Battery module, and battery pack containing the same.

Abstract

The battery module according to the present invention includes a cell stack consisting of stacked battery cells, a module case housing the cell stack and having a gas vent hole in a bottom plate located below the cell stack, and a vent guide unit comprising a needle member configured to protrude from the gas vent hole to create a hole in the battery cell, and a needle stopper member configured to prevent the needle member from protruding when not deformed by heat or external force.

Description

Technical Field

[0001] The present invention relates to a battery module and a battery pack including the same, and more specifically, to a battery module excellent in safety against thermal events and the like, and a battery pack including the same.

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

Background Art

[0003] With the significant increase in technology development and demand for various mobile devices, electric vehicles, energy storage systems (ESS), etc., the interest and demand for secondary batteries as an energy source have been rapidly increasing. Conventionally, nickel cadmium batteries or nickel metal hydride batteries have been widely used as secondary batteries, but recently, lithium secondary batteries have been widely used because they have almost no memory effect compared to nickel-based secondary batteries, are free from charging and discharging, have a very low self-discharge rate, and have a high energy density.

[0004] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as the positive electrode active material and the negative electrode active material, respectively. A lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate coated with such a positive electrode active material and a negative electrode active material are arranged with a separator interposed therebetween, and an exterior material that hermetically stores the electrode assembly together with an electrolytic solution, that is, a battery case.

[0005] Generally, secondary batteries are 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 according to the shape of the exterior material.

[0006] Lithium-ion batteries, which are widely used today, have an operating voltage of approximately 2.5V to 4.5V per unit. Therefore, in the case of electric vehicles and power storage devices that require large capacity and high output, battery modules or battery packs are constructed by connecting multiple lithium-ion batteries in series and / or parallel, and these are used as the energy source. In particular, to meet the output and capacity requirements of electric vehicles, battery modules and battery packs contain a very large number of lithium-ion batteries.

[0007] Therefore, battery modules and battery packs require measures to prevent fires or reduce their spread in the event of a thermal event.

[0008] For example, if a thermal event occurs in a battery module, and gas or flames are generated, causing heat to accumulate inside, heat can rapidly propagate between battery cells (thermal propagation). As a result, multiple battery cells may ignite simultaneously, making it difficult to suppress the thermal event, and the battery module may explode, potentially exacerbating the damage.

[0009] Therefore, when a thermal event occurs in the battery module, there is a need for a method that can effectively dissipate thermal energy from within the battery module in order to delay the propagation of thermal runaway and ignition between battery cells as much as possible. [Overview of the project] [Problems that the invention aims to solve]

[0010] The present invention was made to solve the above-mentioned technical problems, and one of its objectives is to provide a battery module that can effectively dissipate heat and pressure inside the battery module when a thermal event occurs in the battery module.

[0011] The technical problems that this invention aims to solve are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0012] A battery module according to one aspect of the present invention includes a cell stack consisting of stacked battery cells, a module case housing the cell stack and having gas vent holes in its bottom plate, and a vent guide unit comprising a needle member configured to protrude from the gas vent holes to create holes in the battery cells, and a needle stopper member configured to prevent the needle member from protruding when not deformed by heat or external force.

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

[0014] The needle stopper member may have a notch line so as to break under a predetermined pressure.

[0015] The needle member may include an elastic member positioned perpendicular to the gas vent hole, a needle portion coupled to the upper end of the elastic member, and an elastic fixing portion coupled to the lower end of the elastic member and fixed to the bottom plate of the module case.

[0016] The needle stopper member may include a blocking portion that blocks the needle portion above the gas vent 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 blocking portion and the stopper fixing portion.

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

[0019] The needle portion may include a needle plate connected to the upper end of the elastic member and located below the blocking portion, and one or more needles protruding from the needle plate.

[0020] One or more of the needles may be configured to be embedded inside the blocking portion.

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

[0022] The vent guide unit is provided in each of the gas vent holes, and the gas vent holes and the vent guide unit may 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 that covers the upper part of the cell stack, a bottom plate that covers the lower part of the cell stack, a pair of side plates that cover both sides of the cell stack, and a pair of end covers that cover the front and rear of the cell stack, respectively.

[0024] The invention further includes a busbar electrically connected to electrode leads provided in the battery cell, and a busbar frame that supports the busbar and has lead slots through which the electrode leads can pass, and is attached to the front or rear of the cell stack, wherein the busbar includes a first busbar and a second busbar arranged to overlap with respect to the electrode leads, and the electrode leads can be crimped and fixed between the first busbar and the second busbar.

