Battery cell, and battery pack and vehicle including the same

Abstract

The battery cell of the present invention comprises an electrode assembly in which a first electrode and a second electrode and a separator interposed between them are wound with respect to a winding axis, and a non-solid portion exposed to the outside of the separator is formed at the ends of the first electrode and the second electrode, respectively; a can configured to accommodate the electrode assembly through an open end formed on one side; and a lead covering the open end, wherein the lead has a non-solid portion coupling portion configured such that at least a portion of its inner surface is electrically connected to the first electrode, and the first non-solid portion formed at the end of the first electrode may have an inner non-solid portion configured to be connected to the non-solid portion coupling portion and an outer non-solid portion located radially outside the inner non-solid portion.

Description

Technology Field

[0001] The present invention relates to a battery cell, a battery pack including the battery cell, and an automobile. Background Technology

[0003] Secondary batteries, which possess electrical characteristics such as high energy density and high applicability across product categories, are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) powered by electric sources.

[0004] These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency, not only for the primary advantage of being able to drastically reduce the use of fossil fuels, but also because they do not generate any by-products from the use of energy.

[0005] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. When a high output voltage is required, multiple battery cells are connected in series to form a battery module or battery pack. Additionally, to increase charge / discharge capacity, multiple battery cells are connected in parallel to form a battery module or battery pack. Therefore, the number of battery cells included in the battery module or pack can be varied depending on the required output voltage or charge / discharge capacity.

[0006] There is increasing demand for metal can-type cells as battery cells for automotive battery packs. Metal cans can be prismatic or cylindrical; cylindrical battery cells feature a structure that accommodates a jelly-roll type electrode assembly inside a cylindrical can, offering the advantage of being more robust against shock and temperature than pouch-type battery cells.

[0007] In the case of a cylindrical battery cell, an insulating separator is interposed between the positive and negative electrodes, and a jellyroll-shaped electrode assembly can be formed by winding the separator. After the winding process, the non-solid portions of the positive and negative electrode plates can be connected to external electrode terminals through a current collector plate or the like. At this time, to improve the welding characteristics of the non-solid portions and the current collector plate, the non-solid portions can be folded as flat as possible.

[0008] However, when a folded surface area is formed across the entire upper surface of the electrode assembly due to the folding of the uncoated portion, when a thermal event occurs within the battery, the entire electrode assembly corresponding to the folded surface area is ejected from the battery as a single mass. In this case, there may be difficulties in smoothly ejecting the electrode assembly due to friction with the side wall of the can. When the electrode assembly remains inside the can, it becomes a problem because heat may be transferred to adjacent battery cells due to the high thermal capacity of the electrode assembly.

[0009] Therefore, there is a need to develop a battery cell structure that facilitates the electrode assembly from escaping to the outside of the battery when a thermal event occurs within the battery. The problem to be solved

[0011] The present invention was conceived against the background of the prior art described above, and aims to provide a battery cell in which the electrode assembly can easily escape to the outside of the battery when a thermal event occurs within the battery.

[0012] Another technical objective of the present invention is to provide a battery pack including a battery cell of an improved structure, and a vehicle including the battery pack.

[0013] The technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description of the invention below. means of solving the problem

[0015] To solve the above problem, the battery cell of the present invention comprises an electrode assembly in which a first electrode and a second electrode and a separator interposed between them are wound with respect to a winding axis, and a non-removable portion exposed to the outside of the separator is formed at the ends of the first electrode and the second electrode, respectively, and a can configured to accommodate the electrode assembly through an open end formed on one side, wherein the first non-removable portion formed at the end of the first electrode may have an inner non-removable portion configured to be electrically connected to the can and an outer non-removable portion located radially outside the inner non-removable portion and configured not to be coupled to the inner non-removable portion.

[0016] The battery cell of the present invention further comprises a lead covering the open end, the lead having a non-removable portion coupling portion configured such that at least a portion of the inner surface is electrically connected to a first electrode, and the inner non-removable portion may be configured to be connected to the non-removable portion coupling portion.

[0017] The above outer non-removable portion may be positioned radially outward from a position corresponding in the vertical direction to the above non-removable portion joining portion.

[0018] The inner bare portion is folded inward in the radial direction to form a folded surface area while overlapping each other, and at least a portion of the folded surface area may be in contact with the bare portion joint portion.

[0019] The above-mentioned non-recessed joint may be formed by being recessed in the direction toward the electrode assembly.

[0020] The device further includes a plug configured to seal an injection port formed in the center of the above-mentioned lead, and the lead further comprises a body portion on which the plug is seated and an edge portion located at the edge of the lead, and the non-removable portion coupling portion may be located between the body portion and the edge portion with respect to the radial direction.

[0021] A vent portion may be further provided between the edge portion and the non-reinforced portion joining portion, and the outer non-reinforced portion may be located radially outward with respect to the vent portion, and the inner non-reinforced portion may be located radially inward with respect to the vent portion.

[0022] When a thermal event occurs within the battery cell, the inner undisturbed portion may be configured to be discharged to the outside of the battery cell.

[0023] The above outer bare portion may be configured so as not to be combined with the above inner bare portion.

[0024] The above outer blank portion may be configured to be electrically coupled with the can.

[0025] The above lead may be configured to be joined to the open end of the can by welding.

[0026] In addition, the present invention can provide a battery pack characterized by including a battery cell according to the present invention.

[0027] In addition, the present invention can provide an automobile characterized by including a battery cell according to the present invention. Effects of the invention

[0029] According to one embodiment of the present invention, a battery cell can be provided in which an electrode assembly can easily escape to the outside of the battery when a thermal event occurs within the battery.

[0030] In addition, according to another aspect of the present invention, events resulting from thermal runaway in a vehicle comprising a plurality of battery cells, such as fire or explosion, can be prevented or delayed.

