Battery cell, and battery pack and vehicle comprising same

Abstract

A battery cell according to one embodiment of the present invention may comprise: an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound about a winding axis so as to define a core and an outer circumferential surface, the first electrode including a first uncoated portion, which is not coated with an active material layer along a winding direction; a battery housing having an open portion formed at one side thereof, and accommodating the electrode assembly therein through the open portion; a current collector, which is disposed at one side of the electrode assembly and electrically connects the first uncoated portion to the battery housing; and a housing cover covering the open portion, wherein the current collector includes: a support portion disposed to face the first uncoated portion of the electrode assembly and electrically connected to the first uncoated portion; and a plurality of housing coupling portions extending from the support portion, each having one end portion coupled to the battery housing and electrically connected to the battery housing, and at least one housing coupling portion from among the plurality of housing coupling portions has a fracture zone having a lower strength than a peripheral region.

Description

Battery cells, battery packs including the same, and automobiles

[0001] The present invention relates to a battery cell, a battery pack including the same, and an automobile. This application is a priority claim application based on Korean Patent Applications No. 10-2024-0194486 and No. 10-2024-0194487 filed on December 23, 2024. All contents disclosed in the specifications and drawings of the said Korean applications are incorporated by reference into this application.

[0002] Secondary batteries, which possess electrical characteristics such as high energy density and high applicability across product groups, are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) powered by electric sources. These secondary batteries are attracting attention as a new energy source for enhancing eco-friendliness and energy efficiency, as they possess not only the primary advantage of drastically reducing the use of fossil fuels but also the advantage of generating no by-products from energy use.

[0003] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells, or unit battery cells, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, multiple battery cells are connected in series to form a battery pack. Additionally, depending on the charge / discharge capacity required for the battery pack, multiple battery cells are connected in parallel to form a battery pack. Accordingly, the number of battery cells included in the battery pack can be varied depending on the required output voltage and / or charge / discharge capacity.

[0004] Meanwhile, in relation to electric vehicle fires that have recently become a major issue, battery safety is considered very important not only by the battery industry but also by society as a whole. In the case of conventional cylindrical battery cells, when a thermal event occurs within the battery cell, the venting part is damaged and the housing cover opens, allowing flames and residue to escape, thereby facilitating rapid fire suppression and preventing additional ignition of adjacent battery cells.

[0005] However, in the case of conventional battery cells, the current collector remains coupled to the electrode assembly (jelly-roll) even after the housing cover is opened, and there is a problem in that the discharge of flames and residues is obstructed by this electrode assembly.

[0006] One objective of the present invention is to provide a current collector with an improved structure that facilitates the discharge of flames and residues in the event of a fire in a battery cell, and a battery cell equipped with the same.

[0007] However, 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.

[0008] A battery cell according to an embodiment of the present invention for solving the above-described problem comprises an electrode assembly in which a first electrode and a second electrode and a separator interposed between them are wound around a winding axis to define a core and an outer surface, wherein the first electrode comprises an electrode assembly including a first blank portion in which an active material layer is not coated along the winding direction; a battery housing having an opening formed on one side and accommodating the electrode assembly inside through the opening; a current collector disposed on one side of the electrode assembly and electrically connecting the first blank portion and the battery housing; and a housing cover covering the opening. The current collector comprises a support portion disposed facing the first blank portion of the electrode assembly and electrically connected to the first blank portion, and a plurality of housing coupling portions extending from the support portion and having one end coupled to the battery housing and electrically connected to the battery housing, wherein at least one of the plurality of housing coupling portions may have a fracture zone having a lower strength than the surrounding area.

[0009] In one aspect of the present invention, the housing coupling portion includes a contact portion coupled to the battery housing and a connecting portion connecting the contact portion and the support portion, and the fracture zone may be formed in the connecting portion.

[0010] In addition, the fracture zone may be provided in an area adjacent to the contact portion at the connection portion.

[0011] In addition, the fracture zone may be provided in an area adjacent to the support at the connection part.

[0012] In addition, a plurality of through holes may be formed through the fracture zone.

[0013] In addition, the plurality of through holes may include through holes having different sizes or shapes.

[0014] In addition, the through holes may be formed more on the outer side of the fracture zone than on the central side of the fracture zone.

[0015] In addition, the through holes may be formed more frequently on the central side of the fracture zone than on the outer side of the fracture zone.

[0016] In addition, the fracture zone may include a second material having lower thermal durability compared to the first material constituting the surrounding area.

[0017] Additionally, the battery housing has a beading portion formed at an end adjacent to the opening and pressed inward, and the housing coupling portion includes a contact portion coupled to the beading portion and a connecting portion connecting the contact portion and the support portion, and the fracture zone may be formed in an area including at least a portion of the contact portion.

[0018] In addition, the second material may include zinc (Zn).

[0019] In addition, a plurality of through holes may be formed in the fracture zone.

[0020] In addition, the fracture zone is formed in the width direction of the connection part and may have an area made of the first material and an area made of the second material.

[0021] In addition, the area formed by the second material may be located at both edges based on the width direction of the connection part.

[0022] In addition, the area formed by the second material may be located in the center based on the width direction of the connection part.

[0023] In addition, the area formed by the first material and the area formed by the second material may be arranged alternately.

[0024] In addition, the housing joint may be provided with a fracture acceleration member located adjacent to the fracture zone, which accelerates the fracture of the fracture zone by concentrating heat or pressure generated inside the battery housing into the fracture zone.

[0025] Additionally, the housing coupling portion includes a contact portion coupled to the battery housing and a connecting portion connecting the contact portion and the support portion, the fracture zone is formed in the connecting portion, and the fracture acceleration portion is located adjacent to the fracture zone and can be formed extending outward from the connecting portion.

[0026] In addition, a plurality of micro-holes may be formed through the fracture acceleration part.

[0027] In addition, the fracture acceleration part may have an uneven structure formed along its circumference.

[0028] In addition, the fracture zone may be formed with a thinner thickness than the surrounding area.

[0029] In addition, the plurality of housing joints are arranged radially around the support member, and the housing joints having the fracture zones can be arranged asymmetrically around the support member.

[0030] Meanwhile, the present invention provides a battery pack comprising at least one battery cell according to the above-described embodiment as a battery pack.

[0031] In addition, the present invention provides a vehicle comprising at least one battery pack according to the above-described embodiment.

[0032] A current collector according to an embodiment of the present invention for solving the above-described problem is a current collector applied to a battery cell comprising an electrode assembly in which a first electrode and a second electrode and a separator interposed between them are wound around a winding axis, wherein the first electrode includes a first blank portion in which an active material layer is not coated along the winding direction, and a battery housing that accommodates the electrode assembly internally through an opening formed on one side and is electrically connected to the first blank portion. The current collector comprises a support portion disposed facing the first blank portion of the electrode assembly and electrically connected to the first blank portion, and a plurality of housing coupling portions extending from the support portion, wherein one end of each housing coupling portion is coupled to the battery housing and electrically connected to the battery housing, wherein a fracture zone having a lower strength than the surrounding area may be formed in at least one of the plurality of housing coupling portions.

[0033] In addition, a plurality of through holes may be formed through the fracture zone.

[0034] In addition, the plurality of housing joints are arranged radially around the support member, and the housing joints having the fracture zones can be arranged asymmetrically around the support member.

[0035] According to one aspect of the present invention, when the housing cover is opened due to a thermal event occurring inside the battery cell, the current collector that was partially blocking the opening of the battery housing can also be rapidly damaged. More specifically, the fracture zone of the current collector is rapidly damaged due to heat and pressure, and consequently, the current collector can be quickly separated from the battery housing and electrode assembly and discharged to the outside of the battery housing. Accordingly, flames and residues can be smoothly discharged through the opening, thereby blocking the propagation of flames to surrounding battery cells.

[0036] 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.

[0037] FIG. 1 is a drawing for illustrating a battery cell according to one embodiment of the present invention.

[0038] Figure 2 is a longitudinal perspective view of Figure 1.

[0039] Figure 3 is a cross-sectional view of the battery cell of Figure 1.

[0040] Figure 4 is a schematic perspective view of the entire house shown in Figure 2.

[0041] Figure 5 is a plan view of the current collector shown in Figure 4 coupled to the battery housing.

