Battery module and battery pack including same

Abstract

A battery module according to the present invention comprises: a cell stack composed of stacked battery cells; a module case which accommodates the cell stack, and which has gas venting holes provided in a bottom plate positioned at the bottom of the cell stack; and venting induction unit having a needle member that protrudes from the gas venting hole so as to form a hole in the battery cell, and a needle stopper member that can prevent the needle member from protruding while no deformation occurs due to heat or external force.

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 excellent safety against thermal events and a battery pack including the same.

[0002] This application claims priority to Korean Patent Application No. 10-2023-0125887, filed on September 20, 2023, and all contents disclosed in the specification and drawings of that application are incorporated herein by reference.

[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] Therefore, battery modules or battery packs need measures to prevent fire or reduce its spread in case of a thermal event.

[0008] For example, if a thermal event occurs in a battery module, gas or flames may be generated, causing heat to accumulate internally. This can rapidly propagate between battery cells. This can result in multiple battery cells igniting simultaneously, making it difficult to extinguish the thermal event. Furthermore, the damage can be exacerbated by an explosion of the battery module.

[0009] Accordingly, when a thermal event occurs in a battery module, a method is required to effectively discharge thermal energy within the battery module so that thermal runaway propagation and ignition between battery cells can be delayed as much as possible.

[0010] The present invention was created to solve the above technical problems, and its primary purpose is to provide a battery module that can effectively relieve heat and pressure inside the battery module when a thermal event occurs in the battery module.

[0011] 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.

[0012] A battery module according to one aspect of the present invention comprises: a cell stack formed of stacked battery cells; a module case accommodating the cell stack and having a gas venting hole in a bottom plate; and a venting induction unit having a needle member configured to protrude from the gas venting hole and make a hole in the battery cell, and a needle stopper member configured to prevent the needle member from protruding while not being deformed by heat or external force.

[0013] The above needle stopper member can be made of a material that can be heat melted at a predetermined temperature.

[0014] The above needle stopper member may have a notch line so as to be broken by a predetermined pressure.

[0015] The above needle member may include an elastic member vertically arranged in the gas venting hole; a needle portion coupled to an upper end of the elastic member; and an elastic fixing portion coupled to a lower end of the elastic member and fixed to a bottom plate of the module case.

[0016] The above needle stopper member may include a blocking portion that blocks the needle portion at the upper portion of the gas venting hole; and a stopper fixing portion that is connected to the blocking portion and fixed to the bottom plate of the module case.

[0017] A notch line may be provided at the boundary between the above blocking portion and the above stopper fixing portion.

[0018] At least one of the above blocking portion and the above stopper fixing portion may be composed of a heat-meltable resin material.

[0019] The above needle portion may include a needle plate coupled to the upper end of the elastic member and positioned below the blocking portion; and one or more needles protruding from the needle plate.

[0020] The one or more needles may be configured to be embedded within the blocking portion.

[0021] The above battery cells are pouch-type battery cells, and the gas venting holes are provided at predetermined intervals along the width direction of the bottom plate, and the gas venting holes can be provided at positions corresponding vertically to cell terraces formed by heat-sealing a pouch sheet in the pouch-type battery cells.

[0022] The above venting induction unit is provided in each of the gas venting holes, and the gas venting hole and the venting induction unit can be provided on the front and rear sides of the bottom plate of the module case.

[0023] The module case may include a top plate covering the upper portion of the cell stack; a bottom plate covering the lower portion of the cell stack; a pair of side plates covering each of the two side portions of the cell stack; and a pair of end covers covering the front and rear portions of the cell stack, respectively.

[0024] The battery further comprises: a busbar electrically connected to electrode leads provided in the battery cells; and a busbar frame that supports the busbars and has a lead slot through which the electrode leads can pass, and is mounted on a front or rear portion of the cell stack; wherein the busbars include a first busbar and a second busbar that are overlapped with the electrode leads interposed therebetween, and the electrode leads can be press-fixed between the first busbar and the second busbar.

[0025] The battery cells are pouch-type battery cells, each having a wide surface that is upright and stacked in one direction, and the cell stack includes a plurality of barrier plates that are inserted between the battery cells at predetermined intervals along the one direction to limit the movement of heat or gas between the battery cells, and each of the plurality of barrier plates may be configured such that an end portion thereof is fitted into the busbar frame so that the battery cells and the gas venting holes are divided into a predetermined number of units.

[0026] According to another aspect of the present invention, a battery pack including the above-described battery module can be provided.

