KR102622632B1 - Electrode assembly and battery cell including same - Google Patents

Abstract

An electrode assembly according to an embodiment of the present invention is an electrode assembly in which electrodes and separator sheets are alternately stacked, wherein the electrode includes a first electrode and a second electrode, and the separator sheet is formed by folding at least twice. It has a zigzag shape, the length of the second electrode is smaller than the length of the first electrode, and an adhesive member is positioned between either side of the electrode assembly and the second electrode.

Description

Electrode assembly and battery cell including same {ELECTRODE ASSEMBLY AND BATTERY CELL INCLUDING SAME}

The present invention relates to an electrode assembly and a battery cell including the same, and more specifically, to an electrode assembly in which electrodes and separator sheets are alternately stacked in a Z-folding manner, and a battery cell including the same, wherein the electrode is moved from its original position. The present invention relates to an electrode assembly with improved stiffness and a battery cell including the same, even though the adhesion of the separator sheet itself is low.

Generally, types of secondary batteries include nickel cadmium batteries, nickel hydrogen batteries, lithium ion batteries, and lithium ion polymer batteries. These secondary batteries are used not only for small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, Portable Game Devices, Power Tools, and E-bikes, but also for large products requiring high output such as electric vehicles and hybrid vehicles, as well as for surplus power generation. It is also applied and used in power storage devices that store power or renewable energy and backup power storage devices.

To manufacture such a secondary battery, an electrode active material slurry is first applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, and these are stacked on both sides of a separator to form an electrode assembly of a predetermined shape. Then, the electrode assembly is stored in the battery case, and the electrolyte is injected and sealed.

Electrode assemblies are classified into various types. For example, the simple stack type is to simply stack the anode, separator, and cathode by alternating them instead of manufacturing the unit cell. First, the unit cell is manufactured using the anode, separator, and cathode, and then these unit cells are Lamination & Stack Type (L&S), where multiple unit cells are spaced apart and attached to one side of a separator sheet that is long on one side, and the separator sheet is repeatedly folded from one end in the same direction. Type (S&F, Stack & Folding Type), a plurality of electrodes or unit cells are alternately attached to one side and the other side of a separator sheet that is long on one side, and the separator sheet is folded in a specific direction from one end and then folded in the opposite direction. There is a Z-Folding Type that repeats the method alternately. Among these, the Z-folding type has been frequently used recently due to its high degree of alignment and impregnation with electrolyte.

However, in the past, a separate laminating process was not performed after stacking the electrode and the separator sheet in this Z-folding type, so the electrode and the separator sheet were not adhered to each other, causing the electrode to deviate from its original position and the stiffness of the electrode assembly to decrease. ), there was a problem of deterioration. To solve this problem, a separate laminating process was performed after stacking the electrodes and separator sheets. However, since the overall thickness of the laminate with the electrodes and separator sheets has increased, heat is not transmitted to the inside of the laminate, resulting in poor adhesion. There was a problem with deterioration. These problems tended to worsen depending on the material of the separator sheet. For example, when the adhesive strength of the separator sheet itself is low, the problems described above become more severe.

Accordingly, there is a need to develop a Z-folding electrode assembly and a battery cell including the same that prevent the electrode from being moved out of position and have improved stiffness of the electrode assembly even if the adhesive force of the separator sheet itself is low.

The problem to be solved by the present invention is an electrode assembly in which electrodes and separator sheets are alternately stacked in a Z-folding manner, and a battery cell including the same. An electrode assembly with improved stiffness, even if low, and a battery cell including the same are provided.

The problem to be solved by the present invention is not limited to the above-mentioned problems, and problems not mentioned can be clearly understood by those skilled in the art from this specification and the attached drawings. .

An electrode assembly according to an embodiment of the present invention is an electrode assembly in which electrodes and separator sheets are alternately stacked, wherein the electrode includes a first electrode and a second electrode, and the separator sheet is formed by folding at least twice. It has a zigzag shape, the length of the second electrode is smaller than the length of the first electrode, and an adhesive member is positioned between either side of the electrode assembly and the second electrode.

The adhesive member is located between a separator sheet in contact with the upper surface of the second electrode and a separator sheet in contact with the lower surface of the second electrode, and the adhesive member is located on the side surrounded by the separator sheet among both sides of the second electrode. It may be located between the opposite side and the outer surface of the electrode assembly.

The first electrode and the second electrode include the side opposite to the side surrounded by the separator sheet among both sides of the first electrode and the side surrounded by the separator sheet among both sides of the second electrode. It may be biasedly aligned on one side of the outer surface of the assembly.

Among both sides of the adhesive member, one side facing one end of the second electrode may be spaced apart from the second electrode.

Among both sides of the adhesive member, a side opposite to one side facing one end of the second electrode may be arranged parallel to the outer surface of the electrode assembly.

