Inlet structure of a liquid injection machine that injects electrolyte into cylindrical secondary batteries

Abstract

The present invention relates to an inlet structure of an injector for injecting an electrolyte into a cylindrical secondary battery and an electrolyte injection method using the same. The inlet structure of an injector for injecting an electrolyte into a battery cell includes an outer ring in a closed loop shape that defines an inner region, a momentum reducer that is spaced apart from the outer ring and disposed in the center of the inner region so as to collide with electrolyte injected through the inner region and injected into the center of the inner region, and one or more connecting members that extend from the outer ring toward the center of the outer ring and are connected to the momentum reducer.

Description

[Technical Field]

[0001] This application claims priority based on Korean Patent Application No. 10-2021-0154334 filed on November 10, 2021 and Korean Patent Application No. 10-2022-0026195 filed on February 28, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to an inlet structure of a liquid injection device that injects an electrolyte into a cylindrical secondary battery, and to an electrolyte injection method using the same. [Background technology]

[0003] In recent years, developments have been made toward increasing the size of secondary batteries (battery cells) in order to realize high energy density of battery packs and reduce manufacturing costs.

[0004] Conventional cylindrical secondary batteries typically have a structure in which tabs connecting a jelly roll to an external terminal are welded to the foil of the jelly roll. However, cylindrical secondary batteries with this structure have a limited current path and the jelly roll itself has very high resistance. While attempts have been made to reduce resistance by increasing the number of tabs connecting the jelly roll to the external terminal, simply increasing the number of tabs has limitations in terms of achieving the desired level of resistance while still ensuring a sufficient current path.

[0005] In order to reduce the resistance as the current applied to the secondary battery increases, new jelly roll structures are being developed in which the uncoated portions exposed at the axial ends of the jelly roll are bent radially to make them flat, and then connected to current collector plates by welding or other methods, and the current collector plates are connected to external terminals.

[0006] When both the positive and negative electrode plates at both axial ends of the jelly roll are to be connected to external terminals using current collectors, a method can be used in which current collectors are welded to both ends of the jelly roll, the jelly roll is then housed in a battery can, and the current collectors are then welded to the external terminals. In this case, there is enough space to weld the bottom of the battery can to the current collectors at the bottom end of the jelly roll when a welding device is inserted into the hollow portion of the jelly roll, and the hollow portion in the center of the jelly roll can be exposed without being covered by current collectors to improve electrolyte impregnation.

[0007] Furthermore, unlike conventional 18650 or 21700 size secondary batteries, the size of the secondary battery can be increased without using an insulator on the top to maximize electrical capacity.

[0008] In this way, if the hollow portion of the jelly roll is exposed by the current collector plate and no insulator is used on the top of the jelly roll, a large amount of electrolyte is injected into the hollow portion of the jelly roll by directly dropping into the large-sized secondary battery, causing a problem of deformation around the hollow portion of the jelly roll, i.e., the core portion. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide an electrolyte injection nozzle structure that can prevent deformation of the core portion of a jelly roll when electrolyte is injected into a battery can containing a jelly roll.

[0010] Another object of the present invention is to provide an electrolyte injection nozzle structure that can prevent the electrolyte from directly dropping into the hollow portion of the jelly roll while ensuring the impregnation of the electrolyte of the secondary battery.

[0011] Another object of the present invention is to provide a method for injecting an electrolyte into a jellyroll type secondary battery.

[0012] The technical object of the present invention is not limited to the above-mentioned objects, and other unmentioned objects and advantages of the present invention can be understood from the following description and can be more clearly understood from the examples of the present invention. Furthermore, it is clear that the objects and advantages of the present invention can be achieved by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0013] In order to solve the above-mentioned problems, the inlet structure of the liquid injection machine of the present invention can be installed at the electrolyte outlet of the liquid injection machine that injects electrolyte into the battery cell.

[0014] The inlet structure of the liquid injection machine can be used for a cylindrical secondary battery that accommodates a jelly-roll type electrode assembly having a hollow portion in the winding shaft.

[0015] The hollow portion of the electrode assembly may be exposed to an upper portion of a battery can of a cylindrical secondary battery.

[0016] The inlet structure of the injection machine includes: a closed-loop outer ring that defines an internal region; a momentum reducer that is spaced apart from the outer ring and disposed in the center of the internal region so as to collide with the electrolyte injected through the internal region that is injected into the center of the internal region; and one or more connecting members that extend from the outer ring toward the center of the outer ring and are connected to the momentum reducer.

[0017] The outer ring may be circular.

[0018] The connecting members may extend radially from the central portion of the outer ring.

[0019] The number of the connecting members may be one or more.

[0020] The connecting members may be provided in plurality and arranged at equal intervals along the circumferential direction.

