Apparatus and method for pressing electrode assembly of secondary battery

Abstract

The present invention relates to an apparatus and method for attaching an electrode plate by compressing an electrode assembly of a secondary battery. The problem to be solved by the present invention is to improve the compression apparatus of a wound-type electrode assembly to resolve the above problem through good compression of the electrode assembly. To this end, the present invention comprises an electrode assembly including a first surface and a second surface opposite to the first surface, a flatness measuring unit for measuring the flatness of at least one of the first surface or the second surface of the electrode assembly, a pressing unit for compressing the first surface and the second surface of the electrode assembly, and a control unit for controlling the operation of the pressing unit according to the measurement result of the flatness measuring unit, wherein the pressing unit compresses at least one of the first surface or the second surface of the electrode assembly locally differently.

Description

Technology Field

[0001] The present invention relates to an apparatus and method for attaching electrode plates by compressing an electrode assembly of a secondary battery. Background Technology

[0003] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries capable of charging and discharging. Generally, a secondary battery includes an electrode assembly consisting of a positive electrode plate, a negative electrode plate, and a separator, and an outer casing (case, can, pouch, etc.) that houses it.

[0004] Electrode assemblies can be classified into wound and stacked types depending on the stacking form of electrode plates and separators. The wound type is called a jelly roll, and the stacked type is called a stack. Additionally, secondary batteries can be classified into pouch, cylindrical, and prismatic types depending on the material and shape of the casing.

[0005] During the manufacturing of a secondary battery, a compression process is performed to compress the electrode assembly so that the electrode plates are closely bonded to each other and the electrolyte is uniformly absorbed between the electrode plates of the electrode assembly. During compression, heating and / or charging / discharging (pre-charging) of the electrode assembly may be performed in parallel.

[0006] If the electrode plates of the electrode assembly lift or are insufficiently bonded during compression, problems such as localized undercharging and resulting adverse reactions occur.

[0007] In particular, variations in the design and material winding of the electrode assembly may result in different thicknesses depending on the location. Consequently, the electrode assembly may not be compressed uniformly across different positions during compression, leading to uneven adhesion of the electrode plates and poor electrolyte moisture retention. Furthermore, as the non-uniformity of compression across different locations increases, the severity of adverse reactions after charge-discharge cycles may worsen.

[0008] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art. The problem to be solved

[0010] The problem that the present invention aims to solve is to improve the compression device of a wound-type electrode assembly to resolve the above problem through the compression of a good electrode assembly. means of solving the problem

[0012] A compression device for an electrode assembly of a secondary battery according to one aspect of the present invention for solving the above-described problem comprises: an electrode assembly including a first surface and a second surface opposite to the first surface; a flatness measuring unit for measuring the flatness of at least one of the first surface or the second surface of the electrode assembly; a pressing unit for compressing at least one of the first surface and the second surface of the electrode assembly; and a control unit for controlling the operation of the pressing unit according to the measurement result of the flatness measuring unit, wherein the pressing unit compresses at least one of the first surface or the second surface of the electrode assembly with different pressures in each zone.

[0013] A compression device for an electrode assembly of a secondary battery according to another aspect of the present invention for solving the above-described problem comprises: an electrode assembly including a first surface and a second surface opposite to the first surface; a flatness measuring unit for measuring the flatness of at least one of the first surface or the second surface of the electrode assembly; a pressing unit for compressing at least one of the first surface and the second surface of the electrode assembly; and a control unit for controlling the operation of the pressing unit according to the measurement result of the flatness measuring unit, wherein the flatness measuring unit comprises: a pressure sensing member made of an electronic pressure sensing sheet disposed between at least one of the first surface or the second surface of the electrode assembly and a first pressing plate of the pressing unit; a detection unit for detecting the flatness of at least one of the first surface or the second surface of the electrode assembly from the pressure sensing member; and a judgment unit for determining the compression force of the pressing unit according to the flatness detection result of the pressure sensing member detected by the detection unit. The apparatus comprises: a first pressure plate for compressing the pressure sensing member; a second pressure plate for compressing the opposite side of the first or second surface of the electrode assembly where the flatness measuring part was placed; and a third pressure plate for compressing the surface of the first or second surface of the electrode assembly where the flatness measuring part was placed, wherein the third pressure plate comprises a plurality of operating parts for compressing at least one of the first or second surfaces of the electrode assembly; and a support member for supporting the operating parts.

