Secondary battery and manufacturing method thereof

Abstract

Provided is a secondary battery comprising: a first group of unit electrodes and a second group of unit electrodes, which are stacked in a first direction; first electrode tabs extending from one end of the first group of unit electrodes and laminated with one another; second electrode tabs extending from one end of the second group of unit electrodes and laminated with one another; and an electrode lead electrically connected to the first electrode tabs and the second electrode tabs. The first electrode tabs include: a first merge part; a first tab ending part extending substantially parallel to the extension direction of the first group of unit electrodes; and a first connection part connecting the first merge part and the first tab ending part, wherein the first merge part and the first connection part are connected in a V-shape.

Description

Secondary battery and its manufacturing method

[0001] The present invention relates to a secondary battery and a method for manufacturing the same, and more particularly, to a high-capacity secondary battery having a high energy density and a method for manufacturing the same.

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0087158, filed July 2, 2024, the entire disclosure of which is incorporated herein by reference.

[0003] Secondary batteries, unlike non-rechargeable primary batteries, are rechargeable and dischargeable. They are widely used in electronic devices such as mobile phones, laptops, and camcorders, as well as electric vehicles. In particular, lithium secondary batteries have a higher capacity than nickel-cadmium or nickel-hydrogen batteries and a higher energy density per unit weight, leading to a rapid increase in their use.

[0004] Various manufacturing methods have been proposed and applied to manufacture secondary batteries, and various efforts are being made to increase energy density.

[0005] The first technical task to be achieved by the present invention is to provide a high-capacity secondary battery with high energy density.

[0006] The second technical task to be achieved by the present invention is to provide a method for manufacturing a high-capacity secondary battery having a high energy density.

[0007] The present invention provides a secondary battery, which comprises: a first group of unit electrodes and a second group of unit electrodes stacked in a first direction; first electrode tabs extending from one end of the unit electrodes of the first group in a second direction intersecting the first direction and joined to each other; second electrode tabs extending from one end of the unit electrodes of the second group in the second direction and joined to each other; and electrode leads electrically connected to the first electrode tabs and the second electrode tabs, wherein the first electrode tabs include a first merge portion, a first tab ending portion extending in an extending direction of the unit electrodes of the first group, and a first connecting portion connecting the first merge portion and the first tab ending portion, and wherein the first merge portion and the first connecting portion are connected in a V shape.

[0008] In some embodiments, the first merge portion may be a portion of a portion in which all of the first electrode tabs are joined.

[0009] In some embodiments, the inner end of the first merge portion may be substantially positioned at the center of the thickness direction of the unit electrodes of the first group.

[0010] In some embodiments, the outer end of the first merge portion may be located further from the plane between the unit electrodes of the first group and the unit electrodes of the second group than the inner end.

[0011] In some embodiments, the first merge portion and the first connecting portion may form an acute angle of 20 degrees or less.

[0012] In some embodiments, the first connecting portion and the first tab ending portion may have an angle greater than 90 degrees. In some embodiments, the angle between the first connecting portion and the first tab ending portion may be less than 120 degrees.

[0013] In some embodiments, the first electrode tabs and the second electrode tabs may have a cross-sectional shape that is symmetrical with respect to a plane between the unit electrodes of the first group and the unit electrodes of the second group.

[0014] In some embodiments, the second electrode tabs include a second merge portion, a second tab ending portion extending substantially parallel to the extension direction of the second group of unit electrodes, and a second connecting portion connecting the second merge portion and the second tab ending portion, wherein the second merge portion and the second connecting portion can be connected in a V shape.

[0015] In some embodiments, in the thickness direction of the secondary battery, the first tab ending portion and the second tab ending portion may be positioned at substantially the same level.

[0016] In some embodiments, the device further comprises a common electrode portion connected to the first tab ending portion and the second tab ending portion, wherein the first electrode tabs and the second electrode tabs can be connected to the electrode lead through the common electrode portion.

[0017] In some embodiments, the electrode lead is coupled to the common electrode portion, and the electrode lead may be positioned to at least partially overlap the first tab ending portion and the second tab ending portion.

[0018] In some embodiments, the first merge portion and the second merge portion may be offset from each other in a direction perpendicular to the thickness direction of the secondary battery.

[0019] In some embodiments, the first electrode tabs and the second electrode tabs may be arranged so as not to overlap each other in the thickness direction of the secondary battery.

[0020] In some embodiments, the first merge portion and the second merge portion may be symmetrical with respect to a plane between the unit electrodes of the first group and the unit electrodes of the second group.

[0021] In some embodiments, the second merge portion and the second connecting portion may form an acute angle of 20 degrees or less.

[0022] In some embodiments, the first electrode tabs and the second electrode tabs may at least partially overlap in the thickness direction of the secondary battery.

[0023] In some embodiments, the electrode lead may be positioned between the first tab ending portion and the second tab ending portion.

[0024] The present invention provides a first group of unit electrodes and a second group of unit electrodes stacked in a first direction to achieve the second technical task, wherein the first group of unit electrodes is provided with first electrode tabs extending from the unit electrodes of the first group in a second direction intersecting the first direction at one end thereof and joined to each other, and the second group of unit electrodes is provided with second electrode tabs extending from the unit electrodes of the second group in the second direction and joined to each other at one end thereof, and the first electrode tabs include a first merge portion, a first tab ending portion extending in an extension direction of the unit electrodes of the first group, and a first connecting portion connecting the first merge portion and the first tab ending portion, and the second electrode tabs include a second merge portion, a second tab ending portion extending in an extension direction of the unit electrodes of the second group, and a second connecting portion connecting the second merge portion and the second tab ending portion, wherein the first group of unit electrodes and the second group of unit electrodes are provided; A method for manufacturing a secondary battery is provided, comprising: a step of electrically connecting the first tab ending portion and the second tab ending portion to an electrode lead; a step of tilting the first merge portion so that an outer end of the first merge portion moves away from the first tab ending portion around an inner end of the first merge portion; and a step of tilting the second merge portion so that an outer end of the second merge portion moves away from the second tab ending portion around an inner end of the second merge portion.

[0025] In some embodiments, the step of providing the first group of unit electrodes and the second group of unit electrodes may include the step of bending the first electrode tabs joined to each other to form the first merge portion, the first tab ending portion, and the first connecting portion; and the step of bending the second electrode tabs joined to each other to form the second merge portion, the second tab ending portion, and the second connecting portion.

[0026] The secondary battery according to the embodiments of the present invention has the effect of being able to manufacture a high-capacity secondary battery with a high energy density.

[0027] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0028] Figure 1 is a front view showing a secondary battery according to one embodiment of the present invention.

[0029] Figure 2 is a schematic diagram showing the electrode assembly and main components accommodated inside the battery case of the secondary battery of Figure 1.

[0030] Figure 3 is an exploded perspective view of the electrode assembly and main components of Figure 2.

[0031] Fig. 4 is a cross-sectional view showing the electrode assembly and main components illustrated in Fig. 2.

[0032] Figure 5 is an enlarged partial view of part A of Figure 4.

[0033] Figure 6 is a schematic diagram showing an electrode assembly and main components of a secondary battery according to another embodiment of the present invention.

[0034] FIGS. 7A to 11B are schematic diagrams showing a method for manufacturing a secondary battery according to one embodiment of the present invention.

[0035] FIG. 12 is a schematic cross-sectional view showing an exemplary principle in which the first electrode tabs and the second electrode tabs of the cross-sectional shape shown in FIG. 10b are converted into the first electrode tabs and the second electrode tabs of the cross-sectional shape shown in FIG. 11b by an external force.

[0036] FIG. 13 is a perspective view of a battery pack according to exemplary embodiments of the present invention.

[0037] FIG. 14 is a perspective view illustrating some elements of a battery pack according to exemplary embodiments of the present invention.

