Battery module and method for manufacturing battery module

Abstract

A battery module and a method of manufacturing the same are capable of improving stability of mechanical and electrical connections. The battery module comprises: a housing; the module bus bar is arranged outside the shell; a battery cell disposed inside the housing; a first bus bar connected to the battery cell and including a first conductive material; and a second bus bar connected to the first bus bar and the module bus bar. The second bus bar includes a second conductive material different from the first conductive material. According to the present disclosure, it is possible to secure stability of mechanical and electrical connections by configuring a member providing an electrical connection between a battery cell inside a battery module and a module bus bar outside the battery module using different materials.

Description

Technical Field

[0001] The present disclosure relates to a battery module and a method of manufacturing the battery module. Background Art

[0002] Unlike primary batteries, which cannot be recharged, secondary batteries can be recharged and discharged. Low-capacity secondary batteries can be used in small portable electronic devices such as smartphones, feature phones, notebook computers, digital cameras, and video cameras. High-capacity secondary batteries are widely used as power sources for driving motors and as power storage batteries in hybrid vehicles or electric vehicles. Secondary batteries include an electrode assembly having a positive electrode and a negative electrode, a housing that accommodates the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] Secondary batteries can be used as battery modules or battery packs formed by connecting multiple unit cells in series and / or parallel to provide high energy density. A battery module or battery pack can be formed by connecting the electrode terminals of multiple unit cells to each other to meet the required amount of power and realize a high-power secondary battery, such as an electric vehicle.

[0004] The above information is disclosed for the purpose of improving understanding of the background of the present disclosure and is not intended to be used for any other purpose. The present disclosure may include information that does not constitute relevant technology. Summary of the Invention

[0005] The present disclosure is directed to providing a battery module and a method for manufacturing the battery module, wherein the battery module can improve the stability of electrical and mechanical connections.

[0006] These and other aspects and features of the present disclosure will be described in, or will be apparent from, the following description of some embodiments of the present disclosure.

[0007] According to aspects of the present disclosure, a battery module is provided, comprising: a housing; a module bus bar disposed on the outside of the housing; a battery cell disposed on the inside of the housing; a first bus bar connected to the battery cell and comprising a first conductive material; and a second bus bar connected to the first bus bar and to the module bus bar, the second bus bar comprising a second conductive material different from the first conductive material.

[0008] The melting point of the second conductive material may be higher than the melting point of the first conductive material.

[0009] The resistivity of the second conductive material may be lower than the resistivity of the first conductive material.

[0010] The first conductive material may include at least one of aluminum (Al) and an aluminum alloy, and the second conductive material may include at least one of copper (Cu) and a copper alloy.

[0011] A first side of the first bus bar may be disposed inside the housing, and a second side of the first bus bar may protrude outside the housing.

[0012] The first bus bar may include a first surface contacting a cell terminal of the battery cell and a second surface opposite to the first surface, and the second bus bar may be stacked on the second surface of the first bus bar.

[0013] A sum of a thickness of the first bus bar and a thickness of the second bus bar may be greater than or equal to 1 mm and less than or equal to 3 mm.

[0014] A ratio of a thickness of the second bus bar to a sum of a thickness of the first bus bar and the thickness of the second bus bar may be greater than or equal to 0.025 and less than or equal to 0.2.

[0015] The thickness of the second bus bar may be greater than or equal to 0.05 mm.

[0016] The first bus bar and the cell terminal may be coupled to each other by laser welding.

[0017] The cell terminal may include the first conductive material.

[0018] The module bus bar may be in contact with the second bus bar.

[0019] The module bus bar may be disposed to face the second surface of the first bus bar, with the second bus bar located between the module bus bar and the second surface of the first bus bar.

[0020] The module bus bar may include the second conductive material.

[0021] The battery module may further include a fixing member for fixing the module bus bar to the second bus bar.

[0022] The fixing member may include a first fixing member passing through the first bus bar, the second bus bar, and the module bus bar; and a second fixing member connected to the first fixing member and configured to press the module bus bar toward the second bus bar.

[0023] According to another aspect of the present disclosure, a method for manufacturing a battery module is provided, the method comprising: disposing a battery cell inside a housing; bringing a first bus bar into contact with a cell terminal of the battery cell; connecting the cell terminal and the first bus bar; bringing a module bus bar into contact with a second bus bar stacked on the first bus bar; and connecting the second bus bar and the module bus bar.

[0024] The connecting of the cell terminal and the first bus bar may be performed by laser welding.

[0025] In the connection of the cell terminal and the first bus bar, a laser beam may be irradiated from the second bus bar in a direction toward the first bus bar.

