Battery pack and automobile including same

Abstract

A battery pack according to one embodiment of the present invention includes a plurality of battery cells, a housing that accommodates the plurality of battery cells, a plurality of bus bars that electrically connect the plurality of battery cells, a first weld that connects a first electrode terminal provided on each of the plurality of battery cells to the bus bar, and a second weld that connects a second electrode terminal provided on each of the plurality of battery cells to the bus bar, wherein at least one of the first weld and the second weld includes a region where a laser weld line formed on the bus bar extends in a direction opposite to an extension direction of the weld.

Description

[Technical field]

[0001] The present invention relates to a battery pack having a welded portion with an improved structure, and a vehicle including the battery pack. More specifically, the present invention relates to a battery pack having a welded portion with an improved structure capable of preventing a base material from being penetrated due to an overlap of a weld line and damaging a battery cell when welding a bus bar and a terminal of a battery cell to electrically connect the battery cells, and a vehicle including the battery pack.

[0002] This application claims priority to Korean Patent Application No. 10-2021-0039999, filed on March 26, 2021, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings. [Background technology]

[0003] Secondary batteries, which have high applicability to various products and electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) that are driven by electric drive sources. These secondary batteries have not only the temporary advantage of dramatically reducing the use of fossil fuels, but also the advantage of not producing any by-products associated with energy use, and are therefore attracting attention as a new energy source that is environmentally friendly and improves energy efficiency.

[0004] Currently widely used types of secondary batteries include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, and nickel zinc batteries. The operating voltage of such a unit secondary battery cell, i.e., a unit battery cell, is about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a battery pack may be configured by connecting a plurality of battery cells in series. In addition, a battery pack may be configured by connecting a plurality of battery cells in parallel depending on the charge / discharge capacity required for the battery pack. Therefore, the number of battery cells included in the battery pack may be variously set depending on the required output voltage and / or charge / discharge capacity.

[0005] Meanwhile, when a battery module and / or a battery pack is configured by connecting a plurality of battery cells in series and / or in parallel, a bus bar may be used to electrically connect the plurality of battery cells. In this case, the bus bar may be positioned on the positive and negative terminals of the battery cells, respectively, and then the components may be joined to each other by laser welding. In order to maximize the joining strength by laser welding in a narrow space, it is necessary that the laser welding line is formed over a wide area rather than proceeding in one direction.

[0006] Furthermore, when forming laser weld lines over a wide area in this manner, it is necessary to prevent the overlapping of the laser weld lines from causing penetration of the base material at a specific point. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been devised in consideration of the above-mentioned circumstances, and aims to maximize the bonding force between parts during laser welding and to prevent energy from concentrating at a specific point, which would cause penetration of the base material.

[0008] However, the technical problems that the present invention aims to solve are not limited to the problems described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, a battery pack according to one embodiment of the present invention includes a plurality of battery cells, a housing that accommodates the plurality of battery cells, a plurality of bus bars that electrically connect the plurality of battery cells, a first weld that connects a first electrode terminal provided on each of the plurality of battery cells to the bus bar, and a second weld that connects a second electrode terminal provided on each of the plurality of battery cells to the bus bar, wherein at least one of the first weld and the second weld includes a region where a laser weld line formed on the bus bar extends in a direction opposite to an extension direction of the weld.

[0010] The weld may include an overlap avoidance region that prevents the laser weld lines from creating an overlapping region.

[0011] The bus bar may be disposed on an upper portion of the housing and may electrically connect a plurality of battery cells exposed above the housing.

[0012] The bus bar may include at least one first terminal connection portion coupled to a first electrode terminal of a first battery cell of the plurality of battery cells, and at least one second terminal connection portion coupled to a second electrode terminal of a second battery cell of the plurality of battery cells.

[0013] Each of the plurality of battery cells may include an electrode assembly, a battery can that accommodates the electrode assembly through an opening formed therein and is electrically connected to the electrode assembly, and a top cap that seals the opening and is electrically connected to the electrode assembly.

[0014] The first terminal connection portion may be coupled to the top cap, and the second terminal connection portion may be electrically coupled to the battery can.