[0031] In addition to the above, the present invention may have various other effects, which are described in each embodiment, or effects that can be easily inferred by those skilled in the art, etc., will be omitted. Brief explanation of the drawing

[0033] 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 such drawings. FIG. 1 is a perspective view showing the appearance of a battery cell according to one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along A-A' of the battery cell of FIG. 1 according to one embodiment of the present invention. FIG. 3 is a cross-sectional view of the battery cell of FIG. 1 cut along A-A' according to another embodiment of the present invention. FIG. 4 is a cross-sectional view of an electrode assembly of a battery cell according to one embodiment of the present invention. FIG. 5 is a separated cross-sectional view of an electrode assembly and a lead constituting a battery cell according to one embodiment of the present invention. FIG. 6 is an exploded perspective view of a battery cell according to one embodiment of the present invention. FIG. 7 is a diagram showing a thermal event occurring in a battery cell according to one embodiment of the present invention. FIG. 8 is a drawing illustrating the unfolded state of the first electrode of a battery cell according to one embodiment of the present invention. FIG. 9 is a drawing illustrating the unfolded state of the first electrode of a battery cell according to another embodiment of the present invention. FIG. 10 is a cross-sectional view of a battery cell according to another embodiment of the present invention. FIG. 11 is an enlarged view of part B of FIG. 10 according to another embodiment of the present invention. FIG. 12 is a cross-sectional view of a battery cell according to another embodiment of the present invention. FIG. 13 is an enlarged view of part C of FIG. 12 according to another embodiment of the present invention. FIG. 14 is a drawing for explaining a battery pack according to one embodiment of the present invention. FIG. 15 is a drawing for explaining a vehicle including the battery pack of FIG. 14. Specific details for implementing the invention

[0034] Hereinafter, preferred embodiments of the present invention will be described in detail 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, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0035] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0036] In addition, the present invention includes various embodiments. For each embodiment, redundant descriptions of substantially identical or similar configurations are omitted, and the focus is on the differences.

[0037] 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.

[0038] 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.

[0039] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0040] In the following, the statement 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.

[0041] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0042] Singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be omitted or additional components or steps may be included.

[0043] 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.

[0044] For convenience of explanation, in this specification, the direction following the longitudinal direction of the winding axis of an electrode assembly wound in a jelly roll shape is referred to as the axial direction (Y). The direction surrounding the winding axis is referred to as the circumferential direction or periphery direction (X). The direction approaching the winding axis or moving away from the winding axis is referred to as the radial direction or radial direction (Z). In particular, the direction approaching the winding axis is referred to as the centripetal direction, and the direction moving away from the winding axis is referred to as the centrifugal direction.

[0045] FIG. 1 is a perspective view showing the external appearance of a battery cell according to one embodiment of the present invention. FIG. 2 is a cross-sectional view of the battery cell of FIG. 1 taken along A-A' according to one embodiment of the present invention.

[0046] Referring to FIGS. 1 to 3, a battery cell (10) according to one embodiment of the present invention may include an electrode assembly (100) and a can (200).

[0047] Referring to FIG. 2, the electrode assembly (100) may be in the form of a jelly-roll in which the first electrode and the second electrode and the separator interposed between them are wound along a winding axis. For example, the first electrode may be an anode and the second electrode may be a cathode. Here, the first electrode and the second electrode may be formed in a sheet shape. An additional separator may be provided on the outer surface of the electrode assembly (100) for insulation from the can (200). The structure of the electrode assembly (100) is not limited by the embodiment and may have a winding structure well known in the art.

[0048] An uncoated portion exposed to the outside of the separator may be formed at the ends of the first electrode and the second electrode, respectively. The uncoated portion (e.g., first uncoated portion (110), second uncoated portion (120)) may refer to a portion that is not coated with an active material.

[0049] Specifically, the first electrode may be an anode plate and the second electrode may be a cathode plate. An anode active material may be coated on one or both sides of the anode plate, and a first uncoated portion (110) in which the anode active material is not coated may be formed at the end of the anode plate. The first uncoated portion (110) may be exposed to the outside of the separator while forming a plurality of wound turns based on the center of the electrode assembly (100) and may be used as an electrode tab itself. A cathode active material may be coated on one or both sides of the cathode plate, and a second uncoated portion (120) in which the cathode active material is not coated may be formed at the end of the cathode plate. The second uncoated portion (120) may be exposed to the outside of the separator while forming a plurality of wound turns based on the center of the electrode assembly (100) and may be used as an electrode tab itself. That is, the positive plate and the negative plate may each include an uncoated portion (e.g., a first uncoated portion (110), a second uncoated portion (120)) at the long end of the winding direction in which the active material is not coated. Additionally, the first uncoated portion (110) and the second uncoated portion (120) may be configured to face in opposite directions. The first uncoated portion (110) may be housed inside the can (200) so as to be located at one end in the winding axis direction and the second uncoated portion (120) at the other end in the winding axis direction. Here, the positive active material coated on the positive plate and the negative active material coated on the negative plate may be used without limitation as long as they are active materials known in the art.

[0050] In addition, the separator may be a porous polymer film, such as a polyolefin-based polymer like ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, etc., used alone or in a laminated form. As another example, the separator may be a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers, polyethylene terephthalate fibers, etc.

[0051] At least one surface of the separation membrane may include a coating layer of inorganic particles. It is also possible for the separation membrane itself to consist of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure bonded with a binder such that interstitial volume exists between adjacent particles.