[0042] FIG. 6 is a partial diagram illustrating the location of a fracture zone in a current collector according to another embodiment of the present invention.

[0043] FIG. 7 is a partial diagram illustrating the location of a fracture zone in a current collector according to another embodiment of the present invention.

[0044] FIG. 8 is a partial diagram illustrating the structure of a fracture zone according to one embodiment of the present invention.

[0045] FIG. 9 is a partial diagram illustrating the structure of a fracture zone according to another embodiment of the present invention.

[0046] FIG. 10 is a partial diagram illustrating the structure of a fracture zone according to another embodiment of the present invention.

[0047] FIG. 11 is a partial diagram illustrating the structure of a fracture zone according to another embodiment of the present invention.

[0048] FIG. 12 is a drawing for explaining the location of a fracture zone according to another embodiment of the present invention.

[0049] FIG. 13 is a drawing for explaining the location of a fracture zone according to another embodiment of the present invention.

[0050] FIG. 14 is a drawing for explaining the location of a fracture zone according to another embodiment of the present invention.

[0051] FIG. 15 is a partial diagram illustrating the structure of a fracture zone according to another embodiment of the present invention.

[0052] FIG. 16 is a partial diagram illustrating the structure of a fracture zone according to another embodiment of the present invention.

[0053] FIG. 17 is a partial diagram illustrating the structure of a fracture zone according to another embodiment of the present invention.

[0054] FIG. 18 is a partial diagram illustrating the structure of a fracture zone according to another embodiment of the present invention.

[0055] FIG. 19 is a partial enlarged view of a current collector according to another embodiment of the present invention.

[0056] FIG. 20 is a partial enlarged view of a current collector according to another embodiment of the present invention.

[0057] FIG. 21 is a plan view of a current collector coupled to a battery housing according to another embodiment of the present invention.

[0058] FIG. 22 is a drawing for illustrating a battery pack including a battery cell according to one embodiment of the present invention.

[0059] FIG. 23 is a drawing for explaining a vehicle including the battery pack of FIG. 22.

[0060]

[0061]

[0062] 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. Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention; therefore, it should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0063] 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.

[0064] The statement that two subjects of comparison are identical means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0065] 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.

[0066] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0067] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0068] 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.

[0069] 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.

[0070] For convenience of explanation, in this specification, the direction following the longitudinal direction of the winding axis of the electrode assembly (10) wound in a jelly roll shape is referred to as the axial direction. The direction approaching or moving away from the winding axis is referred to as the radial direction. The direction surrounding the winding axis is referred to as the circumferential direction or the periphery direction. In particular, among the radial directions, 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.

[0071]

[0072] The present invention relates to a battery cell, a battery pack, and an automobile including the same.

[0073] The current collector is applied to a battery cell, and the battery cell includes an electrode assembly having two electrodes, a battery housing that accommodates the electrode assembly inside through an opening formed at one end, a current collector, and a housing cover that closes the opening of the battery housing.

[0074] Here, the current collector is intended to electrically connect the electrodes of the electrode assembly to the battery housing; therefore, explaining the composition, purpose, and effect of the current collector in conjunction with other components of the battery cell allows for a more detailed explanation. Accordingly, the battery cell and the current collector will be explained together below, followed by an explanation of the battery module, battery pack, and vehicle.

[0075]

[0076] FIG. 1 is a drawing for explaining a battery cell (1) according to an embodiment of the present invention, and FIG. 2 is a cross-sectional perspective view of FIG. 1. FIG. 3 is a cross-sectional view of the battery cell (1) of FIG. 1.

[0077] Referring to FIG. 1, a battery cell (1) according to one embodiment of the present invention may include an electrode assembly (10), a battery housing (20), a current collector (30), and a housing cover (40). The battery cell (1) may further include a terminal (50) and / or a sealing gasket (G1) and / or an insulating gasket (G2) and / or a second current collector (60) and / or an insulator (70). The present invention is not limited by the shape of the battery and is applicable to batteries of other shapes, such as prismatic batteries.

[0078] The electrode assembly (10) may have a first blank portion (11) and a second blank portion (12). More specifically, the electrode assembly (10) has a structure in which the first electrode and the second electrode and the separator interposed between them are wound around a winding axis with a separator interposed between them, thereby defining a core and an outer surface. That is, the electrode assembly (10) applied to the present invention may be a jelly-roll type electrode assembly (10). In this case, an additional separator may be provided on the outer surface of the electrode assembly (10) to provide insulation from the battery housing (20). The electrode assembly (10) may have a winding structure well known in the art without limitation.

[0079] The first electrode comprises a first electrode current collector and a first electrode active material applied on one or both sides of the first electrode current collector. At one end of the first electrode in the width direction (a direction parallel to the height direction of the battery cell (1) shown in FIG. 1), there is a blank portion where the first electrode active material is not applied. That is, the first electrode includes a blank portion exposed to the outside of the separator, where the active material is not coated at the long end along the winding direction. The blank portion functioning as a first electrode tab will hereinafter be referred to as the first blank portion (11). The first blank portion (11) is provided on the upper side in the height direction (a direction parallel to the height direction of the battery cell (1) shown in FIG. 1) of the electrode assembly (10) housed within the battery housing (20). That is, the first electrode includes a first uncoated portion (11) that is exposed to the outside of the separator and has no active material layer coated on the long side end, and at least a portion of the first uncoated portion (11) is used as an electrode tab itself. The first uncoated portion (11) may be, for example, a negative electrode tab.

[0080] Meanwhile, at least a portion of the first blank portion (11) may include a plurality of segments divided along the winding direction of the electrode assembly (10). In this case, the plurality of segments may be bent along the radial direction of the electrode assembly (10).

[0081] Referring to FIGS. 2 and 3, a plurality of segments of the first bare section (11) that have been bent may be overlapped in multiple layers to form a folded surface. In this case, the tab connecting part (312) of the current collector (30), which will be described later, may be connected to the folded surface. The tab connecting part (312) may be connected to an area where a plurality of segments are overlapped in multiple layers. In this case, welding may be performed on a certain area while the tab connecting part (312) is seated on the folded surface of the first bare section (11). That is, the tab connecting part (312) may be connected to an area where a plurality of segments of the first bare section (11) are overlapped in multiple layers.

[0082] The second electrode comprises a second electrode current collector and a second electrode active material applied on one or both sides of the second electrode current collector. At the other end of the second electrode in the width direction (a direction parallel to the height direction of the battery cell (1) shown in FIG. 1), there exists a blank portion where the second electrode active material is not applied. That is, the second electrode includes a blank portion exposed to the outside of the separator, where the active material is not coated at the long end along the winding direction. The blank portion functioning as a second electrode tab is hereinafter referred to as the second blank portion (12). The second blank portion (12) is provided at the lower end in the height direction of the electrode assembly (10) housed within the battery housing (20). That is, the second electrode includes a second blank portion (12) where the active material layer is not coated at the long end and is exposed to the outside of the separator, and at least a portion of the second blank portion (12) is used as an electrode tab itself. The above second blank part (12) may be, for example, an anode tab.

[0083] Meanwhile, in the present invention, 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.

[0084]

[0085] Referring to FIGS. 1 to 3, the battery housing (20) is a roughly cylindrical receptacle with an opening formed on one side and a hollow interior, and may include a conductive metal material. It is common for the side of the battery housing (20) and the bottom surface located opposite the opening to be formed integrally. That is, the battery housing (20) generally has one end open and the opposite end closed based on its height direction. For example, referring to FIG. 2, the top of the battery housing (20) may be open and the bottom may be closed. The bottom surface of the battery housing (20) may have a roughly flat shape. The battery housing (20) accommodates an electrode assembly (10) inside through the opening formed at the top. The battery housing (20) may also accommodate an electrolyte through the opening.

[0086] The battery housing (20) may have a beading portion (21) formed at an end adjacent to an opening provided at the top of the battery housing (20). The battery housing (20) may further have a crimping portion (22) formed on the beading portion (21). The beading portion (21) has a shape in which the outer circumference of the battery housing (20) is indented to a predetermined depth. More specifically, the beading portion (21) may have a shape in which it is indented inward in the area between an opening formed on one side of the battery housing (20) and a receiving portion that accommodates the electrode assembly (10).