[0015] The battery can may include a beading portion formed by pressing around the battery can, and a crimping portion formed on an upper portion of the beading portion, enveloping an outer peripheral surface of the top cap, and extending and bending to cover a portion of an upper surface of the top cap.

[0016] The second terminal connection portion may be coupled to an upper surface of the crimping portion.

[0017] Each of the plurality of battery cells may include a metal washer coupled to an upper surface of the crimping portion and having a width greater than a width of the upper surface of the crimping portion.

[0018] The second terminal connection portion may be coupled to the metal washer.

[0019] Each of the plurality of battery cells may include an electrode assembly, a battery can having an opening formed downward and a closing portion located opposite the opening, housing the electrode assembly through the opening and electrically connected to the electrode assembly, a top cap sealing the opening of the battery can, and a cell terminal exposed to the outside of the battery can through the closing portion and electrically connected to the electrode assembly.

[0020] The first terminal connection portion may be coupled to the cell terminal and the second terminal connection portion may be coupled to the closure portion.

[0021] Meanwhile, a vehicle according to an embodiment of the present invention for solving the above-mentioned problems includes a battery pack according to an embodiment of the present invention as described above. Effect of the Invention

[0022] According to one aspect of the present invention, it is possible to maximize the bonding force between parts during laser welding, and at the same time, it is possible to prevent energy from concentrating at a specific point within the weld where the laser welding is performed, which would cause penetration of the base material.

[0023] However, the advantageous effects obtained through the present invention are not limited to the effects described above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0024] The drawings attached to this specification are intended to illustrate preferred embodiments of the present invention and serve to facilitate a further understanding of the technical ideas of the present invention as well as the content of the invention, and therefore the present invention should not be interpreted as being limited to only the matters depicted in the drawings. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 illustrates a battery pack according to one embodiment of the present invention. [Diagram 2] 2 is an enlarged view of a region A of the battery pack shown in FIG. 1. [Diagram 3] 1 is a cross-sectional view showing a battery cell applied to a battery pack according to an embodiment of the present invention. [Figure 4] 3 is a diagram showing a specific form of the welded portion shown in FIG. 2. [Diagram 5] FIG. 5 is a diagram showing a structure in which the laser weld lines overlap, unlike the weld configuration shown in FIG. 4. [Figure 6] 5 is a diagram showing a modified example of the shape of the welded portion shown in FIG. [Figure 7] 13 is an enlarged view of a portion of a battery pack according to another embodiment of the present invention. FIG. [Figure 8] 11A and 11B are diagrams illustrating a battery cell applied to a battery pack according to another embodiment of the present invention. [Figure 9]13 is an enlarged view of a portion of a battery pack according to still another embodiment of the present invention. FIG. [Figure 10] 13 is a diagram showing a battery cell applied to a battery pack according to still another embodiment of the present invention. FIG. [Figure 11] 1 illustrates a vehicle according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms and words used in this specification and claims are not to be construed as being limited to their ordinary or dictionary meanings, but are to be construed as being in accordance with the meaning and concept of the technical idea of ​​the present invention, in accordance with the principle that the inventor himself can appropriately define the concept of the term in order to best describe the invention. Therefore, it should be understood that the embodiment described in this specification and the configuration shown in the drawings are merely the most preferred embodiment of the present invention, and do not represent the entire technical idea of ​​the present invention, and therefore there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0027] 1 and 2, a battery pack 10 according to one embodiment of the present invention includes a plurality of battery cells 100, a housing 200 that accommodates the plurality of battery cells 100, a plurality of bus bars 300 that electrically connect the plurality of battery cells 100, and a welding portion W that connects electrode terminals T1, T2 provided on the battery cells 100 to the bus bar 300.

[0028] 1 to 3, a cylindrical battery cell may be used as the battery cell 100. In this case, the battery cell 100 includes an electrode assembly 110, a battery can 120, and a top cap 130. The battery cell 100 may further include a gasket 140 in addition to the above-mentioned components.

