Secondary batteries

Abstract

A secondary battery is provided, comprising: a stacked electrode assembly in which multiple unit batteries are stacked in a first direction and having 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 that wraps around the sides of the stacked electrode assembly to define the internal space of the cell.

Description

Technical Field

[0001] The present invention relates to a secondary battery, and more specifically, to a secondary battery capable of effectively discharging gas generated inside and preventing penetration of moisture.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0115109 filed on August 31, 2023, and all the contents disclosed in the Korean patent application are included as part of this specification.

Background Art

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as an energy source for various wireless devices such as handsets, notebook computers, and wireless vacuum cleaners. In recent years, due to improvements in energy density and economies of scale, the manufacturing cost per unit capacity of secondary batteries has decreased epochally, and as the cruising range of BEV (battery electric vehicle) increases to a level equivalent to that of fuel vehicles, the main application of secondary batteries has shifted from mobile devices to mobility.

[0004] On the other hand, in recent years, the demand for large-capacity battery packs applied to electric vehicles and the like has been increasing. Large-capacity battery packs mounted on automobiles are required to enhance safety along with increased capacity.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technical problem to be achieved by the present invention is to provide a secondary battery capable of effectively discharging gas generated inside and preventing penetration of moisture.

Means for Solving the Problems

[0006] To achieve the above technical objectives, the present invention provides a secondary battery comprising: a stacked electrode assembly in which a plurality of unit batteries are stacked in a first direction and having electrode leads at both ends in a second direction perpendicular to the first direction; a multifunctional terminal block (MTB) provided at least one end of the stacked electrode assembly; and a laminate sheet that wraps around the sides of the stacked electrode assembly to define the internal cell space. The MTB may include electrode terminals electrically connected to the electrode leads of the stacked electrode assembly; a check valve configured to discharge gas from the internal cell space exceeding a first pressure; and a rupture disk configured to rupture and discharge gas when the pressure in the internal cell space increases to a second pressure exceeding the first pressure.

[0007] In some embodiments, the check valve can be configured to switch from a closed state to an open state when the pressure in the cell's internal space exceeds the first pressure, and to switch from an open state to a closed state after the pressure in the cell's internal space has relaxed to a level below the first pressure.

[0008] In some embodiments, the check valve may include a conduit portion communicating with the internal space of the cell and open to the outside of the secondary battery; a valve packing provided within the conduit portion and capable of moving toward the outside of the secondary battery due to the pressure of the internal space of the cell; and an elastic body that causes the valve packing to return to its original position in response to the pressure of the internal space of the cell.

[0009] In some embodiments, the conduit portion includes a first hooking projection provided at the end facing the internal space of the cell, and a second hooking projection provided on the inner circumferential surface of the conduit portion, spaced apart from the first hooking projection, the valve packing is disposed between the first hooking projection and the second hooking projection, and the elastic body can be disposed between the valve packing and the second hooking projection.

[0010] In some embodiments, the check valve includes an O-ring provided between the valve packing and the conduit, the valve packing includes tapered sides having a diameter that decreases toward the internal space of the cell, the tapered sides forming the closed state by being in airtight contact with the O-ring, and forming the open state by separating the tapered sides 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 include a material that allows carbon dioxide to pass through.

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

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

[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, an external collector may be further included, which is connected to the check valve to communicate with gas and configured to collect the gas discharged from the check valve. In this case, the end of the conduit portion may not include a waterproof membrane.

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

[0018] In some embodiments, the waterproof membrane may include a hydrophobic substance.

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

[0020] The secondary battery according to the embodiment of the present invention has the effect of effectively discharging gas generated inside and preventing moisture from penetrating.

