Battery cell, battery pack and vehicle comprising battery cell

Abstract

A battery cell according to an embodiment of the present invention may comprise: an electrode assembly; a battery case provided with an opening portion on one side thereof and accommodating the electrode assembly through the opening portion; a battery terminal configured to be electrically connected to the electrode assembly through a closing portion of the battery case disposed on an opposite side of the opening portion; and a current collector including a first coupling portion configured to be electrically coupled to the electrode assembly, a second coupling portion configured to be electrically coupled to the battery terminal, and a bridge portion configured to electrically connect the first coupling portion and the second coupling portion, a cross-sectional area of the bridge portion is 5% or less of a total cross-sectional area of the current collector.

Description

Technical Field

[0001] The present disclosure relates to battery cells, battery packs, and vehicles including the battery cells.

[0002] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2023-0105898 filed on August 11, 2023, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

[0003] This application is based upon and claims the benefit of priority from Korean Patent Application No. 10-2024-0100883 filed on July 30, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. Background Art

[0004] Secondary batteries are easily applicable across product groups and offer electrical characteristics such as high energy density. They are commonly used in electric vehicles (EVs) and hybrid electric vehicles (HEVs) powered by electric drive sources, as well as portable devices. These batteries offer the primary advantage of significantly reducing fossil fuel use and the additional advantage of not producing byproducts associated with energy use. Consequently, they are attracting attention as a new energy source that can improve eco-friendliness and energy efficiency.

[0005] Currently, widely used secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. The operating voltage of the unit secondary battery cell (that is, the unit battery cell) is about 2.5V to 4.5V. Therefore, when an output voltage higher than the operating voltage is required, a battery pack can be configured by connecting multiple battery cells in series. In addition, depending on the required charge and discharge capacity of the battery pack, the battery pack can be configured by connecting multiple battery cells in parallel. Therefore, the number of battery cells included in the battery pack can be set in various ways according to the required output voltage and / or charge and discharge capacity.

[0006] In addition, currently used fuse devices in battery cells include PTC (positive temperature coefficient) thermistors, TCO (thermal circuit breakers), etc. However, as the PTC thermistor or TCO repeatedly operates, its own resistance increases, thereby increasing the overall resistance of the circuit.

[0007] In addition, the above devices are all operated by heat generated by overcurrent. That is, the above devices operate to block the flow of current only when overcurrent flows through the circuit current path due to overcharging, etc. and the temperature rises accordingly.

[0008] Therefore, while the above-mentioned device can operate to prevent overcurrent when a safety threat due to heat generation is imminent, it cannot immediately prevent overcurrent when a factor that could cause a temperature increase occurs. As described above, if the internal pressure increases due to an abnormal temperature increase within the battery cell, and the overcurrent is not prevented within an appropriate time, safety issues such as fire or explosion may arise.

[0009] Furthermore, since these devices operate solely based on temperature, they are difficult to use with high-output battery cells, such as battery packs used in vehicles. Specifically, battery packs for vehicles require high C-efficiency, and therefore generate a correspondingly large amount of heat. However, when exposed to such high-temperature environments, devices such as PTC (positive temperature coefficient) thermistors, TCOs (thermal circuit breakers), and thermal fuses may prematurely operate.

[0010] Therefore, it is necessary to provide a battery cell having a structure that can be used in an environment where high current flows and can cut off the current in advance when an event that may cause a temperature increase occurs (for example, an increase in the internal pressure of the battery cell) before the temperature rises to a level that may cause safety problems. Summary of the Invention

[0011] Technical issues

[0012] The present disclosure aims to solve the problems of the prior art, and thus the present disclosure aims to quickly cut off electrical connection when an overcurrent exceeding a reference value occurs in a battery cell.

[0013] However, the technical problems that the present disclosure seeks to solve are not limited to the above problems, and other problems not mentioned above will be clearly understood by those skilled in the art from the description of the present invention described below.

[0014] Technical Solution

[0015] In one aspect of the present disclosure, a battery cell is provided, comprising: an electrode assembly; a battery case having an opening on one side thereof and configured to accommodate the electrode assembly through the opening; a battery terminal configured to be electrically connected to the electrode assembly through a closed portion of the battery case disposed opposite to the opening; and a current collector comprising a first connecting portion, a second connecting portion, and a bridging portion, the first connecting portion being configured to be electrically connected to the electrode assembly, the second connecting portion being configured to be electrically connected to the battery terminal, the bridging portion being configured to electrically connect the first connecting portion and the second connecting portion, and a cross-sectional area of ​​the bridging portion being configured to be 5% or less of an overall cross-sectional area of ​​the current collector.