[0025] The battery cells are pouch-type battery cells, with their wide faces standing upright and stacked in one direction. The cell stack includes a plurality of barrier plates inserted between the battery cells at predetermined intervals along the one direction to limit the transfer of heat or gas between the battery cells. Each of the plurality of barrier plates can be configured such that its end portion is fitted into the bus bar frame so that the battery cells and the gas vent holes are partitioned 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.

Advantages of the Invention

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

[0028] In particular, according to the vent guiding unit of the present invention, holes can be formed in the trigger battery cell with signs of thermal abnormality, so that high-temperature gas, particles, etc. can be quickly discharged from the trigger battery cell to the outside of the module case under a low-pressure situation. Thereby, heat damage to adjacent battery cells can be reduced.

[0029] In addition, the present invention can have various other effects, which will be described in each embodiment or the description thereof will be omitted for effects that can be easily inferred by those skilled in the art.

Brief Description of the Drawings

[0030] [Figure 1] It is a schematic perspective view of a battery module according to an embodiment of the present invention. [Figure 2] It is an exploded perspective view of the battery module of FIG. 1. [Figure 3] It is a perspective view showing the cell stack of FIG. 2. [Figure 4] This is a perspective view showing a portion of a module case relating to one embodiment of the present invention. [Figure 5] This is a magnified view of a portion of Figure 4. [Figure 6] This is a perspective view showing the configuration of a vent induction unit according to one embodiment of the present invention. [Figure 7] This figure shows an example of the application of a vent induction unit applied to a gas vent hole in a battery module according to one embodiment of the present invention. [Figure 8] This is a schematic cross-sectional view of a battery module according to one embodiment of the present invention. [Figure 9] This is an enlarged view of area A in Figure 8. [Figure 10] This diagram corresponds to Figure 9 and shows an example where the needle stopper member has broken and the needle portion has popped out of the gas vent hole. [Figure 11] This figure illustrates an example of assembly between a cell laminate and a busbar frame according to one embodiment of the present invention. [Figure 12] This figure shows a busbar frame in which the frame cover and crimped busbar shown in Figure 11 are joined together. [Figure 13] This is a schematic cross-sectional view of an assembled cell stack and a busbar frame according to one embodiment of the present invention. [Figure 14] This diagram schematically shows an automobile including a battery pack according to one embodiment of the present invention. [Modes for carrying out the invention]

[0031] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims are not to be interpreted in their usual and dictionary sense, but rather in accordance with the technical ideas of the present invention, in accordance with the principle that the inventor himself may appropriately define the concepts of terms in order to best describe the invention. Therefore, it should be understood that the configurations shown in the embodiments described herein represent only one of the most preferred embodiments of the present invention and do not represent the entirety of the technical ideas of the present invention, and that there may be a variety of equivalents and modifications that can be substituted for them at the time of this application.

[0032] In the drawings, the size of each component or specific part of that component is exaggerated, omitted, or schematic for the sake of clarity and ease of explanation. Therefore, the size of each component does not fully reflect its actual size. Where a specific description of a relevant known function or configuration is deemed to unnecessarily obscure the gist of the invention, such description is omitted.

[0033] Figure 1 is a schematic perspective view of a battery module according to one embodiment of the present invention, Figure 2 is an exploded perspective view of the battery module of Figure 1, Figure 3 is a perspective view showing the cell stack of Figure 2, and Figure 4 is a perspective view showing a part of the module case according to one embodiment of the present invention.

[0034] Referring to Figures 1 to 4, a battery module 10 according to one embodiment of the present invention includes a cell stack 100 consisting of stacked battery cells 110, a module case 200 that houses the cell stack 100 and has a gas vent hole 201 in its bottom plate 220, and a vent guide unit 300 that is positioned in the gas vent hole 201.

[0035] As shown in Figures 2 and 3, the cell stack 100 is formed by stacking a plurality of battery cells 110 vertically in a horizontal direction. The battery cells 110 in this embodiment are pouch-type battery cells 110. Each of the pouch-type battery cells 110 can be stacked in one direction with its wide surface upright. The pouch-type battery cell 110 includes electrode leads 111, an electrode assembly and electrolyte, and a pouch case that seals and houses the electrode assembly and electrolyte.

[0036] The pouch case is composed of two pouch sheets, at least one of which can have a recessed groove. The electrode assembly and 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, the portion of the pouch sheet sealed by heat-sealing is called the seal portion. One end of the electrode lead 111 is connected to the electrode assembly inside the pouch case, and the other end protrudes outside the pouch case, with a portion between the one end and the other end fixed within the seal portion when the pouch sheet is heat-sealed. The portion of the electrode lead 111 exposed outside the pouch case can function as an electrode terminal of the pouch-type battery cell 110.