[0021] The effects that can be obtained from exemplary embodiments of the present invention are not limited to those mentioned above, and other effects not mentioned can be clearly derived and understood by a person of ordinary skill in the art to which the exemplary embodiments of this disclosure belong from the following description. That is, unintended effects associated with carrying out exemplary embodiments of this disclosure can also be derived by a person of ordinary skill in the art from exemplary embodiments of this disclosure. [Brief explanation of the drawing]

[0022] [Figure 1a] It is a perspective view showing a main part of a secondary battery according to an embodiment of the present invention. [Figure 1b] It is a partial perspective view showing an enlarged part of the secondary battery of Fig. 1a. [Figure 2] It is a schematic perspective view showing a state where a laminate sheet is removed from the secondary battery of Fig. 1. [Figure 3] It is a schematic view showing a cross section obtained by cutting the first MTB in a plane perpendicular to the third direction through an electrode terminal portion. [Figure 4a] It is a cross-sectional view showing a check valve according to an embodiment of the present invention. [Figure 4b] It is a cross-sectional view showing the check valve in an open state. [Figure 5] It is a partially exploded perspective view showing a bonding method of a laminate sheet of a secondary battery according to an embodiment of the present invention. [Figure 6] It is a partial cross-sectional view of a laminate sheet according to an embodiment of the present invention. [Figure 7a] It is a perspective view showing a main part of a secondary battery according to an embodiment of the present invention. [Figure 7b] It is a partial perspective view showing an enlarged part of the secondary battery of Fig. 7a. [Figure 8] It is a side view of a secondary battery according to another embodiment of the present invention as viewed from the side. [Figure 9] It is a perspective view showing a main part of a secondary battery according to another embodiment of the present invention.

Mode for Carrying Out the Invention

[0023] Preferred embodiments of the concept of the present invention will be described in detail below with reference to the accompanying drawings. However, embodiments of the concept of the present invention can be modified into various different forms, and the scope of the concept of the present invention should not be construed as being limited by the embodiments described below. It is preferable that embodiments of the concept of the present invention be construed as being provided to more fully explain the concept of the present invention to a person of average knowledge in the art. The same reference numerals mean the same element throughout. Furthermore, various elements and areas in the drawings are depicted schematically. Therefore, the concept of the present invention is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0024] Terms such as "first," "second," etc., can be used to describe various components, but such components are not limited by these terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the concept of the present invention, the first component may be named the second component, and conversely, the second component may be named the first component.

[0025] The terms used in this application are used solely to describe specific embodiments and are not intended to limit the concepts of the invention. A singular expression includes plural expressions unless the context clearly indicates otherwise. In this application, expressions such as “includes” or “has” are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and are understood not to preemptively exclude the presence or possibility of adding one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0026] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as those commonly understood by those of ordinary skill in the art to which the concepts of this invention pertain. Furthermore, terms defined in commonly used dictionaries may be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0027] Where a particular embodiment can be otherwise realized, a specific sequence of steps may be performed in a different order than that described. For example, two steps described consecutively may be performed substantially simultaneously, or in the reverse order of the description.

[0028] In the accompanying drawings, deformation of the shown shapes can be expected, for example, due to manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as being limited to specific shapes of the regions shown herein, and may include, for example, changes in shape brought about during the manufacturing process. All terms used herein, "and / or," include each of the components mentioned and all combinations of one or more of them. The term "substrate" as used herein may mean the substrate itself or a laminated structure including a predetermined layer or film formed on the substrate. The term "surface of the substrate" as used herein may mean the exposed surface of the substrate itself or an outer surface including a predetermined layer or film formed on the substrate.

[0029] (First Embodiment) Figure 1a is a perspective view showing the main parts of a secondary battery 100 according to one embodiment of the present invention. Figure 1b is a partial perspective view showing an enlarged portion of the secondary battery 100 in Figure 1a. Figure 2 is a schematic perspective view showing the secondary battery 100 in Figure 1a with the laminate sheet 130 removed.

[0030] In the following drawings, the secondary battery 100 is shown defined in a vertical coordinate system defined as a first direction along the X-axis, a second direction along the Y-axis, and a third direction along the Z-axis, all of which are perpendicular to each other. However, the first, second, and third directions only need to be perpendicular to each other and are not particularly limited.

[0031] Referring to Figures 1a to 2, the secondary battery 100 includes a stacked electrode assembly 110, multifunctional terminal blocks (MTBs) 120a and 120b, and a laminate sheet 130.

[0032] The stacked electrode assembly 110 described above may include a plurality of unit cells 111 stacked in a first direction (for example, the X-axis direction). Each of the unit cells 111 may have an electrode material coated on a metal foil that acts as a current collector.

