Battery module and battery pack including same

Abstract

A battery module according to an embodiment of the present invention includes a battery cell stack in which battery cells having electrode leads protruding in one or both directions are stacked; a busbar frame located on one side of the battery cell stack; a busbar and a sensing member mounted on the busbar frame; and a metal wire connecting the busbar and the sensing member. The busbar includes a first metal layer located on a surface facing the busbar frame and a second metal layer located on a surface opposite to the surface facing the busbar frame. The electrode lead passes through a slit formed in the busbar frame, and is then bent and bonded to the second metal layer. One region of the metal wire is bonded to the first metal layer, and another region of the metal wire is connected to the sensing member.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0107418 filed on August 26, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module and a battery pack including the same, and more particularly to a battery module that can improve manufacturing processability and reduce costs, and a battery pack including the same. [Background technology]

[0003] In modern society, the use of portable devices such as mobile phones, laptops, video cameras, and digital cameras has become commonplace, and technological development in fields related to these mobile devices is accelerating. Furthermore, rechargeable secondary batteries are being used as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), and other vehicles as a way to address air pollution caused by conventional gasoline-powered vehicles that use fossil fuels, and this has led to an increased need for the development of secondary batteries.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Of these, lithium secondary batteries are attracting attention due to their advantages over nickel-based secondary batteries, such as almost no memory effect, freedom in charging and discharging, extremely low self-discharge rate, and high energy density.

[0005] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive and negative electrode active materials, respectively, and include an electrode assembly in which positive and negative electrode plates coated with the positive and negative electrode active materials are arranged with a separator sandwiched therebetween, and a battery case that hermetically houses the electrode assembly together with an electrolyte.

[0006] Generally, lithium secondary batteries can be classified into can-type secondary batteries, in which an electrode assembly is housed in a metal can, and pouch-type secondary batteries, in which an electrode assembly is housed in an aluminum laminate sheet pouch, depending on the shape of the exterior material.

[0007] Secondary batteries used in small devices are configured with two or three battery cells, while secondary batteries used in medium- to large-sized devices such as automobiles use battery modules in which many battery cells are electrically connected. In such battery modules, multiple battery cells are connected in series or parallel to form a stack of battery cells, improving capacity and output. One or more battery modules can be installed with various control and protection systems such as a battery management system (BMS), battery disconnect unit (BDU), and cooling system to form a battery pack.

[0008] Fig. 1 is a partial perspective view showing a conventional battery module. Fig. 2 is an exploded perspective view showing a bus bar, a bus bar frame, and a sensing member included in the battery module of Fig. 1. Fig. 3 is a partial perspective view showing an enlarged view of part "A" in Fig. 2.

[0009] 1 to 3, a conventional battery module 10 includes a battery cell stack 12 containing a plurality of battery cells 11. The battery cell stack 12 is housed inside a module frame, which is not shown for ease of explanation. The plurality of battery cells 11 are stacked in one direction, and a bus bar 50 and a bus bar frame 40 are disposed on one side of the battery cell stack 12 to electrically connect the battery cells 11.

[0010] Specifically, in the battery cell stack 12, the bus bar frame 40 may be positioned in the direction in which the electrode leads 13 of the battery cells 11 are positioned. A bus bar 50 made of a metal material may be attached to the bus bar frame 40. The electrode leads 13 of the battery cells 11 may be welded to the bus bar 50. The electrode leads 13 of the battery cells 11 may be joined to the bus bar 50 and electrically connected to each other in series or parallel.

[0011] The battery module 10 may include a sensing member 60. Voltage information of the battery cells 11 in the battery module 10 may be transmitted to an external battery management system (BMS) via the sensing member 60.

[0012] Specifically, the sensing member 60 includes an FFC (Flat Flexible Cable), a PCB (Printed Circuit Board), or an FPCB (Flexible Printed Circuit Board). A module connector 61 may be connected to the sensing member 60, and a joining member 62 may be connected to one end of the sensing member 60. The plate-shaped joining member 62 may be joined by welding to the bus bar 50 to which the electrode leads 13 are joined. Voltage information of each battery cell 11 can be transmitted to an external battery management system via the bus bar 50, the joining member 62, the sensing member 60, and the module connector 61. The battery management system monitors and controls the status of each battery cell 11 based on this information.

