Battery cells, battery packs, and automobiles containing them

Abstract

A battery cell according to one embodiment of the present invention includes an electrode assembly, a battery housing having an opening on one side and housing the electrode assembly through the opening, a battery terminal configured to be electrically connected to the electrode assembly via a closing portion provided on the opposite side of the opening of the battery housing, and a current collector having 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 may be configured to be 5% or less of the total cross-sectional area of ​​the current collector.

Description

Technical Field

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

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

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

Background Art

[0004] Secondary batteries with high ease of application according to product groups and having electrical characteristics such as high energy density are widely applied not only to portable devices but also to electric vehicles (EVs) and hybrid electric vehicles (HEVs) driven by electric drive sources. In addition to the primary advantage of significantly reducing the use of fossil fuels, such secondary batteries are attracting attention as a new energy source for environmental consideration and energy efficiency improvement in that no by-products are generated during energy use.

[0005] Currently widely used types of rechargeable batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of such a single rechargeable battery cell is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, multiple battery cells may be connected in series to form a battery pack. Alternatively, depending on the required charge and discharge capacity of the battery pack, multiple battery cells may be connected in parallel to form a battery pack. Thus, 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 and discharge capacity.

[0006] On the other hand, current fuse devices used in battery cells include positive temperature coefficient thermistors (PTC thermistors) and thermal cut-outs (TCOs). However, PTC thermistors and TCOs have the drawback that their own resistance increases with repeated operation, raising the overall resistance of the circuit.

[0007] Furthermore, all of the above elements operate in response to heat generated by overcurrent. In other words, these elements are designed to interrupt the flow of current only when an overcurrent occurs in the circuit current path due to overcharging or other reasons, and the temperature rises as a result.

[0008] Therefore, in the case of the above-mentioned element, it can only operate and interrupt the overcurrent after the overheating has already created a situation where safety may be threatened. It cannot interrupt the current immediately after the cause of the temperature rise occurs. Thus, even if the internal pressure increases due to an abnormal temperature rise inside the battery cell, if the overcurrent is not interrupted at the appropriate time, safety problems such as fire or explosion may occur.

[0009] Furthermore, since all of the above elements operate simply in response to temperature, they have limitations in their application to battery cells that require high output, such as those used in automotive battery packs. Specifically, automotive battery packs require high C-rates, which tend to generate a large amount of heat. However, elements such as positive temperature coefficient thermistors (PTC thermistors), thermal cut-outs (TCOs), and thermal fuses have the problem of potentially activating excessively prematurely when exposed to such high-temperature environments.

[0010] Therefore, there is a need for a battery cell that can be used even in environments where high current flows, and that has a structure that can interrupt the current in advance when an event that could cause a temperature rise (for example, an increase in the internal pressure of the battery cell) occurs, before the temperature rises to a level where safety problems may arise. [Overview of the project] [Problems that the invention aims to solve]

[0011] This invention has been made in view of the above problems, and aims to enable rapid disconnection of electrical connections when an overcurrent exceeding a standard value occurs in a battery cell.

[0012] However, the technical problems that the present invention aims to solve are not limited to those described above, and other problems not explicitly mentioned can be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0013] A battery cell according to one embodiment of the present invention for solving the above-mentioned problems includes an electrode assembly, a battery housing having an opening on one side and housing the electrode assembly through the opening, a battery terminal configured to be electrically connected to the electrode assembly via a closing portion provided on the opposite side of the opening of the battery housing, and a current collector having 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 may be configured to be 5% or less of the total cross-sectional area of ​​the current collector.

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

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

[0016] Multiple bridge sections are provided, and the total cross-sectional area of ​​the multiple bridge sections may be configured to be 5% or less of the total cross-sectional area of ​​the current collector.

[0017] When an abnormality occurs in the battery cell, the fusing time of the current collector can be set to within approximately 20 seconds.

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

[0019] The current collector may include a rim portion located on the outer circumference 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.

[0020] The first and second coupling portions may be arranged spaced apart from each other along the radial direction of the electrode assembly.

[0021] The current collector may include a slit line configured to separate the first coupling portion and the second coupling portion from each other.

