Battery module and battery pack comprising same

Abstract

A battery module according to the present invention comprises: battery cells: a module case accommodating the battery cells therein and having a drainage port for draining an electrolyte leaking from the battery cells; and an electrolyte discharge control device configured to shield the drainage port, and to, when the electrolyte level rises inside the module case, open the drainage port for a predetermined time and then shield the drainage port.

Description

Battery module and battery pack including same

[0001] The present invention relates to a battery module and a battery pack including the same, and more particularly, to a battery module having an electrolyte discharge control device capable of preventing a risk of short circuit between battery cells due to electrolyte being ejected into the battery cells when a thermal event occurs, and a battery pack including the same.

[0002] This application claims priority to Korean Patent Application No. 10-2024-0042014, filed on March 27, 2024, and all contents disclosed in the specification and drawings of the said application are incorporated by reference into this application.

[0003] With the rapid growth in technological development and demand for various mobile devices, electric vehicles, and energy storage systems (ESS), interest in and demand for secondary batteries as an energy source are rapidly increasing. While nickel-cadmium and nickel-metal hydride batteries were previously widely used as secondary batteries, lithium secondary batteries are increasingly being used due to their virtually zero memory effect compared to nickel-based batteries, allowing for easy charging and discharging, extremely low self-discharge rates, and high energy density.

[0004] These lithium secondary batteries primarily use lithium oxide and carbon materials as the positive and negative electrode active materials, respectively. Lithium secondary batteries comprise an electrode assembly comprising positive and negative plates coated with the positive and negative electrode active materials, respectively, with a separator interposed between them, and an outer case, i.e., a battery case, that seals and encloses the electrode assembly together with an electrolyte.

[0005] In general, secondary batteries can be classified into can-type batteries in which the electrode assembly is built into a metal can and pouch-type batteries in which the electrode assembly is built into a pouch of an aluminum laminate sheet, depending on the shape of the outer packaging material.

[0006] Lithium secondary batteries, widely used today, have an operating voltage of approximately 2.5 V to 4.5 V per battery. Therefore, for electric vehicles or power storage devices requiring large capacity and high output, multiple lithium secondary batteries are connected in series and / or parallel to form battery modules or battery packs, which are then used as an energy source. To meet the output and capacity requirements of electric vehicles, battery modules or battery packs typically contain a significant number of lithium secondary batteries.

[0007] Meanwhile, if overcharging occurs during the charging and discharging process of a secondary battery cell or an internal short circuit occurs due to some factor, the temperature may rise and gas may be generated through a chemical reaction. This may cause the secondary battery cell to swell, and if this worsens, the sealing of the battery case may be broken, causing electrode particles and electrolyte to be discharged. If the electrolyte fills the inside of the battery module to a certain height and, for example, the bus bars (3) are submerged in the electrolyte (W), a short circuit between the secondary battery cells may occur, causing the secondary battery cells to ignite or explode in a chain reaction. Therefore, conventional battery modules often have a drain hole (O) to drain the electrolyte to the outside.

[0008] However, as illustrated in Fig. 1, in the case of a battery pack assembled using the above battery modules, when a thermal event occurs in a battery module (1), the electrolyte (W) flowing out from the battery module (1) may flow into the interior of the other battery module (2) through the drain of the other battery module (2). In this case, current flow or short circuit may be caused between the two battery modules (1, 2) or an electrical problem may occur in the other battery module (2).

[0009] The present invention was created in consideration of the above-described problems, and its purpose is to provide a battery module configured to discharge electrolyte so that the level of electrolyte in the module case does not exceed a certain height when a thermal event occurs in the battery module, or to prevent electrolyte from flowing back into the inside from the outside, and a battery pack including the battery module.

[0010] The technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0011] According to one aspect of the present invention, a battery module may be provided, comprising: battery cells; a module case accommodating the battery cells therein and having a drain for draining electrolyte leaking from the battery cells; and an electrolyte discharge control device configured to block the drain, and when the electrolyte level inside the module case rises, open the drain for a predetermined period of time and then block the drain.