[0014] A method for compressing an electrode assembly of a secondary battery according to another aspect of the present invention for solving the above-described problem comprises: a step of providing a secondary battery comprising an electrode assembly having a first surface and a second surface opposite to the first surface; a flatness measurement step of measuring the flatness of the electrode assembly; and an electrode assembly compression step of compressing at least one of the first surface or the second surface of the electrode assembly.

[0015] However, the technical problems and means of solution that the present invention aims to solve are not limited to the above-mentioned contents, and other unmentioned problems and means of solution can be clearly understood by those skilled in the art from the description of the invention below. Effects of the invention

[0017] According to the improved electrode assembly compression device and method of the present invention, the electrode assembly can be compressed evenly to increase the bonding degree of the electrode plate and improve the flatness of the electrode assembly, thereby resolving various problems caused by poor bonding degree of the electrode plate and flatness of the electrode assembly.

[0018] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below. Brief explanation of the drawing

[0020] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in the drawings. FIG. 1 schematically illustrates an electrode assembly of a secondary battery according to an embodiment of the present invention. FIG. 2 schematically shows a pouch-type battery according to one embodiment of the present invention. Figure 3 is a schematic diagram of a general device for compressing an electrode assembly of a pouch-type battery. FIG. 4 is a schematic diagram of a device for compressing a pressure sensing member in a pouch-type battery according to an embodiment of the present invention. FIG. 5 is a schematic diagram showing the configuration of a flatness measuring unit according to an embodiment of the present invention. Figure 6 is a schematic diagram of a device for compressing an electrode assembly of a pouch-type battery. FIG. 7 is a schematic diagram of a device for compressing an electrode assembly in a pouch-type battery according to an embodiment of the present invention. FIG. 8 is a schematic diagram of a device for compressing a pressure sensing member in a pouch-type battery according to another embodiment of the present invention. FIG. 9 is a schematic diagram showing the configuration of a flatness measuring unit according to another embodiment of the present invention. FIGS. 10 and FIGS. 11 are flowcharts illustrating a compression method of an electrode assembly compression device according to other embodiments of the present invention. Specific details for implementing the invention

[0021] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0022] Additionally, as used herein, “comprise, include” and / or “comprising, including” specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups thereof.

[0023] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0024] The statement that two subjects of comparison are "identical" means that they are "substantially identical." Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0025] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0026] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0027] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0028] Furthermore, where one component is described as being "on," "connected to," or "coupled to" another component, it should be understood that while the components may be directly connected or coupled to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "coupled" through another component.

[0029] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Additionally, the use of “may” when describing embodiments of the invention relates to “one or more embodiments of the invention.” Expressions such as “one or more” and “one or more” preceding a list of elements modify the entire list of elements and do not modify individual elements of the list.

[0030] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less, unless specifically stated otherwise.

[0031] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group of A, B, and C", or "at least one selected from A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any suitable combination.

[0032] The term "use" may be considered synonymous with the term "utilize." As used herein, terms such as "substantially," "about," and similar terms are used as terms of approximation rather than degree, and are intended to account for the inherent variation of a measured or calculated value that would be recognized by a person skilled in the art.

[0033] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Accordingly, the first element, component, region, layer, or section discussed below may be named the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0034] For ease of explanation in describing the relationship between one element or feature and another element(s) or feature(s) as illustrated in the drawings, spatial relative terms such as "beneath," "below," "lower," "above," and "upper" may be used in the specification. Spatially relative positions are to be understood as encompassing different orientations of the device in use or operation, in addition to the orientations depicted in the figures. For example, if the device in the drawing is inverted, the other element is understood as "below" or "below," and the described element is understood as "above" or "upper" of the other element. Thus, the term "below" may encompass both the up and down directions.

[0035] The terms used in this specification are for describing embodiments of the invention and are not intended to limit the invention.

[0037] FIG. 1 schematically illustrates a secondary battery electrode assembly that can be the subject of the electrode assembly compression device and method according to the present invention.

