Ventilation device for pouch-type secondary battery, and battery module including the same

Abstract

A vent mechanism for a pouch-type secondary battery according to embodiments of the present invention comprises: a frame including a first frame and a second frame; and a connecting portion connecting the first frame and the second frame and having a slit formed therein, wherein at least one of the first frame and the second frame includes a vent guide portion formed by being recessed on a surface facing the other, and a vent control portion connected to the vent guide portion may be formed as a space formed between the first frame and the second frame. Accordingly, even if internal pressure exceeding an appropriate level is generated by gas inside the pouch during operation of the lithium secondary battery, the vent can be guided in a certain direction to exhaust, thereby controlling the generation of the vent.

Description

Technology Field

[0001] The present invention relates to a vent mechanism for a pouch-type secondary battery and a battery module including the same. Background Technology

[0002] Rechargeable batteries are batteries capable of repeated charging and discharging, and with the advancement of the information and communication and display industries, they are widely applied as power sources for portable electronic communication devices such as camcorders, mobile phones, and laptop PCs. Furthermore, recently, battery packs containing rechargeable batteries are being developed and applied as power sources for eco-friendly vehicles, such as hybrid cars.

[0003] Examples of secondary batteries include lithium-ion batteries, nickel-cadmium batteries, and nickel-hydrogen batteries; among these, active research and development is being conducted on lithium-ion batteries due to their high operating voltage and energy density per unit weight, as well as their advantages in charging speed and weight reduction.

[0004] A lithium secondary battery may include an electrode assembly comprising a positive electrode, a negative electrode, and a separator, and an electrolyte impregnating the electrode assembly. The lithium secondary battery may further include an outer casing, for example, in the form of a pouch, that accommodates the electrode assembly and the electrolyte.

[0005] When pouch-type lithium secondary batteries are exposed to harsh environments, gas is continuously generated inside the battery, which increases the pressure inside the pouch.

[0006] If the pressure rises above the pouch's tolerance threshold, the seal may release at the most vulnerable point, leading to ventilation (hereinafter referred to as "vent"). In particular, since vents within the pouch occur randomly, it is difficult to predict the location of occurrence. Therefore, various studies are being conducted to predict and control vents.

[0007] Korean Registered Patent Publication No. 10-1789804 discloses a pouch for a secondary battery that enables directional venting and a pouch-type secondary battery including the same. Although a lamination film is welded to the sealing portion of the pouch battery to induce directional venting of gas generated within the pouch, there are some limitations in providing sufficient venting induction effect and the resulting battery cell stability. Prior art literature

[0008] Korean Registered Patent Publication No. 10-1789804 The problem to be solved

[0009] One objective of the present invention is to provide a vent mechanism for a pouch-type secondary battery capable of preventing, controlling, and inducing venting.

[0010] One objective of the present invention is to provide a battery module capable of preventing, controlling, and inducing vents. means of solving the problem

[0011] A vent mechanism for a pouch-type secondary battery according to exemplary embodiments comprises a frame including a first frame and a second frame; and a connecting portion connecting the first frame and the second frame and having a slit formed therein, wherein at least one of the first frame and the second frame includes a vent guide portion formed by being recessed on a surface facing the other, and a vent control portion connected to the vent guide portion may be formed as a space formed between the first frame and the second frame.

[0012] In some embodiments, the connecting portion extends from the rear surface of the first frame and is connected to the rear surface of the second frame, the first frame includes a first frame opposing surface facing the second frame and a first vent guiding surface formed by being recessed from the first frame opposing surface, the second frame includes a second frame opposing surface facing the first frame and a second vent guiding surface formed by being recessed from the second frame opposing surface, and the vent guiding portion may be formed between the first frame guiding surface and the second frame guiding surface.

[0013] In some embodiments, the slit portion is formed to extend along the space between the first frame and the second frame, and the vent guide portion may be adjacent to one end of the slit and open to the outside of the frame.

[0014] In some embodiments, the vent guide may include a venting hole.

[0015] In some embodiments, the vent guide may include a venting groove.

[0016] In some embodiments, the inner shape of the venting hole may include at least one of a cylinder, a semi-cylinder, a funnel, and a polygonal prism.

[0017] In some embodiments, the average diameter of the cylindrical, semi-cylindrical, and funnel-shaped parts may be 1 to 500Φ.

[0018] In some embodiments, a plug fitted into the venting guide may be further provided.

[0019] In some embodiments, the plug may comprise a material that is more susceptible to physical deformation than the material of the first frame and the second frame.

[0020] In some embodiments, the slit portion may have a sub-venting hole having the same shape as the vent guide portion formed at a position corresponding to the vent guide portion.

[0021] In some embodiments, the gap between the first frame and the second frame may be 0.1 to 10 mm.

[0022] A battery module according to exemplary embodiments comprises: a plurality of battery cells each comprising an electrode lead and arranged in a stacked manner; and a busbar assembly coupled to the end from which the electrode leads of the plurality of battery cells are drawn out to connect the plurality of battery cells to each other, wherein the busbar assembly comprises: a main frame including a slit portion through which the electrode leads of the plurality of battery cells are drawn out; a busbar mounted on the outer surface of the main frame to electrically connect the electrode leads drawn out through the slit portion to each other; and a plurality of inner frames spaced apart from each other on the inner surface of the main frame to guide the electrode leads to the slit portion, wherein at least one of the plurality of inner frames includes a vent guide portion formed by being recessed on the surface facing an adjacent frame, and a vent control portion connected to the vent guide portion may be formed in the space formed between the at least one frame and the adjacent frame.

[0023] In some embodiments, at least one of the plurality of inner frames includes a first inner frame facing face facing the adjacent frame and a first inner vent guiding face formed by being recessed from the first inner frame facing face, and the adjacent frame includes a second inner frame facing face facing the at least one frame and a second inner vent guiding face formed by being recessed from the second inner frame facing face, and the vent guiding portion may be formed between the first inner vent guiding face and the second inner vent guiding face.

[0024] In some embodiments, the vent guide may be adjacent to one end of the slit portion and open to the outside of at least one of the plurality of inner frames.