[0013] In this case, in the conventional battery module 10, the joining member 62 and the bus bar 50 are joined by welding. However, in this case, there are problems such as difficulty in automating the manufacturing process, difficulty in reworking the joining, and impossibility of non-destructive testing. Summary of the Invention [Problem to be solved by the invention]

[0014] An object of the present invention is to provide a battery module and a battery pack including the same, which are capable of automating the manufacturing process, reworking the joints, and performing non-destructive testing in the connection between the sensing member and the bus bar.

[0015] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0016] A battery module according to one embodiment of the present invention includes a battery cell stack in which battery cells having electrode leads protruding in one or both directions are stacked; a busbar frame located on one side of the battery cell stack; a busbar and a sensing member attached to the busbar frame; and a metal wire connecting the busbar and the sensing member. The busbar includes a first metal layer located on a surface facing the busbar frame and a second metal layer located on a surface opposite the surface facing the busbar frame. The electrode lead passes through a slit formed in the busbar frame, is bent, and is bonded to the second metal layer. One region of the metal wire is bonded to the first metal layer, and another region of the metal wire is connected to the sensing member.

[0017] The metal wire and the bus bar may be bonded together by wire bonding. The sensing member may include a flat flexible cable (FFC), a printed circuit board (PCB), or a flexible printed circuit board (FPCB).

[0018] The first metal layer may include an aluminum material, and the second metal layer may include a copper material.

[0019] The metal wire may include an aluminum material.

[0020] A bent portion may be formed on one side of the bus bar, and the first metal layer may be exposed at the bent portion on a surface opposite to a surface facing the bus bar frame.

[0021] The metal wire may be bonded to a portion of the first metal layer exposed by the bent portion.

[0022] A through hole may be formed in the second metal layer, and the first metal layer may be exposed through the through hole to a surface opposite to a surface facing the bus bar frame.

[0023] The metal wire can be bonded to the portion of the first metal layer exposed through the through hole.

[0024] The bus bar may be plate-shaped, and the first metal layer may have a thickness of 85% to 90% of the thickness of the bus bar, and the second metal layer may have a thickness of 10% to 15% of the thickness of the bus bar.

[0025] The battery cells may be pouch-type battery cells, and the battery cells may be stacked upright to form the battery cell stack.

[0026] A battery pack according to an embodiment of the present invention includes the battery module. [Effects of the Invention]

[0027] According to an embodiment of the present invention, a joining method using a metal wire is applied to connect the sensing member and the bus bar, which makes it possible to automate the manufacturing process, perform rework of the joining, and perform non-destructive testing.

[0028] In addition, the busbars contain both copper and aluminum materials, which reduces material costs.

[0029] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 10 is a partial perspective view showing a conventional battery module. [Figure 2] 2 is an exploded perspective view showing a bus bar, a bus bar frame, and a sensing member included in the battery module of FIG. 1. FIG. [Figure 3] FIG. 3 is a partial perspective view showing an enlarged view of part "A" in FIG. 2. [Figure 4] 1 is an exploded perspective view showing a battery module according to an embodiment of the present invention; [Figure 5] 5 is a diagram showing one of the battery cells included in the battery module of FIG. 4. [Figure 6] 5 is a perspective view showing a bus bar frame, a bus bar, a sensing member, and the like included in the battery module of FIG. 4. FIG. [Figure 7] FIG. 7 is an exploded perspective view showing the bus bar frame, the bus bar, the sensing member, and the like shown in FIG. 6. [Figure 8] 1 is a view showing a bus bar according to an embodiment of the present invention. [Figure 9] FIG. 7 is a partial perspective view showing an enlarged view of part "B" in FIG. 6. [Figure 10] 10 is an enlarged partial view showing the connection between the bus bar and the metal wire in FIG. 9. [Figure 11] 10 is a perspective view showing a bus bar frame, a bus bar, a sensing member, etc. according to another embodiment of the present invention. FIG. [Figure 12] 12 is a diagram showing the bus bar of FIG. 11. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement various embodiments of the present invention. The present invention can be embodied in several different forms and is not limited to the examples described herein.