[0087] The beading portion (21) is formed on the upper part of the electrode assembly (10). The inner diameter of the battery housing (20) in the area where the beading portion (21) is formed is formed to be smaller than the diameter of the electrode assembly (10). At least one tab coupling portion (312) of the current collector (30), which will be described later, may be located further down than the beading portion (21).

[0088] The beading portion (21) provides a support surface on which the housing cover (40) can be seated. Additionally, the beading portion (21) may provide a support surface on which at least a portion of the perimeter of the current collector (30), which will be described later, can be seated and joined. That is, at least a portion of the perimeter of the current collector (30) of the present invention and / or the perimeter of the housing cover (40) can be seated on the upper surface of the beading portion (21). In order to stably support at least a portion of the perimeter of the current collector (30) and / or the perimeter of the housing cover (40), the upper surface of the beading portion (21) may have a shape that extends along a direction approximately parallel to the lower surface of the battery housing (20), that is, along a direction approximately perpendicular to the side wall of the battery housing (20).

[0089] The above beading portion (21) prevents the electrode assembly (10), which may have a size approximately corresponding to the inner diameter of the battery housing (20), from coming out through the opening formed at the top of the battery housing (20), and can function as a support portion on which the housing cover (40) is seated. The above upper beading portion (21) can function as a support portion for fixing not only the housing cover (40) but also the contact portion (322) of the current collector (30), the sealing gasket (G1), etc.

[0090] The above-mentioned clamping portion (22) is formed on the upper part of the beading portion (21). The clamping portion (22) has an extended and banded shape to wrap around the perimeter of the edge of the housing cover (40) placed on the upper part of the beading portion (21). Due to the shape of this clamping portion (22), the housing cover (40) is fixed on the beading portion (21).

[0091]

[0092] Next, with reference to FIGS. 1 to 3 and FIGS. 4 and FIGS. 5, a current collector (30) according to an embodiment of the present invention will be described in detail.

[0093] FIG. 4 is a schematic perspective view of the current collector shown in FIG. 2, and FIG. 5 is a plan view of the current collector shown in FIG. 4 coupled to a battery housing.

[0094] First, referring to FIGS. 2 and 3, a current collector (30) according to one embodiment of the present invention is housed inside a battery housing (20) and can be positioned on one side of an electrode assembly (10). The current collector (30) is electrically connected to the electrode assembly (10), more specifically to the first non-removable portion (11) of the electrode assembly, and can also be electrically connected to the battery housing (20). That is, the current collector (30) electrically connects the electrode assembly (10) and the battery housing (20).

[0095] Referring to FIGS. 4 and FIGS. 5, the current collector (30) may include a support portion (31) and a housing coupling portion (32).

[0096] The support member (31) may be positioned on one side of the electrode assembly, specifically facing the side where the first non-removable portion (11) is formed. The support member (31) may include a body portion (311) and a tab coupling portion (312).

[0097] The above body part (311) is formed in a plate shape, and a current collector hole (H2) may be formed through the center to correspond to a winding hole (H1). The winding hole (H1) and the current collector hole (H2), which are in communication with each other, can function as a passage for inserting a welding rod for welding between the terminal (50) and the second current collector (60) to be described later, or for welding between the terminal (50) and the lead tab (not shown), or for irradiating a laser beam. The current collector hole (H2) may have a diameter substantially the same as or larger than the winding hole (H1) of the electrode assembly (10) so as not to obscure the winding hole (H1) formed in the core of the electrode assembly (10). If the diameter of the current collector hole (H2) is excessively smaller than the diameter of the winding hole (H1), the hole formed in the winding hole (H1) may be obscured, which may reduce liquid injection performance, and it may also be difficult to secure sufficient space for inserting a welding device or laser irradiation.

[0098] The above-mentioned tab connecting portion (312) may be formed to extend outward from the body portion (311). The above-mentioned tab connecting portion (312) is connected to the first bare portion (11) by means such as welding, thereby allowing the tab connecting portion (312) to be electrically connected to the first bare portion (11). At least one tab connecting portion (312) is provided, and as shown in FIG. 4, a plurality of tab connecting portions (312) may be arranged approximately radially, crosswise, or in a combined form around the body portion (311). Meanwhile, not only the above-mentioned tab connecting portion (312), but also the above-mentioned body portion (311) may be connected to the first bare portion (11) by welding.

[0099] The housing coupling portion (32) is formed extending from the support portion (31), more specifically the body portion (311) of the support portion, and can be coupled to the battery housing (20) and electrically connected. The housing coupling portion (32) can be indirectly connected to the tab coupling portion (312) through the body portion (311), and thus may not be directly connected to each other. Therefore, when an external impact is applied to the battery cell (1) of the present invention, the possibility of damage occurring to the coupling portion between the current collector (30) and the electrode assembly (10) and the coupling portion between the current collector (30) and the battery housing (20) can be minimized.

[0100] The above housing coupling portion (32) may be provided in multiple numbers, and the multiple housing coupling portions (32) may be arranged radially around the body portion (311) of the support portion (31). For example, as shown in FIG. 5, four housing coupling portions (32) may be provided, and one may be arranged between the tab coupling portions (312) to form a radial structure.

[0101] A fracture zone (P) having lower strength than the surrounding area may be formed in at least one of the plurality of housing joints (32). For example, as shown in FIG. 4, a fracture zone (P) may be formed in all housing joints (32). Alternatively, as described below, a fracture zone may be formed only in some of the housing joints (21) among the plurality of housing joints (32). Furthermore, the strength referred to here includes strength to withstand high temperature and high pressure conditions that occur during a battery cell fire, i.e., at least one of thermal durability and durability against external forces. The location where the fracture zone (P) is formed, the structure of the fracture zone, and the effects resulting from such location and structure will be explained in detail later.

[0102]

[0103] The housing cover (40) can cover an opening formed on one side of the battery housing (20). The housing cover (40) can be secured by a clamping portion (22) formed on the top of the battery housing (20). In this case, a sealing gasket (G1) may be interposed between the battery housing (20) and the housing cover (40) and between the current collector (30) and the housing cover (40) to improve the fixing force and the sealing performance of the battery housing (20).

[0104] Additionally, the housing cover (40) may be provided with a venting section (41). The venting section (41) may be configured to break when the internal pressure of the battery housing increases above a certain level. For example, the venting section (41) may be formed in a part of the housing cover (40) and may be a structurally weaker area than the surrounding area so that it can easily break when internal pressure is applied. The venting section (41) may be, for example, an area having a thinner thickness compared to the surrounding area. The venting section (41) may form a roughly circular closed loop.

[0105]

[0106] In a battery cell (1) configured in this manner, if a thermal event occurs inside the battery cell (1) for any reason, venting gas may be generated, and the pressure and temperature inside the battery housing (20) may increase due to the venting gas. At this time, since the venting portion (41) corresponds to a structurally weaker area than the surrounding area so that it can be easily broken when the internal pressure of the battery cell (1) increases, a break may occur in the venting portion (41), causing the inner area of ​​the venting portion (41) to be torn and separated, and as a result, the opening may be opened.

[0107] During this process, heat and pressure are also transferred to the collector (30), and a fracture zone (P) with weak strength in the collector (30) may be damaged. When the fracture zone (P) is damaged, the housing joint (32) is separated into two parts centered on the fracture zone (P), and each part bends upward in the direction in which flames, venting gas, and residues are ejected, and accordingly, the passage that was blocked by the housing joint can be opened. Thus, flames and residues can be discharged smoothly.

[0108] As an additional effect, if the fracture zone (P) of all housing joints is damaged, the electrical connection between the battery housing (20) and the electrode assembly (10) can be cut off, and accordingly, the fusing characteristics within the battery cell can be enhanced.

[0109]

[0110] Again, with reference to FIGS. 3 to 5, the entire current collection unit will be described, and in particular, the housing joint and the fracture zone formed therein will be described in detail.

[0111] The current collector (30) may include a support portion (31) and a housing coupling portion (32). The support portion (31) may be placed on one side of the electrode assembly (10), specifically facing the side where the first non-removable portion (11) is formed. The support portion (31) may include a body portion (311) and a tab coupling portion (312). The support portion (31) has been described previously, so it will be omitted.

