Electrode assembly and battery cell including the same

Abstract

In one embodiment of the present invention, an electrode assembly includes electrodes and separators stacked alternately, the separator includes an extension that protrudes beyond an end of the electrode in one direction of the electrode assembly, and a fixing member is formed between adjacent separator extensions in a direction in which the electrodes and separators are stacked among a plurality of separators included in the electrode assembly.

Description

Technical Field

[0001] Cross - reference to related applications This application claims the benefit of priority based on Korean Patent Application No. 10 - 2021 - 0127163 filed on September 27, 2021 and Korean Patent Application No. 10 - 2022 - 0114320 filed on September 8, 2022, and all the contents disclosed in the documents of the Korean patent applications are included as part of this specification.

[0002] The present invention relates to an electrode assembly and a battery cell including the same, and more specifically, to an electrode assembly in which a folding phenomenon of a separator is prevented and a battery cell including the same.

Background Art

[0003] In modern society, as the use of portable devices such as mobile phones, notebook computers, video cameras, and digital cameras has become common, technological development in the field related to such mobile devices has become active. In addition, rechargeable secondary batteries are used as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug - in hybrid electric vehicles (P - HEVs), etc. as a measure to solve problems such as air pollution of existing gasoline vehicles that use fossil fuels. Therefore, the need for the development of secondary batteries is increasing.

[0004] Currently commercialized secondary batteries include nickel - cadmium batteries, nickel - metal hydride batteries, nickel - zinc batteries, lithium secondary batteries, etc. Among these, lithium secondary batteries have the advantages of free charge and discharge, low self - discharge rate, and high energy density, and are the most widely noted.

[0005] Secondary batteries are classified into cylindrical batteries and prismatic batteries in which the electrode assembly is built into a cylindrical or prismatic metal can according to the shape of the battery case, and pouch - type batteries in which the electrode assembly is built into a pouch - type case of an aluminum laminate sheet.

[0006] In addition, secondary batteries may be classified according to the structure of the electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are laminated. Typically, there are a jelly roll type (winding type) electrode assembly having a structure in which a long sheet-shaped positive electrode and negative electrode are wound with a separator interposed therebetween, and a stack type (lamination type) electrode assembly in which a plurality of positive electrodes and negative electrodes cut into units of a predetermined size are sequentially laminated with a separator interposed therebetween. Recently, in order to solve the problems of the jelly roll type electrode assembly and the stack type electrode assembly, a stack / folding type electrode assembly, which is a hybrid form of the jelly roll type and the stack type, has also been developed.

[0007] FIG. 1 is a side view of a conventional electrode assembly. FIG. 2 is a photograph of the side of a conventional electrode assembly. FIG. 3 is a diagram illustrating a test regarding the rigidity of a conventional electrode assembly.

[0008] Referring to FIG. 1, the electrode assembly is a stack type electrode assembly, and is mainly formed by laminating unit cells in which a positive electrode 11, a separator 13, a negative electrode 12, and a separator 13 are laminated, or unit cells in which a negative electrode 12, a separator 13, a positive electrode 11, and a separator 13 are sequentially laminated.

[0009] On the other hand, usually, since the separator 13 is formed larger than the positive electrode 11 or the negative electrode 12, the end of the separator 13 exists in a state where it is not adhered to the positive electrode 11 or the negative electrode 12 in the electrode assembly, and thus, a problem may occur in which the end of the separator 13 is folded by an external force as in the A region of FIG. 2. Further, as shown in FIG. 3, when an uneven force is applied to the electrode assembly, the overall stiffness of the electrode assembly may decrease, such as being prone to warping. In particular, such problems may occur more significantly in the long side than in the short side of the separator 13. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] The problem to be solved by the present invention is to provide an electrode assembly in which the folding phenomenon of the separation membrane of the electrode assembly is improved and the overall rigidity is enhanced, and a battery cell including the same.

[0011] However, the problem to be solved by the embodiments of the present invention is not limited to the above-described problems, and can be variously extended within the scope of the technical idea included in the present invention.

Means for Solving the Problem

[0012] In an electrode assembly according to an embodiment of the present invention, electrodes and separation membranes are alternately laminated, and in one direction of the electrode assembly, the separation membrane has a structure longer than the electrodes. As a result, the separation membrane includes an extension portion that protrudes beyond the ends of the electrodes, and among the plurality of separation membranes included in the electrode assembly, a fixing member is formed to fix between the extension portions of the separation membranes adjacent to each other along the direction in which the electrodes and the separation membranes are laminated.

[0013] The fixing member has a web structure including at least one line constituting a plurality of line sections, and the web structure can include at least one intersection formed by two or more line sections.

[0014] The line width of the lines of the web structure may be 20 to 100 μm.