[0033] Each unit cell 111 may have a thin, plate-like body extending in a second direction (for example, the Y-axis direction). Each unit cell 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 arranged in alternating stacks of one positive electrode unit cell and one negative electrode unit cell. The positive electrode unit cells and the negative electrode unit cells may be separated from each other by a separator membrane.

[0034] In some other embodiments, the plurality of unit cells 111 may consist of a plurality of positive electrode unit cells and a plurality of negative electrode unit cells stacked alternately. The plurality of positive electrode unit cells and the plurality of negative electrode unit cells may be separated from each other by a separator membrane.

[0035] The stacked electrode assembly 110 described above may have electrode leads 116 at both ends in the second direction (for example, the Y-axis direction). The electrode leads 116 can be electrically connected to the electrode tabs of the plurality of unit batteries 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.

[0036] 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 batteries 111 included in the stacked electrode assembly 110 may be coupled to a first electrode lead on one side and to a second electrode lead on the other side. The remaining half of the plurality of unit batteries 111 included in the stacked electrode assembly 110 may be coupled to a third electrode lead on one side and to a fourth electrode lead on the other side. However, the present invention is not limited thereto.

[0037] 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.

[0038] A first MTB 120a can be provided at one end of the stacked electrode assembly 110 in the second direction (for example, the Y-axis direction), and a second MTB 120b can be provided at the other end. One of the first MTB 120a and the second MTB 120b can be electrically connected to the cathode side of the stacked electrode assembly 110, and the other can be electrically connected to the anode side of the stacked electrode assembly 110. The second MTB 120b can have substantially the same configuration as the first MTB 120a, except for a different polarity. The first MTB 120a will be described below, from which the configuration of the second MTB 120b can be understood by an ordinary technician.

[0039] The first MTB120a described above may include an MTB housing 122, an electrode terminal portion 124 housed within the MTB housing 122, and a busbar 125 (see Figure 3) that electrically connects the electrode terminal portion 124 and the electrode lead 116.

[0040] The MTB housing 122 described above can be made of a material having relatively high rigidity, such as metal, and defines the outer edge of the first MTB 120a. In some embodiments, the MTB housing 122 can be made of aluminum (Al), nickel (Ni), iron (Fe), cobalt (Co), chromium (Cr), manganese (Mn), or an alloy containing one or more of these.

[0041] The MTB housing 122 described above may include a through hole 122h that exposes the electrode terminal portion 124, which will be described later. The through hole 122h can be provided in the MTB housing 122 such that the electrode terminal portion 124 is exposed in the second direction (for example, the Y-axis direction). Therefore, the through hole 122h can be provided on a plane of the MTB housing 122 perpendicular to the second direction (for example, the Y-axis direction). The through hole 122h may also have an opening that is open in the longitudinal direction of the electrode assembly 110. The shape of the through hole 122h can be configured to match the outer edge shape of the portion of the electrode terminal portion 124 that is exposed to the outside.

[0042] A typical engineer can understand that the first MTB120a described above may further include, as needed, through-holes for venting discs, through-holes for check valves, and through-holes for electrolyte injection ports, as described later.

[0043] The electrode terminal portion 124 is housed 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 with low electrical resistance, such as copper (Cu), aluminum (Al), nickel (Ni), iron (Fe), platinum (Pt), manganese (Mn), or an alloy containing one or more of these.

[0044] In some embodiments, the exposed surface of the electrode terminal portion 124 that is exposed to the outside from the MTB housing 122 may be a flat surface. In some embodiments, the exposed surface may have a plane that extends perpendicular to the second direction (for example, the Y-axis direction).

[0045] In some embodiments, an electrically insulating spacer can 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.

[0046] In some embodiments, the first MTB 120a may include a rupture disk 126 configured to rupture when the internal pressure of the secondary battery 100 increases excessively, thereby releasing the gas causing the excessively high internal pressure. Once the rupture disk 126 is caused by a thermal event occurring inside the secondary battery 100, it will not return to its original state. The venture disk 126 may be any venture disk known in the art and is not particularly limited.

