KR20240097773A - Battery cell and battery module including the same - Google Patents

Abstract

A battery cell according to an embodiment of the present invention includes an electrode assembly including electrodes and a separator positioned between the electrodes; and a pouch case in which the electrode assembly is stored and its outer periphery is sealed. The electrode includes an electrode current collector and an active material layer formed on one or both sides of the electrode current collector, and the electrode current collector has a protrusion formed by a portion of the electrode current collector protruding to the outside of the sealed pouch case. It includes a bus bar connected to the protrusion.

Description

Battery cell and battery module including the same {BATTERY CELL AND BATTERY MODULE INCLUDING THE SAME}

The present invention relates to a battery cell and a battery module containing the same, and more specifically, to a pouch-type battery cell and a battery module containing the same.

In modern society, as the use of portable devices such as mobile phones, laptops, camcorders, and digital cameras becomes routine, the development of technologies in fields related to the above mobile devices is becoming more active. In addition, secondary batteries that can be charged and discharged are a way to solve air pollution from existing gasoline vehicles that use fossil fuels, and are used in electric vehicles (EV), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicles ( As it is used as a power source for batteries such as P-HEV), the need for development of secondary batteries is increasing.

In general, lithium secondary batteries can be classified into can-type secondary batteries in which the electrode assembly is built into a metal can and pouch-type secondary batteries in which the electrode assembly is built in a pouch of an aluminum laminate sheet, depending on the shape of the exterior material.

In the case of secondary batteries used in small devices, 2-3 battery cells are placed, but in the case of secondary batteries used in medium to large devices such as automobiles, a battery module is made by electrically connecting multiple battery cells. This is used. These battery modules have improved capacity and output by connecting multiple battery cells in series or parallel to form a battery cell stack. Additionally, one or more battery modules may be mounted together with various control and protection systems such as a Battery Disconnect Unit (BDU), Battery Management System (BMS), and cooling system to form a battery pack.

In a conventional battery module, a busbar and a busbar frame can be used to electrically connect multiple battery cells. Below, with reference to FIGS. 1 and 2, the structure of the busbar and busbar frame used in a conventional battery module will be described.

Figure 1 is a perspective view showing a conventional battery module. FIG. 2 is a partial view showing an enlarged portion of “A” in FIG. 1. In particular, Figure 1 shows the battery module standing up to show the bus bar frame and bus bar. Figure 3 is a cross-sectional view for explaining the connection form between the electrode tab inside the battery cell and the electrode lead in a conventional battery module.

Referring to Figures 1 to 3, the conventional battery module 10 includes a battery cell stack 12 in which a plurality of battery cells 11 are stacked and a bus disposed on both sides of the battery cell stack 12. Includes a bar frame (30). A bus bar 40 may be mounted on this bus bar frame 30.

The bus bar 40 is for electrical connection between a plurality of battery cells 11, and the electrode lead 11L of the battery cell 11 passes through a slit formed in the bus bar frame 30 and is bent to form the bus bar 40. ) can be connected to. In some cases, the electrode lead 11L may pass through the slit 40S formed in the bus bar 40.

Regarding the connection between the electrode lead 11L and the bus bar 40, there is no limitation to the method as long as electrical connection is possible, and for example, the connection may be made by welding joint. The battery cells 11 may be electrically connected in series or parallel via the bus bar 40.

The battery cell 11 can be manufactured by storing the electrode assembly 11A inside a pouch-shaped cell case 11C and then sealing the outer periphery of the cell case 11C to form a sealing portion 11S. there is. The electrode assembly 11A may include electrodes and a separator disposed between the electrodes. Each electrode includes an electrode tab 11t, and the electrode tabs 11t may be connected to the electrode lead 11L by a method such as welding. More specifically, the electrode includes an electrode current collector made of a metal material and an electrode active material layer formed by applying an electrode active material to one or both sides of the electrode current collector. A portion of this electrode current collector may be extended to form an electrode tab 11t. When forming the sealing portion 11S by sealing the outer periphery of the cell case 11C, the lead film 11F surrounding the electrode lead 11L is placed between the sealing portions 11S to improve sealing properties and secure electrical insulation. may be involved.

The electrode lead 11L protrudes to the outside of the cell case 11C, passes through the slit 30S of the bus bar frame 30 and the slit 40S of the bus bar 40, and is bent to the bus bar ( 40).

In the case of the conventional battery cell 11, after pre-welding the electrode tabs 11t, the electrode tabs 11t are welded to the electrode lead 11L, and the electrode lead 11L is connected to the bus bar. Weld at (40). Welding resistance between the electrode tabs 11t, welding resistance between the electrode tab 11t and the electrode lead 11L, and welding resistance between the electrode lead 11L and the bus bar 40, that is, a total of three welding resistances. This can happen.