[0112] The housing coupling portion (32) may include a contact portion (322) coupled to the battery housing (20) and a connecting portion (321) connecting the support portion (31) and the contact portion (322). At least one housing coupling portion may be provided. At least one of the tab coupling portions (312) and at least one of the housing coupling portions (32) may be arranged, for example, in a roughly radial, cross-shaped, or combined shape with respect to the center of the current collector (30). In another aspect, each of the plurality of housing coupling portions (32) may be arranged between adjacent tab coupling portions (312).

[0113] The contact portion (322) is coupled to the inner surface of the battery housing (20). In the case where a beading portion (21) is formed on the battery housing (20), the contact portion (322) may be coupled to the beading portion (21) as described above. In this case, for stable contact and coupling, both the beading portion (21) and the contact portion (322) may have a shape that extends along a direction approximately parallel to the lower surface of the battery housing (20), that is, a direction approximately perpendicular to the side wall of the battery housing (20).

[0114] In this case, the contact portion (322) may be interposed between the beading portion (21) of the battery housing and the sealing gasket (G1). The contact portion (322) interposed between the beading portion (21) and the sealing gasket (G1) in this manner may be secured by the bending of the clamping portion (22) extending upward from the beading portion (21).

[0115] Meanwhile, the contact portion (322) can be welded to the upper surface of the beading portion (21). That is, a welding area can be formed on the surface where the upper surface of the beading portion (21) and the contact portion meet. At this time, the welding area can be formed narrower than the upper surface of the beading portion (21).

[0116] The contact portion (322) may have an arc shape that extends circumferentially along the beading portion (21) of the battery housing (20) at least in part. Thus, as shown in FIGS. 4 and 5, the circumferential extension length of the contact portion (322) may be formed to be longer than the width of the connecting portion (321).

[0117] The above connecting portion (321) is formed to extend from the supporting portion (31) to the contact portion (322), and more specifically, it may be formed to extend from the body portion (311) of the supporting portion (31) to the contact portion (322). At this time, the supporting portion (31) may be positioned lower than the contact portion (322). Accordingly, the connecting portion (321) may be configured to include a portion formed at an angle up to the height of the contact portion (322), and a portion that extends parallel to the beading portion (21) after this portion and connects to the contact portion (322). The connecting portion (321) may be formed with a constant width, and at this time, the connecting portion (321) may be formed to have a width equal to or smaller than that of the contact portion (322). And, by connecting the connecting part (321) to the support part (31) and the contact part (322) in this way, the electrode assembly (10) coupled to the support part (31) and the battery housing (20) coupled to the contact part (322) can be electrically connected.

[0118] Meanwhile, a fracture zone (P) is formed in the connection part (321). The fracture zone (P) is a structurally weak area having lower strength than the surrounding area, and may be damaged faster than other parts when a thermal event occurs inside the battery cell. Here, strength may include at least one of the strength to withstand high temperature and high pressure conditions that occur during a battery cell fire, i.e., thermal durability and durability against external forces.

[0119]

[0120] Hereinafter, embodiments regarding the location where a fracture zone is formed and the resulting effects will be described with reference to FIG. 5, FIG. 6, and FIG. 7.

[0121] FIG. 6 is a partial diagram illustrating the location of a fracture zone in a current collector according to another embodiment of the present invention, and FIG. 7 is a partial diagram illustrating the location of a fracture zone in a current collector according to yet another embodiment of the present invention.

[0122] As previously explained with reference to FIG. 5, the fracture zone (P) is formed in the connecting part (321), and may be formed in an area excluding both ends of the connecting part (321), for example, in the central part. When a thermal event occurs inside the cell, if the fracture zone (P) is damaged first, the connecting part (321) is separated into two parts centered on the fracture zone (P), and each part bends upward in the direction in which flames and residues are ejected, and accordingly, the passage that was blocked by the housing joint can be opened. Thus, flames and residues can be discharged smoothly.

[0123]

[0124] Referring to FIG. 6 as another embodiment, the fracture zone (P) may be formed in the area adjacent to the contact portion (322) in the connection portion (321), more specifically, at the boundary surface between the connection portion (321) and the contact portion (322). Here, the contact portion (322) is joined in close contact with the beading portion (21) of the battery housing (20), and the connection portion (321) may be in a state of being suspended in the air without contacting other members. Accordingly, when a thermal event occurs inside the battery cell, there may be a difference in the rate of temperature rise between the contact portion (322) and the connection portion (321). For example, the contact portion (322), which receives rapid heat transfer from the beading portion (21), may heat up faster, and due to this temperature difference, a thermal shock may occur at the boundary surface between the contact portion (322) and the connection portion (321). And, such thermal shock can further accelerate the failure of the fracture zone (P).

[0125] Additionally, as previously explained, the contact portion (322) is welded to the beading portion (21) by means of welding, such as laser welding or ultrasonic welding. During this welding process, thermal damage may accumulate at the boundary surface between the contact portion (322) and the connection portion (321). Therefore, if a fracture zone (P) is formed at this part, i.e., the boundary surface, the fracture of the fracture zone (P) may be accelerated.

[0126]

[0127] Referring to FIG. 7 as another embodiment, the fracture zone (P) may be formed in the area adjacent to the support member (31) in the connection member (321), more specifically at the boundary surface between the body member (311) and the connection member (321). Here, the body member (311) may be in contact with the electrode assembly (10), and the connection member (321) may be suspended in the air without contacting other members. Therefore, when a thermal event occurs inside the battery cell, there may be a difference in the rate of temperature rise between the body member (311) and the connection member (321), and as a result, a thermal shock may occur at the boundary surface between the body member (311) and the connection member (321). Furthermore, such a thermal shock may further accelerate the fracture of the fracture zone (P).

[0128] Additionally, as previously explained, the body portion (311) can be welded to the electrode assembly (10) (more specifically, the first non-reinforced portion (11)). During this welding process, thermal damage may accumulate at the boundary surface between the body portion (311) and the connection portion (321). Therefore, if a fracture zone (P) is formed at this part, i.e., the boundary surface, the fracture of the fracture zone (P) may be accelerated.

[0129]

[0130] Meanwhile, as explained above, the fracture zone (P) is a vulnerable area with lower strength than the surrounding area so that it can be damaged more quickly than other areas when a thermal event occurs. Regarding the method of forming such a fracture zone, two main methods can be considered.

[0131] First, there may be a method to make the structure (shape) of the fracture zone (P) itself weaker than the surrounding area. Making it structurally weak means that when the fracture zone (P) is cut in the vertical direction (i.e., the thickness direction of the fracture zone), the cross-sectional area of ​​the fracture zone (P) becomes smaller. And, a small cross-sectional area of ​​the fracture zone (P) means that the amount of material itself constituting the fracture zone (P) at that point is small, which means that the ability to withstand external forces or heat, i.e., durability (i.e., strength), becomes weak.

[0132] Specifically, methods such as forming a notch line in the fracture zone (P), making the thickness of the fracture zone (P) thin, or making the width of the fracture zone (P) narrower than the surrounding area can be considered. Additionally, as described below, there may be a method of forming a fine through hole in the fracture zone (P), and if a fine through hole is formed, the fracture zone (P) can be rapidly damaged due to the turbulent characteristics of the fluid passing through the through hole.

[0133] Secondly, there may be a method in which the material of the fracture zone itself includes a material with lower durability than the surrounding area. Here, durability may be a concept that includes durability against heat, i.e., melting point, and this will also be explained in detail later.

[0134]

[0135] Hereinafter, with reference to FIGS. 8 to 11, the specific structure of such a fracture zone and the resulting effects will be explained in detail.

[0136] FIG. 8 is a partial diagram illustrating the structure of a fracture zone according to one embodiment of the present invention, FIG. 9 is a partial diagram illustrating the structure of a fracture zone according to another embodiment of the present invention, FIG. 10 is a partial diagram illustrating the structure of a fracture zone according to yet another embodiment of the present invention, and FIG. 11 is a partial diagram illustrating the structure of a fracture zone according to yet another embodiment of the present invention.

[0137]

[0138] As illustrated in FIG. 8, the fracture zone (P1a) may have a structure in which a plurality of through holes (h1) are formed through it. Specifically, a plurality of through holes (h1) may be formed in the width direction of the connecting part (321) in the fracture zone (P1a). At this time, FIG. 8 shows that the through holes (h1) are formed in two rows, but the through holes may be formed in one row or three or more rows.