[0029] Referring to FIG. 3, the electrode assembly 110 includes a first electrode plate having a first polarity, a second electrode plate having a second polarity, and a separator sandwiched between the first and second electrode plates. The electrode assembly 110 may have a jelly-roll shape. That is, the electrode assembly 110 may be manufactured by winding up a stack formed by stacking a first electrode plate, a separator, and a second electrode plate in this order at least once. In this case, a separator may be disposed on the outer periphery of the electrode assembly 110 for insulation from the battery can 120. The first electrode plate is a positive electrode plate or a negative electrode plate, and the second electrode plate corresponds to an electrode plate having a polarity opposite to that of the first electrode plate.

[0030] The first electrode plate includes a first electrode collector and a first electrode active material applied on one or both sides of the first electrode collector. An uncoated portion where the first electrode active material is not applied exists at one end in the width direction (direction aligned with the Z-axis) of the first electrode collector. The uncoated portion functions as a first electrode tab 111. The first electrode tab 111 is disposed at the upper portion in the height direction (direction aligned with the Z-axis) of the electrode assembly 110 accommodated in the battery can 120.

[0031] The second electrode plate includes a second electrode collector and a second electrode active material applied on one or both sides of the second electrode collector. An uncoated portion where the second electrode active material is not applied exists at the other end in the width direction (direction aligned with the Z-axis) of the second electrode collector. The uncoated portion functions as a second electrode tab 112. The second electrode tab 112 is disposed at the lower part in the height direction (direction aligned with the Z-axis) of the electrode assembly 110 accommodated in the battery can 120.

[0032] The battery can 120 is a cylindrical container having an opening at the top and is made of a conductive metal material. The battery can 120 accommodates the electrode assembly 110 through the opening at the top, and also accommodates an electrolyte.

[0033] The battery can 120 is electrically connected to the second electrode tab 112 of the electrode assembly 110. Therefore, the battery can 120 has the same polarity as the second electrode tab 112. As a result, the battery can 120 can function as a first electrode terminal T1 and can be electrically coupled to the second terminal connection portion 320 of the bus bar 300.

[0034] The battery can 120 may include a beading part 121 and a crimping part 122 adjacent to the opening. The beading part 121 is formed on the upper part of the electrode assembly 110. The beading part 121 is formed by pressing around the outer periphery of the battery can 120. The beading part 121 prevents the electrode assembly 110, which has a size corresponding to the width of the battery can 120, from slipping out through the opening at the upper end of the battery can 120, and may function as a support on which a top cap 130 is placed.

[0035] The crimping portion 122 is formed on the upper portion of the beading portion 121. The crimping portion 122 has a shape that is extended and bent so as to enclose the outer peripheral surface of the top cap 130 disposed on the beading portion 121 and to cover a part of the upper surface of the top cap 130.

[0036] The top cap 130 is a part made of a conductive metal material and covers the opening at the top of the battery can 120. The top cap 130 is electrically connected to the first electrode tab 111 of the electrode assembly 110 and is electrically insulated from the battery can 120. Thus, the top cap 130 can function as a first electrode terminal T1 and can be coupled to the first terminal connection portion 310 of the bus bar 300.

[0037] The top cap 130 is placed on a beading portion 121 formed on the battery can 120 and fixed by a crimping portion 122. A gasket 140 may be interposed between the top cap 130 and the crimping portion 122 of the battery can 120 to ensure airtightness of the battery can 120 and to provide electrical insulation between the battery can 120 and the top cap 130.

[0038] The top cap 130 may have a shape in which its center portion is protruded upward. The protruding center portion of the top cap 130 may protrude above the upper end of the battery can 120 to facilitate contact with the bus bar 300 (see FIGS. 1 and 2).

[0039] Meanwhile, as described above, in the cylindrical battery cell 100, the top cap 130 having a first polarity may function as a first electrode terminal T1, and the upper end of the crimping part 122 of the battery can 120 having a second polarity may function as a second electrode terminal T2. That is, the battery cell 100 applied to the battery pack 10 according to an embodiment of the present invention has a structure in which the first electrode terminal T1 having the first polarity and the second electrode terminal T2 having the second polarity are both arranged in the same direction.

[0040] 1 and 2, the housing 200 may accommodate a plurality of battery cells 100 and ensure the rigidity of the battery pack 10. The housing 200 includes a cell support 210 that partially covers an upper portion of the battery cell 100 so that the battery cell 100 accommodated inside the housing 200 does not come off upward.

