Secondary battery

Abstract

Provided is a secondary battery comprising: a stacked electrode assembly comprising a plurality of unit cells stacked in a first direction and having electrode leads at both ends thereof in a second direction perpendicular to the first direction; a multifunctional terminal block (MTB) provided at at least one end of the stacked electrode assembly; and a laminate sheet surrounding the side surface of the stacked electrode assembly to define a cell inner space.

Description

secondary batteries

[0001] The present invention relates to a secondary battery, and more particularly, to a secondary battery capable of effectively discharging gas generated internally and preventing moisture infiltration.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0115109, filed August 31, 2023, the entire disclosure of which is incorporated herein by reference.

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are widely used as a power source for various wireless devices, including handsets, laptops, and cordless vacuum cleaners. Recently, improved energy density and economies of scale have dramatically reduced the per-unit manufacturing cost of secondary batteries. Furthermore, as the range of battery electric vehicles (BEVs) has increased to match that of fuel-powered vehicles, the primary use of secondary batteries is shifting from mobile devices to mobility.

[0004] Meanwhile, demand for large-capacity battery packs for electric vehicles and other applications is increasing. Large-capacity battery packs installed in automobiles are expected to increase capacity and enhance safety.

[0005] The technical problem to be achieved by the present invention is to provide a secondary battery that can effectively discharge gas generated internally and prevent moisture infiltration.

[0006] In order to achieve the above technical problem, the present invention provides a secondary battery including a stacked electrode assembly in which a plurality of unit cells are stacked in a first direction and have electrode leads at both ends in a second direction perpendicular to the first direction; a multifunctional terminal block (MTB) provided at at least one end of the stacked electrode assembly; and a laminate sheet wrapping a side surface of the stacked electrode assembly to define a cell internal space. The MTB may include an electrode terminal portion electrically connected to the electrode leads of the stacked electrode assembly; a check valve configured to discharge gas in the cell internal space exceeding a first pressure; and a venting disk configured to rupture and discharge gas when the pressure in the cell internal space increases to a second pressure exceeding the first pressure.

[0007] In some embodiments, the check valve may be configured to switch from a closed state to an open state when the pressure in the space inside the cell exceeds the first pressure, and to switch from an open state to a closed state after the pressure in the space inside the cell is relieved to be lower than the first pressure.

[0008] In some embodiments, the check valve may include a conduit portion communicating with the internal space of the cell and opening to the outside of the secondary battery; a valve packing provided within the conduit portion and movable toward the outside of the secondary battery by the pressure of the internal space of the cell; and an elastic body that returns the valve packing to its original position according to the pressure of the internal space of the cell.

[0009] In some embodiments, the conduit portion includes a first catch provided at an end on the inner space side of the cell; and a second catch provided on an inner circumferential surface of the conduit portion spaced apart from the first catch, the valve packing may be disposed between the first catch and the second catch, and the elastic body may be disposed between the valve packing and the second catch.

[0010] In some embodiments, the check valve may include an O-ring provided between the valve packing and the conduit portion, the valve packing including a tapered side surface having a diameter that decreases toward the cell interior space, the tapered side surface being configured to achieve the closed state by making hermetic contact with the O-ring, and the tapered side surface being configured to achieve the open state by being spaced apart from the O-ring.

[0011] In some embodiments, the check valve may further include a waterproof membrane at the end of the conduit portion.

[0012] In some embodiments, the waterproof membrane may comprise a material that is permeable to carbon dioxide.

[0013] In some embodiments, the waterproof membrane may comprise two or more laminated thin films.

[0014] In some embodiments, the waterproof membrane may include a first layer of a porous type and a second layer of a non-porous type.

[0015] In some embodiments, the first layer may include a fluorine-based polymer film, and the second layer may include a silicon-based polymer film.

[0016] In some embodiments, the device may further include an external collector connected to the check valve so as to be in gas communication with the check valve and configured to collect gas discharged from the check valve. In this case, a waterproof membrane may not be included at the end of the conduit portion.

[0017] Another aspect of the present invention provides a secondary battery including a stacked electrode assembly in which a plurality of unit cells are stacked in a first direction, extending in a second direction perpendicular to the first direction and having electrode leads at ends; a multifunctional terminal block (MTB) coupled to the electrode leads of the stacked electrode assembly; and a laminate sheet wrapping the stacked electrode assembly together with the MTB to define an internal space of the cell. The MTB includes an electrode terminal portion electrically connected to the electrode leads of the stacked electrode assembly; a bus bar electrically connecting the electrode leads and the electrode terminal portion; and a check valve configured to discharge gas in the internal space of the cell exceeding a first pressure. The check valve includes a conduit portion communicating with the internal space of the cell and opening to the outside of the secondary battery; and a waterproof membrane provided at an outer end of the conduit portion.