[0025] In some embodiments, the inner shape of the vent guide may include at least one of a cylinder, a semi-cylinder, a funnel, and a polygonal prism.

[0026] In some embodiments, the battery module may further comprise a plug fitted into the venting guide.

[0027] In some embodiments, the stopper may comprise a material that is more susceptible to physical deformation than the plurality of inner frames.

[0028] In some embodiments, the spacing between each of the multiple inner frames may be 0.1 to 10 mm.

[0029] In some embodiments, the slit portion may have a sub-venting hole having the same shape as the vent guide portion formed at a position corresponding to the vent guide portion.

[0030] In some embodiments, at least one of the plurality of battery cells comprises an electrode assembly and a pouch containing the electrode assembly, the pouch comprises a sealing portion formed on the outer edge of the electrode assembly, and at least a portion of the electrode lead and the sealing portion may be located in the vent control portion.

[0031] In some embodiments, a portion of the sealing portion may contact at least a portion of the first inner frame opposing surface and the second inner frame opposing surface in the vent control portion.

[0032] In some embodiments, the sealing portion includes a side sealing portion that seals the end where the electrode lead is drawn out, and a main sealing portion that seals one side where the electrode lead is not drawn out, and a folding portion formed by folding the pouch is formed at the edge of the main sealing portion, and the area where the side sealing portion contacts the first inner frame opposing surface and the second inner frame opposing surface is 200 to 20,000 mm 2 It could be. Effects of the invention

[0033] The vent mechanism for a pouch-type secondary battery according to the embodiments of the present invention can delay venting caused by gas generated inside the pouch, and even if venting occurs, it can guide the gas in a certain direction to exhaust it, thereby preventing rupture or explosion of the battery cell in advance.

[0034] In the vent control unit of the vent mechanism for a pouch-type secondary battery according to embodiments of the present invention, pouch expansion can be prevented, thereby preventing or delaying venting.

[0035] The vent mechanism for a pouch-type secondary battery according to the embodiments of the present invention can guide the direction of gas to the vent induction part, so the point of vent occurrence can be predicted and the time of vent occurrence can also be predicted.

[0036] A battery module including a vent mechanism for a pouch-type secondary battery according to embodiments of the present invention can control the vent by enabling it to withstand pressure rising above an appropriate level inside the battery pouch, thereby improving pressure resistance characteristics, ensuring the stability of the battery cell, and preventing degradation of the battery cell performance.

[0037] A battery module including a vent mechanism for a pouch-type secondary battery according to embodiments of the present invention can predict the location and timing of vent occurrence, thereby improving the stability of the battery module. In addition, since gas generated inside the pouch can be guided in a certain direction for exhaust, a separate additional device (e.g., an exhaust unit) is not required, which can reduce manufacturing costs. Brief explanation of the drawing

[0038] FIG. 1 is a schematic perspective view showing a vent mechanism for a pouch-type secondary battery according to exemplary embodiments. FIGS. 2(a) to 2(d) show various examples of a vent guide (venting hole) according to exemplary embodiments. FIGS. 3(a) and FIGS. 3(b) respectively show schematic venting grooves and venting holes according to exemplary embodiments. FIG. 4 shows a venting hole equipped with a schematic plug according to an exemplary embodiment. FIGS. 5(a) and FIGS. 5(b) illustrate examples in which a sub-venting hole is formed in a slit portion according to exemplary embodiments. FIG. 6 is a schematic plan view of a battery cell according to exemplary embodiments. FIG. 7 is a schematic perspective view showing a battery cell unit according to an exemplary embodiment. FIG. 8 schematically illustrates the principle of a battery cell unit according to exemplary embodiments. FIG. 9 is a schematic perspective view showing a battery module according to exemplary embodiments. FIGS. 10 and FIGS. 11 are schematic cross-sectional views showing a battery module according to embodiments. Specific details for implementing the invention

[0039] A vent mechanism for a pouch-type secondary battery and a battery module including the same according to an embodiment of the present invention can prevent or delay venting generated in a battery cell. In addition, when venting occurs, the vent can be guided in a certain direction to exhaust gas generated in the pouch to the outside.

[0040] Embodiments of the present invention will be described in more detail below with reference to the drawings. However, the following drawings attached to this specification are intended to illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the aforementioned description; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0041] As used herein, the term "frame" refers to a part of a vent mechanism used to control the direction of gas generated from a battery cell in combination with the battery cell. "First frame" and "second frame" do not limit the position or order and are merely for distinguishing objects from one another.

[0042] In the vent mechanism (100) for a pouch-type secondary battery shown in FIG. 1, “L” represents the length direction from left to right or right to left of the first frame and the second frame, “H” represents the height direction from the upper side to the lower side or from the lower side to the upper side, “D” represents the thickness direction from the front to the rear or from the rear to the front, and “h” represents the gap between the first frame and the second frame.

[0043] In addition, the distance between the first frame and the second frame in FIG. 1 may be sufficiently close so that when a battery cell is inserted between the first frame and the second frame, a part of the battery cell, for example, a part of the cell’s pouch, can come into contact with the first frame and the second frame.

[0044] Referring to FIG. 1, a vent mechanism (100) for a pouch-type secondary battery according to an exemplary embodiment may include a first frame (110), a second frame (120) facing each other, and a connecting portion (150) for connecting the first frame (110) and the second frame (120). The connecting portion (150) may have a slit portion (151) formed by extending along the space between the first frame (110) and the second frame (120). In FIG. 1, the connecting portion (150) and the slit portion (151) are shown as dotted lines considering the distance between the first frame (110) and the second frame (120).

[0045] “Frame (110, 120)” may include at least one of the first frame (110) and the second frame (120). In other words, “Frame (110, 120)” may mean at least one of the first frame (110) and the second frame (120).

[0046] Additionally, the first frame (110) may include a first frame body (111), and the second frame (120) may include a second frame body (121).

[0047] Additionally, one side of the first frame (110) and the second frame (120) may face each other. The first frame (110) may include a first frame opposing surface (112) facing the second frame (120), and the second frame (120) may include a second frame opposing surface (122) facing the first frame (110).

