Battery cell, battery pack, and vehicle that includes the same.

Abstract

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

Description

1 / 24 Battery cell, battery pack, and vehicle that includes the same. FIELD OF TECHNIQUE

[0001] The present invention relates to a battery cell, a battery pack and a vehicle that includes the same.

[0002] This application is based on and claims priority from Korean Patent Application Number 10-2023-0105898, filed on August 11, 2023 with the Korean Intellectual Property Office, the description of which is incorporated herein in its entirety by reference.

[0003] This application is based on and claims priority from Korean Patent Application Number 10-2024-0100883, filed on July 30, 2024 with the Korean Intellectual Property Office, the description of which is incorporated herein in its entirety by reference. BACKGROUND OF THE TECHNIQUE

[0004] Secondary batteries, which are easy to apply depending on the product group and have electrical characteristics such as high energy density and the like, are commonly used in electric vehicles (EVs) or hybrid electric vehicles (HEVs) that are powered by an electric drive source, as well as in portable devices. These secondary batteries are attracting attention as a new energy source to improve sustainability and energy efficiency due to the main advantage of dramatically reducing the use of fossil fuels and another advantage of not generating byproducts resulting from energy use.

[0005] Commonly used secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and similar batteries. The operating voltage of this unitary secondary battery cell, i.e., the unitary battery cell, is approximately 2.5 V to 4.5 V. Therefore, when a higher output voltage than this is applied, Petition 870250080384, dated 08 / 09 / 2025, page 8 / 53 If required, a battery pack can be configured by connecting multiple battery cells in series. Additionally, a battery pack can be configured by connecting multiple battery cells in parallel, depending on the required charge / discharge capacity of the battery pack. Consequently, the number of battery cells included in the battery pack can be defined in various ways, depending on the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, the fuse devices currently used in battery cells include PTC (positive temperature coefficient) thermistors, TCOs (thermal circuit breakers), and the like. However, as PTC thermistors or TCOs are repeatedly operated, their own resistance increases, thereby increasing the total resistance of the circuit.

[0007] Furthermore, the above devices are all operated by heat generated due to overcurrent. That is, the above devices operate to block the current flow only when overcurrent flows through the circuit current path due to overload or similar, so that the temperature increases accordingly.

[0008] Therefore, the above devices can operate to block overcurrent after a safety-threatening situation due to heat generation is imminent, but are unable to block overcurrent immediately when a cause that could increase the temperature occurs. As described above, in the case where internal pressure increases due to abnormal temperature increases within the battery cell, if the overcurrent fails to be blocked within an appropriate time, safety problems such as ignition or explosion may occur.

[0009] In addition, as the above devices simply operate Petition 870250080384, dated 09 / 08 / 2025, p. 9 / 53 3 / 24 ram depending on the temperature, these are difficult to use in battery cells that exhibit high efficiency, such as battery packs used in vehicles. That is, battery packs for vehicles require a high C-rate and result in a large amount of heat being generated accordingly. However, devices such as PTC (positive temperature coefficient) thermistors, TCOs (thermal circuit breakers), and thermal fuses are likely to operate very early when exposed to such high-temperature environments.

[0010] Therefore, it is necessary to provide a battery cell that has a structure that can be used in environments where high current flows and that can cut off the current prematurely when an event that could cause a temperature increase (for example, an increase in the internal pressure of the battery cell) occurs before the temperature rises to a level that could cause a safety problem. DESCRIPTION TECHNICAL PROBLEM

[0011] The present description is designed to solve the problems of the relevant technique and, therefore, the present description is intended to quickly cut off the electrical connection when an overcurrent exceeding a reference value occurs in a battery cell.

[0012] However, the technical problems that the present description seeks to solve are not limited to the problems mentioned above, and other problems not mentioned above will be clearly understood by those skilled in the art of the invention described below. TECHNICAL SOLUTION

[0013] In one aspect of the present description, a battery cell is provided comprising: an electrode assembly; a battery housing having an opening on one side thereof and configured to accommodate the electrode assembly through the opening; a terminal of Petition 870250080384, dated 08 / 09 / 2025, page 10 / 53 4 / 24 battery configured to be electrically connected to the electrode assembly through a closed portion provided opposite the battery housing opening; and a current collector comprising 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, and the cross-sectional area of ​​the bridge portion may be configured to be 5% or less of the entire cross-sectional area of ​​the current collector.