[0012] The above electrolyte discharge control device includes a storage tank coupled to the module case; a first blocking film covering the drain port and forming one side of the storage tank; a second blocking film spaced apart from the first blocking film and forming the other side of the storage tank; a block support film disposed in a block insertion hole formed penetrating an upper portion of the storage tank; and a blocking block disposed on the upper portion of the storage tank with a lower end supported by the block support film, and provided to close a flow path between the first blocking film and the second blocking film provided inside the storage tank when the block support film is lost due to the electrolyte, wherein the first blocking film, the second blocking film, and the block support film may be composed of a material that can be dissolved and lost in the electrolyte.

[0013] The first and second blocking films may include a first region and a second region having different thicknesses, and the first region may be formed to have a thickness smaller than that of the second region and may be provided at a lower position than the second region.

[0014] The first region may be configured to have a thickness of 100 um to 150 um, and the second region may be configured to have a thickness of 300 um or more.

[0015] The above block support film may be configured to have a thickness greater than the thickness of the first region.

[0016] The above blocking block can be made of an insulating material.

[0017] The first blocking film, the second blocking film, and the block support film may be made of at least one material selected from the group consisting of epoxy, water-soluble pulp, and bioplastic.

[0018] The above electrolyte discharge control device may include a block slot concavely formed in the lower part of the storage tank so that the lower part of the blocking block can be inserted.

[0019] The above electrolyte discharge control device may include an actuator provided to lift the blocking block upward on the lower part of the storage tank; a level detection unit that detects the level of the electrolyte inside the module case; and a control unit that controls the actuator to operate based on a signal transmitted from the level detection unit.

[0020] The above water level detection unit may include a first conductor and a second conductor that are horizontally spaced apart from the bottom surface of the module case at a predetermined height; and a current detection unit that detects a current flowing between the first conductor and the second conductor when an electrolyte comes into contact with the first conductor and the second conductor.

[0021] A busbar frame assembly including a plurality of busbars electrically connecting the battery cells and a busbar frame supporting the plurality of busbars; and an end cover covering the busbar frame assembly, wherein the drain hole may be provided at a lower portion of the end cover.

[0022] The above electrolyte discharge control device may be detachably provided at the lower part of the end cover.

[0023] According to another aspect of the present invention, a battery pack including one or more of the above-described battery modules can be provided.

[0024] According to the present invention, a battery module including an electrolyte discharge control device that discharges electrolyte so that the level of electrolyte in a module case does not exceed a certain height when a thermal event occurs in the battery module or prevents electrolyte from flowing back into the module from the outside, and a battery pack including the battery module can be provided.

[0025] In addition, the present invention may have various other effects, which will be described in each embodiment configuration, or an explanation of effects that can be easily inferred by a person skilled in the art will be omitted.

[0026] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0027] Figure 1 is a drawing exemplarily showing the electrolyte immersion situation of battery modules according to the prior art.

[0028] Figure 2 is a schematic perspective view of a battery module according to one embodiment of the present invention.

[0029] Figure 3 is a schematic exploded perspective view of the battery module of Figure 2.

[0030] Figure 4 is a schematic cross-sectional view of an electrolyte discharge control device according to one embodiment of the present invention.

[0031] FIG. 5 is a drawing showing a state in which a drain is blocked by an electrolyte discharge control device according to one embodiment of the present invention.

[0032] Fig. 6 is a drawing showing a state in which the first blocking film is lost in the electrolyte discharge control device of Fig. 5.

[0033] Fig. 7 is a drawing showing a state in which the second blocking film is lost in the electrolyte discharge control device of Fig. 6.

[0034] Figure 8 is a drawing showing a state in which the support film is lost and the blocking block falls in the electrolyte discharge control device of Figure 7.

[0035] FIGS. 9 and 10 are reference drawings for explaining an operation example of an electrolyte discharge control device including a water level detection unit as a battery module according to another embodiment of the present invention.

[0036] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Terms or words used in this specification and claims should not be interpreted as limited to their conventional or dictionary meanings, but should be interpreted with meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to best explain his or her own invention. Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical idea of ​​the present invention, and various equivalents and modified examples may exist as of the time of this application.

[0037] In the drawings, the sizes of each component or specific parts of that component are exaggerated, omitted, or schematically illustrated for convenience and clarity of explanation. Therefore, the size of each component does not entirely reflect its actual size. If a detailed description of a related known function or configuration is deemed to unnecessarily obscure the gist of the present invention, such description will be omitted.

