Electrode assembly group and secondary battery comprising same

Abstract

The present invention relates to an electrode assembly group comprising a connection unit which electrically connects a plurality of electrode assemblies inside a pouch and is movable according to a change in the volume of the electrode assemblies, thereby being capable of being prevented from being damaged. An electrode assembly group according to an embodiment of the present invention includes a plurality of electrode assemblies including a plurality of negative electrodes, a positive electrode, and a separator, and a connection unit for electrically connecting the electrode assemblies to each other, in which the connection unit includes a plurality of folds, some of the plurality of folds being folded at a predetermined angle, and the predetermined angle can be changed to allow the electrode assembly to move.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0172746, filed on December 12, 2022, and Korean Patent Application No. 10-2023-0147022, filed on October 30, 2023, which are hereby incorporated by reference in their entirety. Technical Field

[0003] The present invention relates to an electrode assembly group and a secondary battery including the same, and more particularly, to an electrode assembly group for manufacturing a secondary battery capable of charge and discharge and a secondary battery including the same. Background Art

[0004] Recently, due to the depletion of fossil fuels, energy prices have risen, concerns about environmental pollution have increased, and the need for eco-friendly alternative energy sources is essential for future life. Therefore, research on various power generation technologies using solar energy, wind energy, tidal energy, etc. continues, and there is also a continued great interest in power storage systems such as batteries to more efficiently use the electricity generated using these technologies.

[0005] In addition, as the technology of mobile electronic devices and electric vehicles using batteries develops and the demand increases, the demand for batteries as energy sources is rapidly increasing. Therefore, a lot of research is being conducted on batteries that can meet various needs.

[0006] Batteries that store electrical energy can generally be categorized as primary batteries and secondary batteries. Primary batteries are disposable, consumable batteries, while secondary batteries are rechargeable batteries made from materials that undergo a repeatable redox reaction between an electric current and a substance. Specifically, when an electric current is applied to the material, the power source is charged, and when an oxidation reaction is applied to the material, the power source is discharged. This charge-discharge cycle is repeated to generate electricity.

[0007] According to the shape, secondary batteries can be classified into cylindrical cells, pouch cells, prismatic cells, etc. Among these cells, the pouch cell may include an electrode assembly having a shape in which a positive electrode, a negative electrode, a separator, etc. are stacked inside a pouch.

[0008] According to the prior art, one electrode assembly is disposed inside a pouch, but a secondary battery having multiple electrode assemblies disposed inside a pouch to increase energy density has emerged. As the number of electrode assemblies increases, problems arise with the arrangement of the electrode assemblies and the method for electrically connecting the multiple electrode assemblies to each other.

[0009] Therefore, there is a need for an electrode assembly group in which a plurality of electrode assemblies are efficiently disposed and including a component for electrically connecting the plurality of electrode assemblies to each other, and a secondary battery including the same. Summary of the Invention

[0010] Technical issues

[0011] An object of the present invention is to provide an electrode assembly group including a connecting portion, and a secondary battery including the same, which minimizes damage even when the volume of the electrode assembly increases / decreases during charging or discharging of the secondary battery and can effectively electrically connect a plurality of electrode assemblies.

[0012] Technical Solution

[0013] According to an embodiment of the present invention, an electrode assembly group may include: a plurality of electrode assemblies, the plurality of electrode assemblies including a plurality of negative electrodes, positive electrodes and separators; and a connecting portion configured to electrically connect the electrode assemblies to each other, wherein the connecting portion includes a plurality of folding portions, each of the plurality of folding portions having a portion folded at a predetermined angle, and the predetermined angle changes to allow the electrode assembly to move.

[0014] The electrode assembly group may further include an electrode lead electrically connected to the electrode assembly through the connection portion to extend in a direction away from the electrode assembly.

[0015] The connecting portion may include: a lead connecting portion to which the electrode lead is connected; a first folding portion configured to connect an electrode connector of one electrode assembly to the lead connecting portion; and a second folding portion configured to connect an electrode connector of another electrode assembly adjacent to the one electrode assembly to the lead connecting portion, wherein each of the first folding portion and the second folding portion has a shape in which a portion thereof is folded.

[0016] The first folded portion and the second folded portion are arranged in a point-symmetrical shape with respect to the lead connecting portion.

[0017] The electrode assembly group may further include: a first folding portion, which connects the electrode connector of one electrode assembly to the electrode lead; and a second folding portion, which connects the electrode connector of another electrode assembly adjacent to the one electrode assembly to the electrode lead, wherein each of the first folding portion and the second folding portion has a shape in which its portion is folded.

[0018] The first folded portion and the second folded portion are arranged in a point-symmetrical shape with respect to the electrode lead.