[0018] In some embodiments, the waterproof membrane may comprise a hydrophobic material.

[0019] In some embodiments, the waterproof membrane may have a CO2:N2 permeability ratio of 4:1 to 50:1 as measured according to DIN 53536.

[0020] The secondary battery according to embodiments of the present invention has the effect of effectively discharging gas generated internally and preventing moisture penetration.

[0021] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0022] Figure 1a is a perspective view showing the main part of a secondary battery according to one embodiment of the present invention.

[0023] Figure 1b is a partial perspective view showing an enlarged portion of a part of the secondary battery of Figure 1a.

[0024] Figure 2 is a schematic perspective view showing the appearance of the laminate sheet removed from the secondary battery of Figure 1.

[0025] Figure 3 is a schematic diagram showing a cross-section of the first MTB cut along a plane perpendicular to the third direction and passing through the electrode terminal portion.

[0026] Figure 4a is a cross-sectional view showing a check valve according to one embodiment of the present invention.

[0027] Fig. 4b is a cross-sectional view showing the check valve in an open state.

[0028] FIG. 5 is a partially exploded perspective view showing a method of bonding laminate sheets of a secondary battery according to one embodiment of the present invention.

[0029] Figure 6 is a partial cross-sectional view of a laminate sheet according to one embodiment of the present invention.

[0030] Figure 7a is a perspective view showing a main part of a secondary battery according to one embodiment of the present invention.

[0031] Figure 7b is a partial perspective view showing an enlarged portion of a part of the secondary battery of Figure 7a.

[0032] Figure 8 is a side view of a secondary battery according to another embodiment of the present invention.

[0033] Figure 9 is a perspective view showing the main part of a secondary battery according to another embodiment of the present invention.

[0034] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention may be modified in various different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. It is preferable to interpret that the embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art. Like numbers refer to like elements throughout. Furthermore, various elements and areas in the drawings are schematically drawn. Therefore, the present invention is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0035] While terms like "first" and "second" may be used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, a first component could be referred to as a "second component," and vice versa, without departing from the scope of the present invention.

[0036] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the inventive concept. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the expressions "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, operations, components, parts, or combinations thereof.

[0037] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Furthermore, it is to be understood that commonly used terms, such as those defined in dictionaries, should be interpreted to have a meaning consistent with their meaning within the relevant technical context, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0038] In some embodiments, where implementations are otherwise feasible, specific process sequences may be performed in a different order than described. For example, two processes described in succession may be performed substantially simultaneously, or in a reverse order from the described order.

[0039] In the accompanying drawings, variations in the shapes depicted may be expected, for example, depending on manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as being limited to the specific shapes of the regions depicted herein, but should include, for example, changes in shapes resulting from the manufacturing process. All terms "and / or" used herein include each and every combination of one or more of the mentioned components. In addition, the term "substrate" used herein may mean the substrate itself, or a laminated structure including the substrate and a predetermined layer or film formed on the surface thereof. In addition, the "surface of the substrate" in this specification may mean the exposed surface of the substrate itself, or the outer surface of a predetermined layer or film formed on the substrate.

[0040]

[0041] (Example 1)

[0042] Fig. 1a is a perspective view showing the main part of a secondary battery (100) according to one embodiment of the present invention. Fig. 1b is a partial perspective view showing an enlarged portion of a part of the secondary battery (100) of Fig. 1a. Fig. 2 is a schematic perspective view showing the secondary battery (100) of Fig. 1a with the laminate sheet (130) removed.

[0043] In the drawings below, the secondary battery (100) is illustrated as being defined in a vertical coordinate system defined by a first direction along the X-axis, a second direction along the Y-axis, and a third direction along the Z-axis, which are perpendicular to each other, but the first direction, the second direction, and the third direction are not particularly limited as long as they are relatively perpendicular to each other.

[0044] Referring to FIGS. 1a to 2, the secondary battery (100) includes a stacked electrode assembly (110), a multifunctional terminal block (MTB) (120a, 120b), and a laminate sheet (130).

[0045] The stacked electrode assembly (110) may include a plurality of unit cells (111) stacked in a first direction (e.g., X-axis direction). Each of the unit cells (111) may have an electrode material applied on a metal foil that acts as a current collector.