[0016] The cross-sectional area of ​​the bridge portion may be configured to be 3% to 5% of the entire cross-sectional area of ​​the current collector.

[0017] The cross-sectional area of ​​the bridge portion may be configured to be 2% to 4% of the overall cross-sectional area of ​​the current collector.

[0018] A plurality of bridge portions may be provided, and a total cross-sectional area of ​​the plurality of bridge portions may be configured to be 5% or less of an entire cross-sectional area of ​​the current collector.

[0019] When an abnormality occurs in the battery cell, the current collector can be melted within about 20 seconds.

[0020] The current collector may include a fuse portion provided in the bridge portion and configured to break when an abnormality occurs in the battery cell.

[0021] The current collector may have a rim portion on outer circumferences of the first coupling portion and the second coupling portion, and the bridge portion may be configured to connect the rim portion and the second coupling portion.

[0022] The first coupling portion and the second coupling portion may be positioned to be spaced apart from each other in a radial direction of the electrode assembly.

[0023] The current collector may have a slit line configured to space the first coupling portion and the second coupling portion apart from each other.

[0024] A battery pack according to the present disclosure may include the battery cell according to the present disclosure.

[0025] A vehicle according to the present disclosure may include a battery cell according to the present disclosure.

[0026] Beneficial effects

[0027] According to one aspect of the present disclosure, when an overcurrent exceeding a reference value occurs in a battery cell, electrical connection may be quickly cut off, thereby ensuring the safety of use of the battery cell.

[0028] In addition, the present disclosure may have various other effects, and these will be described in each embodiment, or description of effects that can be easily inferred by those skilled in the art will be omitted. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the detailed description of the present disclosure, serve to provide further understanding of the technical concept of the present disclosure. Therefore, the present disclosure is not to be construed as being limited to the accompanying drawings.

[0030] Figure 1 is a diagram illustrating a structure of an upper portion of a battery cell according to an embodiment of the present disclosure.

[0031] Figure 2 is a perspective view of a current collector (first current collector) included in a battery cell according to an embodiment of the present disclosure.

[0032] Figure 3 It is along Figure 2 1 is a cross-sectional view taken along line II-II′ in FIG. 1 , which illustrates a state in which a bridge portion is fused when an overcurrent occurs in a current collector (first current collector) included in a battery cell according to an embodiment of the present disclosure.

[0033] Figure 4 is a diagram illustrating that two bridge portions are provided in a current collector (first current collector) included in a battery cell according to another embodiment of the present disclosure.

[0034] Figure 5 is a diagram illustrating that three bridge portions are provided in a current collector (first current collector) included in a battery cell according to another embodiment of the present disclosure.

[0035] Figure 6 is a diagram illustrating that four bridge portions are provided in a current collector (first current collector) included in a battery cell according to another embodiment of the present disclosure.

[0036] Figure 7 It shows that according to Figures 4 to 6 A diagram showing the number and width of the bridge portions in the current collector (first current collector), and whether the bridge portions are blown.

[0037] Figure 8 is a diagram illustrating a current collector (first current collector) included in a battery cell according to another embodiment of the present disclosure.

[0038] Figure 9 is a CT image showing that a bridge portion is fusing when an overcurrent occurs in a current collector (first current collector) included in a battery cell according to another embodiment of the present disclosure.

[0039] Figure 10 It shows that according to Figure 8 The width of the bridge portion in the current collector (first current collector) is a graph showing whether the current collector (first current collector) is blown.

[0040] Figure 11 It shows that Figure 8 Experimental data showing the result of external short circuit when the width of the bridge portion in the current collector (first current collector) is 2.5 mm.

[0041] Figure 12 is a diagram showing whether a current collector (first current collector) included in a battery cell is fused according to a crystal structure of a first electrode of the current collector (first current collector) according to an embodiment of the present disclosure.

[0042] Figure 131 is experimental data showing the result of an external short circuit when the crystal structure of the first electrode in the current collector (first current collector) is SC:PC=5:5 according to an embodiment of the present disclosure.