[0019] At least one of the first folding portion or the second folding portion may further include: a plurality of members connected to each other to form a specific angle; and a coupling member disposed between the plurality of members and connected to the member adjacent thereto to assist movement of the member.

[0020] The multiple electrode groups may include: a first electrode assembly; and a second electrode assembly, wherein the second electrode assembly is arranged on one side of the first electrode assembly in the thickness direction, wherein, in the first electrode assembly, a first positive electrode tab protrudes from one side of one end of the first electrode assembly in the width direction, and a first negative electrode tab protrudes from the other side of the other end in the width direction, and in the second electrode assembly, a second positive electrode tab protrudes from the other side of one end of the second electrode assembly in the width direction, and a second negative electrode tab protrudes from one side of the other end in the width direction.

[0021] The connection portion may include a negative electrode connection portion electrically connecting the first negative electrode tab and the second negative electrode tab; and a positive electrode connection portion electrically connecting the first positive electrode tab and the second positive electrode tab.

[0022] The electrode assembly may be configured such that the positive electrode tab protrudes from a central portion in the width direction of one end portion and the negative electrode tab protrudes from a central portion in the width direction of the other end portion, and the connecting portion may include: a first folding portion provided at one side of the central portion in the width direction of the electrode assembly; and a second folding portion provided at the other side of the central portion in the width direction of the electrode assembly.

[0023] A secondary battery according to an embodiment of the present invention may include any one of the above-described electrode assembly groups and a battery case in which the electrode assembly group is accommodated.

[0024] In the connection portion, the predetermined angle may be changed to allow the electrode assembly to move in a thickness direction of the electrode assembly and in a width direction perpendicular to the thickness direction.

[0025] An electrode assembly group according to an embodiment of the present invention may include: an electrode assembly unit, the electrode assembly unit including a plurality of electrode assemblies; an electrode lead, the electrode lead being arranged to overlap with a virtual plane passing through the center of the electrode assembly unit in the stacking direction of the electrode assemblies; and a connecting portion, the connecting portion electrically connecting the electrode assembly and each of the electrode leads to each other, wherein the connecting portion includes a plurality of folding portions, each of the plurality of folding portions having a portion folded at a predetermined angle, and the predetermined angle changes to allow the electrode assembly to move.

[0026] Beneficial effects

[0027] The electrode assembly group according to an embodiment of the present invention may include a plurality of electrode assemblies and a connection portion electrically connecting the electrode assemblies to each other, the plurality of electrode assemblies including a plurality of negative electrodes, positive electrodes, and separators. The connection portion may include a plurality of folding portions, each folding portion having a portion folded at a predetermined angle, and the predetermined angle may be changed to allow each of the electrode assemblies to move.

[0028] Therefore, even when a plurality of electrode assemblies are provided inside the battery case, the plurality of electrode assemblies can be electrically connected to each other.

[0029] In addition, since the connection portion can move according to the volume change of the electrode assembly, it is possible to prevent the connection portion from being damaged.

[0030] That is, even when swelling occurs according to use of the secondary battery, damage to the electrode tab and the connection portion can be prevented.

[0031] In addition, the shape of the connection portion can be easily changed, and thus the connection portion can be applied to secondary batteries having various shapes.

[0032] In addition, the electrode taps of the electrode assembly may be disposed to be spaced apart from each other to prevent heat concentration.

[0033] In addition, the arrangement position of the electrode lead may be able to be arranged by the connection portion to improve the efficiency of processes such as bag formation or sealing.

[0034] The effects according to the present invention are not limited to the above-mentioned contents, and include more various effects in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic perspective view illustrating a secondary battery according to one embodiment of the present invention.

[0036] Figure 2 is a perspective view of an electrode assembly group according to one embodiment of the present invention.

[0037] Figure 3 is a plan view of an electrode assembly group according to one embodiment of the present invention.

[0038] Figure 4 is a front view of an electrode assembly group according to one embodiment of the present invention.

[0039] Figure 5 is a side view of a portion of an electrode assembly group according to one embodiment of the present invention.

[0040] Figure 6 is a perspective view of an electrode assembly group according to another embodiment of the present invention.

[0041] Figure 7 is a front view of an electrode assembly group according to another embodiment of the present invention.

[0042] Figure 8 is a perspective view of an electrode assembly group according to another embodiment of the present invention.

[0043] Figure 9 is a front view of an electrode assembly group according to still another embodiment of the present invention. DETAILED DESCRIPTION

[0044] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily practice the present invention. However, the present invention can be implemented in different forms and should not be limited to the embodiments set forth herein.