[0026] An output of the laser beam may be greater than or equal to 3.4 kW and less than or equal to 4.6 kW. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings attached to this specification illustrate some embodiments of the present disclosure and, together with the detailed description of the present disclosure, further describe aspects and features of the present disclosure. However, the present disclosure should not be construed as being limited to the accompanying drawings:

[0028] Figure 1 is a perspective view schematically illustrating a configuration of a battery module according to one embodiment of the present disclosure;

[0029] Figure 2 is an exploded perspective view schematically illustrating the configuration of a battery module according to one embodiment of the present disclosure;

[0030] Figure 3 is a perspective view schematically illustrating a configuration of a battery cell according to one embodiment of the present disclosure;

[0031] Figure 4 is a cross-sectional view schematically illustrating a configuration of a battery cell according to one embodiment of the present disclosure;

[0032] Figure 5 is a perspective view schematically illustrating an installation state of a first bus bar and a second bus bar according to one embodiment of the present disclosure;

[0033] Figure 6 is a perspective view schematically illustrating the configuration of a first bus bar and a second bus bar according to one embodiment of the present disclosure;

[0034] Figure 7 is a bottom perspective view schematically illustrating the configuration of a first bus bar and a second bus bar according to one embodiment of the present disclosure;

[0035] Figure 8is a cross-sectional view schematically illustrating the configuration of a first bus bar and a second bus bar according to one embodiment of the present disclosure;

[0036] Figure 9 is a cross-sectional view schematically illustrating a connection structure between a first bus bar and a battery cell according to one embodiment of the present disclosure;

[0037] Figure 10 is a cross-sectional view schematically illustrating a connection structure of a second bus bar and a module bus bar according to one embodiment of the present disclosure;

[0038] Figure 11 is a flow chart schematically illustrating the sequence of a method for manufacturing a battery module according to one embodiment of the present disclosure;

[0039] Figure 12 is a view schematically illustrating a process of interconnecting a cell terminal and a first bus bar;

[0040] Figure 13 is a view illustrating a welding state of a first bus bar and a cell terminal; and

[0041] Figure 14 is a view schematically illustrating a process of interconnecting the second bus bar and the module bus bar. DETAILED DESCRIPTION

[0042] Herein, some embodiments of the present disclosure will be described in further detail with reference to the accompanying drawings. The terms or words used in this specification and claims should not be interpreted as being limited to common or dictionary meanings, and should be interpreted as meanings and concepts consistent with the technical ideas of the present disclosure based on the principle that the inventor can be his / her own lexicon compiler to appropriately define term concepts.

[0043] The embodiments described in this specification and the configurations shown in the accompanying drawings are provided as some exemplary embodiments of the present disclosure and do not represent all technical ideas, aspects, and features of the present disclosure. Therefore, it should be understood that there may be various equivalents and modifications that can replace or modify the embodiments described herein at the time of filing this application.

[0044] It should be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it can be directly on, connected to, or coupled to the other element or layer, or one or more intervening elements or layers may be present. When an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers. For example, when a first element is described as being “coupled to” or “connected to” a second element, the first element can be directly coupled to or connected to the second element, or the first element can be indirectly coupled to or connected to the second element via one or more intervening elements.

[0045] In the accompanying drawings, the sizes of various elements, layers, etc. may be exaggerated for clarity of illustration. The same reference numerals indicate the same or similar elements. As used herein, the term "and / or" includes any and all combinations of one or more associated listed items. Further, the use of "may" when describing embodiments of the present disclosure relates to "one or more embodiments of the present disclosure." Expressions such as "at least one of..." and "any one of..." modify the entire list of elements when before / after a list of elements, without modifying individual elements in the list. When phrases such as "at least one of A, B, and C," "at least one selected from the group of A, B, and C," or "at least one selected from A, B, and C" are used to specify a list of elements A, B, and C, the phrase may refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the terms "use" and "for" may be considered synonymous with the terms "utilize" and "utilized for," respectively. As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation rather than terms of degree, and are intended to take into account the inherent variations in measurements or calculations that one of ordinary skill in the art would recognize.

[0046] It should be understood that although the terms "first," "second," "third," etc. may be used to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0047] For ease of description, spatially relative terms such as "below," "beneath," "below," "above," "on," etc. may be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures. It should be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figure is turned over, an element or feature described as "below" or "beneath" other elements or features may then be oriented as "above" or "above" the other elements or features. Thus, the term "below" can encompass both above and below orientations. The device may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0048] The terms used herein are for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form "a" and "an" are also intended to include the plural form. It should be further understood that when used in this specification, the terms "comprise" and / or "comprising" specify the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups thereof.

[0049] In addition, any numerical range disclosed and / or listed herein is intended to include all subranges of the same numerical precision contained within the listed range. For example, the range of "1.0 to 10.0" is intended to include (and include) all subranges between the listed minimum value of 1.0 and the listed maximum value of 10.0, i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, for example, such as 2.4 to 7.6. Any maximum numerical limit listed herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit listed in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification, including the claims, to explicitly list any subranges contained within the range explicitly listed herein.

[0050] Referring to two compared elements, features, etc. as "the same" may mean that they are "substantially the same." Thus, the phrase "substantially the same" can include situations with what is considered in the art to be low variance, for example, 5% or less. Furthermore, when a parameter is referred to as being consistent in a given area, this may mean that it is consistent with respect to the average value.

[0051] Throughout the specification, unless otherwise specified, each element may be in the singular or in the plural.

[0052] When any element is referred to as being arranged (or positioned or placed) "on (or under)" or "on (or under)" a component, this may mean that the arbitrary element is placed in contact with the upper surface (or lower surface) of the component, and may also mean that another component may be interposed between the component and any arbitrary element arranged (or positioned or placed) on (or under) the component.

[0053] Furthermore, it should be understood that when an element is referred to as being “coupled,” “linked,” or “connected” to another element, the elements may be directly “coupled,” “linked,” or “connected” to each other, or one or more intermediate elements may exist therebetween through which the element may be “coupled,” “linked,” or “connected” to the other element. Furthermore, when a part is referred to as being “electrically coupled” to another part, the part may be directly electrically connected to the other part, or one or more intermediate parts may exist therebetween so that the part and the other part are indirectly electrically connected to each other.