[0038] FIG. 2 is a schematic perspective view of a battery module according to one embodiment of the present invention, FIG. 3 is a schematic exploded perspective view of the battery module of FIG. 2, and FIG. 4 is a schematic cross-sectional view of an electrolyte discharge control device according to one embodiment of the present invention.

[0039] Referring to FIGS. 2 to 4, a battery module (10) according to one embodiment of the present invention includes battery cells (110), a module case (300) that accommodates the battery cells (110) inside and has a drain (351), and an electrolyte discharge control device (400).

[0040] As will be described in detail later, the battery module (10) according to the present invention is equipped with an electrolyte discharge control device (400) that normally blocks the drain port, but when the electrolyte level inside the module case rises, opens the drain port for a predetermined period of time to discharge the electrolyte to the outside of the module case, thereby preventing, for example, a bus bar (210) or the like from being immersed in the electrolyte (W) leaking from the battery cells (110). In addition, the electrolyte discharge control device (400) is configured to block the drain port (351) after a predetermined period of time has passed since the electrolyte (W) begins to be discharged to the outside of the battery module (10), thereby preventing the electrolyte (W) outside the battery module (10) from flowing back into the inside of the battery module (10).

[0041] Below, the main configuration of a battery module (10) according to one embodiment of the present invention will be examined.

[0042] As a battery cell (110) according to the present embodiment, a pouch-type battery cell (110) that is easy to stack, as shown in FIG. 3, may be employed. The pouch-type battery cell (110) may include an electrode lead (111), an electrode assembly and an electrolyte (W), and a pouch case that sealingly stores the electrode assembly and the electrolyte (W).

[0043] The above pouch case may be composed of, for example, two pouch sheets. One pouch sheet has a concave groove, and an electrode assembly and an electrolyte (W) are placed in the groove, and the groove is covered with the other pouch sheet, and then the edges of the two pouch sheets are heat-sealed to seal and store the electrode assembly and the electrolyte (W). In such a pouch-type battery cell (110), the portion where the pouch sheets are heat-sealed and sealed is called a sealing portion. The electrode lead (111) has one end connected to the electrode assembly inside the pouch case, and the other end protrudes outside the pouch case, and a portion between the one end and the other end may be heat-sealed and fixed between the two pouch sheets.

[0044] The portion of the electrode lead (111) protruding outside the pouch case can function as an electrode terminal of a pouch-type battery cell (110). Here, the electrode lead (111) includes a positive electrode lead (111) and a negative electrode lead (111). The pouch-type battery cell (110) can be configured such that the positive electrode lead (111) and the negative electrode lead (111) protrude in the same direction from the pouch case or in opposite directions. For reference, the pouch-type battery cell (110) of the present embodiment is a pouch-type battery cell (110) in which the positive electrode lead (111) and the negative electrode lead (111) protrude in opposite directions.

[0045] These pouch-shaped battery cells (110) can be erected in the vertical direction (±Z direction) and stacked in the left-right direction (±Y direction) to form a cell stack (100), as shown in FIG. 3. The battery module (10) can have a high energy density because the cell stack (100) is housed in a module case (300).

[0046] The battery module (10) according to the present embodiment may include a busbar frame assembly (200) as a means for electrically connecting the pouch-type battery cells (110).

[0047] The above busbar frame assembly (200) generally includes a busbar frame (220) which is a plastic injection molded product and busbars (210) which are provided in the form of metal bars such as copper, aluminum, or nickel having electrical conductivity, and can be arranged at the front and / or rear of the cell stack (100).

[0048] The above busbar frame (220) may be provided with slits on the outer surface to which busbars (210) can be fixed and electrode leads (111) can be removed, and may be formed in a roughly plate-shaped shape. The electrode leads (111) of each pouch-type battery cell (110) may pass through the corresponding slits and be drawn outward from the busbar frame (220) and may be brought into contact with and fixed to the corresponding busbars (210) in a predetermined pattern. Laser welding may be performed between the busbars (210) and the electrode leads (111).

[0049] For example, the positive leads of N (N is a natural number) pouch-type battery cells (110) and the negative leads of other N pouch-type battery cells (110) are welded to the same bus bar (210), so that the pouch-type battery cells (110) can be connected in series and / or in parallel.