[0047] In some embodiments, the first MTB 120a may further include a check valve 128. The check valve 128 may be configured to open to release internal gas when the internal pressure of the secondary battery 100 rises above a predetermined first pressure, and to close again when the internal pressure is relieved by the release of the gas, for example, when it falls below the first pressure. Since there is no part of the check valve 128 that will burst upon the release of the gas, it can return to its original state after releasing the internal gas. The check valve 128 will be described in more detail later.

[0048] In some embodiments, the first MTB120a may further include an electrolyte inlet 127 into which an electrolyte can be injected. In some embodiments, the electrolyte inlet 127 may be provided in only one of the first MTB120a and the second MTB120b.

[0049] The electrolyte injected through the electrolyte inlet 127 may be any electrolyte used for a typical lithium secondary battery, and is not particularly limited.

[0050] A busbar may be further provided within the first MTB120a. Figure 3 is a schematic diagram showing a cross-section of the first MTB120a cut through the electrode terminal portion 124 in a plane perpendicular to the third direction (for example, the Z-axis direction).

[0051] Referring to Figure 3, the busbar 125 can be provided so as to be in surface contact with the electrode terminal portion 124. The busbar 125 can be made of a metallic material with low electrical resistance. In some embodiments, the busbar 125 can be made of copper (Cu), nickel (Ni), aluminum (Al), iron (Fe), cobalt (Co), platinum (Pt), molybdenum (Mo), tin (Sn), palladium (Pd), or an alloy containing one or more of these.

[0052] The busbar 125 can be configured to make surface contact with the electrode lead 116 of the stacked electrode assembly 110. In some embodiments, the busbar 125 can be joined to the electrode lead 116 by welding. In some embodiments, the busbar 125 can be joined to the electrode lead 116 by fasteners, for example by rivets.

[0053] In some embodiments, the busbar 125 may include a planar center portion 125c extending horizontally in the first direction (e.g., the X-axis direction) and an edge portion 125e extending bent from the center portion 125c. The center portion 125c may be configured to form a substantially U-shaped cross-section together with the edge portion 125e and may extend in the third direction (e.g., the Z-axis direction). In some embodiments, the edge portion 125e may have a plane extending perpendicularly to the first direction (e.g., the X-axis direction).

[0054] The busbar 125 can make surface contact with the electrode terminal portion 124 at its center portion 125c. The busbar 125 can make surface contact with the electrode lead 116 at its edge portion 125e.

[0055] In some embodiments, the electrode lead 116 may include a pre-bended portion that is bent in a portion that does not come into contact with the busbar 125. The pre-bended portion can prevent stress from concentrating on a specific part of the electrode lead 116 due to external forces applied to the stacked electrode assembly 110, thereby improving safety.

[0056] The secondary battery 100 of the present invention houses all the units having their respective functions within the MTB 120a and 120b, such as the electrode terminal section 124, busbar 125, venting disk 126, check valve 128, and electrolyte inlet 127, so 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 flexibility and interchangeability, and is advantageous for realizing cell-to-pack.

[0057] Figure 4a is a cross-sectional view showing a check valve 128 according to one embodiment of the present invention.

[0058] Referring to Figure 4a, the check valve may include a conduit portion 1281 extending outward through the MTB housing 122, a valve packing 1282 provided within the conduit portion 1281, and an elastic body 1283 that provides a restoring force to return the valve packing to its original position.

[0059] In some embodiments, the conduit portion 1281 can communicate with the internal cell space IS surrounded by the laminate sheet 130. The internal cell space IS can be defined by the laminate sheet 130 and the MTB housing 122.

[0060] In some embodiments, a first hooking projection 1284 can be provided within the conduit portion 1281 on the IS side of the cell internal space. In some embodiments, a second hooking projection 1285 can be further provided within the conduit portion 1281, spaced apart from the first hooking projection 1284.

[0061] The valve packing 1282 can be provided between the first hooking projection 1284 and the second hooking projection 1285. The elastic body 1283 can also be provided between the valve packing 1282 and the second hooking projection 1285. The second hooking projection 1285 can restrict the movement of the elastic body 1283.