[0139] It is evident that if a through hole (h1) is formed in this manner, the strength of the fracture zone (P1a) becomes structurally weaker than other areas. In particular, when a thermal event occurs, a high-temperature, high-pressure fluid, namely venting gas and byproducts generated by ignition, flows through the through hole (h1). At this time, the gas entering through the through hole (h1), which is a narrow gap, may have turbulent characteristics. When gas with turbulent characteristics passes through the through hole (h1), the friction between the gas and the through hole (h1) increases, and due to the turbulent characteristics, shock waves (a type of irregular vibration) may be induced in the through hole (h1). Therefore, the fracture zone (P1a) may be damaged rapidly.

[0140]

[0141] As another embodiment of the fracture zone structure, as shown in FIG. 9, a plurality of through holes (h1, h2) are formed in the fracture zone (P1b), wherein the through holes (h1, h2) may include through holes having different sizes or shapes. For example, a circular through hole (h1) and a rectangular through hole (h2) may be formed together. Although not shown in the drawing, through holes of the same shape but different sizes may be formed in a mixed manner.

[0142] When through holes (h1, h2) are formed in this manner, the turbulent characteristics of the gas passing through the through holes (h1, h2) can be further enhanced. That is, the difference in characteristics, such as flow velocity or pressure when passing through, between fluids passing through through holes (h1, h2) of different sizes or shapes increases, and as a result, the turbulent characteristics can be further increased. And, as the turbulent characteristics become stronger in this way, the friction and shock waves transmitted to the through holes (h1, h2) may increase, so the fracture zone (P1b) may be fractured more quickly.

[0143]

[0144] As another embodiment of the fracture zone structure, as shown in FIG. 10, a plurality of through holes (h1) are formed in the fracture zone (P1c), and more may be formed on the outer side than on the central side of the fracture zone (P1c). More specifically, the fracture zone (P1c) is formed in the width direction of the connecting part (321), and the through holes (h1) may be formed more intensively on the outer side of the fracture zone (P1c), more specifically on both edges.

[0145] If through holes are formed in this manner, failure may first occur at the edges of the fracture zone (P1c) where the through holes are concentrated when a thermal event occurs. Furthermore, if failure occurs at the edges, external forces (i.e., pressure, gas friction, shock waves, etc.) are concentrated toward the center of the fracture zone (P1c), so the center may also be rapidly damaged in a chain reaction.

[0146] Further consideration in this regard reveals that if a through hole is formed in the fracture zone (P1c) under conditions where the fracture zone (P1c) has a certain width, the strength of the fracture zone (P1c) is weakened, which has the advantage of allowing it to break quickly in the event of a thermal event. However, in another aspect, the current collector (30) in which the fracture zone (P1c) is formed electrically connects the electrode assembly (10) and the battery housing (20), and if a through hole is formed in the fracture zone (P1c) in this manner, the electrical characteristics in that part may be degraded. Therefore, it may be important to minimize the degradation of electrical characteristics while simultaneously ensuring that the fracture zone (P1c) breaks quickly. In this case, electrical characteristics comprehensively refer to characteristics related to generating and transmitting electrical energy through electrochemical reactions occurring inside the battery cell, and may include, for example, electrical conductivity.

[0147] In this regard, when forming the same number of through holes in the fracture zone, concentrating the through holes on both edges of the fracture zone (P1c) as in the present embodiment, rather than forming them uniformly across the entire width of the fracture zone (P1a) as in FIG. 8, so that the edge portions are fractured first, can be a method to fracture the fracture zone more quickly while minimizing the degradation of electrical characteristics.

[0148]

[0149] As another embodiment of the fracture zone structure, as shown in FIG. 11, a plurality of through holes (ha) are formed in the fracture zone (P1d), and more may be formed in the center than on the outer side of the fracture zone (P1d). More specifically, the fracture zone (P1d) is formed in the width direction of the connecting part (321), and the through holes (h1) may be formed more intensively in the center than on both edges of the fracture zone (P1d).

[0150] When the through hole (h1) is formed in this manner, in the event of a thermal event, damage may first occur in the central part of the fracture zone (P1d) where the through holes (h1) are concentrated. Furthermore, if damage occurs in the central part, the external force is concentrated on the outer side, i.e., the edge, of the fracture zone (P1d), so the outer side may also be rapidly damaged in a chain reaction.

[0151] As previously examined in the embodiment of FIG. 10, forming a through hole in the fracture zone in this manner can be a method to break the fracture zone more quickly while minimizing the degradation of the electrical characteristics of the fracture zone.

[0152]

[0153] Meanwhile, in the embodiments described above, the strength of the fracture zone was weakened by forming a hole in the fracture zone; however, as previously mentioned, the strength of the fracture zone may also be weakened by changing the material of the fracture zone, and this will be explained in detail below.

[0154] Referring again to FIGS. 3 and 4, the housing coupling portion (32) includes a contact portion (322) and a connecting portion (321). The contact portion (322) can be joined to the beading portion (21) of the battery housing by welding or the like. The connecting portion (321) can connect the contact portion (322) and the body portion (311).

[0155] The fracture zone (P) is formed in the connection part (321) and may include a material with lower thermal resistance than the surrounding area. That is, the surrounding area of ​​the fracture zone (P) may be formed by including a first material, and the fracture zone (P) may be formed by including a second material with lower thermal resistance than the first material. More specifically, the remaining part of the connection part (321) excluding the fracture zone (P) may be formed by including the first material, for example, copper (Cu), and the fracture zone (P) may be formed by including zinc (Zn), which has lower thermal resistance than copper. Furthermore, the entire area of ​​the current collector (30) excluding the fracture zone (P) may be formed by including copper, and the fracture zone (P) may be formed by including zinc.

[0156] When the fracture zone (P) is formed in this manner, the fracture zone (P), which has relatively low thermal durability, may be damaged first due to reasons such as melting when a thermal event occurs. Then, the connecting part (321) is separated into two parts centered on the fracture zone (P), and each part is bent upward in the direction in which flames and residues are ejected, so that the passage blocked by the housing connecting part (30) can be opened. Therefore, flames and residues can be discharged smoothly.

[0157]

[0158] Below, the fracture zone described above—that is, the region in which a fracture zone is formed that includes a material (second material) with relatively weak thermal durability—is described in detail.

[0159] FIG. 12 is a drawing for explaining the location of a fracture zone according to another embodiment of the present invention, FIG. 13 is a drawing for explaining the location of a fracture zone according to another embodiment of the present invention, and FIG. 14 is a drawing for explaining the location of a fracture zone according to another embodiment of the present invention.

[0160] Referring to FIG. 12, the fracture zone (P2) may be formed in the area adjacent to the contact portion (322) at the connection portion (321), more specifically at the boundary surface between the connection portion (321) and the contact portion (322). The contact portion (322) may be joined in close contact with the beading portion (21) of the battery housing, and the connection portion (321) may be suspended in the air without contacting other members. Therefore, when a thermal event occurs inside the battery cell, the temperature of the contact portion (322), which receives heat transfer from the beading portion (21), may rise faster and higher, and accordingly, if the fracture portion (P2) is formed at the boundary surface with the contact portion (322), it may melt at a faster rate. Furthermore, there may be a difference in the rate of temperature rise between the contact portion (322) and the connection portion (321), and as a result, thermal shock may occur at the boundary surface between the contact portion (322) and the connection portion (321). And, such thermal shock may further accelerate the failure of the fracture zone (P2). In addition, as previously explained, the contact portion (322) is welded to the beading portion (21), and during this welding process, thermal damage may accumulate at the boundary surface between the contact portion (322) and the connection portion (321). Therefore, if a fracture zone (P2) is formed at this part, that is, at the boundary surface, the failure of the fracture zone (P2) may be accelerated.