[0050] Meanwhile, the battery cell (110) constituting the battery module (10) according to the present invention does not necessarily have to be a pouch-type secondary battery. It is to be noted in advance that the pouch-type secondary battery is an example of a battery cell (110) that can be applied to the battery module (10) of the present invention. That is, any type of secondary battery disclosed at the time of filing of the present invention can be the battery cell (110) constituting the battery module (10) according to the present invention. For example, the pouch-type battery cell (110) may be replaced with a cylindrical battery cell (110) or a square battery cell (110) having an external case in the form of a metal can. In this case, the busbar frame assembly (200), unlike the present embodiment, may be modified or replaced with another structure suitable for electrically connecting the cylindrical battery cells (110) or the square battery cells (110).

[0051] The above module case (300) can be made of a material with high mechanical strength so as to protect the battery cells (110) from external impacts, etc.

[0052] Referring to FIGS. 2 and 3, a module case (300) according to one embodiment of the present invention includes a top plate (310) covering an upper portion of a cell stack (100), a bottom plate (320) covering a lower portion of the cell stack (100), a pair of side plates (330, 340) covering both side portions of the cell stack (100), and a pair of end covers (350, 360) covering a busbar frame assembly (200) connecting the front and rear portions of the cell stack (100). An insulating sheet (311) for insulating between the battery cell (110) and the top plate (310) may be optionally attached to the lower surface of the top plate (310).

[0053] The above bottom plate (320) and the pair of side plates (330, 340) may be provided as an integral part. As in the present embodiment, a part in which the bottom plate (320) and the pair of side plates (330, 340) are provided as an integral part is referred to as a U-frame.

[0054] For example, a cell laminate (100) having a busbar frame assembly (200) coupled to the U-frame may be placed, and a top plate (310) (210) may be placed on top of the cell laminate (100). At this time, the top plate (310) and the U-frame may be mutually coupled by welding, bolting, hooking, or the like. When the top plate (310) and the U-frame are coupled, a case body having a roughly square tube shape may be provided.

[0055] The pair of end covers (350, 360) may be configured to cover the front opening and the rear opening of the case body. The busbar frame assembly (200) may be covered by the end covers (350, 360) and may not be exposed to the outside. One end cover (350) of the pair of end covers (350, 360) may have a terminal slit on the upper side. Some of the busbars (210) are exposed to the upper side of the end cover (350) through the terminal slit, and the exposed portions may function as the positive electrode terminal and the negative electrode terminal of the battery module (10). In addition, the end cover (350) may have one or more drain holes (351) formed through the lower side. The drain holes (351) may be used to drain the electrolyte (W) ejected from the battery cells (110) to the outside when a thermal event occurs inside the battery module (10).

[0056] Meanwhile, as illustrated in FIG. 3, the electrolyte discharge control device (400) may cover the drain port (351) and be coupled to the lower end of the end cover (350). The electrolyte discharge control device (400) may be provided to be detachable from the end cover (350) for convenience of maintenance. Although not illustrated in detail, the electrolyte discharge control device (400) may be coupled to the end cover (350) by means of bolting, snap-fit, adhesion, or the like. Unlike the present embodiment, the electrolyte discharge control device (400) may be provided as an integral part with the end cover (350).

[0057] In this embodiment, a drain port (351) and an electrolyte discharge control device (400) are applied to one of the two end covers (350, 360). However, unlike this embodiment, a drain port (351) and an electrolyte discharge control device (400) may be applied to both of the two end covers (350, 360).

[0058] Referring to FIGS. 3 and 4, the electrolyte discharge control device (400) according to the present embodiment will be described in detail. The electrolyte discharge control device (400) includes a storage tank (410), a first blocking film (420), a second blocking film (430), a block support film (440), and a blocking block (450).

[0059] The above storage tank (410) covers the drain (351) and can be provided in the form of a box that is connected to the lower part of the end cover (350) and can accommodate a predetermined amount of electrolyte (W) inside.

[0060] In the present embodiment, all four drain holes (351) in the end cover (350) may be covered by the storage tank (410). The internal space of the storage tank (410) may be divided into four spaces. The four internal spaces may be configured to be separated from each other and communicate independently with the four drain holes (351). In this case, the electrolyte (W) that has flowed into the interior of the storage tank (410) through any one drain hole (351) cannot move in the width direction (Y direction) within the interior of the storage tank (410). That is, the storage tank (410) may be configured so that the electrolyte (W) that has flowed into the storage tank (410) through any one drain hole (351) does not flow back into the remaining drain holes (351) via the internal space of the storage tank (410).