[0038] Figure 15 is a drawing schematically showing the configuration of a vehicle according to one embodiment of the present invention.

[0039] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention may be modified in various different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. It is preferable to interpret that the embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art. Like numbers refer to like elements throughout. Furthermore, various elements and areas in the drawings are schematically drawn. Therefore, the present invention is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0040] While terms like "first" and "second" may be used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, a first component could be referred to as a "second component," and vice versa, without departing from the scope of the present invention.

[0041] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the inventive concept. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the expressions "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, operations, components, parts, or combinations thereof.

[0042] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Furthermore, it is to be understood that commonly used terms, such as those defined in dictionaries, should be interpreted to have a meaning consistent with their meaning within the relevant technical context, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0043] In some embodiments, where implementations are otherwise feasible, specific process sequences may be performed in a different order than described. For example, two processes described in succession may be performed substantially simultaneously, or in a reverse order from the described order.

[0044] In the accompanying drawings, variations in the shapes depicted may be expected, for example, depending on manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as being limited to the specific shapes of the regions depicted herein, but should include, for example, changes in shapes resulting from the manufacturing process. All terms "and / or" used herein include each and every combination of one or more of the mentioned components. In addition, the term "substrate" used herein may mean the substrate itself, or a laminated structure including the substrate and a predetermined layer or film formed on the surface thereof. In addition, the "surface of the substrate" in this specification may mean the exposed surface of the substrate itself, or the outer surface of a predetermined layer or film formed on the substrate.

[0045]

[0046] (Example 1)

[0047] Figure 1 is a front view showing a secondary battery (100) according to one embodiment of the present invention.

[0048] Referring to FIG. 1, a secondary battery (100) according to one embodiment of the present invention includes an electrode assembly (not shown) including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and a battery case (150) in which the electrode assembly is mounted. Here, the secondary battery (100) may include an electrolyte together with the electrode assembly (not shown) inside the battery case (150).

[0049] For example, the electrolyte refers to a liquid electrolyte, through which ions can move between the positive and negative electrodes, and through this ion exchange between the positive and negative electrodes, the secondary battery can be charged and discharged. Examples of the electrolyte used in the present invention include, but are not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in the manufacture of lithium secondary batteries.

[0050] In addition, the battery case (150) includes a sealing portion (155) having a structure sealed by heat fusion along the outer periphery. The battery case (150) may be a laminate sheet including a resin layer and a metal layer. In some embodiments, the battery case (150) may be formed of a laminate sheet, and may be formed of an outer resin layer forming the outermost layer, a barrier metal layer preventing penetration of a material, and an inner resin layer for sealing. However, the embodiment of the present invention is not limited to the above-described structure, and may be replaced with a battery case of a secondary battery having another general structure.

[0051] Additionally, the electrode assembly (not shown) may be configured in a jelly-roll type (rolled type), stack type (laminated type), or composite type (stack / folded type) structure. More specifically, the electrode assembly (not shown) may include a positive electrode, a negative electrode, and a separator disposed therebetween.

[0052] In addition, in the present embodiment, the battery case (150) may be configured to have a sealed structure in which electrode leads (140) electrically connected to a plurality of electrode tabs (not shown) extending from an electrode assembly (not shown) are exposed to the outside. More specifically, the electrode leads (140) may protrude outwardly of the battery case (150) past the sealing portion (155). In addition, in the present embodiment, a lead film (160) may be positioned between the electrode leads (140) and the sealing portion (155).

[0053] The lead film (160) not only prevents a short circuit from occurring between the electrode lead (140) and the insulating metal layer of the battery case (150), but also improves the sealing property of the battery case (150). When the lead film (160) is provided, the phenomenon of the adhesion being reduced when the electrode lead (140) made of a metal material and the battery case (150) made of a polymer material are thermally bonded can be prevented. In addition, the lead film (160) is preferably made of an insulating material that can block the current from being applied from the electrode lead (140) to the battery case (150). The lead film (160) is made of a film having insulating properties and thermal bonding properties. The lead film (160) may include, for example, one or more material layers selected from polyimide (PI), polypropylene, polyethylene, and polyethylene terephthalate (PET). In some embodiments, the length of the lead film (160) may be increased to prevent short circuiting of the portion of the electrode lead (140) exposed outside the battery case (150).

[0054] In some embodiments, the electrode lead (140) includes an anode lead (141) electrically connected to a cathode tab included in the electrode assembly and a cathode lead (145) electrically connected to a cathode tab included in the electrode assembly.

[0055] In some embodiments, the secondary battery (100) may be a bidirectional pouch battery cell in which a positive electrode lead (141) and a negative electrode lead (145) protrude from each side of a battery case (150). However, the present invention is not limited thereto, and the secondary battery (100) may be a unidirectional pouch battery cell in which a positive electrode lead (141) and a negative electrode lead (145) are arranged together on the same side of the battery case (150). In other embodiments, the secondary battery (100) may be a secondary battery in which an electrode assembly is housed in a square or cylindrical battery case.

[0056] The following description is based on a bidirectional pouch battery cell, but the same or similar description can be applied to a unidirectional pouch battery cell. Those skilled in the art will understand that the following description can also be applied to unidirectional pouch battery cells, prismatic secondary batteries, and cylindrical battery cases.

[0057]

[0058] FIG. 2 is a schematic diagram showing an electrode assembly (101) and main components accommodated inside a battery case (150) of a secondary battery (100) of FIG. 1. FIG. 3 is an exploded perspective view of the electrode assembly (101) and main components of FIG. 2. FIG. 4 is a cross-sectional view showing a cross-section of the electrode assembly (101) and main components illustrated in FIG. 2. FIG. 5 is an enlarged partial view showing part A of FIG. 4.

[0059] Referring to FIGS. 2 to 5, the electrode assembly (101) includes a first group of unit electrodes (111) and a second group of unit electrodes (112) stacked in a first direction (e.g., a thickness direction) along the Z-axis. The first group of unit electrodes (111) and the second group of unit electrodes (112) may extend by a predetermined length in a second direction (e.g., a length direction) along the Y-axis. In some embodiments, the second direction may be any direction intersecting the first direction. The first group of unit electrodes (111) and the second group of unit electrodes (112) may extend by a predetermined width in a third direction (e.g., a width direction) along the X-axis. In some embodiments, the third direction may be any direction intersecting the first direction and the second direction. The unit electrodes (112) of the second group can be stacked while in contact with the unit electrodes (111) of the first group.

[0060] An electrode assembly (101) is formed by alternately laminating electrodes and separators. First, a slurry containing a mixture of an electrode active material, a binder, and a plasticizer is applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, and then this is laminated on both sides of a separator, thereby forming an electrode assembly (101) of a predetermined shape.

[0061] Specifically, the electrode assembly (101) includes two types of electrodes, such as a positive electrode and a negative electrode, and a separator interposed between the electrodes to mutually insulate the electrodes. The electrode assembly (101) includes a stack type, a jelly roll type, a cylindrical type, a stack and folding type, etc. The two types of electrodes, i.e., the positive electrode and the negative electrode, have a structure in which an active material slurry is applied to an electrode current collector in the form of a metal foil or metal mesh containing aluminum and copper, respectively. The slurry can be typically formed by stirring a granular active material, an auxiliary conductor, a binder, a plasticizer, etc. in a state in which a solvent is added. The solvent is removed in a subsequent process.