[0062] The valve packing 1282 can be configured to move toward the outside of the secondary battery 100 due to the pressure in the internal cell space IS. The outer diameter of the valve packing 1282 may be smaller than the inner diameter of the conduit portion 1281, and the side surface of the valve packing 1282 may not be in substantial contact with the inner surface of the conduit portion 1281.

[0063] The valve packing 1282 can be pressurized and moved toward the outside of the secondary battery 100 by the pressure in the cell internal space IS when the pressure in the cell internal space IS exceeds a predetermined pressure, for example, a first pressure. When the valve packing 1282 is moved toward the outside of the secondary battery 100 by the pressure in the cell internal space IS, the check valve 128 can be opened. Figure 4b is a cross-sectional view showing the check valve 128 in the open state.

[0064] Referring to Figure 4b, the valve packing 1282 moves due to the pressure in the cell internal space IS, and the elastic body 1283 can be compressed in proportion to the pressure in the cell internal space IS. The gas in the cell internal space IS can be discharged to the outside of the secondary battery 100 through the space on the side surface of the valve packing 1282 and the elastic body 1283.

[0065] When the pressure in the cell internal space IS falls below a predetermined pressure, for example, the first pressure, the valve packing 1282 can return to its original position due to the restoring force of the elastic body 1283. By the valve packing 1282 returning to its original position, the check valve 128 can be switched to the closed state.

[0066] In some embodiments, an O-ring 1287 can be provided between the valve packing 1282 and the first catch projection 1284 for airtightness. In some embodiments, the O-ring 1287 can be fixed to the first catch projection 1284. In this case, even if the valve packing 1282 is moved, the O-ring 1287 can remain on the first catch projection 1284, as shown in Figure 4b.

[0067] In some other embodiments, the O-ring 1287 can be fixed to the side surface of the valve packing 1282. In this case, when the check valve 128 is open, the O-ring 1287 can move together with the valve packing 1282.

[0068] The valve packing 1282 may have tapered sides 1282s such that their diameter decreases toward the internal cell space IS. The O-ring 1287 may be in contact with the valve packing 1282, particularly at the tapered sides 1282s. The tapered sides 1282s can form a closed state by making airtight contact with the O-ring 1287. Alternatively, the tapered sides 1282s can form an open state by separating from the O-ring 1287.

[0069] A waterproof membrane 1288 can be provided at the end of the conduit portion 1281. The waterproof membrane 1288 can prevent moisture such as water or water vapor from penetrating into the internal space IS of the cell through the check valve 128.

[0070] In some embodiments, the waterproof membrane 1288 may include a material that prevents moisture penetration while allowing carbon dioxide (CO2) to pass through relatively better. Therefore, the waterproof membrane 1288 can smoothly discharge CO2 generated in the internal cell space IS to the outside.

[0071] In some embodiments, the waterproof membrane 1288 may include two or more stacked thin films. In some embodiments, the waterproof membrane 1288 may include a hydrophobic material. Specifically, the waterproof membrane 1288 may include a porous first layer and a non-porous second layer. The first layer may include a fluorine-based polymer film, and the second layer may include a silicon-based polymer film.

[0072] In some embodiments, the waterproof membrane 1288 may include a material that selectively permeates CO2 more effectively than nitrogen (N2). For example, the waterproof membrane 1288 may include a material with a CO2:N2 permeation ratio of approximately 4:1 to approximately 50:1 when measured according to DIN 53536. If CO2 permeation is excessively difficult compared to N2, gas passing through the side of the valve packing 1282 may not be able to be smoothly discharged to the outside. If CO2 permeation is excessively easy compared to N2, in the open state, external gas may penetrate into the internal cell space IS. In some embodiments, the CO2:N2 transmission ratio can be approximately 4:1 to 50:1, 5:1 to 48:1, 6:1 to 45:1, 7:1 to 43:1, 8:1 to 40:1, 9:1 to 38:1, 10:1 to 35:1, 11:1 to 33:1, 12:1 to 30:1, 13:1 to 28:1, 14:1 to 25:1, 15:1 to 23:1, 16:1 to 20:1, or any two of these ratios.