[0014] The cross-sectional area of ​​the bridge portion can be configured to be 3% to 5% of the entire cross-sectional area of ​​the current collector.

[0015] The cross-sectional area of ​​the bridge portion can be configured to be 2% to 4% of the entire cross-sectional area of ​​the current collector.

[0016] A plurality of bridge portions may be provided, and the total cross-sectional area of ​​the plurality of bridge portions may be configured to be 5% or less of the entire cross-sectional area of ​​the current collector.

[0017] A collector current meltdown time can be within approximately 20 seconds when an abnormality occurs in the battery cell.

[0018] The current collector may include a fusion portion provided in the bridge portion and configured to break when an abnormality occurs in the battery cell.

[0019] The current collector may have a ring portion located on the outer circumference of the first coupling portion and the se Petition 870250080384, dated 08 / 09 / 2025, page 11 / 53 5 / 24 second coupling portion, and the bridge portion can be configured to connect the rim portion and the second coupling portion.

[0020] The first coupling portion and the second coupling portion can be positioned to be spaced from each other in a radial direction of the electrode array.

[0021] The current collector may have a slot line configured to space the first coupling portion and the second coupling portion from each other.

[0022] A battery pack according to the present description may include a battery cell according to the present description.

[0023] A vehicle according to the present description may include a battery cell according to the present description. ADVANTAGEOUS EFFECTS

[0024] According to one aspect of the present description, when an overcurrent exceeding a reference value occurs in a battery cell, the electrical connection can be quickly cut, thereby ensuring the safe use of the battery cell.

[0025] In addition, the present description may have several other effects, and these will be described in the respective embodiments, or the description of effects that can be easily inferred by those skilled in the art will be omitted. DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings illustrate a preferred embodiment of the present description and, together with the detailed description of the invention, serve to provide a better understanding of the technical idea of ​​the present description and, therefore, the present description is not to be interpreted as being limited to the drawings.

[0027] Figure 1 is a drawing illustrating the structure of an upper portion of a battery cell, according to an embodiment of Petition 870250080384, dated 08 / 09 / 2025, page 12 / 53 6 / 24 present description.

[0028] 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 description.

[0029] Figure 3 is a cross-sectional view taken along line II-II' in Figure 2, which illustrates the state in which a portion of the bridge is melted when an overcurrent occurs in a current collector (first current collector) included in a battery cell, according to an embodiment of the present description.

[0030] Figure 4 is a drawing that illustrates 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 description.

[0031] Figure 5 is a drawing that illustrates 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 description.

[0032] Figure 6 is a drawing that illustrates 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 description.

[0033] Figure 7 is a drawing that illustrates whether the bridge portions fuse or not, depending on the number and widths of the bridge portions in the current collector (first current collector) in Figures 4 to 6.

[0034] Figure 8 is a drawing illustrating a current collector (first current collector) included in a battery cell, according to another embodiment of the present description.

[0035] Figure 9 is a CT image illustrating a portion of the bridge being fused when an overcurrent occurs in a collector. Petition 870250080384, dated 08 / 09 / 2025, page 13 / 53 7 / 24 current (first current collector) included in a battery cell, according to another embodiment of the present description.

[0036] Figure 10 is a drawing that illustrates whether a current collector (first current collector) melts or not, depending on the widths of the bridge portions in the current collector (first current collector) in Figure 8.

[0037] Figure 11 shows experimental data illustrating the results of an external short circuit if the width of a bridge portion in the current collector (first current collector) in Figure 8 is 2.5 mm.

[0038] Figure 12 is a drawing that illustrates whether a current collector (first current collector) included in a battery cell melts or not, depending on the crystal structure of a first electrode of the current collector (first current collector), according to an embodiment of the present description.

