Lithium secondary battery

Abstract

The invention relates to a lithium secondary cell. This lithium secondary cell may consist of a cell, an electrode assembly and electrolyte contained within the cell, and a lid plate constructed to seal the cell. The cell may consist of a first end and a second end opposite the first end. The lithium secondary cell is constructed such that, if the internal pressure of the cell is 21 kgf / cm² or greater, at least part of the cell assembly is discharged through the first end of the cell. After part of the cell assembly has been discharged through the first end of the cell, the distance from one end of the electrode assembly furthest from the cell to the second end of the cell is at least 1.25 times the distance between the first and second ends of the cell.

Description

lithium secondary battery

[0001] [Cross-reference to related applications]

[0002] This application claims priority to Korean Patent Application No. 10-2023-0189919, filed December 22, 2023, and Korean Patent Application No. 10-2024-0169074, filed November 22, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a lithium secondary battery. In particular, the present invention relates to a lithium secondary battery having a structure in which an electrode assembly is housed in a battery can.

[0004] Recent advancements in electric vehicle technology have led to a growing demand for high-capacity batteries, necessitating the development of large, bulky cylindrical batteries. These batteries are attracting attention as an energy source that can significantly reduce fossil fuel use and improve environmental friendliness and energy efficiency, as they produce no byproducts when consumed.

[0005] In the case of conventionally used small cylindrical batteries, such as those with form factors of 1865 or 2170, resistance and heat generation did not significantly impact battery performance due to their small capacities. However, applying the specifications of conventional small cylindrical batteries to large cylindrical batteries could lead to serious safety issues.

[0006] As the size of a battery increases, the amount of heat and gas generated within it also increases. This heat and gas can increase the temperature and pressure inside the battery, potentially leading to ignition or explosion. To prevent this, the heat and gas inside the battery must be properly discharged to the outside. To achieve this, the cross-sectional area of ​​the battery, which serves as a passage for heat dissipation to the outside, must increase in proportion to the increase in volume. However, because the increase in cross-sectional area typically does not keep pace with the increase in volume, larger batteries lead to increased internal heat generation, which increases the risk of explosion and causes problems such as reduced output. Furthermore, when rapid charging is performed at high voltage, a large amount of heat is generated around the electrode tabs in a short period of time, which can lead to battery ignition.

[0007] To prevent such risks of fire or explosion, prior art has incorporated safety devices into secondary batteries. One example is the vent, commonly found in cylindrical secondary batteries. According to prior art, when the internal pressure of a secondary battery increases, the vent moves upward, and a portion of the vent ruptures, creating a path for gas to escape. This allows gas within the secondary battery to escape to the outside, thereby preventing the risk of explosion.

[0008] However, even when such a vent is opened, the side of the battery can ruptures. When cylindrical lithium secondary batteries are used in automobiles, they are applied to the vehicle in the form of a battery pack comprising multiple cylindrical lithium secondary batteries. Such rupture of the side of the battery can can cause continuous fires to occur in other surrounding unit cells within the battery pack.

[0009] The present invention relates to a battery having a large volume and high safety while having a high capacity by reducing or preventing the problem of the side of a battery can bursting when the internal pressure of the battery can increases in a lithium secondary battery.

[0010] Furthermore, aspects of the present invention can reduce or prevent the problem of rupture of the side portion of the battery can, thereby reducing the possibility of a single battery in a battery pack containing multiple batteries affecting other batteries nearby. This can also significantly improve the safety of the battery pack and the vehicle containing the battery.

[0011] Accordingly, the present invention relates to a lithium secondary battery, a battery pack, and a vehicle with improved safety.

[0012] One aspect of the present invention is

[0013] A lithium secondary battery comprising a battery can, an electrode assembly and an electrolyte housed inside the battery can, and a cap plate configured to seal the battery can,

[0014] The battery can includes a first end and a second end opposite to the first end,

[0015] The above lithium secondary battery has an internal pressure of 21 kgf / cm of the battery can. 2 A lithium secondary battery is provided, wherein at least a portion of the electrode assembly is configured to be discharged through a first end of the battery can when the electrode assembly is discharged through the first end of the battery can, and a distance from an end of the electrode assembly located furthest from the battery can to a second end of the battery can after the electrode assembly is discharged through the first end of the battery can is at least 1.25 times the distance between the first end and the second end of the battery can.

[0016] According to one aspect, the lithium secondary battery is configured such that a portion of the electrode assembly is discharged through the first end of the battery can without or before thermal runaway of the lithium secondary battery; or without or before rupture of the side surface of the battery can.

[0017] According to one aspect, the first end of the battery can includes a vent portion, or the cap plate is fixed to the first end of the battery can, and the cap plate includes a vent portion. Here, the lithium secondary battery is configured such that a portion of the electrode assembly can be discharged through the first end of the battery can after a structure fixing the cap plate to the first end of the battery can is broken or after the vent portion is ruptured.

[0018] According to one aspect, the cap plate includes a vent portion, and the vent portion has an internal pressure of 21 kgf / cm 2 It is configured to burst when the pressure is above 25 kgf / cm. According to one aspect, the vent part has an internal pressure of 25 kgf / cm. 2 Exceeding 29 kgf / cm 2 It can be configured to burst when less than.

[0019] According to one aspect, the ratio of the maximum width in the cross section in the vertical direction of the winding axis of the electrode assembly to the maximum width in the cross section in the vertical direction of the winding axis of the battery can is less than 1.

[0020] According to one aspect, the lithium secondary battery includes a first current collecting plate provided between a first end of the battery can and the electrode assembly.

[0021] According to one aspect, the first collector plate may have a battery can coupling portion having a tapered structure.

[0022] According to one aspect, the flame exhaust area may be 30% to 50% based on the total opening area of ​​the first end of the battery can.

[0023] According to one aspect, the form factor ratio (height to diameter ratio) of the lithium secondary battery may be 0.4 or greater. For example, the lithium secondary battery may be a 46110 cell, a 4875 cell, a 48110 cell, a 4880 cell, a 4680 cell, or a 4695 cell.

[0024] According to one aspect, the electrode assembly is cylindrical.

[0025] According to one aspect, the thickness of the side of the battery can is 0.1 mm to 0.4 mm. According to one aspect, the electrode assembly is a jelly-roll type electrode assembly in which a positive electrode plate and a negative electrode plate are wound together with a separator interposed between the positive electrode plate and the negative electrode plate, and after a part of the electrode assembly is discharged through the first end of the battery can, the electrode assembly has a spiral structure.

[0026] According to one aspect, a sealing tape comprising polypropylene or polyimide is attached to the outermost end of the electrode assembly.

[0027] According to one aspect, the positive and negative electrode plates each include a non-conductive portion on which an active material layer is not formed, and at least a portion of the non-conductive portion of the positive or negative electrode plate defines an electrode tab.

[0028] According to one aspect, the positive electrode plate uncoated portion and the negative electrode plate uncoated portion are formed along the direction in which the electrode assembly is wound on one end of the positive electrode plate and the negative electrode plate, respectively, a first current collecting plate is coupled to the positive electrode uncoated portion, a second current collecting plate is coupled to the negative electrode uncoated portion, and the first current collecting plate and the second current collecting plate are each connected to an electrode terminal.

[0029] According to one aspect, the positive electrode plate non-conductive portion and the negative electrode plate non-conductive portion are processed into a plurality of independently bendable segments, and at least some of the plurality of independently bendable segments are bent toward the winding center of the electrode assembly.

[0030] According to one aspect, at least some of the independently bendable plurality of segments are overlapped on the upper part of the electrode assembly or the lower part of the electrode assembly, and the first collector plate and the second collector plate are respectively coupled on the overlapped plurality of segments.

[0031] One aspect of the present invention provides a lithium secondary battery comprising a battery can, an electrode assembly and an electrolyte housed inside the battery can, and a cap plate configured to seal the battery can, wherein the battery can includes a first end and a second end opposite the first end, and includes a first current collecting plate provided between the first end of the battery can and the electrode assembly, and the first current collecting plate includes a battery can joint having a tapered structure.

[0032] According to one aspect, the tapered structure is 0.7 or less of the minimum width (w4) existing close to the center side of the battery can with respect to the maximum width (w3) in the direction perpendicular to the diameter passing through the center axis of the battery can.

[0033] One aspect of the present invention provides a lithium secondary battery including a battery can, an electrode assembly and an electrolyte housed inside the battery can, and a cap plate configured to seal the battery can, wherein the battery can includes a first end and a second end opposite the first end, and includes a first current collecting plate provided between the first end of the battery can and the electrode assembly, and a flame exhaust area is 30% to 50% based on the total opening area of ​​the first end of the battery can.

[0034] According to one aspect, the flame exhaust area is 35% to 50% based on the total opening area of ​​the first end of the battery can.

[0035] One aspect of the present invention provides a lithium secondary battery including a battery can, an electrode assembly and an electrolyte housed inside the battery can, and a cap plate configured to seal the battery can, wherein the battery can includes a first end and a second end opposite the first end, and includes a first current collecting plate provided between the first end of the battery can and the electrode assembly, and wherein the first current collecting plate has a thickness of 0.25 mm or less.

[0036] One aspect of the present invention provides a lithium secondary battery comprising a battery can, an electrode assembly and an electrolyte housed inside the battery can, and a cap plate configured to seal the battery can, wherein a sealing tape comprising polypropylene or polyimide is attached to an outermost end of the electrode assembly.

[0037] One aspect of the present invention provides a lithium secondary battery comprising a battery can, an electrode assembly and an electrolyte housed inside the battery can, and a cap plate configured to seal the battery can, wherein a ratio of a maximum width (w2) of the electrode assembly to a maximum width (w1) of the battery can is less than 1.

[0038] According to one aspect, the ratio of the maximum width (w2) of the electrode assembly to the maximum width (w1) of the battery can is 0.97 or less.

[0039] One aspect of the present invention provides a battery pack including a lithium secondary battery according to the aforementioned aspects.

[0040] One aspect of the present invention provides an electric vehicle including the battery pack as a power source.

[0041] A lithium secondary battery according to aspects of the present invention can prevent rupture of a side portion of a battery can due to an increase in internal pressure within the battery can or concentration of flames on vulnerable components within the battery can prior to rupture of the battery can. Specifically, by configuring the electrode assembly to be ejected through one end of the battery can without or before rupture of the side portion of the battery can due to the increased pressure within the battery can, rupture of the side portion of the battery can can be prevented. This can reduce the possibility that a single battery in a battery pack including multiple batteries will affect the surrounding batteries. This can prevent a chain reaction of fire among the batteries. Furthermore, by configuring the electrode assembly to be ejected outside the battery can without or before occurrence of a flame within the battery can, concentration of flames on vulnerable components within the battery can can be prevented.

[0042] This provides a lithium secondary battery with improved safety, as well as a battery pack and vehicle including the same. Furthermore, improving battery safety can ease other safety measures. For example, by making the previously thick battery can relatively thinner to improve safety, cost savings and improved processability are expected.

[0043] The following drawings, attached to this specification, illustrate aspects of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concepts of the present invention. Therefore, the present invention should not be construed as being limited to the matters described in these drawings.

[0044] Figure 1a illustrates a vertical cross-sectional structure of a lithium secondary battery according to one aspect of the present invention.

[0045] Figure 1b illustrates a vertical cross-sectional structure of a lithium secondary battery according to one aspect of the present invention.

[0046] FIG. 2 illustrates a structure after the electrode assembly is discharged through the first end of the battery can, according to one aspect of the present invention.

[0047] FIG. 3 is a drawing illustrating a state before winding of an electrode assembly according to one aspect of the present invention.

[0048] FIG. 4 is a drawing illustrating a state after winding of an electrode assembly according to one aspect of the present invention.

[0049] FIG. 5 illustrates a vertical cross-section of the winding axis of an electrode assembly according to one aspect of the present invention.

[0050] FIG. 6 illustrates a sealing tape attached to an outer side of an electrode assembly according to one aspect of the present invention.

[0051] FIG. 7 illustrates a tapered structure of a battery can joint of a first current collecting plate according to one aspect of the present invention.

[0052] Figures 8 to 10 illustrate the structure of a first collector plate according to one aspect of the present invention.

[0053] FIG. 9 illustrates the structure of a first collector plate according to one aspect of the present invention.

[0054] FIG. 10 illustrates the structure of a first collector plate according to one aspect of the present invention.

[0055] Figure 11 is a drawing illustrating an area (A) from which flames can be emitted at the first end of the battery can.

[0056] Figure 12 is a cross-sectional drawing of an electrode plate (positive plate or negative plate) according to one aspect of the present invention.

[0057] FIG. 13 is a drawing showing a schematic configuration of a battery pack including batteries according to one aspect of the present invention.

[0058] FIG. 14 is a schematic diagram showing the configuration of a vehicle including a battery pack according to one aspect of the present invention.

[0059] Figure 15 illustrates the structure of the current collecting plate used in the experimental example.

[0060] Figure 16 illustrates the structure of the current collecting plate used in the experimental example.

[0061] Figure 17 is a photograph of an electrode being discharged from the center of an electrode assembly according to an experimental example.

[0062] Hereinafter, aspects of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Rather, they should be construed with meanings and concepts consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of a term to best explain his or her invention. Accordingly, the aspects described in this specification and the configurations depicted in the drawings are merely preferred aspects for explaining the technical aspects of the present invention and are not intended to be limited thereto. It should be understood that various equivalents and modifications may exist as of the time of this application.

[0063] Additionally, to facilitate understanding of the invention, the attached drawings are not drawn to scale and the dimensions of some components may be exaggerated. Furthermore, identical components may be assigned the same reference numbers in different drawings.

[0064] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0065] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0066] Any configuration being placed "on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with a surface such as an upper surface or lower surface of said component, and that other configurations may intervene between said component and any configuration placed on (or below) said component.