[0021] The connecting member may include a shape that extends straight and linearly.

[0022] The connecting member may include a curved elongated shape.

[0023] The momentum reducer may be sized to cover a cross section of a hollow portion of an electrode assembly of the battery cell in which the inlet structure of the liquid injector is used.

[0024] The momentum reducer portion may have a cross section larger than a cross section of the hollow portion.

[0025] The momentum reducer may be configured to shield a central portion of the internal region.

[0026] The momentum reducer may be provided with one or more through holes having a cross section smaller than the cross section of the hollow portion of the electrode assembly of the battery cell in which the inlet structure of the liquid injector is used.

[0027] The through-hole may be circular.

[0028] The through-holes may be quadrilateral, including square, rectangular, diamond, etc.

[0029] A plurality of the through holes may be provided, and the plurality of through holes may be defined by a lattice member.

[0030] The grid members may include one or more first grid members extending in a first direction and one or more second grid members extending in a second direction intersecting the first direction.

[0031] The first and second grid members may be orthogonal to each other.

[0032] The grid member may constitute the momentum reducer and also constitute the connecting member.

[0033] The grid member may be formed not only in the momentum reducer but also over the entire inner region of the outer ring around the momentum reducer.

[0034] The outer ring, the momentum reducer, and the connecting member may be integrally molded components.

[0035] A cover ring may be further provided on the outer periphery of the outer ring, surrounding the outer ring and coupled to the outer ring.

[0036] The outer ring, the momentum reducer, the connecting member, and the cover ring may include a polymer material that is insoluble and chemically unreactive with the electrolyte.

[0037] The covering ring may be softer than the outer ring. [Effects of the Invention]

[0038] According to the present invention, a large amount of electrolyte can be rapidly injected, while preventing the core portion of the electrode assembly from being deformed due to the momentum of the electrolyte.

[0039] According to the present invention, it is possible to prevent the electrolyte from directly dropping into the hollow portion of the jelly roll, while ensuring the impregnation of the electrolyte of the secondary battery.

[0040] The above-mentioned effects and specific effects of the present invention will be described in conjunction with the following description of the preferred embodiment of the invention. [Brief explanation of the drawings]

[0041] [Figure 1] 1 is a cross-sectional view showing the internal structure of a cylindrical secondary battery to which the inlet structure of the electrolyte injection device of the present invention can be applied. [Figure 2] FIG. 2 is a perspective view of a first current collector plate of FIG. 1. [Figure 3]1 is a perspective view of an inlet structure of a liquid injection machine according to a first embodiment of the present invention. [Figure 4] FIG. 4 is a plan view of the inlet structure of the injection machine of FIG. 3. [Figure 5] FIG. 2 is a plan view of the inlet structure of the liquid injection machine according to the second to sixth embodiments of the present invention. [Figure 6] FIG. 2 is a plan view of the inlet structure of the liquid injection machine according to the second to sixth embodiments of the present invention. [Figure 7] FIG. 2 is a plan view of the inlet structure of the liquid injection machine according to the second to sixth embodiments of the present invention. [Figure 8] FIG. 2 is a plan view of the inlet structure of the liquid injection machine according to the second to sixth embodiments of the present invention. [Figure 9] FIG. 2 is a plan view of the inlet structure of the liquid injection machine according to the second to sixth embodiments of the present invention. [Figure 10] FIG. 2 is a plan view of the inlet structure of the liquid injection machine according to the second to sixth embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0042] The above-mentioned objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the technical concept of the present invention. In describing the present invention, if a detailed description of known technologies related to the present invention is deemed to obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings are used to indicate the same or similar components.

[0043] Although terms such as "first" and "second" are used to indicate various components, it is understood that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, the first component may also be the second component.

[0044] Throughout the specification, unless otherwise specified, each element may be singular or plural.

[0045] Hereinafter, when an arbitrary structure is arranged "on top (or bottom)" of a component or "above (or below)" a component, it means that the arbitrary structure is not only arranged in contact with the upper surface (or lower surface) of the component, but also that other structures may be interposed between the component and the arbitrary structure arranged above (or below) the component.

[0046] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the components may be directly coupled or connected to each other, but that other components may be "intervening" between the components, or that each component may be "coupled," "coupled," or "connected" via other components.

[0047] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. Terms such as "comprise" or "include" in this application should not be interpreted as including all of the components or steps described in the specification, but should be interpreted as meaning that some components or steps may not be included, or that additional components or steps may be included.

[0048] Furthermore, as used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. Terms such as "comprise" or "include" in this application should not be interpreted as including all of the components or steps described in the specification, but should be interpreted as meaning that some components or steps may not be included, or that additional components or steps may be included.