[0054] Throughout this specification, unless otherwise indicated, when "A and / or B" is stated, it means A, B, or A and B. That is, "and / or" includes any or all combinations of the listed items. Unless otherwise indicated, when "C to D" is stated, it means C or more and D or less.

[0055] The terms used in this specification are used to describe the embodiments of the present disclosure and are not intended to limit the scope of the present disclosure.

[0056] Figure 1 is a perspective view schematically illustrating a configuration of a battery module according to one embodiment of the present disclosure, and Figure 2 is an exploded perspective view schematically illustrating a configuration of a battery module according to one embodiment of the present disclosure.

[0057] refer to Figure 1 and Figure 2 The battery module 1 according to this embodiment may include a housing 100 , a battery cell 200 , a first bus bar 300 , and a second bus bar 400 .

[0058] The housing 100 may support the battery cell 200 and serve as a configuration for protecting the battery cell 200 from external impact or foreign matter. The housing 100 may include a housing body 110 and a housing cover 120. The housing body 110 may provide a space for accommodating the battery cell 200 therein. The housing body 110 may be formed to have a box shape in which the interior is empty and one side is open. Figure 2 , the open side of the housing body 110 may be set to face upward. The cross-sectional shape of the housing body 110 is not limited to Figure 1, and the housing body 110 may be changed in design to have various shapes such as a polygon, a circle, and an ellipse.

[0059] As an example, the housing body 110 may be configured to include a bottom plate 111 and a pair of side plates 112 and a pair of end plates 113 provided to surround an upper space of the bottom plate 111. The pair of side plates 112 may be provided in the width direction of the housing 100 (in the direction based on the width of the housing 100). Figure 1 The pair of end plates 113 may be arranged to face each other in the longitudinal direction of the housing 100 (in the Y-axis direction based on FIG. Figure 1 in the X-axis direction) facing each other.

[0060] The housing cover 120 can enclose the interior space of the housing body 110. As an example, the housing cover 120 can be formed to have a substantially plate shape. The housing cover 120 can be arranged to face the open side of the housing body 110, for example, the upper side surface of the housing body 110. The housing cover 120 can be fixed to the housing body 110 by various types of coupling methods such as bolt coupling, welding coupling, and assembly coupling.

[0061] The battery cell 200 may serve as a unit structure configured to store and supply power in the battery module 1. The battery cell 200 may be provided inside the outer case 100.

[0062] Hereinafter, a case where each of the battery cells 200 is a lithium ion secondary battery and has a prismatic shape will be described as an example. However, the present disclosure is not limited thereto, and the battery cells 200 may be lithium polymer batteries or cylindrical batteries.

[0063] Figure 3 is a perspective view schematically showing a configuration of a battery cell according to one embodiment of the present disclosure, and Figure 4 is a cross-sectional view schematically illustrating a configuration of a battery cell according to one embodiment of the present disclosure.

[0064] refer to Figures 1 to 4 The battery cell 200 may include an electrode assembly 210, a cell case 220, and a cap assembly 230. The electrode assembly 210 may include a positive electrode 211, a negative electrode 212, and a separator 213 disposed between the positive electrode 211 and the negative electrode 212. The positive electrode 211 and the negative electrode 212 may include a coating portion, which is a region where an active material is coated on a current collector formed of a thin metal foil, and uncoated portions 211a and 212a, which are regions where the active material is not coated.

[0065] The electrode assembly 210 may be wound into a core shape after the separator 213 as an insulator is interposed between the positive electrode 211 and the negative electrode 212. However, the electrode assembly 210 is not limited to this shape, and the electrode assembly 210 may have a stacked structure in which the positive electrodes 211 and the negative electrodes 212, each consisting of a plurality of sheets, are alternately stacked with the separator 213 interposed therebetween.

[0066] The electrode assembly 210 may be formed as a single electrode assembly 210 or formed of a plurality of electrode assemblies 210 .

[0067] The cell housing 220 may form the entire exterior of the battery cell 200. The cell housing 220 may house the electrode assembly 210 therein. For example, the cell housing 220 may be formed in a rectangular parallelepiped shape with one surface open. The open surface of the cell housing 220 may be positioned to face the housing cover 120 in the vertical direction within the housing 100. The cell housing 220 may include a conductive metal material such as aluminum, an aluminum alloy, or nickel-plated steel.

[0068] The cap assembly 230 may be coupled to the cell case 220 and may seal the cell case 220 .

[0069] The cover assembly 230 may include a cover plate 231. The cover plate 231 may be formed in a flat plate shape covering the opening of the cell case 220. The cover plate 231 may be coupled to the cell case 220 by various coupling methods such as welding, bolting, and assembly. The cover plate 231 may include a conductive material including at least one of aluminum and an aluminum alloy.

[0070] An electrolyte inlet 231 a in which a sealing cap may be mounted may be formed in the cap plate 231 .

[0071] The cover assembly 230 may further include a single terminal 232. The single terminal 232 may be installed so that the lower end portion passes through the cover plate 231 and the upper end portion protrudes outward from the cover plate 231. The outer peripheral surface of the upper column of the single terminal 232 can be tightened and fixed to the cover plate 231 with a nut. However, the present disclosure is not limited to this, and the single terminal 232 can be riveted or welded to the cover plate 231 by having a riveted structure. The single terminal 232 can be configured to include a first conductive material having conductivity. As an example, the single terminal 232 can be formed entirely of the first conductive material, or can be formed partially of the first conductive material. The first conductive material may include at least one of aluminum (Al) and an aluminum alloy.