[0045] In order to clearly describe the present invention, parts that are irrelevant to the description or detailed description of related well-known technologies that may unnecessarily obscure the subject matter of the present invention will be excluded. Throughout the entire specification, the same reference numerals refer to the same elements.

[0046] Furthermore, the terms or words used in the present specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention based on the principle that the inventor can appropriately define terminology concepts to best describe and explain his or her invention.

[0047] Figure 1 is a schematic perspective view illustrating a secondary battery 1 according to one embodiment of the present invention. Figure 2 is a perspective view of an electrode assembly group 10 according to one embodiment of the present invention.

[0048] The present invention provides an electrode assembly group 10 as an embodiment. The electrode assembly group 10 according to the embodiment of the present invention may be an electrode assembly group 10 included in the secondary battery 1. Specifically, the electrode assembly group 10 may be housed inside the battery case 20 during the manufacture of the secondary battery 1.

[0049] Reference Figure 1 The secondary battery 1 including the electrode assembly group 10 according to one embodiment of the present invention may have a shape in which a plurality of electrode assemblies are housed inside the battery case 20. For example, the secondary battery 1 may have a pouch-type battery cell shape, and the battery case 20 may be a pouch. However, this is merely an example, and the electrode assembly group 10 according to an embodiment of the present invention may be applied to secondary batteries having various shapes. That is, the electrode assembly group 10 may be housed in a case having various shapes.

[0050] The electrode assembly group 10 according to the present invention to be described may include a plurality of electrode assemblies. However, in an embodiment of the present invention, an electrode assembly group 10 including two electrode assemblies will be described as an example. That is, in the secondary battery 1 according to an embodiment of the present invention, the electrode assembly group 10 including two electrode assemblies may be housed inside the battery case 20. In addition, the electrode lead 400 connected to the electrode assembly may protrude to the outside of the battery case 20. When the secondary battery 1 is a pouch-type battery cell, since the electrode assembly group 10 includes two electrode assemblies, the battery case 20 may be a pouch including a raised cup portion in each of the two side portions based on the thickness direction thereof.

[0051] Each electrode assembly of the electrode assembly group 10 may include a plurality of negative electrodes, positive electrodes, and separators. For example, the electrode assembly may have a shape in which a plurality of negative electrodes, positive electrodes, and separators, each of which has a plate shape, are stacked on each other. Alternatively, the electrode assembly may have a roll shape in which a plurality of negative electrodes, positive electrodes, and separators, each of which can be wound, are wound.

[0052] As an example of a component for electrically connecting a plurality of electrode assemblies to each other, the electrode assembly group 10 according to an embodiment of the present invention may include a connection portion 300. The connection portion 300 may be electrically connected to each of the electrode assemblies. Here, the connection portion 300 may be made of a conductor as a material that allows current to flow.

[0053] Reference Figure 2, the connecting portion 300 according to one embodiment of the present invention may include a plurality of folding portions for changing its shape. Specifically, each folding portion of the connecting portion 300 may be connected in a folded shape, and its shape may be changed to change the folding angle. Here, the folding angle may be changed to allow the electrode assembly to move. More specifically, the connecting portion 300 may allow the electrode assembly to move in two directions. For example, the two directions may be the thickness direction (e.g., the direction parallel to the Z axis) and the width direction (e.g., the direction parallel to the X axis) of the electrode assembly. The width direction of the electrode assembly may mean a direction perpendicular to the thickness direction. In short, in the folding portion of the connecting portion 300, the folding angle may be changed to allow the electrode assembly to move in the thickness direction and the width direction of the electrode assembly.

[0054] When the secondary battery 1 is repeatedly charged and discharged, a volume change of the electrode assembly caused by an expansion phenomenon may occur. In this regard, as the shape of the folding portion changes so that the folding angle changes, the shape of the connecting portion 300 can change when the volume of the electrode assembly changes. Therefore, even when the volume of the electrode assembly changes, thereby changing the distance between the corresponding electrode joints of the electrode assembly, the shape of the connecting portion 300 can also be changed according to the changed distance. That is, in the electrode assembly group 10 according to the embodiment of the present invention, even when an expansion phenomenon that increases according to the time of use of the secondary battery 1 occurs, the shape of the connecting portion 300 can be easily changed to minimize the impact applied to the connecting portion 300. Therefore, damage to the connecting portion 300 can be minimized, and the life of the secondary battery 1 can be extended. In addition, damage to the electrode lead 400 to be described later due to the change in the shape of the connecting portion 300 can be prevented.

[0055] Figure 3 is a plan view of an electrode assembly group 10 according to one embodiment of the present invention. Figure 4 is a front view of the electrode assembly group 10 according to an embodiment of the present invention. Figure 5 is a side view of an electrode assembly group 10 according to an embodiment of the present invention.