[0041] The cell support 210 has a plurality of cell exposure holes 210a formed to expose a portion of an upper surface of the battery cell 100 to the outside. A center portion of the top cap 130, i.e., a first electrode terminal T1, is exposed to the upper side of the housing 200 through the cell exposure holes 210a and is coupled to the bus bar 300.

[0042] In addition, the cell support part 210 may have a terminal exposing hole 210b formed on one side of the cell exposing hole 210a. The upper end of the crimping part 122 of the battery can 120, i.e., the second electrode terminal T2, is exposed from the housing 200 through the terminal exposing hole 210b and is coupled to the bus bar 300.

[0043] 1 and 2 , the bus bar 300 is coupled to the battery cells 100 at an upper portion of the battery pack 10 to electrically connect the adjacent battery cells 100. The bus bar 300 includes at least one first terminal connection portion 310 and at least one second terminal connection portion 320.

[0044] The first terminal connection part 310 is coupled to a first electrode terminal T1 of a first battery cell among the plurality of battery cells 100. The second terminal connection part 320 is coupled to a second electrode terminal T2 of a second battery cell adjacent to the first battery cell 100 among the plurality of battery cells 100. That is, the first terminal connection part 310 is coupled to a top cap 130 of the first battery cell exposed upward through a cell exposure hole 210a. Also, the second terminal connection part 320 is coupled to an upper end of a crimping part 122 of the second battery cell exposed upward through a terminal exposure hole 210b. Through such an electrical connection method, the first battery cell and the second battery cell can be connected in series with each other.

[0045] 2 and 4, the welded portion W is formed by laser welding for coupling between the electrode terminals T1, T2 provided on the battery cell 100 and the bus bar 300. Thus, the welded portion W includes laser welded lines L formed in a predetermined pattern on a first terminal connection portion 310 disposed on the first electrode terminal T1 of the battery cell 100 and a second terminal connection portion 320 disposed on the second electrode terminal T2.

[0046] By forming a weld W including the laser welding line L, the first electrode terminal T1 and the first terminal connecting portion 310 are joined to each other, and similarly, the second electrode terminal T2 and the second terminal connecting portion 320 are joined to each other.

[0047] 4, the welded portion W includes a region where the laser weld line L formed on the first terminal connection portion 310 and / or the second terminal connection portion 320 of the bus bar 300 proceeds in a direction opposite to the extension direction of the welded portion W (the direction of the arrow in FIG. 4). That is, the welded portion W having the welding structure of the present invention has a section where the progression direction of the weld line L forming the welded portion W partially proceeds in a direction opposite to the overall extension direction of the welded portion W (the direction of the arrow in FIG. 4). The laser weld line L may have a shape that extends, for example, in a roughly arc shape from one side (the left side when viewed with FIG. 4 as a reference) to the other side (the right side when viewed with FIG. 4 as a reference) in the longitudinal direction of the welded portion W.

[0048] This structure of the weld W improves the bonding strength between the parts by increasing the area where the weld line L is formed, while minimizing the time required for welding, compared to when the weld W is formed by forming the weld W only in the same direction as the overall extension direction of the weld W.

[0049] Meanwhile, the weld W (hereinafter referred to as the first weld) connecting the first electrode terminal T1 and the first terminal connecting portion 310 and / or the weld W (hereinafter referred to as the second weld) connecting the second electrode terminal T2 and the second terminal connecting portion 320 may have an overlap avoidance region P that prevents the laser weld line L from overlapping. In the overlap avoidance region P, the laser weld line L may have a partially discontinuous shape so as not to pass through the same point more than twice.

[0050] As shown in FIG. 5, if there is an area where the laser weld line L temporarily runs in the opposite direction to the overall extension direction of the weld W (the direction of the arrow in FIG. 5), an area where the laser weld lines L overlap may result.

[0051] The welded portion W according to the present invention has an overlap avoidance area P in this manner in order to prevent problems such as damage to parts due to penetration of the base material and leakage of the battery cell 100 that may occur when energy for laser welding is repeatedly applied to a specific area due to the overlap of the laser welding lines L.