[0052] Referring to FIGS. 1 to 3, a can (200) may be configured to accommodate an electrode assembly (100). The can (200) may have an open end formed on one side. The can (200) may be a roughly cylindrical receptacle with an open end formed on one side. The can (200) may accommodate the electrode assembly (100) through the open end formed on one side. For example, the electrode assembly (100) may be accommodated inside the can (200) such that the first non-retaining portion (110) faces the open end. Specifically, the can (200) may include a side wall portion (201), a bottom portion (202) connected to one axial end of the side wall portion (201), and an open end provided at the other axial end of the side wall portion (201). The side wall portion (201) and the bottom portion (202) of the can (200) may be formed integrally. The bottom portion (202) has a roughly flat shape. The side wall portion (201) may be cylindrical, connected to the bottom portion (202), and may extend in the direction of the winding axis. At this time, the side wall portion (201) that is not connected to the bottom portion (202) may be defined as the open end of the can (200). In FIGS. 1 and 2, the bottom portion (202) is shown as being included at the bottom of the can (200), and the open end is shown as being included at the top of the can (200). The open end may be formed in the portion facing the bottom portion (202) of the can (200).

[0053] The side wall portion (201) of the can (200) may be configured to have a cylindrical shape with a constant radius. Preferably, the entire area of ​​the side wall portion (201) of the can (200) may be configured to have a cylindrical shape with a constant radius. The bottom portion (202) of the can (200) forms a closed surface of the can (200), and a through hole is formed in the bottom portion (202), and an electrode terminal (210) can pass through the through hole.

[0054] Conventional cans (200) may further include a beading portion formed at an open end and an adjacent end, and a clamping portion formed on the beading portion; however, the can (200) of the present invention may not have a beading clamping structure formed on the side wall portion (201). That is, the can (200) of the present invention may not have the side wall portion (201) inserted inward. That is, the can (200) of the present invention may be configured to have a constant radius over the entire area of ​​the side wall portion (201).

[0055] According to this structure, by excluding the beading and crimping structure from the cylindrical battery cell (10), various process errors that may occur due to the beading and crimping structure can be prevented. In addition, process simplification can be achieved by omitting processes such as beading and crimping. Furthermore, the phenomenon in which the dead space within the battery increases and the energy density decreases in the direction of the winding axis of the electrode assembly (100) due to the formation of the beading and crimping structure can be prevented. Therefore, the battery cell (10) according to the present invention can increase the internal capacity more than a battery cell using the beading and crimping method with the same external shape. That is, according to the structure of the present invention, the energy density of the battery cell (10) can be improved.

[0056] The can (200) may include a conductive metal material. The material of the can (200) may include a conductive metal, such as aluminum, steel, stainless steel, etc. For example, the bottom portion (202) and the side wall portion (201) may be manufactured by forming a metal sheet, on which nickel is plated on the surface of steel, using a deep drawing process, and then trimming the front end of the side wall portion (201) with a punch while holding it with a blank holder. However, the material and manufacturing method of the can (200) are not limited thereto.

[0057] The can (200) can be electrically connected to at least a portion of the first non-electrode portion (110) of the electrode assembly (100). Accordingly, the can (200) can have a first polarity.

[0058] Specifically, the first uninhibited portion (110) formed at the end of the first electrode may have an inner uninhibited portion (111) and an outer uninhibited portion (112). That is, the first uninhibited portion (110) may be divided into an inner uninhibited portion (111) and an outer uninhibited portion (112) based on the radial direction.

[0059] The inner bare portion (111) may be configured to be electrically connected to the can (200). At least a portion of the inner bare portion (111) may be bent. The inner bare portion (111) may be bent inward in the radial direction. For example, the inner bare portion (111) may be bent one by one during the process of forming the electrode assembly (100). Or, for example, the inner bare portion (111) may be bent all at once after forming the electrode assembly (100). The outer bare portion (112) may be located radially outward of the inner bare portion (111). The outer bare portion (112) may be positioned radially outward from a position corresponding in the vertical direction to the bare portion coupling portion (310).

[0060] The outer thumb portion (112) can be configured so as not to be combined with the inner thumb portion (111). That is, the outer thumb portion (112) and the inner thumb portion (111) can be physically separated.

[0061] When the entire uncoordinated portion constituting the electrode assembly (100) is bent in one direction, the entire electrode assembly (100) can move as a single unit when a thermal event occurs within the battery cell (10). Therefore, due to friction with the side wall portion (201) of the can (200), it may be difficult for the electrode assembly (100) to be discharged smoothly and quickly to the outside of the battery cell (10). If the electrode assembly (100) remains inside the battery cell (10), there was a possibility of heat transfer to an adjacent battery cell (10) due to the high thermal capacity of the electrode assembly (100).

[0062] In contrast, according to the above embodiment of the present invention, the inner non-discharge portion (111) and the outer non-discharge portion (112) can be physically and / or electrically separated so that the electrode assembly (100) portion corresponding to the inner non-discharge portion (111) can be configured to be smoothly and quickly discharged to the outside of the battery cell (10). That is, even if only the electrode assembly (100) portion corresponding to the inner non-discharge portion (111) is discharged smoothly to the outside of the battery cell (10). Therefore, when a thermal event occurs within the battery cell (10), it is possible to prevent the electrode assembly (100) from remaining inside the battery cell (10) without being discharged due to friction with the side wall portion (201) of the can (200). Thus, it is possible to prevent heat transfer to an adjacent battery cell (10).

[0063] Referring to FIG. 2, the battery cell (10) may further include a first current collector (130) configured to be electrically connected to a first electrode. The first current collector (130) may be bonded to a substantially flat surface provided by bending the first uncoated portions (110) exposed at the other end of the winding axis direction of the electrode assembly (100). A method such as resistance welding, ultrasonic welding, or laser welding may be used for bonding.

[0064] According to one embodiment, with reference to FIG. 2, the inner portion (111) of the first portion (110) may be in contact with the first collector (130). The inner portion (111) of the first portion (110) may be configured to be connected to the first collector (130). For example, the inner portion (111) of the first portion (110) may be welded to the first collector (130).