[0073] The above-mentioned fluorine-based polymer film may include perfluorinated polymer resins such as polytetrafluoroethylene (PTFE). The above-mentioned silicon-based polymer film may include polymer resins such as polydimethylsiloxane (PDMS). However, the present invention is not limited to these.

[0074] Referring again to Figures 1a to 2, the venting disk 126 can be configured to rupture when the pressure in the cell's internal space IS rises to a second pressure higher than the first pressure, thereby releasing the gas from the cell's internal space IS. As described above, once the venting disk 126 is opened and releases the gas from the cell's internal space IS, it does not return to its original state.

[0075] Figure 5 is a partially exploded perspective view showing the bonding method of the laminate sheet 130 of the secondary battery 100 according to one embodiment of the present invention. Figure 6 is a partially cross-sectional view of the laminate sheet 130 according to one embodiment of the present invention.

[0076] Referring to Figures 5 and 6, the laminate sheet 130 can be configured to wrap around the sides of the stacked electrode assembly 110. In some embodiments, the laminate sheet 130 can be attached to the sides of the MTBs 120a and 120b so as to at least partially cover the sides of the MTBs 120a and 120b. In some embodiments, the laminate sheet 130 can cover the entire sides of the MTBs 120a and 120b parallel to the second direction (e.g., the Y-axis direction). In other embodiments, the laminate sheet 130 can cover only a portion of the sides of the MTBs 120a and 120b parallel to the second direction (e.g., the Y-axis direction).

[0077] The laminate sheet 130 may include a flexible metal layer 134, an internal resin layer 132 provided on one side of the metal layer 134, and an external resin layer 136 provided on the other side of the metal layer 134.

[0078] The metal layer 134 maintains an appropriate thickness, prevents water vapor, oxygen, and other gases from penetrating from the outside to the inside, and prevents leakage of the electrolyte. In some embodiments, the metal layer 134 may, but is not limited to, contain one or more selected materials from iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), and alloys thereof. When the metal layer 134 is made of a material containing iron, the mechanical strength is increased, and when it is made of aluminum, the flexibility is improved, so aluminum metal foil is usually mainly used.

[0079] The metal layer 134 described above can be deformed relatively easily by external forces, and can be configured to have an appropriate thickness and mechanical strength such that cracks or holes do not occur even with repeated deformation.

[0080] In some embodiments, the metal layer 134 may have a thickness of about 20 micrometers (μm) to about 100 μm. In some embodiments, the thickness of the metal layer 134 may be in the 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.

[0081] The internal resin layer 132 provided on one side of the metal layer 134 may include a heat-bonding layer. In some embodiments, the internal resin layer 132 may include a polyolefin material that can perform sealing by fusion. In some embodiments, the internal resin layer 132 may include modified propylene such as unoriented polypropylene (casted polypropylene: CPP), or a polypropylene-butylene-ethylene ternary copolymer.

[0082] The internal resin layer 132 can be formed by coating or laminating it to one side of the metal layer 134.

[0083] The external resin layer 136 provided on the other side of the metal layer 134 can act as a base substrate and protective layer for forming the laminate sheet 130. The external resin layer 136 may contain insulating materials such as polyethylene terephthalate (PET) or nylon.

[0084] In some embodiments, the internal resin layer 132 and the external resin layer 136 may each have a thickness of about 10 micrometers (μm) to about 50 μm. In some embodiments, the thickness of the internal resin layer 132 and the external resin layer 136 may be in the range 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 any two of these values.

[0085] In some embodiments, an adhesive resin layer may be further provided between the internal resin layer 132 and the metal layer 134, and / or between the external resin layer 136 and the metal layer 134. The adhesive resin layer may be provided for smooth adhesion between dissimilar 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 resin, a polyurethane resin, an epoxy resin, or a mixture thereof.

[0086] In some embodiments, the internal resin layer 132 can be fused to the sides of the MTB 120a and 120b at both ends in the second direction (e.g., the Y-axis direction). By fusing the internal resin layer 132 while surrounding the sides of the MTB 120a and 120b, the stacked electrode assembly 110 can be sealed inside the secondary battery. The internal resin layer 132 can be fused to the sides of the MTB 120a and 120b by heating and melting it in contact with the sides, and then cooling it.