[0022] The battery pack according to the present invention may include the battery cell according to the present invention.

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

Advantages of the Invention

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

[0025] In addition to this, the present invention can have various other effects, and for these, explanations will be provided in the column of each implementation configuration, or for effects that can be easily inferred by those skilled in the art, the explanations thereof will be omitted.

[0026] The drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention to be described later. Therefore, the present invention is not to be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0027] [Figure 1] It is a diagram showing the upper portion structure of a battery cell according to an embodiment of the present invention. [Figure 2] It is a perspective view of a current collector (first current collector) included in a battery cell according to an embodiment of the present invention. [Figure 3] It is a cross-sectional view taken along the line I-I' of FIG. 2, and shows 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 invention. [Figure 4]This figure shows a configuration in which two bridge sections are provided in a current collector (first current collector) included in a battery cell according to another embodiment of the present invention. [Figure 5] This figure shows a configuration in which three bridge sections are provided in a current collector (first current collector) included in a battery cell according to yet another embodiment of the present invention. [Figure 6] This figure shows a configuration in which four bridge sections are provided in a current collector (first current collector) included in a battery cell according to yet another embodiment of the present invention. [Figure 7] Figures 4 to 6 show the current collector (first current collector) and indicate whether or not there is fusing depending on the number and width of the bridge section. [Figure 8] This figure shows a current collector (first current collector) included in a battery cell according to yet another embodiment of the present invention. [Figure 9] This is a CT image showing a state in which the bridge portion of a current collector (first current collector) included in a battery cell according to yet another embodiment of the present invention has fused when an overcurrent occurs. [Figure 10] Figure 8 shows the presence or absence of fusing in the current collector (first current collector) according to the width of the bridge section. [Figure 11] This is experimental data showing the results of an external short-circuit test when the bridge section of the current collector (first current collector) shown in Figure 8 has a width of 2.5 mm. [Figure 12] This figure shows the presence or absence of fusing in a current collector (first current collector) included in a battery cell according to one embodiment of the present invention, depending on the crystal structure of the first electrode. [Figure 13] This is experimental data showing the results of an external short-circuit test in a current collector (first current collector) according to one embodiment of the present invention, where the crystal structure of the first electrode is SC:PC = 5:5. [Figure 14] This figure shows the lower portion structure of a battery cell according to one embodiment of the present invention. [Figure 15]This figure shows a battery pack containing a battery cell according to one embodiment of the present invention. [Figure 16] This is a diagram showing an automobile relating to one embodiment of the present invention. [Modes for carrying out the invention]

[0028] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Prior to this, terms and words used in this specification and in the claims shall not be interpreted in a manner limited to their general or dictionary meanings, but in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention, and shall be interpreted in a manner consistent with the technical spirit of the present invention.

[0029] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the present invention. It should be understood that there are various equivalent and modified embodiments that can be substituted for these at the time of filing this application.

[0030] Furthermore, the present invention includes various embodiments. For each embodiment, redundant explanations of substantially identical or similar configurations will be omitted, and the explanation will focus on the differences.

[0031] First, with reference to Figures 1 to 3, a battery cell 1 according to one embodiment of the present invention will be described.

[0032] Figure 1 shows the upper portion structure of a battery cell according to one embodiment of the present invention, and Figure 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. Figure 3 shows a cross-section of line I-I' in Figure 2, and is a diagram showing the state in which the bridge portion is fused when an overcurrent occurs in the current collector (first current collector) included in a battery cell according to one embodiment of the present invention.

[0033] Referring to Figures 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, battery terminals 30, and a current collector (first current collector) 40. The battery cell 1 may be a rechargeable secondary battery. The battery cell 1 may be a cylindrical battery.

[0034] 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 structure 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 structure, a winding center hole 10a may be formed in the central region of the winding.

[0035] The first electrode may include a first blank portion 11, which is a region where the electrode active material is not coated. The first blank portion 11 may extend from one end of the first electrode along the winding direction of the electrode assembly 10. As a result, the first blank portion 11 may be provided on a first surface substantially perpendicular to the outer circumferential surface of the electrode assembly 10.