[0048] Additionally, the first frame (110) and the second frame (120) can be connected and fixed to each other by a connecting part (150). For example, the connecting part (150) may be structured to extend from the rear of the first frame (110) and connect to the rear of the second frame (120).

[0049] Additionally, the connecting portion (150) may include, for example, a slit portion (151). For example, the slit portion (151) may be formed along the space between the first frame (110) and the second frame (120) so that when a battery cell is inserted into the vent mechanism (100) for a pouch-type secondary battery, the electrode lead of the battery cell is inserted in the thickness direction of the first frame (110) and the second frame (120). The size or length of the formed slit portion (151) may be appropriately adjusted within a range through which the electrode lead of the battery cell can pass.

[0050] Additionally, at least one of the first frame (110) and the second frame (120) may include a vent guide (130) formed by being recessed on the surface facing the other.

[0051] Additionally, a vent control unit (140) connected to the vent induction unit (130) may be formed as a space formed between the first frame (110) and the second frame (120).

[0052] For example, the first frame (110) includes a first frame facing surface (112) facing the second frame (120) and a first vent guide surface (131) formed by being recessed from the first frame facing surface (112), and the second frame (120) includes a second frame facing surface (122) facing the first frame (110) and a second vent guide surface (132) formed by being recessed from the second frame facing surface (122), and the vent guide portion (130) may be formed between the first vent guide surface (131) and the second vent guide surface (132).

[0053] For example, a first vent guide surface (131) formed by being sunken in the first frame opposing surface (112) and a second vent guide surface (132) formed by being sunken in the second frame opposing surface (122) may face each other to form a venting groove or venting hole as a vent guide portion (130).

[0054] Additionally, the position or shape of the vent guide (130) formed on the frame (110, 120) can be appropriately adjusted.

[0055] For example, as shown in FIG. 2(a), a vent guide (130) may be formed at the edge of the frame (110, 120). In other words, the vent guide (130) may be adjacent to one end of the slit portion (150) and open to the outside of the frame (110, 120).

[0056] For example, as shown in FIGS. 2(b) to 2(d), the vent guide (130) may be formed in an internal area of ​​the first frame (110) and the second frame (120).

[0057] For example, as shown in FIG. 3(a), the vent guide (130) may include a venting groove (135). For example, the venting groove (135) may include a groove formed on the front surface of the first frame (110). For example, the venting groove (135) may be recessed from the front surface of the first frame (110) but spaced apart from the rear surface of the first frame (110).

[0058] For example, as shown in FIG. 3(b), a venting hole (137) may be included. For example, the venting hole (137) may be a hole or opening formed on the front surface of the first frame (110). For example, the venting hole (137) may be a hole extending from the front surface of the first frame (110) to the rear surface of the first frame (110).

[0059] The above venting groove (135) or the above venting hole (137) can serve as a passage for gas to be exhausted to the outside when a vent occurs due to an increase in internal pressure of the pouch during operation when a battery cell is inserted between the first frame (110) and the second frame (120).

[0060] According to one embodiment, the inner shape of the venting hole (137) may include, for example, at least one of a cylinder, a semi-cylinder, a funnel, and a polygonal prism.

[0061] Referring to FIGS. 2(a) to 2(d), the inner shape of the venting hole (137) may be a cylinder, a semi-cylinder, or a funnel.

[0062] For example, as shown in FIG. 2(c), when the inner shape is a funnel, the structure may be formed in a shape inclined at a predetermined angle from the front to the rear of the frame (110, 120). For example, the angle may decrease from the front to the rear of the frame (110, 120), or conversely, the angle may increase from the rear to the front of the frame (110, 120).

[0063] In addition, although not shown in FIG. 2, the polygonal prism may be, for example, a triangular prism or an octagonal prism.

[0064] In the embodiments, unlike the vent control unit described later, the venting groove or the vent guide provided through the venting hole cannot structurally contact a part of the battery cell pouch with the frame, so a relative clearance space can be formed for the pouch to expand when gas is generated inside the pouch. Therefore, gas can be guided to the vent guide. This allows for easy guidance or control of the vent without the need for separate additional parts or devices.

[0065] According to one embodiment, when the inner shape of the venting hole is selected from a cylinder, a semi-cylinder, and a funnel, the average diameter may be 1 to 500Φ or 5 to 100Φ. When the average diameter is within the above range, it can serve as a smooth passage when gas is guided to the vent guide and exhausted.

[0066] According to one embodiment, as shown in FIG. 4, the venting guide (130) may further be provided with a plug (115, 125).

[0067] If a plug is additionally provided in the venting guide, a part of the battery cell pouch, for example, the pouch sealing part, may come into contact with the first plug and / or the second plug even in the venting guide. In this case, the plug may comprise a flexible material that is susceptible to physical deformation compared to the material forming the first frame or the second frame.

[0068] For example, if pressure exceeding a certain level is applied to the stopper in the height, thickness, or length direction of the frame, the stopper may be separated from the frame.

[0069] For example, if heat exceeding a certain level is applied to the stopper in the height, thickness, or length direction of the frame, the stopper may melt.

[0070] In some embodiments, the stopper may include a low-melting point material. For example, it may include any one of the metals tin (Sn), zinc (Zn), lead (Pb), bismuth (Bi), and indium (In), or tin (Sn), zinc (Zn), lead (Pb), bismuth (Bi), and indium (In). Therefore, when heat or gas is generated in extreme situations, it can be deformed into a fluid state, so it can be deformed or discharged to the outside by internal heat or pressure, thus forming a gas exhaust passage even if gas is generated.

[0071] Referring to FIGS. 5(a) and FIGS. 5(b), the slit portion (151) may have a sub-venting hole (153) having the same shape as the vent guide portion (130) formed at a position corresponding to the vent guide portion (130). Thus, it can serve as an additional passage so that gas can be finally discharged to the outside when a vent occurs.