[0061] The first blocking film (420), as illustrated in FIG. 4, may be provided to form one side of the storage tank (410) and to be sized to cover the drain port (351) of the end cover (350). The second blocking film (430) may be provided to be spaced apart from the first blocking film (420) and to form the other side of the storage tank (410). The electrolyte discharge control device (400) of the present embodiment may include four first blocking films (420) and four second blocking films (430). The four first blocking films (420) may cover four drain ports (351) of the end cover (350) one-to-one, respectively, and may be positioned on one side of the storage tank (410). And the four second blocking films (430) may be located on the other side of the storage tank (410) opposite to the four first blocking films (420).

[0062] The first blocking film (420) and the second blocking film (430) may be composed of a material that can be dissolved and lost in the electrolyte (W). For example, the material may be epoxy, water-soluble pulp, bioplastic, etc. Here, the bioplastic may be made of, for example, corn starch, water, fatty acid, oil, etc.

[0063] These first blocking films (420) and second blocking films (430) can melt and disappear after a certain period of time upon contact with the electrolyte (W). Therefore, when the level of the electrolyte (W) inside the module case (300) rises, the first blocking film (420) blocking the drain hole (351) of the end cover (350) can first melt and disappear in the electrolyte (W), allowing the electrolyte (W) to flow into the storage tank (410). Then, when the second blocking film (430) melts and disappears due to the electrolyte (W) flowing into the storage tank (410), the electrolyte (W) can be discharged outside the storage tank (410).

[0064] The first blocking film (420) and the second blocking film (430) include a first region (421, 431) and a second region (423, 433) having different thicknesses, and the thickness (D1) of the first region (421, 431) may be formed to be smaller than the thickness (D2) of the second region (423, 433). In addition, the first region (421, 431) may be provided at a lower position than the second region (423, 433).

[0065] In this case, the electrolyte (W) can smoothly pass through the first blocking film (420) and the second blocking film (430) and be discharged to the outside. That is, the first region (421, 431) having a relatively thin thickness is lost faster by the electrolyte (W) than the second region (423, 433), and since the first region (421, 431) that is lost faster is located lower than the second region (423, 433) that is lost slower, the opening through which the electrolyte (W) can escape expands from the bottom to the top, so that drainage can be performed more smoothly.

[0066] The first blocking film (420) and the second blocking film (430) according to the present embodiment are made of an epoxy material, and the first region can be configured to have a thickness of 100 um to 150 um, and the second region can be configured to have a thickness of 300 um or more.

[0067] The above block support membrane (440) may be placed in a block insertion opening (411a) formed through the upper plate (411) of the storage tank (410). For example, the block insertion opening (411a) may be configured to be blocked at the bottom by the block support membrane (440).

[0068] The above block support film (440) may be made of a material that can be melted and lost by the electrolyte (W), like the first blocking film (420) and the second blocking film (430) described above.

[0069] The above blocking block (450) may be configured to be inserted into the block insertion hole (411a) and supported at the lower end by the block support film (440) and placed on the upper plate (411) of the storage tank (410). In addition, the blocking block (450) may be arranged to close the flow path (S1) between the first blocking film (420) and the second blocking film (430) provided inside the storage tank (410) by falling in the direction of gravity when the block support film (440) is lost due to the electrolyte (W).

[0070] A block slot (413) may be provided in the lower plate (412) of the storage tank (410). The block slot (413) may be formed concavely in the lower plate (412) of the storage tank (410) so that the lower end of the blocking block (450) may be inserted therein.

[0071] The above blocking block (450) may be configured in such a way that when the block support film (440) is lost, it falls due to its own weight, so that the lower end of the blocking block (450) is inserted into the block slot (413) and the upper end of the blocking block (450) cannot come out of the block insertion port (411a). In this case, the blocking block (450) is stably positioned inside the storage tank (410) without being swept in the discharge direction of the electrolyte (W), thereby blocking the flow of the electrolyte (W).

[0072] The above blocking block (450) may be made of a material that has insulating properties and does not dissolve in the electrolyte (W). Preferably, the blocking block (450) may be made of a material with high mechanical strength.