[0067] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0068] Throughout the specification, when we refer to "A and / or B," this means A, B, or A and B, unless otherwise stated. Also, when we refer to "C to D," this means C or more and D or less, unless otherwise stated.

[0069] For convenience of explanation, the direction along the longitudinal direction of the winding axis of the electrode assembly wound in the jelly-roll type is referred to as the axial direction (Y) in this specification. In addition, the direction surrounding the winding axis is referred to as the circumferential direction or the peripheral direction (X). In addition, the direction approaching or away from the winding axis is referred to as the radial direction. Among these, the direction approaching the winding axis is referred to as the centripetal direction, and the direction away from the winding axis is referred to as the centrifugal direction.

[0070] As used herein, the singular forms of words include the plural unless the context clearly dictates otherwise. The plural forms include the singular, and vice versa. Thus, references to "a," "an," and "the" generally include the plural forms of each term. For example, although the specification may be described using terms such as "a" layer, "a" substrate, "a" cell, etc., the specification may also be used to include two or more of these components, or combinations thereof, and other components.

[0071] The term "about" is intended to include the indicated value and a range above and below that value.

[0072] The words "comprise," "include," and "comprising" are to be construed inclusively, not exclusively. Similarly, the terms "include," "comprising," and "or" are to be construed inclusively, unless the context clearly prohibits such construction. A description of an embodiment defined using the term "comprising" is also a description of an embodiment "consisting essentially of" and "consisting of" the recited components. The phrase "consisting of" excludes any unspecified element, step, or ingredient.

[0073] As used herein, the term "a combination thereof" in a Markush expression means a combination or mixture of one or more elements selected from the group of elements described in the Markush expression, and implies the presence of one or more elements selected from said group. The term "a combination thereof" includes all possible combinations of the elements to which the term refers.

[0074] The term "between" as used herein includes endpoints.

[0075] Additionally, any numerical range mentioned herein should be understood to include all integers, whole numbers, or fractions within that range. Furthermore, any numerical range mentioned herein is intended to include all subranges subsumed therein, and such numerical ranges should be construed to support claims to any number or subset of numbers within that range. For example, a description of 1 to 10 should be construed to support ranges of 1 to 8, 3 to 7, 1 to 9, 3.6 to 4.6, 3.5 to 9.9, etc. When a range is given, all endpoints of that range and / or numbers within that range can be combined with the range of the present disclosure.

[0076] As used herein, the terms “including,” “for example,” “such as,” and similar terms mean “including / for example / such as but not limited to.”

[0077] The term "example" as used herein, especially when followed by a list of terms, is intended to be illustrative only and should not be construed as exclusive or comprehensive. Any implementation described herein may be combined with any other implementation described herein, unless expressly indicated otherwise.

[0078] The terms "vent portion" and "rupture notch" used herein are interchangeable. The word "vent" in the term "vent portion" has the same meaning as the word "rupture" in the term "rupture notch." Figures 1a and 1b each illustrate a vertical cross-sectional structure of a lithium secondary battery (1) according to one aspect of the present invention.

[0079] The lithium secondary battery (1) of FIG. 1A or 1B includes a battery can (20), an electrode assembly (10), an electrolyte (not shown), and a cap plate (40). The battery can (20) has a first end (E1) and a second end (E2) opposite to the first end (E1). In the present specification, the two opposite ends of the battery can (20) are referred to as the first end (E1) and the second end (E2), and a portion connecting the first end (E1) and the second end (E2) and surrounding the electrode assembly is referred to as a side portion of the battery can (20). When the above electrode assembly (10) is of the jelly-roll type, the two ends of the battery can (20) in the axial direction (Y) of the winding axis are the first end (E1) and the second end (E2), and the part of the battery can that surrounds the electrode assembly in the circumferential direction (X) of the winding axis is called the side part of the battery can.

[0080] At least one of the first end (E1) and the second end (E2) includes an opening. Either the first end (E1) or the second end (E2) may include an opening. According to some aspects of the present invention, both the first end (E1) and the second end (E2) may include an opening. The electrode assembly (10) and the electrolyte can be accommodated in the battery can (20) through the opening included in at least one of the first end (E1) and the second end (E2). After the electrode assembly (10) and the electrolyte are accommodated in the battery can (20), at least one opening of the first end (E1) and the second end (E2) can be closed by the cap plate (40). Fig. 1a is an example in which the first end (E1) of the battery can (20) is provided with an opening and a cap plate (40). Figure 1b is an example in which an opening and a cap plate (40) are provided at the second end (E2) of the battery can (20).

[0081] FIG. 1a and FIG. 1b are examples of cylindrical batteries (1), but the present invention is not limited by the shape of the battery and can be applied to batteries of other shapes, such as square batteries.

[0082] Referring to Fig. 1a, the battery (1) may further include one or more terminals (50), a sealing gasket (G1), an insulating gasket (G2), a current collecting plate (30, P), or an insulator (S). Referring to Fig. 1b, the battery (1) may further include one or more current collecting plates (30, P), an insulator (S), or a lead (45).

[0083] If necessary, a beading portion (21) and a crimping portion (22) may be provided on the upper end of the battery can (20) as a structure for fixing the cap plate (40) to the first end (E1) or the second end (E2) of the battery can (20). The beading portion (21) may be formed by pressing the outer circumference of the battery can (20) toward the winding central axis. The beading portion (21) prevents the electrode assembly (10) accommodated inside the battery can (20) from coming out through the opening of the battery can (20) during storage or normal charging and discharging of the lithium secondary battery, and may function as a support portion on which the cap plate (40) is seated.

[0084] The above-mentioned crimping portion (22) can be formed on the upper portion of the beading portion (21), and has an extended and bent shape to surround the outer surface of the cap plate (40) placed on the beading portion (21) and a portion of the upper surface of the cap plate (40).

[0085] The cap plate (40) is for sealing the open end of the battery can (20), for example, the first end (E1) or the second end (E2). The cap plate (40) may include a sealing gasket (G1) that provides airtightness between the cap plate (40) and the battery can (20). The gasket (G1) may have insulating properties. Referring to FIG. 1B, the cap plate (40) may further include a connecting plate (42c) that is electrically and mechanically coupled to the cap plate (40). For example, the cap plate (40) may be pressed onto a beading portion (21) formed on the battery can (20) and fixed by a crimping portion (22). A sealing gasket (G1) may be interposed between the cap plate (40) and the crimping portion (22) to ensure airtightness of the battery can (20) and to electrically insulate between the battery can (20) and the cap plate (40).

[0086] The material and structure of the cap plate (40) are not particularly limited as long as it can cover the opening of the first end (E1) or the second end (E2) of the battery can (20).

[0087] When the cap plate (40) is made of a metal material having electrical conductivity, the cap plate (40) can be electrically connected to the positive or negative electrode plate of the electrode assembly (10). In this respect, the cap plate (40) can be electrically insulated from the battery can (20) through a sealing gasket (G1). In this case, the cap plate (40) can function as a positive or negative terminal of the lithium secondary battery. Referring to Fig. 1b, the cap plate (40) can have a protrusion (42a) formed to protrude upward from its winding center (C). When the protrusion comes into contact with an external power source, current can be applied from the external power source. The protrusion may be exposed to the outside of the lithium secondary battery to come into contact with the external power source, and the degree of protrusion may be designed as needed. For example, it may be made to protrude only to a position corresponding to the end of the battery can (the first end, E1), as in Fig. 1a, or it may be made to protrude further out than the end of the battery can (the second end, E2), as in Fig. 1b.

[0088] However, it is not essential that the cap plate (40) functions as a current passage. In other words, the cap plate (40) may be composed of an electrically non-conductive material. Therefore, as long as the battery can (20) and the cap plate (40) can be firmly fixed through welding or the application of another component, and the sealing of the opening of the battery can (20) can be secured, the application of the aforementioned sealing gasket (G1) is not essential.

[0089] Meanwhile, the battery (1) according to the present invention may further include a current collecting plate (30, P), if necessary. Specifically, the battery (1) may include a first current collecting plate (30) provided between a first end (E1) of the battery can (20) and the electrode assembly (10) and / or a second current collecting plate (P) provided between a second end (E2) of the battery can (20) and the electrode assembly (10). As shown in Fig. 1a, the current collecting plate (first current collecting plate, 30) may be in direct electrical contact with the battery can (30), or as shown in Fig. 1b, the current collecting plate (second current collecting plate, P) may be connected to a lead (45). The lead (45) may extend upward from the electrode assembly (10) and be coupled to a connecting plate (42c) or directly coupled to a lower surface of the cap plate (40). The coupling of the lead (45) and other components may be accomplished by welding. Preferably, the current collecting plate (second current collecting plate, P) may be formed integrally with the lead (45). In this case, the lead (45) may have a long plate shape extending outward from the center of the current collecting plate (second current collecting plate, P).

[0090] Fig. 2 illustrates the structure of the electrode assembly (10) after the electrode assembly (10) is discharged through the first end (E1) of the battery can (20) due to an increase in the internal pressure of the battery can (20). A distance (t1) is a distance from the end (E0) of the electrode assembly (10) located furthest from the battery can (20) to the second end (E2) of the battery can (20). A distance (t2) is a distance between the first end (E1) and the second end (E2) of the battery can (20). The distance (t1) is at least 1.25 times, at least 1.27 times, at least 1.275 times, at least 1.3 times, at least 1.35 times, at least 1.4 times, at least 1.45 times, at least 1.5 times, at least 1.55 times, at least 1.6 times, at least 1.65 times, or at least 1.7 times the distance (t2). The distance (t1) may be at most 3 times, at most 2.9 times, at most 2.8 times, at most 2.7 times, at most 2.6 times, or at most 2.5 times the distance (t2). For example, the distance (t1) may be 1.25 to 3 times the distance (t2), or may be another range formed from a combination of the endpoints listed above.

[0091] The increase in internal pressure of the battery can may be caused by one or more of the following: overcharging, a defect in at least one component of the battery, an abnormal chemical reaction, an abnormal physical deformation, an external or internal shock to the battery, an abnormal temperature increase, etc. Although the above factors do not always cause an increase in internal pressure of the battery can, they may increase the possibility of such an increase.

[0092] The range of the ratio of the distance (t1) to the distance (t2) means that the electrode assembly (10) is ejected with a strong force through the first end of the battery can (20). Accordingly, when the electrode assembly (10) is ejected, only the first end (E1) of the battery can (20) or the cap plate (40) coupled to the first end (E1) is damaged, and other parts other than the first end (E1) or the cap plate (40) coupled to the first end (E1), such as the side part of the battery can, are less likely to be damaged. Accordingly, the possibility of chain ignition of batteries in a battery pack including a plurality of batteries according to the present invention can be prevented or reduced.

[0093] By the above-described operating principle, in a lithium secondary battery according to one aspect of the present invention, the electrode assembly can be discharged through the first end of the battery can without or before thermal runaway of the battery can, or without or before lateral rupture of the battery can.

[0094] In this specification, thermal runaway of the battery can refers to a phenomenon in which the temperature rises due to thermal factors, chemical or physical shocks inside and / or outside the battery, leading to a fire. Rupture of the side of the battery can refers to a case in which the battery can is torn, a pin hole is created, or melting occurs in a part of the battery can other than the first and second ends of the battery can, i.e., a part connecting the first and second ends, so that the pressure inside the battery can is released through the side of the battery can. The crimping portion and the beading portion may also be understood to be included in the side of the battery can.

[0095] In a lithium secondary battery according to one aspect of the present invention, since at least a portion of the electrode assembly is ejected with a strong force through the first end of the battery can when the pressure inside the battery can increases, a portion other than the first end of the battery can, i.e., a side of the battery can, is not damaged. In addition, in a lithium secondary battery according to one aspect of the present invention, since the electrode assembly is ejected out of the battery can within a very short time by the strong pressure, thermal runaway does not occur inside the battery can before a certain portion of the electrode assembly is ejected out of the battery can.

[0096] For example, the electrode assembly being discharged through the first end of the battery can due to an increase in the internal pressure of the battery can may occur under conditions of overcharging a lithium secondary battery by repeatedly charging and discharging at a rate of 1.5C to 2C, for example, at a rate of 1.7C.

[0097] According to one example, the electrode assembly is a jelly-roll type in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive and negative electrode plates are wound in one direction. Fig. 3 is a drawing showing the state of the electrode assembly (10) before winding, and Fig. 4 is a drawing showing the state of the electrode assembly (10) after winding.

[0098] As shown in FIG. 3, the electrode assembly (10) may have a structure in which a separator (212), a positive electrode plate (210), a separator (212), and a negative electrode plate (211) are sequentially laminated at least once. This laminate is wound in the X direction to form a jelly-roll type electrode assembly. When such a jelly-roll type electrode assembly (10) is discharged through the first end (E1) of the battery can (20), a portion of the electrode assembly arranged closer to the winding center (C) is discharged further from the battery can (20), thereby having a spiral structure as shown in FIG. 2.

[0099] Referring again to FIGS. 1A and 1B, the first end (E1) of the battery can (20) or the cap plate (40) provided at the first end (E1) includes a vent portion (41, 201).

[0100] FIG. 1A illustrates a structure in which a cap plate (40) provided at a first end (E1) of the battery can (20) has a vent portion (41). The cap plate (40) is fixed to the first end (E1) of the battery can (20), and the cap plate (40) may include a vent portion (41). In this aspect, the electrode assembly (10) may be discharged through the first end (E1) of the battery can (20) through breakage of the structure fixing the cap plate (40) to the first end (E1) of the battery can (20) or through breakage of the vent portion (41).

[0101] Fig. 1b illustrates a structure having a vent portion (201) at a first end (E1) of the battery can (20). The battery of Fig. 1b has an opening at a second end (E2) of the battery can, and a cap plate (40) is provided at the second end (E2). At this time, the electrode assembly (10) can be discharged through the first end (E1) of the battery can (20) by breaking the vent portion (201).