[0062] The electrode assembly (101) includes electrode tabs (120), as illustrated in FIGS. 2 and 3. The electrode tabs (120) are connected to the positive and negative electrodes of the electrode assembly (101), respectively, and protrude outward from one side of the electrode assembly (101) to serve as a path through which electrons can move between the inside and the outside of the electrode assembly (101). The current collector of the electrode assembly (101) may include a holding portion and a non-coated portion. The holding portion is a portion on which an electrode active material is applied, and the non-coated portion is a portion on which an electrode active material is not applied. The electrode tabs (120) may be formed by cutting the non-coated portion or by connecting a separate conductive member to the non-coated portion by ultrasonic welding, etc. As illustrated in FIGS. 2 and 3, the electrode tabs (120) may protrude in parallel in the same direction from one side of the electrode assembly (101), but are not limited thereto and may protrude in different directions.

[0063] The electrode tabs (120) include first electrode tabs (121) that extend from one end of the unit electrodes (111) of the first group and are joined to each other, and second electrode tabs (122) that extend from one end of the unit electrodes (112) of the second group and are joined to each other.

[0064] The first electrode tabs (121) may include a first merge portion (1212) positioned close to the unit electrodes (111) of the first group, a first tab ending portion (1214) extending substantially parallel to the extension direction of the unit electrodes (111) of the first group, and a first connecting portion (1216) connecting the first merge portion (1212) and the first tab ending portion (1214). In some embodiments, the first tab ending portion (1214) may extend in the extension direction of the unit electrodes (111) of the first group. Here, the extension direction of the unit electrodes (111) of the first group is a direction along the longest dimension of the unit electrodes (111) of the first group.

[0065] In some embodiments, the first merge portion (1212), the first connection portion (1216), and the first tab ending portion (1214) may each be parts of a portion in which the first electrode tabs (121) are overlapped and joined. In particular, in the first merge portion (1212), the electrode tabs of all electrodes belonging to the first group of unit electrodes (111) may be joined.

[0066] The first merge portion (1212) may be adjacent to a terrace portion where the first electrode tabs (121) come together to be joined. The portion of the first electrode tabs (121) that come together and are joined at the terrace portion may be connected to an inner end of the first merge portion (1212). In some embodiments, the inner end may be substantially positioned at the center of the thickness direction of the unit electrodes (111) of the first group.

[0067] In some embodiments, the first merge portion (1212) may extend away from a plane (IP), which is an interface between the first group of unit electrodes (111) and the second group of unit electrodes (112). In some embodiments, the first merge portion (1212) may extend obliquely away from the plane (IP). In some embodiments, an outer end of the first merge portion (1212) may be located further from the plane (IP) than an inner end. The inner end is one end of the first merge portion (1212) that is closer to the first group of unit electrodes (111) before the first electrode tabs (121) are bent. The above outer end is the other end of the first merge portion (1212) and is the end further from the first group of unit electrodes (111) before the first electrode tabs (121) are bent.

[0068] In some embodiments, the first merge portion (1212) may extend in a direction away from the first group of unit electrodes (111). In some embodiments, the first merge portion (1212) may extend in a direction away from the plane (IP) and the first group of unit electrodes (111).

[0069] In some embodiments, the first merge portion (1212) may have a generally flat surface. In some embodiments, the first merge portion (1212) may include a generally flat surface but partially curved with a predetermined curvature.

[0070] In some embodiments, the first connecting portion (1216) may be connected to an outer end of the first merge portion (1212) and may extend toward the plane (IP). One end of the first connecting portion (1216) may be connected to the outer end of the first merge portion (1212) and the other end of the first connecting portion (1216) may extend toward the plane (IP). In some embodiments, the other end of the first connecting portion (1216) may extend at least to a vicinity of the plane (IP). In some embodiments, the other end of the first connecting portion (1216) may extend to the plane (IP).

[0071] In some embodiments, the first connecting portion (1216) may extend toward the plane (IP) and away from the first group of unit electrodes (111). That is, the other end of the first connecting portion (1216) may be located farther away from the first group of unit electrodes (111) than the outer end of the first merge portion (1212). In some embodiments, the first connecting portion (1216) may extend obliquely toward the plane (IP) with respect to the plane (IP). As described above, the first connecting portion (1216) is a part of a portion where the first electrode tabs (121) are overlapped and joined.

[0072] In some embodiments, the first connecting portion (1216) may have a generally flat surface. In some embodiments, the first connecting portion (1216) may include a generally flat surface but partially curved with a predetermined curvature.

[0073] The main plane forming the first connecting portion (1216) and the main plane forming the first merge portion (1212) may be connected in a V shape to form an acute angle with each other. In some embodiments, the main plane forming the first connecting portion (1216) and the main plane forming the first merge portion (1212) may form an acute angle of 20 degrees or less. In some embodiments, the main plane forming the first connecting portion (1216) and the main plane forming the first merge portion (1212) may form an acute angle of 15 degrees or less, 10 degrees or less, or 5 degrees or less.

[0074] In some embodiments, the first connecting portion (1216) and the first merging portion (1212) may form an acute angle at the point where they meet. In some embodiments, the first connecting portion (1216) and the first merging portion (1212) may form an acute angle of 20 degrees or less at the point where they meet. In some embodiments, the first connecting portion (1216) and the first merging portion (1212) may form an acute angle of 15 degrees or less, 10 degrees or less, or 5 degrees or less at the point where they meet.

[0075] In some embodiments, the inner end of the first tab ending portion (1214) may be connected to the other end of the first connecting portion (1216). The first tab ending portion (1214) may extend substantially parallel to the plane (IP). In some embodiments, the first tab ending portion (1214) may extend substantially parallel to the extending direction of the unit electrodes (111) of the first group.

[0076] In some embodiments, the first tab ending portion (1214) may have a generally flat surface. In some embodiments, the first tab ending portion (1214) may include a generally flat surface but partially curved with a predetermined curvature.

[0077] The main plane forming the first connecting portion (1216) and the main plane forming the first tab ending portion (1214) may form an obtuse angle with each other. In some embodiments, the main plane forming the first connecting portion (1216) and the main plane forming the first tab ending portion (1214) may have an angle greater than 90 degrees. In some embodiments, the main plane forming the first connecting portion (1216) and the main plane forming the first tab ending portion (1214) may have an angle less than 120 degrees.

[0078] In some embodiments, the first connecting portion (1216) and the first tab ending portion (1214) may form an obtuse angle at the point where they meet. In some embodiments, the first connecting portion (1216) and the first tab ending portion (1214) may have an angle greater than 90 degrees at the point where they meet. In some embodiments, the first connecting portion (1216) and the first tab ending portion (1214) may have an angle less than 120 degrees at the point where they meet.

[0079]

[0080] The second electrode tabs (122) may include a second merge portion (1222) positioned close to the second group of unit electrodes (112), a second tab ending portion (1224) extending substantially parallel to the extension direction of the second group of unit electrodes (112), and a second connecting portion (1226) connecting the second merge portion (1222) and the second tab ending portion (1224). In some embodiments, the second tab ending portion (1224) may extend in the extension direction of the second group of unit electrodes (112). Here, the extension direction of the second group of unit electrodes (112) is a direction along the longest dimension of the second group of unit electrodes (112).

[0081] In some embodiments, the second merge portion (1222), the second connection portion (1226), and the second tab ending portion (1224) may each be parts of a portion in which the second electrode tabs (122) are overlapped and joined. In particular, in the second merge portion (1222), the electrode tabs of all electrodes belonging to the second group of unit electrodes (112) may be joined.

[0082] The second merge portion (1222) may be adjacent to a terrace portion where the second electrode tabs (122) come together to be joined. The portion of the second electrode tabs (122) that come together and are joined at the terrace portion may be connected to an inner end of the second merge portion (1222). In some embodiments, the inner end may be substantially positioned at the center of the thickness direction of the unit electrodes (112) of the second group.