[0052] In the cylindrical battery cell, a flat portion formed to be generally aligned with the ground (a surface aligned with the XY plane) may be provided at the upper end of the crimping portion 122 of the battery can 120, and the second terminal connection portion 320 of the bus bar 300 may be joined to the flat portion by welding. The flat portion provided at the upper end of the crimping portion 122 can be used as the second electrode terminal T2, and has a width D1 that is very small compared to the flat portion formed at the upper end of the top cap 130 used as the first electrode terminal T1 to be generally aligned with the ground (a surface aligned with the XY plane). Here, the width of the flat portion formed on the top cap 130 and the width of the crimping portion 122 refer to the length extending along a direction generally aligned with the radial direction of the battery can 120.

[0053] Therefore, in order to couple the second electrode terminal T2 and the second terminal connection portion 320 of the bus bar 300, welding needs to be concentrated in a narrow space. As a result, when a typical welding method is applied, there is a high possibility that the battery can 120 will be penetrated at the upper end of the crimping portion 122 of the battery can 120 coupled with the second terminal connection portion 320 of the bus bar 300. Furthermore, the thickness of the battery can 120 may be limited in consideration of ease of molding and energy density, and therefore may have a smaller thickness than the top cap 130. In this way, when the thickness of the battery can 120 is formed to be thinner than the top cap 130, there is a high possibility that penetration will occur during welding of the crimping portion 122, which is a part of the battery can 120.

[0054] In order to prevent such penetration of the battery can 120, it is highly necessary that the welding method of the present invention as described above is applied particularly to the connection between the second electrode terminal T2 and the bus bar 300. That is, the structure of the weld W in which the weld line L has a section that runs in a direction opposite to the overall progression direction of the weld W may be applied only to the second weld of the first weld and the second weld. Similarly, the structure of the weld W in which the weld line L is configured to have a section that runs in a direction opposite to the overall progression direction of the weld W and has an overlap avoidance region P may be applied only to the second weld of the first weld and the second weld.

[0055] On the other hand, the laser welding line L may progress in a generally arc-like manner to form the welded portion W, as shown in FIG. 4, or, in contrast, may progress in a straight line and repeatedly change direction to form the welded portion W in a generally ribbon-like manner, as shown in FIG. 6.

[0056] Next, a battery pack 10A according to another embodiment of the present invention will be described with reference to Figures 7 and 8. The battery pack 10A according to the other embodiment of the present invention is different from the battery pack 10 according to the embodiment of the present invention described above in that some components are further added to the structure of the battery cell 100A, but the components other than the added components are substantially similar. Therefore, in describing the battery pack 10A according to the other embodiment of the present invention, the components added to the battery cell 100A will be mainly described, and detailed descriptions of other components that are not different from the above-mentioned embodiment will be omitted.

[0057] 7 and 8, a battery cell 100A applied to a battery pack 10A according to another embodiment of the present invention further includes a metal washer 150 having a width D2 larger than the width D1 of the upper surface of the crimping portion 122 of the battery can 120.

[0058] The metal washer 150 is coupled to an upper surface of the crimping portion 122 formed in the battery cell 100A, and functions as a second electrode terminal T2 instead of the crimping portion 122. The metal washer 150 has a shape extending from the crimping portion 122 toward the center of the top cap 130. The metal washer 150 has a width D2 larger than a width D1 of the upper surface of the crimping portion 122 in order to increase the coupling area between the second terminal connection portion 320 of the bus bar 300 and the metal washer 150. As a result of the increased coupling area between the second terminal connection portion 320 and the metal washer 150, a welding process can be smoothly performed, the fastening force between the two components can be improved, and the electrical resistance at the coupling portion can be reduced. When manufacturing a battery pack 10A by electrically connecting a plurality of battery cells 100A having such a structure, the welding structure of the present invention as described above may be applied to the welding portion (first welding portion) W that connects the top cap 130, which functions as the first electrode terminal T1, to the first terminal connection portion 310 and / or the welding portion (second welding portion) W that connects the metal washer 150, which functions as the second electrode terminal T2, to the second terminal connection portion 320.