[0072] The cell terminals 232 may be provided in pairs. A pair of cell terminals 232 may be connected to the positive electrode 211 and the negative electrode 212 of the electrode assembly 210, respectively. Thus, the pair of cell terminals 232 may serve as the positive and negative terminals of the battery cell 200. As an example, a pair of cell terminals 232 may be electrically connected to the positive electrode current collector 240 and the negative electrode current collector 250 welded to the positive electrode uncoated portion 211a and the negative electrode uncoated portion 212a, respectively. A pair of cell terminals 232 may be welded to the positive electrode current collector 240 and the negative electrode current collector 250. However, the present disclosure is not limited thereto, and the cell terminals 232 may be formed by being integrally combined with the positive electrode current collector 240 and the negative electrode current collector 250.

[0073] The cap assembly 230 may further include an exhaust port 260. The exhaust port 260 may be formed in the cap plate 231. The exhaust port 260 may be opened and closed in conjunction with changes in the internal pressure of the cell housing 220. That is, the exhaust port 260 may seal the cell housing 220 by maintaining a closed state during normal operation of the electrode assembly 210. The exhaust port 260 may be opened when the internal pressure of the cell housing 220 increases to a set level due to overcharging, fire, etc. Emissions such as flames and gases from the interior of the cell housing 220 may be discharged to the outside of the cell housing 220 through the opened exhaust port 260.

[0074] An insulating member formed of an electrically insulating material such as rubber or synthetic resin may be installed between the electrode assembly 210 and the cap plate 231. The insulating member may include a first lower insulating member 60 and a second lower insulating member 70.

[0075] One end of a separating member that may be installed to face one side surface of the electrode assembly 210 may be installed between the insulating member and the cell terminal 232. The separating member may include a first separating member 80 and a second separating member 90. One end of each of the first separating member 80 and the second separating member 90 that may be installed to face one side surface of the electrode assembly 210 may be installed between the first lower insulating member 60 and the second lower insulating member 70 and the pair of cell terminals 232, respectively.

[0076] Therefore, a pair of cell terminals 232 welded to the positive and negative electrode collectors 240 and 250 may be coupled to one ends of both the first and second lower insulating members 60 and 70 and the first and second separating members 80 and 90 , respectively.

[0077] One or more battery cells 200 may be provided. Hereinafter, a case where a plurality of battery cells 200 are provided will be described as an example, but the battery cell 200 is not limited thereto, and a single battery cell 200 may also be provided.

[0078] A plurality of battery cells 200 may be arranged inside the housing 100 in the longitudinal direction (based on the longitudinal direction) of the housing 100. Figure 1 X-axis direction) and width direction (based on Figure 1 In one example, Figure 1 and Figure 2 As shown in FIG, the plurality of battery cells 200 may be arranged in sixteen rows in the longitudinal direction of the housing 100 and in two rows in the width direction of the housing 100. However, the arrangement of the plurality of battery cells 200 is not limited to Figure 1 and Figure 2 and may be varied in design in various ways.

[0079] The plurality of battery cells 200 may be electrically connected to one another via cell bus bars CB. Each cell bus bar CB may electrically connect a pair of battery cells 200 disposed adjacent to one another within the housing 100. As an example, the cell bus bar CB may be made of a conductive material such as aluminum, nickel, copper, or the like. Both sides of the cell bus bar CB may be electrically connected to the cell terminals 232 of a pair of adjacent battery cells 200. The cell bus bar CB may be connected to the cell terminals 232 using various types of joining methods, such as welding and bolting.

[0080] The cell bus bar CB can connect a pair of battery cells 200 disposed adjacent to each other in series or in parallel. For example, the cell bus bar CB can connect a pair of adjacent battery cells 200 in parallel by connecting the cell terminals 232 of the pair of adjacent battery cells 200 that have the same polarity. Alternatively, the cell bus bar CB can connect a pair of adjacent battery cells 200 in series by connecting the cell terminals 232 of the pair of adjacent battery cells 200 that have different polarities.

[0081] A plurality of cell bus bars CB may be provided. The plurality of cell bus bars CB may respectively connect different pairs of battery cells 200 in series or in parallel in the housing 100. The plurality of cell bus bars CB may have various numbers and arrangements depending on the number of battery cells 200, the structure of the series and parallel arrangements between the battery cells 200, and the like.

[0082] Each of the cell bus bars CB may be configured to include a conductive material including at least one of aluminum and an aluminum alloy.

[0083] The cell terminal 232 serving as a positive electrode terminal of one of the plurality of battery cells 200 and the cell terminal 232 serving as a negative electrode terminal of another battery cell 200 may not be connected to the cell bus bar CB.

[0084] The bus bar holder BH may be installed between the housing cover 120 and the battery cells 200. The bus bar holder BH may provide insulation between the battery cells 200 and the cell bus bars CB. The bus bar holder BH may support the cell bus bars CB inside the housing 100. The bus bar holder BH may have a plurality of openings to allow electrical connection between the cell terminals 232 of the battery cells 200 and the cell bus bars CB while blocking electrical interference between the cell bus bars CB and other locations of the battery cells 200 other than the cell terminals 232.

