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 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 then connecting these battery modules to form a battery pack.

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

[0004] A pouch-type battery is generally manufactured by forming a laminate sheet including an outer coating layer, a metal barrier layer, and an inner adhesive layer into a battery case, and then sealing the laminate sheet to manufacture the pouch-type battery.

[0005] 1, in a pouch-type battery 50, an electrode assembly 20 is incorporated in a receiving portion 13 of a battery case 10 composed of a pouch-type lower portion 11 and a pouch-type upper portion 12. In the electrode assembly 20, a positive electrode tab and a negative electrode tab 21, 22 are welded to two electrode leads 31, 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, 42 interposed between the upper and lower portions of the electrode leads 31, 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. When the positive and negative electrode tabs 21, 22 are positioned in different directions on the electrode assembly 20, that is, when 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 positioned on the y-axis in FIG. 1, rotates counterclockwise to be positioned on a plane positioned 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 having a positive electrode tab and a negative electrode tab on one side, and bus bars are disposed on both ends of the battery cell assembly to electrically connect the positive electrode tab and the negative electrode tab, more specifically, the positive electrode lead and the negative electrode lead. 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 showing a schematic structure of a battery module 100 according to the related art. Referring to FIG. 2, the battery module 100 includes a battery cell assembly 110 formed by stacking battery cells 111 in which electrode leads 112 are arranged on both sides, a bus bar frame 120 including a first vertical plate 121 and a second vertical plate 122 respectively arranged 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 arranged on the upper part of the battery cell assembly 110, and a monoframe 130 formed in a square tube shape such that the battery cell assembly 110 to which the bus bar frame 120 is attached is inserted and arranged in an internal space. A side frame 140 is coupled to the monoframe to complete the battery module 100.

[0009] The busbars 126 are disposed on the first vertical plate 121 and the second vertical plate 122. The busbars 126 are for connecting the plurality of battery cells 111 in series or in parallel. The busbars 126 are conductors having low impedance and high current capacity, and the plurality of busbars 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, the bus bar 126 is not limited to this 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 configure a battery module or battery pack. After multiple cylindrical or prismatic batteries are vertically arranged, bus bars can be placed on the upper and / or lower surfaces on which the electrodes are arranged.

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

[0013] When pouch-type batteries, cylindrical batteries, and prismatic batteries are used in a battery module or battery pack, leakage of electrolyte from inside the battery cells can cause various problems. If electrolyte leaks, not only the electrical performance of the battery module or battery pack will be reduced, but there is also a risk of corrosion, short circuit, and fire due to the leaked electrolyte. In the case of a battery module containing many battery cells, it is very important to detect these problems early due to safety issues.

[0014] Patent Document 1 relates to an apparatus and method for detecting leakage of electrolyte from a battery cell to protect a battery pack. Patent Document 1 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 electrolyte absorption, a power supply unit 20 connected to both ends of the electrolyte absorbing member and applying power, a resistance unit 30 connected between the electrolyte absorbing member and the power supply unit, a sensing unit 40 for sensing whether a current flows through the resistance unit, and a control unit 50 for cutting off a charge / discharge current by melting a fuse on a charge / discharge path of the battery pack when the sensing unit detects that a current flows through the resistance unit.

[0015] Although Patent Document 1 has the feature of being able to protect a battery module or a battery pack by detecting leaked electrolyte, the overall structure is very complicated, as it absorbs electrolyte and senses whether current flows, etc. In particular, the electrolyte absorbing member must be separately attached to the outside of each battery cell, and multiple members are required to occupy space, which results 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 leakage of electrolyte 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 the 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 of the electrolyte. Rather, there is a problem that the leaking electrolyte flows out between the slits, making early detection difficult.

[0018] In addition, 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 conductor parallel to a strip including a wiring portion is buried in the bottom of the battery module / pack, and a wire window is formed to induce a capillary effect, which shorts both conductors in the event of electrolyte leakage, and the presence of battery leakage is determined by reading the electrical resistance.

[0020] In the case of Patent Document 3, the wiring section for detecting the electrolyte is embedded in a separate bottom plate, but detection is possible only when the amount of leaked electrolyte is equal to or greater than a predetermined amount. Patent Document 3 states that detection is possible only when the amount of leaked electrolyte exceeds 8 ml.

[0021] In the case of a battery module or pack using a pouch-type battery, it is difficult to apply Patent Document 3. Since the bottom surface of a pouch-type battery is a part that is connected without a separate seal, the only part where electrolyte can leak is the side or top surface. If electrolyte leaks to the top surface, the battery cells are stacked vertically, the gap between them is very narrow, and there may be a pad between them, so the electrolyte that leaks to the top surface cannot flow to the bottom plate unless it is a large amount, and dries before it reaches the bottom plate.