The resistance of the battery cell 11 is a factor that affects not only the heat generation of the battery cell 11 but also the voltage measurement, and whether the correct voltage is measured to guarantee the output range in battery modules that recently require high output is determined by the battery. This is a major management target along with the heat generation of the cell 11. Therefore, there is a need to develop technology that can reduce internal resistance in the structure of battery cells and battery modules containing them.

The problem to be solved by the present invention is to provide a battery cell that can reduce internal resistance and a battery module including the same.

However, the problems to be solved by the embodiments of the present invention are not limited to the above-described problems and can be expanded in various ways within the scope of the technical idea included in the present invention.

A battery cell according to an embodiment of the present invention includes an electrode assembly including electrodes and a separator positioned between the electrodes; and a pouch case in which the electrode assembly is stored and its outer periphery is sealed. The electrode includes an electrode current collector and an active material layer formed on one or both sides of the electrode current collector, and the electrode current collector has a protrusion formed by a portion of the electrode current collector protruding to the outside of the sealed pouch case. It includes a bus bar connected to the protrusion.

The protrusion and the bus bar may be joined by welding.

With the protrusion joined to the bus bar, the outer periphery of the pouch case may be sealed.

The outer periphery of the pouch case may be sealed to form a sealing portion, and a film surrounding the protrusion may be interposed between the sealing portions.

The film may cover the portion of the protrusion exposed to the outside of the sealing portion.

The film may cover a portion where the protrusion is joined to the bus bar and at least a partial area of the bus bar.

The battery module according to an embodiment of the present invention includes a battery cell stack in which the battery cells are stacked, and the bus bars are connected to each other through a mechanical fastening method, so that electrical connection is made between the battery cells.

The mechanical fastening method may be bolt fastening, riveting fastening, clinching fastening, or fitting fastening.

In the battery cell stack, the battery cells may be stacked along one direction so that one side faces each other.

The battery module may include a connection bus bar connecting the bus bars.

The connecting bus bar may be connected to at least two of the bus bars through a mechanical fastening method.

A through hole may be formed in each of the bus bar and the connection bus bar, and a bolt member may be fastened to a nut member after passing through the through hole of the bus bar and the through hole of the connection bus bar.

A through hole may be formed in each of the bus bar and the connecting bus bar, and a rivet member may fasten the through hole of the bus bar and the through hole of the connecting bus bar.

The bus bar and the connecting bus bar may be connected to each other by a clinching fastening method.

An insertion groove may be formed in one of the connection bus bars for the bus bar, and the other one of the bus bar and the connection bus bar may be inserted into the insertion groove, and the bus bar and the connection bus bar may be connected to each other.

The connection bus bar may be a bar-shaped metal member or a metal member with a bending portion.

The protrusions of at least two of the battery cells may be connected to one of the bus bars.

At least one bus bar frame may be disposed on one or both sides of the battery cell stack, and the bus bar frame may be located between the bus bar and the battery cell stack.

According to embodiments of the present invention, resistance in the process of electrical connection of battery cells can be reduced through a battery cell-busbar integrated structure in which the electrode current collector within the electrode is directly bonded to the bus bar. Accordingly, voltage measurement errors in high-output battery modules can be reduced, and heat generation from battery cells during charging and discharging can be reduced.

Meanwhile, by applying a mechanical fastening structure to the connection between bus bars in the battery module, the degree of freedom in design is increased. In addition, the mechanical fastening structure is easier to rework than welding, and there is no need to worry about loss due to poor welding.

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

Figure 1 is a perspective view showing a conventional battery module.
FIG. 2 is a partial view showing an enlarged portion of “A” in FIG. 1.
Figure 3 is a cross-sectional view for explaining the connection form between the electrode tab inside the battery cell and the electrode lead in a conventional battery module.
Figure 4 is an exploded perspective view showing a battery module according to an embodiment of the present invention.
Figure 5 is a plan view showing one of the battery cells included in the battery module of Figure 4.
Figure 6 is a cross-sectional view taken along the cutting line B-B' of Figure 5.
Figure 7 is a partial perspective view showing an enlarged portion of the battery cell stack and bus bar included in the battery module of Figure 4.
Figure 8 is a partial perspective view for explaining the bolt fastening structure between a bus bar and a connecting bus bar according to an embodiment of the present invention.
Figure 9 is a perspective view showing a bus bar frame according to an embodiment of the present invention.
Figure 10 is a front view showing a bus bar frame according to another embodiment of the present invention.
Figure 11 is a front view schematically showing a bus bar, a connecting bus bar, and a bus bar frame according to an embodiment of the present invention.
12 and 13 are cross-sectional views of battery cells according to different embodiments of the present invention, respectively.
Figures 14 and 15 are perspective views showing a rivet fastening method among mechanical fastening methods according to embodiments of the present invention.
FIG. 16 is a cross-sectional view taken along the cutting line C-C' of FIG. 15.
Figure 17 is a perspective view showing the clinching fastening method among the mechanical fastening methods according to embodiments of the present invention.
Figure 18 is a cross-sectional view taken along the cutting line DD' of Figure 17.
Figures 19 (a) and (b) are cross-sectional views illustrating a fitting coupling among the mechanical fastening methods according to embodiments of the present invention.
Figure 20 is a partial perspective view showing an enlarged portion of the battery cell stack and bus bar according to another embodiment of the present invention.