[0065] Meanwhile, the battery cell (10) may further include a second current collector (140) configured to be electrically connected to the second electrode. The second current collector (140) may be bonded to a substantially flat surface provided by bending the second uncoated portions (120) exposed at one end of the winding axis direction of the electrode assembly (100) (e.g., the bottom portion in FIG. 2). A method such as resistance welding, ultrasonic welding, or laser welding may be used for bonding. However, the second current collector (140) may be omitted.

[0066] Additionally, the battery cell (10) may further include an insulator (150). The insulator (150) may be provided between the second current collector (140) and the inner surface of the bottom portion (202) of the can (200). The insulator (150) may prevent contact between the second current collector (140) and the can (200). The insulator (150) may also be interposed between the inner surface of the side wall portion (201) of the can (200) and the electrode assembly (100). That is, the insulator (150) may also be interposed between the second non-removable portion (120) and the can (200). This may be to prevent contact between the second non-removable portion (120), which extends toward the bottom portion (202) of the can (200), and the inner surface of the can (200).

[0067] The can (200) can be electrically connected to the first current collector (130), and the electrode terminal (210) can be electrically connected to the second current collector (140). Accordingly, the can (200) may have a first polarity, and the electrode terminal (210) may have a second polarity. That is, the electrode terminal (210) may refer to an electrode terminal (210) having a second polarity. In particular, the bottom portion (202) of the can (200) and the side wall portion (201) connected thereto may both have a first polarity. Accordingly, both a portion having a first polarity and a portion having a second polarity may be provided on the bottom portion (202) side of the can (200). Then, the busbar connected to the electrode terminal (bottom part (202) of the can (200)) having the first polarity and the busbar connected to the electrode terminal (210) having the second polarity can both be located at one end of the winding axis direction of the can (200). In one example, the electrode terminal having the first polarity may be a negative terminal, and the electrode terminal (210) having the second polarity may be a positive terminal. Of course, the opposite may also be true. Accordingly, the battery cell (10) according to the present invention can simplify the electrical connection structure by allowing both the positive and negative terminals to be connected in one direction when electrically connecting a plurality of battery cells (10). In addition, the battery cell (10) according to the present invention has a structure in which most of the bottom part (202) of the can (200) can be used as the electrode terminal having the first polarity, so it can have the advantage of securing a sufficient area for welding components for electrical connection.

[0068] A battery cell (10) according to one embodiment of the present invention may be, for example, a cylindrical secondary battery having a form factor ratio (ratio of height to diameter) greater than approximately 0.4. Preferably, the diameter of the battery cell (10) may be 40 mm to 50 mm, and the height may be 60 mm to 130 mm. The form factor of the battery cell (10) may be, for example, 46110, 4875, 48110, 4880, or 4680.

[0069] However, the shape of the battery cell (10) according to the present invention is not limited by the above and can be applied to batteries of other shapes. For example, it can be applied to prismatic batteries.

[0070] FIG. 3 is a cross-sectional view of the battery cell of FIG. 1 cut along A-A' according to another embodiment of the present invention.

[0071] Referring to FIGS. 1 to 3, a battery cell (10) according to one embodiment of the present invention may further include a lead (300).

[0072] The lid (300) may be configured to cover an open end formed on one side of the can (200). The lid (300) may be configured to have, for example, a roughly plate shape. The lid (300) may be coupled to the open end of the can (200). For example, as shown in FIG. 2, the lid (300) may be seated on the upper edge of the open end of the can (200). Or, for example, the lid (300) may be in contact with the inner surface of the upper edge of the open end of the can (200).

[0073] The lead (300) can be configured to be joined to the open end of the can (200) by welding. The contact point between the open end of the can (200) and the lead (300) can be joined. For example, the lead (300) can be joined to the can (200) using butt welding. Thus, the battery cell (10) can have a larger internal capacity in the same external shape than a battery cell (10) using beading and crimping methods. Thus, the energy density of the battery cell (10) can be increased. However, the can (200) and the lead (300) can be joined by other joining methods other than welding, and the joining method is not limited to this. By joining the can (200) and the lead (300), the battery cell (10) can be sealed.

[0074] The lead (300) may include a metal material. Therefore, the lead (300) may have conductivity. For example, the lead (300) may include an aluminum material. The lead (300) may be electrically connected to the can (200). Meanwhile, since the can (200) also includes a metal that has conductivity, the lead (300) combined with the can (200) may be configured to have the same polarity as the can (200). For example, the lead (300) may be configured to have a first polarity.

[0075] The lead (300) may be provided with a non-reinforced coupling portion (310) configured to be electrically connected to the first electrode. That is, the non-reinforced coupling portion (310) of the lead (300) may be in direct contact with at least a portion of the first non-reinforced portion (110) of the first electrode. The bottom surface of the non-reinforced coupling portion (310) (the surface facing the electrode assembly (100)) may be coupled face-to-face with the electrode assembly (100). The bottom surface of the non-reinforced coupling portion (310) may be coupled with the first non-reinforced portion (110) of the electrode assembly (100). For example, the non-reinforced coupling portion (310) of the lead (300) may be joined to a substantially flat surface provided by bending the first non-reinforced portions (110) exposed at one end in the winding axis direction of the electrode assembly (100). Methods such as resistance welding, ultrasonic welding, or laser welding may be used for joining. For example, the non-removable joint portion (310) may be a ring shape having a constant diameter in the radial direction with respect to the winding axis of the electrode assembly (100).

[0076] According to the above embodiment of the present invention, the first non-removable portion (110) can be directly connected to the lead (300). That is, the lead (300) according to the present invention can be coupled to the can (200) to cover the open end of the can (200), and at the same time, electrically connected to the electrode assembly (100). Accordingly, since the first non-removable portion (110) is electrically connected to the lead (300), the current collector (the first current collector (130) of FIG. 2) can be omitted. That is, the first current collector configured to be electrically connected to the first electrode is omitted, and the lead (300) can perform the role of the first current collector. In other words, the lead (300) according to the present invention can be provided as a so-called integrated lead (300) that can also perform the function of a current collector plate.