[0049] In the entire specification, "A and / or B" means A, B or A and B unless otherwise specified, and "C to D" means C or more and D or less unless otherwise specified.

[0050] For ease of explanation, in this specification, the direction along the length of the winding shaft of the electrode assembly wound in a jelly roll shape is referred to as the axial direction (Y). The direction surrounding the winding shaft is referred to as the circumferential direction (X). The direction toward or away from the winding shaft is referred to as the radial direction (Z). Of these, the direction toward the winding shaft is particularly referred to as the centripetal direction, and the direction away from the winding shaft is particularly referred to as the centrifugal direction.

[0051] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0052] [Cylindrical secondary battery] An example of a cylindrical secondary battery suitable for application of the inlet structure of a liquid injection device according to the present invention will be described below with reference to Figures 1 and 2. However, the inlet structure of a liquid injection device according to the present invention does not necessarily have to be applied only to the cylindrical secondary battery structure described below.

[0053] 1, a cylindrical secondary battery 1 into which an electrolyte is injected using an inlet structure of an injection device according to an embodiment of the present invention includes an electrode assembly 10, a battery can 20, a current collector plate (first current collector plate) 30, a can cover 40, and a cell terminal 50. The cylindrical secondary battery 1 may further include a seal gasket (G1), an insulating gasket (G2), a current collector plate (second current collector plate) (P), and / or an insulator (S).

[0054] The electrode assembly 10 includes a first electrode tab 11 and a second electrode tab 12 .

[0055] More specifically, the electrode assembly 10 can be manufactured by sequentially stacking a first electrode, a separator, a second electrode, and a separator at least once to form a laminate, and then winding the laminate in the X-axis direction around the Y-axis. That is, the electrode assembly 10 according to the present invention may be a jelly-roll type electrode assembly. In this case, an additional separator may be provided on the outer periphery of the electrode assembly 10 to insulate it from the battery can 20.

[0056] The first electrode includes a first electrode current collector and a first electrode active material coated on one or both surfaces of the first electrode current collector. An uncoated portion where the first electrode active material is not coated is present at one end of the first electrode current collector in the width direction (the direction corresponding to the height direction of the cylindrical secondary battery 1 shown in FIG. 1). The uncoated portion functions as a first electrode tab 11. The first electrode tab 11 is provided at the upper portion of the electrode assembly 10 housed in the battery can 20 in the height direction (the direction corresponding to the height direction of the cylindrical secondary battery 1 shown in FIG. 1). The first electrode tab 11 may be, for example, a negative electrode tab.

[0057] The second electrode includes a second electrode current collector and a second electrode active material coated on one or both surfaces of the second electrode current collector. An uncoated portion, where the second electrode active material is not coated, exists at the other end of the second electrode current collector in the width direction (the direction corresponding to the height direction of the cylindrical secondary battery 1 shown in FIG. 1). The uncoated portion functions as a second electrode tab 12. The second electrode tab 12 is provided at the lower portion in the height direction of the electrode assembly 10 housed in the battery can 20. The second electrode tab 12 may be, for example, a positive electrode tab.

[0058] In the present invention, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate may be any active material known in the art without any limitations.

[0059] In one example, the positive electrode active material has the general chemical formula A[A x M y ]O 2+z(A includes at least one element selected from Li, Na, and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, and Cr; 0≦x, 1≦x+y≦2, −0.1≦z≦2; and the stoichiometric coefficients of x, y, z, and the components included in M ​​are selected to maintain electroneutrality of the compound).

[0060] In another example, the positive electrode active material is an alkali metal compound xLiM as disclosed in US Pat. No. 6,677,082, US Pat. No. 6,680,143, etc. 1 O2-(1-x)Li2M 2 O3(M 1 contains at least one element having an average oxidation state of 3; M 2 may comprise at least one element having an average oxidation state of 4; 0≦x≦1).

[0061] In yet another example, the positive electrode active material has the general chemical formula Li a M 1 x Fe 1-x M 2 y P 1-y M 3 z O 4-z (M 1 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 contains halogen elements optionally containing F; <a≦2、0≦x≦1、0≦y<1、0≦z<1;a、x、y、z、M 1 , M 2 , and M 3wherein the stoichiometric coefficients of the components included are selected to maintain electroneutrality of the compound), or lithium metal phosphate represented by Li3M2(PO4)3, where M comprises at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg, and Al.

[0062] Preferably, the positive electrode active material may contain primary particles and / or secondary particles formed by aggregation of the primary particles.

[0063] For example, the negative electrode active material may be a carbon material, lithium metal or a lithium metal compound, silicon or a silicon compound, or tin or a tin compound. Metal oxides with a potential of less than 2 V, such as TiO2 and SnO2, may also be used as the negative electrode active material. The carbon material may be either low-crystalline carbon or high-crystalline carbon.

