyte comprises measuring the resistance or voltage of the sensing part, and determining that electrolyte has leaked if the measured resistance or voltage is outside a reference range.

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