[0038] FIG. 1 shows a so-called winding type electrode assembly. However, other types of electrode assemblies not illustrated, such as stack type and Z-stack type electrode assemblies, can also be subject to compression by the electrode assembly compression device and method according to the present invention.

[0039] The electrode assembly (10) illustrated in FIG. 1 includes a first surface and a second surface opposite to the first surface, and can be formed by winding a laminate of a first electrode plate (11), a separator (12), and a second electrode plate (13).

[0040] The first electrode plate (11) of the electrode assembly (10) can act as a negative electrode and the second electrode plate (13) can act as a positive electrode, and the opposite is also possible.

[0041] The first electrode plate (11) is formed by applying a first electrode active material, such as graphite or carbon, to a first substrate formed of a metal foil such as copper, copper alloy, nickel, or nickel alloy, and may include a first electrode tab (or first uncoated portion) (14), which is an area where the first electrode active material is not applied.

[0042] The first electrode tab (14) can be connected to an external first terminal (see FIG. 3a, 3b).

[0043] In some examples, the first electrode tab (14) may be formed by cutting it to protrude to one side when manufacturing the first electrode plate (11), or it may be formed to protrude further to one side than the separator (12) without separate cutting.

[0044] The second electrode plate (13) is formed by applying a second electrode active material, such as a lithium transition metal oxide, to a substrate formed of a metal foil such as aluminum or an aluminum alloy, and may include a second electrode tab (or second uncoated portion) (15), which is an area where the second electrode active material is not applied.

[0045] The second electrode tab (15) can be connected to an external second terminal (see FIG. 3a, 3b).

[0046] In some examples, the second electrode tab (15) may be formed by cutting it to protrude to the other side when manufacturing the second electrode plate (13), and may protrude further to the other side than the separator (12) without separate cutting.

[0047] The separator (12) functions to prevent short circuits between the first electrode plate (11) and the second electrode plate (13) while allowing the movement of lithium ions.

[0048] The separator (12) may be composed of, for example, a polyethylene film, a polypropylene film, a polyethylene-polypropylene film, etc.

[0049] In the case of a pouch-type secondary battery, the electrode assembly (10) can be accommodated in a pouch of a flexible material in the form shown in FIG. 2.

[0050] A material that can be used in the above electrode assembly is described.

[0051] As the positive electrode active material, a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound) can be used.

[0052] Specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0053] The above composite oxide may be a lithium transition metal composite oxide, and specific examples include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0054] As an example, a compound represented by any one of the following chemical formulas may be used. Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Lia Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0055] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 is Mn, Al, or a combination thereof.

[0056] A positive electrode for a lithium secondary battery may include a current collector (substrate) and a positive electrode active material layer formed on the current collector.

[0057] The above positive active material layer includes a positive active material and may further include a binder and / or a conductive material.

[0058] The content of the positive active material is 90% to 99.5% by weight with respect to 100% by weight of the positive active material layer, and the content of the binder and the conductive material may each be 0.5% to 5% by weight with respect to 100% by weight of the positive active material layer.

[0059] Al can be used for the above-mentioned current collector, but is not limited thereto.

[0060] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0061] A material capable of reversibly intercalating / deintercalating the above lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof.

[0062] Examples of the above-mentioned crystalline carbon include graphite such as natural graphite or artificial graphite, and examples of the above-mentioned amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0063] As a material capable of doping and undoping the above lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The above Si-based negative electrode active material is silicon, a silicon-carbon composite, or SiO₂. x (0 <x<2), Si계 합금, 또는 이들의 조합일 수 있다.

[0064] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles.

[0065] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0066] A negative electrode for a lithium secondary battery comprises a current collector and a negative electrode active material layer located on the current collector. The negative electrode active material layer comprises a negative electrode active material and may further comprise a binder and / or a conductive material.

[0067] For example, the negative electrode active material layer may comprise 90% to 99% by weight of negative electrode active material, 0.5% to 5% by weight of binder, and 0% to 5% by weight of conductive material.

[0068] As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used. When an aqueous binder is used as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included.

[0069] As the above-mentioned cathode current collector, a material selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof may be used.

[0070] The electrolyte for lithium secondary batteries contains a non-aqueous organic solvent and a lithium salt.

[0071] The above-mentioned non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0072] The above-mentioned non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof, and may be used alone or in a mixture of two or more types.