[0027] According to one aspect of the present invention, an object of the present invention is to provide a battery module capable of effectively dissipating heat and pressure inside the battery module when a thermal event occurs in the battery module.

[0028] In particular, the venting induction unit according to the present invention can form a hole in a trigger battery cell exhibiting thermal abnormalities, thereby allowing high-temperature gases, particles, etc. from the trigger battery cell to be discharged early to the outside of the module case under low pressure. This can reduce thermal damage to adjacent battery cells.

[0029] 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.

[0030] FIG. 1 is a schematic perspective view of a battery module according to one embodiment of the present invention.

[0031] Figure 2 is an exploded perspective view of the battery module of Figure 1.

[0032] Figure 3 is a perspective view illustrating the cell stack of Figure 2.

[0033] FIG. 4 is a perspective view illustrating a portion of a module case according to one embodiment of the present invention.

[0034] Figure 5 is a partially enlarged view of Figure 4.

[0035] Figure 6 is a perspective view illustrating the configuration of a venting induction unit according to one embodiment of the present invention.

[0036] FIG. 7 is a drawing showing an application example of a venting induction unit applied to a gas venting hole in a battery module according to one embodiment of the present invention.

[0037] Figure 8 is a schematic cross-sectional view of a battery module according to one embodiment of the present invention.

[0038] Figure 9 is an enlarged view of area A of Figure 8.

[0039] Fig. 10 is a drawing corresponding to Fig. 9, showing an example in which the needle stopper member is broken and the needle portion protrudes from the gas venting hole.

[0040] FIG. 11 is a drawing for explaining an assembly example of a cell laminate and a busbar frame according to one embodiment of the present invention.

[0041] Fig. 12 is a drawing showing a busbar frame in which a frame cover and a compression busbar are combined in Fig. 11.

[0042] FIG. 13 is a schematic cross-sectional view of a mutually assembled cell stack and busbar frame according to one embodiment of the present invention.

[0043] FIG. 14 is a schematic drawing of a vehicle including a battery pack according to one embodiment of the present invention.

[0044] 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 modifications may exist as of the time of this application.

[0045] 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.

[0046] FIG. 1 is a schematic perspective view of a battery module according to one embodiment of the present invention, FIG. 2 is an exploded perspective view of the battery module of FIG. 1, FIG. 3 is a perspective view illustrating a cell stack of FIG. 2, and FIG. 4 is a perspective view illustrating a portion of a module case according to one embodiment of the present invention.

[0047] Referring to FIGS. 1 to 4, a battery module (10) according to one embodiment of the present invention includes a cell stack (100) composed of stacked battery cells (110), a module case (200) that accommodates the cell stack (100) and has a gas venting hole (201) in a bottom plate (220), and a venting induction unit (300) disposed in the gas venting hole (201).

[0048] The above cell stack (100) is formed by stacking a plurality of battery cells (110) in a horizontal direction, as shown in FIGS. 2 and 3. The battery cell (110) according to the present embodiment is a pouch-type battery cell (110). Each of the pouch-type battery cells (110) has a wide surface that is upright and can be stacked in one direction. The pouch-type battery cell (110) includes an electrode lead (111), an electrode assembly and an electrolyte, and a pouch case that sealingly stores the electrode assembly and the electrolyte.

[0049] The above pouch case may be composed of two pouch sheets, at least one of which may have a concave groove formed therein. An electrode assembly and an electrolyte are placed in the groove, and the edges of the two pouch sheets are heat-sealed. In such a pouch-type battery cell (110), a 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, the other end protruding outside the pouch case, and a portion between the one end and the other end is fixed within the sealing portion when the pouch sheet is heat-sealed. A portion of the electrode lead (111) exposed to the outside of the pouch case may function as an electrode terminal of the pouch-type battery cell (110).

[0050] For reference, a pouch-type battery cell (110) that packages an electrode assembly with two pouch sheets has four sealing portions. Here, the four sealing portions refer to a front sealing portion, a rear sealing portion, from which the electrode lead (111) protrudes, and two side sealing portions extending in the longitudinal direction of the electrode assembly. On the other hand, a pouch-type battery cell (110) that packages an electrode assembly by folding one pouch sheet has three sealing portions. Here, the three sealing portions refer to a front sealing portion, a rear sealing portion, from which the electrode lead (111) protrudes, and one side sealing portion. In particular, in the pouch-type battery cell (110), the front sealing portion and the rear sealing portion are referred to as cell terraces (112).