[0039] Figure 13 is experimental data illustrating the result of an external short circuit when a crystal structure of a first electrode in a current collector (first current collector) is SC:PC = 5:5, according to an embodiment of the present description.

[0040] Figure 14 is a drawing illustrating the structure of a lower portion of a battery cell, according to an embodiment of the present description.

[0041] Figure 15 is a drawing illustrating a battery pack that includes a battery cell, according to an embodiment of the present description.

[0042] Figure 16 is a drawing that illustrates a vehicle, according to an embodiment of the present description. BEST WAY

[0043] Hereafter, the preferred embodiments of the present description shall be described in detail with reference to the drawings. Petition 870250080384, dated 09 / 08 / 2025, p. 14 / 53 8 / 24 annexes. Before the description, it should be understood that the terms used in the specification and in the appended claims should not be interpreted as limited to general and dictionary meanings, but interpreted based on the meanings and concepts that correspond to the technical aspects of the present description, based on the principle that the inventor is permitted to define the terms appropriately for the best explanation.

[0044] Therefore, the configurations proposed in the embodiments and drawings of this specification indicate only the most preferable embodiment of the present description and do not represent all the technical ideas of the present description, thus it should be understood that various equivalents and modifications may be made to this at the time of filing the application.

[0045] In addition, the present description includes several modalities. Redundant descriptions of configurations that are substantially the same or similar across different modes will be omitted, and the description will be based on the differences between them.

[0046] First, a battery cell 1 according to an embodiment of the present description will be described with reference to Figures 1 to 3.

[0047] Figure 1 is a drawing illustrating the structure of an upper portion of a battery cell, according to an embodiment of the present description, and 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 description. Furthermore, Figure 3 is a cross-sectional view made along line II-II' in Figure 2, which illustrates the 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 description. Petition 870250080384, dated 08 / 09 / 2025, page 15 / 53 9 / 24

[0048] Referring to Figures 1 to 3, the battery cell 1 according to one embodiment of the present description may include an electrode assembly 10, a battery housing 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 charging and discharging. The battery cell 1 above may be, for example, a cylindrical battery.

[0049] 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 above electrode assembly 10 may be configured in a form obtained by winding a laminate that includes the first electrode, the second electrode, and the separator in one direction. If the electrode assembly 10 is configured in the wound form, as described above, a central winding hole 10a may be formed in a winding center.

[0050] The first electrode may include a first uncoated portion 11, which is an area where the active electrode material is not applied. The first uncoated portion 11 may extend from one end of the first electrode in the winding direction of the electrode assembly 10. Therefore, the first uncoated portion 11 may be provided on a first surface that is approximately perpendicular to the outer surface of the electrode assembly 10.

[0051] The second electrode may include a second uncoated portion 12, which is an area where the electrode active material is not applied (see Figure 14). The second uncoated portion 12 may extend from one end of the second electrode in the winding direction of the electrode assembly 10. Therefore, the second uncoated portion 12 may be provided on a second surface (a surface Petition 870250080384, dated 08 / 09 / 2025, page 16 / 53 10 / 24 located on the opposite side of the first surface) which is approximately perpendicular to the outer surface of the electrode assembly 10.

[0052] Although not specifically shown in the drawing, the first uncoated portion 11 and / or the second uncoated portion 12 may include a plurality of segments formed to be split along the winding direction of the electrode assembly 10. These segments may be formed by notches in the first uncoated portion 11 and / or the second uncoated portion 12 to a predetermined depth. The plurality of segments may be folded approximately in the radial direction of the electrode assembly 10. In this case, some of the segments adjacent to each other in the radial direction may overlap each other.

[0053] The battery housing 20 can be configured to accommodate the electrode assembly 10 through an opening formed on one side thereof. The battery housing 20 may have a closed portion formed opposite the opening. The battery housing 20 may include a conductive metal. The battery housing 20 may be electrically connected to the second electrode of the electrode assembly 10.