[0072] As illustrated in FIG. 5(a), when the vent guide (130) is formed inside the frame (110, 120), the sub-venting hole (153) may also be formed inside the slit portion (151). As illustrated in FIG. 5(b), when the vent guide (130) is formed at one end of the frame (110, 120), the sub-venting hole (153) may also be formed at one end of the slit portion (151) and may have a structure that is open to the outside of the connecting portion (150). That is, when the sub-venting hole (153) is formed with the same shape corresponding to the position corresponding to the vent guide (130), it can provide a structure that is more advantageous for vent control.

[0073] Meanwhile, as illustrated in FIG. 1, the vent control unit (140) may be formed as a space formed between the first frame (110) and the second frame (120) and connected to the vent guide unit (130). In other words, it may be formed between the first frame (110) and the second frame (120) along the longitudinal direction (L) of the frames (110, 120) and connected to the vent guide unit (130). For example, when the electrode lead of a battery cell is inserted into the slit (151) of the vent mechanism (100) for a pouch-type secondary battery, the sealing portion of the battery cell pouch may come into contact with one side of the frames (110, 120) at the vent control unit (140). For better understanding, the gap between the frames in FIG. 1 is depicted as being relatively farther than the actual gap, but it may be a sufficiently close distance so that when a battery cell is inserted between the frames, a part of the battery cell can come into contact with one side of the frame. Therefore, if gas is generated inside the pouch, it is difficult to form a space for the pouch to expand, which constrains the pouch's expansion and can prevent or delay the occurrence of venting.

[0074] According to some embodiments, the gap between the first frame and the second frame may be 0.1 to 10 mm. Referring to FIG. 1, the gap between the first frame (110) and the second frame (120) is h, and h may preferably be 2 to 5 mm. When the gap between the frames is within the above range, the battery cell can be inserted and fixed in the vent mechanism, and the expansion of the pouch during battery cell operation can be effectively suppressed.

[0075] According to some embodiments, the length of each of the first frame and the second frame may be 10 to 500 mm in the L direction, the height may be 1 to 50 mm in the H direction, and the thickness may be 1 to 50 mm in the D direction. Preferably, the length may be 5 to 300 mm, the height may be 5 to 30 mm, and the thickness may be 5 to 30 mm. The size or shape of the vent mechanism can be varied within a range where the battery cell can be applied to the vent mechanism without difficulty, and the vent direction can be controlled by applying the battery cell within the vent mechanism.

[0076] According to one embodiment, the frames may include a material with high rigidity and elasticity to withstand external physical and chemical forces. Additionally, the connecting part may also be made of the same material as the frames. Furthermore, it is important to withstand extreme conditions by having higher rigidity or elasticity than the material included in the stopper. For example, the frames may include plastic, metal, ceramic, etc. Specifically, the plastic may be general-purpose plastic, engineering plastic, etc., the metal may be aluminum, copper, iron, stainless steel, etc., and the polymer may be rubber, polyurethane foam, etc.

[0077] According to some embodiments, the first frame, the second frame, and the connecting part may be formed integrally.

[0078] A pouch-type battery cell unit according to an exemplary embodiment may be implemented by inserting a battery cell into the vent mechanism for a pouch-type secondary battery described above. The specific details of the vent mechanism for a pouch-type secondary battery may be applied in the same manner as described above.

[0079] Referring to FIG. 6, the battery cell (200) may include an electrode assembly (210) having an electrode lead (220) formed at one end and a pouch (230) that accommodates the electrode assembly (210).

[0080] The “electrode lead (220)” may include at least one of the first electrode lead (221) and the second electrode lead (222). In other words, the “electrode lead (220)” may mean at least one of the first electrode lead (221) and the second electrode lead (222).

[0081] Additionally, the pouch (230) may have a sealing portion (240) formed on the outer edge of the electrode assembly (210).

[0082] Additionally, the sealing portion (240) may include a side sealing portion (241) that seals the end where the electrode lead (220) is drawn out, and a main sealing portion (243) that seals the side where the electrode lead (220) is not drawn out. Additionally, a folding portion (245) formed by folding the pouch (230) may be formed at the edge of the main sealing portion (243).

[0083] In this specification, the side sealing portion refers to a sealing portion located in the direction in which the electrode lead is drawn out among the sealing portions formed on the outer edge of the electrode assembly. The main sealing portion refers to a sealing portion that extends from the side sealing portion and is located in the direction in which the electrode lead is not drawn out. The folding portion refers to a structure in which a pouch extends from the edge of the main sealing portion and is folded.

[0084] For example, the folding portion can prevent the formation of unnecessary space between adjacent battery cells when assembling a battery module. Since the folding portion is formed to be smaller than the thickness of the electrode assembly, it does not protrude, allowing adjacent secondary batteries to be in close contact without creating space between them, thereby increasing volumetric efficiency during battery module assembly.

[0085] FIG. 7 is a perspective view showing a battery cell unit according to an exemplary embodiment. Referring to FIG. 7, a battery cell (200) can be inserted into a venting mechanism (100) of a pouch-type secondary battery. For example, the electrode lead (220) of the battery cell (200) can be inserted from the front to the rear of the frame (110, 120) into a slit portion (151) of the venting mechanism (100) of the pouch-type secondary battery. In this case, a portion of the inserted electrode lead (220) and the battery cell (200) sealing portion (240) can be located in a vent control portion (140). For example, a side sealing portion (241) of the inserted pouch sealing portion (240) can be located in the vent control portion (140) and come into contact with the first frame opposing surface (112) and the second frame opposing surface (122).

[0086] When the pouch sealing portion (240) comes into contact with the frame opposing surface (112, 122), the expansion of the pouch can be restrained by the frame even if gas is generated inside the pouch. Therefore, the force attempting to release the seal of the pouch sealing portion (240) due to gas expansion can be suppressed, thereby suppressing or delaying the occurrence of vent.

[0087] FIG. 8 schematically illustrates the venting principle of a battery cell unit according to an exemplary embodiment. Point (A) of the vent control unit (140) shows the venting being controlled, and point (B) of the vent induction unit (130) shows the venting being induced.

[0088] One point (A) of the vent control unit (140) is in direct contact with the first frame (110) and the second frame (120) when the pouch (230) of the battery cell (200) expands, thereby suppressing the expansion of the sealing portion of the pouch (230) and thus delaying or suppressing the occurrence of a vent. In other words, control of the vent is possible.