[0083] In some embodiments, the second merge portion (1222) may extend away from a plane (IP), which is an interface between the second group of unit electrodes (112) and the second group of unit electrodes (112). In some embodiments, the second merge portion (1222) may extend obliquely away from the plane (IP). In some embodiments, an outer end of the second merge portion (1222) may be located further from the plane (IP) than an inner end. The inner end is one end of the second merge portion (1222) that is closer to the second group of unit electrodes (112) before the second electrode tabs (122) are bent. The outer end is the other end of the second merge portion (1222) and is the end further from the second group of unit electrodes (112) before the second electrode tabs (122) are bent.

[0084] In some embodiments, the second merge portion (1222) may extend in a direction away from the second group of unit electrodes (112). In some embodiments, the second merge portion (1222) may extend in a direction away from the plane (IP) and the second group of unit electrodes (112).

[0085] In some embodiments, the second merge portion (1222) may have a generally flat surface. In some embodiments, the second merge portion (1222) may include a generally flat surface but partially curved with a predetermined curvature.

[0086] In some embodiments, the second connecting portion (1226) may be connected to an outer end of the second merge portion (1222) and may extend toward the plane (IP). One end of the second connecting portion (1226) may be connected to the outer end of the second merge portion (1222) and the other end of the second connecting portion (1226) may extend toward the plane (IP). In some embodiments, the other end of the second connecting portion (1226) may extend at least to the vicinity of the plane (IP). In some embodiments, the other end of the second connecting portion (1226) may extend to the plane (IP).

[0087] In some embodiments, the second connecting portion (1226) may extend toward the plane (IP) and away from the second group of unit electrodes (112). That is, the other end of the second connecting portion (1226) may be located farther away from the second group of unit electrodes (112) than the outer end of the second merge portion (1222). In some embodiments, the second connecting portion (1226) may extend obliquely toward the plane (IP) with respect to the plane (IP). As described above, the second connecting portion (1226) is a part of a portion where the second electrode tabs (122) are overlapped and joined.

[0088] In some embodiments, the second connecting portion (1226) may have a generally flat surface. In some embodiments, the second connecting portion (1226) may include a generally flat surface but partially curved with a predetermined curvature.

[0089] The main plane forming the second connecting portion (1226) and the main plane forming the second merge portion (1222) may be connected in a V shape to form an acute angle with each other. In some embodiments, the main plane forming the second connecting portion (1226) and the main plane forming the second merge portion (1222) may form an acute angle of 20 degrees or less. In some embodiments, the main plane forming the second connecting portion (1226) and the main plane forming the second merge portion (1222) may form an acute angle of 15 degrees or less, 10 degrees or less, or 5 degrees or less.

[0090] In some embodiments, the second connecting portion (1226) and the second merging portion (1222) may form an acute angle at the point where they meet. In some embodiments, the second connecting portion (1226) and the second merging portion (1222) may form an acute angle of 20 degrees or less at the point where they meet. In some embodiments, the second connecting portion (1226) and the second merging portion (1222) may form an acute angle of 15 degrees or less, 10 degrees or less, or 5 degrees or less at the point where they meet.

[0091] In some embodiments, the inner end of the second tab ending portion (1224) may be connected to the other end of the second connecting portion (1226). The second tab ending portion (1224) may extend substantially parallel to the plane (IP). In some embodiments, the second tab ending portion (1224) may extend substantially parallel to the extension direction of the second group of unit electrodes (112).

[0092] In some embodiments, the second tab ending portion (1224) may have a generally flat surface. In some embodiments, the second tab ending portion (1224) may include a generally flat surface but partially curved with a predetermined curvature.

[0093] The main plane forming the second connecting portion (1226) and the main plane forming the second tab ending portion (1224) may form an obtuse angle with each other. In some embodiments, the main plane forming the second connecting portion (1226) and the main plane forming the second tab ending portion (1224) may have an angle greater than 90 degrees. In some embodiments, the main plane forming the second connecting portion (1226) and the main plane forming the second tab ending portion (1224) may have an angle less than 120 degrees.

[0094] In some embodiments, the second connecting portion (1226) and the second tab ending portion (1224) may form an obtuse angle at the point where they meet. In some embodiments, the second connecting portion (1226) and the second tab ending portion (1224) may have an angle greater than 90 degrees at the point where they meet. In some embodiments, the second connecting portion (1226) and the second tab ending portion (1224) may have an angle less than 120 degrees at the point where they meet.

[0095]

[0096] In some embodiments, the first electrode tabs (121) and the second electrode tabs (122) may have a cross-sectional shape that is symmetrical with respect to the plane (IP). In some embodiments, the first merge portion (1212) and the second merge portion (1222) may have a cross-sectional shape that is symmetrical with respect to the plane (IP). In some embodiments, the first connecting portion (1216) and the second connecting portion (1226) may have a cross-sectional shape that is symmetrical with respect to the plane (IP). In some embodiments, the first tab ending portion (1214) and the second tab ending portion (1224) may have a cross-sectional shape that is symmetrical with respect to the plane (IP).

[0097]

[0098] In some embodiments, the width of the first tab ending portion (1214) in the third direction may be substantially the same as the width of the second tab ending portion (1224) in the third direction. In some embodiments, the first tab ending portion (1214) and the second tab ending portion (1224) may be spaced apart from each other in the third direction (e.g., the width direction) so as not to overlap each other in the first direction (e.g., the thickness direction). In some embodiments, the first tab ending portion (1214) and the second tab ending portion (1224) may be offset from each other in a direction perpendicular to the first direction along the Z-axis (e.g., the thickness direction) so that there is a portion where they do not overlap each other in the first direction (e.g., the thickness direction).

[0099] In some embodiments, the first tab ending portion (1214) and the second tab ending portion (1224) may be disposed on substantially the same plane. In some embodiments, the first tab ending portion (1214) and the second tab ending portion (1224) may be positioned at substantially the same level in the first direction (e.g., thickness direction) of the secondary battery (100). In some embodiments, the first tab ending portion (1214) and the second tab ending portion (1224) may be disposed on the plane of the interface between the unit electrodes of the first group (111) and the unit electrodes of the second group (112).

[0100] The first electrode tabs (121) and the second electrode tabs (122) are electrically connected to an electrode lead (140). In some embodiments, the first electrode tabs (121) and the second electrode tabs (122) are electrically connected to a common electrode lead (140).

[0101] In some embodiments, the first electrode tabs (121) and the second electrode tabs (122) may be electrically connected to the electrode lead (140) through a common electrode portion (130). In some embodiments, the first electrode tabs (121) may be connected to the common electrode portion (130) at a first tab ending portion (1214). In some embodiments, the second electrode tabs (122) may be connected to the common electrode portion (130) at a second tab ending portion (1224).

[0102] In some embodiments, the common electrode portion (130) may be bonded to the upper surfaces of the first tab ending portion (1214) and the second tab ending portion (1224). In some embodiments, the common electrode portion (130) may be bonded to the lower surfaces of the first tab ending portion (1214) and the second tab ending portion (1224). Here, the 'upper surface' may refer to the visible surface of the first tab ending portion (1214) and the second tab ending portion (1224) illustrated in FIG. 3. In addition, the 'lower surface' herein may refer to the surface opposite to the 'upper surface' of the first tab ending portion (1214) and the second tab ending portion (1224) illustrated in FIG. 3.

[0103] As previously described, the first tab ending portion (1214) and the second tab ending portion (1224) may be arranged on a common plane. Furthermore, the common electrode portion (130) may have a flat plate shape and may be arranged on the common plane.

[0104] In some embodiments, the common electrode portion (130) may at least partially overlap the first tab ending portion (1214) in a first direction (e.g., in a thickness direction). Additionally, the common electrode portion (130) may at least partially overlap the second tab ending portion (1224) in the first direction (e.g., in a thickness direction).

[0105] In some embodiments, the first tab ending portion (1214) and the second tab ending portion (1224) may be joined to one surface of the common electrode portion (130). At this time, an electrode lead (140) may be joined to the other surface of the common electrode portion (130).