[0036] The second electrode may include a second blank portion 12, which is a region not coated with electrode active material (see Figure 14). The second blank portion 12 may extend from one end of the second electrode along the winding direction of the electrode assembly 10. As a result, the second blank portion 12 may be provided on a second surface (a surface located opposite to the first surface) substantially perpendicular to the outer circumferential surface of the electrode assembly 10.

[0037] Although not specifically shown in the drawings, the first blank section 11 and / or the second blank section 12 may include a plurality of segments formed along the winding direction of the electrode assembly 10. These segments may be formed by notching the first blank section 11 and / or the second blank section 12 to a predetermined depth. The plurality of segments may be bent along the substantially radial direction of the electrode assembly 10. In this case, parts of the segments adjacent to each other along the radial direction may overlap.

[0038] The battery housing 20 may be configured to accommodate the electrode assembly 10 through an opening formed on one side. The battery housing 20 may have a closure formed on the opposite side of the opening. The battery housing 20 may contain a conductive metal. The battery housing 20 may also be electrically connected to the second electrode of the electrode assembly 10.

[0039] The battery terminal 30 may be configured to be electrically connected to the electrode assembly 10 via a closing portion provided on the opposite side of the opening of the battery housing 20. The battery terminal 30 may be electrically connected, for example, to the first electrode of the electrode assembly 10. In this case, the battery terminal 30 may function as the first terminal of the battery cell 1. The battery terminal 30 and the battery housing 20 may have opposite polarities, in which case a first sealing member G1 may be interposed between the battery housing 20 and the battery terminal 30 to prevent contact between the two members and to ensure the airtightness of the battery housing 20.

[0040] 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 inside the battery housing 20. The first portion 31 may be located in 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 in the center of the closure of the battery housing 20.

[0041] The battery terminal 30 may include a third portion 33 provided on the outside of the first portion 31. The third portion 33 may be reveting toward the closing portion of the battery housing 20 to secure the battery terminal 30 to the battery housing 20.

[0042] 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.

[0043] To prevent contact between the battery housing 20 and the current collector 40, which have opposite polarities, an insulator IS may be interposed between the current collector 40 and the inner surface of the closing portion of the battery housing 20.

[0044] The current collector 40 may be positioned on one side of the electrode assembly 10. Referring to Figure 2, the current collector 40 may include a first coupling portion 41, a second coupling portion 42, and a bridge portion 43.

[0045] 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 blank portion 11 of the electrode assembly 10. The first coupling portion 41 may be coupled to a coupling surface formed by bending the first blank portion 11. At least a portion of the first coupling portion 41 may be coupled to the first blank portion 11 in the region where the number of overlapping layers of the divided pieces of the first blank portion 11 is maximized.

[0046] 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 winding center hole 10a of the electrode assembly 10, or by a laser irradiated through the winding center hole 10a.

[0047] The bridge portion 43 may be configured to electrically connect the first coupling portion 41 and the second coupling portion 42. Multiple first coupling portions 41 may be provided along the circumferential direction of the battery cell 1. In this case, multiple bridge portions 43 may also be provided.

[0048] On the other hand, in the current collector 40, if an overcurrent exceeding a standard value occurs in the battery cell 1, a break in the bridge section 43 may be induced. In particular, the external short-circuit test is one of the important tests among the safety evaluation items. Therefore, by inducing the current collector 40 to fuse on its own during the external short-circuit test, the ignition of the battery cell 1 can be minimized.

[0049] For this reason, the bridge portion 43 may be formed with a smaller cross-sectional area than the first joint portion 41. For example, the bridge portion 43 may be formed with a width W or thickness h smaller than that of the first joint portion 41. That is, the volume of the bridge portion 43 may be smaller than the volume of the first joint portion 41.

[0050] Furthermore, 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 that of the bridge portion of a conventional battery cell.

[0051] Furthermore, according to the present invention, the cross-sectional area of ​​the bridge portion 43 can 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. Also, the cross-sectional area of ​​the bridge portion 43 may be defined by the length d × width W of the bridge portion 43.