[0015] The interval between adjacent lines of the web structure may be 100 to 800 μm.

[0016] The fixing member can include a pattern shape having a large number of openings.

[0017] The electrode assembly has a side surface defined in the direction (Y direction) in which the electrodes and the separation membranes are laminated, and the fixing member is formed by partially applying an adhesive along the lamination direction (Y direction).

[0018] The electrode assembly further includes an electrode tab protruding from one end of the electrode, and the direction in which the electrode tab protrudes may be the same as the electrical installation direction.

[0019] The separation membrane can have a zigzag shape formed by bending a rectangular sheet.

[0020] A finished separation membrane can be located outside the fixing member.

[0021] The separation membrane has long sides facing each other and short sides facing each other, and the fixing member is formed on the long side of the separation membrane.

[0022] The fixing member is formed to cover 70% to 80% of one side surface of the electrode assembly.

[0023] The electrode includes a positive electrode and a negative electrode, and the end of the positive electrode can be separated from the fixing member.

[0024] The thickness of the fixing member may be 100 to 600 μm.

[0025] The fixing member covers an extension of the separation membrane, and the fixing member is arranged at the same height as the extension of the separation membrane.

[0026] The fixing member can include an adhesive.

[0027] A battery cell according to another embodiment of the present invention includes the above-described electrode assembly.

Advantages of the Invention

[0028] According to the embodiment, the electrode assembly of the present invention and the battery cell including the same include fixing members applied to both ends of the electrode assembly, thereby improving the folding phenomenon of the separation membrane and improving the overall rigidity.

[0029] 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.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Modes for Carrying Out the Invention

[0031] Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement them. The present invention can be realized in various different forms in addition to those described below, and the scope of the present invention is not limited by the embodiments described here.

[0032] In order to clearly explain the present invention, parts that are unnecessary for the explanation are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

[0033] Also, the sizes and thicknesses of the respective components shown in the drawings are arbitrarily enlarged or reduced for the convenience of explanation, so it is obvious that the content of the present invention is not limited to what is shown in the drawings. In the following drawings, the thicknesses of the respective layers are enlarged to clearly show various layers and regions. And in the following drawings, for the convenience of explanation, the thicknesses of some layers and regions are exaggerated.

[0034] Also, when a part such as a layer, film, region, or plate is described as being "on" another part, this should be interpreted to include not only the case where the part such as the layer, film, region, or plate is directly "on" the other part, but also the case where there are other parts in between. Conversely, when the part such as the layer, film, region, or plate is described as being "directly on" the other part, it can mean that there are no other parts in between. Furthermore, being "on" the reference part means being located above or below the reference part, and does not necessarily mean being located "upward" in the opposite direction of gravity. On the other hand, similar to the description of being "on" another part, the description of being "under" another part can also be understood with reference to the above-described content.

[0035] Also, throughout the specification, when a part "includes" a certain component, this means that, unless otherwise stated, it does not exclude other components but can further include other components.

[0036] Furthermore, throughout the specification, when referring to "on a plane", it means when looking at the relevant part from above, and when referring to "in a cross-section", it means when looking at the cross-section obtained by vertically cutting the relevant part from the side.

[0037] Hereinafter, an electrode assembly according to an embodiment of the present invention will be described.

[0038] FIGS. 4 and 5 are diagrams showing an electrode assembly according to an embodiment of the present invention.

[0039] Referring to FIGS. 4 and 5, the electrode assembly 100 of this embodiment is a charge-dischargeable power generation element and can include electrodes (positive electrode 110, negative electrode 120) and a separator 130. The electrodes (positive electrode 110, negative electrode 120) included in the electrode assembly 100 can include the positive electrode 110 and the negative electrode 120. By interposing the separator 130 between each electrode (positive electrode 110, negative electrode 120), the electrode assembly 100 can have a structure in which the positive electrode 110 / separator 130 / negative electrode 120 are alternately laminated. Here, the positions of the positive electrode 110 and the negative electrode 120 shown in FIGS. 4 and 5 are shown for convenience, and their positions can be mutually changed.

[0040] Further, the electrode assembly 100 of this embodiment may include a fixing member 140 formed on at least one side surface or both side surfaces. The fixing member 140 may include a fixing member 140 formed on the side surface of a cell laminate in which electrodes (positive electrode 110, negative electrode 120) and a separator 130 are alternately laminated. Here, the cell laminate means a laminate of electrodes (positive electrode 110, negative electrode 120) and a separator 130 in the electrode assembly 100 of this embodiment, and may not include the fixing member 140. Also, here, the side surface of the cell laminate may refer to a surface on which the ends of a plurality of electrodes (positive electrode 110, negative electrode 120) and / or the separator 130 are exposed in the cell laminate in which the electrodes (positive electrode 110, negative electrode 120) and the separator 130 are alternately laminated. Further, the side surface of the cell laminate may refer to one surface of the cell laminate that extends long along the electrical installation direction (the Z-axis direction in FIG. 4 or the long extending direction in FIG. 4), which is the first direction of the electrode assembly 100. The length (the length of the long side) of the electrode assembly 100 measured along the first direction is larger than the length (the length of the short side) of the electrode assembly 100 that extends along the second direction intersecting the first direction.