[0106] In FIG. 5, a common electrode portion (130) is illustrated as being interposed between the first tab ending portion (1214) and the second tab ending portion (1224) and the electrode lead (140), but in some embodiments, the common electrode portion (130) may be omitted.

[0107] As the demand for high capacity in secondary batteries increases, a large number of unit electrodes are stacked, which increases the thickness of the electrode assembly. If the electrode tabs of the unit electrodes located close to both ends in the thickness direction of the electrode assembly are bent abruptly, the mechanical properties may deteriorate, and if bent at the same angle as before, the lateral dead space increases.

[0108] By making the electrode tabs have a cross-section as described with reference to FIGS. 2 to 5 and by connecting the electrode leads to the terminal portions of the electrode tabs (i.e., the first tab ending portion and the second tab ending portion), the lateral dead space of the secondary battery can be significantly reduced, thereby improving the energy density.

[0109]

[0110] (Example 2)

[0111] FIG. 6 is a schematic diagram showing an electrode assembly (101) and main components of a secondary battery (100) according to another embodiment of the present invention. The embodiment illustrated in FIG. 6 differs from the embodiments illustrated in FIGS. 2 and 3 in the relative positions of the first electrode tabs (121) and the second electrode tabs (122). Therefore, the embodiment illustrated in FIG. 6 will be described below focusing on these differences, and descriptions of overlapping parts will be omitted.

[0112] Referring to FIG. 6, the first electrode tabs (121) and the second electrode tabs (122) may be arranged to at least partially overlap each other in a first direction (e.g., thickness direction) along the Z-axis of the secondary battery (100). That is, in a third direction (e.g., width direction) of the secondary battery (100), the width direction positions of the first electrode tabs (121) and the width direction positions of the second electrode tabs (122) may at least partially overlap each other.

[0113] In some embodiments, the widthwise positions of the first electrode tabs (121) and the widthwise positions of the second electrode tabs (122) may be substantially the same. FIG. 6 illustrates an example in which the widthwise positions of the first electrode tabs (121) and the widthwise positions of the second electrode tabs (122) are the same.

[0114] In some embodiments, the first merge portion (1212) and the second merge portion (1222) may be arranged to at least partially overlap each other in the first direction (e.g., the thickness direction) of the secondary battery (100). That is, in the third direction (e.g., the width direction) of the secondary battery (100), the width direction position of the first merge portion (1212) and the width direction position of the second merge portion (1222) may at least partially overlap each other.

[0115] In some embodiments, the first tab ending portion (1214) and the second tab ending portion (1224) may be arranged to at least partially overlap each other in a first direction (e.g., a thickness direction) of the secondary battery (100). That is, in a third direction (e.g., a width direction) of the secondary battery (100), a width direction position of the first tab ending portion (1214) and a width direction position of the second tab ending portion (1224) may at least partially overlap each other.

[0116] In some embodiments, the electrode lead (140) may be positioned between the ends of the first electrode tabs (121) and the ends of the second electrode tabs (122). In some embodiments, the electrode lead (140) may be positioned between the first tab ending portion (1214) and the second tab ending portion (1224).

[0117] In some embodiments, the electrode lead (140) may be in direct contact with the first tab ending portion (1214) and the second tab ending portion (1224). In some embodiments, the electrode lead (140) may be bonded to the lower surface of the first tab ending portion (1214) and the upper surface of the second tab ending portion (1224).

[0118]

[0119] (Example 3)

[0120] Figures 7a to 11b are schematic diagrams illustrating a method for manufacturing a secondary battery (100) according to one embodiment of the present invention. In particular, Figures 7a, 8a, 9a, 10a, and 11a are perspective views illustrating a manufacturing process of one end portion of an electrode assembly (101). Figures 7b, 8b, 9b, 10b, and 11b are cross-sectional side views illustrating a manufacturing process of one end portion of an electrode assembly (101).

[0121] Referring to FIGS. 7a and 7b, a first group of unit electrodes (111) and a second group of unit electrodes (112) stacked in a first direction (e.g., thickness direction) can be provided.

[0122] The unit electrodes (111) of the first group may be bi-cells and / or mono-cells having a generally identical structure. The unit electrodes (111) of the first group, which are aligned and stacked in a first direction (e.g., a thickness direction), may have first electrode tabs (121) at the same positions in a third direction (e.g., a width direction). The first electrode tabs (121) may extend from one end of the unit electrodes (111) of the first group and be joined to each other.

[0123] The unit electrodes (112) of the second group may be bi-cells and / or mono-cells having a generally identical structure. The unit electrodes (112) of the second group, which are aligned and stacked in a first direction (e.g., a thickness direction), may have second electrode tabs (122) at the same positions in a third direction (e.g., a width direction). The second electrode tabs (122) may extend from one end of the unit electrodes (112) of the second group and be joined to each other.

[0124] The unit electrodes (111) of the first group and the unit electrodes (112) of the second group can be aligned and stacked in the first direction (e.g., thickness direction).

[0125] Although only one side of the electrode assembly (101) is shown in FIG. 7a, a person skilled in the art will understand that the opposite side of the electrode assembly (101) can be configured in the same manner.

[0126] Referring to FIGS. 8A and 8B, the first electrode tabs (121) joined together can be bent to form a first merge portion (1212), a first tab ending portion (1214), and a first connecting portion (1216). At this time, the angle between the first merge portion (1212) and the first connecting portion (1216) can be greater than 90 degrees. For example, the angle between the first merge portion (1212) and the first connecting portion (1216) can be about 95 degrees to about 140 degrees. In addition, the angle between the first tab ending portion (1214) and the first connecting portion (1216) can be greater than 90 degrees. For example, the angle between the first tab ending portion (1214) and the first connecting portion (1216) may be about 95 degrees to about 140 degrees.

[0127] In addition, the second electrode tabs (122) joined to each other can be bent to form a second merge portion (1222), a second tab ending portion (1224), and a second connecting portion (1226). At this time, the angle between the second merge portion (1222) and the second connecting portion (1226) can be greater than 90 degrees. For example, the angle between the second merge portion (1222) and the second connecting portion (1226) can be about 95 degrees to about 140 degrees. In addition, the angle between the second tab ending portion (1224) and the second connecting portion (1226) can be greater than 90 degrees. For example, the angle between the second tab ending portion (1224) and the second connecting portion (1226) can be about 95 degrees to about 140 degrees.

[0128] In some embodiments, the first electrode tabs (121) and the second electrode tabs (122) may be bent simultaneously. In some embodiments, the first electrode tabs (121) and the second electrode tabs (122) may be bent sequentially. In this case, the first electrode tabs (121) may be bent first and then the second electrode tabs (122) may be bent. Alternatively, the second electrode tabs (122) may be bent first and then the first electrode tabs (121) may be bent.

[0129] The interface between the unit electrodes (111) of the first group and the unit electrodes (112) of the second group may be a part of an imaginary plane (IP).

[0130] In some embodiments, the first electrode tabs (121) may be bent so that the first tab ending portion (1214) is positioned on the virtual plane (IP). At this time, a bend portion may be formed between the first merge portion (1212) and the first connecting portion (1216) so that the first merge portion (1212) is generally parallel to the first tab ending portion (1214).

[0131] In some embodiments, the second electrode tabs (122) may be bent so that the second tab ending portion (1224) is positioned on the virtual plane (IP). At this time, a bend portion may be formed between the second merge portion (1222) and the second connecting portion (1226) so that the second merge portion (1222) is generally parallel to the second tab ending portion (1224).

[0132] Here, 'generally parallel' can mean that the angle between the two directions is approximately 20 degrees or less, taking into account tolerances in the manufacturing process.