[0043] Figure 14 is a diagram illustrating a structure of a lower portion of a battery cell according to an embodiment of the present disclosure.

[0044] Figure 15 is a diagram illustrating a battery pack including battery cells according to an embodiment of the present disclosure.

[0045] Figure 16 is a diagram illustrating a vehicle according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0046] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be interpreted as being limited to the general and dictionary meanings, but should be interpreted according to the meanings and concepts corresponding to the technical aspects of the present disclosure based on the principle of allowing the inventor to appropriately define the terms for the best interpretation.

[0047] Therefore, the configurations proposed in the embodiments and drawings of this specification only indicate the most preferred embodiments of the present disclosure and do not represent all technical concepts of the present disclosure, so it should be understood that various equivalents and modifications may be made thereto when an application is filed.

[0048] In addition, the present disclosure also includes various embodiments. Redundant descriptions of substantially the same or similar configurations between the embodiments will be omitted, and descriptions will be made based on their differences.

[0049] First, refer to Figures 1 to 3 A battery cell 1 according to an embodiment of the present disclosure will be described.

[0050] Figure 1 is a diagram showing the structure of the upper portion of a battery cell according to an embodiment of the present disclosure, Figure 2 : is a perspective view of a current collector (first current collector) included in a battery cell according to an embodiment of the present disclosure. Figure 3 It is along Figure 2 1 is a cross-sectional view taken along line II-II′ in FIG. 1 , which illustrates a state in which a bridge portion is fused when an overcurrent occurs in a current collector (first current collector) included in a battery cell according to an embodiment of the present disclosure.

[0051] Reference Figures 1 to 3The battery cell 1 according to an embodiment of the present disclosure may include an electrode assembly 10, a battery case 20, a battery terminal 30, and a current collector (first current collector) 40. The battery cell 1 may be a secondary battery configured to be capable of charge and discharge. The battery cell 1 may be, for example, a cylindrical battery.

[0052] The electrode assembly 10 may include a first electrode having a first polarity, a second electrode having a second polarity opposite to the first polarity, and a separator interposed between the first electrode and the second electrode. The electrode assembly 10 may be configured in a form obtained by winding a laminate including the first electrode, the second electrode, and the separator in one direction. If the electrode assembly 10 is configured in a wound form as described above, a winding center hole 10a may be formed in the winding center.

[0053] The first electrode may include a first uncoated portion 11 as a region not coated with an electrode active material. The first uncoated portion 11 may extend from one end of the first electrode along the winding direction of the electrode assembly 10. Therefore, the first uncoated portion 11 may be provided on a first surface that is substantially perpendicular to the outer surface of the electrode assembly 10.

[0054] The second electrode may include a second uncoated portion 12 (see Figure 14 ). The second uncoated portion 12 may extend from one end of the second electrode along the winding direction of the electrode assembly 10. Therefore, the second uncoated portion 12 may be provided on a second surface (a surface located on the opposite side of the first surface) that is substantially perpendicular to the outer surface of the electrode assembly 10.

[0055] Although not specifically shown in the figure, the first uncoated portion 11 and / or the second uncoated portion 12 may include a plurality of segments formed to be divided along the winding direction of the electrode assembly 10. These segments may be formed by grooves in the first uncoated portion 11 and / or the second uncoated portion 12 to a predetermined depth. The plurality of segments may be bent substantially in the radial direction of the electrode assembly 10. In this case, some segments adjacent to each other in the radial direction may overlap each other.

[0056] The battery case 20 may be configured to accommodate the electrode assembly 10 through an opening formed on one side thereof. The battery case 20 may have a closed portion formed opposite to the opening. The battery case 20 may include a conductive metal. The battery case 20 may be electrically connected to the second electrode of the electrode assembly 10.

[0057] The battery terminal 30 may be configured to be electrically connected to the electrode assembly 10 through a closed portion of the battery housing 20 that is located opposite the opening. The battery terminal 30 may be electrically connected to, for example, a first electrode of the electrode assembly 10. In this case, the battery terminal 30 may serve as a first terminal of the battery cell 1. The battery terminal 30 and the battery housing 20 may have opposite polarities to each other, in which case a first sealing member G1 may be provided between the battery housing 20 and the battery terminal 30 to prevent contact between these components and ensure sealing of the battery housing 20.