[0041] During the manufacture of the electrode assembly 100, in the long side direction and / or the short side direction, the size of the separator 130 is provided to be larger than the size of the electrodes (positive electrode 110, negative electrode 120), and the ends of the separator 130 can protrude beyond the ends of the electrodes (positive electrode 110, negative electrode 120). Specifically, in one direction of the electrode assembly 100 (the X-axis direction in FIG. 4 or the direction extending horizontally in FIG. 4), since the separator 130 has a structure longer than the electrodes (positive electrode 110, negative electrode 120), the separator 130 includes an extension portion 138 that protrudes beyond the ends of the electrodes (positive electrode 110, negative electrode 120). At this time, the extension portion 138 may be formed on one of the left and right sides of the electrodes (positive electrode 110, negative electrode 120), or may be formed on both sides so as to face each other.

[0042] Further, as will be described later, when the electrode assembly 100 is formed by zigzag lamination, the bent portion of the separator 130 can protrude beyond the ends of the electrodes (the positive electrode 110 and the negative electrode 120). Here, the end of the protruding separator 130 or the bent portion of the separator 130 is referred to as an "extension portion 138".

[0043] The fixing member 140 is formed by applying an adhesive. The adhesive can contain components that are difficult to dissolve in the electrolytic solution. Examples of the adhesive used for the fixing member 140 include PO, PUR, EVA, and rubber-based adhesives. Further, as other examples, curable adhesives capable of natural curing, moisture curing, UV curing, etc. can be mentioned.

[0044] The fixing member 140 may fix the form of the separator 130 by contacting the extension portion 138 of the separator 130 that does not contact the electrodes (the positive electrode 110 and the negative electrode 120). The separator 130 and at least one other separator 130 adjacent thereto can be connected to each other by the fixing member 140. A plurality of or all of the separators 130 of the electrode assembly 100 can be connected using at least one fixing member 140.

[0045] The fixing member 140 can be in contact with the separator 130. At this time, as shown in FIG. 4, the fixing member 140 may be formed between the separators 130 so as to correspond to the position of the extension portion 138 of the separator 130, or as shown in FIG. 5, it may be formed to cover up to the outside of the extension portion 138 of the separator 130. At this time, the fixing member 140 is disposed at the same height as the extension portion 138 of the separator 130. Specifically, as shown in FIG. 5, the fixing members 140 can be coupled to each other over various levels in the stacking direction, and such coupling is performed by a fixing member portion 142 that extends to the periphery of the outermost corner portion of the separator 130.

[0046] The fixing member 140 preferably does not contact the positive electrode 110. That is, the end of the positive electrode 110 is separated from the fixing member 140. This is because the fixing member 140 hinders the flow of ions moving from the positive electrode 110 to the negative electrode 120. Also, although the fixing member 140 preferably does not contact the negative electrode 120, since the negative electrode 120 is not a direct charging region, the influence is less than when the positive electrode 110 and the fixing member 140 are in contact.

[0047] The fixing member 140 may be formed on all side surfaces of the electrode assembly 100, but is preferably formed only on some side surfaces. This is because when the fixing member 140 is formed on all side surfaces of the electrode assembly 100, gas release of the electrode assembly 100 is hindered by the fixing member 140 during the electrolyte impregnation or activation process of the electrodes (positive electrode 110, negative electrode 120).

[0048] When referring to the embodiments shown in the drawings, the surfaces facing the long side direction that extends long are referred to as the front surface or the rear surface. The surfaces facing the short side direction that extends horizontally are referred to as the left side surface or the right side surface.

[0049] The fixing member 140 may be formed to cover all of one side surface of the electrode assembly 100, or may be formed to cover 70 - 80% of the side surface. In particular, it can cover the entire height of the side surface in the stacking direction. Here, the side surface of the electrode assembly 100 can have a "height" formed by stacking. Also, the side surface of the electrode assembly 100 can have a "width" corresponding to the length of the long side or the short side. At this time, the fixing member 140 is formed to block 70 - 80% of the width of the side surface of the electrode assembly 100. By the fixing member 140 not completely blocking the side surface of the electrode assembly 100, it is possible to prevent the gas release of the electrode assembly 100 from being hindered by the fixing member 140 during the electrolyte impregnation or activation process of the electrodes (positive electrode 110, negative electrode 120).