[0037] For reference, a pouch-type battery cell 110 in which the electrode assembly is packaged in two pouch sheets has four sealing portions. Here, the four sealing portions refer to the front sealing portion on which the electrode leads 111 protrude, the rear sealing portion, and two side sealing portions extending in the longitudinal direction of the electrode assembly. On the other hand, a pouch-type battery cell 110 in which the electrode assembly is packaged by folding a single pouch sheet has three sealing portions. Here, the three sealing portions refer to the front sealing portion on which the electrode leads 111 protrude, the rear sealing portion, 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.

[0038] On the other hand, the cell stack 100 according to this 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.

[0039] Referring to Figures 1 and 2, the module case 200 may consist of a case body and a pair of end covers 250 and 260.

[0040] The case body may include a top plate 210 that covers the upper part of the cell stack 100, a bottom plate 220 that covers the lower part of the cell stack 100, and a pair of side plates 230 and 240 that cover both sides of the cell stack 100, respectively.

[0041] The bottom plate 220 and the pair of side plates 230, 240 can be formed integrally. The bottom plate 220 and the pair of side plates 230, 240 provided integrally are sometimes called a U-frame. The U-frame and the top plate 210 can be joined by methods such as bolting, welding, or bonding. On the other hand, unlike this embodiment, the top plate 210, the bottom plate 220, and the pair of side plates 230, 240 can also be formed integrally in a rectangular tubular shape. The end covers 250, 260 are open in the case body and can be joined at the front and rear.

[0042] In this embodiment, referring to Figures 1 and 2, the top plate 210 may have terminal through-holes that allow the terminal busbars of the battery module 10 to be pulled upward. The terminal busbars include a positive terminal busbar 410a and a negative terminal busbar 410b. However, unlike in this embodiment, the terminal busbars may also be redesigned to, for example, pass through the end cover 250 and extend forward.

[0043] A thermal resin TR can 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 enhances the fixation of the battery cells 110 to the bottom plate 220. The battery cells 110 are provided in a configuration in which a wide surface is raised and stacked in the width direction of the bottom plate 220. In this case, the lower edge surface of all battery cells 110 can be in contact with the thermal resin TR. Therefore, in each battery cell 110, heat is transferred to the bottom plate 220 via the thermal resin TR, allowing the heat from the battery cells 110 to be efficiently dissipated to the outside during charging and discharging.

[0044] Referring again to Figure 2 or Figure 4, the bottom plate 220 has a gas vent hole 201. The gas vent hole 201 prevents a pressure difference from occurring between the inside and outside of the module case 200 under normal circumstances, and prevents excessive heat buildup inside the battery module 10 by venting high-temperature gases ejected from the battery cells 110 to the outside when a thermal event occurs. In addition, gas can be vented to the outside through the gas vent hole 201, preventing collapse or explosion of the battery module 10 due to a rapid increase in internal pressure.

[0045] The gas vent hole 201 may be provided in the lower region of the cell terrace 112 of the battery cell 110.

[0046] Specifically, as shown in Figure 2, the gas vent holes 201 according to this embodiment may be provided at predetermined intervals along the width direction of the bottom plate 220. When the cell stack 100 is housed in the module case 200, the gas vent holes may be provided in positions corresponding vertically to the cell terraces 112 of the pouch-type battery cell 110. The pouch-type battery cell 110 in this embodiment has two cell terraces 112, one at the front and one at the rear. Corresponding to the structure of such a pouch-type battery cell 110, the gas vent holes 201 according to this embodiment may be configured on the front and rear sides of the bottom plate 220 of the module case 200, respectively.

[0047] In other words, a plurality of gas vent holes 201 can be provided in the bottom plate 220, corresponding to the number and position of the cell terraces 112 of the pouch-type battery cell 110. There are a plurality of gas vent holes 201, and they can be provided at regular intervals along the width direction (X direction) of the bottom plate 220, near both ends along the length direction (Y direction).

[0048] Furthermore, as shown in Figure 2, the thermal resin can be configured to be distributed to the bottom plate 220 only up to a position adjacent to the gas vent hole 201, so that the gas vent hole 201 is not blocked.

[0049] Preferably, the gas vent hole 201 may be configured in the pouch-type battery cell 110 at a position corresponding vertically to the cell terrace 112.

