Battery cell, battery pack, and vehicle comprising 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

Battery cells, battery packs and vehicles containing the same

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

[0002] This application claims priority to Korean Patent Application No. 10-2023-0105898, filed on August 11, 2023, and all contents disclosed in the specification and drawings of the said application are incorporated by reference into this application.

[0003] This application claims priority to Korean Patent Application No. 10-2024-0100883, filed on July 30, 2024, and all contents disclosed in the specification and drawings of the said application are incorporated by reference into this application.

[0004] Secondary batteries, which boast high electrical properties such as high energy density and high applicability across a wide range of product categories, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) powered by electrical power sources. These batteries are attracting attention as a new energy source for environmental friendliness and energy efficiency, not only because they can dramatically reduce fossil fuel use, but also because they produce no byproducts from energy use.

[0005] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells, i.e., unit battery cells, is approximately 2.5 V to 4.5 V. Therefore, when a higher output voltage is required, multiple battery cells are connected in series to form a battery pack. Furthermore, depending on the charge / discharge capacity required for the battery pack, a number of battery cells are connected in parallel to form a battery pack. Therefore, the number of battery cells included in the battery pack can be set in various ways depending on the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, fuse devices currently used in battery cells include PTC (positive temperature coefficient thermistor) and TCO (thermal cut-out). However, PTC and TCO have the disadvantage of increasing their internal resistance with repeated operation, thereby increasing the overall resistance of the circuit.

[0007] In addition, all of the above-mentioned devices are operated by heat generation due to overcurrent. In other words, the above-mentioned devices are devices that operate to block the flow of current only when overcurrent is generated in the circuit current path due to overcharging, etc., and this causes the temperature to rise.

[0008] Therefore, for the aforementioned devices, overcurrent protection only begins to occur after overheating has already jeopardized safety. It is not possible to immediately interrupt overcurrent protection when a cause that could cause a temperature rise occurs. Even if internal pressure increases due to an abnormal rise in temperature within the battery cell, if overcurrent protection is not implemented in a timely manner, safety issues such as fire or explosion can occur.

[0009] In addition, since the above-mentioned devices operate simply based on temperature, they are difficult to use in high-power battery cells, such as those used in automotive battery packs. Automotive battery packs require a high c-rate, which inevitably leads to a high amount of heat generation. However, devices such as positive temperature coefficient thermistors (PTC thermistors), thermal cut-outs (TCOs), and thermal fuses can malfunction prematurely when exposed to such high-temperature environments.

[0010] Therefore, a battery cell is required that can be used in an environment where high current flows and that has a structure that can cut off the current in advance when an event that could cause the temperature to rise (e.g., an increase in the internal pressure of the battery cell) occurs before the temperature rises to a level that could cause a safety issue.

[0011] The present invention was created in consideration of the above-described problems, and has as its primary purpose the ability to quickly cut off electrical connection when an overcurrent exceeding a standard value occurs in a battery cell.

[0012] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0013] According to one embodiment of the present invention for solving the above-described problem, a battery cell includes: an electrode assembly; a battery housing having an opening at one side thereof and accommodating the electrode assembly through the opening; a battery terminal configured to be electrically connected to the electrode assembly through a closing portion provided at an opposite side of the opening portion of the battery housing; and a current collector having a first coupling portion configured to be electrically connected to the electrode assembly, a second coupling portion configured to be electrically connected to the battery terminal, and a bridge portion configured to electrically connect between the first coupling portion and the second coupling portion, wherein a 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 above bridge portion may be configured to be 3% or more and 5% or less of the entire cross-sectional area of ​​the entire collector.

[0015] The cross-sectional area of ​​the above bridge portion may be configured to be 2% or more and 4% or less of the entire cross-sectional area of ​​the entire collector.

[0016] The above bridge portion may be provided in multiple numbers, and the total cross-sectional area of ​​the multiple bridge portions may be configured to be 5% or less of the total cross-sectional area of ​​the entire collector.

[0017] When the above battery cell abnormality occurs, the fusing time of the entire collector may be within about 20 seconds.

[0018] The above-mentioned collector is provided in the bridge portion and may be provided with a fusing portion configured to be broken when an abnormality occurs in the battery cell.