[0102] The above vent portion (41, 201) is formed on a portion of the cap plate (40) or the battery can (20) and corresponds to a structurally weaker region than the surrounding region so that it can be easily broken when internal pressure is applied. The above vent portion (41, 201) may be, for example, a region having a thinner thickness compared to the surrounding region. To achieve a thinner thickness, the above vent portion (41, 201) may include a notch.

[0103] According to one aspect, the internal pressure at which the vent part ruptures is 21 kgf / cm 2 Above, 21.5 kgf / cm 2 Above, 22 kgf / cm2 Above, 22.5 kgf / cm 2 Above, 23 kgf / cm 2 Above, 23.5 kgf / cm 2 Above, 24 kgf / cm 2 Above, 24.5 kgf / cm 2 Above, 25kgf / cm 2 Above, 25 kgf / cm 2 Exceeded, 25.5 kgf / cm 2 Above, 26 kgf / cm 2 Above, 26.5 kgf / cm 2 or more than 27 kgf / cm 2 It may be. According to one aspect, the internal pressure at which the vent part ruptures may be a pressure equal to or less than the pressure at which the cap plate is separated from the battery can. For example, when the battery can includes a means for fixing the cap plate, such as a crimping part, the internal pressure at which the vent part ruptures may be a pressure equal to or less than the pressure at which the crimping part is uncrimped. In another example, when the cap plate is welded to the battery can, the internal pressure at which the vent part ruptures may be a pressure equal to or less than the pressure at which the cap plate is separated from the battery can due to damage to the joint by the welding. The internal pressure at which the vent part ruptures may be 29 kgf / cm 2 Below, 28.5 kgf / cm 2 Below 28 kgf / cm 2 Below, 27.5 kgf / cm 2 or less, or 27 kgf / cm 2 It may be as follows. According to one aspect, the internal pressure at which the vent part ruptures is 21 kgf / cm 2 More than 29 kgf / cm 2 Below, 24 kgf / cm 2 More than 29 kgf / cm 2 Below 25 kgf / cm 2 Exceeding 29 kgf / cm2 Hereinafter, or another range formed from a combination of the endpoints listed above may be formed. If the internal pressure at which the vent part ruptures is outside the aforementioned range, the electrode assembly may not be discharged outside the battery can. In addition, if the electrode assembly is discharged, there is a possibility that the electrode assembly may not be discharged only through the first end of the battery can, which may cause damage to the side surface of the battery can. Therefore, if the internal pressure at which the vent part ruptures is within the aforementioned range, as described above, the safety of the battery and the battery can can be improved by allowing at least a portion of the electrode assembly to be discharged through the first end of the battery can without rupturing the side surface of the battery can. The internal pressure at which the vent part ruptures may vary at least in part depending on the shape, size, material, or thickness of the vent part, the difference in thickness between the vent part and the surrounding area, etc.

[0104] Referring to FIG. 5 according to one aspect, the ratio of the maximum width (w2) in the cross section in the vertical direction of the winding axis of the electrode assembly (10) to the maximum width (w1) in the cross section in the vertical direction of the winding axis of the battery can (20) may be less than 1. When the lithium secondary battery is cylindrical, the maximum width w1 or w2 in the cross section in the vertical direction of the winding axis of each of the battery can (20) or the electrode assembly (10) may be the diameter of the battery can (20) or the electrode assembly (10) passing through the winding axis (winding center C). FIG. 5 illustrates a cross section in the vertical direction of the winding axis of the electrode assembly (10), and the ratio of the maximum width (w2) of the electrode assembly (10) to the maximum width (w1) of the battery can (20) may be less than 1. For example, the ratio of w2 to w1 may be 0.995 or less, 0.99 or less, 0.985 or less, 0.98 or less, 0.975 or less, 0.97 or less, 0.968 or less, or 0.965 or less. In one aspect, after the electrolyte is injected into the battery can and before the electrode assembly is discharged, while the electrode assembly is immersed in the electrolyte, the ratio of the maximum width in the cross section in the vertical direction of the winding axis of the electrode assembly to the maximum width in the cross section in the vertical direction of the winding axis of the battery can may be less than 1. In one aspect, before the electrolyte is injected into the battery can, the ratio of the maximum width in the cross section in the vertical direction of the winding axis of the electrode assembly to the maximum width in the cross section in the vertical direction of the winding axis of the battery can may be less than 1. The smaller the maximum width in the vertical cross-section of the winding axis of the electrode assembly, the less physical resistance there is when the electrode assembly is pulled out of the battery can, so the force discharged to the first end of the battery can can be made larger.Therefore, by adjusting the ratio of the maximum width in the cross-section in the vertical direction of the winding axis of the electrode assembly to the maximum width in the cross-section in the vertical direction of the winding axis of the battery can as described above, the rupture of the side surface of the battery can can be prevented.

[0105] According to one aspect of the present invention, a sealing tape comprising polypropylene or polyimide may be attached to the outermost end of the electrode assembly. According to some aspects of the present invention, the sealing tape may comprise polypropylene. Referring to FIG. 6, a sealing tape (80) is attached to an outer side of the electrode assembly (10). The sealing tape (80) may serve to secure the outermost end of the electrode assembly (10) when the electrode assembly (10) is of the jelly-roll type. The sealing tape (80) is attached so as to cover at least a portion of the side of the electrode assembly, including the outermost end of the electrode assembly (10).

[0106] The surface of the sealing tape (80) facing the battery can may be made of a material that does not react with the electrolyte solvent and can maintain its original shape after exposure to the electrolyte solvent. For example, the surface of the sealing tape (80) facing the battery can may be made of polypropylene or polyimide. Since polypropylene or polyimide does not react with the electrolyte solvent, it can maintain its original shape as described above. Due to the presence of the sealing tape as described above, the physical resistance when the electrode assembly is pulled out of the battery can is low, so that at least a portion of the electrode assembly can be easily pulled out of the battery can, thereby preventing the side surface of the battery can from being ruptured. In addition, the use of the sealing tape (80) as described above can allow the electrode assembly (10) to be ejected with a strong force through the first end (E1) of the battery can. This may be at least in part due to the relatively smooth surface of the polypropylene or polyimide material. According to one or more aspects, the sealing tape (80) includes a substrate and an adhesive layer. The substrate is made of polypropylene or polyimide. The adhesive layer is attached to a side of the electrode assembly, including the outermost end of the electrode assembly (10). Here, the adhesive layer is not particularly limited, and any material known to those skilled in the art may be used. For example, the adhesive layer may be made of any material that does not chemically react with the battery, and non-limiting examples include acrylic adhesives, SBR adhesives, and the like.

[0107] The above sealing tape (80) may have a width (ts) that is 0.1 times or more, 0.2 times or more, 0.3 times or more, 0.4 times or more, 0.5 times or more, 0.6 times or more, 0.7 times or more, or 0.8 times or more the distance (t2) between the two ends of the electrode assembly (10) or the length of the battery can (the distance between the first end (E1) and the second end (E2)) in the winding axis direction (y) of the electrode assembly (10). In addition, the sealing tape (80) may have a width (ts) of 0.95 times or less, 0.9 times or less, 0.8 times or less, 0.7 times or less, 0.6 times or less, or 0.5 times or less, relative to the distance (t2) between the two ends of the electrode assembly (10) or the length of the battery can (the distance between the first end (E1) and the second end (E2)) in the winding axis direction (y) of the electrode assembly (10). The sealing tape (80) may have a length of 0.1 times or more, 0.2 times or more, 0.3 times or more, 0.4 times or more, 0.45 times or more, 0.5 times or more, 0.6 times or more, 0.7 times or more, 0.8 times or more, 0.9 times or more, or 0.95 times or more relative to the outermost circumference of the electrode assembly (10) in the circumferential direction (X) of the electrode assembly (10). The sealing tape (80) may have a length of 1 to 0.98 times the outermost circumference of the electrode assembly (10) in the circumferential direction (X) of the electrode assembly (10). Since the sealing tape having the above width and length has a surface facing the battery can made of polypropylene or polyimide, the electrode assembly (10) can be ejected with a strong force through the first end (E1) of the battery can. For example, when the lithium secondary battery has 4680 cells, the width (fs) of the sealing tape (80) may be 30 to 65 mm, and the length in the circumferential direction (X) of the electrode assembly (10) may be 130 to 135 mm.

[0108] According to one aspect, as shown in FIGS. 1A and 1B, it includes a first current collecting plate (30) provided between the first end (E1) of the battery can (20) and the electrode assembly (10).

[0109] According to one aspect, the first current collecting plate may have a battery can joint having a tapered structure. The tapered structure may be a portion welded to the battery can. By using a first current collecting plate including a battery can joint having a tapered structure as described above, when the electrode assembly (10) passes through the first end (E1) of the battery can (20), the first current collecting plate can be easily lost. This can minimize the effect of the first current collecting plate on the discharge of the electrode current collector (10). Therefore, when adopting the tapered structure as described above, the rupture of the side portion of the battery can can be prevented or minimized when the pressure inside the battery can increases. Fig. 7 illustrates an example of a battery can joint having a tapered structure of the first current collecting plate. The tapered structure may have a minimum width (w4) that is close to the center side of the battery can or the electrode assembly. The tapered structure may have a maximum width (w3) in a direction perpendicular to a diameter passing through the central axis of the battery can or the electrode assembly. The ratio of w4 to w3 may be 0.7 or less, 0.6 or less, 0.5 or less, 0.45 or less, 0.4 or less, or 0.3 or less. The minimum width (w4) present close to the center of the battery can or the electrode assembly of the tapered structure may be equal to the width of the connecting portion (33b) described below.

[0110] According to one aspect, as shown in FIG. 1A, the first current collecting plate (30) includes a support portion (31) positioned on one surface of the electrode assembly (10) and a plurality of battery can coupling portions (33) extending from the support portion (31) and coupled to an inner surface of the battery can (20). At least one of the support portion (31) and the battery can coupling portion (33) may be electrically connected to the electrode assembly (10). For example, a tab (non-conductive portion) of the electrode assembly may be coupled to at least one of the support portion (31) of the first current collecting plate (30) and the battery can coupling portion (33).

[0111] Referring to FIG. 4 according to an additional aspect, the electrode assembly (10) includes a non-conductive portion (11) that functions as a tab because an active material layer is not formed in a portion that comes into contact with the first current collecting plate (30), and referring to FIG. 1A, the first current collecting plate (30) may further include a tab coupling portion (32) coupled to the non-conductive portion. As shown in FIG. 8, the tab coupling portion (32) and the battery can coupling portion (33) may have a structure in which they are indirectly connected through the support portion (31) and are not directly connected to each other. That is, the tab coupling portion (32) and the battery can coupling portion (33) have a structure in which they extend separately from the support portion (31), and thus are not directly connected to each other, but are electrically connected through the support portion (31). In the case of having such a structure, when an external impact is applied to the battery (1), the possibility of damage occurring to the joint portion of the current collecting plate (30) and the electrode assembly (10) and the joint portion of the current collecting plate (30) and the battery can (20) can be minimized.

[0112] The tab coupling portion (32) and / or the battery can coupling portion (33) may be provided one at a time, or may be provided in multiples. At least one tab coupling portion (32) and at least one battery can coupling portion (33) may be arranged radially or approximately cross-shapedly with respect to the center of the first current collecting plate (30), or in a combination thereof. In another aspect, each of the plurality of battery can coupling portions (33) may be arranged between adjacent tab coupling portions (32).

[0113] Referring to Fig. 1a, the support portion (31) and a plurality of tab-connecting portions (32) are arranged on the upper portion of the electrode assembly (10). The tab-connecting portions (32) are connected to the non-conductive portion (11) of the electrode assembly (10). The tab-connecting portions (32) can be connected to the non-conductive portion (11) by welding along the radial direction of the electrode assembly (10). For example, the tab-connecting portions (32) can be connected to the non-conductive portion (11) by welding in a state parallel to the first or second end of the battery can (20).

[0114] Meanwhile, not only the tab joint (32), but also the support (31) may be joined to the non-beaded portion (11). The tab joint (32) and the non-beaded portion (11) may be joined by welding. The support (31) and the tab joint (32) are located lower (inside the battery can) than the beaded portion (21) when the beaded portion (21) is formed in the battery can (20).

[0115] Referring to FIG. 1A and FIG. 8 according to one aspect, the support member (31) may be provided with a current collecting plate hole (H2) formed at a position corresponding to a winding hole (H1) formed at approximately the center of the electrode assembly (10). The winding hole (H1) and the current collecting plate hole (H2) may be connected to each other, and may function as a passage for insertion of a welding rod or irradiation of a laser beam for welding between the terminal (50) and / or the second current collecting plate (P) or welding between the terminal (50) and a lead tab (not shown). Here, the second current collecting plate (P) may be provided between the second end (E2) of the battery can (20) and the electrode assembly (10).

[0116] 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 that the current collector plate (30) does not cover the winding hole (H1) formed in the core of the electrode assembly (10). In this case, since the winding hole (H1) of the electrode assembly is not covered by the current collector plate (30), a decrease in the injection property can be prevented, and also, sufficient space can be secured for insertion of a device for welding or laser irradiation. In addition, when the electrode assembly is discharged through the first end of the battery can due to an increase in the internal pressure of the battery can, the strong pressure of the gas released through the first end at the winding center (C) of the electrode assembly (10) causes the upper surface of the separator and the electrode plate (a portion adjacent to the first end of the battery can) at or near the winding center of the electrode assembly (10) to escape through the first end.

[0117] Referring to FIG. 1A and FIG. 8, the plurality of tab coupling portions (32) may have a shape extending approximately radially from the support portion (31) of the first current collecting plate (30) toward the side wall of the battery can (20). Each of the plurality of tab coupling portions (32) may be positioned spaced apart from each other along the periphery of the support portion (31). Meanwhile, in order to secure bonding strength and reduce electrical resistance by increasing the bonding area between the first current collecting plate (30) and the electrode assembly (10), not only the tab coupling portions (32) but also the support portion (31) may be bonded to the non-coated portion (11).