[0073] Meanwhile, the thickness (D3) of the block support film (440) may be set to be thicker than the thickness (D1) of the first region (431) of the second blocking film (430). This is to allow the block support film (440) to dissolve in the electrolyte (W) later than the first region (431) of the second blocking film (430). According to this embodiment, the first region (431) of the second blocking film (430) may be lost first, so that a certain amount of the electrolyte (W) may be discharged outside the storage tank (410), and then the block support film (440) may be lost, so that the blocking block (450) may fall. That is, it is preferable that the block support film (440) be configured to be able to withstand the load of the blocking block (450) under normal conditions and to have a thickness thicker than the first region (431) of the second blocking film (430).

[0074] FIG. 5 is a drawing showing a state in which a drain hole (351) is blocked by an electrolyte discharge control device (400) according to one embodiment of the present invention, FIG. 6 is a drawing showing a state in which a first blocking film (420) is lost in the electrolyte discharge control device (400) of FIG. 5, FIG. 7 is a drawing showing a state in which a second blocking film (430) is lost in the electrolyte discharge control device (400) of FIG. 6, and FIG. 8 is a drawing showing a state in which a support film is lost in the electrolyte discharge control device (400) of FIG. 7 and a blocking block (450) is dropped.

[0075] Next, an operation example of an electrolyte discharge control device (400) of a battery module (10) according to one embodiment of the present invention will be briefly described with reference to FIGS. 5 to 8.

[0076] When a thermal event occurs in the battery cells (110), gas and electrolyte (W) may be ejected from the battery cells (110). If the electrolyte (W) leakage from the battery cells (110) is severe, the level of the electrolyte (W) inside the battery module (10) may increase as shown in FIG. 5. For example, if the level of the electrolyte (W) rises to the height of the bus bars (210), the battery cells (110) may be short-circuited, which may cause secondary fire. However, according to the electrolyte discharge control device (400) according to the present invention, the level of the electrolyte (W) inside the battery module (10) may be lowered, thereby preventing the risk of a short circuit as described above.

[0077] That is, as illustrated in FIGS. 6 and 7, when the level of the electrolyte (W) rises and a predetermined period of time passes, the first blocking film (420) and the second blocking film (430) of the electrolyte discharge control device (400) may sequentially melt into the electrolyte (W) and disappear. As a result, the drain hole (351) of the end cover (350) communicates with the outside, and the electrolyte (W) is discharged to the outside, thereby lowering the level of the electrolyte (W) inside the battery module (10).

[0078] When the battery case collapses due to increased heat and pressure, causing the electrolyte (W) to eject, high-temperature particles (e.g., electrode pieces) are mixed into the electrolyte (W). For this reason, the first blocking film (420) and the second blocking film (430) can be more easily destroyed by the electrolyte (W).

[0079] Meanwhile, after the second blocking film (430) is lost, if the block support film (440) supporting the blocking block (450) is melted and lost by the electrolyte (W), the blocking block (450) may fall in the direction of gravity due to its own weight. As described above, the block support film (440) is provided to be thicker than the first region of the second blocking film (430). In addition, the second blocking film (430) is provided to block the flow of the electrolyte (W) at a position opposite to the flow direction of the electrolyte (W), whereas the block support film (440) is provided on the upper plate (411) of the storage tank (410) parallel to the flow direction of the electrolyte (W). Accordingly, the block support film (440) may be melted and lost by the electrolyte (W) at least more slowly than the first region of the second blocking film (430).

[0080] In this way, when the block support film (440) is lost and the blocking block (450) falls, the flow path (S1) between the first blocking film (420) and the second blocking film (430) may be closed, as shown in Fig. 8. As a result, the drain hole (351) of the end cover (350) may be shielded and not be able to communicate with the outside of the battery module.

[0081] According to the above-described implementation configuration, when a thermal event occurs within the battery module (10), the electrolyte (W) can be discharged so that the level of the electrolyte (W) within the module case (300) does not exceed a certain height. In addition, the electrolyte (W) outside the battery module (10) can be prevented from flowing into the battery module (10) in a certain amount or more. That is, even if the electrolyte (W) outside the battery module (10) sequentially disappears through the second blocking film (430) and the first blocking film (420) and flows into the module case (300) through the drain hole (351) of the end cover (350), when the level of the electrolyte (W) exceeds a certain level, the block support film (440) can be disappeared and the blocking block (450) can fall. Therefore, the electrolyte (W) outside the battery module (10) can be prevented from flowing into the battery module (10) in a certain amount or more.