[0064] The separation membrane may be a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., either alone or in a laminate thereof. As another example, the separation membrane may be a conventional porous nonwoven fabric, for example, a nonwoven fabric made of a high-melting point glass fiber, polyethylene terephthalate fiber, etc.

[0065] At least one surface of the separator may include a coating layer of inorganic particles. Alternatively, the separator itself may be made of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound with a binder so that interstitial volume exists between adjacent particles.

[0066] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. Non-limiting examples of the inorganic particles include Pb(Zr,Ti)O3 (PZT), Pb 1-x Lax Zr 1-y Ti y O3(PLZT), PB(Mg3Nb 2 / 3 )O3PbTiO3(PMN-PT), BaTiO3, hafnia (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO, and Y2O3.

[0067] The electrolyte is A + B - The salt may have the following structure: + Li + , Na + , K. + These include alkali metal cations such as B and B - is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C -, CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , and (CF3CF2SO2)2N - The compound contains one or more anions selected from the group consisting of:

[0068] The electrolyte can also be dissolved in an organic solvent, such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), gamma-butyrolactone, or a mixture thereof.

[0069] The first electrode tab 11 and the second electrode tab 12 may be electrically connected to the current collecting plate 30 (P), respectively. The first electrode tab 11 and the second electrode tab 12 may be coupled to the first current collecting plate 30 and the second current collecting plate (P), respectively, by welding or the like, in a state where they are not bent in the radial direction as shown in FIG. 1 or in a state where they are bent in the radial direction (not shown).

[0070] The battery can 20 is a substantially cylindrical container having an opening on one side and is made of a conductive metal material. For example, the battery can 20 may be made of steel or aluminum, but the present invention is not limited thereto. The side and bottom of the battery can 20 (the bottom side in FIG. 1 ) opposite the opening are integrally formed. That is, the battery can 20 generally has an open top end and a closed bottom end. For example, the side walls and bottom of the battery can 51 may be formed by pressing and drawing a metal sheet.

[0071] The bottom surface of the battery can 20 may have a substantially flat shape.

[0072] A hole may be formed in the center of the bottom surface of the battery can 20, and the cell terminal 50 may be coupled to the hole via an insulating gasket (G2). As a result, the battery can 20 itself may constitute a first electrode terminal (T1), and the cell terminal 50 may constitute a second electrode terminal (T2).

[0073] The battery can 20 accommodates the electrode assembly 10 coupled with the current collector plate 30(P) through an opening formed on one side in the height direction (the upper part in FIG. 1 ). The battery can 20 may also accommodate an electrolyte through the opening.

[0074] When the electrode assembly 10 is housed in the battery can 20, the second current collector (P) is electrically connected to the cell terminal 50 by welding or the like. To prevent the second current collector (P) of the electrode assembly 10 from coming into contact with the bottom of the battery can 20, which constitutes the first electrode terminal (T1), and causing a short circuit, an insulator (S) may be interposed between the bottom of the battery can 20 and the second current collector (P).

[0075] The battery can 20 may have a beading portion 21 formed at an upper end thereof. The beading portion 21 may be processed in a state where the electrode assembly 10 is housed inside the battery can 20.

[0076] The beading portion 21 is formed by pressing the outer periphery of the battery can 20 to a predetermined depth, and the inner diameter of the battery can 20 in the area where the beading portion 21 is formed is smaller than the diameter of the electrode assembly 10.

[0077] The edge of the first current collector plate 30 connected to the first electrode tab 11 of the electrode assembly 10 may be placed on the beading portion 21 .

[0078] Referring to FIG. 2 , the first current collector plate 30 includes a loop-shaped portion 31, at least one tab coupling portion 32 extending radially outward from the loop-shaped portion 31 and coupled to the first electrode tab 11, and at least one can coupling portion 33 extending radially outward from the loop-shaped portion 31 and coupled to the inner surface of the battery can 20.

[0079] The number of the tab connecting portion 32 and the can connecting portion 33 may be one or more, and preferably three to six of them may be arranged at equal intervals along the circumferential direction.

[0080] The loop-shaped portion 31 and the at least one tab coupling portion 32 may be disposed on the upper portion of the electrode assembly 10 and may be located lower than the beading portion 21 formed on the battery can 20. These may be provided in a form that is in close contact with the first electrode tab 11 provided on the upper portion of the electrode assembly 10.