[0022] In the case of 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 in the longitudinal direction as in Patent Document 3, it is practically 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 portions where the electrode tabs protrude, it leaks to the lower end of the bus bar frame, and a significant amount of electrolyte must leak in order for it to flow to the separate bottom plate.

[0024] Patent Document 3 also mentions a case where the strip-shaped detection groove is provided in the center of the bottom plate or arranged along the battery electrode in the battery module and located directly below the electrode, 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 coupled to the bus bar frame, the strip-shaped detection groove of Patent Document 3 can only be present at the bottom of the bus bar frame. In this case, it is impossible to detect trace amounts early. Patent Document 3 also limits the minimum detectable amount to more than 8 ml.

[0025] For pouch-type batteries, it is clear that early detection is impossible in either the example of Patent Document 3 or when it is placed under the electrode. Since Patent Document 3 describes that the strip-shaped detection groove is placed in the longitudinal direction, directly above the electrode, or multiple electrodes are placed, this appears to be in consideration of the use of cylindrical battery cells.

[0026] Thus, there has yet to be provided a technology that i) enables early detection of minute 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] China 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 minute amounts of electrolyte leakage at an early stage, 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 capable of detecting electrolyte leaked from a battery cell, in which the battery cell is a pouch-type battery, and the sensor is disposed at a lower end of a periphery of a vertical plate including a bus bar to which electrodes of the battery cell are electrically coupled.

[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 into a number of vertical directions, 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 an upper surface and / or a 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 arranged thereon, 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 conductive wires exposed to the outside at a position 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 portion may be included for measuring the resistance or voltage of the sensing portion.

[0035] The present invention also provides a method for detecting electrolyte leakage from a battery cell using a battery module, comprising measuring the resistance or voltage of the sensing unit and determining that electrolyte has leaked 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. Effect of the Invention

[0038] As described above, the present invention provides an electrolyte leakage detector and a battery module including the same, which i) can detect minute 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 provided by the conventional technology since it can immediately detect leakage of even a single drop of electrolyte, usually 1 / 20 ml. [Brief description of the drawings]

[0040] [Figure 1] FIG. 1 is an exploded perspective view of a pouch-type battery according to the prior art. [Diagram 2] FIG. 1 is an exploded perspective view showing a schematic structure of a battery module according to the prior art; [Diagram 3] 2 is a perspective view of a battery cell mounted in a battery module according to an embodiment of the present invention; FIG. [Figure 4]FIG. 13 is a diagram showing data on a portion where electrolyte leakage occurs in a battery module according to the present invention. [Diagram 5] FIG. 2 is a schematic view of the inside of a vertical plate of a battery module according to the present invention. [Figure 6] FIG. 2 is a schematic view of the outer side of a vertical plate of a battery module according to the present invention. [Figure 7] 1 is a schematic plan view of a sensing unit according to a first embodiment of the present invention; [Figure 8] FIG. 11 is a schematic diagram of an FPC which is a sensing unit according to a second embodiment of the present invention. [Figure 9] FIG. 11 is a schematic view showing the inner side of a vertical plate of a battery module according to a third embodiment of the present invention. [Figure 10] FIG. 13 is a diagram showing the results of measuring resistance values ​​according to the amount of electrolyte. [Figure 11] FIG. 13 is a diagram showing the results of measuring resistance values ​​according to the amount of electrolyte. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0042] In addition, 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 the case where the part is directly connected, coupled, or connected, but also the case where the part is indirectly connected, coupled, or connected via another element in between. In addition, the term "including a certain component" does not mean to exclude other components, but means that other components may be further included, unless otherwise specified.

[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 the same as that of a conventional battery module using a pouch-type battery. FIG. 2 is an exploded perspective view that shows a schematic structure of a battery module according to the prior art. Compared to the case of FIG. 2, the pouch-type battery can be modified to a form in which electrodes are arranged on only one side as shown in FIG. 1, and the upper ends of the bus bar frames 120 do not need to be connected to each other. Even in the case of a pouch-type battery in which electrodes are arranged on both sides, the form is not limited to the form of the bus bar frame 120, and any form can be applied as long as the bus bars on both sides are electrically connected. In addition, the mono frame and the side frame 140 are merely examples, and any form can be used as long as it can play the role of an external 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, an electrode assembly (not shown) housed inside the upper and lower cell case, 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 since 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] Materials 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 good sealing properties, polyurethane resins, and polyimide resins, but are not limited thereto. Polypropylene is preferred, which has 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 internal coating layer corresponds to a barrier layer that prevents moisture and various gases from penetrating into the inside of 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 permeability, and air permeability so as to protect the electrode assembly and ensure heat resistance and chemical resistance. Examples of the outer coating layer include, but are not limited to, nylon or polyethylene terephthalate.