[0051] Meanwhile, the cell stack (100) according to the present embodiment further includes battery cells (110) and barrier plates (120) for partitioning the battery cells (110). The barrier plates (120) will be described later for convenience of explanation.

[0052] The above module case (200) may be composed of a case body and a pair of end covers (250, 260) as shown in FIGS. 1 and 2.

[0053] The case body may include a top plate (210) covering the upper portion of the cell stack (100), a bottom plate (220) covering the lower portion of the cell stack (100), and a pair of side plates (230, 240) covering both side portions of the cell stack (100), respectively.

[0054] The bottom plate (220) and the pair of side plates (230, 240) may be formed integrally. The bottom plate (220) and the pair of side plates (230, 240) provided integrally are also referred to as a U-frame. The U-frame and the top plate (210) may be joined by a method such as bolting, welding, or adhesion. Meanwhile, unlike the present embodiment, the top plate (210), the bottom plate (220), and the pair of side plates (230, 240) may be formed integrally in a square tube shape. The end cover (250, 260) may be opened from the case body and joined to the front and rear.

[0055] In the present embodiment, referring to FIGS. 1 and 2, the top plate (210) may be provided with a terminal through hole through which the terminal bus bar of the battery module (10) can be extended upward. The terminal bus bar includes a positive terminal bus bar (410a) and a negative terminal bus bar (410b). However, unlike the present embodiment, the terminal bus bar may be designed to face forward, for example, by penetrating the end cover (250).

[0056] A thermal resin (TR) may be applied to the bottom plate (220). The thermal resin (TR) promotes heat exchange between the battery cells (110) and the bottom plate (220) and increases the fixation of the battery cells (110) to the bottom plate (220). The battery cells (110) are provided in a form in which their wide surfaces are upright and stacked in the width direction of the bottom plate (220). In this case, the lower edge surfaces of all the battery cells (110) can come into contact with the thermal resin (TR). Therefore, since heat from each battery cell (110) is transferred to the bottom plate (220) through the thermal resin (TR), the heat of the battery cells (110) can be efficiently dissipated to the outside during charging and discharging.

[0057] Referring again to FIG. 2 or FIG. 4, the bottom plate (220) is provided with a gas venting hole (201). The gas venting hole (201) prevents a pressure difference between the inside and outside of the module case (200) under normal conditions, and prevents excessive heat accumulation inside the battery module (10) by discharging high-temperature gases, etc. emitted from the battery cell (110) when a thermal event occurs. In addition, since the gas can be discharged to the outside through the gas venting hole (201), collapse or explosion of the battery module (10) due to a rapid increase in internal pressure can be prevented.

[0058] The above gas venting hole (201) may be provided in the lower area of ​​the cell terrace (112) of the battery cell (110).

[0059] Specifically, the gas venting holes (201) according to the present embodiment may be provided at predetermined intervals along the width direction of the bottom plate (220), as illustrated in FIG. 2. When the cell stack (100) is housed in the module case (200), they may be provided at positions corresponding vertically to the cell terraces (112) of the pouch-type battery cells (110). The pouch-type battery cell (110) of the present embodiment has two cell terraces (112) at the front and rear. Corresponding to the structure of the pouch-type battery cell (110), the gas venting holes (201) according to the present embodiment may be respectively configured at the front and rear sides of the bottom plate (220) of the module case (200).

[0060] That is, a plurality of gas venting holes (201) may be provided in the bottom plate (220) to correspond to the number and positions of the cell terraces (112) of the pouch-type battery cells (110). The number of the gas venting holes (201) is plural, and they may be provided at regular intervals along the width direction (X direction) at positions close to both ends along the length direction (Y direction) of the bottom plate (220).

[0061] And, as shown in Fig. 2, the thermal resin described above can be configured to be distributed on the bottom plate (220) only to a position adjacent to the gas venting holes (201) so that the gas venting holes (201) are not blocked.

[0062] Preferably, the gas venting holes (201) can be configured at positions corresponding vertically to the cell terraces (112) in the pouch-type battery cell (110).

[0063] Secondary batteries may generate gas as a side reaction during charging and discharging. In particular, if a large amount of gas is generated during overcharge and discharge, which causes a significant increase in internal pressure, swelling may occur, and if this worsens, the bonding strength of the heat-sealed sealing portion may weaken, causing the portion to tear and releasing gas. At this time, among the sealing portions of the pouch-type battery cell (110), the cell terrace (112) generates relatively more heat and has a lower bonding strength than other portions due to the electrode lead (111) intervening therein. As a result, the pouch-type battery cell (110) is most likely to be damaged in the cell terrace (112) portion when the internal pressure increases.