[0081] The loop-shaped portion 31 may be provided at the center of the first current collector plate 30. Therefore, the loop-shaped portion 31 may also be referred to as a center portion. The center portion 31 includes a current collector plate hole (H2) formed at a position corresponding to a winding hole (H1) formed at the center of the electrode assembly 10. Thus, when the first current collector plate 30 is coupled to the first electrode tab 11, the hollow portion of the electrode assembly 10, i.e., the winding hole (H1), may be exposed to the upper side through the current collector plate hole (H2). The winding hole (H1) and the current collector plate hole (H2), which are connected to each other, may function as a passage for inserting a welding rod or irradiating a laser beam for welding between the cell terminal 50 and the second current collector plate (P), and may also be used as a passage for the inflow of electrolyte.

[0082] The at least one tab connecting portion 32 may be welded (W) to the first electrode tab 11. In order to ensure impregnation of the electrolyte, a liquid injection hole (H3) may be formed in the tab connecting portion 32.

[0083] The at least one can coupling portion 33 may extend from an end of the center portion 31 toward a side wall of the battery can 20. The can coupling portion 33 may be coupled to a beading portion 21 on the inner surface of the battery can 20. As shown in FIG. 1 , the upper surface of the beading portion 21 may extend in a direction substantially aligned with the lower surface of the battery can 20, i.e., in a direction substantially perpendicular to the side wall of the battery can 20, and the can coupling portion 33 may also extend in the same direction so that the can coupling portion 33 comes into contact with the beading portion 21.

[0084] Referring to FIG. 2, the can coupling part 33 includes a contact part 33a coupled to the beading part 21 of the battery can 20, and a coupling part 33b connecting the center part 31 and the contact part 33a.

[0085] The connecting portion 33b may be configured to have at least one bending portion (B) between the center portion 31 and the contact portion 33a, where the extending direction of the connecting portion 33b is changed, so that the connecting portion 33b can be contracted and expanded within a certain range.

[0086] In this manner, with the electrode assembly 10 housed in the battery can 20 and the current collector plate 30 (P) connected to each electrode terminal (T1, T2), an electrolyte can be poured into the battery can 20 through the open top of the battery can 20. According to this embodiment, the hollow portion of the electrode assembly 10 is exposed to the top through the current collector plate hole (H2) of the first current collector plate 30. Therefore, when pouring the electrolyte, it is inevitable that the core portion of the electrode assembly 10 may be deformed by being impacted by the considerable momentum of the falling electrolyte.

[0087] For this reason, the present invention provides an inlet structure 70 for an electrolyte injection device that can reduce the momentum of the electrolyte injected into the hollow portion of the electrode assembly 10. The inlet structure 70 for the electrolyte injection device can be fitted with its edge placed on the beading portion 21, placed on the upper end of the side wall of the battery can 20, or fitted to the inner circumferential surface of the side wall of the battery can 20, and electrolyte can be injected in this state. The structure of the inlet structure 70 for the electrolyte injection device will be described later.

[0088] The beading portion 21 provides a support surface on which the can cover 40 can be seated. The contact portion 33a of the current collector plate 30 may be placed on the upper surface of the beading portion 21, and the edge of the can cover 40 may be placed on the upper surface of the beading portion 21.

[0089] The battery can 20 further includes a crimped portion 22 formed above the beading portion 21 .

[0090] The crimped portion 22 is formed on the upper portion of the beading portion 21. The crimped portion 22 has an extended and bent shape so as to surround the edge of the can cover 40 placed on the upper portion of the beading portion 21. The shape of the crimped portion 22 allows the can cover 40 to be fixed onto the beading portion 21.

[0091] The can cover 40 covers the opening formed on one side of the battery can 20. The can cover 40 may be fixed by a crimp portion 22 formed on the upper end of the battery can 20. In this case, a seal gasket (G1) may be interposed between the battery can 20 and the can cover 40 to improve fixing strength and sealing of the battery can 20. Since both electrode terminals (T1, T2) of the cylindrical secondary battery described in the embodiment are disposed at the bottom, the can cover 40 does not need to function as a current path. In this regard, the seal gasket (G1) may be interposed between the can cover 40 and the battery can 20 where they are mated.

[0092] The can cover 40 may further include a vent groove 41 for venting the electrolyte.

[0093] Preferably, the cylindrical battery cell may be, for example, a cylindrical battery cell having a form factor ratio (defined as the diameter of a cylindrical battery cell divided by its height, i.e., the ratio of the diameter (Φ) to the height (H)) greater than approximately 0.4.

[0094] Here, the form factor refers to a value indicating the diameter and height of a cylindrical battery cell. Cylindrical battery cells according to an embodiment of the present invention may be, for example, 46110 cells, 48750 cells, 48110 cells, 48800 cells, or 46800 cells. In the numerical value indicating the form factor, the first s indicates the diameter of the cell, the next two digits indicate the height of the cell, and the final 0 indicates that the cross section of the cell is circular.

[0095] A battery cell according to one embodiment of the present invention may be a cylindrical battery cell that is a substantially cylindrical cell, with a diameter of approximately 46 mm, a height of approximately 110 mm, and a form factor ratio of 0.418.