[0058] The battery terminal 30 may include a first portion 31 and a second portion 32. The first portion 31 may be configured to be electrically coupled to the current collector 40 within the battery case 20. The first portion 31 may be disposed at a position corresponding to the winding center hole 10a of the electrode assembly 10. The second portion 32 may be exposed to the outside of the battery case 20. The second portion 32 may be located approximately in the center of the enclosed portion of the battery case 20.

[0059] The battery terminal 30 may include a third portion 33 disposed outside the first portion 31. The third portion 33 may be riveted to the closing portion of the battery case 20 to fix the battery terminal 30 to the battery case 20.

[0060] The current collector (first current collector) 40 may be configured to electrically connect the battery terminal 30 and the electrode assembly 10. The current collector 40 may be electrically connected to the first electrode of the electrode assembly 10.

[0061] An insulator may be interposed between the current collector 40 and the inner surface of the closed portion of the battery case 20 to prevent contact between the battery case 20 and the current collector 40 having opposite polarities.

[0062] The current collector 40 may be disposed on one side of the electrode assembly 10. Figure 2 , the current collector 40 may include a first coupling portion 41 , a second coupling portion 42 , and a bridge portion 43 .

[0063] The first coupling portion 41 may be configured to be electrically coupled to the electrode assembly 10. The first coupling portion 41 may be coupled to the first uncoated portion 11 of the electrode assembly 10. The first coupling portion 41 may be coupled to a coupling surface formed by bending the first uncoated portion 11. At least a portion of the first coupling portion 41 may be coupled to the first uncoated portion 11 in a region where the number of overlapping layers of the segments in the first uncoated portion 11 is the largest.

[0064] The second coupling portion 42 may be electrically coupled to the first portion 31 of the battery terminal 30. The second coupling portion 42 may be welded to the first portion 31 of the battery terminal 30 by a welding tool inserted through the winding center hole 10a of the electrode assembly 10 or by laser irradiated through the winding center hole 10a.

[0065] The bridge portion 43 may be configured to electrically connect the first coupling portion 41 and the second coupling portion 42. A plurality of first coupling portions 41 may be provided along the circumferential direction of the battery cell 1. In this case, a plurality of bridge portions 43 may also be provided.

[0066] Furthermore, when an overcurrent exceeding a reference value occurs in the battery cell 1, the current collector 40 can be induced to disconnect the bridge portion 43. The external short-circuit test is a key safety assessment test. Therefore, when an external short circuit occurs, the current collector 40 can be induced to fuse itself, thereby minimizing fire in the battery cell 1.

[0067] To this end, the bridging portion 43 may be formed to have a smaller cross-sectional area than the first coupling portion 41. For example, the bridging portion 43 may be formed to have at least one of a width W or a thickness h smaller than the first coupling portion 41. That is, the volume of the bridging portion 43 may be configured to be smaller than the volume of the first coupling portion 41.

[0068] In addition, the bridge portion 43 of the current collector 40 included in the battery cell 1 according to an embodiment of the present disclosure may be configured to have a cross-sectional area that is 50% or less of that of the current collector included in a conventional battery cell.

[0069] In addition, according to the present disclosure, the cross-sectional area of ​​the bridge portion 43 may be configured to be 5% or less of the overall cross-sectional area of ​​the current collector 40. Here, the overall cross-sectional area of ​​the current collector 40 may refer to the area inside the outermost boundary of the current collector 40. In addition, the cross-sectional area of ​​the bridge portion 43 may be defined as (the length d of the bridge portion 43)*(the width W of the bridge portion 43).

[0070] In addition, the volume of the bridge portion 43 can be configured to be 5% or less of the entire volume of the current collector 40. Here, the volume of the bridge portion 43 can be defined as (the length d of the bridge portion 43) * (the width W of the bridge portion 43) * (the thickness h of the current collector 40). For example, the thickness h of the current collector 40 can be configured to be 0.2 mm.

[0071] According to the configuration of the above-described implementation of the present disclosure, when a battery cell 1 experiences an abnormality, the current collector 40 can fuse itself without causing a fire or short circuit. Furthermore, when an overcurrent occurs in the battery cell 1, the current collector 40 can quickly disconnect itself to quickly block the overcurrent. Therefore, the safety of the battery cell 1 can be ensured.