[0064] Accordingly, in accordance with one embodiment of the present invention, the battery module (10) has gas venting holes (201) configured in the edge areas on both sides of the bottom plate (220) corresponding vertically to the cell terrace (112) so that gases emitted when the cell terrace (112) is damaged can be immediately discharged to the outside of the battery module (10).

[0065] According to the above configuration, when a high-temperature gas, etc. is emitted from a trigger battery cell (110) among the battery cells (110) where a thermal event has occurred, it is easy to discharge the high-temperature gas, etc. toward the lower side of the module case (200) through the gas venting hole (201). In this case, other battery cells (110) adjacent to the trigger battery cell (110) may not suffer significant thermal damage. In addition, since a large amount of gas can be quickly discharged to the outside of the battery module (10), a phenomenon in which the internal pressure of the battery module (10) rapidly increases can be prevented.

[0066] Meanwhile, a battery module (10) according to one embodiment of the present invention may include a venting induction unit (300) having a needle member (310) configured to pop up from the gas venting hole (201) and make a hole in the battery cell (110), and a needle stopper member (320) configured to prevent the needle member (310) from popping up while deformation does not occur due to heat or external force.

[0067] The above venting induction unit (300) may be provided for each gas venting hole (201), as shown in FIGS. 2 and 4. In addition, the gas venting hole (201) and the venting induction unit (300) may be provided on the front and rear sides of the bottom plate (220) of the module case (200).

[0068] As described in detail below, the battery module (10) according to the present invention has the venting induction unit (300) installed in the gas venting hole (201), so that when a thermal event occurs, a hole is made in the cell terrace (112) of the battery cell (110), and heat energy can be quickly released from the inside of the battery cell (110) through the hole.

[0069] Referring mainly to FIGS. 4 to 7, the main components of the venting induction unit (300) are examined. The venting induction unit (300) includes a needle member (310) and a needle stopper member (320).

[0070] First, the needle member (310) is a component that causes a crack or creates a hole in the pouch case of the battery cell (110) that overheats during charging and discharging, thereby inducing the discharge of gas, etc., inside the battery cell (110). In particular, the battery module (10) of the present invention is configured so that, when a thermal event occurs, the needle member (310) damages a specific portion of the battery cell (110), thereby allowing high-temperature gas, etc., inside the battery cell (110) to be discharged in a specific direction.

[0071] For example, the battery module (10) of the present invention may be configured so that the needle member (310) can pop up from the gas venting hole (201) when a thermal event occurs, so that the cell terrace (112) area of ​​the battery cell (110) can be punctured or damaged. According to the configuration, for example, when the needle member (310) pops up from the lower portion of the cell terrace (112) while gas is trapped in the cell terrace (112), a hole is formed in the cell terrace (112), and at this time, gas can escape from the inside of the battery cell (110) and be directionally vented in the lower direction of the bottom plate (220) through the gas venting hole (201). Meanwhile, even if the needle member (310) pops up while the cell terrace (112) is not expanded, if the cell terrace (112) area expands later, the cell terrace (112) may be torn or cracked by the needle member (310), so that gas discharge to the outside may be concentrated in the cell terrace (112) area.

[0072] Specifically, the needle member (310) may include an elastic member (311) vertically arranged in the gas venting hole (201), a needle portion (312) coupled to the upper end of the elastic member (311), and an elastic fixing portion (313) coupled to the lower end of the elastic member (311) and fixed to the bottom plate (220) of the module case (200).

[0073] In this embodiment, a compression spring is employed as the elastic member (311). However, as an alternative to the compression spring, any structure capable of being compressed and stretched, such as elastic rubber or bellows, may be employed as the elastic member (311).

[0074] The above needle portion (312) may include a needle plate (312a) coupled to the upper end of the elastic member (311) and one or more needles (312b) protruding from the needle plate (312a).

[0075] The needle plate (312a) is preferably made of a material with excellent heat resistance and may be provided in a plate-like shape. The needle plate (312a) and the compression spring may be joined, for example, by welding or adhesive bonding.

[0076] The needle (312b) has a tip. For example, the needle (312b) may be shaped like a cone, rod, pin, or the like, as long as it has a tip capable of forming a hole in the pouch case. The needle (312b) may be formed integrally with the needle plate (312a) or may be provided with a structure that can be detachably attached to the needle plate (312a).