[0046] Each of the unit cells (111) may have a thin plate-shaped body extending in a second direction (e.g., the Y-axis direction). Each of the unit cells (111) may be a positive electrode unit cell or a negative electrode unit cell. In some embodiments, the plurality of unit cells (111) may be formed by alternately stacking positive electrode unit cells and negative electrode unit cells one by one. The positive electrode unit cell and the negative electrode unit cell may be separated from each other by a separator.

[0047] In some other embodiments, the plurality of unit batteries (111) may be formed by alternately stacking a plurality of positive unit batteries and a plurality of negative unit batteries. The plurality of positive unit batteries and the plurality of negative unit batteries may be separated from each other by a separator.

[0048] The stacked electrode assembly (110) may have electrode leads (116) at both ends in the second direction (e.g., Y-axis direction). The electrode leads (116) may be electrically connected to electrode tabs of the plurality of unit cells (111). One or more electrode tabs may be connected to one electrode lead (116). In some embodiments, two or more electrode tabs may be connected to one electrode lead (116).

[0049] In some embodiments, the stacked electrode assembly (110) may have two electrode leads (116) on one side and two electrode leads (116) on the other side. In this case, half of the plurality of unit cells (111) included in the stacked electrode assembly (110) may be coupled to the first electrode lead on one side and coupled to the second electrode lead on the other side. In addition, the remaining half of the plurality of unit cells (111) included in the stacked electrode assembly (110) may be coupled to the third electrode lead on one side and coupled to the fourth electrode lead on the other side. However, the present invention is not limited thereto.

[0050] In some embodiments, the stacked electrode assembly (110) may have one or more electrode leads on one side. In some embodiments, the stacked electrode assembly (110) may have one or more electrode leads on the other side.

[0051] A first MTB (120a) may be provided at one end of the stacked electrode assembly (110) in the second direction (e.g., Y-axis direction), and a second MTB (120b) may be provided at the other end. One of the first MTB (120a) and the second MTB (120b) may be electrically connected to the cathode side of the stacked electrode assembly (110), and the other may be electrically connected to the anode side of the stacked electrode assembly (110). The second MTB (120b) may have substantially the same configuration as the first MTB (120a) except for the polarity. Hereinafter, the first MTB (120a) will be described, but a person skilled in the art will be able to understand the configuration of the second MTB (120b) therefrom.

[0052] The above first MTB (120a) may include an MTB housing (122), an electrode terminal portion (124) accommodated within the MTB housing (122), and a bus bar (125) (see FIG. 3) electrically connecting the electrode terminal portion (124) and the electrode lead (116).

[0053] The above MTB housing (122) may be made of a material having relatively high rigidity, such as metal, and defines the outer periphery of the first MTB (120a). In some embodiments, the MTB housing (122) may be made of aluminum (Al), nickel (Ni), iron (Fe), cobalt (Co), chromium (Cr), manganese (Mn), or an alloy containing one or more of these.

[0054] The MTB housing (122) may include a through hole (122h) exposing the electrode terminal portion (124) described below. The through hole (122h) may be provided in the MTB housing (122) so that the electrode terminal portion (124) is exposed toward the second direction (e.g., Y-axis direction). Therefore, the through hole (122h) may be provided on a plane perpendicular to the second direction (e.g., Y-axis direction) of the MTB housing (122). In addition, the through hole (122h) may have an opening that is open in the longitudinal direction of the electrode assembly (110). The shape of the through hole (122h) may be configured to match the outer shape of the portion where the electrode terminal portion (124) is exposed to the outside.

[0055] A person skilled in the art will understand that the first MTB (120a) may further include, as necessary, a through hole for a venting disc, a through hole for a check valve, and a through hole for an electrolyte injection port, as described later.

[0056] The electrode terminal portion (124) is accommodated within the MTB housing (122) and can be exposed through the through hole (122h). The electrode terminal portion (124) can be made of a metal or metal alloy having low electrical resistance, and can be, for example, an alloy containing copper (Cu), aluminum (Al), nickel (Ni), iron (Fe), platinum (Pt), manganese (Mn), or one or more thereof.

[0057] In some embodiments, the exposed surface of the electrode terminal portion (124) facing outward from the MTB housing (122) may be a plane. In some embodiments, the exposed surface may have a plane extending perpendicular to the second direction (e.g., the Y-axis direction).

[0058] In some embodiments, an electrically insulating spacer may be provided between the electrode terminal portion (124) and the MTB housing (122) so that the electrode terminal portion (124) is electrically insulated from the MTB housing (122).

[0059] In some embodiments, the first MTB (120a) may include a venting disk (126) configured to rupture when the internal pressure of the secondary battery (100) excessively increases, thereby releasing gas that causes the excessively increased internal pressure. The venting disk (126) is not restored to its original state when it ruptures due to a thermal event occurring within the secondary battery (100). The venting disk (126) may be any venting disk known in the art and is not particularly limited.