Hereinafter, with reference to the attached drawings, various embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The invention may be implemented in many different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts that are not relevant to the description are omitted, and identical or similar components are assigned the same reference numerals throughout the specification.

In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, so the present invention is not necessarily limited to what is shown. In the drawing, the thickness is enlarged to clearly express various layers and areas. And in the drawings, for convenience of explanation, the thicknesses of some layers and regions are exaggerated.

Additionally, when a part of a layer, membrane, region, plate, etc. is said to be “on” or “on” another part, this includes not only cases where it is “directly above” another part, but also cases where there is another part in between. . Conversely, when a part is said to be “right on top” of another part, it means that there is no other part in between. In addition, being “on” or “on” a standard part means being located above or below the standard part, and it necessarily means being “on” or “on” the direction opposite to gravity. no.

In addition, throughout the specification, when a part is said to "include" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

In addition, throughout the specification, when referring to “on a plane,” this means when the target part is viewed from above, and when referring to “in cross-section,” this means when a cross section of the target portion is cut vertically and viewed from the side.

Figure 4 is an exploded perspective view showing a battery module according to an embodiment of the present invention. Figure 5 is a plan view showing one of the battery cells included in the battery module of Figure 4. Figure 6 is a cross-sectional view showing a cross-section taken along the cutting line B-B' of Figure 5.

Referring to FIGS. 4 to 6 , the battery module 100 according to an embodiment of the present invention includes a battery cell stack 120 in which a plurality of battery cells 110 are stacked. First, the battery cell 110 included in the battery cell stack 120 according to this embodiment will be described in detail.

The battery cell 110 according to this embodiment includes an electrode assembly 110A including electrodes 111 and 112 and a separator 110S located between the electrodes 111 and 112; and a pouch case 114 in which the electrode assembly 110A is stored and the outer periphery is sealed. That is, the battery cell 110 according to this embodiment is a pouch-type battery cell and may have a rectangular sheet shape.

Each of the electrodes 111 and 112 includes electrode current collectors 111F and 112F and active material layers 111M and 112M formed on one or both sides of the electrode current collectors 111F and 112F. The electrodes 111 and 112 include an anode 111 and a cathode 112. More specifically, the positive electrode 111 may include a positive electrode current collector 111F and a positive electrode active material layer 111M formed by applying a positive active material to one or both sides of the positive electrode current collector 111F, and the negative electrode 112 It may include a negative electrode current collector 112F and a negative electrode active material layer 112M formed by applying a negative electrode active material to one or both surfaces of the negative electrode current collector 112F. The separator 110S is interposed between the anode 111 and the cathode 112 to block contact between the anode 111 and the cathode 112.

The battery cell 110 may be formed by storing the electrode assembly 110A in a pouch case 114 of a laminated sheet including a resin layer and a metal layer and then bonding the outer periphery of the pouch case 114. Specifically, the battery cell 110 is made by bonding both ends 114a and 114b of the pouch case 114 and one side 114c connecting them with the electrode assembly 110A stored in the pouch case 114. It can be manufactured by doing. In other words, the battery cell 110 according to an embodiment of the present invention has a total of three sealing portions 114S, and the sealing portions 114S have a structure that is sealed by bonding between the inner resin layers, which will be described later, and the remaining sealing portions 114S One side may be comprised of a folding portion 115.

The pouch case 114 of the laminate sheet may include an inner resin layer for sealing, a metal layer to prevent penetration of materials, and an outermost outer resin layer. Based on the electrode assembly inside the pouch case 114, the inner resin layer may be located at the innermost side, the outer resin layer may be located at the outermost side, and the metal layer may be located between the inner resin layer and the outer resin layer.