[0077] The above needle (312b) may be one or more. For example, when a plurality of needles (312b) are formed as in the present embodiment, multiple holes may be formed in the cell terrace (112). In addition, in the case of a cell stack (100) composed of multiple battery cells (110) stacked in a horizontal direction as in the present embodiment, the cell terraces (112) of adjacent battery cells (110) may expand simultaneously due to heat propagation. At this time, if the cell terraces (112) of the adjacent battery cells (110) are located in the upper region of the multiple needles (312b), holes may be formed in all of the cell terraces (112).

[0078] The above elastic fixing member (313) is preferably made of a material with excellent heat resistance and may be provided in a plate-like shape. The above elastic fixing member (313) and the compression spring may be joined, for example, by welding or adhesive bonding.

[0079] The elastic fixing part (313) according to the present embodiment may be attached to the lower surface of the bottom plate (220). For example, the elastic fixing part (313) may be positioned at the lower portion of the gas venting hole (201), as shown in FIG. 7, and both ends may be welded or adhesively joined to the bottom plate (220) of the module case (200). At this time, the compression spring may be configured to be vertically arranged inside the gas venting hole (201) at the center of the elastic fixing part (313). Meanwhile, unlike the present embodiment, the elastic fixing part (313) may be formed integrally with the bottom plate (220) of the module case (200).

[0080] The compression spring can be positioned within the gas venting hole (201) by the elastic fixing member (313) and can be compressed by the needle stopper member (320).

[0081] Referring to FIGS. 5 and 6, the needle stopper member (320) may include a blocking portion (321) that blocks the needle portion (312) at the upper portion of the gas venting hole (201) and a stopper fixing portion (323) that is connected to the blocking portion (321) and fixed to the bottom plate (220) of the module case (200).

[0082] The above stopper fixing part (323) can be fixedly connected at least at one end to the upper surface of the bottom plate (220) of the module case (200). For example, in the present embodiment, the stopper fixing part (323) can be provided in a form that extends from one side and the other side of the blocking part (321) and can be attached to the upper surface of the module case (200). Various methods, such as welding, adhesion, and hook fastening, can be employed to fix the stopper fixing part (323) to the bottom plate (220) of the module case (200).

[0083] The above blocking portion (321) may be arranged vertically above the needle plate (312a). For example, the blocking portion (321) may be arranged to face the needle plate (312a) so as to prevent the needle plate (312a) from springing up by the compression spring. At this time, one or more needles (312b) may be configured to be embedded in the inside of the blocking portion (321). Although not illustrated in detail in the drawing, the blocking portion (321) may have a hole into which the needle (312b) may be inserted.

[0084] In addition, the blocking portion (321) is formed integrally with the stopper fixing portion (323) fixed to the upper surface of the bottom plate (220) of the module case (200). Therefore, even if the blocking portion (321) receives an external force by a compression spring, a reaction force is generated in the blocking portion (321) so that the needle plate (312a) does not bounce up.

[0085] The needle stopper member (320) comprising the blocking portion (321) and the stopper fixing portion (323) as described above may be prepared from a material that can be heat melted at a predetermined temperature. In addition, the needle stopper member (320) may be provided with a notch line (322) so as to be broken by a predetermined pressure.

[0086] According to the above configuration, the needle portion (312) cannot normally pop out of the gas venting hole (201) because it is blocked by the needle stopper member (320). However, if the needle stopper member (320) is damaged or thermally melted by external pressure and falls off from the bottom plate (220) of the module case (200) or a portion thereof melts and disappears, the needle portion (312) may pop out of the gas venting hole (201). At this time, the needle portion (312) may form a crack or hole in the pouch case of the battery cell (110). Then, gas or heat energy inside the battery cell (110) can be quickly discharged to the outside through the gas venting hole (201). That is, since the high-temperature gas or high-temperature particles generated in the battery cell (110) where the event occurred are discharged from the module case (200) to the outside through the gas venting hole (201) via the shortest path, heat accumulation inside the module case (200) and thermal runaway propagation between the battery cells (110) can be minimized.

[0087] At least one of the blocking portion (321) and the stopper fixing portion (323) constituting the needle stopper member (320) may be made of a heat-meltable resin material, and the others may be made of a metal material with excellent heat resistance. For example, the blocking portion (321) may be made of a Styrofoam, rubber, or plastic material, and the stopper fixing portion (323) may be made of a metal material such as aluminum, copper, or steel.