[0085] Although not shown in the drawings, a sensing element (not shown) may be mounted on the bus bar holder BH to collect temperature, current, and voltage status information of the battery cells 200 and control charging and discharging operations of the battery cells 200 based on the collected status information.

[0086] Module bus bars MB may be mounted or disposed on the exterior of the housing 100 to electrically connect adjacent battery modules 1. First and second bus bars 300, 400 may electrically connect the module bus bars MB to the battery cells 200 of any one battery module 1. That is, the first and second bus bars 300, 400 may serve as external connection terminals for the battery module 1. The first and second bus bars 300, 400 may be integrally coupled to form a single assembly.

[0087] The assembly formed by the first bus bar 300 and the second bus bar 400 may be provided in pairs. Each assembly formed by the first bus bar 300 and the second bus bar 400 may be connected to a cell terminal 232 serving as a positive electrode terminal of one battery cell 200 and a cell terminal 232 serving as a negative electrode terminal of another battery cell 200, respectively, and may be used as a positive electrode terminal or a negative electrode terminal of the battery module 1.

[0088] Figure 5 is a perspective view schematically illustrating an installation state of a first bus bar and a second bus bar according to one embodiment of the present disclosure, Figure 6 is a perspective view schematically illustrating the configuration of a first bus bar and a second bus bar according to one embodiment of the present disclosure, Figure 7 is a bottom perspective view schematically illustrating the configuration of a first bus bar and a second bus bar according to one embodiment of the present disclosure, and Figure 8 is a cross-sectional view schematically illustrating the configuration of a first bus bar and a second bus bar according to one embodiment of the present disclosure.

[0089] refer to Figures 1 to 8 , the first bus bar 300 may be connected to the battery cell 200 .

[0090] One side of the first bus bar 300 according to the present embodiment is disposed inside the housing 100, and the other side of the first bus bar 300 may protrude outside the housing 100. As an example, the first bus bar 300 may be formed to include a bar having a first end portion 310 disposed inside the housing 100 and a second end portion 320 disposed outside the housing 100.

[0091] The second end portion 320 may be provided at a lower position than the first end portion 310. Thus, the central portion 330 of the first bus bar 300 may extend downward from the first end portion 310 to the second end portion 320 in a curved shape. The second end portion 320 protruding to the outside of the housing 100 may be supported by being seated on a bracket or the like separately mounted on the housing body 110.

[0092] The first bus bar 300 may include a first surface 301 and a second surface 302 disposed opposite to each other. As an example, the first surface 301 and the second surface 302 may be perpendicular to each other based on the Figure 1 In this case, the first surface 301 and the second surface 302 may refer to a lower surface and an upper surface of the first bus bar 300 , respectively.

[0093] Figure 9 is a cross-sectional view schematically illustrating a connection structure between a first bus bar and a battery cell according to one embodiment of the present disclosure.

[0094] refer to Figures 1 to 9 , the first surface 301 located on one side of the first end portion 310 of the first bus bar 300 can be set to face the cell terminal 232 of any one battery cell 200 that is not connected to the cell bus bar CB. The first surface 301 located on this side of the first end portion 310 can be in contact with the cell terminal 232. The first bus bar 300 can be bonded to the cell terminal 232 by laser welding while the first surface 301 is in contact with the cell terminal 232. As described above, since the first bus bar 300 is directly connected to the cell terminal 232 without utilizing any additional components, the overall size of the connection structure between the battery cell 200 and the first bus bar 300 can be reduced, and the spatial freedom of design of the battery module 1 can be improved.

[0095] The first busbar 300 can be formed from a conductive material. As an example, the first busbar 300 can be formed from the same material as the cell terminals 232. That is, the first busbar 300 can be configured to include a first conductive material that includes at least one of aluminum and an aluminum alloy. In this case, the first busbar 300 can be formed entirely from the first conductive material. Alternatively, the first busbar 300 can be formed so that only the portion that directly contacts the cell terminals 232 is formed from the first conductive material. Since the first busbar 300 and the cell terminals 232 are formed from the same material as described above, a high weld strength can be achieved between the first busbar 300 and the cell terminals 232.

[0096] The second bus bar 400 can be connected to the first bus bar 300 and the module bus bar MB. That is, the second bus bar 400 can serve as a component that forms an electrical connection path between the module bus bar MB and the first bus bar 300. The second bus bar 400 can be formed in the form of a sheet stacked on the second surface 302 of the first bus bar 300. The area of ​​the second bus bar 400 can be formed to be the same as the area of ​​the second surface 302. That is, the second bus bar 400 can be formed to completely cover the second surface 302 across the entire first end portion 310, the second end portion 320, and the center portion 330 of the first bus bar 300. The first bus bar 300 and the second bus bar 400 can be integrally bonded by various types of bonding methods such as thermal compression or welding.

[0097] Figure 10 is a cross-sectional view schematically illustrating a connection structure of a second bus bar and a module bus bar according to one embodiment of the present disclosure.

[0098] refer to Figures 1 to 10 , the module bus bar MB may face the second surface 302 of the first bus bar 300, wherein the second bus bar 400 is interposed between the module bus bar MB and the second surface 302 at one side of the second end portion 320 of the first bus bar 300. The module bus bar MB may be directly in contact with the second bus bar 400 by being placed on the second bus bar 400. The second bus bar 400 and the module bus bar MB may be connected to each other by a fixing member 500 to be described below. Alternatively, the second bus bar 400 and the module bus bar MB may also be integrally connected by welding, hot pressing, or the like.