[0161]

[0162] As another embodiment, referring to FIG. 13, the fracture zone (P2) may be formed in the area adjacent to the support portion (31) in the connection portion (321), more specifically at the boundary surface between the body portion (311) and the contact portion (321). The body portion (311) may be in contact with the electrode assembly (10), and the connection portion (321) may be in a state of being suspended in the air without contact with other members. Therefore, when a thermal event occurs inside the battery cell, the temperature of the body portion (311) may rise faster and higher, and accordingly, if the fracture portion (P2) is positioned adjacent to the body portion (311), it may melt at a faster rate. Also, there may be a difference in the rate of temperature rise between the body portion (311) and the connection portion (321), and as a result, a thermal shock may occur at the boundary surface between the body portion (311) and the connection portion (321). Furthermore, such thermal shock can further accelerate the failure of the fracture zone (P2). Additionally, as previously explained, the body part can be welded to the electrode assembly (more specifically, the first non-reinforced part), and during this welding process, thermal damage may accumulate at the boundary surface between the body part (311) and the connection part (321). Therefore, if a fracture zone (P2) is formed at this part, i.e., the boundary surface, the failure of the fracture zone (P2) can be accelerated.

[0163]

[0164] Referring to FIG. 14 as another embodiment, the fracture zone (P2) may be formed to include at least a portion of the contact portion (322). Specifically, a beading portion (21) is formed in the battery housing (20), and the contact portion (322) may be coupled to the beading portion (21). The fracture zone (P2) may be formed to include a portion of the contact portion (322) or the entire contact portion (322). For example, as in FIG. 14, the entire contact portion (322) may be formed as the fracture zone (P2). If the fracture zone (P2) is in contact with the beading portion (21), it may be heated at a faster rate by the heat transferred from the beading portion (21) when a thermal event occurs, and thus the fracture zone (P2) may be broken faster.

[0165]

[0166] In the following, specific examples regarding the structure of a fracture zone including a material (second material) with relatively weak thermal durability will be described.

[0167] FIGS. 15 to 18 are partial diagrams illustrating the structure of a fracture zone according to another embodiment of the present invention.

[0168] Referring to FIG. 15, the fracture zone (P2a) is formed long in the width direction of the connecting part (321) and may include a material with lower thermal durability than the surrounding area. Specifically, the connecting part (321), which is the surrounding area, may be formed by including a first material, for example, copper, and the fracture zone (P2a) may be formed by including a second material, for example, zinc, which has lower thermal durability than the first material. Additionally, a plurality of through holes (h) may be formed through the fracture zone (P2a).

[0169] When a through hole is formed in the fracture zone (P2a) in this manner, as previously explained, a gas having turbulent characteristics passes through the through hole (h) and applies friction and shock waves, so the fracture of the fracture zone (P2a) can be accelerated.

[0170]

[0171] Referring to FIG. 16 as another embodiment of the fracture zone structure, the fracture zone (P2b) is formed to be elongated in the width direction of the connecting part (321). That is, the fracture zone (P2b) is formed to be elongated from one side of the connecting part (321) to the opposite side. In addition, a portion of the fracture zone (P2b) (A1) may be made of the same material as the other area of ​​the connecting part (321) excluding the fracture zone (P2b), such as copper, and the remaining area (A2) may be made of a second material having lower thermal durability than the first material, such as zinc. When the fracture zone (P2b) is configured in this way, the area (A2) made of the second material in the fracture zone (P2b) is damaged first, and then the remaining area can also be damaged at a rapid rate.

[0172] Specifically, based on the width direction of the connecting part (321), that is, the length direction of the fracture zone (P2b), an area (A2) made of the second material is formed on the outer region of the fracture zone (P2b), that is, on both edges, and an area (A1) made of the first material can be formed in the center of the fracture zone (P2b).

[0173] When the fracture zone (P2b) is configured in this way, when a thermal event occurs, the edges (A2) on both sides of the fracture zone (P2b) containing the second material may be damaged first. And, when the edges on both sides are damaged first in this way, the external force applied to the fracture zone (P2b) is concentrated in the center of the fracture zone (P2b), and accordingly, the center of the fracture zone (P2b) may also be damaged rapidly in a chain reaction.

[0174]

[0175] Further consideration in this regard is that under conditions where the connecting part (321) and the fracture zone (P2b) have a certain width, if the material of the fracture zone (P2b) is changed to a material different from that of the connecting part (321), namely a second material, the electrical characteristics of the entire current collector may deteriorate due to the difference between the first material and the second material. In other words, if a fracture zone (P2b) made of the second material is formed, the electrical characteristics may deteriorate compared to when the entire connecting part (321) is made of the first material. At this time, as the area (A2) made of the second material within the fracture part (P2b) becomes larger, the electrical characteristics may deteriorate even more. Therefore, it may be important to minimize the deterioration of electrical characteristics while simultaneously ensuring that the fracture zone breaks quickly.

[0176] From this perspective, forming only a portion of the fracture zone with the second material, rather than forming the entire fracture zone with the second material, can further reduce the degradation of electrical characteristics. At the same time, if the edge portion of the fracture zone (P2b) is damaged first, the central portion is damaged rapidly in a chain reaction; thus, the effect of causing the fracture zone (P2b) to be damaged quickly while minimizing the degradation of electrical characteristics, as intended above, can be expected.

[0177]

[0178] Referring to FIG. 17 as another embodiment of the fracture zone, the fracture zone (P2c) is formed long in the width direction of the connecting part (321). Then, based on the width direction of the connecting part (321), that is, the length direction of the fracture zone (P2c), an area (A2) made of the second material is formed in the center of the fracture zone (P2c), and an area (A1) made of the first material is formed in the outer area of ​​the fracture zone (P2c), that is, on both edges.

[0179] When the fracture zone (P2c) is configured in this manner, the central part of the fracture zone (P2c) may be damaged first upon the occurrence of a thermal event. Furthermore, if the central part of the fracture zone (P2c) is damaged first in this manner, the external force applied to the fracture zone (P2c) is concentrated on both edges of the fracture zone (P2c), and accordingly, the edges of the fracture zone (P2c) may also be damaged rapidly in a chain reaction. Moreover, as previously explained, the degradation of the electrical characteristics of the current collector can be reduced by forming only a portion of the fracture zone (P2c) with the second material.

[0180]

[0181] Referring to FIG. 18 as another embodiment of the fracture zone, the fracture zone (P2d) is formed long in the width direction of the connecting part (321). Then, based on the width direction of the connecting part (321), that is, the length direction of the fracture zone (P2d), a region (A1) made of the first material and a region (A2) made of the second material are alternately arranged.

[0182] When the fracture zone (P2d) is configured in this manner, upon the occurrence of a thermal event, the region (A2) made of the second material melts and breaks first, resulting in a hole being formed in the fracture zone (P2d). Then, as gas with turbulent characteristics flows through this hole, the remaining region, that is, the region made of the first material (A1), is also rapidly broken in a chain reaction. Furthermore, as previously explained, by forming only a portion of the fracture zone (P2d) with the second material, the degradation of the electrical characteristics of the current collector can be reduced.

[0183] In summary, as disclosed in FIGS. 16 to 18, a fracture zone is formed in the width direction of the connection part, and if a region made of the first material and a region made of the second material are formed together in this fracture zone, the purpose of the fracture zone, namely, to be quickly destroyed when a thermal event occurs, is satisfied, and at the same time, the degradation of the electrical characteristics of the current collector can be reduced.

[0184]

[0185] Meanwhile, although not shown in the drawing, the fracture zone may be configured such that its thickness is thinner than the surrounding area. For example, the fracture zone may be formed by creating a groove of a certain depth while extending in the width direction of the connection. In this case, the groove can be formed in one step using a cutting tool or notch forming equipment.

[0186] If the fracture zone is configured in this way, when a thermal event occurs, the connection may not bend as a whole due to the external force (pressure) transmitted to the connection, but rather be bent along the fracture zone line, and thus the fracture zone may be damaged at a rapid rate.

[0187] Furthermore, a fracture zone with such a structure does not require a complex forming process, and the connection can be formed by passing it through a cutting tool or notch forming equipment in a single pass. Therefore, the increase in manufacturing process time of the current collector caused by the formation of the fracture zone can be minimized.

[0188]

[0189] Meanwhile, the housing joint may further include a fracture acceleration member so that the fracture portion breaks faster when a thermal event occurs. FIG. 19 is a partial enlarged view of the housing joint according to another embodiment of the present invention, and FIG. 20 is a partial enlarged view of the housing joint according to another embodiment of the present invention.