[0060] In some embodiments, the first MTB (120a) may further include a check valve (128). The check valve (128) may be configured to open to discharge internal gas when the internal pressure of the secondary battery (100) becomes higher than a predetermined first pressure, and to close again when the internal pressure is relieved by the discharge of the gas, for example, when it becomes lower than the first pressure. Since the check valve (128) does not have a part that is ruptured by the discharge of the gas, it can be restored to its original state after the discharge of the internal gas. The check valve (128) will be described in more detail below.

[0061] In some embodiments, the first MTB (120a) may further include an electrolyte injection port (127) capable of injecting an electrolyte. In some embodiments, the electrolyte injection port (127) may be provided in only one of the first MTB (120a) and the second MTB (120b).

[0062] The electrolyte injected through the electrolyte injection port (127) may be an electrolyte used for a typical lithium secondary battery, and is not particularly limited.

[0063] A bus bar may be further provided within the above first MTB (120a). Fig. 3 is a schematic diagram showing a cross-section of the first MTB (120a) cut along a plane passing through the electrode terminal portion (124) and perpendicular to a third direction (e.g., the Z-axis direction).

[0064] Referring to FIG. 3, the bus bar (125) may be provided to make surface contact with the electrode terminal portion (124). The bus bar (125) may be made of a metal material having low electrical resistance. In some embodiments, the bus bar (125) may be made of copper (Cu), nickel (Ni), aluminum (Al), iron (Fe), cobalt (Co), platinum (Pt), molybdenum (Mo), tin (Sn), palladium (Pd), or an alloy including one or more of these.

[0065] The bus bar (125) may be configured to make surface contact with the electrode lead (116) of the stacked electrode assembly (110). In some embodiments, the bus bar (125) may be joined to the electrode lead (116) by welding. In some embodiments, the bus bar (125) may be joined to the electrode lead (116) by a fastener, for example, by a rivet.

[0066] In some embodiments, the bus bar (125) may include a center portion (125c) having a planar shape extending horizontally in the first direction (e.g., X-axis direction) and an edge portion (125e) extending by bending from the center portion (125c). The center portion (125c) may be configured to form a generally U-shaped cross-sectional shape together with the edge portion (125e) and may extend in the third direction (e.g., Z-axis direction). In some embodiments, the edge portion (125e) may have a plane extending perpendicularly to the first direction (e.g., X-axis direction).

[0067] The above bus bar (125) can make surface contact with the electrode terminal portion (124) at the center portion (125c). The above bus bar (125) can make surface contact with the electrode lead (116) at the edge portion (125e).

[0068] In some embodiments, the electrode lead (116) may include a pre-bended portion that is bent at a portion that does not contact the bus bar (125). The pre-bended portion may prevent stress from being concentrated at a specific portion of the electrode lead (116) due to an external force applied to the stacked electrode assembly (110), thereby improving safety.

[0069] Since the secondary battery (100) of the present invention accommodates all units having respective functions within the MTB (120a, 120b), such as an electrode terminal portion (124), a bus bar (125), a venting disk (126), a check valve (128), and an electrolyte injection port (127), the secondary battery itself has functions equivalent to a conventional battery module. Therefore, the secondary battery (100) of the present invention can have a high degree of freedom and compatibility, and is advantageous for implementing cell-to-pack.

[0070]

[0071] FIG. 4a is a cross-sectional view showing a check valve (128) according to one embodiment of the present invention.

[0072] Referring to FIG. 4a, the check valve may include a conduit portion (1281) extending externally through the MTB housing (122), a valve packing (1282) provided within the conduit portion (1281), and an elastic body (1283) providing a restoring force to return the valve packing to its original position.

[0073] In some embodiments, the conduit portion (1281) may be in communication with a cell interior space (IS) surrounded by the laminate sheet (130). The cell interior space (IS) may be defined by the laminate sheet (130) and the MTB housing (122).

[0074] In some embodiments, a first catch (1284) may be provided within the conduit portion (1281) on the cell interior space (IS) side. In some embodiments, a second catch (1285) may be further provided within the conduit portion (1281) spaced apart from the first catch (1284).

[0075] The above valve packing (1282) may be provided between the first catch (1284) and the second catch (1285). In addition, the elastic body (1283) may be provided between the valve packing (1282) and the second catch (1285). The second catch (1285) may limit the movement of the elastic body (1283).