The outer resin layer has excellent tensile strength and weather resistance relative to the thickness and can be electrically insulating to protect the electrode assembly from the outside. This outer resin layer may include polyethylene terephthalate (PET) resin or nylon resin. The metal layer can prevent air, moisture, etc. from entering the pouch-type secondary battery. This metal layer may include aluminum (Al). The inner resin layers may be heat-sealed to each other by heat and/or pressure applied while the electrode assembly is embedded. This inner resin layer may include casted polypropylene (CPP) or polypropylene (PP).

The pouch case 114 is divided into two parts, and a concave storage part in which the electrode assembly can be seated may be formed in at least one of the two parts. Along the outer periphery of this storage portion, the inner resin layers of the two parts of the pouch case 114 may be bonded to each other to provide a sealing portion 114S. Heat and/or pressure may be applied to bond the inner resin layers together. In this way, the pouch case 114 can be sealed, and the pouch-shaped battery cell 110 can be manufactured.

The battery cells 110 are composed of a plurality of cells, and the plurality of battery cells 110 are stacked so that they can be electrically connected to each other to form the battery cell stack 120. In particular, as shown in FIG. 4, a plurality of battery cells 110 may be stacked along a direction parallel to the y-axis, with one side of the cell body 113 (see FIG. 5) facing each other.

Meanwhile, the electrode current collectors 111F and 112F according to the present embodiment include protrusions 111P and 112P formed by a portion of the electrode current collectors 111F and 112F protruding to the outside of the sealed pouch case 114. . That is, a portion of the electrode current collectors 111F and 112F extends to form protrusions 111P and 112P, and these protrusions 111P and 112P extend beyond the sealing portion 114S of the pouch case 114 and protrude to the outside. You can.

In FIG. 6 , only the protrusion 111P formed by extending a portion of the positive electrode current collector 111F is shown, but a portion of the negative electrode current collector 112F may be extended in the opposite direction to form the protrusion 112P. Accordingly, as shown in FIG. 5, in the battery cell 110, the protrusion 111P extending from the positive electrode current collector 111F may protrude toward the x-axis direction, and the protrusion extending from the negative electrode current collector 112F may protrude in the x-axis direction. (112P) may protrude toward the -x-axis direction.

A bus bar 500 is joined to these protrusions 111P and 112P. Specifically, the protrusions 111P and 112P and the bus bar 500 may be joined by welding. That is, in the case of the battery cell 110 according to this embodiment, the protrusions 111P and 112P formed by extending the electrode current collectors 111F and 112F are directly bonded to the bus bar 500, thereby integrating the battery cell and bus bar. A structure can be formed. In particular, with the protrusions 111P and 112P extending from the electrode current collectors 111F and 112F joined to the bus bar 500, the electrode assembly 110A is stored in the pouch case 114, and the pouch case 114 ) The outer periphery may be sealed to form a sealing portion 114S. To improve sealing properties and secure electrical insulation, a film 114F surrounding the protrusions 111P and 112P may be interposed between the sealing portions 114S. This film (114F) is a material with electrical insulation and bonding properties and is made of polyimide (PI), polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET). It may contain one or more materials selected from the group.

Unlike the conventional battery cell 11 in which the electrode lead 11L is used, the battery cell 110 according to the present embodiment directly connects the protrusions 111P and 112P formed by extending the electrode current collectors 111F and 112F. By joining to the bus bar 500, the area where welding is performed was minimized. That is, by removing the electrode lead 11L, welding resistance in the process of implementing electrical connection between the battery cells 110 included in the battery module 100 can be reduced. As the internal resistance is reduced, the voltage measurement error in the high-output battery module 100 can be reduced, and the heat generated by the battery cells 110 during charging and discharging can be reduced.

Hereinafter, the structure of the bus bar and the connecting bus bar according to this embodiment will be described in detail.

Figure 7 is a partial perspective view showing an enlarged portion of the battery cell stack and bus bar included in the battery module of Figure 4. Figure 8 is a partial perspective view for explaining the bolt fastening structure between a bus bar and a connecting bus bar according to an embodiment of the present invention.

Referring to Figures 4 and 6 to 8 together, the battery module 100 according to this embodiment includes a battery cell stack 120 in which a plurality of battery cells 110 are stacked, and a bus bar 500 ) are connected to each other by a mechanical fastening method to establish electrical connection between the battery cells 110. Here, the mechanical fastening method refers to a fastening method using physical restraint rather than a method using welding joints or adhesives. As long as electrical connection between the bus bars 500 is possible, there is no particular limitation on the mechanical fastening method applied in the present invention.

For example, the mechanical fastening method according to this embodiment may be bolt fastening, rivet fastening, clinching fastening, or fitting fastening. First, as an example of the mechanical fastening method of the present invention, the bolt fastening method will be described.