[0056] The electrode assembly group 10 according to one embodiment of the present invention may include a first electrode assembly 100 and a second electrode assembly 200. Here, the second electrode assembly 200 may be provided on one side of the first electrode assembly 100 in the thickness direction, and the first electrode assembly 100 and the second electrode assembly 200 may be stacked on each other. In addition, the first electrode assembly 100 and the second electrode assembly 200 may have substantially similar shapes to be easily accommodated inside the battery case 20.

[0057] As an example of a configuration for preventing heat concentration due to heat generation, in the electrode assembly group 10 according to an embodiment of the present invention, the electrode taps may be spaced apart from each other. Specifically, the positive and negative taps of each electrode assembly may protrude in opposite directions relative to the entire length direction of the electrode assembly (e.g., a direction parallel to the Y axis). In addition, the respective positive taps of the electrode assemblies may be disposed on opposite sides relative to the entire width direction of the electrode assembly (e.g., a direction parallel to the X axis), and the respective negative taps of the electrode assemblies may be disposed on opposite sides relative to the entire width direction of the electrode assembly (e.g., a direction parallel to the X axis).

[0058] Reference Figure 3 , the first electrode assembly 100 may be arranged such that the first positive electrode tab 110 protrudes from one side of one end portion of the first electrode assembly 100 in the width direction, and the first negative electrode tab 120 protrudes from the other side of the other end portion in the width direction. In addition, the second electrode assembly 200 may be arranged such that the second positive electrode tab 210 protrudes from the other side of one end portion of the second electrode assembly 200 in the width direction, and the second negative electrode tab 220 protrudes from one side of the other end portion in the width direction. Figure 3 In the embodiment, the first positive electrode tab 110 may be provided at the lower left end, the second positive electrode tab 210 may be provided at the lower right end, the second negative electrode tab 220 may be provided at the upper left end, and the first negative electrode tab 120 may be provided at the upper right end. In this case, the electrode assembly group 10 may be in a state where the electrode tabs are spaced apart from each other even when viewed from any direction.

[0059] Although not illustrated in one embodiment of the present invention, other arrangements of the electrode tabs for preventing heat concentration may be possible. For example, the first electrode assembly 100 may be arranged so that the first positive electrode tab 110 protrudes from one side of the width direction of one end, and the first negative electrode tab 120 protrudes from one side of the width direction of the other end. In addition, the second electrode assembly 200 may be arranged so that the second positive electrode tab 210 protrudes from the other side of the width direction of one end, and the second negative electrode tab 220 protrudes from the other side of the width direction of the other end. This arrangement can prevent heat generation from being concentrated in a specific portion.

[0060] When using the secondary battery 1, relatively more heat may be generated in the positive and negative electrode tabs, which serve as electrode tabs. Here, when the positive and negative electrode tabs of the electrode assembly are spaced apart from each other, the heat generation points can be dispersed, preventing heat from concentrating in specific areas. Consequently, it is possible to prevent specific areas from losing their function or being physically damaged due to high heat generation.

[0061] As an example of a component for electrically connecting the above-mentioned electrode tabs, the connection portion 300 may include a negative electrode connection portion 320 and a positive electrode connection portion 310. Figure 3 The negative electrode connector 320 can electrically connect the first negative electrode tab 120 and the second negative electrode tab 220, and the positive electrode connector 310 can electrically connect the first positive electrode tab 110 and the second positive electrode tab 210. Specifically, the positive electrode connector 310 can be provided on one end of the first electrode assembly 100 or the second electrode assembly 200, and the negative electrode connector 320 can be provided on the other end of the first electrode assembly 100 or the second electrode assembly 200.

[0062] As an example of a component for electrically connecting to the outside, the electrode assembly group 10 may further include an electrode lead 400. The electrode lead 400 may be electrically connected to the electrode assemblies 100 and 200 through the connection portion 300. That is, the electrode lead 400 may be electrically connected to the positive electrode connection portion 310 or the negative electrode connection portion 320 to have a shape extending in a direction away from the electrode assemblies 100 and 200. Specifically, the electrode lead 400 may be a conductor having a substantially plate-like shape. The electrode lead 400 may connect the electrode assembly group 10 housed inside the battery case 20 to the outside to transmit the electrical energy of the secondary battery 1 to the outside.

[0063] As an example of a component for connecting to the electrode lead 400, the positive electrode connection part 310 or the negative electrode connection part 320 may include a lead connection part 311. In addition, the positive electrode connection part 310 or the negative electrode connection part 320 may include a first folded part 312 and a second folded part 313, each connected to the lead connection part 311.