[0053] The electrode assemblies housed inside the cell case upper part 62 and the cell case lower part 6l 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 positioned on a separator sheet and the electrode is wound up.

[0054] To manufacture the lamination / stack type electrode assembly or stack / folding type electrode assembly, a unit cell is manufactured. 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 structure in which anode / separator / cathode / separator / anode are stacked. In addition, it goes without saying that the number of cathodes and anodes constituting the electrode assembly may be freely set and used. Also, a lamination / stack type electrode assembly in which a plurality of unit cells are laminated may be used. The electrode assembly structure may be applied to all electrode assemblies described in this specification.

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

[0057] The insulating film is located on the upper and lower surfaces of the pair of electrode leads, more specifically, on a sealing portion 65 where the cell case upper portion 62 and the cell case lower portion 61 are heat-sealed. The insulating film prevents electricity generated in the electrode assembly from flowing to the cell case via the electrode leads and maintains 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, and generally, insulating tape that is easy to attach to the electrode leads and has a relatively thin thickness is often used, but is not limited to this.

[0058] In the drawings, a bidirectional battery cell is shown in which the positive electrode lead 66 and the negative electrode lead 67 are located at both 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 the battery module, the heat-sealed sealing part of the pouch-type battery may separate due to repeated charging and discharging, i.e., the heat-sealed part may deteriorate due to expansion pressure caused by gas generated by an irreversible reaction or repeated use of a high current such as rapid charging, resulting in leakage of electrolyte.

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

[0061] Since the bottom surface of the pouch-type battery arranged vertically inside the battery module is a part connected without a separate seal, the only part that can leak electrolyte is the side or top surface of the pouch-type battery. If electrolyte leaks to the top surface, the battery cells are stacked vertically, the gap between them is very narrow, and in some cases a pad is provided between them, so that the electrolyte leaking to the top surface cannot flow to the bottom plate unless it is a large amount, and dries before it reaches the bottom plate.

[0062] If electrolyte leaks from both sides of a pouch-type battery, i.e., from the portions where the electrode tabs protrude, it leaks to the lower end of the bus bar frame, and a significant amount of electrolyte must leak in order for it to flow to the separate bottom plate.

[0063] The electrolyte according to the present invention is not limited to being aqueous or non-aqueous as long as it is an electrolyte that can be used in secondary batteries. The non-aqueous electrolyte containing a lithium salt is composed of an electrolyte and a lithium salt, and the electrolyte is 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 non-quantum organic solvents such as 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, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate, and ethyl propionate.

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

[0066] As the inorganic solid electrolyte, for example, nitrides, halides, and sulfates of Li such as Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, and Li3PO4-Li2S-SiS2 can be used.

[0067] The lithium salt is a substance that is easily dissolved in the non-aqueous electrolyte, and examples of the lithium salt 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 carboxylates, 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, in order to impart non-flammability, a halogen-containing solvent such as carbon tetrachloride or trifluoroethylene may be further contained, and in order to improve high-temperature storage characteristics, carbon dioxide may be further contained, and fluoro-ethylene carbonate (FEC), propene sultone (PRS), etc. may be further contained.

[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] 4 is a data showing a portion where electrolyte leakage may occur in the battery module according to the present invention. Referring to FIG. 4, it can be clearly seen that in the case of a pouch-type battery, the portion where electrolyte leakage may occur is 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. 5 and 6.

[0073] The vertical plate 200 may include a vertically arranged plate-like vertical support portion 220, a portion of the vertical support portion 220 having a plurality of slits cut vertically to form electrode grooves 240 through which electrodes of battery cells pass, a bus bar (not shown, omitted) electrically connected to the electrodes of the battery cells passing through the electrode grooves 240, and a lower end support portion 260 having a horizontal band shape and coupled along the lower edge 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 end support part 260. In Fig. 5, the sensing unit 265 is simplified and shown only by a black line. Also, 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 part 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 an exposed portion 267 in which two insulated conductors are arranged and at least a portion of each of the two conductors is exposed to the outside.

[0076] The sensing unit 265 may have an exposed portion 267 disposed at a position where an electrode of the battery cell is disposed. In Fig. 7, the distance between the exposed portions 267 is indicated as D. Since the pouch-type batteries have the same or similar thickness, when the pouch-type batteries are vertically stood and then stacked horizontally, 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 portion 265 may be connected by a resistor 269. Another portion of the sensing portion may be provided with a measuring portion R that measures the resistance or voltage of the entire sensing portion.