[0032] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0033] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are exaggerated to clearly show multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0034] Furthermore, when a layer, film, region, plate, or other part is said to be "on" or "above" another part, this includes not only the case where it is "directly above" that other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in the middle. Furthermore, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" or "above" the direction opposite to gravity.

[0035] Furthermore, throughout the specification, when a part "comprises" a certain element, it does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0036] Also, throughout the specification, "on a plane" means when the target part is viewed from above, and "on a cross section" means when the target part is cut vertically and viewed from the side.

[0037] 4 is an exploded perspective view of a battery module according to an embodiment of the present invention, and FIG 5 is a view showing one of the battery cells included in the battery module of FIG 4.

[0038] 4 and 5, a battery module 100 according to an embodiment of the present invention includes a battery cell stack 120 in which battery cells 110 are stacked, and a bus bar frame 400 located on one side of the battery cell stack 120.

[0039] First, the battery cell 110 is preferably a pouch-type battery cell and may be formed in a rectangular sheet-type structure. The battery cell 110 according to this embodiment has electrode leads 111 protruding in one or both directions. As an example, FIG. 5 shows a structure in which two electrode leads 111 face each other and protrude from one end 114a and the other end 114b of the cell body 113, respectively. More specifically, the electrode leads 111 are connected to an electrode assembly (not shown) and protrude from the electrode assembly (not shown) to the outside of the battery cell 110. Although not specifically shown, a battery cell in which two electrode leads 111 protrude in the same direction is also possible as an embodiment of the present invention.

[0040] Meanwhile, the battery cell 110 can be manufactured by bonding both ends 114a, 114b of the cell case 114 and one side 114c connecting them together while an electrode assembly (not shown) is housed in the cell case 114. That is, the battery cell 110 according to this embodiment has a total of three sealing portions 114sa, 114sb, and 114sc, and the sealing portions 114sa, 114sb, and 114sc are sealed by a method such as heat fusion, and the remaining one side may be formed as a folding portion 115. The folding portion 115 may form a structure in which the cell case 114 is folded. The cell case 114 may be formed as a laminate sheet including a resin layer and a metal layer.

[0041] Furthermore, the folding portion 115 may extend lengthwise along one edge of the battery cell 110, and a protrusion 110p of the battery cell 110, called a bat ear, may be formed at the end of the folding portion 115. However, the protrusion 110p is only an exemplary structure, and in another embodiment of the present invention, another battery cell 110 may have a shape in which the folding portion 115 extends in a straight line without being formed with a protrusion.

[0042] In addition, the cell case 114 is sealed with the protruding electrode leads 111 therebetween, and a terrace portion 116 may be formed between the electrode leads 111 and the cell body 113. That is, the battery cell 110 includes the terrace portion 116 formed by extending from the cell body 113 in the direction in which the electrode leads 111 protrude.

[0043] A plurality of battery cells 110 are stacked so as to be electrically connected to each other to form a battery cell stack 120. In particular, as shown in FIG. 4 , a plurality of battery cells 110 can be stacked upright along a direction parallel to the y-axis, with one surface of each cell body 113 facing each other. This allows the electrode leads 111 to protrude in a direction perpendicular to the direction in which the battery cells 110 are stacked. That is, in a battery cell 110, one electrode lead 111 can protrude in the x-axis direction, and the other electrode lead 111 can protrude in the negative x-axis direction. In the event that a battery cell has an electrode lead 111 protruding in only one direction, the electrode lead 111 protrudes in either the x-axis direction or the negative x-axis direction.

[0044] Meanwhile, the battery module 100 according to this embodiment may include a module frame 200 and end plates 300 that form an internal space in which the battery cell stack 120 is housed.