[0076] The above valve packing (1282) may be configured to move toward the outside of the secondary battery (100) due to the pressure of the internal space (IS) of the cell. The outer diameter of the valve packing (1282) is smaller than the inner diameter of the conduit portion (1281), and the side surface of the valve packing (1282) may not substantially contact the inner surface of the conduit portion (1281).

[0077] The above valve packing (1282) can be moved toward the outside of the secondary battery (100) by being pressurized by the pressure of the cell internal space (IS) when the pressure of the cell internal space (IS) exceeds a predetermined pressure, for example, a first pressure. As the valve packing (1282) is moved toward the outside of the secondary battery (100) by the pressure of the cell internal space (IS), the check valve (128) can be brought into an open state. Fig. 4b is a cross-sectional view showing the check valve (128) in an open state.

[0078] Referring to FIG. 4b, the valve packing (1282) moves according to the pressure of the cell internal space (IS), and the elastic body (1283) can be compressed in accordance with the pressure of the cell internal space (IS). The gas of the cell internal space (IS) can pass through the space on the side of the valve packing (1282) and be discharged to the outside of the secondary battery (100) through the elastic body (1283).

[0079] When the pressure of the internal space (IS) of the cell becomes lower than the predetermined pressure, for example, the first pressure, the valve packing (1282) can return to its original position by the restoring force of the elastic body (1283). As the valve packing (1282) returns to its original position, the check valve (128) can be switched to a closed state.

[0080] In some embodiments, an O-ring (1287) may be provided between the valve packing (1282) and the first stopper (1284) to ensure sealing. In some embodiments, the O-ring (1287) may be fixed to the first stopper (1284). In this case, even if the valve packing (1282) is moved, the O-ring (1287) may remain on the first stopper (1284), as illustrated in FIG. 4B.

[0081] In some other embodiments, the O-ring (1287) may be fixed on the side of the valve packing (1282). In this case, the O-ring (1287) may move together with the valve packing (1282) when the check valve (128) is in an open state.

[0082] The valve packing (1282) may have a tapered side surface (1282s) so as to have a diameter that decreases toward the cell interior space (IS). The O-ring (1287) may contact the valve packing (1282), particularly at the tapered side surface (1282s). The tapered side surface (1282s) may be in a closed state by making hermetic contact with the O-ring (1287). In addition, the tapered side surface (1282s) may be spaced apart from the O-ring (1287) to form an open state.

[0083] A waterproof membrane (1288) may be provided at the end of the above conduit portion (1281). The waterproof membrane (1288) may prevent moisture such as water or water vapor from penetrating into the cell interior space (IS) through the check valve (128).

[0084] In some embodiments, the waterproof membrane (1288) may include a material that prevents moisture penetration while allowing carbon dioxide (CO2) to pass through relatively more easily. Accordingly, the waterproof membrane (1288) can smoothly discharge CO2 generated within the cell interior space (IS) to the outside.

[0085] In some embodiments, the waterproof membrane (1288) may include two or more laminated thin films. In some embodiments, the waterproof membrane (1288) may include a hydrophobic material. Specifically, the waterproof membrane (1288) may include a first layer of a porous type and a second layer of a non-porous type. The first layer may include a fluorine-based polymer film, and the second layer may include a silicon-based polymer film.

[0086] In some embodiments, the waterproof membrane (1288) may include a material that selectively transmits CO2 more readily than nitrogen (N2). For example, the waterproof membrane (1288) may include a material having a CO2:N2 permeability ratio of about 4:1 to about 50:1 as measured according to DIN 53536. If the permeability of CO2 is excessively difficult compared to N2, gas passing through the side of the valve packing (1282) may have difficulty being smoothly discharged to the outside. If the permeability of CO2 is excessively easy compared to N2, there is a risk that external gas may infiltrate into the cell interior space (IS) in the open state. In some embodiments, the CO2:N2 permeation ratio can be from about 4:1 to about 50:1, from about 5:1 to about 48:1, from about 6:1 to about 45:1, from about 7:1 to about 43:1, from about 8:1 to about 40:1, from about 9:1 to about 38:1, from about 10:1 to about 35:1, from about 11:1 to about 33:1, from about 12:1 to about 30:1, from about 13:1 to about 28:1, from about 14:1 to about 25:1, from about 15:1 to about 23:1, from about 16:1 to about 20:1, or a value between any two of these ratios.

[0087] The fluorine-based polymer film may include a perfluorinated polymer resin such as polytetrafluoroethylene (PTFE). The silicon-based polymer film may include a polymer resin such as polydimethylsiloxane (PDMS). However, the present invention is not limited thereto.