[0050] Secondary batteries may generate gas as a side reaction during charging and discharging. In particular, if a large amount of gas is generated during overcharging and discharging, causing a large increase in internal pressure, a swelling phenomenon may occur. If this worsens, the bonding strength of the heat-fused seal may decrease, potentially causing that part to rupture and release gas. At this time, among the sealing parts of the pouch-type battery cell 110, the cell terrace 112 has electrode leads 111 interposed therein, so relatively more heat is generated than in other parts, resulting in lower bonding strength. Consequently, the cell terrace 112 is the most likely part of the pouch-type battery cell 110 to be damaged when the internal pressure rises.

[0051] Therefore, in the battery module 10 according to one embodiment of the present invention, gas vent holes 201 are provided in the side edge regions of the bottom plate 220 that correspond to the cell terrace 112 and above and below, so that gases and other substances ejected when the cell terrace 112 is damaged can be directly discharged to the outside of the battery module 10.

[0052] With the above configuration, for example, when a high-temperature gas is ejected from a trigger battery cell 110 where a thermal event has occurred, it becomes easy to discharge the high-temperature gas towards the bottom of the module case 200 through the gas vent hole 201. In this case, it is possible to prevent other battery cells 110 adjacent to the trigger battery cell 110 from suffering significant thermal damage. In addition, a large amount of gas can be quickly discharged to the outside of the battery module 10, preventing the phenomenon of a rapid increase in the internal pressure of the battery module 10.

[0053] On the other hand, a battery module 10 according to one embodiment of the present invention may include a vent guide unit 300 comprising a needle member 310 configured to protrude from the gas vent hole 201 and create a hole in the battery cell 110, and a needle stopper member 320 configured to prevent the needle member 310 from protruding when it is not deformed by heat or external force.

[0054] The vent guide unit 300 may be provided for each of the gas vent holes 201, as shown in Figures 2 and 4. The gas vent holes 201 and the vent guide unit 300 may be provided on the front and rear sides of the bottom plate 220 of the module case 200.

[0055] As will be explained in detail below, in the battery module 10 according to the present invention, since the vent induction unit 300 is provided in the gas vent hole 201, when a thermal event occurs, it can create a hole in the cell terrace 112 of the battery cell 110 and expel thermal energy from inside the battery cell 110 at an early stage through the hole.

[0056] Referring mainly to Figures 4 to 7, the main components of the vent guidance unit 300 are examined, and the vent guidance unit 300 includes a needle member 310 and a needle stopper member 320.

[0057] First, the needle member 310 is a component that induces cracks or holes in the pouch case of the battery cell 110 when it overheats during charging and discharging, thereby guiding the discharge of gases and other substances from inside the battery cell 110. In particular, the battery module 10 of the present invention is configured such that when a thermal event occurs, the needle member 310 damages a specific part of the battery cell 110, allowing high-temperature gases and other substances to be discharged from inside the battery cell 110 in a specific direction.

[0058] For example, the battery module 10 of the present invention may be configured such that the needle member 310 pops out of the gas vent hole 201 to puncture or damage the cell terrace 112 region of the battery cell 110 when a thermal event occurs. With this configuration, for example, if the needle member 310 pops out from the bottom of the cell terrace 112 while gas has been collected in the cell terrace 112, a hole is formed in the cell terrace 112, and at this time, gas is discharged from inside the battery cell 110 and can be directionally vented toward the bottom of the bottom plate 220 via the gas vent hole 201. On the other hand, even if the needle member 310 pops out when the cell terrace 112 is not expanded, when the cell terrace 112 region expands later, the needle member 310 may rupture or enlarge the cell terrace 112, allowing for concentrated gas discharge to the outside in the cell terrace 112 region.

[0059] Specifically, the needle member 310 may include an elastic member 311 positioned perpendicular to the gas vent hole 201, a needle portion 312 connected to the upper end of the elastic member 311, and an elastic fixing portion 313 connected to the lower end of the elastic member 311 and fixed to the bottom plate 220 of the module case 200.

[0060] In this embodiment, a compression spring is used as the elastic member 311. However, instead of the compression spring, any compressible and expandable structure, such as elastic rubber or bellows, can be used as the elastic member 311.

[0061] The 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.

[0062] The needle plate 312a is preferably made of a material with excellent heat resistance and may be provided in the form of a plate. The needle plate 312a and the compression spring can be joined, for example, by welding or adhesive bonding.

[0063] The needle 312b has a tip. For example, the needle 312b may be conical, rod-shaped, pin-shaped, or the like, as long as it has a tip that can form a hole in the pouch case. The needle 312b may be formed integrally with the needle plate 312a, or it may be provided in a structure that allows it to be attached to or detached from the needle plate 312a.