[0072] As a more specific example, the cross-sectional area of ​​the bridge portion 43 may be configured to be 3% to 5% of the entire cross-sectional area of ​​the current collector 40. In this case, the energy density of the battery cell 1 may be approximately 120Wh or greater.

[0073] Alternatively, the cross-sectional area of ​​the bridge portion 43 may be configured to be 2% to 4% of the entire cross-sectional area of ​​the current collector 40. In this case, the energy density of the battery cell 1 may be approximately 99Wh to 120Wh.

[0074] In addition, it is preferable that the cross-sectional area of ​​the bridge portion 43 is 2% or more of the entire cross-sectional area of ​​the current collector 40. This is to minimize the resistance that may increase as the cross-sectional area of ​​the bridge portion 43 decreases.

[0075] In addition, refer to Figure 2 and Figure 3 , the current collector 40 may have a fusion portion F. The fusion portion F may be configured to rupture when an abnormality occurs in the battery cell 1. That is, if an overcurrent occurs in the battery cell 1, the fusion portion F may be induced to rupture.

[0076] The fuse portion F may be provided in the bridge portion 43. According to the configuration of the above-described implementation of the present disclosure, the fuse portion F that is disconnected when an overcurrent occurs in the battery cell 1 may be provided at the connection portion between the second coupling portion 42 and the bridge portion 43 of the current collector 40, so as to partially increase the resistance in the path of a large amount of current flowing in or out of the battery terminal 30 through the battery terminal 30, thereby more effectively inducing the current collector 40 to rupture.

[0077] In particular, the fuse portion F may be provided at a connection portion between the bridge portion 43 and the second coupling portion 42. Furthermore, the fuse portion F may be provided in a portion of the bridge portion 43 closer to the second coupling portion 42.

[0078] According to the configuration of the above-described implementation of the present disclosure, when an abnormal situation occurs in the battery cell 1, the second coupling portion 42 and the bridging portion 43 are connected, and the portion where heat is most concentrated in the current collector 40 may be broken. As a result, the electrical connection of the battery cell 1 can be quickly cut off, thereby ensuring the safety of the battery cell 1 during use.

[0079] Figure 4 is a diagram showing that two bridge portions are provided in a current collector (first current collector) included in a battery cell according to another embodiment of the present disclosure, Figure 5 is a diagram showing that three bridge portions are provided in a current collector (first current collector) included in a battery cell according to another embodiment of the present disclosure, and Figure 6: is a diagram showing that four bridge portions are provided in a current collector (first current collector) included in a battery cell according to another embodiment of the present disclosure. Figure 7 It shows that according to Figures 4 to 6 A diagram showing the number and width of the bridge portions in the current collector (first current collector), and whether the bridge portions are blown.

[0080] Reference Figures 4 to 6 , a plurality of bridge portions 43 may be provided. The bridge portions 43 may be provided along the circumferential direction of the electrode assembly 10. In addition, the plurality of bridge portions 43 may be configured to have the same width W. Alternatively, at least some of the plurality of bridge portions 43 may be configured to have different widths W.

[0081] The plurality of bridge portions 43 may have diversified cross-sectional areas through various combinations of the number of bridge portions 43 and widths W. However, the total cross-sectional area of ​​the plurality of bridge portions 43 may be configured to be 5% or less of the overall cross-sectional area of ​​the current collector 40 .

[0082] Will refer to Figure 7 as well as Figures 4 to 6 Fusing according to the number and width W of the bridge portions 43 is described.

[0083] like Figure 4 As shown in the embodiment of FIG, two bridging portions 43 may be provided. In this case, referring to Figure 6 The width W of the bridge portion 43 may be configured to be approximately 1.5 mm. Alternatively, the width W of the bridge portion 43 may be configured to be approximately 3.0 mm. Alternatively, the width W of the bridge portion 43 may be configured to be approximately 4.5 mm. Alternatively, the width W of the bridge portion 43 may be configured to be approximately 6.0 mm.

[0084] exist Figure 5 In the embodiment shown, three bridge portions 43 may be provided. In this case, reference is made to Figure 6 , the width W of the bridge portion 43 can be configured to be approximately 1.5 mm. In addition, the width W of the bridge portion 43 can be configured to be approximately 3.0 mm.