[0050] The connecting member (fixed member 140) is formed on the surface of the side of the electrode assembly 100 where the long side of the separation membrane 130 is located. The fixed member 140 is formed on the long side of the separation membrane 130. This is because folding phenomena and the like occur more frequently on the long side, which is relatively longer than the short side of the separation membrane 130. However, such an explanation does not completely exclude the formation of the fixed member 140 on the short side of the separation membrane 130.

[0051] FIG. 6 is a photograph of the side surface of the electrode assembly. FIG. 7 is a diagram illustrating a test regarding the rigidity of the electrode assembly.

[0052] Referring to FIGS. 6 and 7, the phenomenon of the end of the separation membrane 130 being folded is prevented by the fixed member 140, and the rigidity of the electrode assembly 100 can be complemented.

[0053] Specifically, it was confirmed that by forming the fixed member 140 on the side surface of the electrode assembly 100, the folding phenomenon that appeared in the A region of FIG. 2 described above was improved. Also, in the same test as that performed in FIG. 3, since the phenomenon of a part of the electrode assembly 100 tilting does not occur in FIG. 7, it was confirmed that the minimum rigidity required for the electrode assembly 100 was ensured by the fixed member 140. By thus complementing the rigidity of the electrode assembly 100, excessive deformation of the electrode assembly 100 can be prevented when an external force is applied.

[0054] FIG. 8 is a diagram showing an example of an apparatus for applying an adhesive to the electrode assembly and the applied adhesive. FIG. 9 is a diagram showing another example of an apparatus for applying an adhesive to the electrode assembly and the applied adhesive.

[0055] Referring to FIGS. 8, 10, and 11, the fixed member 140 of this embodiment is formed of an adhesive material line 144 in a network form such as a web structure. The adhesive material line 144 includes a plurality of nodes or intersection points (intersection point 146) where one adhesive material line 144 can intersect or cross the other adhesive material line 144.

[0056] The web structure can be realized by a pattern method. The pattern method is realized by using one or more, for example, four printing units, and the four printing units can be driven on the side where the fixing member is provided by a random or preset pattern. Here, the pattern method can mean applying the adhesive 10 so that the adhesive 10 applied to the target position has a predetermined pattern. The illustrated pattern is a pig tail pattern, but other patterns can be applied as well.

[0057] The pattern method adhesive application device 200 can include a housing 210 and a nozzle 220. The adhesive 10 is supplied from the outside of the device (adhesive application device 200) and housed in the housing 210, and the adhesive 10 that has passed through the nozzle 220 is discharged linearly. The applied adhesive 10 can have a specific pattern by the movement of the nozzle 220. As an example, below FIG. 8, it is shown that by applying the adhesive 10 in a spiral shape, it has the shape of a web structure in which a large number of circles overlap. Such a shape of the web structure may be referred to as a pig tail shape or a pig tail pattern.

[0058] Referring to FIG. 9, the fixing member 140 of this embodiment is formed by a surface coating method. Here, the surface coating method can mean applying the adhesive 10 densely so that the adhesive 10 is applied to the target position without gaps.

[0059] The adhesive application device 300 of the surface coating method can apply the adhesive 10 so that the adhesive 10 covers all the target parts, as shown in the photo below Figure 9. The adhesive application device 300 of the surface coating method can apply the adhesive by spraying, slotting or other methods. As an example, the adhesive application device 300 of the surface coating method can include a housing 310, a nozzle 320, a tube 330 through which the adhesive 10 is supplied inside the housing 310, and an air tube 340 for injecting compressed air when the adhesive 10 is ejected through the nozzle 320 connected to the tube 330.

[0060] On the other hand, since the adhesive application device 300 of the surface coating method shown in Figure 9 uses compressed air or the like, there is a risk of a scattering phenomenon in which the adhesive 10 scatters when the adhesive 10 is ejected. Also, when trying to increase the thickness of the fixing member 140, there is a demerit that the uniformity of the fixing member 140 decreases.

[0061] In contrast, since the adhesive application device 200 shown in Figure 8 discharges the adhesive 10 in a linear shape, the scattering phenomenon of the adhesive due to air or the like is minimized, and the contamination of the device is minimized. Also, the device (adhesive application device 200) shown in Figure 8 can relatively freely adjust the density and thickness of the fixing member 140 by adjusting the interval between the lines. The device (adhesive application device 200) shown in Figure 8 can apply the adhesive 10 more uniformly than the adhesive application device 300 shown in Figure 9 even when trying to increase the thickness of the fixing member 140 by applying the adhesive 10 in a certain pattern.