[0052] Furthermore, the volume of the bridge section 43 may be configured to be 5% or less of the total volume of the current collector 40. Here, the volume of the bridge section 43 may be defined by the length d of the bridge section 43 × the width W of the bridge section 43 × the thickness h of the current collector 40. For example, the thickness h of the current collector 40 may be 0.2 mm.

[0053] According to the above-described embodiment of the present invention, when an abnormality occurs in the battery cell 1, the current collector 40 fuses on its own, thereby forming a short circuit without ignition. Furthermore, when an overcurrent occurs in the battery cell 1, a rapid disconnection of the current collector 40 itself is induced, allowing for rapid interruption of the overcurrent. This ensures the safety of the battery cell 1.

[0054] As a more specific example, the cross-sectional area of ​​the bridge section 43 may be configured to be between 3% and 5% of the total cross-sectional area of ​​the current collector 40. In such a case, the energy density of the battery cell 1 can be approximately 120 Wh or more.

[0055] Alternatively, the cross-sectional area of ​​the bridge section 43 may be configured to be between 2% and 4% of the total cross-sectional area of ​​the current collector 40. In this case, the energy density of the battery cell 1 may be between approximately 99Wh and 120Wh.

[0056] Furthermore, it is preferable that the cross-sectional area of ​​the bridge portion 43 be 2% or more of the total cross-sectional area of ​​the current collector 40. This is because resistance can increase as the cross-sectional area of ​​the bridge portion 43 decreases, and this is done to minimize that increase.

[0057] On the other hand, referring to Figures 2 and 3, the current collector 40 may include a fusing section F. The fusing section F may be configured to rupture when an abnormality occurs in the battery cell 1. That is, rupture of the fusing section F may be induced when an overcurrent occurs in the battery cell 1.

[0058] The fusing section F may be provided in the bridge section 43. According to the above embodiment of the present invention, the fusing section F, which breaks when an overcurrent occurs in the battery cell 1, is provided at the connection point between the second coupling section 42 of the current collector 40 and the bridge section 43. This makes it possible to locally increase the resistance in the path of the large current flowing in or out from the battery terminals 30, thereby more effectively inducing the breakage of the current collector 40.

[0059] In particular, the fusing section F may be provided at the connection point between the bridge section 43 and the second coupling section 42. Furthermore, the fusing section F may be provided in the bridge section 43 at a position closer to the second coupling section 42.

[0060] According to the above-described embodiment of the present invention, when an abnormality occurs in the battery cell 1, the connection between the second coupling portion 42 and the bridge portion 43, which is the part of the current collector 40 where heat is most concentrated, can be broken. As a result, the electrical connection of the battery cell 1 is quickly interrupted, and safety in the use of the battery cell 1 can be ensured.

[0061] Figure 4 shows a configuration in which two bridge sections are provided in a current collector (first current collector) included in a battery cell according to another embodiment of the present invention, Figure 5 shows a configuration in which three bridge sections are provided in a current collector (first current collector) included in a battery cell according to yet another embodiment of the present invention, and Figure 6 shows a configuration in which four bridge sections are provided in a current collector (first current collector) included in a battery cell according to yet another embodiment of the present invention. Figure 7 shows the presence or absence of fusing according to the number and width of bridge sections in the current collector (first current collector) in Figures 4 to 6.

[0062] Referring to Figures 4 to 6, multiple bridge sections 43 may be provided. The bridge sections 43 may be arranged along the circumferential direction of the electrode assembly 10. Furthermore, the width W of all multiple bridge sections 43 may be the same. Alternatively, at least some of the multiple bridge sections 43 may be configured to have different widths W.

[0063] When multiple bridge sections 43 are provided, the cross-sectional area of ​​the bridge sections 43 can vary in various ways depending on the number of bridge sections 43 and the width W of each bridge section 43. However, the total cross-sectional area of ​​the multiple bridge sections 43 can be configured to be 5% or less of the total cross-sectional area of ​​the current collector 40.

[0064] Referring to Figures 4 through 6 and Figure 7, the presence or absence of fusing according to the number and width W of the bridge sections 43 will be explained.