[0073] In addition, when using carbonate-based solvents, cyclic carbonates and chain carbonates can be mixed and used.

[0074] Depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. As such a separator, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used.

[0075] The above separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0076] The above organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0077] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include, but is not limited to, inorganic particles selected from SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0078] The above organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.

[0080] Figure 2 schematically shows a pouch-type battery manufactured by housing an electrode assembly in a pouch.

[0081] A pouch-type battery may be composed of an electrode assembly (10) and a pouch (20) that accommodates the electrode assembly (10).

[0082] The first electrode tab (14) and the second electrode tab (15) of the electrode assembly (10) as shown in FIG. 2 can be electrically connected by welding to the external first terminal lead (16) and the second terminal lead (17), respectively. A tab film (18) for insulation from the pouch (20) can be attached to the first terminal lead (16) and the second terminal lead (17).

[0083] In the illustrated embodiment, the pouch (20) includes a first piece (21) having a cell receiving portion (24) and a gas collecting portion (26) formed therein, and a second piece (22) that covers the first piece (21) and seals the outer edges of the cell receiving portion (24) and the gas collecting portion (26). After placing the electrode assembly (10) into the cell receiving portion (24) and introducing the electrolyte, the outer edges of the first piece (21) and the second piece (22) are sealed.

[0084] At this time, at least some area between the cell receiving portion (24) and the gas collecting portion (26) is not sealed so that the electrolyte and gas can pass through each other. In this state, a compression process is performed to compress the electrode assembly (10) so that the electrolyte is uniformly absorbed between the electrode plates of the electrode assembly (10). During compression, heating and / or charging and discharging of the electrode assembly (10) may be performed in parallel.

[0085] When the compression process is completed, the space between the cell receiving portion (24) and the gas collecting portion (26) is sealed, and the sealing portion is cut to remove the gas collecting portion (26).

[0087] Figure 3 is intended to explain the concept of compressing the electrode assembly of a pouch-type battery.

[0088] As mentioned above, in the semi-finished state before the cell receiving portion (24) and the gas collecting portion (26) of the pouch (20) are separated, both sides of the cell receiving portion (24) can be compressed by the first pressure plate (41) and the second pressure plate (42). The pressure surface of the first pressure plate (41) and the pressure surface of the second pressure plate (42) compress the cell receiving portion (24) of the pouch (20) from both sides. The gas collecting portion (26) of the pouch (20) is outside the compression area of ​​the pressure surfaces of the first pressure plate (41) and the second pressure plate (42).

[0089] As the cell receiving portion (24) is compressed, the internal electrode assembly (10) is compressed, thereby improving the electrode plate bonding strength and allowing the electrolyte to be uniformly absorbed between the electrode plates.

[0090] Heating and pre-charging can be performed simultaneously when the electrode plate is compressed. Gas generated during compression and pre-charging of the electrode assembly (10) can be collected in the gas collection unit (26). This is because there is no seal (28) between the cell receiving unit (24) and the gas collection unit (26).

[0091] After the compression of the electrode assembly (10) is completed, the space between the cell receiving portion (24) and the gas collecting portion (26) is completely sealed, and the gas collecting portion (26) is cut off to complete the pouch-type secondary battery.

[0093] FIG. 4 is a schematic diagram of a device for measuring the flatness of an electrode assembly (10) as the first step of electrode assembly compression.

[0094] The flatness measuring unit (30) measures the flatness of at least one of the first surface (10_1) or the second surface (10_2) of the electrode assembly (10).

[0095] The flatness measuring unit (30) is placed between the first surface (10_1) or the second surface (10_2) of the electrode assembly (10) where flatness measurement is required and the pressure plate (41 or 42), and can be removed when measurement is completed.

[0096] Hereinafter, the flatness measuring unit (30) is described as being positioned between the first surface (10_1) and the first pressure plate (41) for easy explanation of the present invention. That is, the first pressure plate (41) is utilized as a pressure means for measuring the flatness of the electrode assembly (10).

[0097] This flatness measuring unit (30) may include a pressure sensing member (31), a detection unit (32), and a judgment unit (35).

[0099] FIG. 5 is a schematic diagram showing the configuration of a flatness measuring unit (30) according to an embodiment of the present invention, and FIG. 6 is a schematic diagram of a device for compressing an electrode assembly of a pouch-type battery.