[0064] The needle 312b may be one or more. For example, as in this embodiment, if the needle 312b is composed of multiple needles, multiple holes can be formed in the cell terrace 112. Also, as in this embodiment, in the case of a cell stack 100 composed of multiple battery cells 110 stacked horizontally, the cell terraces 112 of adjacent battery cells 110 may expand simultaneously due to heat propagation. In this case, if the cell terraces 112 of adjacent battery cells 110 are located in the upper region of the multiple needles 312b, holes can be formed in all of the cell terraces 112.

[0065] The elastic fixing portion 313 is preferably made of a material with excellent heat resistance and may be provided in the form of a plate. The elastic fixing portion 313 and the compression spring can be joined, for example, by welding or adhesive bonding.

[0066] In this embodiment, the elastic fixing portion 313 can be attached to the lower surface of the bottom plate 220. For example, as shown in Figure 7, the elastic fixing portion 313 is located below the gas vent hole 201, and both ends can be welded or adhesively bonded to the bottom plate 220 of the module case 200. In this case, the compression spring may be configured to be positioned perpendicular to the interior of the gas vent hole 201 at the center of the elastic fixing portion 313. On the other hand, unlike this embodiment, the elastic fixing portion 313 can be formed integrally with the bottom plate 220 of the module case 200.

[0067] The elastic fixing portion 313 positions the compression spring within the gas vent hole 201, allowing it to be compressed by the needle stopper member 320.

[0068] Referring to Figures 5 and 6, the needle stopper member 320 may include a blocking portion 321 that blocks the needle portion 312 above the gas vent 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.

[0069] The stopper fixing portion 323 can be fixedly coupled to the upper surface of the bottom plate 220 of the module case 200 at least at one end. For example, in this embodiment, the stopper fixing portion 323 may be provided in a form that extends from one side and the other side of the blocking portion 321 and can be attached to the upper surface of the module case 200. Various methods can be used to fix the stopper fixing portion 323 to the bottom plate 220 of the module case 200, such as welding, bonding, and fastening with hooks.

[0070] The blocking portion 321 may be positioned vertically above the needle plate 312a. For example, the blocking portion 321 may be positioned opposite the needle plate 312a so as to prevent the needle plate 312a from being ejected by the compression spring. In this case, one or more needles 312b may be configured to be embedded inside the blocking portion 321. Although not shown in detail in the drawings, the blocking portion 321 may have holes into which the needles 312b can be inserted.

[0071] Furthermore, the blocking portion 321 is integrally formed with the stopper fixing portion 323, which is fixed to the upper surface of the bottom plate 220 of the module case 200. Therefore, even if the blocking portion 321 is subjected to an external force from the compression spring, a reaction force is generated in the blocking portion 321, preventing the needle plate 312a from flying out.

[0072] The needle stopper member 320, which consists of the blocking portion 321 and the stopper fixing portion 323 as described above, can be made of 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 break under a predetermined pressure.

[0073] With the above configuration, under normal circumstances, the needle portion 312 cannot escape from the gas vent hole 201 because it is blocked by the needle stopper member 320. However, if the needle stopper member 320 is damaged by external pressure or melted by heat, causing it to detach from the bottom plate 220 of the module case 200 or partially melt and disappear, the needle portion 312 can escape from the gas vent hole 201. At this time, the needle portion 312 can form cracks or holes in the pouch case of the battery cell 110. This allows gas and thermal energy inside the battery cell 110 to be quickly discharged to the outside through the gas vent hole 201. In other words, high-temperature gas and high-temperature particles generated in the battery cell 110 where an event has occurred are discharged to the outside from the module case 200 through the gas vent hole 201 via the shortest path, thus minimizing heat accumulation inside the module case 200 and thermal runaway propagation between battery cells 110.

[0074] At least one of the blocking portion 321 and the stopper fixing portion 323 constituting the needle stopper member 320 may be formed from a heat-meltable resin material, while the other may be formed from a heat-resistant metal material. For example, the blocking portion 321 may be made from expanded polystyrene, rubber, or plastic, and the stopper fixing portion 323 may be made from a metal material such as aluminum, copper, or steel.

[0075] With the needle stopper member 320 configured in this way, the heat generated in the battery cell 110 is absorbed by the stopper fixing portion 323 via 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 transferred to the blocking portion 321. As a result, the blocking portion 321 melts and falls off the stopper fixing portion 323, and at this time, the needle portion 312 can be ejected from the gas vent hole 201 by the elastic force of the compression spring.