[0045] The module frame 200 may be a structure having one side and the other side opposite the one side open. More specifically, the module frame 200 may be open in both directions, relative to the battery cell stack 120, where the electrode leads 111 protrude. In one embodiment of the present invention, the module frame 200 may be a monoframe having an integrated top, bottom, and both sides. In another embodiment of the present invention, the module frame 200 may include a U-shaped frame covering the bottom and both sides of the battery cell stack 120, and an upper cover covering the top of the battery cell stack 120. The U-shaped frame and the upper cover may be joined at corresponding corners to form the module frame 200. There are no particular limitations on the joining method, and welding may be used, for example.

[0046] A plurality of end plates 300 may be provided, each covering the open one side and the other side of the module frame 200. The battery cell stack 120 is housed in an internal space formed by the module frame 200 and the end plates 300, thereby physically protecting the battery cell stack 120. To this end, the module frame 200 and the end plates 300 may include a metal material having a predetermined strength. Meanwhile, the module frame 200 and the end plates 300 may be joined by welding or other methods with corresponding corners in contact with each other.

[0047] The bus bar frame, bus bar, and sensing member according to this embodiment will be described in detail below.

[0048] Fig. 6 is a perspective view showing the bus bar frame, bus bars, sensing members, etc. included in the battery module of Fig. 4. Fig. 7 is an exploded perspective view showing the bus bar frame, bus bars, sensing members, etc. of Fig. 6.

[0049] 4 to 7, the bus bar frame 400 according to this embodiment is located on one side of the battery cell stack 120. Specifically, the bus bar frame 400 may be located on one side of the battery cell stack 120 in the direction in which the electrode leads 111 protrude. Although FIG. 4 shows only one bus bar frame 400 located on one side of the battery cell stack 120, another bus bar frame may be additionally located on the opposite side of the battery cell stack 120. In other words, a total of two bus bar frames 400 may be located on both sides of the battery cell stack 120.

[0050] The battery module 100 according to this embodiment includes a bus bar 500 mounted on a bus bar frame 400 and a sensing member 600. The battery module 100 also includes a metal wire 700 connecting the bus bar 500 and the sensing member 600.

[0051] The bus bar 500 is used to electrically connect the battery cells 110 inside the battery module 100 and preferably includes a metal material to enable electrical connection. The bus bar 500 may be attached to the side of the bus bar frame 400 opposite the side facing the battery cell stack 120. The electrode leads 111 protruding from the battery cells 110 may pass through slits 400S formed in the bus bar frame 400 and then bend to connect to the bus bar 500. More specifically, one electrode lead 111 may pass through the slit 400S of the bus bar frame 400 located on one side of the battery cell stack 120 and then bend to connect to the bus bar 500, while the other electrode lead 111 may pass through a slit in a bus bar frame (not shown) located on the other side of the battery cell stack 120 and then connect to the bus bar 500. There are no particular limitations on the method of connection between the electrode leads 111 and the bus bar 500, but welding may be used as an example. The connection between the electrode leads 111 and the bus bar 500 will be described again with reference to FIG. 9.

[0052] As described above, the electrode leads 111 of the battery cells 110 are connected to the bus bars 500, thereby realizing electrical series or parallel connection between the battery cells 110.

[0053] Meanwhile, the bus bar frame 400 preferably includes an electrically insulating material to prevent short circuits from occurring due to contact between the bus bar 500 or other electrical components and parts of the battery cell 110 other than the electrode leads 111. As an example, the bus bar frame 400 may be made of plastic injection molding.

[0054] Meanwhile, in addition to the busbar 500, a terminal busbar 500T may be attached to the busbar frame 400. Like the busbar 500, the terminal busbar 500T may be attached to the surface of the busbar frame 400 opposite the surface facing the battery cell stack 120, and the electrode leads 111 may pass through slits 400S formed in the busbar frame 400 and then be bent to connect to the terminal busbar 500T. The terminal busbar 500T is generally similar to the busbar 500, but unlike the busbar 500, has a portion exposed to the outside. For example, a terminal opening hole 300H (see FIG. 4) may be formed in the end plate 300, and an upwardly extending portion of the terminal busbar 500T may pass through the terminal opening hole 300H and be exposed to the outside of the battery module 100.