[0118] Referring to FIGS. 1A, 4, and 8, at least a portion of the non-coated portion (11) may be formed into a bent shape such that its end is approximately parallel to the tab-joining portion (32). In this case, the bending may be, for example, directed toward the winding center (C) of the electrode assembly (10). When the end of the non-coated portion (11) is formed in this way and is coupled to the tab-joining portion (32) in a state parallel to the tab-joining portion (32), the bonding area can be increased, thereby improving bonding strength and reducing electrical resistance. In addition, the layer height of the electrode assembly (10) can be minimized, thereby improving energy density. Meanwhile, the end (11a) of the bent non-coated portion (11) may be overlapped in multiple layers. In this case, when multiple layers of the non-conductive portion (11) are overlapped, the tab coupling portion (32) of the first collector plate (30) can be coupled on the coupling surface formed by the non-conductive portion (11) being banded and overlapped in multiple layers.

[0119] Referring to FIG. 1A and FIG. 8, the plurality of battery can coupling portions (33) may have a shape extending approximately radially from the support portion (31) of the first current collecting plate (30) toward the side wall of the battery can (20). Each of the plurality of battery can coupling portions (33) may be positioned spaced apart from each other along the periphery of the support portion (31). At least one battery can coupling portion (33) may be positioned between adjacent tab coupling portions (32). The plurality of battery can coupling portions (33) may be coupled to the inner surface of the battery can (20). For example, the battery can coupling portions (33) may be coupled to the beading portion (21). On one or more sides, the battery can coupling portions (33) may be coupled to the upper surface of the beading portion (21). In the battery (1) of the present invention, when such a structure is applied, the battery can joining portion (33) can be naturally seated on the beading portion (21) through a process of accommodating the electrode assembly (10) with the first current collecting plate (30) joined within the battery can (20). Therefore, the welding process of the battery can (20) and the first current collecting plate (30) can be easily performed. For example, laser welding, resistance welding, ultrasonic welding, soldering, or spot welding can be applied for the welding for joining the battery can (20) and the first current collecting plate (30). In this way, by welding the battery can joining portion (33) on the beading portion (21) to form multiple current paths, the resistance level can be limited to approximately 4 milliohm or less, which is suitable for rapid charging.

[0120] The above battery can coupling portion (33) includes a coupling portion (33a) coupled to a bead portion (21) on the inner surface of the battery can (20) and a connecting portion (33b) connecting between the support portion (31) and the coupling portion (33a).

[0121] The above-described joining portion (33a) is joined on the inner surface of the battery can (20). In the case where the beading portion (21) is formed on the battery can (20), the joining portion (33a) may be joined on the beading portion (21) as described above. The joining portion (33a) may have a shape corresponding to the shape of the upper surface of the beading portion (21). According to one aspect, for stable contact and joining, both the beading portion (21) and the joining portion (33a) may have a shape that extends in a direction approximately parallel to the lower surface of the battery can (20), that is, in a direction approximately perpendicular to the side wall of the battery can (20). The joining portion (33a) may have a flat surface that is joined with the upper surface of the beading portion (21) facing the opening side. That is, the joining portion (33a) includes a flat portion that is approximately parallel to the lower surface of the battery can (20). When the battery can joint (33) is in stable contact with the beading portion (21), welding between the two parts can be performed smoothly, thereby improving the bonding strength between the two parts and minimizing the increase in resistance at the joint area.

[0122] The above-mentioned connecting portion (33b) may extend in the radial direction and the winding axial direction. The connecting portion (33b) may have a convex structure toward the upper side (toward the first end (E1) of the battery can (20)) and may have at least one bent portion. For example, the boundary point between the joining portion (33a) and the connecting portion (33b) may be bent at an obtuse angle. The inclination of the connecting portion (33b) may gradually or gradually decrease as the connecting portion (33b) moves toward the beading portion.

[0123] As illustrated in Fig. 8, the connecting portion (33b) may have at least one bending portion whose extension direction changes at least once between the support portion (31) and the joining portion (33a). That is, the connecting portion (33b) may have, for example, a spring-like structure or a javara-like structure that can contract and expand within a certain range. Meanwhile, the connecting portion (33b) may be elastically biased upward by the bending portion. The structure of the connecting portion (33b) allows the joining portion (33a) to be in close contact with the beading portion (21) during the process of accommodating the electrode assembly (10) to which the first current collecting plate (30) is joined within the battery can (20), even if there is a height dispersion of the electrode assembly (10) within a certain range. In addition, according to the structure of the connecting portion (33b), the shape can be implemented more stably during the sizing process.

[0124] Referring to FIG. 1A and FIG. 8, the connecting portion (33a) can be welded to the upper surface of the beading portion (21) (the upper surface of the upper beading portion). Furthermore, the connecting portion (33a) can be welded to a flat area on the upper surface of the beading portion (21). The welding area between the connecting portion (33a) and the beading portion (21) can be formed to be narrower than the flat upper surface of the beading portion (21). When a bending portion is provided in the connecting portion (33b), the angle between the connecting portion (33a) and the connecting portion (33b) can become an acute angle due to the bending portion.

[0125] According to one aspect, when the first current collecting plate is projected onto the opening area of ​​the first end of the battery can, the area of ​​the portion where the first current collecting plate is projected may be 50% to 70% based on the entire opening area of ​​the first end. The opening area of ​​the first end of the battery can may not include the side thickness of the battery can. In addition, when the clamping portion (22) or the beading portion (21) is present on the side of the first end of the battery can and the width of the battery can is narrowed, the opening area of ​​the first end means an opening area having a minimum width. Projecting the first current collecting plate means projecting the first current collecting plate onto the opening area in a direction parallel to the side surface of the battery can. The above-mentioned area range corresponds to a flame-exhaustible area where the electrode assembly directly faces the opening of the first end of the battery can without interposing the first current collecting plate.

[0126] According to one aspect, the flame exhaust possible area may be approximately 30% to 50% of the total opening area of ​​the first end of the battery can. By controlling the flame exhaust possible area in this way, when the pressure inside the battery can increases, pressure or flame can be effectively removed, thereby preventing or minimizing rupture of the side of the battery can. The flame exhaust possible area may be an area excluding an area on which the first collector plate is projected from the opening area of ​​the first end of the battery can, such as part A indicated by hatching in FIG. 11. The outer diameter of part A indicated by hatching in FIG. 11 is the outermost part of the opening area of ​​the first end of the battery can excluding an area on which the clamping portion (22) or the beading portion (21) of the battery can is projected. The flame exhaust possible area is the entire area surrounded by the outer diameter of part A indicated by hatching in FIG. 11, that is, the area excluding an area on which the first collector plate is projected from the entire opening area. The above flame exhaust area range serves to reduce the resistance of the battery during normal use of the battery, but can allow the first current collector plate to be easily destroyed when the electrode assembly is discharged through the first end of the battery can. The above flame exhaust area range can be adjusted by adding holes and / or slits to the support portion (31), adjusting the area of ​​the support portion (31) and / or the tab joint portion (32), adjusting the width of the connection portion (33b), etc.

[0127] The above flame exhaust area may be 30% or more and 50% or less based on the total opening area of ​​the first end of the battery can, and the lower limit may be 30% or more, 35% or more, 36% or more, 37% or more, 38% or more, 39% or more, 40% or more, 41% or more, 42% or more, 43% or more, 44% or more, 45% or more, 46% or more, or 47% or more.

[0128] Referring to FIG. 9 according to one aspect, the support member (31) may include one or more holes (H3). The holes (H3) may be one or two or more around the current collector plate hole (H2). As illustrated in FIG. 10, a slit (S1) extending the hole (H3) and the current collector plate hole (H2) may be additionally provided. The size or area of ​​the hole (H3) and the slit (S1) may be designed in consideration of the area of ​​the first current collector plate or the reduction in electrical resistance described above. In addition, by adjusting the width of the connecting portion (33b) of the first current collector plate (30), the first current collector plate (30) may be easily lost as the connecting portion (33b) is broken when the electrode assembly is discharged through the first end of the battery can. For example, when the electrode assembly is discharged through the first end of the battery can, 50% or more, 70% or more, or 75% or more of the plurality of connecting portions (33b) may be completely cut.

[0129] The size of the hole (H3), the area (or width) of the slit (S1), and / or the width of the connection portion (33b) of the first current collecting plate (30) can be designed so that, when the first current collecting plate is projected onto the opening area of ​​the first end of the battery can described above, the area of ​​the portion where the first current collecting plate is projected is 50% to 70% of the total opening area of ​​the first end. In other words, the size of the hole (H3), the area (or width) of the slit, and / or the width of the connecting portion (33b) of the first current collecting plate (30) can be designed so that the flame exhaust possible area is approximately 30% to 50%, 35% to 50%, 36% to 50%, 34% to 36%, 38% to 40%, or 44% to 47% of the total opening area of ​​the first end of the battery can.

[0130] In one aspect, the thickness of the first current collecting plate may be 0.4 mm or less, 0.35 mm or less, 0.3 mm or less, 0.25 mm or less, or 0.2 mm or less. When the thickness of the first current collecting plate is thin, the side rupture of the battery can caused by the electrode assembly can be effectively prevented even when the pressure inside the battery can increases. Specifically, since the first current collecting plate is easily lost even when the pressure inside the battery can increases, the electrode assembly can be easily discharged through the first end.

[0131] Fig. 12 is a cross-sectional view of an electrode plate (positive electrode plate or negative electrode plate) according to one aspect of the present invention. Referring to Figs. 3 and 11, the positive electrode plate (210) and the negative electrode plate (211) have a structure in which an active material layer (221) is formed on a sheet-shaped current collector (220). The sheet-shaped current collector (220) may include a non-conductive portion (222) on which the active material layer (221) is not formed.

[0132] As described above, by using the positive electrode plate (210) and the negative electrode plate (211) including the non-coated portion (222), a battery having a tab-less structure without separate electrode tabs can be formed. In the battery having such a tab-less structure, at least a part of the non-coated portions of the positive electrode plate (210) and the negative electrode plate (211) functions as an electrode tab. Specifically, the non-coated portion (222) can be formed to extend along the winding direction (X) at one end of the current collector (220). A current collecting plate can be coupled to each of the positive electrode non-coated portion and the negative electrode non-coated portion, and by connecting the current collecting plate to each of the positive terminal and the negative electrode terminal, a battery having a tab-less structure can be implemented. Reference numerals 11 and 12 of FIGS. 1A and 1B represent the non-coated portion of the negative electrode plate (211) and the non-coated portion of the positive electrode plate (210) of FIG. 3, respectively.

[0133] The non-coated portions of the positive and negative electrode plates may be processed into a plurality of independently foldable segments (11a), and at least some of the segments may be folded toward the winding center (C) of the electrode assembly, as illustrated in Fig. 4. The segments may be formed by processing the non-coated portions of the positive and negative electrode plates through a metal foil cutting process such as laser notching, ultrasonic cutting, or punching.

[0134] When the non-coated portions of the positive and negative electrode plates are processed into multiple segments, the stress applied to the non-coated portions during bending can be reduced. This can prevent deformation or breakage of the non-coated portions and improve welding characteristics with the current collector plate.

[0135] The above-described collector plate and the non-coated portion can be joined by welding. To improve welding properties, strong pressure can be applied to the welding area of ​​the non-coated portion to fold the non-coated portion as flat as possible. However, during this bending process, the shape of the non-coated portion may become irregularly distorted and deformed. This deformed area may contact an electrode of opposite polarity, causing an internal short circuit or causing micro-cracks in the non-coated portion. However, if the non-coated portions of the positive and negative plates are processed into multiple independently bendable segments, the stress applied to the non-coated portion during bending can be alleviated. This can minimize deformation and breakage of the non-coated portion.

[0136] In addition, when the non-conductive portion is processed in the form of segments as described above, an overlap occurs between the plurality of segments when folded. This increases the welding strength with the current collector plate, and when using the latest technology such as laser welding, it can prevent the problem of the laser penetrating into the electrode assembly and melting the separator or active material. According to one or more aspects of the present invention, at least some of the folded plurality of segments may overlap on the upper and lower sides of the electrode assembly, and the current collector plate may be bonded on the plurality of overlapped segments.

[0137] For example, a battery having a tab-less structure can be manufactured by the following method. First, a separator, a positive electrode plate, a separator, and a negative electrode plate are sequentially laminated so that the non-coated portions (222) of the positive electrode plate (210) and the negative electrode plate (211) are positioned in opposite directions. The laminate is wound in one direction to manufacture an electrode assembly. Then, as shown in FIG. 4, the non-coated portion (12) of the positive electrode plate and the non-coated portion (11) of the negative electrode plate are bent toward the winding center (C). A current collector plate is welded to each of the non-coated portions (12) of the positive electrode plate and the non-coated portion (11) of the negative electrode plate, respectively, and the current collector plate is connected to an electrode terminal, thereby manufacturing a battery having a tab-less structure.

[0138] The above current collecting plate may include a first current collecting plate (30) and a second current collecting plate (P) as illustrated in FIG. 1a or FIG. 1b. The current collecting plate has a larger cross-sectional area than the electrode tab, and since the resistance is inversely proportional to the cross-sectional area of ​​the path through which the current flows, when a lithium secondary battery is formed with the above structure, the battery resistance can be significantly reduced. The first current collecting plate (30) and the second current collecting plate (P) may be respectively coupled to the negative plate non-conducting portion (11) and the positive plate non-conducting portion (12), or respectively coupled to the positive plate non-conducting portion (12) and the negative plate non-conducting portion (11), and each of them is connected to an electrode terminal (i.e., a positive terminal or a negative terminal).