[0054] Battery terminal 30 can be configured to be electrically connected to electrode assembly 10 through the closed portion provided opposite the opening of battery housing 20. Battery terminal 30 can be electrically connected, for example, to the first electrode of electrode assembly 10. In this case, battery terminal 30 can function as a first terminal of battery cell 1. Battery terminal 30 and battery housing 20 can have opposite polarities to each other and, in this case, a first sealing member G1 can be provided between battery housing 20 and battery terminal 30 to prevent contact between these components and ensure the sealing of battery housing 20.

[0055] Battery terminal 30 may include a first portion 31 Petition 870250080384, dated 08 / 09 / 2025, page 17 / 53 11 / 24 and a second portion 32. The first portion 31 can be configured to be electrically coupled to the current collector 40 inside the battery housing 20. The first portion 31 can be provided in a position corresponding to the central winding hole 10a of the electrode assembly 10. The second portion 32 can be exposed to the outside of the battery housing 20. The second portion 32 can be located approximately in the center of the closed portion of the battery housing 20.

[0056] Battery terminal 30 may include a third portion 33 provided on the outside of the first portion 31. The third portion 33 may be riveted to the closed portion of the battery housing 20 to secure battery terminal 30 to battery housing 20.

[0057] The current collector (first current collector) 40 can be configured to electrically connect the battery terminal 30 and the electrode assembly 10. The current collector 40 can be electrically connected to the first electrode of the electrode assembly 10.

[0058] An insulator may be interposed between the current collector and the inner surface of the closed portion of the battery housing 20 to prevent contact between the battery housing 20 and the current collector 40, which have opposite polarities.

[0059] The current collector 40 can be arranged on one side of the electrode assembly 10. Referring to Figure 2, the current collector 40 can include a first coupling portion 41, a second coupling portion 42, and a bridging portion 43.

[0060] The first coupling portion 41 can be configured to be electrically coupled to the electrode assembly 10. The first coupling portion 41 can be coupled to the first uncoated portion 11 of the electrode assembly 10. The first coupling portion 41 can be coupled to a coupling surface formed by folding the first uncoated portion 11. At least one Petition 870250080384, dated 08 / 09 / 2025, page 18 / 53 12 / 24 of the first coupling portion 41 can be coupled to the first uncoated portion 11 in an area where the number of overlapping layers of the segments is maximum in the first uncoated portion 11.

[0061] The second coupling portion 42 can be electrically coupled to the first portion 31 of the battery terminal 30. The second coupling portion 42 can be welded to the first portion 31 of the battery terminal 30 by a welding tool inserted through the central winding hole 10a of the electrode assembly 10 or by a laser irradiated through the central winding hole 10a.

[0062] The bridge portion 43 can be configured to electrically connect the first coupling portion 41 and the second coupling portion 42. A plurality of first coupling portions 41 can be provided along the circumferential direction of the battery cell 1. In this case, a plurality of bridge portions 43 can also be provided.

[0063] Meanwhile, the current collector 40 can be induced to break the bridge portion 43 when an overcurrent exceeding a reference value occurs in the battery cell 1. Specifically, the external short-circuit test is one of the important tests in the safety assessment items. Consequently, when an external short circuit occurs, the current collector 40 can be induced to fuse, thereby minimizing the ignition of the battery cell 1.

[0064] To this end, the bridge portion 43 can be formed to have a smaller cross-sectional area than the first coupling portion 41. For example, the bridge portion 43 can 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 bridge portion 43 can be configured to be smaller than the volume of the first coupling portion 41. Petition 870250080384, dated 08 / 09 / 2025, page 19 / 53 13 / 24

[0065] Furthermore, the bridge portion 43 of the current collector 40 included in the battery cell 1, according to an embodiment of the present description, can be configured to have a cross-sectional area of ​​50% or less of the cross-sectional area of ​​the bridge portion of the current collector included in the conventional battery cell.

[0066] Moreover, according to the present description, the cross-sectional area of ​​the bridge portion 43 can be configured to be 5% or less of the entire cross-sectional area of ​​the current collector 40. Here, the entire cross-sectional area of ​​the current collector 40 can indicate the area within the outermost edge of the current collector 40. Furthermore, the cross-sectional area of ​​the bridge portion 43 can be defined as (length d of the bridge portion 43) * (width W of the bridge portion 43).