[0019] The above-mentioned collector has a rim portion positioned on the outer periphery of the first coupling portion and the 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 may be positioned spaced apart from each other along the radial direction of the electrode assembly.

[0021] The above-mentioned collector may have a slit line configured to mutually space the first coupling portion and the second coupling portion.

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

[0023] A vehicle according to the present invention may include a battery pack according to the present invention.

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

[0025] In addition, the present invention may have various other effects, which will be described in each embodiment configuration, or an explanation of effects that can be easily inferred by a person skilled in the art will be omitted.

[0026] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0027] FIG. 1 is a drawing showing the structure of an upper portion of a battery cell according to one embodiment of the present invention.

[0028] FIG. 2 is a perspective view of a current collector (first current collector) included in a battery cell according to one embodiment of the present invention.

[0029] FIG. 3 is a cross-sectional view taken along line II-II of FIG. 2, which is a drawing of a bridge portion being fused when an overcurrent occurs in a current collector (first current collector) included in a battery cell according to one embodiment of the present invention.

[0030] FIG. 4 is a drawing showing that a current collector (first current collector) included in a battery cell according to another embodiment of the present invention has two bridge sections.

[0031] FIG. 5 is a drawing showing that a current collector (first current collector) included in a battery cell according to another embodiment of the present invention has three bridge sections.

[0032] FIG. 6 is a drawing showing a battery cell according to another embodiment of the present invention having four bridge sections of a current collector (first current collector).

[0033] Fig. 7 is a drawing showing whether fusing occurs according to the number and width of bridge sections in the current collector (first current collector) of Figs. 4 to 6.

[0034] FIG. 8 is a drawing showing a current collector (first current collector) included in a battery cell according to another embodiment of the present invention.

[0035] FIG. 9 is a CT image of a bridge portion being fused when an overcurrent occurs in a current collector (first current collector) included in a battery cell according to another embodiment of the present invention.

[0036] Fig. 10 is a drawing showing whether fusing occurs according to the width of the bridge portion in the collector (first collector) of Fig. 8.

[0037] Fig. 11 is experimental data showing the results of an external short circuit when the width of the bridge portion in the collector (first collector) of Fig. 8 is 2.5 mm.

[0038] FIG. 12 is a drawing showing whether fusing occurs depending on the crystal structure of the first electrode of the current collector (first current collector) included in the battery cell according to one embodiment of the present invention.

[0039] FIG. 13 is experimental data showing the results of an external short circuit when the crystal structure of the first electrode in the current collector (first current collector) according to one embodiment of the present invention is SC:PC = 5:5.

[0040] FIG. 14 is a drawing showing the structure of a lower portion of a battery cell according to one embodiment of the present invention.

[0041] FIG. 15 is a drawing showing a battery pack including a battery cell according to one embodiment of the present invention.

[0042] Fig. 16 is a drawing showing a vehicle according to one embodiment of the present invention.

[0043] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that conforms to the technical spirit of the present invention.

[0044] Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0045] Furthermore, the present invention includes various embodiments. For each embodiment, redundant descriptions of substantially identical or similar components will be omitted, and the differences will be described.

[0046]

[0047] First, a battery cell (1) according to one embodiment of the present invention will be described with reference to FIGS. 1 to 3.

[0048] FIG. 1 is a drawing showing the structure of the upper portion of a battery cell according to one embodiment of the present invention, and FIG. 2 is a perspective view of a current collector (a first current collector) included in the battery cell according to one embodiment of the present invention. In addition, FIG. 3 is a cross-sectional view taken along line II-II' of FIG. 2, which is a drawing showing a state in which a bridge portion is fused when an overcurrent occurs in the current collector (a first current collector) included in the battery cell according to one embodiment of the present invention.

[0049] Referring to FIGS. 1 to 3, a battery cell (1) according to one embodiment of the present invention 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) may be, for example, a cylindrical battery.

[0050] 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 have a form in which a laminate including the first electrode, the second electrode, and the separator is wound in one direction. When the electrode assembly (10) has such a wound form, a winding center hole (10a) may be formed in a region that becomes the winding center.

[0051] The first electrode may include a first uncoated portion (11), which is a region where an electrode active material is not applied. The first uncoated portion (11) may extend from one end of the first electrode along the winding direction of the electrode assembly (10). Accordingly, the first uncoated portion (11) may be provided on a first surface that is approximately perpendicular to the outer circumferential surface of the electrode assembly (10).