[0100] As mentioned above, the pressure sensing member (31) can be positioned between the first surface (10_1) of the electrode assembly (10) and the first pressure plate (41 in FIG. 4). The pressure sensing member (31) comes into contact with the first surface (10_1) of the electrode assembly (10) by the first pressure plate (41) and can detect the pressure applied to the first surface (10_1) of the electrode assembly (10) in multiple zones.

[0101] In one embodiment of the present invention, the pressure-sensing member (31) may be implemented as a pressure-sensitive film. The pressure-sensing member (31) implemented as a pressure-sensing film may display different colors and / or different concentrations of specific colors depending on the different flatness of each section area of ​​the electrode assembly (10) according to the pressure applied from the first pressure plate (41). Since the thickness or flatness of the electrode assembly (10) may be non-uniform depending on the location due to the design of the electrode assembly (10) and the material winding state, the color or concentration appearing on the pressure-sensing film will be displayed differently due to the pressure difference in each section of the electrode assembly (10). For example, the pressure-sensing film may display a darker red or a darker concentration as the pressure applied from the first pressure plate (41) to a specific section area of ​​the electrode assembly (10) is higher, and a darker blue or a lighter concentration as the pressure is lower.

[0102] The detection unit (32) can detect a change in color and / or concentration appearing on the pressure sensing member (31) and output pressure distribution information of the first surface (10_1) of the electrode assembly (10) as an electrical signal. Then, the detection unit (32) transmits the pressure distribution information to the judgment unit (35).

[0103] In some embodiments, the detection unit (32) may be composed of a color sensor (33) and / or a concentration sensor (34).

[0104] The color sensor (33) detects the color displayed on the pressure sensing member (31), which is made of a pressure sensing film, and converts it into a corresponding electrical signal. The color sensor (33) can be implemented as an imaging element such as a CCD or CMOS.

[0105] The concentration sensor (34) can detect changes in concentration of a pressure sensing member (31) made of a pressure sensing film in an optical manner. For example, the concentration sensor (34) can detect changes in concentration by irradiating light onto the pressure sensing member (31) and measuring the intensity of the light that is reflected or transmitted. The concentration sensor (34) can also be implemented as an imaging element such as a CCD or CMOS in addition to an optical method.

[0106] The judgment unit (35) determines the compression force of the pressure unit (first or second pressure plate) based on the flatness detection signal (e.g., color and / or density distribution) of the pressure sensing member (31) received from the detection unit (32). Then, the judgment unit (35) transmits the determined compression force to the control unit (50 in FIG. 7).

[0107] This judgment unit (35) may include an algorithm that tracks changes in color and / or concentration transmitted from the detection unit (32) and dynamically adjusts the pressure applied by the pressurizing unit to the electrode assembly (10).

[0109] FIGS. 6 and FIGS. 7 schematically illustrate a mechanism for compressing an electrode assembly (10) after measuring the flatness of the electrode assembly (10), and FIGS. 7 is intended to explain that a control unit (50) controls the compression mechanism of FIGS. 6 according to information received from a flatness measuring unit (30).

[0110] As shown in FIG. 4, the first surface (10_1) of the electrode assembly (10) is pressed by the first pressure plate (41) using the flatness measuring unit (30) to measure the pressure in each virtual zone of the first surface (10_1) of the electrode assembly (10), and then the first pressure plate (41) and the pressure sensing member (31) are removed from the electrode assembly (10). Then, the third pressure plate (43) presses the first surface (10_1) of the electrode assembly (10) in the F1 direction (Fig. 7). At this time, the second pressure plate (42) can support or press the second surface (10_2), which is the opposite side of the first surface (10_1) where the pressure sensing member (31) of the flatness measuring unit (30) was placed in the electrode assembly (10).

[0111] The third pressure plate (43) may include a support (44) and an operating part (45). The support (44) may support a plurality of operating parts (45). The operating part (45) presses the first surface (10_1) of the electrode assembly (10) and may be composed of a plurality of parts.

[0112] The operating part (45) may be a mechatronics actuator in which the pressurizing part (not shown) moves in a different linear direction depending on the magnitude of the electrical signal (e.g., the amount of control of the control signal from the control part (50)). When the pressurizing part is close to the surface to be pressed of the electrode assembly (10), it may press the surface to be pressed with a greater pressure.