[0064] Reference Figure 4 and Figure 5 , the electrode lead 400 may be attached to the lead connection portion 311. For example, the electrode lead 400 may be attached to the top surface or the bottom surface of the lead connection portion 311.

[0065] The lead connection portion 311 may have a generally plate-like shape and may be the approximately central portion of the connection portion 300. Specifically, the lead connection portion 311 may be configured so that the electrode lead 400 is disposed at the approximately central portion in the stacking direction of the electrode assembly. That is, due to the lead connection portion 311, the electrode lead 400 may be disposed to overlap with a virtual plane passing through the center of the electrode assembly unit in the stacking direction of the electrode assembly. Here, the electrode assembly unit may refer to a group including the first electrode assembly 100 and the second electrode assembly 200. If the number of electrode assemblies increases, the electrode assembly unit may refer to a group including all electrode assemblies. Since the electrode assembly group 10 according to an embodiment of the present invention includes two electrode assemblies 100 and 200, the electrode lead 400 may be disposed approximately between the first electrode assembly 100 and the second electrode assembly 200 in the stacking direction of the electrode assembly.

[0066] When the electrode lead 400 is disposed at a substantially central portion of the electrode assembly in the stacking direction, the electrode lead 400 can be disposed at a certain distance from each of the positive and negative electrode tabs. That is, heat generation points can be dispersed throughout the electrode assembly group 10, thereby preventing heat from concentrating in a specific portion. Consequently, it is possible to prevent a specific portion of the electrode assembly group 10 from losing its function or being physically damaged due to high heat generation.

[0067] In addition, when the battery case 20 including two cup portions accommodates the electrode assembly group 10, the mold depth of the cup portion at each of the two sides of the battery case 20 can be relatively reduced. Therefore, the efficiency of the process of molding the cup portion can be improved, and the structural stability of the battery case 20 can be improved.

[0068] The first folding portion 312 according to one embodiment of the present invention can connect the electrode tab of one electrode assembly to the lead connection portion 311. In addition, the second folding portion 313 can connect the electrode tab of another electrode assembly to the lead connection portion 311. Here, another electrode assembly may refer to an electrode assembly adjacent to the one electrode assembly. In addition, the electrode tab of one electrode assembly may be the first positive electrode tab 110 or the first negative electrode tab 120 of the first electrode assembly 100 described above, and the electrode tab of the other electrode assembly may be the second positive electrode tab 210 or the second negative electrode tab 220 of the second electrode assembly 200 described above.

[0069] The following description uses the positive electrode connector 310 as an example. The first folded portion 312 may have one portion connected to the first positive electrode tab 110 and another portion connected to the lead connector 311. Specifically, one end of the first folded portion 312 may be connected to the first positive electrode tab 110, and the other end of the first folded portion 312 may be connected to the lead connector 311. For example, one end of the first folded portion 312 may be attached to the upper or lower portion of the first positive electrode tab 110. Furthermore, the second folded portion 313 may have one portion connected to the second positive electrode tab 210 and another portion connected to the lead connector 311. Specifically, one end of the second folded portion 313 may be connected to the lead connector 311, and the other end of the second folded portion 313 may be connected to the second positive electrode tab 210. For example, the other end of the second folded portion 313 may be attached to the upper or lower portion of the second positive electrode tab 210.

[0070] Each of the first folding portion 312 and the second folding portion 313 may have a shape in which a portion thereof is folded. That is, each of the first folding portion 312 and the second folding portion 313 may have a substantially plate shape in which a portion thereof is folded.

[0071] Regarding the arrangement relationship between the first folded portion 312 and the second folded portion 313, the first folded portion 312 and the second folded portion 313 may be arranged in a shape that is substantially point-symmetrical with respect to the lead connection portion 311. When the first folded portion 312 and the second folded portion 313 are arranged point-symmetrically with respect to each other, when the shape of each of the first folded portion 312 and the second folded portion 313 changes due to expansion of the electrode assembly, a relatively structurally stable shape change is performed.

[0072] Hereinafter, a secondary battery 1 in which the electrode assembly group 10 is disposed inside the battery case 20 according to one embodiment of the present invention will be described.

[0073] Since the electrode assembly group 10 inside the secondary battery 1 includes multiple electrode assemblies, the electrode assembly group 10 may include multiple electrode tabs that are spaced apart from each other. Here, the negative electrode connector 320 or the positive electrode connector 310 can electrically connect the negative electrode tabs or the positive electrode tabs that are spaced apart from each other, respectively.