[0139] The above current collecting plate may be made of a conductive metal material such as aluminum, copper, nickel, etc. Additional leads may be connected to the first and / or second current collecting plates, as needed. The leads may electrically connect the current collecting plate to the cap plate and / or electrode terminal. The leads may be joined to other components by welding. For example, the current collecting plate may be formed integrally with the leads. In this case, the leads may have an elongated plate shape extending outward from the center of the current collecting plate.

[0140] The first current collecting plate (30) is coupled between the electrode assembly (10) and the first end (E1) of the battery can, and the second current collecting plate (P) is coupled between the electrode assembly (10) and the second end (E2) of the battery can. One side of the current collecting plate (P) is coupled to the non-coated portion (11) of the negative electrode plate or the non-coated portion (12) of the positive electrode plate, and the opposite side can be electrically coupled to the inner bottom surface of the battery can (20) or the cap plate. At this time, the coupling can be performed by a method such as laser welding, resistance welding, ultrasonic welding, or soldering.

[0141] The battery (1) according to the present invention may further include an insulator (S). The insulator (S) of FIGS. 1A and 1B can prevent direct contact between the second current collecting plate (P) and the inner surface of the battery can (20) by covering at least a portion of the second current collecting plate (P). The insulator (S) may be made of a polymer resin material having insulating properties, such as polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

[0142] According to one or more aspects of the present invention, the battery can (20) is a cylindrical container having an opening formed at the upper end (first end or second end) and may be made of a conductive metal material such as aluminum or steel. According to one aspect, the battery can (20) is electrically connected to the non-conductive portion (11) of the negative electrode plate and functions as a negative terminal that contacts an external power source and transmits current applied from the external power source to the negative electrode plate.

[0143] According to one aspect, the thickness of the side of the battery can (20) may be 0.1 mm to 0.4 mm. For example, the thickness of the side of the battery can (20) may be 0.13 mm to 0.32 mm. By improving the safety of the battery according to the aforementioned aspects, safety can be guaranteed even when the thickness of the battery can is as described above.

[0144] The lithium secondary battery according to the present invention may be a large-capacity secondary battery having a capacity of 25 Ah or more.

[0145] The lithium secondary battery according to the present invention may be a large-sized battery having a form factor ratio (defined as the ratio of the diameter (T) to the height (H) of a cylindrical battery, i.e., the diameter divided by the height) of 0.4 or more. Here, the form factor refers to a value indicating the diameter (maximum width) and height of the battery.

[0146] The battery according to the present invention may be, for example, a 46110 cell (diameter 46 mm, height 110 mm, form factor ratio 0.418), a 4875 cell (diameter 48 mm, height 75 mm, form factor ratio 0.640), a 48110 cell (diameter 48 mm, height 110 mm, form factor ratio 0.436), a 4880 cell (diameter 48 mm, height 80 mm, form factor ratio 0.600), a 4680 cell (diameter 46 mm, height 80 mm, form factor ratio 0.575), or a 4695 cell (diameter 46 mm, height 95 mm, form factor ratio 0.484). In the numerical value representing the form factor, the first two numbers represent the diameter of the battery, and the next two or three numbers represent the height of the battery.

[0147] According to the aspects of the present invention described above, excellent safety can be achieved even in large batteries having a form factor ratio of 0.4 or more.

[0148] Meanwhile, the lithium secondary battery according to the present invention is a battery having a tab-less structure that does not include electrode tabs.

[0149] A battery having the tab-less structure may have, for example, a structure in which each of the positive and negative electrode plates includes a non-conductive region on which an active material layer is not formed. The non-conductive region of the positive and negative electrode plates is positioned at the top and bottom of the electrode assembly, respectively. Current collector plates are respectively bonded to the non-conductive region of the positive and negative electrode plates, and the current collector plates are connected to electrode terminals. FIGS. 1A and 1B illustrate cross-sectional views of a cylindrical battery having a tab-less structure according to aspects of the present invention. However, the structure of the cylindrical battery of the present invention is not limited to the range disclosed in FIGS. 1A and 1B.

[0150] The positive electrode, negative electrode, separator, and electrolyte can be used without limitation as long as they are known in the art.

[0151] In one example, the positive electrode active material has the general chemical formula A[Ax M y ]O 2+z (wherein, A comprises at least one element selected from Li, Na, and K; M comprises at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, or Cr; x ≥ 0, 1 ≤ x+y ≤ 2, -0.1 ≤ z ≤ 2; and the stoichiometric coefficients x, y, and z are selected such that the compound maintains electrical neutrality).

[0152] In another example, the positive electrode active material is an alkali metal compound xLiM 1 O2-(1-x)Li2M 2 O3 (where M 1 contains at least one element having an average oxidation state of 3; M 2 contains at least one element having an average oxidation state of 4; and 0 ≤ x ≤ 1). Examples of the above positive electrode active material are disclosed in US6,677,082, US6,680,143, etc.

[0153] In another example, the positive electrode active material has the general chemical formula Li a M 1 x Fe 1-x M 2 y P 1-y M 3 z O 4-z (Here, M 1 Contains at least one of Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg or Al; M 2 Contains at least one of Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V or S; M 3may include a halogen element optionally including F; 0 < a ≤ 2, 0 ≤ x ≤ 1, 0 ≤ y < 1, 0 ≤ z < 1; and the stoichiometric coefficients a, x, y and z are selected so that the compound remains electrically neutral), or a lithium metal phosphate represented by Li3M2(PO4)3 [M includes at least one of Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg or Al].

[0154] According to one or more aspects of the present invention, the positive electrode active material may include primary particles and / or secondary particles formed by agglomerating primary particles.

[0155] For example, the negative active material can be carbon material, lithium metal or lithium metal compound, silicon or silicon compound, tin or tin compound, etc. The silicon compound can be pure silicon, silicon oxide, silicon-carbon complex, silicon metal alloy, etc. Metal oxides such as TiO2 and SnO2 with a potential of less than 2 V can also be used as the negative active material. The carbon material can be low-crystalline carbon or high-crystalline carbon.

[0156] The separator may include a porous polymer film. For example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer may be used alone or in a laminated manner. 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, or the like.

[0157] At least one surface of the membrane may include a coating layer of inorganic particles. Furthermore, the membrane itself may be formed of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound to a binder such that an interstitial volume exists between adjacent particles.

[0158] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or higher. As a non-limiting example, the inorganic particles may be Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), BaTiO3, hafnia(HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO and Y2O3.

[0159] Electrolyte is A + B - It may be a salt having a structure. Here, A + is Li + , Na + , K + It includes ions composed of alkali metal cations such as and combinations thereof. And B - is F -- , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4- , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - ,　 CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - Contains at least one anion selected from the group consisting of:

[0160] The electrolyte can also be dissolved in an organic solvent. Examples of the organic solvent include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), gamma butyrolactone, or mixtures thereof.

[0161] Referring to Fig. 13, a battery pack (3) includes a battery assembly in which a plurality of batteries (1) are electrically connected according to aspects of the present invention, and a pack housing (2) that accommodates the battery assembly. For convenience of illustration in the drawing, components such as a bus bar, a cooling unit, and a power terminal for electrical connection are omitted from Fig. 13. Similarly, the electrical connection structure of the plurality of batteries (1) for manufacturing the battery pack (3) is omitted.

[0162] Referring to Fig. 14, a vehicle (5) according to one aspect of the present invention may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle (5) may include a battery pack (3) according to one aspect of the present invention. The vehicle (5) may include a four-wheeled vehicle and a two-wheeled vehicle. The vehicle (5) operates by receiving power from the battery pack (3) according to one aspect of the present invention. The vehicle may reduce or eliminate greenhouse gas emissions, thereby mitigating the impact of climate change.

[0163]

[0164] One aspect of the present invention provides a battery comprising a can, a jelly roll, and a cap plate. The can comprises a cylindrical body, a first wall at a first end of the cylindrical body, and a second wall at a second end of the cylindrical body. The cylindrical body has a diameter and a length between the first end and the second end along a central axis of the cylindrical body. The jelly roll comprises a negative electrode, a separator, and a positive electrode, which are accommodated within the cylindrical body and wound together about the central axis. The battery comprises a rupture notch formed in the first wall or the second wall. The first wall comprises a cap plate hermetically integrated with the cylindrical body, wherein an edge portion (hereinafter referred to as a "crimping portion") of the cylindrical body near the first end is crimped around the cap plate, and the crimping portion is configured to unclamp when an internal pressure reaches an unclamping pressure. The burst pressure is configured to burst and create an opening when the internal pressure of the battery reaches the burst pressure. The burst pressure is lower than the unclamping pressure, so that the crimping portion does not unclamp when the internal pressure reaches the burst pressure. The predetermined burst pressure is set to be sufficient to generate an explosive force that ejects a portion of the jellyroll outside the cylindrical body, such that the ejected portion extends in a telescoping manner outside the cylindrical body along a central axis, wherein the inner portion of the jellyroll ejects before the outer portion of the jellyroll surrounding the inner portion inside the cylindrical body before rupture, and wherein a leading edge of the ejected portion reaches a distance of at least 1 / 4 length from the first end of the cylindrical body along the central axis, and wherein the portion ejected outside the cylindrical body is at least 25% by weight of the jellyroll located inside the can before rupture, and wherein the ejected portion located outside the cylindrical body does not cause any further chemical reaction that could lead to thermal runaway inside the cylindrical body.

[0165] In some respects, the predetermined burst pressure is approximately 21 kgf / cm 2 In some aspects, the predetermined burst discharge pressure is about 25 kgf / cm 2 About 29 kgf / cm 2 In some aspects, the battery is a 46110 cell battery, a 4875 cell battery, a 48110 cell battery, a 4880 cell battery, a 4680 cell battery, or a 4695 cell battery. In some aspects, the battery does not include another rupture notch or vent configured to vent gas. In some aspects, the cylindrical body has a side portion that ruptures at a side rupture pressure higher than a predetermined rupture pressure of the rupture notch. In some aspects, the ejected portion of the jellyroll electrode assembly has a spiral configuration. In some aspects, the form factor ratio of the battery is greater than or equal to 0.4. In some aspects, the cylindrical body has a side portion having a thickness of about 0.1 mm to about 0.4 mm. In some aspects, the second wall is formed integrally with the cylindrical body. In some aspects, the second wall is hermetically integral with the cylindrical body with or without a seam connecting the second wall therebetween. In some aspects, the rupture notch is formed in the cam plate of the first wall. In some aspects, the rupture notch is formed in the second wall.

[0166] One aspect of the present invention provides a battery pack comprising the battery described herein. One aspect of the present invention provides a vehicle comprising the battery pack described herein.

[0167]

[0168]

[0169] Thermal Runaway

[0170] Thermal runaway in batteries is a critical safety issue, especially for lithium-ion batteries used in consumer electronics, electric vehicles, and renewable energy storage. Thermal runaway is a self-sustaining reaction that, when the temperature rises, further increases, leading to a rapid and uncontrollable increase in heat. In batteries, this can lead to fire or explosion. Managing thermal runaway is essential for the safe operation of battery systems, especially as demand for large-capacity batteries continues to grow.

[0171]

[0172] Causes of thermal runaway

[0173] Thermal runaway can occur for a variety of reasons. For example, charging a battery beyond a certain level can generate excessive heat, which can decompose the electrolyte and release flammable gases. Manufacturing defects, mechanical damage, or degradation over time can cause internal short circuits, generating significant heat and potentially triggering thermal runaway. High external temperatures can overwhelm a battery's cooling mechanisms, causing temperatures to rise uncontrollably. Physical damage, such as punctures or deformations, can damage the battery's internal structure, leading to short circuits and heat generation. Operating a battery at a high discharge rate generates more heat, and if this heat exceeds the battery's dissipation capacity, thermal runaway can occur.

[0174]

[0175] Thermal runaway process

[0176] In the initial stage, external factors such as overcharging, overheating, or mechanical damage cause a localized rise in temperature within the battery cell. This initial heat can trigger chemical reactions, such as electrolyte decomposition. The heat generated in the initial stage can then trigger additional chemical reactions, generating more heat, leading to a feedback loop where temperatures continue to rise. In battery packs, thermal runaway can spread from one cell to adjacent cells, potentially leading to a large-scale event. This is particularly dangerous in applications such as electric vehicles.

[0177]

[0178] Existing methods for preventing and mitigating thermal runaway

[0179] Existing approaches to preventing and mitigating thermal runaway include the use of cooling systems, battery management systems, safety mechanisms, and heat-resistant materials and barriers. Effective cooling systems can dissipate heat and prevent temperature rise. Battery management systems can monitor and control the charging and discharging of batteries to prevent conditions that could lead to thermal runaway. Building batteries from materials that can withstand higher temperatures and inserting physical barriers between cells can reduce the risk of heat transmission. Incorporating safety features such as thermal fuses, pressure relief valves, and / or gas vents can help mitigate the effects of thermal runaway. For example, pressure relief valves and gas vents release generated gases and heat before the internal pressure of the battery becomes too high. These valves and vents typically open when the internal pressure of the battery is relatively low, allowing the gases and heat to escape. Similarly, rupture notches can be implemented to rupture the battery can before the internal pressure becomes too high to avoid or minimize the possibility of explosion.

[0180]

[0181] A new approach

[0182] Unlike conventional thinking that uses gas vents and / or pressure relief valves that open at relatively low pressures to relieve pressure or release generated gases and heat, the present disclosure surprisingly provides a rupture notch sufficient to prevent and / or mitigate and / or stop thermal runaway within the cell by allowing the internal pressure of the cell to build up and increase to a certain level, thereby generating an explosive force capable of ejecting a portion of the jellyroll electrode assembly outside the cell body.