[0089] On the other hand, point (B) of the vent induction section (130) indicates the appearance of inducing venting. Since the expansion of the sealing section of the pouch (230) cannot be suppressed by the vent induction section (130) at (B), when gas is generated inside the pouch (230), the gas moves to (B), where a relatively space is secured, allowing the pouch to expand. Furthermore, if the internal gas pressure exceeding the adhesive force of the sealing section occurs, the sealing section opens, allowing the gas to be exhausted to the outside. In other words, since the vent induction section (130) can exhaust the gas generated inside the pouch (230), the rupture or explosion of the battery cell can be prevented in advance. Additionally, since the direction of gas exhaust can be controlled by the vent induction section (130), the point where the vent occurs can be easily predicted.

[0090] According to the venting principle of a battery cell unit according to one embodiment, venting can be controlled by enabling the secondary battery to withstand pressure rising above an appropriate level, thereby improving pressure resistance characteristics, ensuring battery stability, and preventing battery performance degradation.

[0091] A battery module according to an exemplary embodiment may have the venting principle of the battery cell unit applied.

[0092] According to one embodiment, the battery module may include a plurality of battery cells and a busbar assembly.

[0093] Referring to FIG. 9, the battery module (400) can be stacked such that one side of a plurality of battery cells (200) is in contact with one another. The stacked plurality of battery cells (200) can form, for example, a battery stack, and the plurality of battery cells (200) can be electrically connected to each other by a busbar assembly (300).

[0094] Each of the plurality of battery cells (200) may be formed in a pouch shape in which an electrode assembly (210) is wrapped by a pouch (230), as shown in FIG. 6. For example, it may include an electrode assembly (210) having an electrode lead (220) formed at one end and a pouch (230) that accommodates the electrode assembly (210).

[0095] Additionally, the pouch (230) may have a sealing portion (240) formed on the outer edge of the electrode assembly (230). Specific details regarding the sealing portion are the same as those described above.

[0096] As illustrated in FIG. 9, the busbar assembly (300) may include a first busbar assembly disposed at one end of a plurality of stacked battery cells (200), and a second busbar assembly disposed at the other end of the plurality of stacked battery cells (200). That is, the first busbar assembly and the second busbar assembly may be disposed spaced apart from each other on one side and the other side of the plurality of battery cells (200), respectively.

[0097] A busbar assembly (300) according to an exemplary embodiment may include a main frame (320), a busbar (340), and an inner frame (360).

[0098] A busbar assembly (300) can be coupled to one end and the other end of a plurality of stacked battery cells (200), and electrode leads (220) drawn out from both ends of each battery cell (200) are inserted into a slit portion (151) formed in the main frame (320) of the busbar assembly (300), drawn out through the main frame (320), and can be electrically connected to each other by a busbar (340).

[0099] In this specification, the outer surface of the main frame (320) refers to the side opposite to where the battery cell (200) is placed, and the inner surface refers to the side on which the battery cell (200) is placed.

[0100] According to one embodiment, the main frame (320) may have a plurality of slit portions (151) formed therein to accommodate electrode leads (220) of a battery cell (200). Electrode leads (220) drawn from each battery cell (200) may be inserted and drawn out through each formed slit portion (151).

[0101] According to one embodiment, a bus bar (340) capable of electrically connecting an electrode lead (220) drawn out through the slit portion (151) may be mounted on the outer surface of the main frame (320).

[0102] According to one embodiment, the inner surface of the main frame (320) may include a plurality of inner frames (360) spaced apart from each other and guiding the electrode lead (220) to the slit portion (151). The spacing between the plurality of inner frames (360) may be 0.1 to 10 mm. In other words, the spacing between at least one frame among the plurality of inner frames and an adjacent frame may be 0.1 to 10 mm.

[0103] FIG. 9 shows a perspective view of a battery module according to exemplary embodiments. FIG. 10 and FIG. 11 show cross-sectional views of a battery module according to exemplary embodiments.

[0104] FIG. 10 is a cross-sectional view of the battery module (400) cut along the imaginary line B-B' in FIG. 9 in the Y-axis direction. At the location corresponding to B-B' in the battery module (400), the inner frame (360) may include a venting guide (130). FIG. 11 is a cross-sectional view of the battery module cut along the imaginary line A-A' in FIG. 9 in the Y-axis direction. At the location corresponding to A-A' in the battery module (400), the inner frame (360) may include a vent control unit (a space formed between the inner frames (360)).

[0105] Referring to FIGS. 9 and 10, a plurality of inner frames (360) may be arranged at predetermined intervals along the direction (X-axis direction) in which a plurality of battery cells (200) are stacked. A battery cell (200) may be positioned between the arranged inner frames (360). In other words, the inner frames (360) and the battery cells (200) may be arranged alternately. Additionally, at least one of the plurality of inner frames (360) may have a vent guide (130) formed by being recessed on the surface facing an adjacent frame.

[0106] As illustrated in FIG. 10, at least one of the plurality of inner frames (360) includes a first inner frame facing surface (361) facing the adjacent frame and a first inner vent guiding surface (362) formed by being recessed from the first inner frame facing surface (361), and the adjacent frame includes a second inner frame facing surface (363) facing the at least one frame and a second inner vent guiding surface (364) formed by being recessed from the second inner frame facing surface (363), and the vent guiding portion (130) may be formed between the first inner vent guiding surface (362) and the second inner vent guiding surface (364).

[0107] In some embodiments, a vent guide may be formed in which all of the plurality of inner frames are recessed on the surface facing the adjacent frame.

[0108] According to some embodiments, the vent guide may be adjacent to one end of the slit portion and open to the outside of at least one of the plurality of inner frames.

[0109] According to some embodiments, the inner shape of the venting guide may be, for example, a cylinder, a semi-cylinder, a funnel, or a polygonal prism.

[0110] In other words, as long as the vents generated from the battery cell are within a controllable range, the number, shape, size, and location of the vent guides formed in the internal frame can be appropriately adjusted.