[0067] Furthermore, 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 (length d of the bridge portion 43) * (width W of the bridge portion 43) * (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.

[0068] According to the configuration implemented above in this description, when battery cell 1 is abnormal, the current collector 40 can fuse and short-circuit without ignition. Furthermore, when an overcurrent occurs in battery cell 1, the current collector 40 itself can quickly break to rapidly block the overcurrent. Consequently, the safety of battery cell 1 can be ensured.

[0069] As a more specific example, the cross-sectional area of ​​the bridge portion 43 can be configured to be 3% to 5% of the entire cross-sectional area of ​​the current collector 40. In this Petition 870250080384, dated 08 / 09 / 2025, page 20 / 53 In the 14 / 24 case, the energy density of battery cell 1 can be approximately 120 Wh or more.

[0070] Alternatively, the cross-sectional area of ​​the bridge portion 43 can 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 battery cell 1 can be approximately 99 Wh to 120 Wh.

[0071] Furthermore, it is preferable that the cross-sectional area of ​​the bridge portion 43 be 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.

[0072] Meanwhile, referring to Figure 2 and Figure 3, the current collector 40 may have a fusion portion F. The fusion portion F may be configured to break when an abnormality occurs in battery cell 1. That is, if an overcurrent occurs in battery cell 1, the fusion portion F may be induced to break.

[0073] The fusion portion F can be provided in the bridge portion 43. According to the configuration implemented above in the present description, the fusion portion F, which must break when an overcurrent occurs in battery cell 1, can be provided in 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 into through the battery terminal 30 or flowing out of the battery terminal 30, by more effectively inducing the breakdown of the current collector 40.

[0074] Specifically, the fusion portion F can be provided in the connection portion between the bridge portion 43 and the second coupling portion 42. Furthermore, the fusion portion F can be provided in Petition 870250080384, dated 08 / 09 / 2025, page 21 / 53 15 / 24 a portion closer to the second coupling portion 42 in the bridge portion 43.

[0075] According to the configuration implemented above in the present description, when an abnormal situation occurs in battery cell 1, the portion where the second coupling portion 42 and the bridge portion 43 are connected and where the heat is most concentrated in the current collector 40 may break. As a result, the electrical connection of battery cell 1 can be quickly cut, thereby ensuring the safety of battery cell 1 in use.

[0076] Figure 4 is a drawing 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 description; Figure 5 is a drawing 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 description; and Figure 6 is a drawing 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 description. Furthermore, Figure 7 is a drawing illustrating whether the bridge portions fuse or not depending on the number and widths of the bridge portions in the current collector (first current collector) in Figures 4 to 6.

[0077] Referring to Figures 4 to 6, a plurality of bridge portions 43 can be provided. The bridge portions 43 can be arranged in the circumferential direction of the electrode array 10. Furthermore, the plurality of bridge portions 43 can be configured to have the same width W. Alternatively, at least some of the plurality of bridge portions 43 can be configured to have different widths W.

[0078] The plurality of bridge 43 portions can diversify the Petition 870250080384, dated 08 / 09 / 2025, page 22 / 53 16 / 24 cross-sectional areas of the bridge portions 43 by various combinations of the number and widths W of the bridge portions 43. However, the total cross-sectional area of ​​the plurality of bridge portions 43 can be configured to be 5% or less of the entire cross-sectional area of ​​the current collector 40.

[0079] The fusion, depending on the number and widths W of the bridge portions 43, will be described with reference to Figure 7, together with Figure 4 to Figure 6.

[0080] Two bridge portions 43 can be provided, as shown in the embodiment of Figure 4. In this case, referring to Figure 7, the width W of the bridge portion 43 can be configured to be approximately 1.5 mm. Furthermore, the width W of the bridge portion 43 can be configured to be approximately 3.0 mm. Furthermore, the width W of the bridge portion 43 can be configured to be approximately 4.5 mm. Furthermore, the width W of the bridge portion 43 can be configured to be approximately 6.0 mm.