[0076] The needle stopper member 320 may be designed such that when an external force exceeding a certain strength is applied along with heat, the boundary between the blocking portion 321 and the stopper fixing portion 323 is destroyed. For this reason, the needle stopper member 320 according to this embodiment is provided with 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 recessed to a predetermined height from the surface of the needle stopper member 320 and continues intermittently or continuously in the width direction. In such a needle stopper member 320, the notch line 322 portion is damaged by an increase in the internal pressure of the module case 200 or by the wind pressure of the gas discharged to the gas vent hole 201, and the blocking portion 321 and the stopper fixing portion 323 can be separated. In other words, the needle stopper member 320 can also have the blocking portion 321 detach from the stopper fixing portion 323 due to pressure rather than heat.

[0077] Figure 8 is a schematic cross-sectional view of a battery module 10 according to one embodiment of the present invention, Figure 9 is an enlarged view of area A in Figure 8, and Figure 10 is a diagram corresponding to Figure 9, showing an example in which the needle stopper member 320 is damaged and the needle portion 312 has popped out of the gas vent hole 201.

[0078] Below, with reference to Figures 8 to 10, a brief explanation of the operation of the vent induction unit 300 according to one embodiment of the present invention will be given.

[0079] As shown in Figure 8, the battery module 10 according to one embodiment of the present invention has gas vent holes 201 provided on the front and rear sides of the bottom plate 220 of the module case 200. Here, the front and rear sides of the bottom plate 220 of the module case 200 refer to the positions corresponding to the lower part of the front cell terrace 112 and the lower part of the rear cell terrace 112 of the battery cell 110.

[0080] Furthermore, as shown in Figure 9, the battery module 10 includes a vent guide unit 300 provided in the gas vent hole 201. As described above, as long as 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 will not fly out of the gas vent hole 201. In other words, as long as no thermal event occurs inside the battery module 10, the needle portion 312 will not fly out of the gas vent hole 201 and damage the battery cell 110.

[0081] However, if the temperature of the battery cell 110 rises rapidly, for example due to a short circuit in the battery cell 110, thermal deformation may occur in the needle stopper member 320. In this case, there can be various paths through which heat is transferred from the battery cell 110 to the needle stopper member 320. For example, as shown by "H1" in Figure 9, heat can be transferred from the battery cell 110 to the stopper fixing part 323 via the thermal resin TR and the bottom plate 220 of the module case 200. Also, if gas is generated inside the battery cell 110 and the cell terrace 112 expands, and the blocking part 321 of the needle stopper member 320 receives heat and pressure from the expanded cell terrace 112, as shown by "H2", the blocking part 321 may melt or the notch line 322 may rupture.

[0082] Thus, when deformation occurs in the needle stopper member 320 due to heat or external force, as shown in Figure 10, the elastic force of the compression spring 311 becomes greater than the reaction force of the blocking portion 321, causing the compression spring 311 to push the needle portion 312 upward onto the gas vent hole 201. As a result, the needle 312b that has protruded above the gas vent hole 201 can create a hole or crack in the cell terrace 112. Consequently, high-temperature gases, particles, etc., from the battery cell 110 can be effectively directionally vented to the outside through the gas vent hole 201 of the module case 200 at an early stage. Therefore, according to the vent induction unit 300 of the present invention, it is possible to prevent the accumulation of heat and pressure inside the battery module 10 and to significantly delay thermal runaway of the battery module 10.

[0083] Figure 11 is a diagram illustrating an assembly example of a cell laminate 100 and a busbar frame 400 according to one embodiment of the present invention, Figure 12 is a diagram showing a busbar frame 400 in which the frame cover 500 and crimp busbars of Figure 11 are joined, and Figure 13 is a schematic cross-sectional view of the cell laminate 100 and busbar frame 400 assembled together according to one embodiment of the present invention.

[0084] Referring to Figures 2 and 11 to 13, a battery module 10 according to one embodiment of the present invention may further include a plurality of busbars 410, 600, a busbar frame 400, a frame cover 500, and a contact cover 700 that are electrically connected to the electrode leads 111 provided on the battery cell 110.

[0085] The busbars 410 and 600 can be formed from an electrically conductive metal such as copper or aluminum and provided in a rod shape.

[0086] The busbar frame 400 can be provided in a plate shape that supports the busbars 410 and 600 while covering the front and rear portions of the cell stack 100, respectively. The busbar frame 400 can be made of an electrically insulating material such as plastic. The busbar frame 400 can also be provided with lead slots 420 through which the electrode leads 111 can pass. The electrode leads 111 of the battery cell 110 can pass through the lead slots 420 and be attached to the busbar in a predetermined pattern.

[0087] In particular, the battery module 10 of this embodiment is configured so that the electrode leads 111 can be fixed to the busbar by crimping them to the busbar without welding them to the busbar. Therefore, the assembly time with the battery module 10 is shortened, and the assembly process can be made easier.