[0085] exist Figure 6 In the embodiment shown, four bridge portions 43 may be provided. In this case, reference is made to Figure 6 , the width W of the bridge portion 43 can be configured to be approximately 1.5 mm. In addition, the width W of the bridge portion 43 can be configured to be approximately 3.0 mm.

[0086] That is to say, referring to Figure 6If the total cross-sectional area of ​​the plurality of bridge portions 43 is configured to be 5% or less of the overall cross-sectional area of ​​the current collector 40, the current collector 40 can be induced to fuse. On the other hand, it can be seen that if the total cross-sectional area of ​​the plurality of bridge portions 43 exceeds 5% of the overall cross-sectional area of ​​the current collector 40, the current collector 40 cannot fuse well, thereby causing fire.

[0087] In addition, the cross-sectional area of ​​the fusion portion F ( Figure 3 The area indicated by A in FIG. 4 may be defined as (the width W of the bridge portion 43)*(the thickness h of the current collector 40). The fuse portion F may be provided in each bridge portion 43. In this case, referring to Figure 7 It can be seen that no matter how the number and width W of the bridge portion 43 are combined, if the sum of the cross-sectional areas of the fuse portion F is 2.4 mm 2 or smaller, effective fusing can be ensured.

[0088] In particular, the cross-sectional area of ​​the fusion portion F can be configured to be 1.8 mm 2 Or smaller. In addition, the cross-sectional area of ​​the fuse portion F can be configured to be 1.2mm 2 Or smaller. In addition, the cross-sectional area of ​​the fuse portion F can be configured to be 0.9mm 2 Or smaller. In addition, the cross-sectional area of ​​the fuse portion F can be configured to be 0.6mm 2 or smaller.

[0089] In addition, if an abnormality occurs in the battery cell 1, the current collector 40 may be fused within about 20 seconds. Preferably, the current collector 40 may be fused within about 15 seconds. Figure 7 , it can be seen that if the total cross-sectional area of ​​the plurality of bridge portions 43 is configured to be 5% or less of the overall cross-sectional area of ​​the current collector 40 , melting is performed within about 20 seconds, thereby preventing fire.

[0090] Figure 8 is a diagram showing a current collector (first current collector) included in a battery cell according to another embodiment of the present disclosure, Figure 9 is a CT image showing a bridge portion being melted when an overcurrent occurs in a current collector (first current collector) included in a battery cell according to another embodiment of the present disclosure. In addition, Figure 10 It shows that according to Figure 8 The width of the bridge portion in the current collector (first current collector) is a diagram showing whether the current collector (first current collector) is blown.

[0091] Figure 11 It shows that Figure 8 Experimental data showing the results of external short circuit when the width of the bridge portion in the current collector (first current collector) is 2.5 mm.

[0092] In addition, refer to Figure 2 and Figure 8 , the current collector 40 may have a rim portion 44 positioned on the outer circumference of the first coupling portion 41 and the second coupling portion 42. In this case, the bridge portion 43 may be configured to connect the rim portion 44 and the second coupling portion 42.

[0093] As shown in the configuration of the above-described implementation of the present disclosure, if the first coupling portion 41 and the second coupling portion 42 are indirectly connected via the edge portion 44 rather than being directly connected to each other, it is possible to disperse the impact applied to the battery cell 1. That is, it is possible to minimize the transfer of an impact applied to the welded portion of the first coupling portion 41 to the welded portion of the second coupling portion 42, and it is also possible to minimize the transfer of an impact applied to the welded portion of the second coupling portion 42 to the first coupling portion 41.

[0094] In addition, in the current collector 40, the first and second coupling portions 41 and 42 may be positioned to be spaced apart from each other in the radial direction of the electrode assembly 10. That is, an empty space may be formed between the first and second coupling portions 41 and 42 in the radial direction.

[0095] In particular, Figure 8 In the illustrated embodiment, the current collector 40 may have a slit line 45. The slit line 45 may be formed to perforate the current collector 40. That is, the slit line 45 may be formed to perforate the current collector 40, which has a substantially flat circular plate shape. The first coupling portion 41, the second coupling portion 42, and the bridge portion 43 of the current collector 40 may be formed by the slit line 45. In this case, the first coupling portion 41 and the second coupling portion 42 may be spaced apart from each other in the radial direction by the slit line 45. In addition, the first coupling portion 41 and the bridge portion 43 may be spaced apart from each other in the circumferential direction by the slit line 45.