As described above, in the battery cell stack 120, the battery cells 110 may be stacked along one direction so that one side faces each other. FIG. 4 shows a plurality of battery cells 110 stacked upright along a direction parallel to the y-axis with one side of the cell body 113 (see FIG. 5) facing each other.

At this time, the bus bar 500 is joined to the protrusions 111P and 112P, as described above, to form a battery cell-busbar integrated structure. The battery module 100 may further include a connection bus bar 600 connecting the bus bars 500. Both the bus bar 500 and the connecting bus bar 600 may include a metal material with high electrical conductivity.

The connection bus bar 600 may be connected to at least two bus bars 500 by mechanical fastening. As an example of a mechanical fastening method, the connecting bus bar 600 may be connected to at least two bus bars 500 by fastening with bolts. For example, a through hole 500H may be formed in the bus bar 500, and a through hole 600H may also be formed in the connection bus bar 600. The bolt member 710 may pass through the through hole 500H of the bus bar 500 and the through hole 600H of the connection bus bar 600 and then be fastened to the nut member 720.

Since the battery cell 110 according to this embodiment has an integrated structure in which the bus bar 500 is already connected to the battery cell 110, a connecting bus bar 600 is used for electrical connection between the battery cells 110. The bolt fastening structure used was applied. Compared to a conventional battery module in which welding is performed between the electrode lead 11L and the bus bar 40, the bolt fastening structure using the connecting bus bar 600 can increase the degree of freedom in designing the battery module 100. It has advantages. This will be described later with reference to FIG. 11. In addition, the bolt fastening structure is easier to rework than welding, and there is no need to worry about loss due to poor welding between the electrode lead 11L and the bus bar 40. Other examples of mechanical fastening methods will be described again with reference to FIGS. 14 to 19.

Figure 9 is a perspective view showing a bus bar frame according to an embodiment of the present invention.

Referring to FIGS. 7 and 9 together, the battery module according to this embodiment may further include at least one bus bar frame 800 disposed on one or both sides of the battery cell stack 120. In FIG. 7 , only the bus bar 500 is shown for convenience of explanation, but the bus bar frame 800 may be located between the battery cell stack 120 and the bus bar 500.

Specifically, the bus bars 500 may be located on one side of the bus bar frame 800, and the battery cell stack 120 may face the other side of the bus bar frame 800. The protrusions 111P and 112P of the battery cell 110 may pass through the slit 800S formed in the bus bar frame 800.

Figure 10 is a front view showing a bus bar frame according to another embodiment of the present invention.

Referring to FIGS. 7 and 10 together, similar to the bus bar frame 800 of FIG. 9, the bus bar frame 800' according to another embodiment of the present invention includes a protrusion 111P of the battery cell 110, A slit (800S') through which 112P) can pass may be formed. Bus bars 500 are located on one side of the bus bar frame 800', and the other side of the bus bar frame 800' may face the battery cell stack 120.

At this time, since the protrusions 111P and 112P according to this embodiment are already joined to the bus bar 500, the bus bar according to this embodiment can be inserted into the slit 800S. The slit 800S' formed in the frame 800' may be a slit that is open toward the upper or lower side of the bus bar frame 800. As an example, Figure 10 shows a slit 800S' that is open toward the lower side of the bus bar frame 800. The protrusions 111P, which are already joined to the bus bar 500, may be inserted into the slit 800S' through the open lower part of the slit 800S'. Accordingly, the bus bars 500 are located on one side of the bus bar frame 800', and the other side of the bus bar frame 800' may face the battery cell stack 120.

Meanwhile, the busbar frames 800 and 800' may include an electrically insulating material. For example, the busbar frame (800, 800') may include a plastic material that is electrically insulating. The bus bar frames 800 and 800' are members arranged to prevent short circuits between the bus bars 500 and the battery cells 110.

Although not specifically shown, the bus bar frame 800 may be equipped with a terminal bus bar that functions as an external input/output terminal and a sensing assembly that transmits temperature and voltage information of the battery cell.

Figure 11 is a front view schematically showing a bus bar, a connecting bus bar, and a bus bar frame according to an embodiment of the present invention.

FIG. 11 roughly shows the bus bars 500 located on one side of the bus bar frame 800 and the connection bus bars 600a, 600b, and 600c connecting the bus bars 500.

The connection bus bars 600a, 600b, and 600c according to this embodiment may have various shapes. For example, the connection bus bars 600a, 600b, and 600c may be a bar-shaped metal member or a metal member with a bending portion. You can. The connecting bus bars 600a and 600b, which are rod-shaped metal members, can be adjusted in various lengths. Additionally, a bending portion may be freely provided in the connection bus bar 600c.