[0111] Furthermore, unlike the vent control unit, the vent induction unit cannot structurally contact the sealing portion of the battery cell pouch with the frame; thus, a relative clearance can be formed for the pouch to expand when gas is generated within it. Consequently, gas can be guided to the vent induction unit. This allows for easy venting or control without the need for separate additional parts or devices.

[0112] According to one embodiment, when the inner shape of the vent hole is selected from a cylinder, a semi-cylinder, and a funnel, the average diameter may be 1 to 500Φ or 5 to 100Φ. When the average diameter is within the above range, it can serve as a smooth passage when gas is guided to the vent guide and exhausted.

[0113] According to one embodiment, the venting guide may further comprise a plug. The plug may comprise a flexible material that is susceptible to physical deformation compared to the material forming the first frame or the second frame.

[0114] In addition, although not shown in FIGS. 9 and 10, the slit portion may have a sub-venting hole formed with the same shape as the vent guide portion at a position corresponding to the vent guide portion, so that it may serve as an additional passage to allow gas to be finally discharged to the outside when a vent occurs. Thus, the stability of the battery cell can be ensured by effectively controlling the vent. This can prevent chain explosions at the module level, thereby ensuring the stability of the battery module.

[0115] The specific details of the above-mentioned vent induction unit and vent control unit can be applied in the same way as the details described above regarding the vent mechanism for pouch-type secondary batteries and the venting principle of battery cell units.

[0116] When the electrode lead of a battery cell is inserted into the slit portion of a bus assembly according to one embodiment, at least a portion of the electrode lead of the battery cell and the sealing portion may be located in the vent control portion. For example, the sealing portion may be in direct contact with at least a portion of the inner frame facing surface in the vent control portion. For example, the side sealing portion among the sealing portions may be in direct contact with at least a portion of the inner frame facing surface.

[0117] Referring to FIG. 11, the side sealing portion (241) of the battery cell (200) may come into contact with at least a portion of the first and second inner frame opposing surfaces (361, 363) in the vent control portion.

[0118] For example, the area where the side sealing portion (241) contacts the first and second inner frame opposing surfaces (361, 363) is 200 to 20,000 mm 2 It may be. Preferably 800 to 20,000 mm 2 It may be. For example, the area where the side sealing portion (241) contacts the first inner frame opposing surface (361) is 50 to 5,000 mm 2 It may be, and the contact area with the second inner frame opposing surface (363) is 50 to 5,000 mm 2It may be possible. For example, contact may be made at a first busbar assembly placed at one end of the battery module (400) and at a second busbar assembly placed at the other end, respectively. An optimized vent delay or suppression effect may be provided within the above range.

[0119] On the other hand, referring to FIG. 10, the vent guide (130) formed within the plurality of inner frames (360) does not come into contact with the inner frame opposing surfaces (361, 363) and the side sealing portion (241), so it can provide a space for the pouch to expand when gas is generated inside the battery cell (200) pouch. Furthermore, when gas internal pressure exceeding the adhesive force of the pouch sealing portion (240) occurs, the sealing portion (240) can be opened so that the gas can be exhausted to the outside.

[0120] According to one embodiment, the battery cell may preferably be a lithium secondary battery. The battery cell may include a pouch and an electrode assembly as described above. The electrode assembly may include electrodes that are repeatedly stacked and a separator disposed between the electrodes. Additionally, each electrode may include an active material layer formed on an electrode current collector.

[0121] The electrodes may include a positive electrode and a negative electrode. The electrode current collector may include a positive current collector included in the positive electrode and a negative current collector included in the negative electrode. The active material layer may include a positive active material layer included in the positive electrode and a negative active material layer included in the negative electrode.

[0122] The positive electrode may include a positive current collector and a positive active material layer formed by coating a positive active material on the positive current collector. The positive active material may include a compound capable of reversibly intercalating and deintercalating lithium ions.

[0123] In some embodiments, the positive electrode active material may comprise lithium-transition metal composite oxide particles. Examples of lithium-transition metal composite oxides included in the lithium-transition metal composite oxide particles include lithium-manganese-based oxides, lithium-cobalt-based oxides, lithium-nickel-based oxides, lithium-manganese-cobalt-based oxides, etc. Additionally, in some exemplary embodiments, the lithium-transition metal composite oxide particles may comprise nickel (Ni) and may further comprise at least one of cobalt (Co) or manganese (Mn).

[0124] For example, the lithium-transition metal composite oxide particles can be represented by the following chemical formula 1.

[0125] [Chemical Formula 1]

[0126] Li x Ni 1-y M y O 2-z X z

[0127] In Chemical Formula 1, 0.9≤x≤1.1, y is 0≤y≤0.7, and z is -0.1≤z≤0.1. M may represent one or more elements selected from Na, Mg, Ca, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Fe, Cu, Ag, Zn, B, Al, Ga, C, Si, Sn, or Zr, and X may represent an element selected from O, F, S, and P.

[0128] In some embodiments, the molar ratio (1-y) of nickel in Formula 1 may be in the range of 0.8 to 0.95. In this case, the output and capacity can be increased through a high-nickel (High-Ni) cathode composition. The higher the nickel content in the cathode active material, the greater the generation of gas due to side reactions between the cathode active material and the electrolyte.

[0129] In addition, the lithium-transition metal composite oxide particles can be represented by the following chemical formula 2, and the lithium-transition metal composite oxide particles represented by chemical formula 2 may have an olivine structure.

[0130] [Chemical Formula 2]

[0131] LiMPO4

[0132] In Chemical Formula 2, M is at least one element among Fe, Mn, Ni, Co, and V.

[0133] The positive current collector may include a metal material that is non-reactive within the charge / discharge voltage range of the lithium secondary battery and facilitates the coating and adhesion of the electrode active material. For example, the positive current collector may include stainless steel, nickel, aluminum, titanium, copper, zinc, or an alloy thereof, and preferably may include aluminum or an aluminum alloy.

[0134] For example, the above-mentioned positive active material can be mixed and stirred with a binder, a conductive material and / or a dispersant, etc., in a solvent to prepare a slurry. After coating the slurry onto a positive current collector, a positive electrode including a layer of positive active material can be prepared by compressing and drying.