[0183]

[0184] burst notch

[0185] In some aspects, the rupture notch (41, 201) may be at the first end (E1) of the battery can (20), as illustrated in FIGS. 1A and 1B. In the aspect illustrated in FIG. 1A, the rupture notch (41) may be a part of a cap plate (40) that is hermetically integrated into the cylindrical body (20). In the aspect illustrated in FIG. 1B, the rupture notch (201) may be a part of a bottom plate of the battery. The rupture notch may include one or more weak points in the cap plate (40) or the bottom plate. In some aspects, the rupture notch may be a weak point of, for example, a circle, a square, or any other arbitrary shape, centered about a center C illustrated in FIG. 14, and may be located at a middle portion of the cap plate (40) or the bottom plate of the battery. In some other aspects, the rupture notch may include a plurality of weak points, for example, forming a circular, rectangular or other shape, which are located in the middle of the cap plate (40) or the bottom plate of the battery about a center C. When the internal pressure of the battery reaches a predetermined rupture pressure, the rupture notch ruptures, creating an opening (not shown) in the cap plate (40) or the bottom plate. The internal pressure or predetermined rupture pressure that ruptures the rupture notch may vary depending on the shape, geometry, size, material, thickness and / or surface treatment of the rupture notch, the thickness difference between the rupture notch and the surrounding area, etc., which are well known in the art and will not be described in detail herein.

[0186]

[0187] Crimping section

[0188] As illustrated in FIGS. 1A and 1B, a circumferential portion of the cap plate (40) is surrounded by a crimping portion (22) at a first end (E1) or a second end (E2). The crimping portion (22) secures the cap plate (40) to the end E1 or E2 of the battery can (20). The crimping portion (22) may be formed in the beading portion (21), and extends and bends to surround an outer peripheral surface of the cap plate (40) disposed in the beading portion (21) and to surround a portion of an upper surface of the cap plate (40). An insulating sealing gasket (G1) is provided between the cap plate (40) and the crimping portion (22) to provide sealing therebetween, so that the cap plate (40) is hermetically integrated into the cylindrical body (20) of the battery.

[0189]

[0190] Form factor and predetermined burst pressure

[0191] The predetermined burst pressure is designed to be sufficient to generate a burst force that ejects at least a portion of the jellyroll electrode assembly through the opening in the battery can a distance from the first end (E1), i.e., a distance of at least ¼ of the length of the cylindrical body of the battery can, such that the ejected portion of the jellyroll electrode assembly has a mass that is at least 25% of the total mass of the jellyroll electrode assembly before ejection. The predetermined burst pressure may be determined based on the diameter (maximum width) and / or length of the battery and / or the size of the opening. For example, a larger opening requires a higher predetermined burst pressure to generate the same burst force. For a battery of the same diameter, a longer battery has a greater mass of the jellyroll electrode assembly; and for a battery with the same size opening when the burst notch ruptures, a greater burst force is required to eject the jellyroll electrode assembly a same distance, and thus a higher predetermined burst pressure. The predetermined burst pressure may be determined based on the form factor of the battery. Here, form factor refers to the values ​​representing the diameter and length (or height) of the battery.

[0192]

[0193] Predetermined bursting pressure and unclamping pressure

[0194] In some aspects, the rupture notch may be in the center of the cap plate or bottom plate of the battery, and thus the opening created by the rupture of the rupture notch is also in the center of the cap plate or bottom plate. The unclamping portion is designed to have an unclamping pressure higher than a predetermined bursting pressure, so that the crimping portion (22) is not unclamped when the internal pressure reaches the predetermined bursting pressure and ruptures the rupture notch (41, 201). Therefore, the inner portion of the jellyroll electrode assembly is ejected through the opening before the outer portion of the jellyroll electrode assembly surrounding the inner portion is ejected. The crimping portion 22 may be made of a material or may have a thickness, size, and / or shape that provides a relatively higher unclamping pressure compared to the predetermined bursting pressure. For example, when the crimping portion is made of a hard material, its unclamping pressure may be higher than the unclamping pressure of a crimping portion made of a softer material having a similar shape, thickness, and / or size. When other factors such as material hardness, shape, and thickness are similar, a larger crimping section may have a higher unclamping pressure than a smaller crimping section. A crimping section with a more curved shape may have a higher unclamping pressure than a crimping section with a less curved shape.

[0195]

[0196] Example of a predetermined burst pressure

[0197] In some aspects, the predetermined burst pressure is about 0.1 kgf / cm 2Above, for example, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 17, 19, 20, 21, 21.1, 21.2, 21.3, 21.4, 21.5, 21.6, 21.7, 21.8, 21.9, 22, 22.1, 22.2, 22.3, 22.4, 22.5, 22.6, 22.7, 22.8, 22.9, 23, 23.1, 23.2, 23.3, 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, 25, 25.1, 25.2, 25.3, 25.4, 25.5, 25.6, 25.7, 25.8, 25.9, 26, 26.1, 26.2, 26.3, 26.4, 26.4, 26.6, 26.7, 26.8, 26.9, 27,27.1, 27.2, 27.3, 27.4, 27.5, 27.6, 27.7, 27.8, 27.9, 28, 28.1, 28.2, 28.3, 28.4, 28.5, 28.6, 28.7, 28.8, 28.9, 29, 29.1, 29.2, 29.3, 29.4, 29.5, 29.6, 29.7, 29.8, 29.9, 30, 30.1, 30.2, 30.3, 30.4, 30.5, 30.6, 30.7, 30.8, 30.9, 31, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 53, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100 kgf / cm 2In some aspects, the predetermined burst pressure may be within a range formed by selecting any two numbers listed herein, for example, from about 0.2 to about 62 kgf / cm 2 , about 0.1 to about 10 kgf / cm 2 , about 0.3 to about 25 kgf / cm 2 , about 1 to about 21 kgf / cm 2 , about 2 to about 42 kgf / cm 2 , about 5 to about 55 kgf / cm 2 , about 6 to about 6 kgf / cm 2 , about 7 to about 35 kgf / cm 2 , about 21 to about 29 kgf / cm 2 , about 21.5 to about 30.5 kgf / cm 2 , about 23.5 to about 27.5 kgf / cm 2 , about 23 to about 33 kgf / cm 2 , about 24 to about 29 kgf / cm 2 , about 24.2 to about 28.9 kgf / cm 2 , about 25.1 to about 29 kgf / cm 2 , about 25 to about 29 kgf / cm 2 , about 26 to about 29 kgf / cm 2 , about 27 to about 29 kgf / cm 2 , about 25 to about 28 kgf / cm 2 , about 24.3 to about 27.8 kgf / cm 2 , about 28 to about 38 kgf / cm 2 It could be the back.

[0198]

[0199] Example of unclamping pressure

[0200] In some aspects, the unclamping pressure is about 10 kgf / cm 2It can be more than about 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21.1, 21.2, 21.3, 21.4, 21.5, 21.6, 21.7, 21.8, 21.9, 22, 22.1, 22.2, 22.3, 22.4, 22.5, 22.6, 22.7, 22.8, 22.9, 23, 23.1, 23.2, 23.3., 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, 25, 25.1, 25.2, 25.3, 25.4, 25.5, 25.6, 25.7, 25.8, 25.9, 26, 26.1, 26.2, 26.3, 26.4, 26.4, 26.6, 26.7, 26.8, 26.9, 27,27.1, 27.2, 27.3, 27.4, 27.5, 27.6, 27.7, 27.8, 27.9, 28, 28.1, 28.2, 28.3, 28.4, 28.5, 28.6, 28.7, 28.8, 28.9, 29, 29.1, 29.2, 29.3, 29.4, 29.5, 29.6, 29.7, 29.8, 29.9, 30, 30.1, 30.2, 30.3, 30.4, 30.5, 30.6, 30.7, 30.8, 30.9, 31, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 53, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, or 200 kgf / cm. 2 In some aspects, the unclamping pressure may be within a range formed by selecting any two numbers listed herein, for example, from about 10 to about 20 kgf / cm 2 , about 20 to about 50 kgf / cm 2 , about 50 to about 100 kgf / cm 2 , about 30 to about 60 kgf / cm 2 , about 40 to about 80 kgf / cm2 , about 10 to about 15 kgf / cm 2 , about 30 to about 40 kgf / cm 2 , about 40 to about 50 kgf / cm 2 , about 15 to about 20 kgf / cm 2 , about 21.1 to about 29.5 kgf / cm 2 , about 24 to about 33.1 kgf / cm 2 , about 27.4 to about 38 kgf / cm 2 , about 29.1 to about 40 kgf / cm 2 In some aspects, the unclamping pressure may be greater than the numbers listed herein, for example, about 29, 29.1, 29.5, 30, 33, 37, 40, 50, 60, 70, 80, 90, or 100 kgf / cm 2 In some aspects, the unclamping pressure may be more than any number higher than about 200 kgf / cm 2 It can be greater than any larger number, for example 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 350, 400, 500, or 600 kgf / cm 2 It could be the back.

[0201]

[0202] Examples of predetermined burst pressure and unclamping pressure

[0203] The above burst notch is designed so that the predetermined burst pressure is lower than the unclamping pressure, so that the crimping portion (22) is not unclamped when the internal pressure reaches the predetermined burst pressure to burst the burst notch (41, 201). For example, the predetermined burst pressure is about 21 to about 29 kgf / cm. 2, for example 21.1, 21.2, 21.3, 21.4, 21.5, 21.6, 21.7, 21.8, 21.9, 22, 22.1, 22.2, 22.3, 22.4, 22.5, 22.6, 22.7, 22.8, 22.9, 23, 23.1, 23.2, 23.3., 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, 25, 25.1, 25.2, 25.3, 25.4, 25.5, 25.6, 25.7, 25.8, 25.9, 26, 26.1, 26.2, 26.3, 26.4, 26.4, 26.6, 26.7, 26.8, 26.9, 27, 27.1, 27.2, 27.3, 27.4, 27.5, 27.6, 27.7, 27.8, 27.9, 28, 28.1, 28.2, 28.3, 28.4, 28.5, 28.6, 28.7, 28.8, 28.9, or 29 kgf / cm 2 may be; the unclamping pressure is about 29 kgf / cm 2 , may be greater than, for example, about 29.1, 29.2, 29.3, 29.4, 29.5, 29.6, 29.7, 29.8, 29.9, 30, 30.1, 30.2, 30.3, 30.4, 30.5, 30.6, 30.7, 30.8, 30.9, 31, 31.1, 31.2, 31.3, 31.4, 31.5, 31.6, 31.7, 31.8, 31.9, 32, 32.1, 32.2., 32.3, 32.4, 32.5, 32.6, 32.7, 32.8, 32.9, 33, 33.1, 33.2, 33.3, 33.4, 33.5, 33.6, 33.7, 33.8, 33.9, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50kgf / cm 2 , or 50 kgf / cm 2. may be any number greater than. In some aspects, the predetermined burst pressure may be within a range formed by selecting any two numbers provided herein, for example, from about 21.1 to about 29, from about 25 to about 29, from about 25.1 to about 29, from about 21 to about 24, from about 25 to about 28.9, from about 24.9 to about 29, from about 25.5 to about 29, from about 26 to about 29, from about 27 to about 29, from about 28 to about 29, from about 25 to about 28.5, from about 24.9 to about 28.9 kgf / cm 2 and the unclamping pressure may be within a range formed by selecting any two numbers provided herein, for example, about 29.1 to about 30.4, about 30.1 to about 34, about 35 to about 40, about 40 to about 45 kgf / cm 2 It could be the back.

[0204]

[0205] Additional examples of predetermined burst pressure and unclamping pressure

[0206] As an additional example, the unclamping pressure is about 40 kgf / cm 2 , may be greater than, for example, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 kgf / cm 2, or 60 kgf / cm 2 ; may be any number greater than; and the predetermined burst pressure is from about 21 to about 39 kgf / cm 2, for example 21.1, 21.2, 21.3, 21.4, 21.5, 21.6, 21.7, 21.8, 21.9, 22, 22.1, 22.2, 22.3, 22.4, 22.5, 22.6, 22.7, 22.8, 22.9, 23, 23.1, 23.2, 23.3., 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, 25, 25.1, 25.2, 25.3, 25.4, 25.5, 25.6, 25.7, 25.8, 25.9, 26, 26.1, 26.2, 26.3, 26.4, 26.4, 26.6, 26.7, 26.8, 26.9, 27,27.1, 27.2, 27.3, 27.4, 27.5, 27.6, 27.7, 27.8, 27.9, 28, 28.1, 28.2, 28.3, 28.4, 28.5, 28.6, 28.7, 28.8, 28.9, 29, 29.1, 29.2, 29.3, 29.4, 29.5, 29.6, 29.7, 29.8, 29.9, 30, 30.1, 30.2, 30.3, 30.4, 30.5, 30.6, 30.7, 30.8, 30.9, 31, 31.1, 31.2, 31.3, 31.4, 31.5, 31.6, 31.7, 31.8, 31.9, 32, 32.1, 32.2, 32.3, 32.4, 32.5, 32.6, 32.7, 32.8, 32.9, 33, 33.1, 33.2, 33.3, 33.4, 33.5, 33.6, 33.7, 33.8, 33.9, 34, 34.1, 34.2, 34.3, 34.4, 34.5, 34.6, 34.7, 34.8, 34.9, 35, 35.1, 35.2, 35.3, 35.4, 35.5., 35.6, 35.7, 35.8, 35.9, 36, 37, 38, or 39 kgf / cm 2It could be. In some aspects, the predetermined burst pressure can be within a range formed by selecting any two numbers listed herein, for example, from about 21.1 to about 29, from about 25 to about 29, from about 25.1 to about 29, from about 21 to about 24, from about 25 to about 28.9, from about 24.9 to about 29, from about 25.5 to about 29, from about 26 to about 29, from about 27 to about 29, from about 28 to about 29, from about 25 to about 28.5, from about 24.9 to about 28.9, from about 21 to about 35, from about 25 to about 39, from about 24.9 to about 35.3, from about 25.1 to about 38, from about 25.5 to about 30.1, from about 29 to about 39, from about 26 to about 38, about 27 to about 37 kgf / cm 2 It could be the back.