[0096] In this case, when a structure is applied in which the components of the current collector 40 are distinguished by slit lines 45, a complex process of forming the components (i.e., the first coupling portion 41, the second coupling portion 42, and the bridge portion 43) is not required, and the current collector 40 can be manufactured more easily by simply forming cutting lines on the metal plate. As a result, the manufacturing process of the current collector 40 can be simplified, thereby improving productivity or workability when manufacturing the battery cell 1.

[0097] Likewise, in Figure 8 In the illustrated embodiment, the cross-sectional area of ​​the bridge portion 43 may be configured to be 5% or less of the overall cross-sectional area of ​​the current collector 40 .

[0098] More specifically, the width W of the bridge portion 43 may be configured to be approximately 3.0 mm. In this case, the total cross-sectional area of ​​the fuse portion F may be 2.4 mm. 2 or smaller. Figure 10 As shown in the experimental results in , it can be seen that if the width W of the bridge portion 43 is configured to be about 3.0 mm, effective fusing is performed within 20 seconds during the external short circuit test of the battery cell 1 .

[0099] For example, the width W of the bridge portion 43 may be configured to be approximately 2.75 mm. In this case, the sum of the cross-sectional areas of the fuse portions F may be 2.2 mm. 2 or smaller.

[0100] Preferably, the width W of the bridge portion 43 may be configured to be approximately 2.5 mm. In this case, the sum of the cross-sectional areas of the fuse portions F may be 2.0 mm. 2 or smaller.

[0101] like Figure 10 and Figure 11 As shown in the experimental results in FIG, it can be seen that if the width W of the bridge portion 43 is configured to be about 2.5 mm, effective fusing is performed during the external short circuit test of the battery cell 1. In this case, the fusing time of the bridge portion 43 can be about 13.5 seconds, which is within about 20 seconds.

[0102] Therefore, refer to Figure 10 and Figure 11 , it can be seen that even in the current collector 40 equipped with the slit line 45 , when the total cross-sectional area of ​​the plurality of bridge portions 43 is configured to be 5% or less of the overall cross-sectional area of ​​the current collector 40 , melting occurs within approximately 20 seconds, thereby avoiding fire.

[0103] Figure 12 : is a diagram showing whether a current collector (first current collector) included in a battery cell is fused according to the crystal structure of the first electrode of the current collector (first current collector) according to an embodiment of the present disclosure. In addition, Figure 13 1 is experimental data showing the result of an external short circuit when the crystal structure of the first electrode in the current collector (first current collector) is SC:PC=5:5 according to an embodiment of the present disclosure.

[0104] As an example, the crystal structure of the first electrode may be configured as 100% single crystal (SC). Figure 12 , it can be seen that if the crystal structure of the first electrode is 100% SC, melting occurs within 15 seconds or less in all cases, so that no fire occurs.

[0105] As another example, the crystal structure of the first electrode may be configured as a mixture of single crystal (SC) and polycrystalline (PC). For example, the crystal structure of the first electrode may be configured as single crystal (SC): polycrystalline (PC) = 5:5. In this case, referring to Figure 12 , it can be seen that in all cases, melting occurs within 15 seconds or less, so that no fire occurs.

[0106] also, Figure 12 and Figure 13 The experiment in FIG was performed using a current collector 40 including a bridge portion 43 having a width W of 2.5 mm. That is, as in the embodiment of the present disclosure, when the cross-sectional area of ​​the bridge portion 43 is 5% or less of the entire cross-sectional area of ​​the current collector 40, even if the crystal structure of the first electrode is configured as a mixture of single crystal and polycrystalline, melting can occur, and thus ignition does not occur, just like when it is configured as only single crystal.

[0107] Figure 14 is a diagram illustrating a structure of a lower portion of a battery cell according to an embodiment of the present disclosure.

[0108] Reference Figure 14 , the battery cell 1 according to an embodiment of the present disclosure may include a current collector (second current collector) 50. The current collector 50 may be configured to electrically connect the electrode assembly 10 and the battery case 20. The current collector 50 may be electrically connected to the second electrode of the electrode assembly 10. The current collector 50 may be electrically coupled to the second uncoated portion 12 provided on the second surface of the electrode assembly 10. The current collector 50 may be electrically coupled to the inner surface of the battery case 20. The current collector 50 may be electrically coupled to the curling portion 21 formed by pressing the outer circumference of the battery case 20.