[0088] In more detail, the busbar according to one embodiment of the present invention includes a first busbar 410 and a second busbar 600. Referring to Figures 11 and 12, the first busbar 410 and the second busbar 600 may be arranged to overlap with the electrode lead 111 in between. The electrode lead 111 may also be crimped and fixed between the first busbar 410 and the second busbar 600. In this case, by fastening the first busbar 410 and the second busbar 600 using fastening members 800 such as bolts, the state in which the electrode lead 111 is crimped between the first busbar 410 and the second busbar 600 can be stably maintained.

[0089] The frame cover 500 is made of a material with low thermal conductivity and excellent heat resistance, and is provided in the form of a pad made of, for example, silicone, aerogel, or mica material, and can be bonded to the busbar frame 400 facing it, as shown in Figure 12. The frame cover 500 may include a plurality of cover plates 510. Each cover plate 510 may be provided so as to correspond to a partition wall 430 protruding from the busbar frame 400 and a section of the busbar frame 400 partitioned by the end portion 121 of a barrier plate 120, which will be described later. Here, the partition wall 430 and the end portion 121 of the barrier plate 120 can serve to prevent short circuits between the electrode leads 111.

[0090] When the frame cover 500 is attached to the busbar frame 400, it can cover the lead slots 420 of the busbar frame 400. With this configuration, when a thermal event occurs, it is possible to prevent high-temperature gases or flames from leaking out to the front or rear of the cell stack 100 through the lead slots 420.

[0091] The electrode lead 111 is bent according to a predetermined pattern and positioned on the front of the corresponding first bus bar 410, after which the frame cover 500 can be attached to the bus bar frame 400. Here, the frame cover 500 has bus bar insertion holes H. The second bus bar 600 may be configured to connect with the first bus bar 410 via the bus bar insertion holes H, sandwiching the electrode lead 111.

[0092] The contact cover 700 is a component that brings the frame cover 500 into close contact with the busbar frame 400, and also brings the second busbar 600 into close contact with the electrode lead 111 and the first busbar 410.

[0093] The contact cover 700 may be composed of a plurality of contact plates 710, as shown in Figure 12. The number of contact plates 710 is provided to correspond to the number of busbars, and each contact plate 710 can be coupled to each corresponding busbar so as to be fixed to each other by fastening members 800. The contact plates 710 may also be attached between the end portion 121 of the barrier plate 120 that penetrates the busbar frame 400 and the partition wall 430 that protrudes from the busbar frame 400. The contact plates 710 may be made of a material that has high mechanical rigidity and flame retardant properties. For example, the contact plates 710 may be made of a rigid material with a high melting point such as SUS that has been insulated, or they may be made of a rigid material with fire-resistant and insulating properties.

[0094] As described above, a cell stack 100 according to one embodiment of the present invention may include a plurality of barrier plates 120 inserted between battery cells 110 at predetermined intervals along one direction to restrict the movement of heat or gas between the battery cells 110.

[0095] Each of the multiple barrier plates 120 can be fitted to the busbar frame 400 at its end portion 121, such that the battery cells 110 and the gas vent holes 201 are divided into a predetermined number of units, as shown in Figures 12 and 13.

[0096] The barrier plate 120 has the form of a compressible pad and can be made of a material with excellent heat resistance and / or fire resistance, such as silicone, aerogel, or mica.

[0097] As shown in Figure 13, such a barrier plate 120 can perform a thermal barrier function that blocks hot air, such as flames generated in a ignited battery cell 110, from advancing in the stacking direction of the battery cells 110. Therefore, heat propagation to adjacent battery cells 110 can be minimized. The barrier plate 120 can block not only heat but also high-temperature gases, flames, and ejecta generated in the battery cells 110. As a result, the barrier member can partition or separate the battery cells 110 and prevent flames and other substances from transferring between the battery cells 110.

[0098] On the other hand, the 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 the charging and discharging of one or more battery modules 10, a current sensor, a fuse, and a pack case for housing the above-described components.

[0099] Referring to Figure 14, the battery pack 2 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 electrical energy source to drive the vehicle 1 by providing driving force to the motor. The battery pack can be charged and discharged by an inverter in response to the drive of the motor and / or internal combustion engine. The battery pack can be charged by a regenerative charging device coupled to the brake. The battery pack can be electrically connected to the motor of the vehicle via an inverter.

[0100] Although the present invention has been described above with reference to limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and various modifications and variations are possible within the equivalent scope of the technical idea of ​​the present invention and the claims described below by persons with ordinary skill in the art to which the present invention pertains.