[0099] The second bus bar 400 can be formed of a conductive material to electrically connect to the first bus bar 300 and the module bus bar MB. As an example, the second bus bar 400 can be configured to include a second conductive material different from the first conductive material. The module bus bar MB can be configured to include the same second conductive material as in the second bus bar 400. The second conductive material can be a material having a relatively lower resistivity than the first conductive material. Therefore, the module bus bar MB and the second bus bar 400 can form a high-output and high-capacity conductive path per battery module 1. In addition, since the second bus bar 400 and the module bus bar MB are formed of the same material, the surface resistance in the contact area between the second bus bar 400 and the module bus bar MB can be reduced.

[0100] The second conductive material may have a higher melting point than the first conductive material. In this case, when laser welding is performed on the first bus bar 300 and the cell terminals 232, the second bus bar 400, which is positioned to cover the laser-irradiated surface of the first bus bar 300, may melt relatively slowly compared to the first bus bar 300. Therefore, the second bus bar 400 can prevent the molten metal on the surface of the first bus bar 300 from expanding and prevent the molten material from scattering on the surface of the first bus bar 300.

[0101] As an example, the second conductive material may include at least one of copper (Cu) and a copper alloy. In this case, the second bus bar 400 may be formed entirely of the second conductive material. Alternatively, the second bus bar 400 may be formed such that only the portion that directly contacts the module bus bar MB is formed of the second conductive material.

[0102] refer to Figure 8 , the sum t3 of the thickness t1 of the first bus bar 300 and the thickness t2 of the second bus bar 400 may be greater than or equal to 1 mm and less than or equal to 3 mm to ensure sufficient weldability between the first bus bar 300 and the cell terminal 232. Here, the thickness t1 of the first bus bar 300 and the thickness t2 of the second bus bar 400 may refer to the thickness parallel to the direction perpendicular to the first surface 301 and the second surface 302, as shown in FIG. Figure 8 As shown in .

[0103] A ratio t2 / t3 of the thickness t2 of the second bus bar 400 to the sum t3 of the thickness t1 of the first bus bar 300 and the thickness t2 of the second bus bar 400 may be greater than or equal to 0.025 and less than or equal to 0.2. When the ratio t2 / t3 of the thickness t2 of the second bus bar 400 to the sum t3 of the thickness t1 of the first bus bar 300 and the thickness t2 of the second bus bar 400 is less than 0.025, there may be a problem that the electrical conductivity of the assembly formed by the first bus bar 300 and the second bus bar 400 becomes too low. When the ratio t2 / t3 of the thickness t2 of the second bus bar 400 to the sum t3 of the thickness t1 of the first bus bar 300 and the thickness t2 of the second bus bar 400 is greater than 0.2, there may be a problem that when laser welding is performed on the first bus bar 300 and the single terminal 232, the bonding strength between the first bus bar 300 and the single terminal 232 is weakened because the molten material of the second bus bar 400 penetrates into the boundary area between the first bus bar 300 and the single terminal 32.

[0104] The thickness t2 of the second bus bar 400 may be greater than or equal to 0.05 mm. That is, even when the sum t3 of the thickness t1 of the first bus bar 300 and the thickness t2 of the second bus bar 400 is less than 2 mm, the thickness t2 of the second bus bar 400 may be greater than or equal to 0.05 mm. When the thickness t2 of the second bus bar 400 is less than 0.05 mm, the contact resistance between the module bus bar MB and the second bus bar 400 may increase excessively, and the surface of the first bus bar 300 may be directly exposed to the outside, causing the module bus bar MB to directly contact the first bus bar 300.

[0105] The battery module 1 according to this embodiment may further include a fixing member 500. The fixing member 500 may fix the module bus bar MB to the second bus bar 400. That is, the fixing member 500 may serve as a component for maintaining a contact state between the module bus bar MB and the second bus bar 400 by applying a fastening force.

[0106] The fixing member 500 may include a first fixing member 510 and a second fixing member 520 .

[0107] The first fixing member 510 may be provided on one side of the second end portion 320 of the first busbar 300, on which the first busbar 300, the second busbar 400, and the module busbar MB are sequentially stacked. The first fixing member 510 may vertically penetrate the first busbar 300, the second busbar 400, and the module busbar MB in the stacking direction of the first busbar 300, the second busbar 400, and the module busbar MB. As an example, the first fixing member 510 may be a bolt having an outer peripheral surface with threads formed thereon and one end portion with a head 511 formed thereon. The other end portion of the first fixing member 510 may vertically penetrate the first busbar 300, the second busbar 400, and the module busbar MB, and protrude outward from the module busbar MB.

[0108] The second fixing member 520 can be connected to the first fixing member 510 and can press the module bus bar MB toward the second bus bar 400. In other words, the second fixing member 520 can serve as a component that, through the pressure generated by tightening with the first fixing member 510, brings the module bus bar MB into close contact with the second bus bar 400. As an example, the second fixing member 520 can be a nut having an inner circumferential surface with threads formed thereon. The second fixing member 520 can be positioned facing the head 511 of the first fixing member 510, with the first bus bar 300, the second bus bar 400, and the module bus bar MB interposed therebetween. The inner circumferential surface of the second fixing member 520 can be threadedly connected to the outer circumferential surface of the other end portion of the first fixing member 510 that protrudes outward from the module bus bar MB. The second fixing member 520 can move toward or away from the head 511 depending on its rotational direction. When the second fixing member 520 moves toward the head 511 by a set distance or more, the module bus bar MB may be securely and tightly fixed to the second bus bar 400 by a fastening pressure acting between the second fixing member 520 and the head 511 .