[0088] When the needle stopper member (320) is configured in this manner, heat generated from the battery cell (110) can be absorbed into the stopper fixing portion (323) through the thermal pad and / or the bottom plate (220) of the module case (200), and the heat absorbed by the stopper fixing portion (323) can be transmitted to the blocking portion (321). As a result, the blocking portion (321) melts and falls off from the stopper fixing portion (323), and at this time, the needle portion (312) can pop out of the gas venting hole (201) by the elastic force of the compression spring.

[0089] The needle stopper member (320) may be provided so that the boundary between the blocking portion (321) and the stopper fixing portion (323) can be broken when an external force of a certain strength or greater is applied together with heat. To this end, the needle stopper member (320) according to the present embodiment has a notch line (322) at the boundary between the blocking portion (321) and the stopper fixing portion (323). The notch line (322) may be provided in the form of a groove that is sunken to a predetermined depth from the surface of the needle stopper member (320) and continues intermittently or continuously in the width direction. The needle stopper member (320) may be broken at the notch line (322) portion due to an increase in the internal pressure of the module case (200) or the wind pressure of the gas escaping through the gas venting hole (201), thereby separating the blocking portion (321) and the stopper fixing portion (323). That is, the above needle stopper member (320) may be detached from the stopper fixing member (323) by pressure rather than heat.

[0090] FIG. 8 is a schematic cross-sectional view of a battery module (10) according to one embodiment of the present invention, FIG. 9 is an enlarged view of area A of FIG. 8, and FIG. 10 is a drawing corresponding to FIG. 9, which illustrates an example in which a needle stopper member (320) is broken and a needle portion (312) protrudes from a gas venting hole (201).

[0091] Hereinafter, an operation example of a venting induction unit (300) according to one embodiment of the present invention will be briefly described with reference to FIGS. 8 to 10.

[0092] As shown in FIG. 8, a battery module (10) according to one embodiment of the present invention has gas venting holes (201) provided on the front and rear sides of a bottom plate (220) of a module case (200). Here, the front and rear sides of the bottom plate (220) of the module case (200) mean positions corresponding to the lower portion of a front cell terrace (112) of a battery cell (110) and the lower portion of a rear cell terrace (112) of a battery cell (110).

[0093] And the battery module (10) includes a venting induction unit (300) installed in the gas venting hole (201), as shown in FIG. 9. As described above, while the needle stopper member (320) is not deformed by heat or external force, the needle member (310) is blocked by the needle stopper member (320) and does not protrude from the gas venting hole (201). That is, while there is no thermal event inside the battery module (10), the needle portion (312) does not protrude from the gas venting hole (201) and cause damage to the battery cell (110).

[0094] However, if the temperature of the battery cell (110) rises rapidly due to, for example, a short circuit issue of the battery cell (110), thermal deformation may occur in the needle stopper member (320). At this time, the path by which heat is transferred from the battery cell (110) to the needle stopper member (320) may vary. For example, as indicated by 'H1' in FIG. 9, heat may be transferred from the battery cell (110) to the stopper fixing member (323) through the thermal resin (TR) or the bottom plate (220) of the module case (200). In addition, if gas is generated inside the battery cell (110) and the cell terrace (112) expands, and at this time, if the blocking part (321) of the needle stopper member (320) is exposed to heat and pressure from the expanded cell terrace (112), as indicated by 'H2', the blocking part (321) may melt or the notch line (322) may break.

[0095] In this way, when deformation occurs in the needle stopper member (320) due to heat or external force, as shown in FIG. 10, the elastic force of the compression spring (311) becomes greater than the reaction force of the blocking portion (321), so that the compression spring (311) pushes the needle portion (312) up onto the gas venting hole (201). Then, a hole or crack may be created in the cell terrace (112) by the needle (312b) protruding above the gas venting hole (201). As a result, high-temperature gas, particles, etc. in the battery cell (110) can be effectively directional vented to the outside through the gas venting hole (201) of the module case (200) at an early stage. Therefore, according to the venting induction unit (300) of the present invention, it is possible to prevent heat and pressure from accumulating inside the battery module (10), thereby delaying thermal runaway of the battery module (10) locally.

[0096] FIG. 11 is a drawing for explaining an assembly example of a cell laminate (100) and a busbar frame (400) according to one embodiment of the present invention, FIG. 12 is a drawing showing a busbar frame (400) in which a frame cover (500) and a compression busbar are combined in FIG. 11, and FIG. 13 is a schematic cross-sectional view of a mutually assembled cell laminate (100) and a busbar frame (400) according to one embodiment of the present invention.