[0087] After the laminate sheet 130 surrounds the sides of the MTB 120a and 120b and the stacked electrode assembly 110, the internal resin layers 132 are brought into close contact with each other at the joint 130m, and then the opposing internal resin layers 132 can be fused together.

[0088] The joint portion 130m can be located on any one side of the stacked electrode assembly 110. In some embodiments, the joint portion 130m can be located in a third direction (for example, the Z-axis direction) of the stacked electrode assembly 110 after enclosing it.

[0089] As described above, in the secondary battery 100 of the present invention, the laminate sheet 130 directly surrounds the stacked electrode assembly 110 without a forming process for the laminate sheet 130, so that it can accommodate unit batteries with a thickness greater than that defined by the conventional forming process. Therefore, the secondary battery 100 of the present invention is advantageous for realizing high-capacity cells.

[0090] (Second Embodiment) Figure 7a is a perspective view showing the main parts of a secondary battery 100a according to another embodiment of the present invention. Figure 7b is a partial perspective view showing an enlarged portion of the secondary battery 100a in Figure 7a. Figure 8 is a side view of the secondary battery 100a according to another embodiment of the present invention.

[0091] The secondary battery 100a described above differs from the embodiment described with reference to Figures 1a to 5 in that the MTB is provided only on one side of the stacked electrode assembly extending in the second direction (for example, the Y-axis direction). Therefore, the following description will focus on these differences, and any overlapping parts will be omitted.

[0092] Referring to Figures 7a to 8, the MTB 120c is provided on only one side of the stacked electrode assembly, rather than both sides, so that both electrodes of the stacked electrode assembly are connected to the MTB 120c. That is, the MTB 120c is provided on only one side of the stacked electrode assembly in the second direction (e.g., the Y-axis direction), and the joint 130m can be extended on the other side of the stacked electrode assembly in the second direction (e.g., the Y-axis direction) without the MTB.

[0093] 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 having opposite polarities. One of the first electrode terminal portion 124a and the second electrode terminal portion 124b may be the terminal portion corresponding to the cathode, and the other may be the terminal portion corresponding to the anode.

[0094] In Figure 7b, a venting disk 126 is shown to be 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.

[0095] The joint portion 130m of the laminate sheet 130 can be extended in a second direction (e.g., the Y-axis direction) from one side (the upper side in Figure 8) of the stacked electrode assembly in a third direction (e.g., the Z-axis direction). Furthermore, the joint portion 130m can be extended in a third direction (e.g., the Z-axis direction) from the other side. In Figure 8, the stacked electrode assembly is surrounded by the laminate sheet 130.

[0096] (Third embodiment) Figure 9 is a perspective view showing the main parts of a secondary battery 100 according to another embodiment of the present invention.

[0097] Referring to Figure 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 via a gas flow path 142.

[0098] In some embodiments, the external collector 140 may be configured to actively draw in the gas discharged from the check valve 128. In this case, the external collector 140 may include a device for applying a predetermined pressure (for example, a pressure less than the first pressure) to the end of the check valve 128.

[0099] In some embodiments, the external collector 140 can be configured to simply collect the gas discharged from the check valve 128. In this case, the external collector 140 does not actively draw in the gas discharged from the check valve 128.

[0100] When the above-mentioned external collector 140 is provided, the waterproof membrane 1288 in the check valve 128 can be omitted.

[0101] Although embodiments of the present invention have been described in detail above, any person with ordinary skill in the art to which the present invention pertains can modify and implement the present invention in various ways without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, future modifications of embodiments of the present invention will not depart from the art of the present invention. [Explanation of Symbols]

[0102] 100, 100A: Secondary battery 110: Stacked electrode assembly 111: Unit Battery 116: Electrode Leads 120a, 120b, 120c: MTB 122: MTB Housing 122h: Through hole 124: Electrode terminal part 125: Bus bar 125c: Center section 125e: Edge section 126: Venting Disc 127: Electrolyte inlet 128: Check valve 130: Laminating sheet 130m: Joint 132: Internal resin layer 134: Metal layer 136: Outer resin layer 140: Collector 1281: Conduit section 1282: Valve packing 1283: Elastic body 1284: First hooking projection 1285: Second hooking protrusion 1287: O-ring 1288: Waterproof membrane