[0082] FIGS. 9 and 10 are reference drawings for explaining an operation example of an electrolyte discharge control device (400) that further includes a water level detection unit (470) as a battery module according to another embodiment of the present invention.

[0083] The same reference numbers as in the above-described embodiment indicate the same reference numbers, and duplicate descriptions of the same reference numbers will be omitted, and the differences from the above-described embodiment will be mainly explained.

[0084] According to another embodiment of the present invention, an electrolyte discharge control device (400) of a battery module (10) may further include an actuator (460) provided to lift the blocking block (450) upward on the lower plate (412) of the storage tank (410), a level detection unit (470) for detecting the level of the electrolyte (W) inside the module case (300), and a control unit (480) for controlling the actuator (460) to operate based on a signal transmitted from the level detection unit (470).

[0085] The above actuator (460) is a means for lifting the blocking block (450) by a predetermined height so that the flow path (S1) between the first blocking film (420) and the second blocking film (430) is opened again. For example, the actuator (460) may be a rack and pinion actuator (460) including a small motor and a rack and pinion gear, or a solenoid actuator (460). In addition to the actuator (460) described above, any actuator may be used as long as it has a mechanical or electronic mechanism capable of lifting the blocking block (450) upward.

[0086] The above water level detection unit (470) may include a first conductor (471) and a second conductor (473) that are horizontally spaced apart from each other at a predetermined height from the bottom surface of the module case (300), and a current detection unit that detects the current flowing between the first conductor (471) and the second conductor (473) when the electrolyte (W) comes into contact with the first conductor (471) and the second conductor (473).

[0087] In this embodiment, the first conductor (471) and the second conductor (473) may be positioned lower than the bus bars (210) and spaced apart from each other so as not to conduct electricity, and may be installed in the bus bar frame (220). The first conductor (471) and the second conductor (473) may be made of a conductive metal such as copper, aluminum, or the like. In addition, the first conductor (471) and the second conductor (473) may have any shape or structure as long as they conduct electricity when the level of the electrolyte (W) rises and they come into contact with the electrolyte (W) at the same time. Although not shown for convenience of drawing, the first conductor (471) and the second conductor (473) may be connected to one of the battery cells (110) or a separate power source for current detection.

[0088] The current detection unit may include a shunt resistor (475) and a current detection circuit unit (476). For example, the shunt resistor (475) may be installed in a path for electrical connection between the first conductor (471) and the positive terminal of the power source or in a path for electrical connection between the second conductor (473) and the negative terminal of the power source. The current detection circuit unit (476) may be configured to detect current by converting the voltage drop across the shunt resistor (475) into a current value according to Ohm's law, and to transmit a first signal to the control unit (480) when the current value is greater than 0 ampere.

[0089] The control unit (480) is a component that controls the actuator (460) to operate based on the first signal transmitted from the current detection circuit unit (476). The control unit (480) and the actuator (460) may be configured to communicate with each other via wired or wireless communication. The control unit (480) may be integrated into the BMS (Battery Management System) typically included in the battery module (10) so that the BMS performs the role of the control unit (480).

[0090] The battery module (10) further including an actuator (460), a water level detection unit (470), and a control unit (480) as described above can further perform the following functions.

[0091] For example, as illustrated in FIG. 9, in a situation where the flow path (S1) inside the storage tank (410) is closed by the blocking block (450), the electrolyte (W) may be additionally ejected from the battery cells (110), causing the level of the electrolyte (W) inside the battery module (10) to rise again.

[0092] When the level of the electrolyte (W) rises to the height of the first conductor (471) and the second conductor (473), as illustrated in FIG. 10, the first conductor (471) and the second conductor (473) become electrically connected. Then, the current detection circuit (476) detects the electrical current and transmits the first signal to the control unit (480). The control unit (480) transmits an operation signal to the actuator (460) based on the first signal, and at this time, the actuator (460) operates to push up the blocking block (450). As a result, the flow path (S1) in the storage tank (410) is opened again, so that the electrolyte (W) can be discharged to the outside of the battery module (10).

[0093] Meanwhile, when a certain amount of electrolyte (W) is discharged to the outside of the battery module (10) and the level of the electrolyte (W) drops below the first conductor (471) and the second conductor (473), no current flows between the first conductor (471) and the second conductor (473). In this case, the current detection circuit unit (476) may be configured to transmit a second signal to the control unit (480), and the control unit (480) may be configured to transmit a signal to the actuator (460) to control the operation of the actuator (460) so that the blocking block (450) is lowered again after a predetermined period of time has elapsed after receiving the second signal.