[0133] In the above, an example of folding the first electrode tabs (121) and the second electrode tabs (122) after stacking the first group of unit electrodes (111) and the second group of unit electrodes (112) has been described, but a person skilled in the art will understand that it is also possible to prepare the first group of unit electrodes (111) having the folded first electrode tabs (121) and the second group of unit electrodes (121) having the folded second electrode tabs (122) and stack the first group of unit electrodes (111) and the second group of unit electrodes (121).

[0134] Referring to FIGS. 9a and 9b, a common electrode portion (130) connecting the first electrode tabs (121) and the second electrode tabs (122) can be provided.

[0135] The common electrode portion (130) may include an electrical conductor that electrically connects the first electrode tabs (121) and the second electrode tabs (122). In some embodiments, the common electrode portion (130) may include copper (Cu), aluminum (Al), iron (Fe), nickel (Ni), tin (Sn), gold (Au), silver (Ag), platinum (Pt), or an alloy including one or more of these.

[0136] In some embodiments, the common electrode portion (130) may have a strip shape extending in a third direction (e.g., width direction). The common electrode portion (130) may be connected to the first tab ending portion (1214) of the first electrode tabs (121) and the second tab ending portion (1224) of the second electrode tabs (122).

[0137] In some embodiments, the common electrode portion (130) may be connected to the first tab ending portion (1214) and the second tab ending portion (1224) by welding. In some embodiments, the common electrode portion (130) may be simultaneously connected to the first tab ending portion (1214) and the second tab ending portion (1224). In some embodiments, the common electrode portion (130) may be sequentially connected to the first tab ending portion (1214) and the second tab ending portion (1224).

[0138] In some embodiments, the first tab ending portion (1214) and the second tab ending portion (1224) may be bonded side by side on the same surface of the common electrode portion (130). In some embodiments, the common electrode portion (130) may be bonded to an upper surface of the first tab ending portion (1214) and an upper surface of the second tab ending portion (1224). In some embodiments, the common electrode portion (130) may be bonded to a lower surface of the first tab ending portion (1214) and a lower surface of the second tab ending portion (1224).

[0139] In some embodiments, the first tab ending portion (1214) and the second tab ending portion (1224) may be bonded side by side on different surfaces of the common electrode portion (130). In some embodiments, the common electrode portion (130) may be bonded to an upper surface of the first tab ending portion (1214) and a lower surface of the second tab ending portion (1224). In some embodiments, the common electrode portion (130) may be bonded to a lower surface of the first tab ending portion (1214) and an upper surface of the second tab ending portion (1224).

[0140] In some embodiments, the step of providing the common electrode portion (130) may be omitted. For example, the first electrode tabs (121) and the second electrode tabs (122) may at least partially overlap in the thickness direction of the electrode assembly (101), in which case the common electrode portion (130) may be omitted.

[0141] Referring to FIGS. 10A and 10B, an electrode lead (140) is connected to the common electrode portion (130). The electrode lead (140) may be a conventional electrode lead known in the art and is not particularly limited.

[0142] The electrode lead (140) may be electrically connected to the first electrode tabs (121) and the second electrode tabs (122). In some embodiments, the electrode lead (140) may be electrically connected to the first tab ending portion (1214) through the common electrode portion (130). In some embodiments, the electrode lead (140) may be electrically connected to the second tab ending portion (1224) through the common electrode portion (130).

[0143] The electrode lead (140) may be connected to the common electrode portion (130), for example, by welding. If the dimension of the electrode lead (140) in the first direction (e.g., width direction) is sufficiently large, the electrode lead (140) may be directly connected to the first electrode tabs (121) and the second electrode tabs (122) without the common electrode portion (130).

[0144] In some embodiments, the first electrode tabs (121) and the second electrode tabs (122) may at least partially overlap in a first direction (e.g., thickness direction) parallel to the Z-axis. That is, when the first electrode tabs (121) and the second electrode tabs (122) are projected in the first direction (e.g., thickness direction), the first electrode tabs (121) and the second electrode tabs (122) may overlap each other. In this case, the electrode lead (140) may be inserted between the first electrode tabs (121) and the second electrode tabs (122). That is, the electrode lead (140) may be inserted between the first tab ending portion (1214) of the first electrode tabs (121) and the second tab ending portion (1224) of the second electrode tabs (122). In some embodiments, the electrode lead (140) may be directly bonded to the lower surface of the first tab ending portion (1214) and the upper surface of the second tab ending portion (1224).

[0145] Referring to FIGS. 11A and 11B, a force (F) may be applied to the first tab ending portion (1214) and the second tab ending portion (1224) in a second direction (e.g., in the longitudinal direction) along the Y-axis to push the first tab ending portion (1214) and the second tab ending portion (1224) toward the electrode assembly (101). To this end, the force (F) may be applied to the electrode lead (140) in the second direction (e.g., in the longitudinal direction). However, the present invention is not limited thereto, and the force (F) may be applied directly to the first tab ending portion (1214) and the second tab ending portion (1224).

[0146] A person skilled in the art will be able to determine the magnitude of the force (F) by considering the mechanical properties of the first electrode tabs (121) and the second electrode tabs (122).

[0147] In some embodiments, the step of applying the force (F) to the first tab ending portion (1214) and the second tab ending portion (1224) may be performed after electrically connecting the first tab ending portion (1214) and the second tab ending portion (1224) to the electrode lead (140).

[0148] In some embodiments, an appropriate force may be applied so that the first merge portion (1212) tilts upward as shown in FIG. 11B. In some embodiments, an appropriate force may be applied so that the second merge portion (1222) tilts downward as shown in FIG. 11B. FIG. 12 is a schematic cross-sectional view illustrating an exemplary principle in which the first electrode tabs (121) and the second electrode tabs (122) of the cross-sectional shape illustrated in FIG. 10B are converted into the first electrode tabs (121) and the second electrode tabs (122) of the cross-sectional shape illustrated in FIG. 11B by an external force.

[0149] Referring to FIG. 12, a force (F) may be applied to the first tab ending portion (1214) and the second tab ending portion (1224). In addition, a predetermined force may be applied upward so that the bent portion between the first merge portion (1212) and the first connection portion (1216) tilts counterclockwise. Furthermore, a predetermined force may be applied downward so that the bent portion between the second merge portion (1222) and the second connection portion (1226) tilts clockwise.

[0150] The angle between the first merge portion (1212) and the first connection portion (1216) may be formed as an acute angle, for example, less than 20 degrees, by the folded portion between the first merge portion (1212) and the first connection portion (1216) rising in a counterclockwise direction. In addition, one end of the first connection portion (1216) may rise and the other end may advance toward the unit electrodes (111, 112). The angle between the first connection portion (1216) and the first tab ending portion (1214) may decrease due to the advancement of the unit electrodes (111, 112), but may still maintain an obtuse angle, for example, less than 120 degrees.

[0151] The angle between the second merge portion (1222) and the second connection portion (1226) can be formed as an acute angle, for example, less than 20 degrees, by lowering the bent portion between the second merge portion (1222) and the second connection portion (1226) in a clockwise direction. In addition, one end of the second connection portion (1226) can be raised and the other end can be advanced toward the unit electrodes (111, 112). The angle between the second connection portion (1226) and the second tab ending portion (1224) can be reduced by the advancement of the unit electrodes (111, 112), but can still be maintained as an obtuse angle, for example, less than 120 degrees.

[0152]

[0153] (Example 4)

[0154] Fig. 13 is a perspective view of a battery pack (1) according to exemplary embodiments of the present invention. Fig. 14 is a perspective view showing some elements of a battery pack (1) according to exemplary embodiments of the present invention.

[0155] Referring to FIGS. 13 and 14, a battery pack (1) may include a lower case (11), secondary batteries (100), a center beam (13), a cross beam (16), a plurality of exhaust devices (14), a pack gasket (165), and an upper case (17). The battery pack (1) may be a final form of a battery system mounted on a mobility device, etc. In addition, the secondary batteries (100) may be one or more types of secondary batteries (100) described with reference to FIGS. 1 to 6.