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

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

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

[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 board (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 as long as two insulated conductive wires are arranged and at least a part of each of the two conductive wires is exposed to the outside to form an exposed portion, and the specific shape can be modified into various shapes.

[0083] The sensing unit 465 has repeatedly arranged exposed portions 467 that are exposed to the outside. Thin film copper patterns 466, as shown in the upper right corner of Fig. 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 arranged plate-like vertical support part 320, electrode grooves 340 having a plurality of slits formed by cutting a part of the vertical support part 320 vertically and through which the electrodes of the battery cells pass, bus bars (not shown, omitted) electrically connected to the electrodes of the battery cells passing through the electrode grooves 340, and a lower end support part 360 having a horizontal band shape coupled along the lower periphery of the vertical support part 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 since 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 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 capable of communicating 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 which 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 has leaked if the measured resistance or voltage is outside a reference range.

[0088] 10 and 11 show the results of measuring the resistance value according to 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 FIG. 8. The cover layer of the flexible printed circuit board (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. The experiments were conducted with a small time lag between each for data observation.

[0091] Looking at the upper graph of Figure 10, it can be seen that the resistance is maintained at about 10 MOhm before exposure to the electrolyte. Looking at the lower graph of Figure 10, it can be seen that when one drop of electrolyte (about 1 / 20 ml) is dripped onto one exposed portion 467, the resistance instantly drops to 0.07 MΩ or less. When one drop of electrolyte (about 1 / 20 ml) is dripped onto each of the five exposed portions in sequence, it can be seen that the resistance decreases sequentially, eventually dropping to 0.03 MOhm or less.

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

[0093] <Experiment 2> As in Experiment 1, the sensing element having five exposed parts was immersed in about 250 ml of tap water (immersion) and the resistance was measured, and it was found to drop to 0.1 MΩ (time 500 seconds on the x-axis in FIG. 11). The thin solid line, thick dotted line, and thick solid line and thin dotted line are the same as in FIG. 10. An additional 1 ml of electrolyte, equivalent to about 20 drops, was dripped onto the electrodes. In this case, too, it was found that all resistances dropped to 0.03 MOhm or less (see 600 to 900 seconds in FIG. 11). After 10 minutes had passed, the resistances all increased to 0.07 MOhm or more (see 1200 seconds in FIG. 11). After this, 1 ml of electrolyte was dripped over time until the total amount was 2 ml, 3 ml, and 4 ml. Each time the total amount increased to 2 ml, 3 ml, and 4 ml, the resistance decreased. When the amount of electrolyte leakage was 4 ml or more, the resistance did not increase even after a long period of time.

[0094] From Experiment 1 and Experiment 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. Also, the amount of leakage can be quantitatively classified. Meanwhile, in the case of immersion in water, it can be distinguished whether the problem is due to water immersion or electrolyte.

[0095] From the above experiments, it can be seen that the present invention is capable of quickly detecting even a very small amount of electrolyte, and is also capable of distinguishing and grasping cases where leakage occurs at multiple locations.

[0096] Although certain parts of the present invention have been described in detail above, those having ordinary skill in the art will understand that such specific descriptions are merely preferred embodiments and do not limit the scope of the present invention. It will be apparent 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 Lower 12, 62 Upper 13 Storage unit 20 Electrode assembly 21, 22 Electrode tabs 31, 32, 66, 67 Electrode leads 41, 42 Insulating film 50, 60 Pouch type battery 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 Board 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 parts R measurement section

Claims

1. A battery module including a sensor capable of detecting electrolyte leakage from a battery cell, the battery cell is a pouch-type battery, A battery module, wherein the sensing portion is disposed at a lower end around a periphery of a vertical plate including a bus bar to which the electrodes of the battery cells are electrically coupled.

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 in a vertical direction; a bus bar electrically connected to the electrode of the battery cell that has passed through the electrode groove; a lower end support portion connected along a lower periphery of the vertical support portion and having a horizontal band shape; The battery module of claim 1 .

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 a 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 according to claim 1 , wherein the sensing unit has two insulated conductors, at least a portion of each of the two conductors being exposed to the outside.

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

7. The battery module according to claim 5 , wherein the sensing unit has two conductive wires exposed to the outside at positions where the electrodes of the battery cells are disposed.

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

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

10. A method for detecting electrolyte leakage from a battery cell using the battery module according to any one of claims 1 to 9, comprising the steps of: 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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