[0077] Accordingly, the internal space of the battery cell (10) occupied by the first current collector can be omitted. Therefore, the total height of the electrode assembly (100) can be increased, and the energy density of the battery cell (10) can be improved. In addition, since the first current collector is omitted, the transportation process or welding process of the first current collector can be omitted, thereby improving productivity. For convenience of explanation, the following description will be based on the assumption that the first non-transferable portion (110) is directly connected to the lead (300). However, it is of course possible to apply an embodiment in which the first non-transferable portion (110) is directly connected to the first current collector (130) as shown in FIG. 2.

[0079] FIG. 4 is a cross-sectional view of an electrode assembly of a battery cell according to an embodiment of the present invention. FIG. 5 is a separated cross-sectional view of an electrode assembly and a lead constituting a battery cell according to an embodiment of the present invention. FIG. 6 is a separated perspective view of a battery cell according to an embodiment of the present invention. FIG. 7 is a drawing showing a thermal event occurring in a battery cell according to an embodiment of the present invention.

[0080] The inner bare portion (111) may be configured to be connected to the bare portion connecting portion (310) of the lead (300). For example, the inner bare portion (111) may be configured to be welded to the bare portion connecting portion (310). That is, the inner bare portion (111) may refer to a first bare portion (110) that is weldable to the bare portion connecting portion (310).

[0081] At least a portion of the inner bare portion (111) may be folded. The inner bare portion (111) may be folded inward in the radial direction. The inner bare portion (111) folded inward in the radial direction may overlap to form a folded surface area (F). That is, the inner bare portion (111) may be folded and flattened. The folded surface area (F) may refer to the portion where the folded inner bare portion (111) overlaps with a sufficient amount of overlap. The folded surface area (F) may be provided as a plane substantially perpendicular to the winding axis direction. At this time, the folded surface area (F) may come into contact with the bare portion joining portion (310) of the lead (300). For example, the folded surface area (F) may be positioned at a location corresponding in the vertical direction to the bare portion joining portion (310) and further inward in the radial direction. For example, the folded surface area (F) can be positioned at a location corresponding in a vertical direction to the unwound joint part (310).

[0082] The outer bare portion (112) may be positioned radially outward from a position corresponding in a vertical direction to the bare portion connecting portion (310). For example, referring to FIG. 5, the bare portion connecting portion (310) may be located in an area corresponding in a vertical direction to the folded surface area (F) of the inner bare portion (111). Thus, the bare portion connecting portion (310) may be located radially inward from the outer bare portion (112).

[0083] The outer bare portion (112) may be configured not to be joined with the inner bare portion (111). That is, the outer bare portion (112) may not be folded inward in a radial direction together with the inner bare portion (111). Unlike the inner bare portion (111), the outer bare portion (112) may not be welded to the bare portion joining portion (310).

[0084] According to one embodiment, the outer bare portion (112) may be configured to be cut through a notching process. That is, the outer bare portion (112) may be cut and formed into a short length so as not to come into contact with the inner bare portion (111) and / or the lead (300).

[0085] Referring to FIGS. 4 to 7, the electrode assembly (100) may be divided into a first region (S1) and a second region (S2). The first region (S1) may be defined as a region located radially inward from the first electrode composed of an inner bare portion (111) within the electrode assembly (100). Additionally, the second region (S2) may be defined as a region located radially outward from the first region (S1), where the first electrode composed of an outer bare portion (112) is located. The first region (S1) may be a part of the electrode assembly (100) corresponding to the inner bare portion (111). The first region (S1) may move integrally as a single mass by means of the inner bare portion (111) which is sequentially folded radially inward. However, since the outer thumb area (112) is separated from the inner thumb area (111), the second area (S2) does not move integrally with the first area (S1) and can be separated.

[0086] At this time, the size of the first region (S1) may be larger than the size of the second region (S2). The area of ​​the first region (S1) may be wider than the area of ​​the second region (S2). The number of wound layers included in the first region (S1) may be greater than the number of wound layers included in the second region (S2).

[0087] Referring to FIG. 7, when a thermal event occurs within the battery cell (10), the first region (S1) can quickly exit the battery cell (10) without being obstructed by friction with the side wall (201) of the can (200).

[0088] In addition, according to the above embodiment of the present invention, only the first region (S1), which is an area essential for welding for electrical connection between the can (200) and the electrode assembly (100), is formed as a single mass, and the second region (S2), which is an area located on the outside, can be separated from the first region (S1). Thus, even if only the first region (S1) is smoothly discharged to the outside, it is possible to prevent the electrode assembly (100) from being discharged due to friction with the side wall (201) of the can (200) and remaining inside the battery cell (10), thereby preventing heat transfer to an adjacent battery cell (10).

[0089] Additionally, the outer non-existent portion (112) and the corresponding second region (S2) of the electrode assembly (100) may remain within the battery cell (10). However, by partially removing the heat source, the early termination of the thermal event may be induced. In particular, in the electrode assembly (100), if the number of stacked layers included in the second region (S2) is smaller than the number of stacked layers included in the first region (S1), the effect of removing the heat source inside the battery cell (10) can be sufficiently secured even if the second region (S2) is not discharged outside the battery cell (10).

[0091] FIG. 8 is a drawing illustrating the unfolded state of the first electrode of a battery cell according to one embodiment of the present invention. FIG. 9 is a drawing illustrating the unfolded state of the first electrode of a battery cell according to another embodiment of the present invention.