[0097] Referring to FIG. 2 and FIG. 11 to FIG. 13, a battery module (10) according to one embodiment of the present invention may further include a plurality of bus bars (410, 600) electrically connected to electrode leads (111) provided in battery cells (110), a bus bar frame (400), a frame cover (500), and a sealing cover (700).

[0098] The above bus bars (410, 600) may be formed of a metal such as copper or aluminum having electrical conductivity and provided in the form of a bar.

[0099] The above busbar frame (400) can be provided in a plate shape that can support the busbars (410, 600) and cover the front and rear portions of the cell stack (100), respectively. Here, the busbar frame (400) can be formed of an electrically insulating material such as plastic. In addition, the busbar frame (400) can be provided with lead slots (420) through which electrode leads (111) can pass. The electrode leads (111) of the battery cells (110) can pass through the lead slots (420) and be attached to the busbars in a predetermined pattern.

[0100] In particular, the battery module (10) of the present embodiment is configured to secure the electrode leads (111) to the bus bars by compressing them rather than welding them to the bus bars. Accordingly, the assembly time of the battery module (10) can be shortened and the assembly process can be carried out more easily.

[0101] Specifically, a bus bar according to an embodiment of the present invention includes a first bus bar (410) and a second bus bar (600). Referring to FIGS. 11 and 12, the first bus bar (410) and the second bus bar (600) may be overlapped with the electrode lead (111) therebetween. In addition, the electrode lead (111) may be press-fixed between the first bus bar (410) and the second bus bar (600). At this time, by fastening the first bus bar (410) and the second bus bar (600) using a fastening member (800) such as a bolt, the state in which the electrode lead (111) is pressed between the first bus bar (410) and the second bus bar (600) can be stably maintained.

[0102] The above frame cover (500) is provided in the form of a pad made of a material having low thermal conductivity and excellent heat resistance, such as silicone, aerogel, or mica, and can be coupled to the busbar frame (400) so as to face it, as shown in FIG. 12. The frame cover (500) may include a plurality of cover plates (510). Each cover plate (510) may be provided to correspond to the partition surfaces of the busbar frame (400) partitioned by the partition walls (430) protruding from the busbar frame (400) and the end portions (121) of the barrier plate (120) to be described later. Here, the partition walls (430) and the end portions (121) of the barrier plate (120) may serve to prevent short circuits between the electrode leads (111).

[0103] When the above frame cover (500) is attached to the busbar frame (400), the lead slots (420) of the busbar frame (400) can be covered. With this configuration, when a thermal event occurs, high-temperature gas or flames may not leak out to the front or rear of the cell stack (100) through the lead slots (420).

[0104] The electrode leads (111) are bent in a predetermined pattern and placed on the front surface of the corresponding first bus bars (410), and then the frame cover (500) can be attached to the bus bar frame (400). Here, the frame cover (500) has a bus bar insertion hole (H). The second bus bar (600) can be configured to be coupled to the first bus bar (410) with the electrode leads (111) interposed therebetween through the bus bar insertion hole (H).

[0105] The above-mentioned sealing cover (700) is a component for sealing the frame cover (500) to the busbar frame (400) and also sealing the second busbar (600) toward the electrode lead (111) and the first busbar (410).

[0106] The above-described sealing cover (700) may be composed of a plurality of sealing plates (710), as illustrated in FIG. 12. The sealing plates (710) may be provided in a number corresponding to the number of bus bars, and each sealing plate (710) may be fixedly coupled to each corresponding bus bar by a fastening member (800). In addition, the sealing plates (710) may be attached between the end portions (121) of the barrier plates (120) penetrating the bus bar frame (400) and the partition walls (430) protruding from the bus bar frame (400). The sealing plates (710) may be made of a material having high mechanical rigidity and flame retardant properties. For example, the sealing plates (710) may be made of a rigid material having a high melting point, such as SUS, which is insulated, or a rigid material having fire resistance and insulation properties.

[0107] As described above, the cell stack (100) according to one embodiment of the present invention may include a plurality of barrier plates (120) that are interposed between battery cells (110) at predetermined intervals along one direction to limit the movement of heat or gas between the battery cells (110).

[0108] Each of the plurality of barrier plates (120) can be fitted with the terminal portion (121) of the bus bar frame (400) so that the battery cells (110) and the gas venting holes (201) are divided into a predetermined number of units, as shown in FIGS. 12 and 13.