[0052] The second electrode may include a second non-coated portion (12), which is a region where an electrode active material is not applied (see FIG. 14). The second non-coated portion (12) may extend from one end of the second electrode along the winding direction of the electrode assembly (10). Accordingly, the second non-coated portion (12) may be provided on a second surface (a surface located on the opposite side to the first surface) that is approximately perpendicular to the outer surface of the electrode assembly (10).

[0053] Although not specifically illustrated in the drawing, the first uncoated portion (11) and / or the second uncoated portion (12) may include a plurality of segments formed by being divided along the winding direction of the electrode assembly (10). These segments may be formed by notching the first uncoated portion (11) and / or the second uncoated portion (12) to a predetermined depth. The plurality of segments may be bent approximately along the radial direction of the electrode assembly (10). In this case, some of the segments adjacent to each other along the radial direction may overlap each other.

[0054] The battery housing (20) may be configured to accommodate an electrode assembly (10) through an opening formed on one side thereof. The battery housing (20) may have a closing portion formed on the opposite side of the opening portion. The battery housing (20) may include a conductive metal. The battery housing (20) may be electrically connected to a second electrode of the electrode assembly (10).

[0055] The battery terminal (30) may be configured to be electrically connected to the electrode assembly (10) through a closing portion provided on the opposite side of the opening portion of the battery housing (20). The battery terminal (30) may be electrically connected, for example, to a first electrode of the electrode assembly (10). In this case, the battery terminal (30) may function as a first terminal of the battery cell (1). The battery terminal (30) and the battery housing (20) may have opposite polarities, and in this 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 to secure sealing of the battery housing (20).

[0056] 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 a current collector (40) on the inside of the battery housing (20). The first portion (31) may be provided 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 housing (20). The second portion (32) may be located approximately at the center of the closed portion of the battery housing (20).

[0057] The above 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 toward the closing portion of the battery housing (20) to secure the battery terminal (30) to the battery housing (20).

[0058] The above 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).

[0059] An insulator (IS) may be interposed between the inner surface of the closed portion of the battery housing (20) and the current collector (40) to prevent contact between the battery housing (20) and the current collector (40) having opposite polarities.

[0060] The current collector (40) may be placed on one side of the electrode assembly (10). Referring to Fig. 2, the current collector (40) may include a first coupling portion (41), a second coupling portion (42), and a bridge portion (43).

[0061] 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 of the first uncoated portion (11) is maximized.

[0062] The second connecting portion (42) can be electrically connected to the first portion (31) of the battery terminal (30). The second connecting portion (42) can 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 a laser irradiated through the winding center hole (10a).

[0063] The above bridge portion (43) may be configured to electrically connect the first coupling portion (41) and the second coupling portion (42). A plurality of the first coupling portions (41) may be provided along the circumference of the battery cell (1). In this case, a plurality of the bridge portions (43) may also be provided.

[0064] Meanwhile, if an overcurrent exceeding the standard value occurs in the battery cell (1), the current collector (40) may induce a rupture of the bridge portion (43). In particular, the external short-circuit test is one of the important tests in the safety evaluation items. Accordingly, by inducing the current collector (40) to self-fuse in the event of an external short-circuit, the ignition of the battery cell (1) can be minimized.

[0065] To this end, the bridge portion (43) may be formed to have a smaller cross-sectional area than the first connecting portion (41). For example, the bridge portion (43) may be formed to have at least one of a width (W) or a thickness (h) smaller than the first connecting portion (41). That is, the volume of the bridge portion (43) may be formed to be smaller than the volume of the first connecting portion (41).

[0066] In addition, the bridge portion (43) of the current collector (40) included in the battery cell (1) according to one embodiment of the present invention may be configured to have a cross-sectional area of ​​50% or less of the bridge portion of the current collector included in a conventional battery cell.

[0067] Furthermore, according to the present invention, the cross-sectional area of ​​the bridge portion (43) may be configured to be 5% or less of the total cross-sectional area of ​​the current collector (40). Here, the total cross-sectional area of ​​the current collector (40) may mean the area inside the outermost edge 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).