[0190] Referring to FIG. 3 and FIG. 19 together, the housing coupling portion (32) according to the present embodiment may include a contact portion (322), a connecting portion (321), and a fracture acceleration portion (33). The contact portion (322) may be joined to the beading portion (21) by means such as welding. The connecting portion (321) may be formed extending from the support portion (31) to the contact portion (322). Additionally, a fracture zone (P) may be formed in the connecting portion (321). The fracture zone (P) is an area having lower strength than the surrounding area and may be implemented by the previously described methods, such as forming a notch line or a through hole, using different materials, or reducing the thickness.

[0191] The fracture acceleration section (33) is intended to concentrate heat, pressure, etc., into the fracture zone (P) when a thermal event occurs, thereby causing the fracture zone (P) to break faster. The fracture acceleration section (33) is formed by extending outward from the connecting section (321) and can be formed at a location adjacent to the fracture zone (P). More specifically, the connecting section (321) can be formed by extending from the supporting section (31) to the contact section (322) with a certain width. And, the fracture acceleration section (33) can be formed by extending outward from both ends of the connecting section. At this time, the fracture acceleration section (33) can be formed at a location adjacent to the area where the fracture zone (P) is formed, for example, below or above the boundary surface of the fracture zone (P), and can also be formed both above and below the fracture zone (P) as shown in FIG. 19.

[0192] At this time, if the fracture acceleration part (33) overlaps with the formed area of ​​the fracture zone (P), that is, for example, if the fracture acceleration part (33) is also formed on the side of the fracture zone (P), the fracture acceleration part (33) can actually make the strength of the fracture zone (P) stronger, so it is necessary to take note of this point.

[0193] When the fracture acceleration section (33) is provided in this manner, the connecting section (321) has a uniform width overall, but at the point where the fracture acceleration section (33) is formed, the width becomes substantially wider. Consequently, more external force (pressure and / or fluid flow) and heat are concentrated at the point where the fracture acceleration section (33) is formed, and this concentrated external force and heat can be transferred to the adjacent fracture zone (P). Therefore, the fracture of the fracture zone (P) can be accelerated.

[0194] Meanwhile, although not shown in the drawing, if the fracture zone (P2) exists at the boundary between the contact part (322) and the connection part (321) as in FIG. 12, the fracture acceleration part can be formed only on the lower side of the fracture zone (P2).

[0195]

[0196] Referring to FIG. 20 as another embodiment regarding the fracture acceleration part, a plurality of micro-holes (h2) may be formed through the fracture acceleration part (33A). Additionally, an uneven structure (n) may be formed around the perimeter of the fracture acceleration part (33A). Only one of the micro-holes (h2) and the uneven structure (n) may be formed, or both may be formed together.

[0197] Furthermore, when multiple micro-holes (h2) and / or uneven structures (n) are formed in this manner, turbulence occurs as high-pressure gas passes through the micro-holes (h2) and / or uneven structures (n). Consequently, friction between the micro-holes (h2) and / or uneven structures (n) and the gas increases, and the effect of increasing the magnitude of the external force (pressure) applied to the fracture acceleration part (33A) may occur. Additionally, vibration may occur as the fracture acceleration part (33A) shakes due to the gas passing through the micro-holes (h2) and / or uneven structures (n). Since this external force and vibration are transmitted to the fracture zone (P), the fracture of the fracture zone (P) can be further accelerated.

[0198]

[0199] Meanwhile, as illustrated in FIG. 4, a plurality of housing coupling parts (32) may be provided on the current collector (30), and a fracture zone (P) may be formed in all housing coupling parts (32), but alternatively, a fracture zone (P) may be formed only in some housing coupling parts (32). FIG. 21 is a plan view of a current collector coupled to a battery housing according to another embodiment of the present invention.

[0200] Since the current collector (30A) according to FIG. 21 is similar to the current collector (30) of the embodiment described with reference to FIG. 4, redundant descriptions of configurations that are substantially identical or similar to the previous embodiment will be omitted, and the following description will focus on the differences from the previous embodiment.

[0201] The current collector (30A) may have a support portion (31) and a housing coupling portion (32). The support portion (31) may have a body portion (311) and a plurality of tab coupling portions (312) that extend radially from the body portion (311), for example, four tab coupling portions (312).

[0202] The housing coupling portion (32) is provided in multiple numbers; for example, a housing coupling portion (32) may be provided between each tab coupling portion (312), so that a total of four housing coupling portions (32) may be provided. The housing coupling portion (32) may have a contact portion (322) and a connection portion (321). In addition, a fracture zone (P) may be formed in the connection portion (321) of the housing coupling portion. However, unlike the embodiment described above, the fracture zone (P) may be formed in only some of the four housing coupling portions (32), for example, in only one housing coupling portion (32). In addition, when a thermal event occurs, this fracture zone (P) may be damaged first.

[0203] Here, referring to FIG. 21, when looking at the entire housing coupling part (32), four housing coupling parts (32) are arranged radially from the support part (31). These four housing coupling parts (32) can be arranged symmetrically with respect to the support part (31), or more precisely, with respect to the center of the battery housing (20). On the other hand, if only the housing coupling part (32) formed with the fracture zone (P) is considered, since only one housing coupling part (32) with the fracture zone (P) is arranged, it does not form a symmetrical structure with respect to the support part (31), but rather has an asymmetrical structure.

[0204] If we briefly consider the internal state of the battery housing, the battery housing is cylindrical in shape and has a symmetrical form with respect to its center. Most of the remaining components, such as the electrode assembly and current collector, are also arranged symmetrically with respect to the center of the battery housing, which may be intended to improve the efficiency and uniformity of the cylindrical battery. Furthermore, because the interior of the battery cell is symmetrical with respect to its center in this way, the pressure inside the battery cell can be applied relatively uniformly throughout the entire interior of the cell in the event of a thermal event.

[0205] Meanwhile, when the battery cell is in a normal state, that is, when no thermal event occurs, a total of four housing joints (32) may form a symmetrical structure as previously mentioned. If a thermal event occurs in this state, one of the four symmetrical housing joints (32), that is, the housing joint (32) where the fracture zone (P) is formed, may be damaged first, and consequently, the symmetrical structure formed by the four housing joints (32) may be broken. Then, high-pressure gas and flames may be concentrated in the surrounding area of ​​the damaged housing joint (32), that is, the area marked Z in FIG. 21. In other words, high-pressure gas, flames, and residues may be concentrated in the area (Z) where the damaged housing joint (32) is located and discharged at a rapid speed.

[0206] Furthermore, when high-pressure gas is discharged to one side in this manner, the damaged connection part (321) is lifted upwards by shaking (i.e., vibration) due to the pressure, and the vibration and external force generated at this time are transmitted through the connection part (321) to an adjacent point connected to the connection part (321), for example, the area (S) where the beading part (21) and the contact part (322) are welded, or the point (S) where the tab connection part (312) and the electrode assembly (10) are welded. Then, due to the external force and vibration transmitted in this way, the welded part of the tab connection part (312) or the contact part (322) is rapidly damaged, and finally, the entire current collector (30) can be separated and detached from the battery housing.

[0207] That is, as in the present embodiment, if the housing coupling part (32) with the fracture zone (P) provided is arranged asymmetrically with respect to the support part, more precisely the center of the battery housing, then when a thermal event occurs, internal pressure or flames can be concentrated on one side of the battery housing, and through this, flames or residues can be quickly discharged to the outside.

[0208]

[0209] Meanwhile, regarding the aforementioned asymmetric structure, an additional example is provided. For example, assume that a total of six housing joints are provided, but fracture zones are formed in only two of them. Then, if the six housing joints are first arranged radially—that is, placed at the 12 o'clock, 2 o'clock, 4 o'clock, 6 o'clock, 8 o'clock, and 10 o'clock positions based on a clockwise direction—these six housing joints can be symmetrical with respect to the center. Now, if we consider only the housing joints with fracture zones separately, and the two housing joints with fracture zones are placed at 12 o'clock and 6 o'clock, then even when looking only at the housing joints with fracture zones, they are symmetrical with respect to the center. However, if the housing joints with fracture zones are placed adjacent to each other, for example at 12 o'clock and 2 o'clock, the housing joints with fracture zones can form an asymmetrical structure rather than a symmetrical one with respect to the battery housing. Furthermore, this arrangement can be varied depending on the number of housing joints.