[0055] The terminal bus bar 500T functions as an input / output terminal of the battery module 100 for HV (High Voltage) connection. HV connection refers to an electrical connection that requires a relatively high voltage, such as the input / output terminals of a battery module. The battery module 100 according to this embodiment can be connected to other battery modules or a battery disconnection unit (BDU) that controls the electrical connection of battery modules through the exposed portion of the terminal bus bar 500.

[0056] The sensing member 600 is a member for LV (Low Voltage) connection of the battery module 100. LV connection refers to an electrical connection that requires a relatively low voltage, such as in battery electrical components. For example, the sensing member 600 senses voltage data and temperature data of the battery cells 110 included in the battery module 100 and transmits the sensed voltage and temperature data to a Battery Management System (BMS) located outside the battery module 100. The battery management system manages the voltage and temperature of the battery module 100 based on the transmitted voltage and temperature data.

[0057] To sense the voltage data of the battery cells 110, the sensing member 600 may be electrically connected to the bus bar 500 to which the electrode leads 111 are bonded via a metal wire 700 (described below). Similar to the bus bar 500, the sensing member 600 may be attached to the surface of the bus bar frame 400 opposite to the surface facing the battery cell stack 120, or may be attached to an upper region of the bus bar frame 400. The sensing member 600 may include a flat flexible cable (FFC), a printed circuit board (PCB), or a flexible printed circuit board (FPCB).

[0058] A module connector 610 may be connected to the sensing member 600. The module connector 610 is a member exposed to the outside of the battery module 100 and is connected to a battery management system (BMS) located outside the battery module 100, and may transmit voltage and temperature data measured by the sensing member 600 to the battery management system.

[0059] As described above, the electrode lead 111 is joined to the bus bar 500, and the metal wire 700 connects the bus bar 500 to the sensing member 600. Specifically, one region of the metal wire 700 is joined to the bus bar 500, and another region of the metal wire 700 is connected to the sensing member 600.

[0060] In this case, the metal wire 700 and the bus bar 500 may be bonded by wire bonding. Wire bonding is a bonding method mainly used in semiconductor manufacturing processes, and refers to a method of connecting an integrated circuit and a terminal with a thin metal wire. That is, wire bonding refers to a technology of making an electrical interconnection using a metal wire by combining ultrasonic energy and pressure.

[0061] On the other hand, there are no particular limitations on the method of connecting the metal wire 700 and the sensing member 600 as long as an electrical connection between them is possible.

[0062] As shown in Figures 2 and 3, in a conventional battery module 10, a joining member 62, which is a plate-shaped metal member, is welded to the bus bar 50 when connecting the sensing member 600 and the bus bar 50. In particular, resistance welding, ultrasonic welding, or laser welding is used. On the other hand, in the battery module 100 according to the present embodiment, wire bonding using a metal wire 700 is used when connecting the sensing member 600 and the bus bar 500. Below, advantages of the battery module 100 of the present invention compared to the conventional battery module 10 will be described from the perspectives of automation of the manufacturing process, rework of joining, and non-destructive testing.

[0063] First, in the conventional process of joining the joining member 62 and the bus bar 50 of the battery module 10, the strength of the welded joint can be ensured even when there is no gap between the joining member 62 and the bus bar 50. To eliminate the gap, a clamping operation is performed on the sensing member 60 first, but due to the flexible characteristics of the sensing member 60, it is difficult to fix the sensing member 60 during the clamping operation. Therefore, the clamping operation is difficult to automate and must be performed manually. On the other hand, when using the metal wire 700 as in this embodiment, two connection objects can be joined even if they have different lengths, directions, or heights, thereby solving the gap problem that existed in the conventional method and enabling automation of the manufacturing process.

[0064] Second, when a welding process such as laser welding is applied between the joining member 62 and the bus bar 50, chemical transformation occurs between the two metal materials. Therefore, if rework is required, welding must be performed on the remaining unwelded area of the joining member 62, but this area is not large, making rework difficult. On the other hand, wire bonding using the metal wire 700 makes rework easy because no chemical reaction occurs on the surface of the metal material. Another advantage of wire bonding is that rework is possible as long as only a very small area is secured.