[0113] Each of the multiple operating parts (45) can be positioned at a location corresponding to a virtual partitioned area on the first surface (10_1) of the electrode assembly (10).

[0114] The total surface area of ​​the pressurized surface of the multiple operating parts (45) may be equal to or larger than the area of ​​the first surface (10_1) of the electrode assembly (10). The number of multiple operating parts (45) may vary depending on the area of ​​the electrode assembly (10). That is, if the area of ​​the first surface (10_1) of the electrode assembly (10) is large, the number of multiple operating parts (45) may be relatively large, and if the area of ​​the first surface (10_1) of the electrode assembly (10) is small, the number of multiple operating parts (45) may be relatively small.

[0115] The compression force of each of the multiple operating parts (45) may vary depending on the zone-specific color and / or concentration detected by the detection part (32) from the pressure sensing member (31). For example, when the multiple operating parts (45) compress the first surface (10_1) of the electrode assembly (10) during the flatness measurement step, the higher the concentration of the pressure sensing member (31), the higher the compression force, and the lower the concentration of the pressure sensing member (31), the lower the compression force.

[0116] In this way, since a plurality of operating parts (45) press the first surface (10_1) of the electrode assembly (10) with different pressing forces depending on the area, a uniform pressing result can be obtained despite the uneven flatness of the electrode assembly (10).

[0117] The control unit (50) shown in FIG. 7 controls the operating unit (45) of the third pressure plate (43) described above according to the measurement result of the flatness measuring unit (30). Specifically, the control unit (50) can control the pressure of each operating unit (45) by receiving the pressure determined by the judgment unit (35) of the flatness measuring unit (30) by analyzing the color and / or concentration provided from the detection unit (32) and generating a pressure control signal for the operating unit (45).

[0119] Hereinafter, an electrode assembly compression device according to another embodiment of the present invention will be described with reference to the attached drawings.

[0120] FIG. 8 is a schematic diagram of an electrode assembly flatness measuring device according to another embodiment of the present invention, and FIG. 9 is a schematic diagram showing the configuration of a flatness measuring unit according to another embodiment of the present invention.

[0121] Below, the differences from the embodiments shown in FIGS. 4 and FIGS. 5 mentioned above will be briefly explained.

[0122] First, the pressure sensing member (31') used in this embodiment is made of an electronic pressure sensing sheet containing a plurality of pressure sensors. The pressure sensing cell may be a load cell used in strain gauges or weighing scales.

[0123] In a pressure sensing member (31') made of an electronic pressure sensing sheet, the resistance, voltage, or current of each pressure sensor changes in response to the pressure applied from the first pressure plate (41), and accordingly, different electrical signals are output for each region of the pressure-contacted surface of the electrode assembly (10). For example, in the pressure sensing member (31') made of an electronic pressure sensing sheet, the strength of the electrical signal becomes stronger as the pressure applied from the first pressure plate (41) is higher, and the signal becomes weaker as the pressure is lower.

[0124] The flatness measuring unit (30') measures the flatness of at least one of the first surface (10_1) or the second surface (10_2) of the electrode assembly (10). As shown in FIG. 9, this flatness measuring unit (30') includes a pressure sensing member (31'), a detection unit (32'), and a judgment unit (35).

[0125] The detection unit (32') receives an electrical signal from a pressure sensing member (31') made of an electronic pressure sensing sheet and detects the flatness of the first surface (10_1) of the electrode assembly (10). The detection unit (32') may be configured as a circuit for profiling the pressure distribution of the first surface (10_1) of the electrode assembly (10) from the electrical signal.

[0126] The judgment unit (35) determines the compression force of each operating unit (45) of the third pressure plate (40) according to the pressure distribution profile detected by the detection unit (32') as described in FIGS. 6 and 7, and transmits the result to the control unit (50).

[0127] The configuration and operation of the third pressure plate (43) and / or second pressure plate (42) and the control unit (50) that press the first surface (10_1) of the electrode assembly (10) are similar to those described above with reference to FIGS. 6 and FIGS. 7.