[0074] In the secondary battery 1, the volume of the first electrode assembly 100 or the second electrode assembly 200 may expand due to charging and discharging. Here, the negative electrode connection 320 or the positive electrode connection 310 may receive a tensile force in the direction in which its length extends, and this may cause damage. However, the negative electrode connection 320 or the positive electrode connection 310 of the electrode assembly group 10 according to an embodiment of the present invention may include a first folding portion 312 and a second folding portion 313, each of which has a shape in which its portion is folded. Therefore, when the volume of the first electrode assembly 100 or the second electrode assembly 200 expands, the shape of the folded portion of the first folding portion 312 or the second folding portion 313 may change as the folding angle changes. Therefore, damage to the negative electrode connection 320 or the positive electrode connection 310 can be prevented.

[0075] Since the folding portion, folding degree, arrangement shape, etc. of the first folding portion 312 or the second folding portion 313 are easily changed, the electrode assembly group 10 according to the embodiment of the present invention may be applied to secondary batteries 1 having various shapes.

[0076] Figure 6 is a perspective view of an electrode assembly group 10 ′ according to another embodiment of the present invention. Figure 7 is a front view of an electrode assembly group 10 ′ according to another embodiment of the present invention.

[0077] An electrode assembly group 10' according to another embodiment of the present invention may include a connection portion having another shape. Specifically, the shape of the first folded portion 312' or the second folded portion 313' included in the negative electrode connection portion or the positive electrode connection portion 310' may be different, and the connection portion may electrically connect the electrode assemblies to each other via an electrode lead.

[0078] In this regard, the first folding portion 312' according to another embodiment of the present invention can connect the electrode tab of one electrode assembly and the electrode lead 400 to each other. In addition, the second folding portion 313' can connect the electrode tab of another electrode assembly and the electrode lead 400 to each other. Here, another electrode assembly may refer to an electrode assembly adjacent to the one electrode assembly. In addition, the electrode tab of one electrode assembly may be the first positive electrode tab 110 or the first negative electrode tab 120 of the first electrode assembly 100 described above, and the electrode tab of the other electrode assembly may be the second positive electrode tab 210 or the second negative electrode tab 220 of the second electrode assembly 200 described above.

[0079] The following description will use the positive electrode connector 310' as an example. The first folded portion 312' of the positive electrode connector 310' can have one portion connected to the first positive electrode tab 110 and another portion connected to the electrode lead 400. Specifically, one end of the first folded portion 312' can be connected to the upper portion or the lower portion of the first positive electrode tab 110, and the other end of the first folded portion 312' can be connected to one end of the electrode lead 400. In addition, the second folded portion 313' of the positive electrode connector 310' can have one portion connected to the second positive electrode tab 210 and another portion connected to the electrode lead 400. Specifically, one end of the second folded portion 313' can be connected to the other end of the electrode lead 400, and the other end of the second folded portion 313' can be connected to the upper portion or the lower portion of the second positive electrode tab 210. Therefore, as described above, the first folded portion 312' and the second folded portion 313' of the connector can electrically connect the electrode assemblies to each other via the electrode lead.

[0080] Reference Figure 6 Unlike the connection portion 300 according to one embodiment of the present invention, the connection portion according to another embodiment of the present invention does not include a lead connection portion 311 to which the electrode lead 400 is attached. That is, the connection portion may have a shape in which the electrode lead 400 is directly connected to the first folded portion 312' and the second folded portion 313'. Similar to the first folded portion 312 and the second folded portion 313 according to the embodiment of the present invention, each of the first folded portion 312' and the second folded portion 313' may have a shape in which a portion thereof is folded.

[0081] Reference Figure 7 In order to achieve a relatively stable shape change in structure, the first folded portion 312' and the second folded portion 313' may be arranged in a shape that is substantially point-symmetrical with respect to the electrode lead 400. Here, the electrode lead 400 may be substantially disposed at the center based on the height direction of the electrode assembly (e.g., a direction parallel to the Z axis) and the entire width direction of the electrode assembly (e.g., a direction parallel to the X axis).

[0082] Since the positive electrode connection portion 310 ′ of the electrode assembly group 10 ′ according to another embodiment of the present invention does not include the lead connection portion 311 to which the electrode lead 400 is attached, economic feasibility of processing may be improved.

[0083] Figure 8 is a perspective view of an electrode assembly group 10 - 1 according to yet another embodiment of the present invention. Figure 9 FIG. 1 is a front view of an electrode assembly group 10 - 1 according to yet another embodiment of the present invention.

[0084] An electrode assembly group 10-1 according to another embodiment of the present invention may include a connection portion having another shape according to an electrode tap arranged in another shape. In addition, this embodiment may differ from the above embodiment in that the first folding portion 312-1 includes separate members 3120a and 3120b and a joining member 3121 for connecting the members 3120a and 3120b to each other.