[0062] The device (adhesive application device 200) shown in Figure 8 can minimize the thickness of the fixing member 140 compared to the device (adhesive application device 300) shown in Figure 9. Specifically, the thickness of the fixing member 140 formed by the device (adhesive application device 200) shown in Figure 8 is about 100 μm or more, while the thickness of the fixing member 140 formed by the device (adhesive application device 300) shown in Figure 9 may be about 200 μm or more. This is because, as described above, the device (adhesive application device 200) shown in Figure 8 applies the adhesive 10 in a linear shape.

[0063] The thickness of the fixing member 140 formed on the electrode assembly 100 can be variously set according to the design. For example, the thickness of the fixing member 140 can be designed to be less than the size of the separation space between the electrode assembly 100 inside the battery cell and the battery case. As a specific example, when the electrode assembly 100 is built into the battery case without the fixing member 140 being formed, the separation distance between the electrode assembly 100 and the battery case may be around 600 μm. In this case, the thickness of the fixing member 140 formed on the electrode assembly 100 may be 600 μm or less, 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less. Also, the thickness of the fixing member 140 formed on the electrode assembly 100 may be 100 - 600 μm, 100 - 500 μm, 100 - 400 μm, 100 - 300 μm, or 100 - 200 μm. At this time, the fixing member 140 is formed by repeatedly laminating lines by the device in FIG. 8 (adhesive application device 200).

[0064] The adhesive 10 provided by the adhesive application device can have a predetermined temperature. This is because the adhesive application device adjusts the temperature of the adhesive 10 so that the adhesive 10 can be easily applied. The operating temperature of the device in FIG. 8 (adhesive application device 200) is 110 °C, and the temperature of the adhesive 10 discharged from the device (adhesive application device 200) may be at the level of 40 °C - 50 °C. The operating temperature of the device in FIG. 9 (adhesive application device 300) is 160 °C, and the temperature of the adhesive 10 discharged from the device (adhesive application device 200) may be at the level of 60 °C - 70 °C. If the temperature of the adhesive 10 is high, the separation membrane 130 is likely to shrink. Therefore, it is preferable that the device in FIG. 8 (adhesive application device 200) be used for forming the fixing member 140 of this embodiment rather than the device in FIG. 9 (adhesive application device 300).

[0065] FIG. 10 is a photograph comparing the adhesives applied using the devices in FIGS. 8 and 9. FIG. 11 is a magnified photograph of region B in FIG. 10.

[0066] Referring to FIGS. 10 and 11, the application shape of the adhesive by the devices of FIGS. 8 and 9 can be compared. The shape is the shape of the fixing member 140 applied to the side surface of the electrode assembly 100.

[0067] FIG. 10(a) is by the pattern method and is formed by the device 200 of FIG. 8. In FIG. 10(a), the adhesive 10 discharged in a line shape is repeated, and for example, as shown in the drawing, the line shape is repeated in a spiral or circular shape to form a pattern. The fixing member 140 formed by the pattern method can have a pattern in which at least two lines intersect. In particular, a structure formed by one or more lines constituting a line section where a part intersects, especially a planar structure, is generally referred to as a web structure. The web structure can include at least one intersection formed by two or more line sections.

[0068] The fixing member 140 formed by the pattern method can include a large number of openings. The line width of the adhesive 10 by the pattern method may be 20 to 100 μm, and the interval between the lines may be 100 to 800 μm.

[0069] Referring to FIG. 11, it was more clearly confirmed that the fixing member 140 has a pig's tail pattern. The first line width d1 measured from the photograph was confirmed to be 50 μm, and the first line interval w1 was 600 μm.

[0070] On the other hand, FIG. 10(b) is by the surface coating method and is formed by the device (adhesive coating device 300) of FIG. 9. FIG. 10(b) is coated so as to form one surface without an interval between the adhesives 10. In FIG. 10(b), unlike FIG. 10(a), a pattern formed by the intersection of at least two lines was not found, and it was confirmed that no opening was formed in the fixing member 140.

[0071] On the one hand, since the fixing member 140 of the present embodiment is formed on the side surface of the electrode assembly 100, it may prevent the electrolytic solution absorbed through the side surface of the electrode assembly 100 from contacting the electrodes (positive electrode 110, negative electrode 120). Therefore, the fixing member 140 must be formed in such a way that the reduction in the absorption of the electrolytic solution is minimized.

[0072] FIG. 12 is a photograph taken of a test regarding the wettability of an electrode assembly to which the processes of FIGS. 8 and 9 are applied. Specifically, FIG. 12 shows the electrode assembly 100 having the fixing member 140 formed by the processes of FIGS. 8 and 9 after being impregnated with an electrolytic solution and then disassembled. Through the photograph, the portion where the electrolytic solution is not absorbed by the electrodes (positive electrode 110, negative electrode 120) is confirmed as the non-wetting region 20, and based on this, it can be confirmed whether the wettability of the electrodes (positive electrode 110, negative electrode 120) with respect to the electrolytic solution is reduced by the fixing member 140. Here, it can be said that the smaller the non-wetting region 20, the more sufficient the contact between the electrodes (positive electrode 110, negative electrode 120) and the electrolytic solution was.