[0081] Three bridge portions 43 can be provided in the embodiment illustrated in Figure 5. In this case, referring to Figure 7, the width W of bridge portion 43 can be configured to be approximately 1.5 mm. In addition, the width W of bridge portion 43 can be configured to be approximately 3.0 mm.

[0082] Four bridge portions 43 can be provided in the embodiment illustrated in Figure 6. In this case, referring to Figure 7, 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.

[0083] That is, referring to Figure 7, if the total cross-sectional area of ​​the plurality of bridge portions 43 is configured to be 5% or less of the entire cross-sectional area of ​​the current collector 40, the current collector 40 may be induced to melt. On the other hand, Petition 870250080384, dated 08 / 09 / 2025, page 23 / 53 17 / 24 it can be seen that if the total cross-sectional area of ​​the plurality of bridge portions 43 exceeds 5% of the entire cross-sectional area of ​​the current collector 40, it will not fuse properly, leading to ignition.

[0084] Meanwhile, the cross-sectional area (the area indicated as A in Figure 3) of the fusion portion F can be defined as (width W of the bridge portion 43) * (thickness h of the current collector 40). The fusion portion F can be provided in each bridge portion 43. In this case, referring to Figure 7, it can be seen that, regardless of the combination of the number and widths W of the bridge portions 43, an effective fusion is ensured if the sum of the cross-sectional areas of the fusion portion F is 2.4 mm2 or less.

[0085] Specifically, the cross-sectional area of ​​the fusion portion F can be configured to be 1.8 mm2 or less. Furthermore, the cross-sectional area of ​​the fusion portion F can be configured to be 1.2 mm2 or less. Additionally, the cross-sectional area of ​​the fusion portion F can be configured to be 0.9 mm2 or less. Furthermore, the cross-sectional area of ​​the fusion portion F can be configured to be 0.6 mm2 or less.

[0086] Meanwhile, if an abnormality occurs in battery cell 1, the melting time of current collector 40 may be within approximately 20 seconds. Preferably, the melting time of current collector 40 may be within approximately 15 seconds. Referring to 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 entire cross-sectional area of ​​current collector 40, the melting is performed within approximately 20 seconds, thereby preventing ignition.

[0087] Figure 8 is a drawing illustrating a current collector (first current collector) included in a battery cell, according to another embodiment of the present description. Figure 9 is a Petition 870250080384, dated 08 / 09 / 2025, page 24 / 53 Figure 18 / 24 shows a CT image illustrating 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 description. Additionally, Figure 10 is a drawing illustrating whether a current collector (first current collector) melts or not, depending on the widths of the bridge portions in the current collector (first current collector) in Figure 8.

[0088] Figure 11 shows experimental data illustrating the results of an external short circuit if the width of a bridge portion in the current collector (first current collector) in Figure 8 is 2.5 mm.

[0089] Meanwhile, referring to Figure 2 and Figure 8, the current collector 40 may have a hoop 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 hoop portion 44 and the second coupling portion 42.

[0090] As shown in the above implemented configuration of the present description, if the first coupling portion 41 and the second coupling portion 42 are indirectly connected through the ring portion 44, instead of being directly connected to each other, the impact applied to the battery cell 1 can be dispersed. That is, it is possible to minimize the transfer of the impact applied to the welded portion of the first coupling portion 41 to the welded portion of the second coupling portion 42, and also to minimize the transfer of the impact applied to the welded portion of the second coupling portion 42 to the first coupling portion 41.

[0091] Furthermore, in the current collector 40, the first coupling portion 41 and the second coupling portion 42 can be positioned to be spaced from each other in the radial direction of Petition 870250080384, dated 08 / 09 / 2025, page 25 / 53 19 / 24 electrode assembly 10. That is, an empty space can be formed between the first coupling portion 41 and the second coupling portion 42 in the radial direction.