[0096] Another embodiment of the battery cell may be a cylindrical battery cell having a substantially cylindrical shape with a diameter of approximately 48 mm, a height of approximately 75 mm, and a form factor ratio of 0.640.

[0097] In yet another embodiment, the battery cell may be a cylindrical battery cell having a substantially cylindrical shape with a diameter of approximately 48 mm, a height of approximately 110 mm, and a form factor ratio of 0.418.

[0098] In yet another embodiment, the battery cell may be a cylindrical battery cell having a substantially cylindrical shape with a diameter of approximately 48 mm, a height of approximately 80 mm, and a form factor ratio of 0.600.

[0099] In yet another embodiment, the battery cell may be a cylindrical battery cell having a substantially cylindrical shape with a diameter of approximately 46 mm, a height of approximately 80 mm, and a form factor ratio of 0.575.

[0100] Conventionally, battery cells with a form factor ratio of approximately 0.4 or less have been used. For example, 18650 cells, 21700 cells, etc. have been used. 18650 cells have a diameter of approximately 18 mm, a height of approximately 65 mm, and a form factor ratio of 0.277. 21700 cells have a diameter of approximately 21 mm, a height of approximately 70 mm, and a form factor ratio of 0.300.

[0101] [Electrolyte injection machine inlet structure] An embodiment of an inlet structure of an electrolyte injection device according to the present invention will be described below with reference to Figures 3 to 10. The inlet structure 70 of the injection device is installed on an injection device that injects electrolyte into a battery cell. The electrolyte is injected into the battery cell through the inlet structure 70 of the injection device.

[0102] The inlet structure of the liquid injection machine includes a closed-loop outer ring 71 that defines an interior region. The outer ring 71 may be, for example, circular. The electrolyte supplied from the liquid injection machine is supplied to the battery cell through an interior region 72 of the outer ring 71.

[0103] The cross section of the inner region 72 of the outer ring 71 is smaller than the cross section of the upper opening of the battery cell.

[0104] A momentum reducer 73 is provided in the center of the internal region 72. The momentum reducer 73 is disposed at a position that covers the winding hole (H1) of the secondary battery, i.e., the hollow portion, when the inlet structure 70 of the liquid injection device is placed on top of the battery can 20.

[0105] The momentum reducer 73 obstructs or blocks the flow of electrolyte solution injected into the center of the inner region 72 among the electrolyte solution supplied through the inner region 72. As a result, the electrolyte solution passing through the center of the inner region 72 does not directly drop into the winding hole (H1) located below the momentum reducer 73, i.e., the hollow portion, but instead bypasses and is supplied through the space between the momentum reducer 73 and the outer ring 71 in the inner region 72. In other words, the momentum reducer 73 reduces the momentum and kinetic energy of the electrolyte solution flowing through the center of the inner region 72.

[0106] The first current collector plate 30 fixed to the top of the electrode assembly 10 covers almost all of the area except for the hollow portion of the electrode assembly 10, and the first electrode tabs 11 are bent radially and overlap each other, so even if the electrolyte is dropped and supplied directly to this area, there is no risk of deformation or damage to the electrode assembly 10.

[0107] The inlet structure 70 of the injection machine includes one or more connecting members 76 extending from the outer ring 71 toward the center of the outer ring 71 and connected to the momentum reducer 73 to support the momentum reducer 73.

[0108] The connecting members 76 may extend radially from the center of the outer ring 71. Figures 3, 4, 6, 7, and 8 illustrate a structure in which four connecting members 76 are arranged at 90-degree intervals. Figure 5 illustrates a structure in which eight connecting members 76 are arranged at 45-degree intervals. The number of connecting members 76 is not limited to the illustrated embodiment.

[0109] The momentum reducer 73 may be configured to completely shield the center of the internal region, as in the embodiment shown in Figures 3 to 5. With this structure, the electrolyte passes through the inlet structure 70 of the injection device and is supplied to the battery can 20 while completely bypassing the center of the internal region, thereby reliably preventing damage to the hollow portion of the electrode assembly 10.

[0110] However, the momentum reducing portion 73 does not necessarily have to be completely closed. The momentum reducing portion 73 is a form that reduces the momentum or kinetic energy of the electrolyte supplied to the hollow portion of the electrode assembly 10, and may have one or more through holes 74.

[0111] In this case, the number of through holes 74 may be one or more, and the size of each through hole 74 may be smaller than the size of the hollow portion (H1) of the electrode assembly 10. Fig. 6 illustrates a structure in which one circular through hole 74 smaller than the hollow portion of the electrode assembly 10 is formed in the center of the momentum reducer 73. In this case, the falling speed of the electrolyte passing through the through hole 74 of the momentum reducer 73 and descending is significantly reduced due to the viscosity of the inner circumferential surface of the through hole 74, and the electrolyte is supplied to the hollow portion (H1) of the electrode assembly 10.