[0207]

[0208] Non-limiting examples of predetermined burst pressures and unclamping pressures

[0209] The examples of the predetermined burst pressure and unclamping pressure described above are illustrative and non-limiting. As long as the predetermined burst pressure is lower than the unclamping pressure, the predetermined burst pressure and unclamping pressure can be any two numbers provided herein. For example, the predetermined burst pressure can be 10 kgf / cm², and the unclamping pressure can be 100 kgf / cm²; the predetermined burst pressure can be 10 kgf / cm², and the unclamping pressure can be 100 kgf / cm²; the predetermined burst pressure can be 20 kgf / cm², and the unclamping pressure can be 50 kgf / cm²; the predetermined burst pressure can be 30 kgf / cm², and the unclamping pressure can be 40 kgf / cm²; The predetermined burst pressure may be 50 kgf / cm², and the unclamping pressure may be 100 kgf / cm²; The predetermined burst pressure may be 21 kgf / cm², and the unclamping pressure may be 30 kgf / cm²; The predetermined burst pressure may be 25 kgf / cm², and the unclamping pressure may be 30 kgf / cm²; The predetermined burst pressure may be kgf / cm², and the unclamping pressure may be 60 kgf / cm²; The predetermined burst pressure may be 1 kgf / cm², and the unclamping pressure may be 10 kgf / cm²; The predetermined burst pressure may be 15 kgf / cm², and the unclamping pressure may be 20 kgf / cm²; The above predetermined bursting pressure may be 40 kgf / cm², the above unclamping pressure may be 90 kgf / cm², etc.

[0210]

[0211] Examples of form factors, predetermined burst pressures, and unclamping pressures

[0212] The battery provided herein may be a battery having a form factor ratio (defined as the diameter of a cylindrical battery divided by its height, i.e., the diameter (T) to height (H) ratio) of 0.4 or greater. For example, the battery provided herein may be, for example, a 46110 cell (46 mm diameter, 110 mm height, form factor ratio 0.418), a 4875 cell (48 mm diameter, 75 mm height, form factor ratio 0.640), a 48110 cell (48 mm diameter, 110 mm height, form factor ratio 0.436), a 4880 cell (48 mm diameter, 80 mm height, form factor ratio 0.600), a 4680 cell (46 mm diameter, 80 mm height, form factor ratio 0.575), or a 4695 cell (46 mm diameter, 95 mm height, form factor ratio 0.484). In the numbers representing the form factor, the first two numbers represent the diameter of the battery, and the next two or three numbers represent the height of the battery. Batteries having similar form factor ratios may have similar predetermined burst pressures. For example, a battery having a form factor ratio of 0.4 or greater, such as a 46110, 4875, 48110, 4880, 4680, or 4695 cell battery, may have a predetermined burst pressure of about 21 to about 29 kgf / cm. 2, for example 21.1, 21.2, 21.3, 21.4, 21.5, 21.6, 21.7, 21.8, 21.9, 22, 22.1, 22.2, 22.3, 22.4, 22.5, 22.6, 22.7, 22.8, 22.9, 23, 23.1, 23.2, 23.3., 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, 25, 25.1, 25.2, 25.3, 25.4, 25.5, 25.6, 25.7, 25.8, 25.9, 26, 26.1, 26.2, 26.3, 26.4, 26.4, 26.6, 26.7, 26.8, 26.9, 27, 27.1, 27.2, 27.3, 27.4, 27.5, 27.6, 27.7, 27.8, 27.9, 28, 28.1, 28.2, 28.3, 28.4, 28.5, 28.6, 28.7, 28.8, 28.9, or 29 kgf / cm 2 can have; about 29 kgf / cm 2 It can have a greater unclamping pressure, for example about 29.1, 29.2, 29.3, 29.4, 29.5, 29.6, 29.7, 29.8, 29.9, 30, 30.1, 30.2, 30.3, 30.4, 30.5, 30.6, 30.7, 30.8, 30.9, 31, 31.1, 31.2, 31.3, 31.4, 31.5, 31.6, 31.7, 31.8, 31.9, 32, 32.1, 32.2., 32.3, 32.4, 32.5, 32.6, 32.7, 32.8, 32.9, 33, 33.1, 33.2, 33.3, 33.4, 33.5, 33.6, 33.7, 33.8, 33.9, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 kgf / cm 2 , or 50 kgf / cm 2. may have an unclamping pressure of any number greater than. In some aspects, the predetermined burst pressure may be within a range formed by selecting any two numbers provided herein, for example, from about 21.1 to about 29, from about 25 to about 29, from about 25.1 to about 29, from about 21 to about 24, from about 25 to about 28.9, from about 24.9 to about 29, from about 25.5 to about 29, from about 26 to about 29, from about 27 to about 29, from about 28 to about 29, from about 25 to about 28.5, from about 24.9 to about 28.9 kgf / cm 2 and the unclamping pressure may be within a range formed by selecting any two numbers provided herein, for example, about 29.1 to about 30.4, about 30.1 to about 34, about 35 to about 40, about 40 to about 45 kgf / cm 2 It could be the back.

[0213]

[0214] Internal pressure that ruptures the rupture notch

[0215] When the internal pressure reaches a predetermined burst pressure, the burst notch (41, 201) bursts to create an opening in the cap plate (40) or the bottom plate. The opening is within the area of ​​the cap plate (40) or the bottom plate that was surrounded by the burst notch (41, 201) before the burst. Since the predetermined burst pressure is lower than the unclamping pressure, when the internal pressure reaches the predetermined burst pressure, the internal pressure is lower than the unclamping pressure. Therefore, when the burst notch (41, 201) bursts, the cap plate (40) is not unclamped and is still crimped to the end of the battery can (20). In the side view shown in Fig. 1A, the burst notch (41) bursts to create an opening in the cap plate (40) at the first end (E1). In the side view shown in FIG. 1b, the rupture notch (201) ruptures to create an opening in the bottom plate of the first end (E1).

[0216]

[0217] Discharge of jelly roll electrode assembly

[0218] The predetermined burst pressure is designed to be sufficient to generate an explosive force. When the internal pressure reaches the predetermined burst pressure, the internal pressure generates an explosive force to eject at least a portion of the jellyroll electrode assembly (10) through the opening in the cap plate (40) or the bottom plate created by the rupture of the rupture notch. In some aspects, the explosive force does not damage other parts of the battery or create other openings in the cylindrical body of the battery. Therefore, in the aspect illustrated in FIG. 1A, the jellyroll electrode assembly is ejected only through the opening in the cap plate (40). In the aspect illustrated in FIG. 1B, because the predetermined burst pressure is lower than the unclamping pressure, when the internal pressure reaches the predetermined burst pressure to rupture the rupture notch (201), the cap plate (40) is not unclamped but remains clamped to the end (E2) of the battery can (20). Therefore, the jellyroll electrode assembly is ejected only through the opening in the bottom plate. In addition, since the area of ​​the cap plate 40 or the bottom plate surrounded by the rupture notch (41, 201) is located at the center of the cap plate (40) or the bottom plate, the opening is also located at the center of the cap plate (40) or the bottom plate. Therefore, when the jellyroll electrode assembly is discharged, the inner part of the jellyroll or the part close to the winding center C is discharged before the outer part of the jellyroll surrounding the inner part inside the cylindrical body before it is ruptured as shown in FIG. 4, and the innermost part or the central part of the jellyroll leads the discharge.

[0219]

[0220] Discharge distance

[0221] As illustrated in FIG. 2, the ejected portion of the jelly roll extends in a telescoping manner along the winding axis and moves away from the first end (E1). The first end (E0) of the ejected portion can reach a distance of about 1 / 4 or more of the length of the cylindrical body of the battery along the winding axis. As illustrated in FIG. 2, the distance between the end (E0) of the ejected electrode assembly furthest from the battery can (20) and the end (E1) of the battery, or the difference between t1 and t2, can be at least 1 / 4 of the length (t2) of the battery can (20). For example, this distance is at least about 0.25, 0.255, 0.26, 0.265, 0.27, 0.275, 0.28, 0.285, 0.29, 0.295, 0.3, 0.35 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95,1.1, 1.125, 1.5, 1.2, 1.225, 1.25, 1.275, 1.3, 1.375, 1.4, 1.45, 1.5, 1.6, 1.7, It can be 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3 times or more. This distance can be within a range formed by selecting any two numbers listed above, and for example, it can be within a range of about 0.25 to about 0.4, about 0.4 to about 1.3, about 1 to about 1.8 times the length (t2) of the battery can (20).

[0222]

[0223] Mass of the extruded portion

[0224] The ejected portion of the jellyroll electrode assembly has a mass that is greater than or equal to about 25% of the total mass of the jellyroll electrode assembly inside the battery can before ejection. For example, the above-mentioned discharged portions are about 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, The ejected portion can have a mass of 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95%. In some aspects, the ejected portion can have a mass within a range formed by selecting any two numbers listed herein, for example, about 25 to about 30, about 25 to about 50, about 25 to about 90, about 30 to about 60, about 40 to about 55, about 45 to about 75, about 50 to about 70, about 55 to about 80, about 60 to about 90% of the total mass of the electrode assembly before ejection. Surprisingly, the ejected portion of the electrode assembly, which accounts for more than about 25% of the total mass as described herein, does not cause additional chemical reactions within the cylindrical body of the battery that could lead to thermal runaway. If more than 25% of the total mass of the electrode assembly is discharged outside the battery, the electrode assembly remaining inside the battery may not be sufficient to sustain the chemical reactions within the battery, leading to thermal runaway. Furthermore, as the jellyroll electrode assembly is discharged, the gases and heat generated inside the battery are also released.Thus, the chemical reactions inside the battery may be partially or completely slowed down or stopped, preventing further decomposition of the electrolyte, the production of more flammable gases that would trigger further reactions inside the battery, and / or the accumulation of more heat.

[0225]

[0226] Factors affecting the discharged portion

[0227] Factors affecting the amount of ejected portion of a jellyroll electrode assembly may include the jellyroll outer diameter size, the jellyroll winding tension, the volume of void space inside the battery can, the size of the rupture opening of the rupture notch, and the characteristics of the readily dissipative collector plate (e.g., number of weld points, collector plate structure, etc.).

[0228]

[0229] No other burst notches or vents

[0230] The battery provided herein may not include any other rupture notches or vents for gas escape. This may prevent gas from escaping through the other rupture notches or vents, and increase the internal pressure to create an explosive force that can expel at least a portion of the jellyroll electrode assembly, which may surprisingly prevent and / or stop thermal runaway.

[0231]

[0232] Minimize or prevent side ruptures

[0233] The side portion of the battery can (20) is designed to maintain a predetermined burst pressure of the burst notch and may have a predetermined side burst pressure necessary to damage the side portion. The side portion may be made of a material or have a thickness and / or shape that requires a side burst pressure greater than the predetermined burst pressure. For example, the side portion may have a thickness in a range of about 0.1 mm to about 0.4 mm, such as 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, or 0.4 mm. In some aspects, the thickness of the side portion can be within a range formed by selecting any two numbers listed herein, for example, from about 0.1 mm to about 0.3 mm, from 0.15 mm to about 0.35 mm, from about 0.1 mm to about 0.3 mm, from about 0.12 mm to about 0.34 mm, from about 0.16 mm to about 0.36 mm, from about 0.2 mm to about 0.4 mm, from about 0.25 mm to about 0.32 mm, from about 0.2 mm to about 0.4 mm, etc. When the internal pressure reaches the predetermined burst pressure, even if the battery explodes and a flame is generated, the explosion does not cause a hole or tear in the side portion of the battery cell, or at least the rupture of the side portion is minimized, and the flame is directed only to one end of the battery as the jellyroll electrode assembly is ejected, so that, for example, in a battery pack including a plurality of batteries provided herein, the flame is not directly transmitted to adjacent adjacent unit cells.

[0234]

[0235] While the aspects presented above, the drawings, and the embodiments below are provided to illustrate the present invention, they are not intended to limit the present invention. It should be readily apparent that those skilled in the art will be able to make various modifications and variations within the scope of the technical aspects of the present invention and the equivalent scope of the claims set forth below.

[0236] yes

[0237] Example 1

[0238] A separator was interposed between the positive and negative plates, and the separator / positive plate / separator / negative plate were laminated in that order. The laminated bodies were wound together to manufacture a jelly-roll type electrode assembly. The positive plate was obtained by coating a slurry on a current collector. The slurry included a nickel, cobalt, manganese, aluminum (NCMA) active material, a carbon nanotube (CNT) conductive material, and a polyvinylidene fluoride (PDVF) binder mixed in a weight ratio of 97.6:0.6:1.8 in N-methyl-2-pyrrolidone (NMP) as a solvent. The negative plate was obtained by coating a slurry on a current collector. The slurry included a graphite and silicon oxide active material, a CNT conductive material, and a carboxymethyl cellulose (CMC) binder mixed in a weight ratio of 98.05:0.05:1.90 in DI water as a solvent. Ceramic-coated polyethylene (PE) was used as the separator. As shown in Fig. 4, the non-coated portions of the positive and negative plates were configured to be folded at each end of the electrode assembly. The manufactured electrode assembly had an outer diameter of 44.5 mm and a height excluding the tabs of 72 mm (same as the width of the separator).

[0239] A sealing tape having a polyurethane substrate with a thickness of 34 ㎛ was attached to the outside of the electrode assembly with an area of ​​35 mm x 134 mm.

[0240] The above electrode assembly was inserted into a cylindrical battery can having a crimping portion and a beading portion and an opening at the first end, as shown in Fig. 1a. An electrolyte was injected, and the opening of the battery can was sealed with a cap plate to manufacture a cylindrical lithium secondary battery. The cap plate was applied under a pressure of 15 kgf / cm. 2 The vent portion configured to burst as described above is included.