[0094] According to the implementation configuration according to the present invention, even after the first blocking film (420) and the second blocking film (430) are lost, the level of the electrolyte (W) inside the battery module (10) can be controlled to be below a certain height.

[0095] The battery pack according to the present invention may include one or more of the above-described battery modules (10). The battery pack according to the present invention may further include a master BMS (Battery Management System) for integrated control of charging and discharging of one or more battery modules (10) and a pack case for accommodating the above-described battery modules (10).

[0096] The battery pack according to the present invention can be used, for example, as a driving energy source for an electric vehicle. That is, the battery pack can be used as an electric energy source to drive a motor and drive the vehicle. The battery pack can be charged or discharged by an inverter depending on the operation of the motor and / or internal combustion engine. The battery pack can be charged by a regenerative charging device combined with a brake. The battery pack can be electrically connected to the vehicle's motor via an inverter.

[0097] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0098] In addition, although terms indicating directions such as up, down, left, and right are used in this specification, it is obvious to those skilled in the art that these terms are only for convenience of explanation and may vary depending on the location of the target object or the location of the observer.

Claims

1. Battery cells; A module case that houses the battery cells therein and has a drain for draining electrolyte leaking from the battery cells; and A battery module characterized in that it includes an electrolyte discharge control device configured to block the drain port, and when the electrolyte level inside the module case rises, open the drain port for a predetermined period of time and then block the drain port.

2. In paragraph 1, The above electrolyte discharge control device is, A storage tank coupled to the above module case; A first barrier covering the drain and forming one side of the storage tank; A second barrier film spaced apart from the first barrier film and forming the other side of the storage tank; A block support membrane placed in a block insertion hole formed through the upper part of the storage tank; and A blocking block is provided which is supported at the bottom by the block support membrane and is disposed on the upper part of the storage tank, and is provided to close the passage between the first blocking membrane and the second blocking membrane provided inside the storage tank by falling in the direction of gravity when the block support membrane is lost due to the electrolyte. A battery module characterized in that the first blocking film, the second blocking film, and the block support film are composed of a material that can be dissolved and lost in an electrolyte.

3. In paragraph 2, The above first and second barriers, A battery module comprising a first region and a second region having different thicknesses, wherein the first region is formed to have a thickness smaller than that of the second region and is provided at a lower position than the second region.

4. In paragraph 3, A battery module characterized in that the first region has a thickness of 100 um to 150 um, and the second region has a thickness of 300 um or more.

5. In paragraph 3, A battery module, characterized in that the block support film has a thickness greater than the thickness of the first region.

6. In paragraph 2, A battery module characterized in that the above blocking block is made of an insulating material.

7. In paragraph 2, A battery module characterized in that the first blocking film, the second blocking film, and the block support film are made of at least one material selected from the group consisting of epoxy, water-soluble pulp, and bioplastic.

8. In paragraph 2, The above electrolyte discharge control device is, A battery module characterized in that it includes a block slot concavely formed in the lower part of the storage tank so that the lower part of the blocking block can be inserted.

9. In paragraph 2, The above electrolyte discharge control device is, An actuator provided to lift the blocking block upward on the lower part of the storage tank; A water level detection unit that detects the level of the electrolyte inside the above module case; and A battery module characterized by including a control unit that controls the actuator to operate based on a signal transmitted from the water level detection unit.

10. In paragraph 9, The above water level detection unit, First conductors and second conductors spaced apart horizontally at a predetermined height from the bottom surface of the module case; and A battery module characterized by including a current detection unit that detects a current flow between the first conductor and the second conductor when an electrolyte comes into contact with the first conductor and the second conductor.

11. In paragraph 1, A busbar frame assembly having a plurality of busbars electrically connecting the battery cells and a busbar frame supporting the plurality of busbars; and Further comprising an end cover covering the above busbar frame assembly, A battery module characterized in that the drain hole is provided at the lower part of the end cover.

12. In paragraph 11, The above electrolyte discharge control device is, A battery module characterized in that it is detachably connected to the lower part of the end cover.

13. A battery pack comprising a battery module according to any one of claims 1 to 12.

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