[0088] Referring again to FIGS. 1A and 2, the venting disc (126) may be configured to rupture and discharge gas from the cell interior space (IS) when the pressure in the cell interior space (IS) increases to a second pressure higher than the first pressure. As described above, once the venting disc (126) is opened to discharge gas from the cell interior space (IS), it does not return to its original state.

[0089] Fig. 5 is a partially exploded perspective view showing a method of joining a laminate sheet (130) of a secondary battery (100) according to one embodiment of the present invention. Fig. 6 is a partial cross-sectional view of a laminate sheet (130) according to one embodiment of the present invention.

[0090] Referring to FIGS. 5 and 6, the laminate sheet (130) may be configured to wrap around a side surface of the stacked electrode assembly (110). In some embodiments, the laminate sheet (130) may be attached to a side surface of the MTB (120a, 120b) so as to at least partially cover the side surface of the MTB (120a, 120b). In some embodiments, the laminate sheet (130) may cover all of the side surfaces of the MTB (120a, 120b) that are parallel to the second direction (e.g., the Y-axis direction). In some other embodiments, the laminate sheet (130) may cover only a portion of the side surfaces of the MTB (120a, 120b) that are parallel to the second direction (e.g., the Y-axis direction).

[0091] The above laminate sheet (130) may include a flexible metal layer (134), an inner resin layer (132) provided on one side of the metal layer (134), and an outer resin layer (136) provided on the other side of the metal layer (134).

[0092] The metal layer (134) can maintain an appropriate thickness and prevent water vapor, oxygen, and other gases from penetrating from the outside to the inside, and can prevent electrolyte leakage. In some embodiments, the metal layer (134) may include at least one selected from iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), and alloys thereof, but is not limited thereto. When the metal layer (134) is made of a material containing iron, the mechanical strength is strengthened, and when it is made of an aluminum material, the flexibility is improved, and thus, aluminum metal foil is mainly used.

[0093] The above metal layer (134) can be relatively easily deformed by a force applied from the outside, and can be configured to have an appropriate thickness and mechanical strength so that cracks or holes do not occur even when repeatedly deformed.

[0094] In some embodiments, the metal layer (134) can have a thickness of about 20 micrometers (μm) to about 100 μm. In some embodiments, the thickness of the metal layer (134) can have a range of about 20 μm to about 100 μm, about 25 μm to about 95 μm, about 30 μm to about 90 μm, about 35 μm to about 85 μm, about 40 μm to about 80 μm, about 45 μm to about 75 μm, about 50 μm to about 70 μm, about 55 μm to about 60 μm, or any two of these values.

[0095] The internal resin layer (132) provided on one side of the metal layer (134) may include a heat-sealing layer. In some embodiments, the internal resin layer (132) may include a polyolefin-based material capable of performing a sealing function through fusion. In some embodiments, the internal resin layer (132) may include a modified propylene such as cast polypropylene (CPP), or a polypropylene-butylene-ethylene terpolymer.

[0096] The above inner resin layer (132) can be formed by coating or laminating one side of the above metal layer (134).

[0097] The external resin layer (136) provided on the other side of the metal layer (134) can act as a base substrate and a protective layer for forming the laminate sheet (130). The external resin layer (136) can include an insulating material such as polyethylene terephthalate (PET) or nylon.

[0098] In some embodiments, the inner resin layer (132) and the outer resin layer (136) may each have a thickness of about 10 micrometers (μm) to about 50 μm. In some embodiments, the thickness of each of the inner resin layer (132) and the outer resin layer (136) may have a thickness of about 10 μm to about 50 μm, about 12 μm to about 48 μm, about 15 μm to about 45 μm, about 17 μm to about 43 μm, about 20 μm to about 40 μm, about 22 μm to about 38 μm, about 25 μm to about 35 μm, about 27 μm to about 33 μm, or a range between any two of these values.

[0099] In some embodiments, an adhesive resin layer may be further provided between the inner resin layer (132) and the metal layer (134) and / or between the outer resin layer (136) and the metal layer (134). The adhesive resin layer may be provided for smooth adhesion between different materials. The adhesive resin layer may be formed as a single layer or multiple layers. In some embodiments, the adhesive resin layer may include a polyolefin-based resin, a polyurethane-based resin, an epoxy-based resin, or a mixture thereof.

[0100] In some embodiments, the inner resin layer (132) may be fused to the side surfaces of the MTBs (120a, 120b) at both ends in the second direction (e.g., Y-axis direction). The stacked electrode assembly (110) may be encapsulated within the secondary battery by the inner resin layer (132) surrounding and fused to the side surfaces of the MTBs (120a, 120b). The inner resin layer (132) may be melted by heating while in contact with the side surfaces of the MTBs (120a, 120b) and then cooled to be fused onto the side surfaces.