[0065] Finally, when a welded joint such as laser welding is applied between the joining member 62 and the bus bar 50, the strength of the weld must be evaluated through destructive testing. On the other hand, in the case of wire bonding using the metal wire 700, the joining strength can be evaluated non-destructively by applying a predetermined force to the metal wire 700 at the same time as the wire bonding is performed. Strength evaluation can be performed even when only a force smaller than the strength at which the metal wire 700 breaks is applied to the metal wire 700. This non-destructive testing enables 100% monitoring of the joining in real time during the process.

[0066] A specific embodiment of the bus bar according to this embodiment will be described in detail below.

[0067] Figure 8 is a view showing a bus bar according to an embodiment of the present invention. Figure 9 is a partial perspective view showing an enlarged view of part "B" in Figure 6. Figure 10 is a partial view showing an enlarged view of the connection between the bus bar and the metal wire in Figure 9. For ease of explanation, however, Figure 9 shows the electrode lead 111 bent after passing through the slit 400S of the bus bar frame 400.

[0068] 8 to 10 together with FIGS. 4 and 6, a bus bar 500 according to this embodiment includes a first metal layer 510 disposed on a surface facing the bus bar frame 400 and a second metal layer 520 disposed on a surface opposite the surface facing the bus bar frame 400. In FIG. 8, the second metal layer 520 is indicated by shading for ease of distinction.

[0069] The electrode leads 111 of the battery cells 110 pass through slits 400S formed in the bus bar frame 400, and are then bent and bonded to the second metal layer 520. The metal wires 700 are bonded to the first metal layer 510. That is, one region of the metal wires 700 is bonded to the first metal layer 510, and the other region of the metal wires 700 is connected to the sensing member 600.

[0070] The first metal layer 510 may include an aluminum material, and the second metal layer 520 may include a copper material. Specifically, the bus bar 500 according to this embodiment may be a clad member in which the first metal layer 510 and the second metal layer 520 are bonded together by rolling. For example, the first metal layer 510 includes an aluminum material, and the second metal layer 520 includes a copper material. In other words, the first and second metal layers 510 and 520, which are made of different materials, are bonded together by rolling to form the bus bar 500 according to this embodiment. Here, clad bonding for manufacturing a clad member refers to a technique in which a metal or non-metal is used as a base layer and another metal is bonded to one side of the base layer by rolling. This is a bonding technique in which the characteristics of each material are simultaneously exhibited. That is, the bus bar 500 according to this embodiment may be formed by bonding the first metal layer 510 and the second metal layer 520 using a clad bonding technique. The bus bar 500 is attached to the bus bar frame 400 such that the first metal layer 510 faces the bus bar frame 400 and the second metal layer 520 does not face the bus bar frame 400 .

[0071] The second metal layer 520 is a region to which the electrode leads 111 passing through the slits 400S are bent and then joined. As the capacity of battery cells gradually increases and the charging time shortens, controlling heat generation from battery cells is an important issue. Copper has excellent thermal and electrical conductivity, and when applied to the bus bar 500, it has excellent heat dissipation properties, can improve the cooling performance of the battery module 100, and can reduce the resistance of the electrical connection with the electrode leads 111. That is, to improve the heat dissipation properties and reduce the resistance of the bus bar 500, the second metal layer 520 of the bus bar 500 can contain a copper material.

[0072] Meanwhile, conventional busbars 50 can be formed of a single layer of copper material. However, copper has excellent thermal and electrical conductivity, but is disadvantageous in that it is somewhat expensive. In contrast, in this embodiment, busbar 500 is not formed of a single layer of copper material, but is formed to include first metal layer 510 and second metal layer 520. The aluminum material included in first metal layer 510 is about three to four times cheaper than the copper material included in second metal layer 520, thereby reducing material costs. Overall, to simultaneously achieve improved cooling performance, reduced resistance, and cost reduction, busbar 500 according to this embodiment is designed to include first metal layer 510 including aluminum material and second metal layer 520 including copper material.