[0073] Referring to FIG. 12, it can be confirmed that the non-wetting region 20 of the electrodes (positive electrode 110, negative electrode 120) in FIG. 12(a) to which the pattern method of FIG. 8 is applied is formed smaller than the electrodes (positive electrode 110, negative electrode 120) in FIG. 12(b) to which the surface coating method of FIG. 9 is applied. In other words, the fixing member 140 formed according to FIG. 8 does not prevent the absorption of the electrolytic solution more than the fixing member 140 formed according to FIG. 9.

[0074] Since the pattern coating method of FIG. 8 has a pattern in which a large number of lines intersect, it is formed to include a large number of openings in the fixing member 140. When the electrode assembly 100 is impregnated with an electrolytic solution, the electrolytic solution can be absorbed into the electrode assembly 100 through the openings. Therefore, the fixing member 140 by the pattern coating method can minimize the reduction in the penetration of the electrolytic solution compared to the fixing member 140 by the surface coating method.

[0075] If the electrolyte is not well absorbed by the electrodes (positive electrode 110, negative electrode 120), the output characteristics of the electrode assembly 100 may deteriorate. Therefore, even when the fixing member 140 is formed by the surface coating method of FIG. 9, the absorption rate of the electrolyte can also be increased by partially forming the fixing member 140 on the side surface of the electrode assembly 100. However, when the fixing member 140 is partially formed in this way, as shown in FIG. 3, the rigidity of the electrode assembly 100 may decrease, so the application position and application level of the fixing member 140 must be designed more finely.

[0076] Hereinafter, an electrode assembly according to another embodiment of the present invention will be described.

[0077] Prior to the description, it is clarified that the electrode assembly of this embodiment is the same as the content of the above-described electrode assembly except that the shape of the cell laminate is different. Therefore, even without separate mention, it can be explained that the electrode assembly according to this embodiment includes all the content related to the electrode assemblies of FIGS. 4 to 12 described above.

[0078] FIGS. 13 and 14 are diagrams showing an electrode assembly according to another embodiment of the present invention.

[0079] Referring to FIGS. 13 and 14, the electrode assembly 100 of this embodiment can include a cell laminate in which a positive electrode 110 / a separator 130 / a negative electrode 120 are alternately laminated, and finishing separators 132 and 134 surrounding the side surfaces of the cell laminate. Here, the separator 130 has a zigzag shape formed by bending a rectangular separator sheet, and the separator 130 bent in a zigzag can be interposed between the positive electrode 110 and the negative electrode 120. After the zigzag lamination is completed, the separator 130 can surround the side surface of the cell laminate at least once or more through the finishing separators 132 and 134, thereby finishing the side surface of the cell laminate. At this time, the positions of the positive electrode 110 and the negative electrode 120 shown in FIGS. 13 and 14 are shown for convenience, and the positions can be mutually changed.

[0080] A fixing member 140 is formed on the side surface of the cell laminate. The fixing member 140 contacts the extension 138 of the separator 130 and can fix the form of the separator 130 by connecting the extension 138. The fixing member 140 can fix the overall form of the separator 130 by connecting the bent portion of the separator 130, that is, the bent portion 138B of the separator 130. The overall shape of the cell laminate including the separator 130 is fixed by the fixing member 140, and a minimum rigidity can be ensured.

[0081] As described above, the fixing member 140 can be formed on all side surfaces of the cell laminate, but as shown in FIGS. 13 and 14, it may be formed on both side surfaces where the bent separator 130 is located. Also, different from FIGS. 13 and 14, it is also possible to be formed on other side surfaces of the cell laminate. However, since the gas release of the electrode assembly 100 may be hindered by the fixing member 140 during the electrolyte impregnation or activation process of the electrodes (positive electrode 110, negative electrode 120), the position of the fixing member 140 needs to be appropriately designed, and it is not preferable to be formed so as to cover all side surfaces of the cell laminate. Also, the fixing member 140 may be formed so as to cover all of one side surface of the electrode assembly 100, or may be formed so as to cover 70 - 80% of the side surface.

[0082] After the fixing member 140 is formed on the cell laminate, finishing separators 132, 134 are formed outside the fixing member 140. The finishing separators 132, 134 can surround the side surface of the cell laminate on which the fixing member 140 is formed. At this time, as shown in FIG. 13, the finishing separator 132 is finished after surrounding the side surface of the cell laminate once by surrounding the cell laminate once all around. Also, the finishing separators 132, 134 may be finish - processed after surrounding the side surface of the cell laminate two or more times by surrounding the cell laminate two or more times as shown in FIG. 14.