[0101] The above laminate sheet (130) can be placed so that the inner resin layers (132) face each other at the joint (130m) after surrounding the side surfaces of the MTBs (120a, 120b) and the stacked electrode assembly (110), and then the inner resin layers (132) facing each other can be fused together.

[0102] The above-mentioned joining part (130m) may be positioned on any one side of the stacked electrode assembly (110). In some embodiments, the joining part (130m) may surround the stacked electrode assembly (110) and be positioned in a third direction (e.g., the Z-axis direction) of the stacked electrode assembly (110).

[0103] As described above, in the secondary battery (100) of the present invention, since the stacked electrode assembly (110) is directly surrounded by the laminate sheet (130) without a forming process for the laminate sheet (130), unit cells can be accommodated with a thickness greater than that defined in the conventional forming process. Therefore, the secondary battery (100) of the present invention is advantageous in implementing a large-capacity cell.

[0104]

[0105] (Example 2)

[0106] Fig. 7a is a perspective view showing the main part of a secondary battery (100a) according to another embodiment of the present invention. Fig. 7b is a partial perspective view showing an enlarged portion of a part of the secondary battery (100a) of Fig. 7a. Fig. 8 is a side view of a secondary battery (100a) according to another embodiment of the present invention.

[0107] The above secondary battery (100a) differs from the embodiment described with reference to FIGS. 1a to 5 in that the MTB is provided only on one side of the stacked electrode assembly extending in the second direction (e.g., the Y-axis direction). Therefore, the following description will focus on these differences, and any overlapping portions will be omitted for further explanation.

[0108] Referring to FIGS. 7A to 8, since the MTB (120c) is provided only on one side of the stacked electrode assembly, not on both sides, both electrodes of the stacked electrode assembly are connected to the MTB (120c). That is, the MTB (120c) is provided only on one side of the stacked electrode assembly in the second direction (e.g., Y-axis direction), and the joint portion (130m) can be extended without the MTB on the other side of the stacked electrode assembly in the second direction (e.g., Y-axis direction).

[0109] Since the MTB is provided on only one side of the stacked electrode assembly, the MTB (120c) is provided with a first electrode terminal portion (124a) and a second electrode terminal portion (124b) of different polarities. One of the first electrode terminal portion (124a) and the second electrode terminal portion (124b) may be a terminal portion corresponding to the cathode, and the other may be a terminal portion corresponding to the anode.

[0110] In FIG. 7b, a venting disk (126) is shown as being provided between the first electrode terminal portion (124a) and the second electrode terminal portion (124b), but the relative positions of the first electrode terminal portion (124a), the second electrode terminal portion (124b), and the venting disk (126) within the MTB (120c) are not particularly limited.

[0111] The laminated portion (130m) of the laminated sheet (130) can extend in a second direction (e.g., the Y-axis direction) from one side (the upper side in FIG. 8) in the third direction (e.g., the Z-axis direction) of the stacked electrode assembly. Furthermore, the laminated portion (130m) can extend in the third direction (e.g., the Z-axis direction) from the other side. In FIG. 8, the stacked electrode assembly is surrounded by the laminated sheet (130).

[0112]

[0113] (Example 3)

[0114] Figure 9 is a perspective view showing the main part of a secondary battery (100) according to another embodiment of the present invention.

[0115] Referring to FIG. 9, the secondary battery (100) may further include an external collector (140). The external collector (140) may be configured to collect gas discharged through the check valve (128). The external collector (140) may be connected to the check valve (128) through a gas path (142).

[0116] In some embodiments, the external collector (140) may be configured to actively suck gas discharged from the check valve (128). In this case, the external collector (140) may include a device that applies a predetermined pressure (e.g., a pressure less than the first pressure) to the end of the check valve (128).

[0117] In some embodiments, the external collector (140) may be configured to simply collect gas discharged from the check valve (128). In this case, the external collector (140) does not actively absorb gas discharged from the check valve (128).

[0118] If the above external collector (140) is provided, the waterproof membrane (1288) in the check valve (128) may be omitted.

[0119]

[0120] While the embodiments of the present invention have been described in detail above, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, modifications to future embodiments of the present invention will not depart from the scope of the invention.