[0085] Reference Figure 8 According to another embodiment of the present invention, the electrode assembly of the electrode assembly group 10-1 may be arranged so that the first positive electrode tab 110-1 and the second positive electrode tab 210-1 may protrude from the center portion in the width direction of one end portion of the electrode assembly, and the first negative electrode tab 120-1 and the second negative electrode tab 220-1 may protrude from the center portion in the width direction of the other end portion. Here, the electrode assembly may be each of the first electrode assembly 100-1 and the second electrode assembly 200-1.

[0086] In addition, in the electrode assembly group 10-1 according to another embodiment of the present invention (the electrode assembly group 10-1 includes an electrode assembly in which the electrode joint is arranged in a shape different from that of other embodiments), since the first folding portion 312-1 and the second folding portion 313-1 each have a folding portion, the shape of the connecting portion can be easily changed.

[0087] According to an embodiment of the present invention, the first folded portion 312-1 and the second folded portion 313-1 can be connected to the lead connection portion 311 of the connection portion 300 and can be directly connected to the electrode lead 400 in the same manner as another embodiment of the present invention. When the latter is described as an example, in the positive electrode connection portion 310-1 connected to the positive electrode tab, the first folded portion 312-1 can have one end connected to the first positive electrode tab 110-1 and the other end connected to one end of the electrode lead 400. In addition, the second folded portion 313-1 can have one end connected to the other end of the electrode lead 400 and the other end connected to the second positive electrode tab 210-1. As above, even if the shape of the electrode assembly is different, the connection portion can be easily applied.

[0088] As an example of a configuration that is easy to change in shape, in a connection portion according to another embodiment of the present invention, the first folding portion 312-1 and the second folding portion 313-1 may be provided at opposite positions. Specifically, the first folding portion 312-1 may be provided on one side of the center portion based on the width direction of the electrode assembly (e.g., a direction parallel to the X-axis), and the second folding portion 313-1 may be provided on the other side of the center portion based on the width direction of the electrode assembly (e.g., a direction parallel to the X-axis).

[0089] When the first folding portion 312-1 and the second folding portion 313-1 are arranged on the same side based on the center portion in the width direction of the electrode assembly, there is a concern that the first folding portion 312-1 and the second folding portion 313-1 will affect each other during the shape change. In addition, since the first folding portion 312-1 and the second folding portion 313-1 are both connected to the same portion of the electrode lead 400, there is a concern that the structural stability will be reduced. Therefore, since the first folding portion 312-1 and the second folding portion 313-1 according to another embodiment of the present invention are respectively arranged at opposite sides based on the center portion in the width direction of the electrode assembly, the structural stability can be improved and the shape can be easily changed.

[0090] Reference Figure 9 , according to another embodiment of the present invention, the first folding portion 312-1 may include components 3120a and 3120b and a joint 3121. Specifically, the components 3120a and 3120b of the first folding portion 312-1 can be arranged in a plurality, so as to be connected to each other and have a specific angle. In addition, the joint 3121 can be arranged between the plurality of components 3120a and 3120b and connected to the components 3120a and 3120b adjacent thereto to assist the components 3120a and 3120b in moving. More specifically, each of the components 3120a and 3120b can have a generally thin plate shape, and the joint 3121 can have a generally cylindrical shape. Therefore, two adjacent components 3120a and 3120b, each having a thin plate shape, can be connected so as to be rotatable along the side surface of the joint 3121 having a cylindrical shape, and therefore move so that the angle formed by the two components 3120a and 3120b changes. Here, similar to the first folding portion 312 - 1 , the second folding portion 313 - 1 may also include members 3120 a and 3120 b and a coupling piece 3121 .

[0091] Since the first folding portion 312 - 1 or the second folding portion 313 - 1 according to still another embodiment of the present invention includes the members 3120 a and 3120 b and the coupling piece 3121 that are separated from each other, movement thereof due to expansion of the electrode assembly may be easier.

[0092] In various embodiments of the present invention, the case where the electrode assembly group includes two electrode assemblies is described as an example. However, this is only an example, and the electrode assembly group may include three or more electrode assemblies. In the case where the electrode assembly group includes three or more electrode assemblies, the number of folding portions, the shape of the connecting portion, etc. may vary.

[0093] Although the present invention has been described with reference to the limited embodiments and drawings, the present invention is not limited thereto and can be variously implemented by those skilled in the art to which the present invention pertains within the technical idea of the present invention and equivalents of the appended claims.