[0129] Hereinafter, a method for manufacturing a secondary battery using the embodiments of the electrode assembly compression device described above will be explained.

[0130] FIGS. 10 and FIGS. 11 are flowcharts illustrating a compression method of an electrode assembly compression device according to some embodiments of the present invention.

[0131] Referring to FIG. 10, a secondary battery is provided in which an electrode assembly (10) including a first surface (10_1) and a second surface (10_2) opposite to the first surface (10_1) is housed in a pouch, and an electrolyte is injected into the pouch (S100).

[0132] Then, the flatness of the electrode assembly (10) is measured (S200).

[0133] Referring to FIG. 11, in the flatness measurement step (S200), first, a pressure sensing member (31) is placed between the electrode assembly (10) and the first pressure plate (41) of the pressure member (40) (S210). Then, the first pressure plate (41) compresses the pressure sensing member (31) (S220). Subsequently, the pressure sensing member (31) measures the flatness of the first surface (10_1) of the electrode assembly (10) (S230). When the flatness measurement is completed, the pressure sensing member (31) is removed from between the electrode assembly (10) and the first pressure plate (41) (S240).

[0134] Referring again to FIG. 10, when the flatness measurement of the electrode assembly (10) is completed, the first surface (10_1) of the electrode assembly (10) is pressed (S300).

[0135] Specifically, in the electrode assembly (10) compression step (S300), when the pressure sensing member (31) is removed between the electrode assembly (10) and the first pressure plate (41), the operating part (45) of the third pressure plate (43) compresses the first surface (10_1) of the electrode assembly (10) where flatness measurement is completed.

[0136] At this time, the present invention comprises a plurality of operating parts (45), and each of the plurality of operating parts (45) presses with different pressures for each section of the electrode assembly (10) according to the flatness measurement result.

[0137] Meanwhile, in some embodiments, the electrode assembly (10) pressing step may include at least one of supplying power to the electrode assembly (10) to charge and discharge it, and heating the electrode assembly (10). Heating, charging, discharging, and pressing the electrode assembly (10) is called HPC (heat, press, charge).

[0138] Next, the gas generated during the electrode assembly (10) compression step is collected and removed (S400).

[0139] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0141] 10 Electrode assembly, 20 Pouch, 30, 30' Flatness measuring unit, 31, 31' Pressure sensing member, 32, 32' Detecting unit, 35, 35' Judging unit, 41 First pressure plate, 42 Second pressure plate, 43 Third pressure plate, 44 Support, 45 Actuating unit, 50 Control unit