[0083] On the other hand, in the electrode assembly 100, even if the finishing separator membranes 132 and 134 are not formed, the side surface of the cell laminate may be finished by attaching an adhesive means such as heat fusion or an adhesive tape. The finishing method can be variously changed and implemented in any number of ways other than the above-described embodiments.

[0084] Hereinafter, a method for manufacturing an electrode assembly according to an embodiment of the present invention will be described.

[0085] The manufacturing method S1000 of the electrode assembly of the present embodiment can include a step S1100 of forming a cell laminate in which electrodes (positive electrode 110, negative electrode 120) and a separator membrane 130 are alternately laminated, a step S1200 of applying an adhesive 10 to the side surface of the cell laminate, and a step S1300 of forming a fixing member 140 for fixing the separator membrane 130.

[0086] Here, in the step S1100 of forming the cell laminate, any known method may be used as long as the electrodes and the separator membrane are laminated in the order of the positive electrode 110, the separator membrane 130, the negative electrode 120, the separator membrane 130, or in the order of the negative electrode 120, the separator membrane 130, the positive electrode 110, the separator membrane 130. For example, the cell laminate may be manufactured in a stack type as shown in FIGS. 4 and 5, or may be manufactured in a zigzag shape as shown in FIGS. 13 and 14.

[0087] Here, for the step S1200 of applying an adhesive to the side surface of the cell laminate, the device in FIG. 8 (adhesive application device 200) may be used, or the application device 300 in FIG. 9 may be used. When using the device in FIG. 8 (adhesive application device 200), the step S1200 can include a step of determining the application pattern of the adhesive 10 and / or a step of pattern-applying the adhesive by moving the nozzle 220 in the determined pattern. Here, the step of determining the application pattern of the adhesive 10 may be performed before the step S1100 of forming the cell laminate.

[0088] Since the adhesive 10 is applied in a viscous state, it is preferable to fix the form of the adhesive 10 by removing the solvent or moisture in the adhesive. In this case, the step S1300 of forming the fixing member 140 may include the step of drying the adhesive 10. Also, depending on the inherent properties of the adhesive 10, the adhesive 10 may be solidified by heat curing or UV curing. In this case, the step S1300 of forming the fixing member 140 may include the step of curing the adhesive 10.

[0089] On the other hand, in the case of the method for manufacturing the zigzag type electrode assembly 100 shown in FIGS. 13 and 14 of the present embodiment, the above-described manufacturing method may further include a step S1400 of finishing the side surface of the cell stack. By this step, finishing separation films 132 and 134 are formed on the side surface of the cell stack. The finishing separation films 132 and 134 are subjected to finishing treatment after surrounding the side surface of the cell stack at least once or more. The finishing separation films 132 and 134 may surround the side surface of the cell stack once as shown in FIG. 13, or may surround the side surface of the cell stack two or more times as shown in FIG. 14.

[0090] Also, the method for manufacturing the electrode assembly 100 according to the present embodiment may further include a step of applying pressure along one direction (X-axis direction) toward the side surface of the cell stack after the formation of the finishing separation films 132 and 134. When such a step is added, the finishing separation films 132 and 134 and the fixing member 140 adhere to each other, and the overall stiffness of the electrode assembly can be further improved. Moreover, there is also an effect that the finishing separation films 132 and 134 wind the electrode assembly more strongly. Thereby, it is possible to prevent the battery cell from warping.

[0091] On the other hand, the electrode assembly 100 of the present embodiment described above can be provided as a battery cell by being housed in a cell case together with an electrolytic solution.

[0092] A battery cell according to an embodiment of the present invention can include an electrode assembly 100 in which a plurality of electrodes and a plurality of separator membranes are alternately laminated, an electrode lead connected to an electrode tab extending from the plurality of electrodes, and a cell case that seals the electrode assembly with one end of the electrode lead protruding.

[0093] On the other hand, the above-described battery cell can be laminated in one direction to form a battery cell stack, and can be modularized into a battery module to form a battery pack together with a battery management system (BMS) that manages the temperature, voltage, etc. of the battery and / or a cooling device, etc. The battery pack can be applied to various devices. For example, the devices to which the battery pack is applied may be means of transportation such as electric bicycles, electric vehicles, and hybrid vehicles. However, the above-described devices are not limited thereto, and in addition to the above examples, the battery pack according to this embodiment may be used for various devices, and this also belongs to the scope of the present invention.

[0094] As described above, the preferred embodiments of the present invention have been described in detail, but 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 concepts of the present invention defined in the following claims also belong to the scope of the present invention.