[0073] In this case, in the plate-shaped bus bar 500, the first metal layer 510 containing an aluminum material may have a thickness of 85% to 90% of the thickness of the bus bar 500, and the second metal layer 520 containing a copper material may have a thickness of 10% to 15% of the thickness of the bus bar 500.

[0074] If the thickness of the first metal layer 510 is less than 85% and the thickness of the second metal layer 520 is more than 15% of the thickness of the bus bar 500, the manufacturing cost of the bus bar 500 may be excessively high compared to the desired degree of heat dissipation of the bus bar 500.

[0075] Furthermore, if the thickness of the first metal layer 510 is more than 90% and the thickness of the second metal layer 520 is less than 10% of the thickness of the bus bar 500, the heat dissipation of the bus bar 500 may be insufficient, and the battery module 100 may not meet the cooling performance standards.

[0076] Meanwhile, the metal wire 700 according to this embodiment may include an aluminum material. That is, the metal wire 700 may include the same material as the material of the first metal layer 510 to which the metal wire 700 is bonded. Aluminum is widely used in processes for manufacturing battery modules and has the advantage of being inexpensive. Therefore, aluminum may be used as the material of the metal wire 700 for wire bonding.

[0077] In wire bonding between metal wire 700 and bus bar 500, bonding performance improves when the same materials are bonded together, so the metal wire 700 containing aluminum material is designed to be bonded to the first metal layer 510 containing aluminum material.

[0078] However, because the second metal layer 520 must be bonded to the electrode lead 111, the second metal layer 520 is located on the surface opposite to the surface facing the bus bar frame 400. The first metal layer 510 is located on the surface facing the bus bar frame 400, but in this case, due to positional restrictions, it may be difficult to bond the first metal layer 510 and the metal wire 700.

[0079] In contrast, in this embodiment, a bending portion 500B is formed on one side of the bus bar 500. In this bending portion 500B, the first metal layer 510 may be exposed on the surface opposite to the surface facing the bus bar frame 400. The bending portion 500B may be a portion where both the first metal layer 510 and the second metal layer 520 of the bus bar 500 are bent and extended.

[0080] 9 and 10, the metal wire 700 may be bonded to a portion of the first metal layer 510 that is exposed by the bending portion 500B. In this embodiment, the first metal layer 510 is included in the bus bar 500 to reduce material costs, and the bending portion 500B is formed to allow the metal wire 700 to be easily bonded to the first metal layer 510, thereby ensuring ease of manufacturing.

[0081] Although there is no particular limitation on the position of the bending portion 500B, it is preferable that the bending portion 500B be located close to the sensing member 600. As an example, the bending portion 500B may be formed on the upper portion of the bus bar 500. Also, as shown in Figures 6 and 7, the bending portion 500B may be formed not only on the bus bar 500 but also on the terminal bus bar 500T, and the metal wire 700 may be joined to the first metal layer 510 of the bending portion 500B of the terminal bus bar 500T.

[0082] A bus bar according to another embodiment of the present invention will now be described, with the overlapping parts of the description already given being omitted.

[0083] Figure 11 is a perspective view showing a bus bar frame, a bus bar, and a sensing member according to another embodiment of the present invention. Figure 12 is a diagram showing the bus bar of Figure 11. In Figure 12, the second metal layer 520 is shown in shading for ease of distinction.

[0084] 11 and 12, according to another embodiment of the present invention, a bus bar 500 and a sensing member 600 may be attached to a bus bar frame 400. The bus bar 500 and the sensing member 600 may be connected by a metal wire 700. A terminal bus bar 500T may be attached to the bus bar frame 400, and the sensing member 600 may be connected to a module connector 610.

[0085] The bus bar 500 also includes a first metal layer 510 located on a surface facing the bus bar frame 400 and a second metal layer 520 located on a surface opposite to the surface facing the bus bar frame 400. The electrode leads 111 of the battery cells 110 pass through slits formed in the bus bar frame 400, are bent, and then joined to the second metal layer 520. Up to this point, the structure is similar to that of the bus bar previously described with reference to Figures 8 to 10. However, bus bar 500 according to this embodiment differs in that through holes 520H are formed in second metal layer 520 instead of bending portions.