[0092] The first leg portion (110) can be divided into a plurality of segments (110a) that can be independently folded. The inner leg portion (111) and the outer leg portion (112) of the first leg portion (110) can each be divided into a plurality of first segments (111a) and second segments (112a).

[0093] The segment (110a) may have the shape of a geometric figure with the bend line as its base. The width of the lower part of the segment (110a) may be greater than the width of the upper part. Additionally, the width of the lower part of the segment (110a) may increase gradually or stepwise (not shown) as it goes upward. For example, each of the multiple segments (110a) may be configured so that the upper region of the bend line has the shape of a trapezoid with the bend line as its base.

[0094] According to one embodiment, the outer bare portion (112) may be formed with a shorter length in the winding axis direction than the inner bare portion (111). The second segment (112a) may be formed with a shorter length in the winding axis direction than the first segment (111a). For example, the second segment (112a) of the outer bare portion (112) may be laser-notched. For example, the second segment (112a) of the outer bare portion (112) may be formed by a known metal foil cutting process such as ultrasonic cutting or punching.

[0095] A plurality of segments (110a) of the inner bare portion (111) can be bent along the radial direction of the electrode assembly (100) to form a bent surface area (F). When the first electrode is wound, a plurality of segments (110a) of the inner bare portion (111) can be bent toward the core side of the electrode assembly (100). Here, the core may refer to a cavity in the winding center hole (H) of the electrode assembly (100).

[0096] Referring to FIG. 9, the height of the first segment (111a) of the inner bare portion (111) may be configured to be short on the core side. For example, the core-side portion of the first segment (111a) of the inner bare portion (111) may be notched by a laser. For example, the core-side portion of the first segment (111a) of the inner bare portion (111) may be formed by a known metal foil cutting process such as ultrasonic cutting or punching.

[0097] According to the above embodiment of the present invention, by configuring the height of the first segment (111a) on the core side to be short, a structure in which the first segment (111a) unnecessarily protrudes toward the core side can be prevented.

[0098] FIG. 10 is a cross-sectional view of a battery cell according to another embodiment of the present invention. FIG. 11 is an enlarged view of portion B of FIG. 10 according to another embodiment of the present invention.

[0099] A lead (300) may have a liquid injection port (H1) formed in at least a portion of the area. A liquid injection port (H1) may be formed in the center of the lead (300). At this time, the liquid injection port (H1) may be blocked by a plug (400) to be described later. For example, the plug (400) may be pressed into the liquid injection port (H1). By blocking the liquid injection port (H1) by the plug (400), the battery cell (10) can be sealed.

[0100] The injection port (H1) can serve as, for example, an electrolyte injection port. The center of the injection port (H1) may coincide with the center of the winding center hole (H) of the electrode assembly (100). That is, the injection port (H1) of the lead (300) may be located above the winding center hole (H) of the electrode assembly (100) in the direction of the winding axis.

[0101] The plug (400) can be configured to seal the injection port (H1) formed in the center of the lead (300). That is, the plug (400) can be configured to be inserted into the injection port (H1). At least a portion of the plug (400) can penetrate the injection port (H1). By inserting the plug (400) into the injection port (H1) of the lead (300), the sealing of the battery cell (10) can be ensured. The plug (400) penetrates the injection port (H1) formed in the lead (300) to seal the outside and inside of the can (200) and prevent leakage of the electrolyte.

[0102] The lid (300) may have a step formed in the radial direction relative to the periphery of the injection port (H1). The lid (300) may further include a body portion (320) and an edge portion (330) in addition to the non-removable joint portion (310).

[0103] The body portion (320) may surround the injection port (H1). The body portion (320) may surround the injection port (H1) approximately along the circumferential direction. At least a portion of the body portion (320) may be a portion where the plug (400) is seated. The portion of the body portion (320) where the plug (400) is seated may be formed to be thinner than the rest of the body portion (320). For example, the step of the body portion (320) may be formed by forging.

[0104] The body portion (320) may be positioned so as to be spaced apart from the electrode assembly (100) in the direction of the winding axis. That is, the body portion (320) may be positioned above the non-reinforced portion (310) in the direction of the winding axis. According to the above embodiment of the present invention, the height of the body portion (320) in the direction of the winding axis adjacent to the welded portion of the lead (300) and the plug (400) is formed high, thereby blocking the direct transfer of welding heat to the electrode assembly (100). Accordingly, damage such as the separator of the electrode assembly (100) unraveling or the separator of the electrode assembly (100) melting due to thermal or physical shock caused by welding heat can be prevented.

[0105] The non-reinforced joint portion (310) may be located between the body portion (320) and the edge portion (330) based on the radial direction. That is, the body portion (320), the non-reinforced joint portion (310), and the edge portion (330) of the lead (300) may be arranged sequentially along the radial direction.

[0106] The non-recessed joint portion (310) may be formed by being recessed inward toward the electrode assembly (100). The bottom surface of the non-recessed joint portion (310) may be provided closest to the electrode assembly (100) than the remaining bottom surface of the lead (300). In this case, when the non-recessed joint portion (310) is joined to the electrode assembly (100), the remaining portion of the lead (300), excluding the non-recessed joint portion (310), may be spaced apart from the electrode assembly (100).

[0107] The non-reinforced portion joining part (310) may face at least a portion of the folded surface area (F) formed by the inner non-reinforced portion (111). The non-reinforced portion joining part (310) may be welded to at least a portion of the folded surface area (F) formed by the inner non-reinforced portion (111).

[0108] According to the above embodiment of the present invention, the non-recessed joint portion (310) can be formed by being recessed in an intaglio, so that contact with the electrode assembly (100) can be formed more stably. The lead (300) according to one embodiment of the present invention can have improved welding quality with the electrode assembly (100).