In this way, the bus bars 500 can be connected by applying connection bus bars 600a, 600b, and 600c having various shapes and sizes. Accordingly, the position and number of battery cells having the bus bar 500 can be freely set without limitation. That is, the mechanical fastening method using the connection bus bar 600 has the advantage of increasing the degree of freedom in design regarding the electrical connection method of the battery cells included in the battery module 100.

12 and 13 are cross-sectional views of battery cells according to different embodiments of the present invention, respectively.

First, referring to FIG. 12, like the previously described embodiment, the electrode lead is removed from the battery cell 110, and the protrusions 111P extending from the electrode current collector 111F are joined to the bus bar 500. . Additionally, in order to improve sealing properties and secure electrical insulation, a film 114F' surrounding the protrusions 111P and 112P may be interposed between the sealing portions 114S.

Compared to the removed electrode lead, the protrusion 111P extending from the electrode current collector 111F has relatively weak rigidity and can be easily damaged by external shock or vibration. In order to supplement the rigidity of the protrusion 111P, the film 114F' according to the present embodiment may cover the area where the protrusion 111P extends to be bonded to the bus bar 500. In other words, the film 114F' according to this embodiment can wrap the protruding part 111P up to the externally exposed portion of the sealing part 114S of the pouch case 114.

Next, referring to FIG. 13, the film (114F”) according to another embodiment of the present invention has not only an area where the protrusion (111P) extends to be bonded to the bus bar (500), but also a protrusion (111P) that extends to the bus bar (500). It can cover the part joined to 500 and at least a partial area of the bus bar 500. Through this, the rigidity of the portion where the protrusion 111P is exposed to the outside of the sealing portion 114S of the pouch case 114 as well as the portion where the protrusion 111P and the bus bar 500 are joined can be supplemented. Additionally, this film 114F” can increase electrical insulation by blocking the protrusion 111P or the bus bar 500 from contacting other parts. Instead, to facilitate bolt fastening between the bus bar 500 and the connection bus bar 600, the portion of the bus bar 500 connected to the connection bus bar 600 is not covered by the film (114F”). You can.

Meanwhile, referring again to FIG. 4, the battery module 100 according to this embodiment may further include a module frame 200 in which the battery cell stack 120 is accommodated. The module frame 200 is a member that accommodates the battery cell stack 120 therein, and may include two side portions 210 and 220, an upper surface portion 230, and a lower surface portion 240. Additionally, the module frame 200 may be open on both sides corresponding to the second direction and the opposite direction. The battery cell stack 120 can be accommodated through either of the two open sides. The module frame 200 may include a metal material with a predetermined strength to protect internal electrical components.

The module frame 200 shown in FIG. 4 may be a mono frame in which two side parts 210 and 220, an upper surface part 230, and a lower surface part 240 are integrated. That is, it may be manufactured by extrusion molding so that the two side parts 210 and 220, the upper surface part 230, and the lower surface part 240 are integrated. Although not specifically shown, as another embodiment of the present invention, a module frame in which a U-shaped frame and an upper plate are welded together is also possible. Looking at the stacking direction of the module frame 200 and the battery cells 110, one side of the battery cells 110, especially one side of the cell body 113 (see FIG. 5), is adjacent to the side portions 210 and 220 of the module frame 200. The battery cells 110 may be stacked from one side 210 to the other side 220 so as to be parallel to one side of the battery cells 110 .

Meanwhile, the battery module 100 according to this embodiment may further include end plates 300 located on both open sides of the module frame 200. The end plates 300 may be positioned to cover the battery cell stack 120 on both open sides of the module frame 200. The edges of each end plate 300 may be joined to the corresponding edges of the module frame 200 by welding. The end plates 300 may include a metal material with a predetermined strength and may protect the battery cell stack 120 and other electrical components from external shock. The bus bar frame 800 (see FIG. 9) described above may be located between the end plate 300 and the battery cell stack 120.

The battery module 100 may further include a thermal resin layer 400 located between the battery cell stack 120 and the lower surface 240 of the module frame 200. One side of the battery cells 110 may be adhered to the thermal resin layer 400. Specifically, the thermal resin layer 400 may be formed by injecting or applying thermal resin and then curing it. The thermal resin may include a thermally conductive adhesive material, and specifically may include at least one of silicone material, urethane material, or acrylic material. The thermal resin may be in a liquid state when applied, but may be cured after application and adhere to one side of the battery cell 110. Accordingly, the thermal resin layer 400 may serve to fix the battery cells 110. In addition, the thermal resin layer 400 has excellent heat conduction properties and can quickly transfer heat generated in the battery cell 110 to the lower side of the battery module.

Below, examples other than the bolt fastening method among the mechanical fastening methods of the present invention will be described.