[0068] In addition, the volume of the bridge portion (43) may be configured to be 5% or less of the total volume of the current collector (40). Here, the volume 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) * the thickness (h) of the current collector (40). For example, the thickness (h) of the current collector (40) may be configured to be 0.2 mm.

[0069] According to the above-described embodiment of the present invention, when a battery cell (1) malfunctions, the current collector (40) can be short-circuited without ignition by fusing itself. In addition, when an overcurrent occurs in the battery cell (1), the current collector (40) itself can be rapidly ruptured, thereby quickly blocking the overcurrent. As a result, the safety of the battery cell (1) can be ensured.

[0070]

[0071] As a more specific example, the cross-sectional area of ​​the bridge portion (43) may be configured to be 3% or more and 5% or less of the total cross-sectional area of ​​the current collector (40). In this case, the energy density of the battery cell (1) may be approximately 120 Wh or more.

[0072] Alternatively, the cross-sectional area of ​​the bridge portion (43) may be configured to be 2% or more and 4% or less of the total cross-sectional area of ​​the current collector (40). In this case, the energy density of the battery cell (1) may be approximately 99 Wh or more and 120 Wh or less.

[0073] In addition, it is preferable that the cross-sectional area of ​​the bridge portion (43) be at least 2% of the total 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.

[0074]

[0075] Meanwhile, referring to FIGS. 2 and 3, the current collector (40) may be provided with a fusing unit (F). The fusing unit (F) may be configured to be ruptured when an abnormality occurs in the battery cell (1). That is, when an overcurrent occurs in the battery cell (1), a rupture of the fusing unit (F) may be induced.

[0076] The fusing part (F) may be provided in the bridge part (43). According to the above-described embodiment of the present invention, the fusing part (F) that is ruptured when an overcurrent occurs in the battery cell (1) is provided at the connection part between the second connecting part (42) of the current collector (40) and the bridge part (43), thereby partially increasing the resistance in the path of the large current entering through the battery terminal (30) or leaving from the battery terminal (30), thereby more effectively inducing the rupture of the current collector (40).

[0077] In particular, the fusing part (F) may be provided at the connection portion of the bridge part (43) and the second coupling part (42). Furthermore, the fusing part (F) may be provided at a portion of the bridge part (43) closer to the second coupling part (42).

[0078] According to the above-described embodiment of the present invention, when an abnormal situation occurs in the battery cell (1), the part where the second connecting portion (42), which is the part where the heat is most concentrated in the current collector (40), and the bridge portion (43) are connected may be broken. As a result, the electrical connection of the battery cell (1) can be quickly cut off, thereby ensuring the safety of use of the battery cell (1).

[0079]

[0080] FIG. 4 is a drawing showing that a current collector (first current collector) included in a battery cell according to another embodiment of the present invention has two bridge parts, FIG. 5 is a drawing showing that a current collector (first current collector) included in a battery cell according to another embodiment of the present invention has three bridge parts, and FIG. 6 is a drawing showing that a current collector (first current collector) included in a battery cell according to another embodiment of the present invention has four bridge parts. In addition, FIG. 7 is a drawing showing whether fusing is performed according to the number and width of bridge parts in the current collectors (first current collectors) of FIGS. 4 to 6.

[0081] Referring to FIGS. 4 to 6, a plurality of bridge portions (43) may be provided. The bridge portions (43) may be arranged along the circumferential direction of the electrode assembly (10). In addition, the widths (W) of the plurality of bridge portions (43) may all be configured to be the same. Alternatively, at least some of the bridge portions (43) among the plurality of bridge portions (43) may be configured to have different widths (W).

[0082] When a plurality of bridge sections (43) are provided, the cross-sectional area of ​​the bridge sections (43) can be varied by various combinations of the number of bridge sections (43) and the width (W). However, the total cross-sectional area of ​​the plurality of bridge sections (43) can be configured to be 5% or less of the total cross-sectional area of ​​the current collector (40).

[0083] Referring to FIG. 7 together with FIG. 4 to FIG. 6, whether fusing is performed according to the number and width (W) of bridge parts (43) is explained.

[0084] The bridge portion (43) may be composed of two, as in the embodiment illustrated in FIG. 4. At this time, referring to FIG. 6, the width (W) of the bridge portion (43) may be configured to be approximately 1.5 mm. In addition, the width (W) of the bridge portion (43) may be configured to be approximately 3.0 mm. In addition, the width (W) of the bridge portion (43) may be configured to be approximately 4.5 mm. In addition, the width (W) of the bridge portion (43) may be configured to be approximately 6.0 mm.