[0086] Specifically, through holes 520H are formed in the second metal layer 520, and the first metal layer 510 can be exposed through the through holes 520H on a surface opposite to the surface facing the bus bar frame 400. The metal wire 700 can be bonded to the portion of the first metal layer 510 exposed through the through holes 520H. In this embodiment, the first metal layer 510 is included in the bus bar 500 to reduce material costs, and the through holes 520H are formed in the second metal layer 520 to easily bond the metal wire 700 to the first metal layer 510, thereby ensuring ease of manufacturing.

[0087] Although there is no particular limitation on the position of the through hole 520H, it is preferable that the through hole 520H be located close to the sensing member 600. As an example, the through hole 520H may be formed in an upper region of the bus bar 500. Furthermore, as shown in Fig. 11, the through hole 520H may be formed not only in the bus bar 500 but also in the terminal bus bar 500T, and the metal wire 700 may be bonded to the first metal layer 510 exposed through the through hole 520H of the terminal bus bar 500T.

[0088] In this embodiment, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are used for convenience of explanation and may differ depending on the position of the object of interest or the position of the observer.

[0089] One or more battery modules according to the above-described embodiments may be mounted together with various control and protection systems such as a battery management system (BMS), a battery disconnect unit (BDU), and a cooling system to form a battery pack.

[0090] The battery module or battery pack can be applied to various devices, specifically, but not limited to, transportation means such as electric bicycles, electric vehicles, and hybrids, and ESS (Energy Storage Systems), and can be applied to various devices that can use secondary batteries. Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0091] 100 battery modules 110 battery cells 120 Battery cell stack 400 busbar frame 500 busbar 500B bending section 510 1st metal layer 520 2nd metal layer 520H through hole 600 Sensing material 700 Metal Wire

Claims

1. a battery cell stack in which battery cells having electrode leads protruding in one or both directions are stacked; a bus bar frame located on one side of the battery cell stack; a bus bar and a sensing member attached to the bus bar frame; and a metal wire connecting the bus bar and the sensing member; the bus bar includes a first metal layer disposed on a surface facing the bus bar frame and a second metal layer disposed on a surface opposite to the surface facing the bus bar frame, the electrode leads are passed through slits formed in the bus bar frame, and then bent and joined to the second metal layer; A region of the metal wire is bonded to the first metal layer, and another region of the metal wire is connected to the sensing member.

2. The battery module according to claim 1 , wherein the metal wire and the bus bar are joined by wire bonding.

3. The battery module according to claim 1 , wherein the sensing member comprises a flat flexible cable (FFC), a printed circuit board (PCB), or a flexible printed circuit board (FPCB).

4. The battery module of claim 1 , wherein the first metal layer comprises an aluminum material and the second metal layer comprises a copper material.

5. The battery module according to claim 4 , wherein the metal wires include an aluminum material.

6. A bent portion is formed on one side of the bus bar, The battery module of claim 1 , wherein the first metal layer is exposed at the bent portion on a surface opposite to a surface facing the bus bar frame.

7. The battery module of claim 6 , wherein the metal wire is bonded to a portion of the first metal layer exposed by the bent portion.

8. The battery module of claim 1 , wherein a through hole is formed in the second metal layer, and the first metal layer is exposed through the through hole on a surface opposite to a surface facing the bus bar frame.

9. The battery module of claim 8 , wherein the metal wire is bonded to a portion of the first metal layer exposed through the through hole.

10. the bus bar is plate-shaped, the first metal layer has a thickness of 85% to 90% of the thickness of the bus bar, The battery module of claim 1 , wherein the second metal layer has a thickness that is 10% to 15% of the thickness of the bus bar.

11. the battery cell is a pouch-type battery cell, The battery module of claim 1 , wherein the battery cells are stacked upright to form the battery cell stack.

12. A battery pack comprising the battery module according to any one of claims 1 to 11.

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