[0156] The pack housing (20) defining the appearance of the above battery pack (1) may include the lower case (11) and the upper case (17).

[0157] The lower case (11) can provide an internal space (19) for mounting a plurality of secondary batteries (100). In some embodiments, the lower case (11) can include a plate portion (11P) and a side wall (11S). Two directions substantially parallel to the plate portion (11P) are defined as a first direction (e.g., a Z-axis direction) and a second direction (e.g., a Y-axis direction), and a direction substantially perpendicular to the plate portion (11P) of the lower case (11) is defined as a third direction (e.g., an X-axis direction).

[0158] A plurality of secondary batteries (100) may be arranged on a plate portion (11P) of a lower case (11). The plate portion (11P) may support a plurality of secondary batteries (100). The plate portion (11P) may include an upper surface and a lower surface that are substantially parallel. The upper surface of the plate portion (11P) may face the plurality of secondary batteries (100). The lower surface of the plate portion (11P) is the opposite surface of the upper surface of the plate portion (11P).

[0159] The side wall (11S) can horizontally surround a plurality of secondary batteries (100). The side wall (11S) can protect the plurality of secondary batteries (100) in a lateral direction. The side wall (11S) can include a first side wall (11-1), a second side wall (11-2), a third side wall (11-3), and a fourth side wall (11-4). The first to fourth side walls (11-1, 11-2, 11-3, 11-4) can be fixed to each other by a method such as friction stir welding, spot welding, etc., and are not particularly limited thereto.

[0160] The first and second side walls (11-1, 11-2) may be substantially perpendicular to the second direction (e.g., the Y-axis direction). The third and fourth side walls (11-3, 11-4) may be substantially perpendicular to the first direction (e.g., the Z-axis direction). In some embodiments, the first and second side walls (11-1, 11-2) may cover a side surface of the plate portion (11P). In some embodiments, the third and fourth side walls (11-3, 11-4) may be disposed on the plate portion (11P).

[0161] In some embodiments, the first to fourth side walls (11-1, 11-2, 11-3, 11-4) may be provided by an extrusion process. According to exemplary embodiments, the first to fourth side walls (11-1, 11-2, 11-3, 11-4) may include an internal empty space, and thus the side wall (11S) may be lightweight. According to exemplary embodiments, the empty space of the first to fourth side walls (11-1, 11-2, 11-3, 11-4) may be either a venting path for a gas or a channel for a coolant.

[0162] Hereinafter, the technical concept of the present invention will be described with reference to an embodiment in which each of the plurality of secondary batteries (100) does not include a module frame. However, this is a non-limiting example and does not limit the technical concept of the present invention in any way. Those skilled in the art will readily understand a battery pack comprising battery modules that include a module frame that exposes one edge of the battery cells based on the description herein.

[0163] The center beam (13) can isolate elements mounted on the lower case (11) from each other. Accordingly, the center beam (13) can protect a plurality of secondary batteries (100) while preventing unwanted short circuits between them.

[0164] The center beam (13) can extend between the third and fourth side walls (11-3, 11-4). The center beam (13) can extend in a first direction (e.g., in the Z-axis direction). The center beam (13) can contact the third side wall (11-3) and the fourth side wall (11-4). The center beam (13) can isolate the plurality of secondary batteries (100) from each other. The center beam (13) can be interposed between the plurality of secondary batteries (100). In some embodiments, the center beam (13) can divide the internal space (19) into two regions in a second direction (e.g., in the Y-axis direction).

[0165] In some embodiments, the cross beam (16) may be provided to divide the internal space (19) into two or more regions in a first direction (e.g., the Z-axis direction). The cross beam (16) may additionally isolate elements isolated by the center beam (13).

[0166] Some cross beams (16) may extend in a second direction (e.g., in the Y-axis direction) between the center beam (13) and the first side wall (11-1). Other cross beams (16) may extend in a second direction (e.g., in the Y-axis direction) between the center beam (13) and the second side wall (11-2). In some embodiments, the cross beams (16) may be provided to define a space in which a stack of secondary batteries or a group of secondary batteries are accommodated.

[0167] The arrangement of the center beam (13), cross beam (16), and multiple secondary batteries (100) disclosed in FIGS. 13 and 14 are non-limiting examples and do not limit the technical concept of the present invention in any way. A person skilled in the art will readily be able to devise battery packs comprising various arrangements and numbers of center beams and battery cells based on the description herein.

[0168] In some embodiments, a plurality of exhaust devices (14) may be coupled to the fourth side wall (11-4). The fourth side wall (11-4) may include a plurality of exhaust holes connected to the plurality of exhaust devices (14). The plurality of exhaust holes may be configured to provide a path for discharging gases and heat inside the battery pack (1).

[0169] The plurality of exhaust devices (14) may be configured to delay thermal propagation by releasing high-temperature gas inside the battery pack (1) to the outside when at least one of the plurality of secondary batteries (100) is in a thermal runway state.

[0170] Here, thermal runaway of multiple secondary batteries (100) is a state in which temperature changes of multiple secondary batteries (100) further accelerate the temperature change, which is an uncontrollable positive feedback. Multiple secondary batteries (100) in a state of thermal runaway exhibit a rapid temperature increase and can emit a large amount of high-pressure gas and combustion debris.

[0171] The battery pack (1) may further include electrical components. In some embodiments, the electrical components may be mounted on the lower case (11). In some embodiments, the electrical components may be positioned between the fourth side wall (11-4) on which the exhaust devices (14) are installed and the plurality of secondary batteries (100). In some embodiments, the electrical components may include any electronic components necessary to drive the battery pack.

[0172] In some embodiments, the electrical components may include, for example, a battery management system (BMS). The BMS may be configured to monitor, balance, and control the battery pack. In some embodiments, monitoring the battery pack (1) may include measuring the voltage and current of a specific battery cell among a plurality of secondary batteries (100) and measuring the temperature of set locations within the battery pack (1). In some embodiments, the battery pack (1) may include measuring instruments for measuring the voltage, current, and temperature described above.

[0173] Balancing of the above battery pack (1) is an operation to reduce the deviation between the plurality of secondary batteries (100). Control of the above battery pack (1) includes preventing the occurrence of overcharge, overdischarge, and overcurrent. Through monitoring, balancing, and control, the battery pack (1) can operate under optimal conditions, and thus shortening of the lifespan of each of the plurality of secondary batteries (100) can be prevented or reduced.

[0174] The above-described electrical components may further include a cooling device, a PRA (power relay assembly), a safety plug, etc. The cooling device may include a cooling fan. The cooling fan may prevent overheating of each of the plurality of secondary batteries (100) by circulating air inside the battery pack (1). The PRA may be configured to supply or cut off power from the high-voltage battery to an external load (e.g., a motor of a vehicle). The PRA may protect the plurality of secondary batteries (100) and the external load (e.g., a motor of a vehicle) by cutting off power supply to the external load (e.g., a motor of a vehicle) in a situation where an abnormal voltage such as a voltage surge occurs.

[0175] The battery pack (1) may further include a plurality of bus bars configured to electrically connect a plurality of secondary batteries (100). The plurality of secondary batteries (100) may be connected in series and / or in parallel by the plurality of bus bars. Accordingly, the battery pack (1) may be configured to output a high voltage to an external load (e.g., a vehicle motor).

[0176] The gasket (165) may include a material that is elastic in response to applied pressure. The gasket (165) may include, for example, rubber synthesized from a material such as EPDM (ethylene-propylene diene monomer). When the lower case (11) and the upper case (17) are coupled, the gasket (165) may be interposed between the lower case (11) and the upper case (17). The lower case (11) and the upper case (17) may pressurize the gasket (165) so that a certain amount of deformation occurs in the gasket (165). Accordingly, the battery pack (1) may be sealed, and external fluid may be blocked from the internal space of the battery pack (1).