[0085] The bridge portion (43) may be composed of three, as in the embodiment illustrated in Fig. 5. At this time, referring to Fig. 6, the width (W) of the bridge portion (43) may be composed of approximately 1.5 mm. In addition, the width (W) of the bridge portion (43) may be composed of approximately 3.0 mm.

[0086] The bridge portion (43) may be composed of four, as in the embodiment illustrated in Fig. 6. At this time, referring to Fig. 6, the width (W) of the bridge portion (43) may be composed of approximately 1.5 mm. In addition, the width (W) of the bridge portion (43) may be composed of approximately 3.0 mm.

[0087] That is, referring to Fig. 6, when the total cross-sectional area of ​​the plurality of bridge portions (43) is configured to be 5% or less of the total cross-sectional area of ​​the current collector (40), fusing of the current collector (40) can be induced. On the other hand, when the total cross-sectional area of ​​the plurality of bridge portions (43) is configured to exceed 5% of the total cross-sectional area of ​​the current collector (40), it can be confirmed that fusing does not occur smoothly and ignition occurs.

[0088]

[0089] Meanwhile, the cross-sectional area of ​​the fusing portion (F) (the portion indicated as A in FIG. 3) can be defined as the width (W) of the bridge portion (43) * the thickness (h) of the current collector (40). The fusing portion (F) can be provided for each bridge portion (43). At this time, referring to FIG. 7, regardless of the combination of the number and width (W) of the bridge portions (43), the total sum of the cross-sectional areas of the fusing portions (F) is 2.4 mm. 2 In the following cases, it can be confirmed that fusing is occurring smoothly.

[0090] In particular, the cross-sectional area of ​​the fusing section (F) is 1.8 mm 2 It can be composed as follows. Moreover, the cross-sectional area of ​​the fusing part (F) is 1.2 mm. 2 It can be composed as follows. In addition, the cross-sectional area of ​​the fusing part (F) is 0.9 mm. 2 It can be composed as follows. In addition, the cross-sectional area of ​​the fusing part (F) is 0.6 mm. 2 It can be composed of the following:

[0091]

[0092] Meanwhile, when an abnormality occurs in the battery cell (1), the fusing time of the current collector (40) may be within about 20 seconds. Preferably, the fusing time of the current collector (40) may be within about 15 seconds. Referring to Fig. 7, when the total cross-sectional area of ​​the plurality of bridge portions (43) is configured to be 5% or less of the total cross-sectional area of ​​the current collector (40), it can be confirmed that fusing is performed within about 20 seconds and thus no ignition occurs.

[0093]

[0094] FIG. 8 is a drawing showing a current collector (first current collector) included in a battery cell according to another embodiment of the present invention, and FIG. 9 is a CT image showing a state in which a bridge portion is fused when an overcurrent occurs in the current collector (first current collector) included in a battery cell according to another embodiment of the present invention. In addition, FIG. 10 is a drawing showing whether fusing occurs according to the width of the bridge portion in the current collector (first current collector) of FIG. 8.

[0095] Fig. 11 is experimental data showing the results of an external short circuit when the width of the bridge portion in the collector (first collector) of Fig. 8 is 2.5 mm.

[0096] Meanwhile, referring to FIGS. 2 and 8, the current collector (40) may have a rim portion (44) positioned on the outer periphery 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).

[0097] As in the above-described embodiment of the present invention, when the first coupling portion (41) and the second coupling portion (42) are not directly connected to each other but are indirectly connected via the rim portion (44), the impact applied to the battery cell (1) can be dispersed. That is, the impact applied to the weld portion of the first coupling portion (41) can be minimized from being transferred to the weld portion of the second coupling portion (42), and the impact applied to the weld portion of the second coupling portion (42) can also be minimized from being transferred to the first coupling portion (41).

[0098] In addition, the current collector (40) may be positioned so that the first coupling portion (41) and the second coupling portion (42) described above are spaced apart from each other along the radial direction of the electrode assembly (10). That is, an empty space may be formed between the first coupling portion (41) and the second coupling portion (42) along the radial direction.