Figures 14 and 15 are perspective views showing a rivet fastening method among mechanical fastening methods according to embodiments of the present invention. Specifically, FIG. 14 is a view showing before the rivet member is inserted, and FIG. 15 is a view showing after the rivet member is inserted and fastened. Figure 16 is a cross-sectional view taken along the cutting line C-C' of Figure 15.

Referring to FIGS. 14 to 16 , rivet fastening may be applied to the mechanical fastening between bus bars 500. Below, an example of a rivet fastening method will be described.

As previously described, the battery cell 110 may have a protrusion 111P that passes through the sealing portion 114S and is joined to the bus bar 500. A through hole 500H may be formed in the bus bar 500, and a through hole 600H may be formed in the connection bus bar 600. The rivet member 900 may fasten the through hole 500H of the bus bar 500 and the through hole 600H of the connecting bus bar 600.

The rivet member 900 before fastening has first and second ends 910 and 920 with different diameters. The diameter of the first end 910, which has a relatively large diameter, is larger than the diameter of the through hole 500H of the bus bar 500 and the diameter of the through hole 600H of the connecting bus bar 600. In addition, the diameter of the second end 920, which has a relatively small diameter, is smaller than the diameter of the through hole 500H of the bus bar 500 and the diameter of the through hole 600H of the connecting bus bar 600. The second end 920 may pass through both the through hole 500H of the bus bar 500 and the through hole 600H of the connecting bus bar 600.

After passing, force is applied to the second end 920 to change the shape of the second end 920. The first end 910 is not deformed and maintains its shape. The modified second end 920' is shown in FIGS. 15 and 16. The deformed second end 920' may be deformed similarly to the first end 910. That is, the diameter of the modified second end 920' may be larger than the diameter of the through hole 500H of the bus bar 500 and the diameter of the through hole 600H of the connection bus bar 600. In this way, while the rivet member 900 is passed through the through hole 500H of the bus bar 500 and the through hole 600H of the connecting bus bar 600, the shape of the second end 920 is changed. Riveting can be completed. The bus bar 500 and the connecting bus bar 600 may be electrically connected to each other while being closely adhered and fixed by the rivet member 900.

Figure 17 is a perspective view showing the clinching fastening method among the mechanical fastening methods according to embodiments of the present invention. Figure 18 is a cross-sectional view taken along the cutting line DD' of Figure 17.

Referring to FIGS. 17 and 18 , clinching fastening may be applied to the mechanical fastening between bus bars 500. Below, an example of clinching fastening will be described.

As previously described, the battery cell 110 may have a protrusion 111P that passes through the sealing portion 114S and is joined to the bus bar 500. The bus bar 500 and the connecting bus bar 600 may be connected to each other by a clinching method.

Specifically, press processing can be performed using a punch and a die while the bus bar 500 and the connecting bus bar 600 are in contact with each other. With the bus bar 500 and the connecting bus bar 600 supported by the die, a clinching hole (CH) can be formed while the punch presses the overlapping portion of the bus bar 500 and the connecting bus bar 600. there is. At this time, depending on the shape of the die, an interlock (IL) structure may be formed. The interlock structure (IL) can create bonding force using plastic deformation of the material and reverse flow, and accordingly, the bus bar 500 and the connecting bus bar 600 can be electrically connected to each other by being closely adhered and fixed. .

Figures 19 (a) and (b) are cross-sectional views illustrating a fitting coupling among the mechanical fastening methods according to embodiments of the present invention. Figure 19 (a) shows before the bus bar and the connection bus bar are combined, and Figure 19 (b) shows after the bus bar and the connection bus bar are combined.

Referring to Figures 19 (a) and (b), a fitting coupling may be applied to the mechanical connection between the bus bars 500. For example, an insertion groove 600G may be formed in one of the bus bar 500 and the connection bus bar 600, and the other one of the bus bar 500 and the connection bus bar 600 may be formed in this insertion groove ( 600G), the bus bar 500 and the connection bus bar 600 may be connected to each other. 19 (a) and (b) show that an insertion groove 600G is formed in the connection bus bar 600.

Additionally, an insertion groove 600G may be formed between the first part 610 and the second part 620 of the connection bus bar 600, and the first part 610 and the second part 620 may be connected to each other. It can have a shape that bends toward . When the bus bar 500 is inserted between the first part 610 and the second part 620, the first part 610 and the second part 620 function like a leaf spring, and the bus bar 500 ) may be fixed by the elastic force of the first part 610 and the second part 620. Accordingly, the bus bar 500 and the connecting bus bar 600 can be electrically connected to each other while being closely adhered and fixed. Although not specifically shown, an insertion groove is formed in the bus bar so that the connecting bus bar is inserted into the insertion groove of the bus bar, which is also possible in an embodiment of the present invention.