[0135] The above binder may include, for example, organic binders such as vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidenefluoride (PVDF), polyacrylonitrile, and polymethylmethacrylate, or water-based binders such as styrene-butadiene rubber (SBR), and may be used together with a thickener such as carboxymethyl cellulose (CMC).

[0136] For example, a PVDF-based binder can be used as the anode binder. In this case, the amount of binder required to form the anode active material layer can be reduced, and the amount of the anode active material can be relatively increased, thereby improving the output and capacity of the secondary battery.

[0137] The above conductive material may be included to promote electron transfer between active material particles. For example, the conductive material may include carbon-based conductive materials such as graphite, carbon black, graphene, carbon nanotubes, etc.; metal-based conductive materials such as tin, tin oxide, titanium oxide; and perovskite materials such as LaSrCoO3, LaSrMnO3, etc.

[0138] It may include a negative electrode current collector and a negative electrode active material layer formed by coating a negative electrode active material onto the negative electrode current collector.

[0139] The above-mentioned negative electrode active material may be an active material known in the art capable of absorbing and extracting lithium ions. For example, carbon-based materials such as crystalline carbon, amorphous carbon, carbon composites, and carbon fibers; lithium alloys; and silicon (Si)-based active materials may be used. Examples of the above-mentioned amorphous carbon include hard carbon, coke, mesocarbon microbeads (MCMB), and mesophase pitch-based carbon fibers (MPCF).

[0140] Examples of the above-mentioned crystalline carbon include graphite-based carbons such as natural graphite, artificial graphite, graphitized coke, graphitized MCMB, and graphitized MPCF. Examples of elements included in the above-mentioned lithium alloy include aluminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium, or indium.

[0141] In one embodiment, to realize a high-capacity lithium secondary battery, the negative electrode active material may include a silicon-based active material. The silicon-based active material is SiO₂ X (0 <x<2) 또는 리튬 화합물이 포함된 SiOx(0<x<2)를 포함할 수 있다. 리튬 화합물이 포함된 SiOx는 리튬 실리케이트를 포함하는 SiOx일 수 있다. 리튬 실리케이트는 SiOx(0<x<2) 입자의 적어도 일부에 존재할 수 있으며, 예를 들면, SiOx(0<x<2) 입자의 내부 및 / 또는 표면에 존재할 수 있다. 일 실시예에 있어서, 리튬 실리케이트는 Li2SiO3, Li2Si2O5, Li4SiO4, Li4Si3O8등을 포함할 수 있다.

[0142] The above silicon-based active material may include, for example, a silicon-carbon composite compound such as silicon carbide (SiC).

[0143] The cathode current collector may comprise stainless steel, copper, nickel, aluminum, titanium, or an alloy thereof. Preferably, the cathode current collector may comprise copper or a copper alloy.

[0144] For example, the above-described binder, conductive material, thickener, etc. can be mixed and stirred together in the above-described cathode active material and solvent to form a slurry. After coating the slurry onto at least one surface of a cathode current collector, a cathode comprising a cathode active material layer can be manufactured by compression and drying.

[0145] As the binder and conductive material, materials substantially identical or similar to the materials described above used in the positive active material layer may be used. In some embodiments, the binder for forming the negative electrode may include, for example, a water-based binder such as styrene-butadiene rubber (SBR) for compatibility with the carbon-based active material, and may be used together with a thickener such as carboxymethyl cellulose (CMC).

[0146] A separator may be interposed between the anode and the cathode. The separator may comprise a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer. The separator may also comprise a nonwoven fabric formed of high-melting-point glass fibers, polyethylene terephthalate fibers, etc.

[0147] According to exemplary embodiments, an electrode cell is defined by an anode, a cathode, and a separator, and a plurality of electrode cells may be stacked to define an electrode assembly. A battery cell (secondary battery) may be defined by housing the electrode assembly together with an electrolyte in a pouch. According to exemplary embodiments, a non-aqueous electrolyte may be used as the electrolyte.

[0148] The non-aqueous electrolyte comprises a lithium salt as an electrolyte and an organic solvent, and the lithium salt is, for example, Li + X - It is expressed as and the anion (X) of the above lithium salt - As F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C -, (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - Examples of the back can be given.

[0149] Examples of the above organic solvents may include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), methylpropyl carbonate, dipropyl carbonate, dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, vinylene carbonate, sulfolane, gamma-butyrolactone, propylene sulfite, and tetrahydrofuran. These may be used individually or in combination of two or more.

[0150] The electrode current collector may include a notching portion. The notching portion (not shown) may be provided, for example, as an electrode tab. The notching portion may include an anode notching portion protruding from the anode current collector and a cathode notching portion protruding from the cathode current collector.

[0151] The electrode lead is electrically connected to the notching portion and can be exposed to the outside of the pouch. The electrode lead can be provided as an external connection lead for power application to the secondary battery. Additionally, the electrode lead can be subdivided into a positive lead and a negative lead.

[0152] In some embodiments, the positive lead and the negative lead may be disposed on opposite sides of the secondary battery. In some embodiments, the positive lead and the negative lead may be fused together on one side of the pouch. Accordingly, when the electrode leads are disposed on both sides of the secondary battery, the vent mechanism for the pouch-type secondary battery may also be disposed on both sides of the secondary battery. Additionally, when the electrode leads are disposed on one side of the secondary battery, the vent mechanism for the pouch-type secondary battery may also be disposed on one side of the secondary battery. That is, the position of the vent mechanism can be appropriately modified and applied according to the structure of the pouch-type secondary battery.

[0153] The present invention will be described in detail above through representative embodiments.