[0121]

[0122] [Explanation of symbols]

[0123] 100, 100a: secondary battery

[0124] 110: Stacked electrode assembly

[0125] 111: Unit battery

[0126] 116: Electrode lead

[0127] 120a, 120b, 120c: MTB

[0128] 122: MTB Housing

[0129] 122h: Penetration hole

[0130] 124: Electrode terminal section

[0131] 125: Busbar

[0132] 125c: Center section

[0133] 125e: Edge

[0134] 126: Venting disc

[0135] 127: Electrolyte inlet

[0136] 128: Check valve

[0137] 130: Laminate sheet

[0138] 130m: Joint section

[0139] 132: Inner resin layer

[0140] 134: Metal layer

[0141] 136: Outer resin layer

[0142] 140: Catcher

[0143] 1281: Department of the Taoist Temple

[0144] 1282: Valve packing

[0145] 1283: Elastic body

[0146] 1284: First stumbling block

[0147] 1285: Second hitch

[0148] 1287: O-ring

[0149] 1288: Waterproof membrane

Claims

1. A stacked electrode assembly in which a plurality of unit cells are stacked in a first direction and have electrode leads at both ends in a second direction perpendicular to the first direction; A multifunctional terminal block (MTB) provided at least on one end of the stacked electrode assembly; and A laminate sheet wrapping the side surfaces of the stacked electrode assembly to define the internal space of the cell; Includes, The above MTB: An electrode terminal electrically connected to the electrode lead of the above stacked electrode assembly; a check valve configured to discharge gas in the internal space of the cell exceeding a first pressure; and A venting disk configured to rupture and discharge gas when the pressure in the space inside the cell increases to a second pressure exceeding the first pressure; A secondary battery containing .

2. In paragraph 1, A secondary battery characterized in that the check valve is configured to switch from a closed state to an open state when the pressure in the internal space of the cell exceeds the first pressure, and to switch from an open state to a closed state when the pressure in the internal space of the cell is relieved to be lower than the first pressure.

3. In paragraph 2, The above check valve: A conduit portion that is open to the outside of the secondary battery and communicates with the internal space of the cell; A valve packing provided within the above-mentioned conduit portion and capable of moving toward the outside of the secondary battery by the pressure of the internal space of the cell; and An elastic body that allows the valve packing to return to its original position according to the pressure in the internal space of the cell; A secondary battery characterized by including:

4. In paragraph 3, The above pipe section: A first catch provided at an end of the inner space of the cell; and A second catch provided on the inner surface of the conduit portion, spaced apart from the first catch; Including, A secondary battery characterized in that the valve packing is disposed between the first and second catches, and the elastic body is disposed between the valve packing and the second catches.

5. In paragraph 3, The above check valve includes an O-ring provided between the valve packing and the conduit portion, The valve packing includes a tapered side surface having a diameter that decreases toward the inner space of the cell, A secondary battery characterized in that the tapered side is configured to achieve the closed state by making hermetic contact with the O-ring, and the tapered side is configured to achieve the open state by being separated from the O-ring.

6. In paragraph 1, A secondary battery characterized in that the check valve further includes a waterproof membrane at the end of the conduit portion.

7. In paragraph 6, A secondary battery characterized in that the above waterproof membrane includes a material that allows carbon dioxide to pass through.

8. In paragraph 6, A secondary battery characterized in that the waterproof membrane comprises two or more laminated thin films.

9. In paragraph 8, A secondary battery characterized in that the waterproof membrane comprises a first layer of a porous type and a second layer of a non-porous type.

10. In paragraph 9, A secondary battery characterized in that the first layer includes a fluorine-based polymer film and the second layer includes a silicon-based polymer film.

11. In paragraph 1, A secondary battery characterized in that it further includes an external collector connected to the check valve so as to be in gas communication with the check valve and configured to collect gas discharged from the check valve.

12. In paragraph 11, A secondary battery characterized in that the end of the above conduit portion does not include a waterproof membrane.

13. A stacked electrode assembly in which a plurality of unit cells are stacked in a first direction, extend in a second direction perpendicular to the first direction, and have electrode leads at their ends; a multifunctional terminal block (MTB) coupled to the electrode leads of the stacked electrode assembly; and A laminate sheet surrounding the stacked electrode assembly together with the MTB to define the internal space of the cell; Includes, The above MTB is, An electrode terminal electrically connected to the electrode lead of the stacked electrode assembly; and A bus bar electrically connecting the electrode lead and the electrode terminal; and A check valve configured to discharge gas in the internal space of the cell exceeding a first pressure; Including, The above check valve: A conduit portion that is open to the outside of the secondary battery and communicates with the internal space of the cell; and A waterproof membrane provided on the outer end of the above conduit portion; A secondary battery containing:

14. In paragraph 13, A secondary battery characterized in that the above waterproof membrane includes a hydrophobic material.

15. In paragraph 13, A secondary battery characterized in that the above waterproof membrane has a CO2:N2 permeability ratio of 4:1 to 50:1 when measured according to DIN 53536.

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