[0241] The battery can joint of the first current collecting plate was positioned between the cap plate and the electrode assembly. The first current collecting plate had a thickness of 0.3 mm and a shape as shown in FIG. 15. A connecting portion (33b) having a width of 6 mm was positioned by welding to the bead portion of the battery can. The flame exhaust possible area (A) as shown in FIG. 11 among the opening areas of the first end of the battery can was 34.8%. The ratio of the minimum width (w4) that is closer to the center of the battery can than the maximum width (w3) perpendicular to the diameter of the battery can of the first current collecting plate was 0.9.

[0242] The above cylindrical battery can had 4680 cells with a diameter of 46 mm and a height of 80 mm (form factor ratio 0.575).

[0243] The manufactured lithium secondary battery was subjected to an overcharge test, repeatedly charging and discharging from 0% SOC (state of charge) to 100% SOC at 1.7C. When the vent section ruptured, whether the electrode assembly was ejected through the first end of the battery can, the ejection distance, and whether the side of the battery can was ruptured were evaluated. The results are summarized in Table 3 below.

[0244]

[0245] Example 2

[0246] Example 2 was performed in the same manner as Example 1, except that the sealing tape attached to the outside of the electrode assembly had a polypropylene substrate with a thickness of 30 μm and an area of ​​63 mm x 134 mm.

[0247]

[0248] Example 3

[0249] Example 3 was performed in the same manner as Example 1, except that a first collector plate having a hole (H3) as shown in Fig. 16 was used as the first collector plate positioned between the cap plate and the electrode assembly. The flame exhaust area A was 36.1%, and the width of the connection portion (33b) was 6 mm.

[0250]

[0251] Example 4

[0252] Example 4 was performed in the same manner as Example 1, except that a first collector plate having a hole (H3) as shown in Fig. 16 was used as the first collector plate positioned between the cap plate and the electrode assembly. The flame exhaust area A was 47.2%, and the width of the connection portion (33b) was 4 mm.

[0253]

[0254] Example 5

[0255] Example 5 was performed in the same manner as Example 1, except that a first collector plate having a hole (H3) as illustrated in FIG. 9 was used as the first collector plate positioned between the cap plate and the electrode assembly. The flame exhaust area A was 44.3%, and the width of the connecting portion (33b) was 4 mm. The battery can connecting portion (33a) had a tapered structure with a minimum width equal to the width of the connecting portion (33b). The ratio of the minimum width w4 (4 mm) to the maximum width w3 (14.65 mm) of the tapered structure was 0.27.

[0256]

[0257] Example 6

[0258] Example 6 was performed in the same manner as Example 1, except that a first collector plate having a hole (H3) and a slit (S1) as illustrated in FIG. 10 was used as the first collector plate positioned between the cap plate and the electrode assembly. The flame exhaust possible area A was 44.9%. The width of the connecting portion (33b) was 4 mm. The battery can connecting portion (33a) had a tapered structure with a minimum width equal to that of the connecting portion (33b). The ratio of the minimum width w4 (4 mm) to the maximum width w3 (14.65 mm) of the tapered structure was 0.27.

[0259]

[0260] Example 7

[0261] Example 7 was performed in the same manner as Example 1, except that the thickness of the first collector plate was 0.2 mm and the flame exhaust area A was 34.8%.

[0262]

[0263] Example 8

[0264] Example 8 was performed in the same manner as Example 1, except that the outer diameter of the manufactured electrode assembly was 44.2 mm.

[0265]

[0266] Example 9

[0267] Example 9 was performed in the same manner as Example 1, except that the outer diameter of the manufactured electrode assembly was 44.7 mm.

[0268]

[0269] Example 10

[0270] Example 10: The cap plate is subjected to a pressure of 27 kgf / cm 2 The same method as Example 2 was used, except that the vent portion was configured to burst as described above.

[0271]

[0272] Example 11

[0273] Example 11: The cap plate is subjected to a pressure of 24 kgf / cm 2 The same procedure as Example 2 was followed, except that a vent portion configured to burst was included. Figure 17 is a photograph of an electrode being ejected from the center of the electrode assembly.

[0274]

[0275] Example 12

[0276] Example 12: The cap plate is subjected to a pressure of 21 kgf / cm 2 The same method as Example 2 was used, except that the vent portion was configured to burst as described above.

[0277]

[0278] Example 13

[0279] Example 13: The cap plate is subjected to a pressure of 20 kgf / cm 2 The same method as Example 2 was used, except that the vent portion was configured to burst as described above.

[0280]

[0281] Table 1 below summarizes the vent pressure, sealing tape conditions, and outer diameter of the electrode assembly of the batteries manufactured in Examples 1 to 13, and Table 2 summarizes the current collecting plate structures of the batteries manufactured in Examples 1 to 13.

[0282] Example No. Vent (burst) pressure (kgf / ㎠) Sealing tape Electrode assembly material Area (mm x mm) Thickness (㎛) Outer diameter (mm)115PU35x1343444.5215PP63x1343044.5315PU35x1343444.5415PU35x1343444.5515PU35x1343444.5615PU35x1343444.5715PU35x 1343444.5815PU35x1343444.2915PU35x1343444.71027PP63x1343044.51124PP63x1343044.51221PP63x1343044.51320PP63x1343044.5

[0283] Yes. No. 1st collector plate thickness (mm) Flame discharge area (A) (%) Connection width (mm) Hole taper structure slit 10.3T34.86XXX 20.3T34.86XXX 30.3T36.16OXX 40.3T47.24OXX 50.3T44.34OOX 60.3T44.94OOO 70.2T34.86XXX 80.3T34.86XXX 90.3T34.86XXX 100.3T34.86XXX 110.3T34.86XXX 120.3T34.86XXX 130.3T34.86XXX

[0284] In Tables 1 and 2, X means not present, and O means present.

[0285] Table 3 below shows the discharge distance ratio when the electrode was discharged in an overcharge test in which the batteries of Examples 1 to 13 were repeatedly charged and discharged at a rate of 1.7 C. The discharge distance ratio is the ratio of the distance between the end of the discharged electrode assembly and the second end of the battery can to the distance between the first and second ends of the battery can. The discharge distance is the average value of repeated experiments. If the electrode was not discharged, the side of the battery can was ruptured, and if the side of the battery can was ruptured, it was marked as Fail.

[0286] Yes No. Electrode discharge Discharge distance ratio Result of rupture of the side of the battery can Formation of a spiral structure in the discharge area The center of the electrode assembly rises when discharged 1X-10 / 10ea Fail--2X-4 / 10ea Fail--3X-1 / 3ea Fail--4X-1 / 3ea Fail--5NA-0 / 6ea Fail6X-1 / 6ea Fail--7NA-0 / 3ea Fail--8X-5 / 10ea Fail--9X-9 / 10ea Fail--1002 (160 mm / 80 mm) 0 / 5ea Fail5 / 5ea 5 / 5ea 1101.75 (140 mm / 80 mm) 0 / 5ea Fail5 / 5ea 5 / 5ea 1201.275 (102 mm / 80mm) 1 / 5ea Fail0 / 5ea3 / 5ea13O1.125(90 mm / 80 mm)2 / 2ea Fail0 / 2ea0 / 5ea

[0287] In Table 3, X means non-existence, and O means presence.

[0288] As shown in the experimental results above, Examples 10 to 12 had a vent pressure of 21 kgf / cm2 or more, and a discharge distance ratio of 1.25 times or more. Compared to other examples, the degree of lateral rupture of the battery can was extremely low. In particular, in Examples 10 and 11, when the electrode assembly was discharged, the center of the electrode assembly rose, so that the electrode assembly was discharged in a spiral structure, and no lateral rupture of the battery can occurred at all in each of the five repeated experiments.

[0289] Example 2 confirmed that the degree of side rupture of the battery can was improved by using a polypropylene sealing tape compared to Example 1. Examples 3 and 4 showed improvement in the degree of side rupture of the battery can by designing the flame exhaust area (A) to be relatively large. Examples 5 and 6 showed improvement in the degree of side rupture of the battery can by using a first current collecting plate having a tapered structure. Example 8 showed improvement in the degree of side rupture of the battery can by designing the outer diameter of the electrode assembly to be relatively small. Example 7 showed improvement in the degree of side rupture of the battery can by making the thickness of the first current collecting plate thin.

[0290] [Explanation of symbols]

[0291] 1: Lithium secondary battery

[0292] 2: Pack housing

[0293] 3: Battery pack

[0294] 5: Car

[0295] 10: Electrode assembly

[0296] 11: Negative plate non-conductive part

[0297] 11a: Segmentation

[0298] 12: Bipolar plate non-conductive part

[0299] H1: Winding center hole

[0300] 20: Battery can

[0301] E1: Battery can first end

[0302] E2: Second end of battery can

[0303] E0: Electrode assembly end

[0304] 21: Bidding Department

[0305] 22: Crimping section

[0306] 30: First collector plate

[0307] H2: Collector plate hole

[0308] 31: Support

[0309] 32: Tab joint

[0310] 33: Battery can joint

[0311] 33a: Joint

[0312] 33b: Connection

[0313] H3: Support hole

[0314] S1: Support slit

[0315] 40: Cap plate

[0316] 41, 201: Vent

[0317] G1: Sealing gasket

[0318] 50: Battery terminals

[0319] G2: Insulating gasket

[0320] T1: First electrode terminal

[0321] T2: Second electrode terminal

[0322] P: Second collector plate

[0323] S: Insulator

[0324] 42a: Protrusion

[0325] 42c: Connecting plate

[0326] 45: Lead

[0327] 80: Sealing tape

[0328] H3: Support hole

[0329] 211: Negative plate

[0330] 210: Bipolar plate

[0331] 212: Membrane

[0332] 220: Whole house

[0333] 221: Active material layer

[0334] 222: Ministry of Ignorance

Claims

1. A lithium secondary battery comprising a battery can, an electrode assembly and an electrolyte housed inside the battery can, and a cap plate configured to seal the battery can. The above battery can comprises a first end and a second end opposite to the first end, The above lithium secondary battery has an internal pressure of the battery can of 21 kgf / cm 2 wherein at least a portion of the electrode assembly is configured to be discharged through the first end of the battery can when the above is ideal; A lithium secondary battery, wherein a distance from an end of the electrode assembly located farthest from the battery can to a second end of the battery can after a part of the electrode assembly is discharged through the first end of the battery can is at least 1.25 times the distance between the first end and the second end of the battery can.

2. In claim 1, The above lithium secondary battery a) without or before thermal runaway of the lithium secondary battery; or b) without or before rupture of the side of the battery can. A lithium secondary battery, wherein a portion of the electrode assembly is configured to be discharged through a first end of the battery can.

3. In claim 1, The first end of the above battery can includes a vent portion, or A lithium secondary battery, wherein the cap plate is fixed to the first end of the battery can, and the cap plate includes a vent portion.

4. In claim 4, A lithium secondary battery, wherein the above lithium secondary battery is configured such that a part of the electrode assembly is discharged through the first end of the battery can after breakage of the structure that secures the cap plate to the first end of the battery can or after rupture of the vent portion.

5. In claim 1, The above cap plate includes a vent portion, The above vent part has an internal pressure of 21 kgf / cm 2 A lithium secondary battery configured to rupture in the event of an abnormality.

6. In claim 5, The above vent part has an internal pressure of 25 kgf / cm 2 Exceeding 29 kgf / cm 2 A lithium secondary battery configured to rupture when less than 100% of the rated current is supplied.

7. In claim 1, A lithium secondary battery comprising a first current collecting plate provided between the first end of the battery can and the electrode assembly.

8. In claim 7, A lithium secondary battery, wherein the first collector plate includes a battery can joint having a tapered structure.

9. In claim 7, A lithium secondary battery, wherein the flame exhaust area is 30% to 50% based on the total opening area of ​​the first end of the battery can.

10. In claim 1, A lithium secondary battery having a height-to-diameter ratio of 0.4 or more.

11. In claim 1, The above lithium secondary battery is a lithium secondary battery which is a 46110 cell, a 4875 cell, a 48110 cell, a 4880 cell, a 4680 cell, or a 4695 cell.

12. In claim 1, A lithium secondary battery wherein the above electrode assembly is cylindrical.

13. In claim 1, A lithium secondary battery having a thickness of a side of the battery can of 0.1 mm to 0.4 mm.

14. In claim 1, A lithium secondary battery wherein the electrode assembly is a jelly-roll type electrode assembly in which a positive electrode plate and a negative electrode plate are wound in one direction together with a separator interposed between the positive electrode plate and the negative electrode plate, and a part of the electrode assembly is discharged through the first end of the battery can, and then the electrode assembly has a spiral structure.

15. In claim 14, A lithium secondary battery, wherein a sealing tape containing polypropylene or polyimide is attached to the outermost end of the electrode assembly.

16. In claim 14, The above positive and negative plates each include a non-conductive portion on which an active material layer is not formed, A lithium secondary battery, wherein at least a portion of the non-conductive portion of the positive or negative plate defines an electrode tab.

17. In claim 16, The positive electrode plate uncoated portion and the negative electrode plate uncoated portion are formed along the direction in which the electrode assembly is wound on one end of each of the positive and negative electrode plates, respectively. A first collector plate is coupled to the non-conductive portion of the positive electrode plate, and a second collector plate is coupled to the non-conductive portion of the negative electrode plate. A lithium secondary battery, wherein the first current collecting plate and the second current collecting plate are each connected to an electrode terminal.

18. In claim 17, The above positive and negative electrode plates are processed into a plurality of independently foldable segments, A lithium secondary battery, wherein at least some of the independently bendable plurality of segments are bent toward the winding center of the electrode assembly.

19. In claim 18, At least some of the independently foldable plurality of segments are overlapped on the top of the electrode assembly or on the bottom of the electrode assembly, A lithium secondary battery in which the first collector plate and the second collector plate are joined on a plurality of overlapping segments.

20. A battery pack comprising a lithium secondary battery according to any one of claims 1 to 19.

21. An electric vehicle comprising the battery pack of claim 20 as a power source.

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