[0092] Specifically, as in the embodiment shown in Figure 8. The current collector 40 may have a slot line 45. The slot line 45 may be formed to pierce the current collector 40. That is, the slot line 45 may be formed to pierce the current collector 40, which has the shape of a substantially flat and circular plate. 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 slot line 45. In this case, the first coupling portion 41 and the second coupling portion 42 may be spaced from each other by the slot line 45 in the radial direction. Furthermore, the first coupling portion 41 and the bridge portion 43 may be spaced from each other by the slot line 45 in the circumferential direction.

[0093] In this case, when a structure in which the respective components of the current collector 40 are distinguished by the slot line 45 is applied, a complicated process for forming the respective 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 a slot line in a metal plate. As a result, the manufacturing process of the current collector 40 can be simplified, thereby improving productivity or processability when manufacturing the battery cell 1.

[0094] Similarly, in the embodiment shown in Figure 8, the cross-sectional area of ​​the bridge portion 43 can be configured to be 5% or less of the entire cross-sectional area of ​​the current collector 40. Petition 870250080384, dated 08 / 09 / 2025, page 26 / 53 20 / 24

[0095] More specifically, the width W of the bridge portion 43 can be set to be approximately 3.0 mm. In this case, the total cross-sectional area of ​​the fusion portions F can be 2.4 mm2 or less. As shown in the experimental results of Figure 10, it can be seen that if the width W of the bridge portion 43 is set to be approximately 3.0 mm, effective fusion is performed within 20 seconds during an external short-circuit test of battery cell 1.

[0096] For example, the width W of bridge portion 43 can be set to be approximately 2.75 mm. In this case, the sum of the cross-sectional areas of the fusion portions F can be 2.2 mm2 or less.

[0097] Preferably, the width W of the bridge portion 43 can be set to be approximately 2.5 mm. In this case, the sum of the cross-sectional areas of the fusion portions F can be 2.0 mm2 or less.

[0098] As shown in the experimental results in Figures 11 and 12, it can be seen that if the width W of the bridge portion 43 is set to be approximately 2.5 mm, effective fusion is performed during the external short-circuit test of battery cell 1. In this case, the fusion time of the bridge portion 43 can be approximately 13.5 seconds, which is within approximately 20 seconds.

[0099] Therefore, referring to Figures 10 and 11, it can be seen that, in the case where the total cross-sectional area of ​​multiple bridge portions 43 is configured to be 5% or less of the entire cross-sectional area of ​​the current collector 40, even in the current collector 40 equipped with the slot line 45, fusion occurs within approximately 20 seconds, thereby preventing ignition. Petition 870250080384, dated 08 / 09 / 2025, page 27 / 53 21 / 24

[0100] Figure 12 is a drawing illustrating whether a current collector (first current collector) included in a battery cell melts or not, depending on the crystal structure of a first electrode of the current collector (first current collector), according to an embodiment of the present description. Furthermore, Figure 13 shows experimental data illustrating the result of an external short circuit when a crystal structure of a first electrode in a current collector (first current collector) is SC:PC = 5:5, according to an embodiment of the present description.

[0101] As an example, the crystal structure of the first electrode can be configured as a 100% single crystal (SC). Referring to Figure 12, it can be seen that if the crystal structure of the first electrode is a 100% SC, melting occurs in 15 seconds or less in all cases, so no ignition occurs.

[0102] As another example, the crystal structure of the first electrode can be configured as a mixture of a single crystal (SC) and a polycrystal (PC). For example, the crystal structure of the first electrode can be configured as single crystal (SC):polycrystal (PC) = 5:5. In this case, referring to Figure 12, it can be seen that fusion occurs in 15 seconds or less in all cases, so no ignition occurs.

[0103] Meanwhile, the experiments in Figures 12 and 13 were performed with a current collector 40, which includes the bridge portion 43, having a width W of 2.5 mm. That is, as in the embodiment of the present description, in the case where 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 polycrystal, fusion can occur in such a way that no ignition occurs, as in the case where it is configured as only single crystal. Petition 870250080384, dated 08 / 09 / 2025, page 28 / 53 22 / 24

[0104] Figure 14 is a drawing illustrating the structure of a lower portion of a battery cell, according to an embodiment of the present description.