[0065] The bridge section 43 may consist of two parts, as shown in the embodiment in Figure 4. Referring to Figure 7, the width W of the bridge section 43 may be approximately 1.5 mm. Alternatively, the width W of the bridge section 43 may be approximately 3.0 mm. Furthermore, the width W of the bridge section 43 may be approximately 4.5 mm. Also, the width W of the bridge section 43 may be approximately 6.0 mm.

[0066] The bridge section 43 may consist of three parts, as shown in the embodiment in Figure 5. Referring to Figure 7, the width W of the bridge section 43 may be approximately 1.5 mm. Alternatively, the width W of the bridge section 43 may be approximately 3.0 mm.

[0067] The bridge section 43 may consist of four parts, as shown in the embodiment in Figure 6. Referring to Figure 7, the width W of the bridge section 43 may be approximately 1.5 mm. Alternatively, the width W of the bridge section 43 may be approximately 3.0 mm.

[0068] Specifically, referring to Figure 7, if the total cross-sectional area of ​​the multiple bridge sections 43 is 5% or less of the total cross-sectional area of ​​the current collector 40, fusing of the current collector 40 may be induced. On the other hand, if the total cross-sectional area of ​​the multiple bridge sections 43 is greater than 5% of the total cross-sectional area of ​​the current collector 40, fusing does not occur smoothly, and ignition has been confirmed to occur.

[0069] On the other hand, the cross-sectional area of ​​the fusing section F (the part indicated by A in Figure 3) can be defined as the width W of the bridge section 43 × the thickness h of the current collector 40. A fusing section F may be provided in each bridge section 43. In this case, referring to Figure 7, regardless of the combination of the number of bridge sections 43 and their widths W, the total cross-sectional area of ​​the fusing sections F is 2.4 mm². 2 It has been confirmed that fusing proceeds smoothly under the following conditions:

[0070] In particular, the cross-sectional area of ​​the fusing section F is 1.8 mm². 2 It can be configured as follows. Furthermore, the cross-sectional area of ​​the fusing section F is 1.2 mm². 2 It can be configured as follows. The cross-sectional area of ​​the fusing section F is 0.9 mm². 2 It can be configured as follows. The cross-sectional area of ​​the fusing section F is 0.6 mm². 2 It can be structured as follows:

[0071] On the other hand, if an abnormality occurs in the battery cell 1, the fusing time of the current collector 40 may be within approximately 20 seconds. Preferably, the fusing time of the current collector 40 may be within approximately 15 seconds. Referring to Figure 7, it has been confirmed that when the total cross-sectional area of ​​the multiple bridge sections 43 is configured to be 5% or less of the total cross-sectional area of ​​the current collector 40, fusing occurs within approximately 20 seconds and no fire occurs.

[0072] Figure 8 shows a current collector (first current collector) included in a battery cell according to yet another embodiment of the present invention, and Figure 9 is a CT image showing the state in which the bridge portion is fused when an overcurrent occurs in the current collector (first current collector) included in a battery cell according to yet another embodiment of the present invention. Figure 10 is a diagram showing the presence or absence of fusing according to the width of the bridge portion in the current collector (first current collector) of Figure 8.

[0073] Figure 11 shows experimental data illustrating the results of an external short-circuit test when the bridge section of the current collector (first current collector) in Figure 8 has a width of 2.5 mm.

[0074] On the other hand, referring to Figures 2 and 8, the current collector 40 may include a rim portion 44 located 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.

[0075] 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 but are indirectly connected via the rim portion 44, the impact applied to the battery cell 1 can be dispersed. That is, the transmission of the impact applied to the weld portion of the first coupling portion 41 to the weld portion of the second coupling portion 42 can be minimized, and the transmission of the impact applied to the weld portion of the second coupling portion 42 to the first coupling portion 41 can also be minimized.

[0076] Furthermore, in the current collector 40, the first coupling portion 41 and the second coupling portion 42 described above may be positioned apart from each other along the radial direction of the electrode assembly 10. That is, a gap may be formed between the first coupling portion 41 and the second coupling portion 42 along the radial direction.