Claims

Claim 1 An electrode assembly comprising: a first surface and a second surface opposite to the first surface; a flatness measuring unit for measuring the flatness of at least one of the first surface or the second surface of the electrode assembly; a pressing unit for pressing at least one of the first surface and the second surface of the electrode assembly; and a control unit for controlling the operation of the pressing unit according to the measurement result of the flatness measuring unit, wherein the pressing unit presses at least one of the first surface or the second surface of the electrode assembly with different pressures in different zones. Claim 2 An electrode assembly compression device according to claim 1, wherein the flatness measuring part is disposed between at least one of the first or second surface of the electrode assembly and the pressing part, and is removed when the measurement is completed. Claim 3 In paragraph 2, the flatness measuring unit comprises: a pressure sensing member disposed between at least one of the first or second surfaces of the electrode assembly and the first pressure plate of the pressure member; a detection unit that detects the flatness of at least one of the first or second surfaces of the electrode assembly from the pressure sensing member; and a judgment unit that determines the compression force of the pressure member according to the flatness detection result of the pressure sensing member detected by the detection unit. Claim 4 In paragraph 3, the pressure sensing member is an electrode assembly compression device that measures pressure in each zone by dividing at least one of the first or second surfaces of the electrode assembly into multiple sections. Claim 5 In paragraph 2, the pressure sensing member is an electrode assembly compression device composed of a pressure-sensitive film. Claim 6 In claim 5, the pressure sensing film is an electrode assembly compression device that exhibits at least one of color and concentration by pressure applied from the first pressurizing member of the pressurizing part. Claim 7 In claim 6, the pressure sensing member is an electrode assembly compression device that exhibits a darker color as the pressure applied from the first pressurizing member of the pressurizing part increases and a lighter color as the pressure decreases. Claim 8 An electrode assembly compression device according to claim 6, wherein the pressure member comprises: a first pressure plate for compressing the pressure sensing member; a second pressure plate for compressing the opposite side of the first or second surface of the electrode assembly where the flatness measuring member was placed; and a third pressure plate for compressing the side of the first or second surface of the electrode assembly where the flatness measuring member was placed. Claim 9 In claim 8, the electrode assembly compression device, wherein the third pressure plate comprises a plurality of operating parts that compress at least one of the first or second surfaces of the electrode assembly. Claim 10 In claim 9, the compressive force of the operating part comprising a plurality of parts is different according to at least one of the color and concentration appearing on the pressure sensing member, an electrode assembly compressing device. Claim 11 An electrode assembly including a first surface and a second surface opposite to the first surface; a flatness measuring unit for measuring the flatness of at least one of the first surface or the second surface of the electrode assembly; a pressing unit for pressing at least one of the first surface and the second surface of the electrode assembly; and a control unit for controlling the operation of the pressing unit according to the measurement result of the flatness measuring unit, wherein the flatness measuring unit comprises: a pressure sensing member made of an electronic pressure sensing sheet disposed between at least one of the first surface or the second surface of the electrode assembly and a first pressing plate of the pressing unit; a detection unit for detecting the flatness of at least one of the first surface or the second surface of the electrode assembly from the pressure sensing member; and a judgment unit for determining the pressing force of the pressing unit according to the flatness detection result of the pressure sensing member detected by the detection unit. Claim 12 An electrode assembly compression device according to claim 11, wherein the electronic pressure sensing sheet comprises a plurality of pressure sensors, and the plurality of pressure sensors output different electrical signals depending on the pressure applied from the first pressure plate of the pressurizing part. Claim 13 In claim 12, the electronic pressure sensing sheet is an electrode assembly compression device in which the strength of the electrical signal becomes stronger as the pressure applied from the first pressure plate of the pressurizing part increases, and the signal becomes weaker as the pressure decreases. Claim 14 An electrode assembly compression device according to claim 11, wherein the pressurizing member comprises: a first pressurizing plate for compressing the pressure sensing member; a second pressurizing plate for compressing the opposite side of the first or second surface of the electrode assembly where the flatness measuring member was placed; and a third pressurizing plate for compressing the surface of the first or second surface of the electrode assembly where the flatness measuring member was placed, wherein the third pressurizing plate comprises a plurality of operating members for compressing at least one of the first or second surfaces of the electrode assembly. Claim 15 In claim 14, the compressive force of the operating part, which is composed of a plurality of parts, varies according to the electrical signal appearing on the pressure sensing member, in an electrode assembly compressing device. Claim 16 A method for manufacturing a secondary battery comprising: a step of providing a secondary battery including an electrode assembly having a first surface and a second surface opposite to the first surface; a flatness measurement step of measuring the flatness of the electrode assembly; and an electrode assembly compression step of compressing at least one of the first surface or the second surface of the electrode assembly. Claim 17 A method for manufacturing a secondary battery according to claim 16, wherein the flatness measurement step comprises: a step of placing a pressure sensing member between at least one of the first or second surfaces of the electrode assembly and a first pressure plate of the pressure member; a step of the first pressure plate compressing the pressure sensing member; a step of measuring the flatness of at least one of the first or second surfaces of the electrode assembly by the pressure sensing member; and a step of removing the pressure sensing member between the electrode assembly and the first pressure plate when the flatness measurement is completed. Claim 18 A method for manufacturing a secondary battery according to claim 17, wherein the electrode assembly compression step comprises, when the pressure sensing member is removed between the electrode assembly and the first pressure plate, the third pressure plate compresses the surface of the first or second surface of the electrode assembly where the flatness measurement is completed. Claim 19 A method for manufacturing a secondary battery according to claim 18, wherein the third pressure plate compresses the surface of the first or second surface of the electrode assembly for which the flatness measurement has been completed with different pressures in each zone according to the result of the flatness measurement. Claim 20 A method for manufacturing a secondary battery according to claim 18, wherein the electrode assembly compression step further comprises compressing the side opposite to the side on which the pressure sensing member was disposed, either the first or second side of the electrode assembly, with a second pressure plate.

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