[0109] The non-reinforced coupling portion (310) may be extended toward the body portion (320) and the edge portion (330). Specifically, the non-reinforced coupling portion (310) may be extended radially inward (centripetal direction) toward the body portion (320), and the non-reinforced coupling portion (310) may be extended radially outward (centrifugal direction) toward the edge portion (330). According to the above embodiment of the present invention, since the welding length (LFW, Lid Foil tab welding) between the non-reinforced coupling portion (310) and the first non-reinforced portion (110) can be secured long, the internal resistance of the battery cell can be reduced.

[0110] The edge portion (330) may be positioned at the edge of the lid (300) so as to be joined to the can (200). The edge portion (330) may be joined by a press fit to an open end formed on one side of the can (200). The edge portion (330) may be joined to the can (200) by welding after being press-fitted to one side of the can (200). For example, the cross-section of the edge portion (330) may be approximately U-shaped. However, the shape of the edge portion (330) is not limited by the above embodiment and may be modified in various ways.

[0111] The end of the edge portion (330) that is close to the electrode assembly (100) may be spaced apart from the electrode assembly (100). The edge portion (330) may be located in the outer direction (upward direction) in the winding axis direction than the unwound portion coupling portion (310). Additionally, an outer unwound portion (112) may be located in the area corresponding to the vertical direction of the edge portion (330).

[0112] According to the above embodiment of the present invention, with reference to FIGS. 10 and FIGS. 11, the outer bare portion (112) may have a shape that extends upward without being folded. That is, the notching process may be omitted for the outer bare portion (112). Alternatively, it may be configured so that only at least a portion of the outer bare portion (112) is notched. According to the above embodiment of the present invention, even if the outer bare portion (112) is not cut, it may not come into contact with the lead (300) and may be separated without being combined with the inner bare portion (111). Since the notching process is omitted, the manufacturing process can be simplified and manufacturing efficiency can be increased.

[0113] Meanwhile, the lid (300) may further be provided with a vent portion (340). The vent portion (340) may be located between the edge portion (330) and the non-reinforced portion (310). The vent portion (340) may be configured to rupture due to the internal pressure of high-temperature venting gas when a thermal event occurs within the battery cell (10). That is, the vent portion (340) may rupture when the pressure inside the can (200) exceeds a critical threshold. Accordingly, the venting gas formed within the battery cell (10) may be discharged from the battery cell (10) to the outside.

[0114] The vent portion (340) may be formed by notching. The vent portion (340) may be formed by notching along the circumferential direction. The thickness of the vent portion (340) may be formed thinner compared to other areas of the lead (300). The vent portion (340) may be formed on one or both sides of the lead (300). For example, the vent portion (340) may be formed on the upper surface and / or lower surface of the lead (300). For example, the vent portion (340) may be implemented as a thin-walled portion with notching on both surfaces of the lead (300).

[0115] According to the above embodiment of the present invention, the vent portion (340) is formed thinner compared to the surrounding area, so it can be broken more easily than the surrounding area. That is, when the pressure inside the can (200) increases above a certain level, the vent portion (340) breaks, and the gas and / or electrode assembly (100) generated inside the can (200) can be discharged more easily.

[0116] At this time, the outer thumb area (112) may be located radially outward with respect to the vent area (340), and the inner thumb area (111) may be located radially inward with respect to the vent area (340). That is, the outer thumb area (112) and the inner thumb area (111) may be divided based on the area corresponding in the vertical direction to the vent area (340).

[0117] According to the above embodiment of the present invention, when a thermal event occurs within the battery cell (10), the inner non-existent portion (111) can be discharged more smoothly and quickly to the outside of the battery cell (10). That is, when the inner non-existent portion (111) and the first area (S1) of the area corresponding to the inner non-existent portion (111) are discharged to the outside of the battery cell (10), they can be easily discharged without hitting or being obstructed by the vent portion (340) and the lead (300) connected to the vent portion (340).

[0118] FIG. 12 is a cross-sectional view of a battery cell according to another embodiment of the present invention. FIG. 13 is an enlarged view of portion C of FIG. 12 according to another embodiment of the present invention.

[0119] The outer bare portion (112) can be configured to be electrically coupled with the can (200). The outer bare portion (112) can come into direct contact with the can (200).

[0120] The outer bare portion (112) can be bent outward in a radial direction. The outer bare portion (112) bent outward in a radial direction can be joined to the inner surface of the side wall portion (201) of the can (200) while overlapping each other. For example, the outer bare portion (112) can be bent one by one during the process of forming the electrode assembly (100). Alternatively, for example, the outer bare portion (112) can be bent all at once after forming the electrode assembly (100).

[0121] According to the above embodiment of the present invention, since the outer unoccupied portion (112) is directly coupled to the can (200), the area of ​​the electrically connected first unoccupied portion (110) can be increased. Accordingly, the internal resistance of the battery cell (10) can be reduced.

[0122] FIG. 14 is a drawing for explaining a battery pack according to an embodiment of the present invention. FIG. 15 is a drawing for explaining a vehicle including the battery pack of FIG. 14.

[0123] Referring to FIG. 14, the battery pack (1) according to the present invention may include at least one battery cell (10) according to the present invention as described above. Additionally, the battery pack (1) according to the present invention may include a pack housing (2) capable of accommodating at least one battery cell (10). The battery pack (1) may be constructed using a battery module, which is an intermediate form of assembly, or the battery pack (1) may be constructed directly without a battery module as illustrated. Since the battery cell (10) itself has a large volume, there may be no particular difficulty in implementing the battery pack (1) even without using an intermediate structure called a battery module.

[0124] In addition, the battery pack (1) may further include various other components in addition to the battery cell (10), such as a BMS, a pack case, a relay, a current sensor, etc., components of the battery pack (1) known at the time of filing the present invention.