[0105] Referring to Figure 14, battery cell 1, according to one embodiment of the present description, 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 housing 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 a 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 housing 20. The current collector 50 may be electrically coupled to a crimp portion 21 formed by pressing the outer circumference of the battery housing 20.

[0106] Battery cell 1 may include a cover 60. The cover 60 may be configured to close the opening of the battery housing 20. The cover 60 may be secured by a crimping portion 22 that is configured to extend and bend from the crimping portion 21 of the battery housing 20 and encircle the edge of the cover 60. A sealing member (second sealing member) G2 may be interposed between the cover 60 and the inner surface of the battery housing 20. The cover 60 may include a vent portion 61 that is configured to be weaker than the remaining area. The vent portion 61 may be configured to partially reduce the thickness of the cover 60. The vent portion 61 may be configured to rupture when the internal pressure of battery cell 1 increases to a predetermined pressure or higher. Petition 870250080384, dated 08 / 09 / 2025, page 29 / 53 23 / 24

[0107] Figure 15 is a drawing illustrating a battery pack that includes a battery cell, according to an embodiment of the present description.

[0108] Referring to Figure 15, a battery assembly 3, according to one embodiment of the present description, may include a battery cell 1, according to one embodiment of the present description, and an assembly housing 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 one another. The battery cell 1 of the present description may be configured so that the battery terminal 30 and the closed portion of the battery housing 20 function as a first electrode terminal and a second electrode terminal, respectively. Therefore, the plurality of battery cells 1 may be arranged in the assembly housing 2 so that the terminals 30 of all battery cells 1 are directed upwards, thereby establishing the electrical connection in the upper portion of the battery cell 1.

[0109] Figure 16 is a drawing illustrating a vehicle according to an embodiment of the present description.

[0110] Referring to Figure 16, a vehicle 5 according to an embodiment of the present description may include a battery pack 3 according to an embodiment of the present description. The vehicle 5 may be configured to be powered by receiving energy from the battery pack 3. The vehicle 5 may be, for example, an electric vehicle or a hybrid vehicle.

[0111] As described above, although the present description has been described with reference to limited embodiments and designs, the present description is not limited to this, and various modifications and variations are possible within the technical idea of ​​the present description and the scope of equivalence of the claims to be described below by those Petition 870250080384, dated 09 / 08 / 2025, p. 30 / 53 24 / 24 versed in the technique to which the present description refers. Petition 870250080384, dated 09 / 08 / 2025, p. 31 / 53

Claims

1 / 3 CLAIMS 1. Battery cell, characterized in that it comprises: an electrode assembly; a battery housing 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 provided opposite the opening of the battery housing; and a current collector comprising 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, wherein 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. Battery cell according to claim 1, characterized in that 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. Battery cell according to claim 1, characterized in that 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. Battery cell according to claim 1, characterized in that the current collector comprises Petition 870250080384, dated 08 / 09 / 2025, page 32 / 53 2 / 3 a fusion portion provided in the bridge portion and configured to break when an abnormality occurs in the battery cell.

5. Battery cell according to claim 1, characterized in that a plurality of bridge portions is provided, and wherein the total cross-sectional area of ​​the plurality of bridge portions is configured to be 5% or less of the entire cross-sectional area of ​​the current collector.

6. Battery cell according to claim 1, characterized in that the collector current melting time is within approximately 20 seconds when an abnormality occurs in the battery cell.

7. Battery cell according to claim 1, characterized in that the current collector has a hoop portion located on an outer circumference of the first coupling portion and the second coupling portion, and in that the bridge portion is configured to connect the hoop portion and the second coupling portion.

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

9. Battery cell according to claim 8, characterized in that the current collector has a slot line configured to space the first coupling portion and the second coupling portion from each other.

10. Battery pack, characterized in that it comprises a battery cell, as defined in any one of claims 1 to 9. Petition 870250080384, dated 08 / 09 / 2025, page 33 / 53 3 / 3 11. Vehicle, characterized in that it comprises a battery cell, as defined in any one of claims 1 to 9. Petition 870250080384, dated 08 / 09 / 2025, p. 34 / 53

Images