[0154] Although it has been stated, those skilled in the art to which the present invention pertains will understand that various modifications are possible to the above-described embodiments within the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof. Explanation of the symbols

[0155] 100: Vent mechanism for pouch-type secondary battery 110: First frame 111: First frame body 112: First frame opposite surface 115: First plug 120: Second frame 121: Second frame body 122: Second frame opposite surface 125: Second plug 130: Vent guide 131: 1st vent guide surface 132: 2nd vent guide surface 135: Venting Home 137: Venting Hole 140: Vent control unit 150: Connection unit 151: Slit section 153: Sub-venting hole 200: Battery cell 210: Electrode assembly 220: Electrode lead 221: First electrode lead 222: Second electrode lead 230: Pouch 240: Sealing section 241: Side sealing section 243: Main sealing section 245: Folding section 300: Busbar Assembly 320: Main Frame 340: Busbar 360: Internal frame 361: First inner frame opposing surface 362: First inner vent guiding surface 363: Second inner frame counter-surface 364: Second inner vent guiding surface 400: Battery module L: Length of the first and second frames H: Height of the first and second frames D: Thickness of the first and second frames h: Spacing between the first and second frames A: Venting control point B: Venting induction point

Claims

Claim 1 A vent mechanism for a pouch-type secondary battery, comprising: a frame including a first frame and a second frame each having a front and a rear surface facing each other; and a connecting portion extending from the rear surface of the first frame and connecting to the rear surface of the second frame, having a slit portion formed therein into which an electrode lead is inserted, wherein at least one of the first frame and the second frame is formed by being recessed on a surface facing the other and has a vent guide portion in communication with the slit portion, and a vent control portion connected to the vent guide portion is formed as a space formed between the first frame and the second frame. Claim 2 A vent mechanism for a pouch-type secondary battery according to claim 1, wherein the first frame includes a first frame opposing surface facing the second frame and a first vent guiding surface formed by being recessed from the first frame opposing surface, and the second frame includes a second frame opposing surface facing the first frame and a second vent guiding surface formed by being recessed from the second frame opposing surface, and the vent guiding portion is formed between the first frame guiding surface and the second frame guiding surface. Claim 3 A vent mechanism for a pouch-type secondary battery according to claim 1, wherein the slit portion is formed to extend along the space between the first frame and the second frame, and the vent guide portion is adjacent to one end of the slit portion and is open to the outside of the frame. Claim 4 A vent mechanism for a pouch-type secondary battery according to claim 1, wherein the vent induction portion includes a venting groove. Claim 5 A vent mechanism for a pouch-type secondary battery according to claim 1, wherein the vent induction portion includes a venting hole. Claim 6 A vent mechanism for a pouch-type secondary battery according to claim 5, wherein the inner shape of the venting hole comprises at least one of a cylinder, a semi-cylinder, a funnel, and a polygonal prism. Claim 7 A vent mechanism for a pouch-type secondary battery according to claim 6, wherein the average diameter of the cylinder, semi-cylinder, and funnel shapes is 1 to 500Φ. Claim 8 A vent mechanism for a pouch-type secondary battery according to claim 5, further comprising a plug fitted into the vent guide portion. Claim 9 A vent mechanism for a pouch-type secondary battery according to claim 8, wherein the plug comprises a material more susceptible to physical deformation than the material of the first frame and the second frame. Claim 10 A vent mechanism for a pouch-type secondary battery according to claim 1, wherein the slit portion has a sub-venting hole having the same shape as the vent guide portion formed at a position corresponding to the vent guide portion. Claim 11 A vent mechanism for a pouch-type secondary battery according to claim 1, wherein the distance between the first frame and the second frame is 0.1 to 10 mm. Claim 12 A battery module comprising: a plurality of battery cells each including an electrode lead and arranged in a stacked manner; and a busbar assembly coupled to the end from which the electrode leads of the plurality of battery cells are drawn out to connect the plurality of battery cells to each other, wherein the busbar assembly comprises: a main frame including a slit portion through which the electrode leads of the plurality of battery cells are drawn out; a busbar mounted on the outer surface of the main frame to electrically connect the electrode leads drawn out through the slit portion to each other; and a plurality of inner frames spaced apart from each other on the inner surface of the main frame to guide the electrode leads to the slit portion, wherein at least one of the plurality of inner frames is formed by being recessed on the surface facing an adjacent frame and includes a vent guide portion communicating with the slit portion, and a vent control portion connected to the vent guide portion is formed in a space formed between the at least one frame and the adjacent frame. Claim 13 A battery module according to claim 12, wherein at least one of the plurality of inner frames includes a first inner frame facing surface facing the adjacent frame and a first inner vent guiding surface formed by being recessed from the first inner frame facing surface, and the adjacent frame includes a second inner frame facing surface facing the at least one frame and a second inner vent guiding surface formed by being recessed from the second inner frame facing surface, and the vent guiding portion is formed between the first inner vent guiding surface and the second inner vent guiding surface. Claim 14 A battery module according to claim 12, wherein the vent guide is adjacent to one end of the slit portion and is open to the outside of at least one of the plurality of internal frames. Claim 15 A battery module according to claim 12, wherein the inner shape of the vent guide comprises at least one of a cylinder, a semi-cylinder, a funnel, and a polygonal prism. Claim 16 A battery module according to claim 12, further comprising a plug fitted into the vent guide. Claim 17 A battery module according to claim 16, wherein the plug comprises a material more susceptible to physical deformation than the plurality of inner frames. Claim 18 A battery module according to claim 12, wherein the spacing between each of the plurality of inner frames is 0.1 to 10 mm. Claim 19 A battery module according to claim 12, wherein the slit portion has a sub-venting hole having the same shape as the vent guide portion formed at a position corresponding to the vent guide portion. Claim 20 A battery module according to claim 13, wherein at least one of the plurality of battery cells comprises an electrode assembly and a pouch containing the electrode assembly, the pouch comprises a sealing portion formed on the outer edge of the electrode assembly, and at least a portion of the electrode lead and the sealing portion is located in the vent control portion. Claim 21 A battery module according to claim 20, wherein at least a portion of the sealing portion contacts at least a portion of the first inner frame opposing surface and the second inner frame opposing surface in the vent control portion. Claim 22 In claim 21, the sealing portion comprises a side sealing portion that seals the end where the electrode lead is drawn out, and a main sealing portion that seals one side where the electrode lead is not drawn out, wherein a folding portion in which the pouch is folded is formed at the edge of the main sealing portion, and the area where the side sealing portion contacts the first inner frame opposing surface and the second inner frame opposing surface is 200 to 20,000 mm 2 Battery module.

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