Explanation of Reference Numerals

[0095] 100: Electrode assembly 110: Positive electrode 120: Negative electrode 130: Separator membrane 132, 134: Finishing separator membrane 138: Extension part 140: Fixing member 144: Adhesive material line 146: Intersection point 200, 300: Coating device 210, 310: Housing 220, 320: Nozzle 340: Air pipe

Claims

1. In an electrode assembly in which electrodes and separation membranes are alternately laminated, In one direction of the electrode assembly, the separation membrane has a structure longer than the electrode, whereby the separation membrane includes an extension portion protruding beyond the end of the electrode. Among the plurality of separation membranes included in the electrode assembly, a fixing member is formed to fix between the extension portions of the adjacent separation membranes along the direction in which the electrode and the separation membrane are laminated. The fixing member has a web structure including at least one line constituting a plurality of line sections. The web structure includes at least one intersection formed by two or more line sections, and the electrode assembly.

2. The electrode assembly according to claim 1, wherein the line width of the lines of the web structure is 20 to 100 μm.

3. The electrode assembly according to claim 1, wherein the interval between adjacent lines of the web structure is 100 to 800 μm.

4. In an electrode assembly in which electrodes and separation membranes are alternately laminated, In one direction of the electrode assembly, the separation membrane has a structure longer than the electrode, whereby the separation membrane includes an extension portion protruding beyond the end of the electrode. Among the plurality of separation membranes included in the electrode assembly, a fixing member is formed to fix between the extension portions of the adjacent separation membranes along the direction in which the electrode and the separation membrane are laminated. The fixing member includes an electrode assembly having a pattern shape with a large number of openings.

5. In an electrode assembly in which electrodes and separation membranes are alternately laminated, In one direction of the electrode assembly, the separation membrane has a structure longer than the electrode, whereby the separation membrane includes an extension portion protruding beyond the end of the electrode. Among the plurality of separation membranes included in the electrode assembly, a fixing member is formed to fix between the extension portions of the adjacent separation membranes along the direction in which the electrode and the separation membrane are laminated. The electrode assembly has a side surface defined in the direction (Y direction) in which the electrode and the separation membrane are laminated. The fixing member is an electrode assembly formed by partially applying an adhesive along the lamination direction (Y direction).

6. Further including an electrode tab protruding from one end of the electrode, The electrode assembly according to claim 5, wherein the direction in which the electrode tab protrudes is the same as the electrical installation direction.

7. In an electrode assembly in which electrodes and separation membranes are alternately laminated, The separation membrane has a zigzag shape formed by bending a rectangular sheet, In one direction of the electrode assembly, the separation membrane has a structure longer than the electrode at the bent portion of the zigzag shape, so that the separation membrane includes an extension portion protruding beyond the end of the electrode. An electrode assembly in which a fixing member for fixing a part of the extension portion of the separation membrane is formed in the separation membrane included in the electrode assembly.

8. The electrode assembly according to claim 7, wherein a finished separation membrane is located outside the fixing member.

9. The fixing member has a web structure including at least one line constituting a plurality of line sections, The electrode assembly according to any one of claims 4 to 8, wherein the web structure includes at least one intersection formed by two or more line sections.

10. The electrode assembly according to claim 9, wherein the line width of the lines of the web structure is 20 to 100 μm.

11. The electrode assembly according to claim 9, wherein the interval between adjacent lines of the web structure is 100 to 800 μm.

12. The electrode assembly according to any one of claims 5 to 8, wherein the fixing member includes a pattern shape having a large number of openings.

13. The electrode assembly has a side surface defined in the direction (Y direction) in which the electrode and the separation membrane are laminated, The electrode assembly according to claim 7 or 8, wherein the fixing member is formed by partially applying an adhesive along the lamination direction (Y direction).

14. Further including an electrode tab protruding from one end of the electrode, The electrode assembly according to claim 13, wherein the direction in which the electrode tab protrudes is the same as the electrical installation direction.

15. The separation membrane has long sides facing each other and short sides facing each other, The electrode assembly according to any one of claims 1 to 8, wherein the fixing member is formed on the long side of the separation membrane.

16. The electrode assembly according to any one of claims 1 to 8, wherein the fixing member is formed to cover 70 to 80% of one side surface of the electrode assembly.

17. The electrode assembly according to any one of claims 1 to 8, wherein the thickness of the fixing member is 100 to 600 μm.

18. The electrode assembly according to any one of claims 1 to 8, wherein the fixing member covers the extension portion of the separation membrane, and the height of the fixing member is the same as the height of the electrode assembly.

19. The fixing member includes an adhesive, and the electrode assembly according to any one of claims 1 to 8.

20. A battery cell including the electrode assembly according to any one of claims 1 to 8.

21. The electrode includes a positive electrode and a negative electrode, The electrode assembly according to any one of claims 1 to 8, wherein an end of the positive electrode is separated from the fixing member.

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