[0077] In particular, as shown in the embodiment in Figure 8, the current collector 40 may be provided with a slit line 45. The slit line 45 may be formed through the current collector 40. That is, the slit line 45 may be formed through the current collector 40, which is a substantially circular plate-shaped current collector with a substantially flat form. The first coupling portion 41, the second coupling portion 42, and the bridge portion 43 of the current collector 40 may be formed by such a slit line 45. In this case, the first coupling portion 41 and the second coupling portion 42 may be separated from each other radially by the slit line 45. Also, the first coupling portion 41 and the bridge portion 43 may be separated from each other circumferentially by the slit line 45.

[0078] Thus, when a structure is applied in which each component of the current collector 40 is separated by the slit line 45, the complex process for forming each component, namely the first coupling portion 41, the second coupling portion 42, and the bridge portion 43, becomes unnecessary, and the current collector 40 can be manufactured relatively easily by simply forming cut lines on a metal plate. This simplifies the manufacturing process of the current collector 40, potentially improving productivity and process efficiency during the manufacturing of the battery cell 1.

[0079] 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 total cross-sectional area of ​​the current collector 40.

[0080] More specifically, the width W of the bridge section 43 may be configured to be approximately 3.0 mm. In this case, the sum of the cross-sectional areas of the fusing sections F is 2.4 mm. 2 The following is possible. As is clear from the experimental results in Figure 10, when the width W of the bridge section 43 is approximately 3.0 mm, it has been confirmed that the battery cell 1 fuses smoothly within 20 seconds during an external short-circuit test.

[0081] For example, the width W of the bridge section 43 may be configured to be approximately 2.75 mm. In this case, the sum of the cross-sectional areas of the fusing sections F is 2.2 mm. 2 The following are possible:

[0082] Preferably, the width W of the bridge portion 43 can be configured to be approximately 2.5 mm. In this case, the sum of the cross-sectional areas of the fusing portions F is 2.0 mm. 2 The following are possible:

[0083] As is clear from the experimental results in Figures 10 and 11, it has been confirmed that when the width W of the bridge section 43 is approximately 2.5 mm, the battery cell 1 fuses smoothly during an external short-circuit test. In this case, the fusion time of the bridge section 43 is approximately 13.5 seconds, which can be said to be within approximately 20 seconds.

[0084] Therefore, referring to Figures 10 and 11, it has been confirmed that even in a current collector 40 provided with a slit line 45, if the total cross-sectional area of ​​the multiple bridge sections 43 is configured to be 5% or less of the total cross-sectional area of ​​the current collector 40, fusing occurs within approximately 20 seconds and no fire occurs.

[0085] Figure 12 shows the presence or absence of fusing due to the crystal structure of the first electrode in a current collector (first current collector) included in a battery cell according to one embodiment of the present invention. Figure 13 shows experimental data of the results of an external short circuit test when the crystal structure of the first electrode of the current collector (first current collector) according to one embodiment of the present invention is SC:PC=5:5.

[0086] For example, the crystal structure of the first electrode can consist of 100% single crystal (SC). Referring to Figure 12, it has been confirmed that in all cases where the crystal structure of the first electrode is 100% SC, fusing occurs within 15 seconds and ignition does not occur.

[0087] In another embodiment, the crystal structure of the first electrode may be composed of a mixture of single crystal (SC) and polycrystalline (PC). For example, the crystal structure of the first electrode may be composed of single crystal (SC):polycrystalline (PC) = 5:5. In this case as well, referring to Figure 12, it has been confirmed that fusing occurs within 15 seconds in all cases and that ignition does not occur.

[0088] On the other hand, the experiments in Figures 12 and 13 were conducted using a current collector 40 in which the width W of the bridge portion 43 is 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, it has been confirmed that fusing does not occur and ignition does not occur, even if the crystal structure of the first electrode is a mixed configuration of single crystal and polycrystal, just as in the case where it is composed only of single crystal.

[0089] Figure 14 shows the lower portion structure of a battery cell according to one embodiment of the present invention.

[0090] Referring to Figure 14, a battery cell 1 according to one embodiment of the present invention 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 blank 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 beading portion 21 formed by press-fitting onto the outer circumferential surface of the battery housing 20.