[0210]

[0211] Referring to FIG. 3, a terminal (50) can be electrically connected to a second blank portion (12) of an electrode assembly (10) by penetrating the battery housing (20) on the opposite side of the opening of the battery housing (20). The terminal (50) can penetrate approximately the center of the lower surface of the battery housing (20). The terminal (50) can be electrically connected to the electrode assembly (10) by, for example, being coupled to a second current collector (60) coupled to the second blank portion (12) or by being coupled to a lead tab (not shown) coupled to the second blank portion (12). Thus, the terminal (50) has the same polarity as the second electrode of the electrode assembly (10) and can function as a second electrode terminal. If the second blank portion (12) is a positive tab, the terminal (50) can function as a positive terminal.

[0212] Considering the polarity and function of the terminal (50), the terminal (50) must be kept insulated from the battery housing (20) having opposite polarity. To this end, an insulating gasket (G2) may be applied between the terminal (50) and the battery housing (20). Alternatively, insulation may be achieved by coating a portion of the surface of the terminal (50) with an insulating material.

[0213] For the same reason, the second non-removable portion (12) and / or the second current collector (60) must remain insulated from the battery housing (20). To this end, an insulator (70) may be interposed between the second non-removable portion (12) and the battery housing (20) and / or between the second current collector (60) and the battery housing (20). When the insulator (70) is applied, the terminal (50) may pass through the insulator (70) for electrical connection with the second non-removable portion (12).

[0214]

[0215] Meanwhile, in the present invention, the outer surface (20a) of the closed portion located opposite the opening provided at the top of the battery housing (20) can function as a first electrode terminal. If the first open portion (11) is a negative electrode tab, the first electrode terminal may be a negative electrode terminal. The battery cell (1) according to the present invention has a structure in which a terminal (50) exposed on the lower surface located opposite the opening of the battery housing (20) can be used as a second electrode terminal, and the remaining area of ​​the lower surface of the battery housing (20), excluding the area occupied by the terminal (50) (including the area where the insulating gasket (G2) is exposed to the outside of the terminal (50) in the case where the insulating gasket (G2) is exposed on the outer surface (20a) of the closed portion), can be used as a first electrode terminal. Accordingly, the battery cell (1) according to the present invention can connect both positive and negative electrodes in one direction when electrically connecting a plurality of battery cells (1), thereby simplifying the electrical connection structure. In addition, the battery cell (1) according to the present invention has a structure in which most of the lower surface located opposite the opening of the battery housing (20) can be used as an electrode terminal, thus having the advantage of being able to secure a sufficient area for welding components for electrical connection.

[0216]

[0217] Referring to FIG. 22, a battery pack (3) according to one embodiment of the present invention comprises a battery assembly in which a plurality of battery cells (1) according to one embodiment of the present invention as described above are electrically connected, and a pack housing (2) that accommodates the same. In the drawings of the present invention, components such as a busbar for electrical connection, a cooling unit, and a power terminal are omitted for convenience of drawing.

[0218] Referring to FIG. 23, a vehicle (5) according to one embodiment of the present invention may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, and includes a battery pack (3) according to one embodiment of the present invention. The vehicle (5) includes a four-wheeled vehicle and a two-wheeled vehicle. The vehicle (5) operates by receiving power from the battery pack (3) according to one embodiment of the present invention.

[0219]

[0220] 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.

[0221]

[0222] [Explanation of the symbol]

[0223] 5: Cars

[0224] 3: Battery Pack

[0225] 2: Pack Housing

[0226] 1: Battery cell

[0227]

[0228] 10: Electrode assembly

[0229] 11: 1st Department of Indefinite Use

[0230] 12: 2nd Department of Indefinite Use

[0231] H1: Winding hole

[0232]

[0233] 20: Battery housing

[0234] 20a: External surface of the closure

[0235] 21: Bidding Department

[0236] 22: Climbing Department

[0237]

[0238] 30: The whole house (the first whole house)

[0239] H2: Entire house hall

[0240] 31: Support

[0241] 311...Body

[0242] 312...Tab joint

[0243] 32: Housing joint

[0244] 321...connection part

[0245] 322...contact part

[0246] P : Fracture zone

[0247]

[0248] 40: Housing cover

[0249] 41: Venting Department

[0250] G1: Sealing gasket

[0251]

[0252] 50: Terminal

[0253] G2: Insulating gasket

[0254] 60: The entire second house

[0255] 70: Insulator

Claims

1. An electrode assembly in which a first electrode and a second electrode and a separator interposed between them are wound around a winding axis to define a core and an outer surface, wherein the first electrode comprises a first uncoated portion in which an active material layer is not coated along the winding direction; A battery housing having an opening formed on one side and accommodating the electrode assembly inside through the opening; A current collector disposed on one side of the electrode assembly and electrically connecting the first non-removable portion and the battery housing; and A housing cover covering the above-mentioned opening; is included, The entire house mentioned above is, A support member positioned facing the first blank portion of the electrode assembly and electrically connected to the first blank portion, and It includes a plurality of housing coupling parts that are formed extending from the above support member, with one end coupled to the battery housing and electrically connected to the battery housing, A battery cell characterized in that at least one of the plurality of housing joints has a fracture zone formed therein having a lower strength than the surrounding area.

2. In Paragraph 1, A battery cell characterized by having a plurality of through holes formed through the fracture zone.

3. In Paragraph 2, The above housing coupling portion includes a contact portion coupled to the battery housing and a connecting portion connecting the contact portion and the support portion, and A battery cell characterized in that the above fracture zone is formed in the above connection part.

4. In Paragraph 3, A battery cell characterized in that the above-mentioned fracture zone is provided in an area adjacent to the above-mentioned contact portion at the above-mentioned connection portion.

5. In Paragraph 3, A battery cell characterized in that the above-mentioned fracture zone is provided in an area adjacent to the above-mentioned support at the above-mentioned connection part.

6. In Paragraph 2, A battery cell characterized in that the plurality of through holes include through holes having different sizes or shapes.

7. In Paragraph 2, A battery cell characterized in that the through holes are formed more on the outer side of the fracture zone than on the central side of the fracture zone.

8. In Paragraph 2, A battery cell characterized in that the through holes are formed more in the center of the fracture zone than on the outer side of the fracture zone.

9. In Paragraph 1, A battery cell characterized in that the fracture zone comprises a second material having lower thermal resistance compared to a first material constituting a surrounding area.

10. In Paragraph 9, A battery cell characterized in that the above-mentioned second material includes zinc.

11. In Paragraph 9, A battery cell characterized by having a plurality of through holes formed in the fracture zone.

12. In Paragraph 9, The housing coupling portion includes a contact portion coupled to the battery housing and a connecting portion connecting the contact portion and the support portion, and A battery cell characterized in that the fracture zone is formed in the width direction of the connection portion and has a region made of the first material and a region made of the second material.

13. In Paragraph 12, A battery cell characterized in that the area formed by the second material is located at both edges based on the width direction of the connection part.

14. In Paragraph 12, A battery cell characterized in that the region formed by the second material is located in the center based on the width direction of the connection part.

15. In Paragraph 12, A battery cell characterized by having a structure in which a region formed of the first material and a region formed of the second material are alternately arranged.

16. In Paragraph 1, A battery cell characterized by having a fracture acceleration member provided in the housing coupling portion, which is located adjacent to the fracture zone and accelerates the fracture of the fracture zone by concentrating heat or pressure generated inside the battery housing into the fracture zone.

17. In Paragraph 16, The housing coupling portion includes a contact portion coupled to the battery housing and a connecting portion connecting the contact portion and the support portion, and The above fracture zone is formed in the above connection part, and A battery cell characterized in that the fracture acceleration part is located adjacent to the fracture zone and extends outwardly from the connection part.

18. In Paragraph 17, A battery cell characterized by having a plurality of micro-holes formed through the fracture acceleration part.

19. In Paragraph 17, A battery cell characterized by having an uneven structure formed along the circumference of the fracture acceleration section.

20. In Paragraph 1, The plurality of housing coupling parts are arranged radially around the support part, and A battery cell characterized in that the housing joint portion having the above-mentioned fracture zone is arranged asymmetrically around the support portion.

21. A battery pack characterized by comprising at least one battery cell described in any one of claims 1 to 20.

22. An automobile characterized by comprising at least one battery pack as described in claim 21.

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