[0109] Hereinafter, a method of manufacturing a battery module according to one embodiment of the present disclosure will be described.

[0110] Figure 11 is a flowchart schematically illustrating the sequence of a method for manufacturing a battery module according to one embodiment of the present disclosure.

[0111] refer to Figure 11 , the battery cell 200 is placed inside the housing 100 (step S100 ).

[0112] In step S100 , the battery cell 200 may be disposed such that the cell terminal 232 faces the open side of the housing body 110 .

[0113] When the plurality of battery cells 200 are provided in step S100 , the plurality of battery cells 200 may be arranged in at least one row in the longitudinal direction of the housing 100 and in the width direction of the housing 100 inside the housing body 110 .

[0114] After the battery cells 200 are disposed inside the housing 100, each of the plurality of cell bus bars CB may be connected to the cell terminal 232 of the adjacent battery cell 200. Thus, the plurality of battery cells 200 may be electrically connected to each other.

[0115] After step S100 , the first bus bar 300 is brought into contact with the cell terminal 232 of the battery cell 200 (step S200 ).

[0116] Step S200 is performed by a method of seating the first surface 301 of the first bus bar 300 on the cell terminal 232 in a state where the first surface 301 is disposed to face the cell terminal 232 .

[0117] In step S200 , the first bus bar 300 may be brought into contact with the cell terminals 232 of the battery cells 200 in a state in which the second bus bar 400 is integrally stacked on the second surface 302 of the first bus bar 300 .

[0118] In step S200 , the first bus bar 300 may be brought into contact with the cell terminals 232 of the battery cells 200 that are not connected to the cell bus bar CB.

[0119] After step S200 , the cell terminals 232 of the battery cells 200 and the first bus bars 300 are connected to each other (step S300 ).

[0120] Figure 12 is a view schematically illustrating a process of interconnecting a cell terminal and a first bus bar.

[0121] refer to Figure 12 , step S300 may be performed by laser welding which utilizes heat from a laser beam to melt and bond the first bus bar 300 and the cell terminal 232 .

[0122] As an example, in step S300, a laser beam may be irradiated from the second bus bar 400 in a direction toward the first bus bar 300. That is, the laser beam may be irradiated onto the surface of the second bus bar 400 stacked on the second surface 302, which is located on the opposite side of the first surface 301 in contact with the cell terminal 232. In step S300, the laser beam may be irradiated onto the surface of the second bus bar 400 using various types of laser welders.

[0123] Heat generated by the laser beam may be transferred to an interface between the first bus bar 300 and the cell terminal 232 via the second bus bar 400 and the first bus bar 300 .

[0124] At the interface between the first bus bar 300 and the cell terminal 232 , the first bus bar 300 and the cell terminal 232 may be melted, mixed in a liquid state, and then hardened into a solid state, thereby being integrally combined.

[0125] The output of the laser beam irradiated in step S300 may be greater than or equal to 3.4 kW and less than or equal to 4.6 kW. When the output of the laser beam is less than 3.4 kW, heat may not be sufficiently transferred to the boundary area between the first bus bar 300 and the cell terminal 232, and thus the first bus bar 300 and the cell terminal 232 may not be bonded with sufficient strength. When the output of the laser beam is greater than 4.6 kW, pinholes may form, or molten material of the second bus bar 400 may intrude into the boundary area between the first bus bar 300 and the cell terminal 232.

[0126] Figure 13 It is a view illustrating a welding state of the first bus bar and the cell terminal.

[0127] refer to Figure 13 , it can be seen that due to the difference in melting points between the first bus bar 300 and the second bus bar 400, the surface area of ​​the molten metal in the first bus bar 300 can be prevented from excessively increasing, and the occurrence of spattering can be prevented. Furthermore, it can be seen that the molten material B of the second bus bar 400 does not intrude into the boundary region A between the first bus bar 300 and the cell terminal 232. Furthermore, it can be seen that the first bus bar 300 and the cell terminal 232, formed of the same material, are smoothly bonded to each other in the boundary region A between the first bus bar 300 and the cell terminal 232. In this case, the first bus bar 300 and the cell terminal 232 have a welding strength of 2.8 kN.

[0128] After step S300 , the module bus bar MB is brought into contact with the second bus bar 400 (step S400 ).

[0129] Hereinafter, a case where step S400 is performed after step S300 will be described as an example, but the present disclosure is not limited thereto, and step S400 may be performed before step S300 or simultaneously with step S300 .

[0130] Step S400 may be performed by placing the module bus bar MB on the second bus bar 400 stacked on the second end portion 320 of the first bus bar 300 located outside the housing 100 .

[0131] After step S400 , the second bus bar 400 and the module bus bar MB are interconnected (step S500 ). Step S500 may be performed using a fixing member 500 .

[0132] Figure 14 is a view schematically illustrating a process of interconnecting the second bus bar and the module bus bar.

[0133] refer to Figure 14 In step S500 , the first fixing member 510 may be inserted to pass through the first bus bar 300 , the second bus bar 400 , and the module bus bar MB in a stacking direction of the first bus bar 300 , the second bus bar 400 , and the module bus bar MB.