[0059] Meanwhile, the battery cell 100A may further include an insulating washer 160 interposed between the top cap 130 and the metal washer 150. The insulating washer 160 is made of an insulating material. In the present invention, the top cap 130 functions as a first electrode terminal T1 having a first polarity, and the metal washer 150 functions as a second electrode terminal T2 having a second polarity opposite to the first polarity, so that the top cap 130 and the metal washer 150 must maintain an electrical insulated state. Therefore, it may be advantageous to apply the insulating washer 160 in order to stably maintain such an insulating state.

[0060] The insulating washer 160 is interposed between the lower surface of the metal washer 150 and the top cap 130. As described above, the metal washer 150 has a width D2 larger than the width D1 of the upper surface of the crimping portion 122, and has a shape extending from the crimping portion 122 toward the center of the top cap 130. Therefore, the insulating washer 160 may have a shape extending to cover the inner surface of a hole formed in the center of the metal washer 150 in order to prevent contact between the inner surface of a hole formed in the center of the metal washer 150 and a protrusion formed in the center of the top cap 130.

[0061] Next, a battery pack 10B according to another embodiment of the present invention will be described with reference to Figs. 9 and 10. The battery pack 10B includes a plurality of battery cells 100B electrically connected to each other. The battery pack 10B according to another embodiment of the present invention differs from the battery pack 10 according to the embodiment of the present invention described above in that the structure of some of the battery cells 100B is different, but other elements are substantially similar. Therefore, in describing the battery pack 10B according to another embodiment of the present invention, only the differences will be described, and a description of the substantially same parts as those of the battery pack 10 described above will be omitted.

[0062] The battery cell 100B includes an electrode assembly 110, a battery can 120, a top cap 130, and a cell terminal 170. The battery can 120 includes an opening formed in a lower portion and a closing portion 120a located on the opposite side of the opening. The battery can 120 accommodates the electrode assembly 110 through the opening and is electrically connected to the electrode assembly 110. The battery can 120 may be electrically connected to a second electrode tab 112. In this case, the electrical connection between the second electrode tab 112 and the battery can 120 may be made, for example, via a current collector.

[0063] The top cap 130 is configured to seal the opening of the battery can 120. In the battery cell 100B, unlike the above-described embodiment, the top cap 130 may not be electrically connected to the electrode assembly 110. In this case, the top cap 130 only functions as a component for sealing the opening of the battery can 120, and does not function as an electrode terminal.

[0064] The cell terminal 170 is exposed to the outside of the battery can 120 through the closing portion 120a and is electrically connected to the electrode assembly 110 inside the battery can 120. The cell terminal 170 may be directly or indirectly coupled to a first electrode tab 111 of the electrode assembly 110. The battery cell 100B may further include a gasket interposed between the cell terminal 170 and a through-hole formed in the closing portion 120a for electrical insulation between the cell terminal 170 having a first polarity and the closing portion 120a of the battery can 120 having a second polarity.

[0065] In the battery cell 100B having such a structure, the upper surface of the cell terminal 170 exposed to the outside of the battery can 120 may function as the first electrode terminal T1, and the outer surface of the closing portion 120a of the battery can 120 may function as the second electrode terminal T2. When manufacturing the battery pack 10B by electrically connecting a plurality of the battery cells 100B, the first terminal connection portion 310 of the bus bar 300 may be coupled to the cell terminal (first electrode terminal 170), and the second terminal connection portion (second electrode terminal) 320 of the bus bar 300 may be coupled to the closing portion 120a of the battery can 120. Meanwhile, the welding structure of the present invention as described above may be applied to the welding portion (first welding portion) W that connects the first terminal connection portion 310 and the cell terminal (first electrode terminal) 170 and / or the welding portion (second welding portion) W that connects the second terminal connection portion 320 and the closing portion 120a.

[0066] In manufacturing the battery pack 10B, in order to prevent penetration of the battery can 120, it is highly necessary to apply the above-mentioned welding method of the present invention, particularly to the connection between the second electrode terminal T2 and the bus bar 300. That is, the structure of the weld W in which the weld line L has a section that runs in a direction opposite to the overall progression direction of the weld W may be applied only to the second weld of the first weld and the second weld. Similarly, the structure of the weld W in which the weld line L has a section that runs in a direction opposite to the overall progression direction of the weld W and has an overlap avoidance region P may be applied only to the second weld of the first weld and the second weld.