[0099] In particular, as in the embodiment illustrated in FIG. 8, the current collector (40) may have a slit line (45). The slit line (45) may be formed by penetrating the current collector (40). That is, the slit line (45) may be formed by penetrating the current collector (40) in a roughly circular plate shape having a roughly flat shape. A first coupling portion (41), a second coupling portion (42), and a 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).

[0100] In this case, when a structure in which each component of the current collector (40) is distinguished by a slit line (45) is applied, a complex process for forming each component, 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 relatively easily by simply forming a cut line on a metal plate. As a result, the manufacturing process of the current collector (40) can be simplified, and thus productivity and processability can be improved when manufacturing a battery cell (1).

[0101] Likewise, in the embodiment illustrated in Fig. 8, the cross-sectional area of ​​the bridge portion (43) may be configured to be 5% or less of the total cross-sectional area of ​​the current collector (40).

[0102] More specifically, the width (W) of the bridge portion (43) can be configured to be about 3.0 mm. In this case, the total cross-sectional area of ​​the fusing portion (F) is 2.4 mm. 2 It may be as follows. As shown in the experimental results of Fig. 10, when the width (W) of the bridge portion (43) is configured to be approximately 3.0 mm, it can be confirmed that fusing is performed smoothly within 20 seconds during an external short-circuit test of the battery cell (1).

[0103] For example, the width (W) of the bridge portion (43) can be configured to be approximately 2.75 mm. In this case, the total cross-sectional area of ​​the fusing portion (F) is 2.2 mm. 2 It could be as follows:

[0104] Preferably, the width (W) of the bridge portion (43) can be configured to be about 2.5 mm. In this case, the total cross-sectional area of ​​the fusing portion (F) is 2.0 mm. 2 It could be as follows:

[0105] As shown in the experimental results of FIGS. 10 and 11, when the width (W) of the bridge portion (43) is configured to be approximately 2.5 mm, it can be confirmed that fusing is performed smoothly during an external short-circuit test of the battery cell (1). In addition, in this case, the fusing time of the bridge portion (43) can be approximately 13.5 seconds, or less than approximately 20 seconds.

[0106] Accordingly, referring to FIGS. 10 and 11, it can be confirmed that in a case where the total cross-sectional area of ​​a plurality of bridge portions (43) in a current collector (40) equipped with a slit line (45) is configured to be 5% or less of the total cross-sectional area of ​​the current collector (40), fusing occurs within about 20 seconds and ignition does not occur.

[0107]

[0108] FIG. 12 is a diagram showing whether fusing occurs depending on the crystal structure of the first electrode of the current collector (first current collector) included in the battery cell according to one embodiment of the present invention. In addition, FIG. 13 is experimental data showing the results of an external short circuit when the crystal structure of the first electrode in the current collector (first current collector) according to one embodiment of the present invention is SC:PC = 5:5.

[0109] As an example, the crystal structure of the first electrode may be composed of 100% single crystal particles (SC). Referring to Fig. 12, when the crystal structure of the first electrode is 100% SC, it can be confirmed that fusing occurred in all cases within 15 seconds and no ignition occurred.

[0110] In another embodiment, the crystal structure of the first electrode may be composed of a mixture of single particles (SC) and multi-particles (PC, Poly Crystal). For example, the crystal structure of the first electrode may be composed of single particles (SC): multi-particles (PC) = 5:5. In this case, referring to Fig. 12, it can be confirmed that fusing occurred in all cases within 15 seconds and that no ignition occurred.

[0111] Meanwhile, in the experiments of FIGS. 12 and 13, the experiment was performed with a current collector (40) having a width (W) of the bridge portion (43) of 2.5 mm. That is, as in the embodiment of the present invention, when the cross-sectional area of ​​the bridge portion (43) is 5% or less of the total cross-sectional area of ​​the current collector (40), even when the crystal structure of the first electrode is a mixture of single particles and multiple particles, fusing may occur and ignition may not occur, just as in the case where it is composed of only single particles.

[0112]

[0113] FIG. 14 is a drawing showing the structure of a lower portion of a battery cell according to one embodiment of the present invention.