[0134] Thereafter, the second fixing member 520 is fastened to the end portion of the first fixing member 510 protruding outward from the module bus bar MB.

[0135] As an example, the inner circumferential surface of the second fixing member 520 may be screwed to the outer circumferential surface of the first fixing member 510 .

[0136] When the second fixing member 520 rotates in one direction, it can move toward the module bus bar MB. When the second fixing member 520 moves toward the module bus bar MB by more than a set distance, the second fixing member 520 can contact the module bus bar MB and press the module bus bar MB toward the second bus bar 400.

[0137] According to the present disclosure, it is possible to ensure mechanical and electrical connection stability by configuring components providing electrical connection between battery cells inside a battery module and module bus bars outside the battery module using different materials.

[0138] According to the present disclosure, the first bus bar is directly connected to the cell terminal without using any additional components, so that the overall size of the connection structure between the battery cell and the first bus bar can be reduced and spatial freedom in design of the battery module can be ensured.

[0139] According to the present disclosure, the second bus bar is formed to cover the entire surface of the first bus bar and is made of a material having a higher melting point than that of the first bus bar, which can prevent the molten metal area from increasing during the welding process between the first bus bar and the cell terminal and prevent the occurrence of spattering.

[0140] According to the present disclosure, the thickness of the second bus bar satisfies the set range condition, thereby preventing the molten material of the second bus bar from penetrating into the boundary area between the first bus bar and the cell terminal during the welding process of the first bus bar and the cell terminal, thereby further improving the welding quality.

[0141] According to the present disclosure, the thickness of the second bus bar satisfies the set range condition, thereby being able to reduce the contact resistance between the second bus bar and the module bus bar and ensuring stable conductive performance.

[0142] However, the effects obtainable by the present disclosure are not limited to the above effects, and those skilled in the art will clearly understand other technical effects not mentioned from the following description of the present disclosure.

[0143] Although the present disclosure has been described with reference to the embodiments shown in the drawings, these embodiments are merely illustrative, and it is understood that those skilled in the art can derive various modifications and other equivalent embodiments based on the embodiments.

Claims

1. A battery module comprising: shell; a module bus bar, disposed outside the housing; a battery cell, disposed inside the housing; a first bus bar connected to the battery cell and comprising a first conductive material; as well as A second bus bar is connected to the first bus bar and to the module bus bar, the second bus bar including a second conductive material different from the first conductive material. 2 . The battery module according to claim 1 , wherein the melting point of the second conductive material is higher than the melting point of the first conductive material. 3 . The battery module according to claim 1 , wherein the resistivity of the second conductive material is lower than the resistivity of the first conductive material. 4 . The battery module according to claim 1 , wherein the first conductive material comprises at least one of aluminum and an aluminum alloy, and the second conductive material comprises at least one of copper and a copper alloy. 5 . The battery module according to claim 1 , wherein a first side of the first bus bar is disposed inside the housing, and a second side of the first bus bar protrudes to the outside of the housing.

6. The battery module according to claim 1, wherein the first bus bar comprises: a first surface in contact with a cell terminal of the battery cell; as well as a second surface opposite to the first surface, and The second bus bar is stacked on the second surface of the first bus bar. 7 . The battery module according to claim 6 , wherein a sum of a thickness of the first bus bar and a thickness of the second bus bar is greater than or equal to 1 mm and less than or equal to 3 mm. 8 . The battery module according to claim 6 , wherein a ratio of a thickness of the second bus bar to a sum of a thickness of the first bus bar and the thickness of the second bus bar is greater than or equal to 0.025 and less than or equal to 0.

2. 9 . The battery module according to claim 7 , wherein the thickness of the second bus bar is greater than or equal to 0.05 mm. 10 . The battery module according to claim 6 , wherein the first bus bar and the cell terminal are coupled to each other by laser welding.

11. The battery module of claim 6, wherein the cell terminal comprises the first conductive material. 12 . The battery module of claim 6 , wherein the module bus bar is in contact with the second bus bar. 13 . The battery module according to claim 12 , wherein the module bus bar is disposed to face the second surface of the first bus bar, and the second bus bar is located between the module bus bar and the second surface of the first bus bar.

14. The battery module of claim 1 or 12, wherein the module bus bar comprises the second conductive material. 15 . The battery module according to claim 12 , further comprising a fixing member for fixing the module bus bar to the second bus bar.

16. The battery module according to claim 15, wherein the fixing member comprises: a first fixing member passing through the first bus bar, the second bus bar, and the module bus bar; as well as A second fixing member is connected to the first fixing member and is configured to press the module bus bar toward the second bus bar.

17. A method for manufacturing a battery module, the method comprising: The battery cell is arranged inside the housing; contacting a first bus bar with a cell terminal of the battery cell; connecting the cell terminal and the first bus bar; bringing a module bus bar into contact with a second bus bar stacked on the first bus bar; as well as The second bus bar is connected to the module bus bar.

18. The method of claim 17, wherein the cell terminal is connected to the first bus bar using laser welding. 19 . The method according to claim 18 , wherein in the connecting of the cell terminal and the first bus bar, a laser beam is irradiated from the second bus bar in a direction toward the first bus bar. 20 . The method according to claim 19 , wherein an output of the laser beam is greater than or equal to 3.4 kW and less than or equal to 4.6 kW.

Images