Figure 20 is a partial perspective view showing an enlarged portion of the battery cell stack and bus bar according to another embodiment of the present invention.

Referring to FIG. 20, in the battery cell stack 120 according to another embodiment of the present invention, the protrusions 111P of at least two battery cells 110 are joined to one bus bar 500'. It can be. The protrusion 111P protruding from the battery cell 110 is directly connected to the bus bar 500', and the protrusions 111P of several battery cells 110 can be connected to one bus bar 500'. To this end, the bus bar 500' may be further extended along the direction in which the battery cells 110 are stacked, and slits may be formed in the bus bar 500'. In Figure 20, as an example, the protrusions 111P of four or five battery cells 110 are shown being connected to one bus bar 500'. Several battery cells 110 can be electrically connected simply by joining several protrusions 111P to one bus bar 500'. That is, this embodiment has the advantage of reducing contact resistance because separate connections between bus bars are not necessary.

In this embodiment, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are only for convenience of explanation and may vary depending on the location of the target object or the location of the observer. .

One or more battery modules according to this embodiment described above may be mounted together with various control and protection systems such as a Battery Management System (BMS), Battery Disconnect Unit (BDU), and a cooling system to form a battery pack.

The battery module or battery pack can be applied to various devices. Specifically, it can be applied to transportation means such as electric bicycles, electric vehicles, and hybrids, or ESS (Energy Storage System), but is not limited to this 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 are also possible. falls within the scope of rights.

100: battery module
110: battery cell
110A: Electrode assembly
111, 112: electrode
111F, 112F: Electrode current collector
111M, 112M: active material layer
111P, 112P: Protrusion
114: Pouch case
114S: Sealing part
120: Battery cell laminate
200: module frame
300: End plate
400: Thermal resin layer
500: bus bar
500H: Through hole
600: Connection busbar
600H: Through hole
710: Bolt member
720: Nut member

Claims (18)

An electrode assembly including electrodes and a separator positioned between the electrodes; and
Includes a pouch case whose outer periphery is sealed while housing the electrode assembly,
The electrode includes an electrode current collector and an active material layer formed on one or both sides of the electrode current collector,
The electrode current collector includes a protrusion formed by a portion of the electrode current collector protruding to the outside of the sealed pouch case,
A battery cell in which a bus bar is bonded to the protrusion. In paragraph 1:
A battery cell in which the protrusion and the bus bar are joined by welding. In paragraph 1:
A battery cell in which the outer periphery of the pouch case is sealed while the protrusion is joined to the bus bar. In paragraph 1:
The outer periphery of the pouch case is sealed to form a sealing portion,
A battery cell in which a film surrounding the protrusion is interposed between sealing parts. In paragraph 4,
The film is a battery cell that surrounds the portion of the protrusion exposed to the outside of the sealing portion. In paragraph 4,
The film is a battery cell that surrounds the portion where the protrusion is joined to the bus bar and at least a partial area of the bus bar. Comprising a battery cell stack in which the battery cells according to claim 1 are stacked,
A battery module in which the bus bars are connected to each other through a mechanical fastening method, thereby providing electrical connection between the battery cells. In paragraph 7:
The mechanical fastening method is a battery module that is bolted, riveted, clinched, or fitted. In paragraph 7:
In the battery cell stack, the battery modules are stacked along one direction so that one side faces each other. In paragraph 7:
A battery module including a connection bus bar connecting the bus bars. In paragraph 10:
The connection bus bar is a battery module connected to at least two of the bus bars by mechanical fastening. In paragraph 11:
A through hole is formed in each of the bus bar and the connecting bus bar,
A battery module in which a bolt member passes through the through hole of the bus bar and the through hole of the connection bus bar and then is fastened with a nut member. In paragraph 11:
A through hole is formed in each of the bus bar and the connecting bus bar,
A battery module in which a rivet member fastens the through hole of the bus bar and the through hole of the connecting bus bar. In paragraph 11:
A battery module in which the bus bar and the connecting bus bar are connected to each other by a clinching fastening method. In paragraph 11:
The bus bar has an insertion groove formed in any one of the connection bus bars,
A battery module in which the other one of the bus bar and the connection bus bar is inserted into the insertion groove, and the bus bar and the connection bus bar are connected to each other. In paragraph 11:
The connection bus bar is a battery module that is a bar-shaped metal member or a metal member with a bending portion. In paragraph 7:
A battery module in which the protrusions of at least two of the battery cells are joined to one of the bus bars. In paragraph 7:
At least one bus bar frame is disposed on one or both sides of the battery cell stack,
The bus bar frame is a battery module located between the bus bar and the battery cell stack.