[0109] The above barrier plate (120) may be provided in the form of a compressible pad and made of a material with excellent heat resistance and / or fire resistance, such as silicone, aerogel, mica, etc.

[0110] As illustrated in FIG. 13, the barrier plate (120) can perform a thermal barrier function that blocks heat, such as a flame, generated from an ignited battery cell (110) from spreading in the stacking direction of the battery cells (110). Therefore, heat propagation to neighboring battery cells (110) can be minimized. The barrier plate (120) can block not only heat but also high-temperature gases, flames, discharged substances, etc. generated from the battery cells (110). Accordingly, the barrier member can partition or separate the battery cells (110) to prevent flames, etc. from spreading between the battery cells (110).

[0111] Meanwhile, a battery pack (not shown) 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), a current sensor, a fuse, and a pack case for accommodating the above-described components.

[0112] Referring to FIG. 14, the battery pack according to the present invention can be used 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 according to 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 motor of the vehicle through an inverter.

[0113] 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 can be made 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 skilled in the art to which the present invention pertains.

[0114] 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. A cell stack composed of stacked battery cells; A module case having a bottom plate that accommodates the cell stack and has a gas venting hole positioned at the bottom of the cell stack; and A battery module characterized by comprising a venting induction unit having a needle member configured to protrude from the gas venting hole and make a hole in the battery cell, and a needle stopper member configured to prevent the needle member from protruding while deformation does not occur due to heat or external force.

2. In paragraph 1, A battery module characterized in that the needle stopper member is made of a material that can be heat melted at a predetermined temperature.

3. In paragraph 1, A battery module characterized in that the needle stopper member has a notch line so as to be broken by a predetermined pressure.

4. In paragraph 1, The above needle member, An elastic member vertically arranged in the above gas venting hole; A needle portion coupled to the upper end of the elastic member; and A battery module characterized by including an elastic fixing member coupled to the lower end of the elastic member and fixed to the bottom plate of the module case.

5. In paragraph 4, The above needle stopper member, A blocking portion that blocks the needle portion at the upper portion of the gas venting hole; and; A battery module characterized by including a stopper fixing part connected to the blocking part and fixed to the bottom plate of the module case.

6. In paragraph 5, A battery module characterized in that a notch line is provided at the boundary between the blocking portion and the stopper fixing portion.

7. In paragraph 5, A battery module characterized in that at least one of the blocking portion and the stopper fixing portion is made of a heat-meltable resin material.

8. In paragraph 5, The above needle part, A needle plate coupled to the upper end of the elastic member and positioned below the blocking portion; and A battery module characterized by comprising one or more needles protruding from the needle plate.

9. In paragraph 8, A battery module characterized in that the one or more needles are configured to be embedded inside the blocking portion.

10. In paragraph 1, The above battery cells are pouch-type battery cells, The above gas venting holes are provided at regular intervals along the width direction of the bottom plate, A battery module characterized in that the gas venting hole is provided at a position corresponding vertically to a cell terrace formed by heat-melting a pouch sheet in the pouch-type battery cell.

11. In paragraph 10, The above venting induction unit is provided in each of the above gas venting holes, A battery module characterized in that the gas venting hole and the venting induction unit are provided on the front and rear sides of the bottom plate of the module case.

12. In paragraph 1, The above module case is, A top plate covering the upper portion of the above cell stack; A bottom plate covering the lower part of the above cell stack; A pair of side plates each covering both side surfaces of the cell stack; and A battery module characterized by comprising a pair of end covers each covering the front and rear of the cell stack.

13. In paragraph 1, Busbars electrically connected to the electrode leads provided in the above battery cells; and Further comprising a busbar frame that supports the busbars and has a lead slot through which the electrode leads can pass, and is mounted on the front or rear portion of the cell stack; A battery module characterized in that the busbars include a first busbar and a second busbar that are arranged to overlap each other with the electrode lead therebetween, and the electrode lead is press-fitted between the first busbar and the second busbar.

14. In paragraph 13, The above battery cells are pouch-type battery cells, and each wide surface is erected and stacked in one direction. The cell stack includes a plurality of barrier plates interposed between the battery cells at predetermined intervals along the one direction to limit the movement of heat or gas between the battery cells, A battery module characterized in that each of the plurality of barrier plates is fitted and connected at the end to the busbar frame so that the battery cells and the gas venting holes are divided into a predetermined number of units.

15. A battery pack comprising a battery module according to any one of claims 1 to 14.

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