Claims

1. A stacked electrode assembly comprising multiple unit batteries stacked in a first direction, with electrode leads at both ends in a second direction perpendicular to the first direction, A multifunctional terminal block (MTB) is provided at least one end of the stacked electrode assembly, A laminate sheet that wraps around the sides of the stacked electrode assembly so as to define the internal space of the cell, Includes, The aforementioned MTB is: The electrode terminal portion electrically connected to the electrode lead of the stacked electrode assembly, A check valve configured to discharge gas from the internal space of the cell that exceeds a first pressure, A venting disk configured to rupture and release gas when the pressure in the internal space of the cell increases to a second pressure exceeding the first pressure, Rechargeable batteries, including those mentioned above.

2. The secondary battery according to claim 1, wherein the check valve is configured to switch from a closed state to an open state when the pressure in the cell's internal space exceeds the first pressure, and to switch from the open state to a closed state after the pressure in the cell's internal space has relaxed to a level below the first pressure.

3. The aforementioned check valve is: A conduit portion that communicates with the internal space of the cell and is open to the outside of the secondary battery, A valve packing provided within the conduit portion and moving toward the outside of the secondary battery due to the pressure of the internal space of the cell, An elastic body that causes the valve packing to return to its original position in response to the pressure inside the cell, A secondary battery according to claim 2, including the following:

4. The aforementioned conduit section is: A first hooking projection provided at the end on the side of the cell's internal space, A second hooking projection is provided on the inner circumferential surface of the conduit portion, spaced apart from the first hooking projection, Includes, The secondary battery according to claim 3, wherein the valve packing is disposed between the first hooking projection and the second hooking projection, and the elastic body is disposed between the valve packing and the second hooking projection.

5. The check valve includes an O-ring provided between the valve packing and the conduit portion. The valve packing includes tapered sides having a diameter that decreases toward the internal space of the cell, The secondary battery according to claim 3 or 4, wherein the tapered side surface is configured to form the closed state by making airtight contact with the O-ring, and to form the open state by separating the tapered side surface from the O-ring.

6. The secondary battery according to claim 3, wherein the check valve further includes a waterproof membrane at the end of the conduit portion.

7. The secondary battery according to claim 6, wherein the waterproof membrane includes a material that allows carbon dioxide to pass through.

8. The secondary battery according to claim 6, wherein the waterproof membrane comprises two or more stacked thin films.

9. The secondary battery according to claim 8, wherein the waterproof membrane comprises a porous first layer and a non-porous second layer.

10. The secondary battery according to claim 9, wherein the first layer comprises a fluorine-based polymer film and the second layer comprises a silicon-based polymer film.

11. The secondary battery according to claim 3, further comprising an external collector connected to the check valve to communicate with gas and configured to collect gas discharged from the check valve.

12. The secondary battery according to claim 11, wherein the end of the conduit portion does not include a waterproof membrane.

13. A stack-type electrode assembly comprising multiple unit batteries stacked in a first direction, extending in a second direction perpendicular to the first direction, and having electrode leads at its ends, A multifunctional terminal block (MTB) coupled to the electrode leads of the stacked electrode assembly, A laminate sheet encloses the stacked electrode assembly together with the MTB so as to define the internal space of the cell, A secondary battery that includes, The aforementioned MTB is The electrode terminal portion electrically connected to the electrode lead of the stacked electrode assembly, A busbar electrically connects the electrode lead and the electrode terminal portion, A check valve configured to discharge gas from the internal space of the cell that exceeds a first pressure, Includes, The aforementioned check valve is: A conduit portion that communicates with the internal space of the cell and is open to the outside of the secondary battery, A waterproof membrane provided at the outer end of the conduit portion, Rechargeable batteries, including those mentioned above.

14. The secondary battery according to claim 13, wherein the waterproof membrane contains a hydrophobic substance.

15. The aforementioned waterproof membrane has a CO2 reading when measured according to DIN 53536. ２ : N ２ The secondary battery according to claim 13, wherein the transmittance ratio is 4:1 to 50:1.

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