[0125] A battery pack (1) may include a plurality of battery cells (10). The battery cells (10) may be arranged in a predetermined number of rows, and each battery cell (10) may be arranged such that an electrode terminal (220 in FIG. 3) having a first polarity and an electrode terminal (210 in FIG. 3) having a second polarity are both positioned on the upper side. Therefore, when electrically connecting a plurality of battery cells (10), both positive and negative electrodes can be connected in one direction, thereby simplifying the electrical connection structure. Through this, the number of battery cells (10) that can be mounted in the same space can be increased to improve energy density, and electrical wiring work can be performed easily. Therefore, space efficiency is good and electrical wiring efficiency is high, resulting in significant work improvement effects during the assembly process of an electric vehicle and during the assembly and maintenance of the battery pack (1). Additionally, as previously explained, each battery cell (10) may have a higher energy density than conventional ones. The battery pack (1) with such increased energy density can store the same amount of energy while reducing its volume and load.

[0126] Therefore, if a battery pack (1) with such battery cells (10) is installed in a vehicle such as a car (V) that uses electricity as an energy source as shown in FIG. 14, the vehicle's mileage relative to energy can be further increased.

[0127] In addition, since electrical wiring is performed on the side where the bottom part (202) of the can (200) and the electrode terminal (210) are located, and electrical wiring may not be placed on the lead (300) located on the opposite side, the effect of the vent can be maximized if a vent part is configured on the lead (300) so that it can be vented toward the lead (300). Also, if a heat sink, cooling plate, or tray is placed on the side of the lead (300), purposes such as assembly and cooling can be effectively achieved regardless of the electrical wiring connection part. Furthermore, by assembling the vent part so that it is positioned downward, the gas discharged from inside the secondary battery is discharged downward. Since secondary batteries are usually mounted at a position lower than the occupants of vehicles such as EVs, if gas is discharged upward from the secondary battery, it can cause harm to the occupants. The battery cell (10) of the present invention is not only capable of effectively discharging high-pressure gas inside the secondary battery, but is also safe as it is independent of the upper electrical wiring connection part, and furthermore, since the gas is discharged downward when the vent part breaks and does not cause harm to the occupant, the safety is greatly improved.

[0128] Referring to FIG. 15, the automobile (V) according to the present invention may include at least one battery pack (1) according to the present invention.

[0129] The battery cell (10) according to the present invention can be applied to a vehicle such as an electric vehicle or a hybrid vehicle. That is, the vehicle (V) according to the present invention may include the battery cell (10) according to the present invention or the battery pack (1) according to the present invention. In addition, the vehicle (V) according to the present invention may further include various other components included in the vehicle in addition to the battery cell (10) or the battery pack (1). For example, the vehicle (V) according to the present invention may further include a vehicle body, a motor, a control device such as an ECU (electronic control unit), in addition to the battery cell (10) according to the present invention. The vehicle (V) includes four-wheeled vehicles and two-wheeled vehicles. The vehicle (V) may operate by receiving power from the battery pack (1) according to one embodiment of the present invention.

[0130] Although the present invention has been described above by 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

[0132] V : Car 1 : Battery pack 10: Battery cell 100 : Electrode assembly 110: 1st Unintelligible Division 111: Medial thumb 112: Lateral thumb 200 : Can 201 : Sidewall 202 : Bottom part 300 : Lead 310: Joint of thumb area 320 : Body 330 : Edge part 340 : Vent section 400 : Plug

Claims

Claim 1 A battery cell comprising: an electrode assembly in which a first electrode and a second electrode and a separator interposed between them are wound with respect to a winding axis, and a non-retaining portion exposed to the outside of the separator is formed at the ends of the first electrode and the second electrode, respectively; and a can configured to accommodate the electrode assembly through an open end formed on one side; wherein the first non-retaining portion formed at the end of the first electrode comprises an inner non-retaining portion configured to be electrically connected to the can and an outer non-retaining portion located radially outside the inner non-retaining portion and configured not to be coupled to the inner non-retaining portion. Claim 2 A battery cell according to claim 1, further comprising a lead covering the open end, the lead having a non-removable portion coupling portion configured such that at least a portion of the inner surface is electrically connected to a first electrode; wherein the inner non-removable portion is configured to be connected to the non-removable portion coupling portion. Claim 3 A battery cell according to claim 2, characterized in that the outer non-reinforced portion is positioned radially outward from a position corresponding in the vertical direction to the non-reinforced portion coupling portion. Claim 4 A battery cell according to claim 2, wherein the inner bare portion is folded inward in a radial direction to form a folded surface area while overlapping each other, and at least a portion of the folded surface area is in contact with the bare portion joining portion. Claim 5 A battery cell characterized in that, in claim 2, the above-mentioned non-reinforced coupling portion is formed by being recessed in a direction toward the electrode assembly. Claim 6 A battery cell according to claim 2, further comprising a plug configured to seal an injection port formed in the center of the lead, wherein the lead further comprises a body portion on which the plug is seated and an edge portion located at the edge of the lead, and wherein the non-removable portion coupling portion is located between the body portion and the edge portion with respect to the radial direction. Claim 7 A battery cell according to claim 6, wherein a vent portion is further provided between the edge portion and the non-reinforced portion joining portion, the outer non-reinforced portion is located radially outward with respect to the vent portion, and the inner non-reinforced portion is located radially inward with respect to the vent portion. Claim 8 A battery cell according to claim 1, characterized in that, when a thermal event occurs within the battery cell, the inner non-discharge portion is configured to be discharged to the outside of the battery cell. Claim 9 A battery cell according to claim 1, characterized in that the outer blank portion is configured to be electrically coupled with the can. Claim 10 A battery cell according to paragraph 2, characterized in that the lead is configured to be joined to the open end of the can by welding. Claim 11 A battery pack comprising a battery cell according to any one of claims 1 to 10. Claim 12 An automobile comprising a battery cell according to any one of paragraphs 1 through 10.

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