[0109] The battery cell 1 may include a cap 60. The cap 60 may be configured to close the opening of the battery case 20. The cap 60 may be fixed by a crimping portion 22 configured to extend and bend from the crimping portion 21 of the battery case 20 and surround the edge of the cap 60. A sealing member (second sealing member) G2 may be interposed between the cap 60 and the inner surface of the battery case 20. The cap 60 may include a vent portion 61 configured to be weaker than the remaining area. The vent portion 61 may be configured by partially reducing the thickness of the cap 60. The vent portion 61 may be configured to rupture when the internal pressure of the battery cell 1 increases to a predetermined pressure or higher.

[0110] Figure 15 is a diagram illustrating a battery pack including battery cells according to an embodiment of the present disclosure.

[0111] Reference Figure 15, a battery pack 3 according to an embodiment of the present disclosure may include a battery cell 1 according to an embodiment of the present disclosure and a battery pack case 2 that accommodates the battery cell 1. A plurality of battery cells 1 may be provided, and the plurality of battery cells 1 may be electrically connected to each other. The battery cell 1 of the present disclosure may be configured such that the battery terminal 30 and the enclosed portion of the battery case 20 serve as a first electrode terminal and a second electrode terminal, respectively. Therefore, a plurality of battery cells 1 may be arranged in the battery pack case 2 such that the terminals 30 of all the battery cells 1 point upward, thereby establishing an electrical connection at the upper portion of the battery cell 1.

[0112] Figure 16 is a diagram illustrating a vehicle according to an embodiment of the present disclosure.

[0113] Reference Figure 16 The vehicle 5 according to the embodiment of the present disclosure may include the battery pack 3 according to the embodiment of the present disclosure. The vehicle 5 may be configured to travel by receiving power from the battery pack 3. The vehicle 5 may be, for example, an electric vehicle or a hybrid vehicle.

[0114] As described above, although the present disclosure has been described with reference to limited embodiments and drawings, the present disclosure is not limited thereto, and those skilled in the art to which the present disclosure pertains may make various modifications and variations within the technical idea of ​​the present disclosure and the equivalent scope of the claims to be described below.

Claims

1. A battery cell, comprising: electrode assembly; a battery case having an opening on one side thereof and configured to accommodate the electrode assembly through the opening; a battery terminal configured to be electrically connected to the electrode assembly through a closed portion of the battery case disposed opposite the opening; as well as a current collector comprising a first coupling portion, a second coupling portion, and a bridging portion, wherein the first coupling portion is configured to be electrically coupled to the electrode assembly, the second coupling portion is configured to be electrically coupled to the battery terminal, and the bridging portion is configured to electrically connect the first coupling portion and the second coupling portion. The cross-sectional area of ​​the bridge portion is configured to be 5% or less of the entire cross-sectional area of ​​the current collector.

2. The battery cell according to claim 1, in, The cross-sectional area of ​​the bridge portion is configured to be 3% to 5% of the entire cross-sectional area of ​​the current collector.

3. The battery cell according to claim 1, in, The cross-sectional area of ​​the bridge portion is configured to be 2% to 4% of the entire cross-sectional area of ​​the current collector.

4. The battery cell according to claim 1, in, The current collector comprises: A fuse portion is provided in the bridging portion and is configured to break when an abnormality occurs in the battery cell.

5. The battery cell according to claim 1, in, A plurality of the bridge portions are provided, and The total cross-sectional area of ​​the plurality of bridge portions is configured to be 5% or less of the overall cross-sectional area of ​​the current collector.

6. The battery cell according to claim 1, in, When an abnormality occurs in the battery cell, the current collector is fused within about 20 seconds.

7. The battery cell according to claim 1, in, The current collector has a rim portion located on outer circumferences of the first coupling portion and the second coupling portion, and Wherein, the bridging portion is configured to connect the edge portion and the second coupling portion.

8. The battery cell according to claim 1, in, The first coupling portion and the second coupling portion are positioned to be spaced apart from each other in a radial direction of the electrode assembly.

9. The battery cell according to claim 8, in, The current collector has a slit line configured to space the first coupling portion and the second coupling portion apart from each other.

10. A battery pack comprising the battery cell according to any one of claims 1 to 9.

11. A vehicle comprising the battery cell according to any one of claims 1 to 9.

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