[0177] The upper case (17) may be coupled to the lower case (11). In some embodiments, the upper case (17) may include a main surface and an edge portion. The main surface may cover elements mounted on the battery pack (1), such as a plurality of secondary batteries (100) and electrical components. The edge portion is a surface that comes into contact with the lower case (11). In some embodiments, the upper case (17) may have a flat shape, in which case the edge portion may horizontally surround the main surface. In some embodiments, the main surface may be elevated relative to the edge portion, and the edge portion and the main surface may be connected by a curved portion.

[0178]

[0179] (Example 5)

[0180] Figure 15 is a drawing schematically showing the configuration of a vehicle according to one embodiment of the present invention.

[0181] Referring to FIG. 15, a vehicle (V) according to one embodiment of the present invention may include a battery pack (1) according to one embodiment of the present invention described above. Here, the vehicle (V) may include, for example, a certain vehicle that uses electricity as a driving source, such as an electric vehicle or a hybrid vehicle. In addition to the battery pack (1) according to the present invention, the vehicle (V) may further include various other components included in the vehicle, such as a body or a motor.

[0182] The battery pack (1) can be installed at a predetermined location within the vehicle (V). The battery pack (1) can be used as an electric energy source to provide driving force to the motor of the electric vehicle and drive the vehicle (V). In this case, the battery pack (1) can have a high nominal voltage of 100 V or more.

[0183] The above battery pack (1) can be charged or discharged by an inverter depending on the driving of the motor and / or internal combustion engine. The battery pack (1) can be charged by a regenerative charging device combined with a brake. The battery pack (1) can be electrically connected to the motor of the vehicle (V) via an inverter.

[0184] While the embodiments of the present invention have been described in detail above, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, modifications to future embodiments of the present invention will not depart from the scope of the invention.

[0185]

[0186] [Explanation of symbols]

[0187] 100: Secondary battery

[0188] 101: Electrode Assembly

[0189] 111: Unit electrodes of the 1st Army

[0190] 112: Unit electrodes of the 2nd Army

[0191] 121: First electrode tabs

[0192] 122: Second electrode tabs

[0193] 130: Common electrode section

[0194] 140: Electrode lead

[0195] 141: Positive lead

[0196] 145: Negative lead

[0197] 150: Battery case

[0198] 155: Sealing part

[0199] 160: Lead Film

[0200] 1212: First Merge Division

[0201] 1214: First tap ending

[0202] 1216: First connector

[0203] 1222: Second Merger

[0204] 1224: Second Tap Ending

[0205] 1226: Second connector

Claims

1. Unit electrodes of the first group and unit electrodes of the second group stacked in the first direction; First electrode tabs extending from one end of the unit electrodes of the first group in a second direction intersecting the first direction and joined to each other; Second electrode tabs extending in the second direction from one end of the unit electrodes of the second group and joined to each other; and Electrode leads electrically connected to the first electrode tabs and the second electrode tabs; Including, A secondary battery in which the first electrode tabs include a first merge portion, a first tab ending portion extending in the extension direction of the unit electrodes of the first group, and a first connecting portion connecting the first merge portion and the first tab ending portion, wherein the first merge portion and the first connecting portion are connected in a V shape.

2. In paragraph 1, A secondary battery characterized in that the first merged portion is a part of a portion in which all of the first electrode tabs are joined.

3. In paragraph 2, A secondary battery characterized in that the inner end of the first merge portion is substantially arranged at the center of the thickness direction of the unit electrodes of the first group.

4. In paragraph 3, A secondary battery characterized in that the outer end of the first merge portion is located further from the plane between the unit electrodes of the first group and the unit electrodes of the second group compared to the inner end.

5. In paragraph 1, A secondary battery characterized in that the first merge portion and the first connecting portion form an acute angle of 20 degrees or less.

6. In paragraph 1, A secondary battery characterized in that the first connecting portion and the first tab ending portion have an angle greater than 90 degrees.

7. In paragraph 6, A secondary battery, characterized in that the angle between the first connecting portion and the first tab ending portion is less than 120 degrees.

8. In paragraph 1, A secondary battery characterized in that the first electrode tabs and the second electrode tabs have a symmetrical cross-sectional shape with respect to a plane between the unit electrodes of the first group and the unit electrodes of the second group.

9. In paragraph 1, The second electrode tabs include a second merge portion, a second tab ending portion extending substantially parallel to the extension direction of the second group of unit electrodes, and a second connecting portion connecting the second merge portion and the second tab ending portion, A secondary battery characterized in that the second merge portion and the second connecting portion are connected in a V shape.

10. In paragraph 9, A secondary battery, characterized in that, in the thickness direction of the secondary battery, the first tab ending portion and the second tab ending portion are positioned at substantially the same level.

11. In paragraph 10, Further comprising a common electrode portion connected to the first tab ending portion and the second tab ending portion, A secondary battery characterized in that the first electrode tabs and the second electrode tabs are connected to the electrode lead through the common electrode portion.

12. In paragraph 11, The above electrode lead is coupled to the common electrode portion, A secondary battery, characterized in that the electrode lead is arranged to at least partially overlap the first tab ending portion and the second tab ending portion.

13. In paragraph 9, A secondary battery, characterized in that the first merge portion and the second merge portion are offset from each other in a direction perpendicular to the thickness direction of the secondary battery.

14. In paragraph 13, A secondary battery, characterized in that the first electrode tabs and the second electrode tabs are arranged so as not to overlap each other in the thickness direction of the secondary battery.

15. In paragraph 9, A secondary battery characterized in that the first merge portion and the second merge portion are symmetrical with respect to the plane between the unit electrodes of the first group and the unit electrodes of the second group.

16. In paragraph 15, A secondary battery characterized in that the second merge portion and the second connecting portion form an acute angle of 20 degrees or less.

17. In paragraph 9, A secondary battery, characterized in that the first electrode tabs and the second electrode tabs at least partially overlap in the thickness direction of the secondary battery.

18. In paragraph 17, A secondary battery, characterized in that the electrode lead is positioned between the first tab ending portion and the second tab ending portion.

19. A step of providing a first group of unit electrodes and a second group of unit electrodes stacked in a first direction, wherein the first group of unit electrodes is provided with first electrode tabs extending from the unit electrodes of the first group in a second direction intersecting the first direction and joined to each other at one end thereof, and the second group of unit electrodes is provided with second electrode tabs extending from the unit electrodes of the second group in the second direction and joined to each other at one end thereof, and the first electrode tabs include a first merge portion, a first tab ending portion extending in an extension direction of the unit electrodes of the first group, and a first connecting portion connecting the first merge portion and the first tab ending portion, and the second electrode tabs include a second merge portion, a second tab ending portion extending in an extension direction of the unit electrodes of the second group, and a second connecting portion connecting the second merge portion and the second tab ending portion, the step of providing the first group of unit electrodes and the second group of unit electrodes; A step of electrically connecting the first tab ending portion and the second tab ending portion to an electrode lead; A step of tilting the first merge portion so that the outer end of the first merge portion moves away from the first tab ending portion, with the inner end of the first merge portion as the center; and A step of tilting the second merge portion so that the outer end of the second merge portion moves away from the second tab ending portion, with the inner end of the second merge portion as the center; A method for manufacturing a secondary battery including:

20. In paragraph 19, The step of providing the first group of unit electrodes and the second group of unit electrodes is: A step of bending the first electrode tabs joined to each other to form the first merge portion, the first tab ending portion, and the first connecting portion; and A step of bending the second electrode tabs joined together to form the second merge portion, the second tab ending portion, and the second connecting portion; A method for manufacturing a secondary battery, characterized in that it includes:

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