[0067] 11, an automobile V according to an embodiment of the present invention includes the battery packs 10, 10A, and 10B according to the present invention as described above. The automobile according to an embodiment of the present invention may be, for example, an electric vehicle, and can be operated by receiving power from the battery packs 10, 10A, and 10B according to the present invention.

[0068] Although the present invention has been described above using limited embodiments and drawings, the technical concept of the present invention is in no way limited thereto, and it goes without saying that a person having ordinary knowledge in the technical field to which the present invention pertains can make various modifications and variations within the scope of the technical concept of the present invention and the equivalent scope of the claims. [Explanation of symbols]

[0069] 10, 10A, 10B Battery Pack 100, 100A, 100B Battery Cells 110 Electrode assembly 111 First electrode tab 112 Second electrode tab 120 Battery Can 120a Occlusion 121 Beading section 122 Crimping section 130 Top Cap 140 Gasket T1 1st electrode terminal T2 2nd electrode terminal 150 Metal Washer 160 Insulating washer 170 Cell terminal D1 Width of the crimping part D2 Metal washer width 200 Housing 210 Cell support 210a Cell exposure hole 210b Terminal exposure hole 300 Busbar 310 First terminal connection part 320 Second terminal connection part W Welding L Laser welding line P overlap avoidance area

Claims

1. A plurality of battery cells; a housing that accommodates the plurality of battery cells; A plurality of bus bars electrically connecting the plurality of battery cells; a first welding portion that connects a first electrode terminal provided on each of the plurality of battery cells to the bus bar, and a second welding portion that connects a second electrode terminal provided on each of the plurality of battery cells to the bus bar; Including, At least one of the first welded portion and the second welded portion is a laser weld line formed on the busbar includes a region that runs in a direction opposite to an extension direction of the weld; the welds include overlap avoidance regions that prevent the laser weld lines from creating overlapping regions at regions where the laser weld lines intersect.

2. The bus bar is Located at an upper portion of the housing, The battery pack according to claim 1 , wherein a plurality of battery cells exposed above the housing are electrically connected.

3. The bus bar is at least one first terminal connection portion coupled to a first electrode terminal of a first battery cell among the plurality of battery cells; at least one second terminal connection portion coupled to a second electrode terminal of a second battery cell among the plurality of battery cells; The battery pack of claim 1 or 2, comprising:

4. Each of the plurality of battery cells is An electrode assembly; a battery can that accommodates the electrode assembly through an opening formed in an upper portion and is electrically connected to the electrode assembly; a top cap that seals the opening and is electrically connected to the electrode assembly; 4. The battery pack of claim 3, comprising:

5. the first terminal connection portion is coupled to the top cap; The battery pack according to claim 4 , wherein the second terminal connection portion is electrically coupled to the battery can.

6. The battery can is a beading portion formed by pressing the periphery of the battery can; a crimping portion formed on an upper portion of the beading portion, surrounding an outer peripheral surface of the top cap, and extending and bending the crimping portion to cover a part of an upper surface of the top cap; The battery pack of claim 5 .

7. The second terminal connection portion is The battery pack of claim 6 , wherein the crimping portion is coupled to an upper surface of the battery pack.

8. Each of the plurality of battery cells is 7. The battery pack of claim 6, further comprising a metal washer coupled to an upper surface of the crimping portion and having a width greater than a width of the upper surface of the crimping portion.

9. The second terminal connection portion is The battery pack of claim 8 coupled to the metal washer.

10. Each of the plurality of battery cells is An electrode assembly; a battery can including an opening formed in a lower portion and a closing portion located on an opposite side of the opening, the battery can housing the electrode assembly through the opening and being electrically connected to the electrode assembly; A top cap that seals an opening of the battery can; a cell terminal exposed to the outside of the battery can through the closing portion and electrically connected to the electrode assembly; 4. The battery pack of claim 3, comprising:

11. the first terminal connection portion is coupled to the cell terminal; The battery pack according to claim 10 , wherein the second terminal connection portion is coupled with the closing portion.

12. A motor vehicle comprising a battery pack according to any one of claims 1 to 11.

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