[0091] The battery cell 1 may include a cap 60. The cap 60 may be configured to seal the opening of the battery housing 20. The cap 60 may be secured by a crimping portion 22 that extends from the beading portion 21 of the battery housing 20, is bent, and surrounds the outer edge of the cap 60.

[0092] A sealing member (second sealing member) G2 may be interposed between the cap 60 and the inner surface of the battery housing 20. The cap 60 may include a vent portion 61 which is weaker than other areas. The vent portion 61 may be constructed 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 rises and exceeds a predetermined pressure.

[0093] Figure 15 shows a battery pack including a battery cell according to one embodiment of the present invention.

[0094] Referring to Figure 15, a battery pack 3 according to one embodiment of the present invention may include a battery cell 1 according to one embodiment of the present invention and a pack housing 2 that houses the battery cell 1. Multiple battery cells 1 may be provided, and these multiple battery cells 1 may be electrically connected to each other. In the battery cell 1 of the present invention, the battery terminals 30 and the closing portion of the battery housing 20 may be configured to function as a first electrode terminal and a second electrode terminal, respectively. Therefore, when arranging multiple battery cells 1 in the pack housing 2, by arranging the terminals 30 of all battery cells 1 facing upward, electrical connection on the upper side of the battery cells 1 becomes possible.

[0095] Figure 16 shows an automobile according to one embodiment of the present invention.

[0096] Referring to Figure 16, an automobile 5 according to one embodiment of the present invention may include a battery pack 3 according to one embodiment of the present invention. The automobile 5 may be configured to operate by being powered by the battery pack 3. The automobile 5 may be, for example, an electric vehicle or a hybrid vehicle.

[0097] Although the present invention has been described above based on limited embodiments and drawings, the present invention is not limited thereto, and it goes without saying that various modifications and variations are possible within the equivalent scope of the technical idea of ​​the present invention and the appended claims by persons with ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0098] 1 battery cell 2-pack housing 3 Battery Packs 5. Automobile 10 Electrode assembly 10a Winding center hole 11. First blank section 12. Second blank section 20 Battery Housing 21 Beading section 22 Crimping section 30 Battery terminals 31 Part 1 32 Part 2 33 Part 3 40 Current collector (1st current collector) 41 1st joint 42 Second joint 43 Bridge section 44 Rim section 45 Slit Line 50 Current collector (second current collector) 60 caps 61 Vent section G1 First sealing member G2 Second sealing member

Claims

1. Electrode assembly and A battery housing having an opening on one side and housing the electrode assembly through the opening, A battery terminal is configured to be electrically connected to the electrode assembly via a closing portion provided on the opposite side of the opening of the battery housing, 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, Includes, A battery cell in which the cross-sectional area of ​​the bridge portion is configured to be 5% or less of the total cross-sectional area of ​​the current collector.

2. The battery cell according to claim 1, wherein the cross-sectional area of ​​the bridge portion is configured to be 3% or more and 5% or less of the total cross-sectional area of ​​the current collector.

3. The battery cell according to claim 1, wherein the cross-sectional area of ​​the bridge portion is configured to be 2% or more and 4% or less of the total cross-sectional area of ​​the current collector.

4. The aforementioned current collector is The battery cell according to claim 1, further comprising a fusing portion provided in the bridge portion and configured to break when an abnormality occurs in the battery cell.

5. Multiple bridge sections are provided, The battery cell according to claim 1, wherein the total cross-sectional area of ​​the multiple bridge portions is configured to be 5% or less of the total cross-sectional area of ​​the current collector.

6. The battery cell according to claim 1, wherein when an abnormality occurs in the battery cell, the fusing time of the current collector is within approximately 20 seconds.

7. The current collector comprises a rim portion located on the outer circumference of the first coupling portion and the second coupling portion, The battery cell according to claim 1, wherein the bridge portion is configured to connect the rim portion and the second coupling portion.

8. The battery cell according to claim 1, wherein the first coupling portion and the second coupling portion are located apart from each other along the radial direction of the electrode assembly.

9. The aforementioned current collector is The battery cell according to claim 8, further comprising a slit line configured to separate the first coupling portion and the second coupling portion from each other.

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

11. An automobile comprising a battery cell according to any one of claims 1 to 9.

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