[0112] 7 and 8, the momentum reducer 73 may have a plurality of through holes 74, and the plurality of through holes 74 may be defined by a lattice member 75. The connecting member 76 has a certain thickness to block the flow of electrolyte and support the momentum reducer 73, which bears a large load. On the other hand, the lattice member 75 may be thinner than the connecting member 76 to ensure a larger contact area with the electrolyte flowing through the through holes 74.

[0113] 7, the grid member 75 may include one first grid member 751 extending in a first direction and one second grid member 752 extending in a second direction intersecting the first direction. This allows the grid member 75 to define four through holes 74. Although FIG. 7 illustrates a structure in which the first grid member 751 and the second grid member 752 intersect at right angles, the intersecting pattern is not necessarily limited thereto. For example, the grid member 75 may further include a third grid member 75 extending in a third direction intersecting both the first and second directions, and these may intersect with each other at 60-degree intervals.

[0114] 8, the lattice member 75 may include a plurality of first lattice members 751 extending in a first direction and a plurality of second lattice members 752 extending in a second direction intersecting the first direction, thereby defining a plurality of through holes 74 by the lattice member 75.

[0115] The cross-sectional area of ​​each of the through holes 74 determined by these grid members 75 may be smaller than the cross-sectional area of ​​the hollow portion of the electrode assembly 10. When the momentum reducer 73 is provided with these through holes 74, the electrolyte supplied through the center of the inlet structure 70 of the injection device passes through the momentum reducer 73, but its momentum is significantly reduced before passing through and being supplied to the hollow portion of the electrode assembly 10, thereby preventing damage to the core portion of the electrode assembly 10.

[0116] 9, the grid member 75 may constitute the momentum reducer 73 and the connecting member 76. Referring to FIG. 9, the momentum reducer 73 may be defined as a portion where a first grid member 751 and a second grid member 752 intersect to define a through-hole 74 having a cross section smaller than the hollow portion of the electrode assembly 10, and the connecting member 76 may be defined as a portion connecting the momentum reducer 73 and the outer ring 71.

[0117] Furthermore, as shown in FIG. 10, the grid member 75 may be formed not only in the momentum reducer 73 but also over the entire inner region of the outer ring 71 around the momentum reducer 73.

[0118] Since the lattice member 75 is disposed throughout the entire interior region, the through holes 74 may also be disposed throughout the entire interior region. Thus, even if a large amount of electrolyte is introduced at once by supplying an electrolyte to a secondary battery with a larger specification than conventional batteries, the electrolyte passes through the through holes 74 disposed throughout the entire interior region and is supplied to the electrode assembly 10 with its momentum significantly reduced due to the viscosity of the electrolyte and the inner walls of the through holes 74, thereby minimizing damage to the electrode assembly 10.

[0119] The outer ring 71, momentum reducer 73, and connecting member 76 can be integrally molded by injection molding or the like to form a single component.

[0120] The momentum reducer 73 and the connecting member 76 have sufficient rigidity to withstand the impact of collision with the flowing electrolyte, and therefore the outer ring 71 that supports them can be made integrally with the connecting member 76 and the momentum reducer 73 using the same material. These materials may be lighter than the cover ring 77, which will be described later.

[0121] Meanwhile, as shown in FIG. 3, a cover ring 77 may be further provided on the outer periphery of the outer ring 71 to surround the outer ring 71 and to be coupled to the outer ring 71 .

[0122] The cover ring 77 may be made of a different material from that of the outer ring 71 .

[0123] The cover ring 77 is a portion that engages with the battery can 20 and can be made of a material that is more flexible than the outer ring 71. That is, the cover ring 77 may be made of a material that is softer than the outer ring 71.

[0124] The outer ring 71, the momentum reducing portion 73, the connecting member 76, and the cover ring 77 include a polymer material that is insoluble in the electrolyte and does not chemically react with it.

[0125] It should be understood that the above-described embodiments are illustrative in all respects and are not limiting, and the scope of the present invention is defined by the following claims rather than the above detailed description. All modifications and variations within the meaning and scope of the following claims, as well as equivalent concepts, should be construed as being included within the scope of the present invention.