[0094] [Description of the symbol]

[0095] 1: Secondary battery 10, 10', 10-1: Electrode assembly group

[0096] 20: Battery housing 100, 100-1: First electrode assembly

[0097] 110, 110-1: First positive terminal

[0098] 120, 120-1: First negative terminal

[0099] 200, 200-1: Second electrode assembly

[0100] 210, 210-1: Second positive terminal

[0101] 220: Second negative terminal

[0102] 300: Connecting portion 310, 310', 310-1: Positive electrode connecting portion 311: Lead connecting portion 312, 312', 312-1: First folding portion 3120a, 3120b: Component

[0103] 3121 : Joint 313 , 313 ′, 313 - 1 : Second folded portion 320 : Negative electrode connecting portion 400 : Electrode lead.

Claims

1. An electrode assembly group, comprising: a plurality of electrode assemblies, the plurality of electrode assemblies comprising a plurality of negative electrodes, positive electrodes, and separators; as well as a connecting portion configured to electrically connect the electrode assemblies to each other, The connecting portion includes a plurality of folding portions, each of which has a portion folded at a predetermined angle. The predetermined angle is changed to allow the electrode assembly to move. 2 . The electrode assembly group according to claim 1 , further comprising an electrode lead electrically connected to the electrode assembly through the connection portion to extend in a direction away from the electrode assembly.

3. The electrode assembly group according to claim 2, wherein: The connecting portion includes: a lead connection portion to which the electrode lead is connected; a first folded portion configured to connect an electrode tap of one electrode assembly to the lead connection portion; and a second folded portion configured to connect an electrode tap of another electrode assembly adjacent to the one electrode assembly to the lead connection portion, wherein each of the first folded portion and the second folded portion has a shape in which a portion thereof is folded.

4. The electrode assembly group according to claim 3, wherein: The first folded portion and the second folded portion are arranged in a point-symmetrical shape with respect to the lead connecting portion.

5. The electrode assembly group according to claim 2, further comprising: a first folded portion configured to connect an electrode tab of an electrode assembly to the electrode lead; as well as a second folded portion configured to connect an electrode tap of another electrode assembly adjacent to the one electrode assembly to the electrode lead, wherein each of the first folded portion and the second folded portion has a shape in which a portion thereof is folded.

6. The electrode assembly group according to claim 5, wherein: The first folded portion and the second folded portion are arranged in a point-symmetrical shape with respect to the electrode lead.

7. The electrode assembly group according to any one of claims 3 to 6, wherein: At least one of the first folding portion or the second folding portion further includes: a plurality of members connected to each other to form a specific angle; and A coupling member is provided between the plurality of members and is connected to the member adjacent thereto to assist movement of the member.

8. The electrode assembly group according to claim 1, wherein: The plurality of electrode groups include: a first electrode assembly; and a second electrode assembly, the second electrode assembly being disposed on one side of the first electrode assembly in a thickness direction, wherein, in the first electrode assembly, the first positive electrode tab protrudes from one side of one end portion of the first electrode assembly in the width direction, and the first negative electrode tab protrudes from the other side of the other end portion in the width direction, and In the second electrode assembly, the second positive electrode tab protrudes from the other side of one end portion of the second electrode assembly in the width direction, and the second negative electrode tab protrudes from one side of the other end portion in the width direction.

9. The electrode assembly group according to claim 8, wherein: The connecting portion includes: a negative electrode connecting portion configured to electrically connect the first negative electrode tab and the second negative electrode tab to each other; and A positive electrode connecting portion is configured to electrically connect the first positive electrode tab and the second positive electrode tab to each other.

10. The electrode assembly group according to claim 1, wherein: The electrode assembly is arranged so that the positive electrode tab protrudes from a center portion in a width direction of one end portion of the electrode assembly, and the negative electrode tab protrudes from a center portion in the width direction of the other end portion, Wherein, the connecting portion includes: a first folded portion provided at one side of a central portion based on a width direction of the electrode assembly; and A second folded portion is provided at the other side of the center portion based on the width direction of the electrode assembly.

11. A secondary battery, comprising: The electrode assembly according to any one of claims 1 to 10; as well as A battery case houses the electrode assembly group.

12. The electrode assembly group according to claim 1, wherein: In the connection portion, the predetermined angle is changed to allow the electrode assembly to move in a thickness direction of the electrode assembly and in a width direction perpendicular to the thickness direction.

13. An electrode assembly group, comprising: an electrode assembly unit, the electrode assembly unit comprising a plurality of electrode assemblies; an electrode lead disposed so as to overlap with a virtual plane passing through a center of the electrode assembly unit in a stacking direction of the electrode assembly; as well as a connecting portion configured to electrically connect each of the electrode assembly and the electrode lead to each other, The connecting portion includes a plurality of folding portions, each of which has a portion folded at a predetermined angle. The predetermined angle is changed to allow the electrode assembly to move.

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