[0101] Furthermore, while terms indicating directions such as up, down, left, right, front, and back are used in this specification, such terms are for explanatory convenience and can change depending on the position of the object in question, the observer's position, etc., as will be apparent to those skilled in the art. [Explanation of Symbols]

[0102] 1. Automobile 2 Battery Packs 10 Battery Modules 100-cell stack 110 battery cells 111 Electrode Leads 112 Cell Terrace 120 Barrier Plate 121 Terminal part 200 Module Case 201 Gas Vent Hall 210 Top Plate 220 Bottom Plate 230 Side Plate 240 Side Plate 250 End Cover 260 End Cover 300 Vent Induction Unit 310 Needle component 311 Elastic members 312 Needle section 312a Needle Plate 312b Needle 313 Elastic body fixing part 320 Needle stopper component 321 Blocking section 322 Notch lines 323 Stopper fixing part 400 Busbar Frame 410 First Bus Bar 410a Positive terminal busbar 410b Negative terminal bus bar 420 lead slots 430 Bulkhead 500 Frame Cover 510 Cover Plate 600 Second Bus Bar 700 Close-fitting cover 710 Contact Plate 800 Fastening members H Busbar insertion hole TR Thermal Resin

Claims

1. A cell stack consisting of stacked battery cells, A module case that houses the cell stack and has a gas vent hole in the bottom plate located below the cell stack, A battery module comprising a vent guide unit having a needle member configured to protrude from the gas vent hole and create a hole in the battery cell, and a needle stopper member configured to prevent the needle member from protruding when it is not deformed by heat or external force.

2. The battery module according to claim 1, wherein the needle stopper member is made of a material that can be heat-melted at a predetermined temperature.

3. The battery module according to claim 1 or 2, wherein the needle stopper member has a notch line so as to break upon a predetermined pressure.

4. The needle member is An elastic member positioned perpendicular to the gas vent hole, A needle portion is coupled to the upper end of the elastic member, The battery module according to claim 1 or 2, further comprising an elastic fixing portion coupled to the lower end of the elastic member and fixed to the bottom plate of the module case.

5. The needle stopper member is, A blocking portion that blocks the needle portion at the upper part of the gas vent hole, The battery module according to claim 4, further comprising: a stopper fixing portion connected to the blocking portion and fixed to the bottom plate of the module case.

6. The battery module according to claim 5, wherein a notch line is provided at the boundary between the blocking portion and the stopper fixing portion.

7. The battery module according to claim 5, wherein at least one of the blocking portion and the stopper fixing portion is made of a heat-meltable resin material.

8. The needle portion is, A needle plate is connected to the upper end of the elastic member and located below the blocking portion, The battery module according to claim 5, further comprising one or more needles protruding from the needle plate.

9. The battery module according to claim 8, wherein one or more of the needles are configured to be embedded inside the blocking portion.

10. The aforementioned battery cell is a pouch-type battery cell. The gas vent holes are provided at predetermined intervals along the width direction of the bottom plate. The battery module according to claim 1 or 2, wherein the gas vent holes are provided in the pouch-type battery cell at positions corresponding to the cell terraces formed by heat-sealing the pouch sheet.

11. The venting units are provided in each of the gas vent holes, The battery module according to claim 10, wherein the gas vent hole and the vent guide unit are provided on the front and rear sides of the bottom plate of the module case.

12. The aforementioned module case is A top plate covering the upper part of the cell stack, The bottom plate covers the lower part of the cell stack, A pair of side plates that cover both sides of the cell stack, The battery module according to claim 1 or 2, further comprising a pair of end covers that cover the front and rear of the cell stack, respectively.

13. A busbar electrically connected to electrode leads provided in the aforementioned battery cell, The present invention further includes a busbar frame that supports the busbar and has lead slots through which the electrode leads can pass, and is attached to the front or rear portion of the cell stack, The battery module according to claim 1 or 2, wherein the busbars include a first busbar and a second busbar arranged to overlap with the electrode leads in between, and the electrode leads are crimped and fixed between the first busbar and the second busbar.

14. The aforementioned battery cells are pouch-type battery cells, each with its wide surface facing upright and stacked in one direction. The cell stack includes a plurality of barrier plates inserted between the battery cells at predetermined intervals along the one direction to restrict the movement of heat or gas between the battery cells. The battery module according to claim 13, wherein each of the plurality of barrier plates has its end portion fitted into the busbar frame such that the battery cells and gas vent holes are divided into a predetermined number of units.

15. A battery pack comprising the battery module described in claim 1 or 2.

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