[0126] Although the present invention has been described above with reference to illustrative drawings, the present invention is not limited to the embodiments and drawings disclosed in this specification, and various modifications may be made by those skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention are not explicitly described and explained while describing the embodiments of the present invention, it is natural that the effects that can be predicted by the configuration should also be recognized. [Explanation of symbols]

[0127] 1 Cylindrical secondary battery 10 Electrode assembly 11 First electrode tab 12 Second electrode tab H1 Winding hole (hollow part) 20 Battery can 21 Beading section 22 Crimp section 30 Current collector plate (first current collector plate) H2 Current collector plate hole 31 Loop-shaped part (center) 32 Tab joint H3 liquid injection hole 33 Can joint 33a Contact part 33b Connection part 40 Can Covers 41 Vent groove G1 seal gasket 50 Cell terminal G2 Insulation Gasket T1 1st electrode terminal T2 2nd electrode terminal P Current collector plate (second current collector plate) S insulator W welded section 70 Inlet structure of the liquid injection machine 71 Outering 72 Internal area 73 Momentum reduction part 74 Through Hole 75 Lattice Members 751 First lattice member 752 Second lattice member 76 Connecting member 77 Covering X: Length direction of electrode plate (circumferential direction) Y Width direction (axial direction) of electrode plate Z radial direction

Claims

1. An inlet structure (70) of a liquid injection device for injecting an electrolyte into a battery cell, a closed loop outer ring (71) defining an inner region; A momentum reducing portion (73) disposed in the center of the internal region so as to collide with the electrolyte injected through the internal region and injected into the center of the internal region; and one or more connecting members (76) extending from the outer ring (71) toward the central portion of the outer ring (71) and connecting to the momentum reducer portion (73); Including, the momentum reduction portion is spaced apart from the outer ring, and a space is formed between the momentum reduction portion and the outer ring through which the electrolyte that bypasses the central portion of the internal region can pass by the momentum reduction portion. Inlet structure of the liquid injection machine.

2. An inlet structure (70) of a liquid injection machine that injects electrolyte into a battery cell, a closed loop outer ring (71) defining an inner region; A momentum reducing portion (73) disposed at the center of the inner region, spaced apart from the outer ring (71), so as to collide with the electrolyte injected through the inner region and injected into the center of the inner region; and one or more connecting members (76) extending from the outer ring (71) toward the central portion of the outer ring (71) and connecting to the momentum reducer portion (73); Including, The connecting member (76) extends radially from the central portion of the outer ring (71). Inlet structure of the liquid injection machine.

3. The momentum reducing portion (73) is configured to shield the center of the internal region. The inlet structure of the liquid injection machine according to claim 1.

4. An inlet structure (70) of an injection machine that injects electrolyte into a battery cell, a closed loop outer ring (71) defining an inner region; A momentum reducing portion (73) disposed at the center of the inner region, spaced apart from the outer ring (71), so as to collide with the electrolyte injected through the inner region and injected into the center of the inner region; and one or more connecting members (76) extending from the outer ring (71) toward the central portion of the outer ring (71) and connecting to the momentum reducer portion (73); Including, The momentum reducing portion (73) is provided with one or more through holes (74) having a cross section smaller than the cross section of the hollow portion of the electrode assembly of the battery cell in which the inlet structure of the liquid injection device is used. Inlet structure of the liquid injection machine.

5. The through holes (74) are provided in plurality, The plurality of through holes (74) are defined by a lattice member (75). The inlet structure of the liquid injection machine according to claim 4.

6. The grid member (75) includes one or more first grid members (751) extending in a first direction and one or more second grid members (752) extending in a second direction intersecting the first direction. The inlet structure of the liquid injection machine according to claim 5.

7. The grid member (75) constitutes the momentum reducer (73) and also constitutes the connecting member (76). The inlet structure of a liquid injection machine according to claim 6.

8. The grid member (75) is formed not only in the momentum reduction portion (73) but also over the entire inner region of the outer ring around the momentum reduction portion (73). The inlet structure of a liquid injection machine according to claim 6.

9. The outer ring (71), the momentum reducer (73) and the connecting member (76) constitute an integral part. The inlet structure of the liquid injection machine according to claim 1.

10. An inlet structure (70) of a liquid injection machine that injects electrolyte into a battery cell, a closed loop outer ring (71) defining an inner region; A momentum reducing portion (73) disposed at the center of the inner region, spaced apart from the outer ring (71), so as to collide with the electrolyte injected through the inner region and injected into the center of the inner region; and one or more connecting members (76) extending from the outer ring (71) toward the central portion of the outer ring (71) and connecting to the momentum reducer portion (73); Including, A cover ring (77) is provided on the outer periphery of the outer ring (71), surrounding the outer ring (71) and being coupled to the outer ring (71). Inlet structure of the liquid injection machine.

11. The outer ring (71), the momentum reducing portion (73), the connecting member (76), and the covering ring (77) contain a polymer material that is insoluble in and chemically unreactive with the electrolyte, and the covering ring (77) is softer than the outer ring (71). The inlet structure of the liquid injection machine according to claim 10.

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