[0114] Referring to FIG. 14, a battery cell (1) according to an embodiment of the present invention may include a current collector (second current collector) (50). The current collector (50) may be configured to electrically connect an electrode assembly (10) and a battery housing (20). The current collector (50) may be electrically connected to a second electrode of the electrode assembly (10). The current collector (50) may be electrically coupled to a second non-conductive portion (12) provided on a second surface of the electrode assembly (10). The current collector (50) may be electrically coupled to an inner surface of the battery housing (20). The current collector (50) may be electrically coupled to a beading portion (21) formed by press-fitting an outer peripheral surface of the battery housing (20).

[0115] The battery cell (1) may include a cap (60). The cap (60) may be configured to close an opening of the battery housing (20). The cap (60) may be secured by a crimping portion (22) configured to extend and bend from a beading portion (21) of the battery housing (20) and wrap around an edge of the cap (60). A sealing member (second sealing member) (G2) may be interposed between the cap (60) and an inner surface of the battery housing (20). The cap (60) may include a venting portion (61) configured to be weaker compared to the remaining area. The venting portion (61) may be configured to partially reduce the thickness of the cap (60). The venting portion (61) may be configured to be ruptured when the internal pressure of the battery cell (1) increases to a predetermined pressure or higher.

[0116]

[0117] FIG. 15 is a drawing showing a battery pack including a battery cell according to one embodiment of the present invention.

[0118] Referring to FIG. 15, a battery pack (3) according to an embodiment of the present invention may include a battery cell (1) according to an embodiment of the present invention and a pack housing (2) accommodating 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 invention may be configured such that the battery terminal (30) and the closing portion of the battery housing (20) may function as a first electrode terminal and a second electrode terminal, respectively. Therefore, when arranging a plurality of battery cells (1) within the pack housing (2), electrical connection can be made at the upper portion of the battery cells (1) by arranging the terminals (30) of all battery cells (1) so that they face upward.

[0119]

[0120] Fig. 16 is a drawing showing a vehicle according to one embodiment of the present invention.

[0121] Referring to FIG. 16, a vehicle (5) according to one embodiment of the present invention may include a battery pack (3) according to one embodiment of the present invention. The vehicle (5) may be configured to operate by receiving power from the battery pack (3). The vehicle (5) may be, for example, an electric vehicle or a hybrid vehicle.

[0122]

[0123] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. Electrode assembly; A battery housing having an opening on one side and accommodating the electrode assembly through the opening; A battery terminal configured to be electrically connected to the electrode assembly through a closing portion provided on the opposite side of the opening portion of the battery housing; and A current collector comprising a first coupling portion configured to be electrically coupled with the electrode assembly, a second coupling portion configured to be electrically coupled with the battery terminal, and a bridge portion configured to electrically connect between the first coupling portion and the second coupling portion, A battery cell characterized in that the cross-sectional area of ​​the bridge portion is configured to be 5% or less of the entire cross-sectional area of ​​the entire collector.

2. In paragraph 1, A battery cell characterized in that the cross-sectional area of ​​the bridge portion is comprised of 3% or more and 5% or less of the entire cross-sectional area of ​​the entire collector.

3. In paragraph 1, A battery cell characterized in that the cross-sectional area of ​​the bridge portion is comprised of 2% or more and 4% or less of the entire cross-sectional area of ​​the entire collector.

4. In paragraph 1, The above entire house A battery cell characterized by having a fusing part provided in the above bridge part and configured to be ruptured when an abnormality occurs in the battery cell.

5. In paragraph 1, The above bridge section is provided in multiple numbers, A battery cell characterized in that the total cross-sectional area of ​​the plurality of bridge portions is 5% or less of the total cross-sectional area of ​​the entire collector.

6. In paragraph 1, A battery cell characterized in that, when the above battery cell abnormality occurs, the fusing time of the entire collector is within about 20 seconds.

7. In paragraph 1, The above-mentioned collector has a rim portion positioned on the outer periphery of the first coupling portion and the second coupling portion, A battery cell characterized in that the bridge portion is configured to connect the rim portion and the second connecting portion.

8. In paragraph 1, A battery cell, characterized in that the first coupling portion and the second coupling portion are positioned spaced apart from each other along the radial direction of the electrode assembly.

9. In paragraph 8, The above entire house A battery cell characterized by having a slit line configured to mutually space the first coupling portion and the second coupling portion.

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

11. A vehicle characterized by including a battery cell according to any one of claims 1 to 9.

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