Among both sides of the second electrode, the side surrounded by the separator sheet may be in contact with the separator sheet, and the side surrounded by the separator sheet among both sides of the first electrode may be in contact with the separator sheet.

Among both sides of the first electrode, the side opposite to the side surrounded by the separator sheet may be located on the same vertical line as the outer surface of the electrode assembly.

Adhesion between the electrode and the separator sheet may be 0 gf/mm or more and 0.05 gf/mm or less.

One end of the separator sheet may extend along the outer surface of the electrode assembly.

One end of the separator sheet may cover the entire outer surface of the electrode assembly.

It may further include a wrapping member surrounding the outer surface of the electrode assembly.

The wrapping member includes a first wrapping member and a second wrapping member, and the first wrapping member has a side opposite to the side surrounded by the separator sheet among both sides of the first electrode on the outer surface of the electrode assembly. The second wrapping member may surround a portion of the outer surface of the electrode assembly where a side opposite to one side facing one end of the second electrode is located among both sides of the adhesive member.

The first wrapping member may extend along one of the upper and lower surfaces of the electrode assembly, and the second wrapping member may extend along the other one of the upper and lower surfaces of the electrode assembly.

The wrapping member may be made of at least one of a hot-melt film and an adhesive tape.

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

According to embodiments, the present invention includes an electrode assembly in which electrodes and separator sheets are alternately stacked in a Z-folding manner, and an adhesive member is positioned between an electrode positioned between the separator sheets and an outer surface of the electrode assembly, and the same. As a battery cell, the electrode can be prevented from being moved out of position, and the stiffness of the electrode assembly can be improved even if the adhesive force of the separator sheet itself is low.

The effects of the present invention are not limited to the effects described above, and effects not mentioned can be clearly understood by those skilled in the art from this specification and the attached drawings.

1 is a diagram showing a final electrode assembly according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the electrode assembly taken along the A-A' axis of FIG. 1.
3 and 4 are cross-sectional views of an electrode assembly according to another embodiment of the present invention.
Figure 5 is a cross-sectional view of an electrode assembly according to a comparative example.
Figure 6 is a diagram showing an experimental example of measuring the stiffness of an electrode assembly.

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 regions. And in the drawings, for convenience of explanation, the thicknesses of some layers and regions are exaggerated.

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

In addition, throughout the specification, when referring to “on a plane,” this means when the target portion 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.

Below, an electrode assembly according to an embodiment of the present invention will be described. However, the description here will be based on a partial cross-section of the electrode assembly, but it is not necessarily limited to this, and the same or similar content may be explained in other cross-sections.

1 is a diagram showing a final electrode assembly according to an embodiment of the present invention. Figure 2 is a cross-sectional view of the electrode assembly taken along the A-A' axis of Figure 1.

Referring to Figures 1 and 2, the final electrode assembly 100 according to this embodiment may have a structure in which a fixing tape 300 is attached to the outer surface of the electrode assembly 200. Accordingly, the final electrode assembly 100 can maintain the stacking alignment between the first electrode 210, the second electrode 220, and the separator sheet 230 included in the electrode assembly 200. However, it is not limited to this, and the fixing tape 300 is omitted from the final electrode assembly 100 or is replaced with another member to form the first electrode 210, the second electrode 220, and the separator sheet 230. The stacking alignment between the stacks can be maintained.

In addition, the final electrode assembly 100 includes an electrode lead 400 to which electrode tabs extending from a plurality of first electrodes 210 and a plurality of second electrodes 220 included in the electrode assembly 200 are joined. can do. For example, as shown in FIG. 1, the electrode leads 400 may extend to both ends of the electrode assembly 200, respectively, and the electrode leads 400 may correspond to the polarity of the first electrode 210 and the second electrode 220. Depending on the lead, it can be classified into a positive lead or a negative lead. However, the position of the electrode lead 400 is not limited to this, and unlike FIG. 1, it may extend together at one end of the electrode assembly 200.

Additionally, the final electrode assembly 100 may include a lead film 500 located above and below the electrode lead 400. Here, as the final electrode assembly 100 is mounted on the battery case (not shown), the lead film 500 is sealed by a sealing portion (not shown) along with the outer periphery of the battery case (not shown). You can.

Referring to FIGS. 1 and 2 , the electrode assembly 200 according to an embodiment of the present invention may be an electrode assembly in which electrodes 210 and 220 and separator sheets 230 are alternately stacked.

The electrodes 210 and 220 may include a first electrode 210 and a second electrode 220. Here, the first electrode 210 and the second electrode 220 may include electrode active materials having different polarities. That is, the first electrode 210 and the second electrode 220 may be electrodes having different polarities. For example, if the first electrode 210 is an anode, the second electrode 220 may be a cathode. As another example, if the first electrode 210 is a cathode, the second electrode 220 may be an anode.

Additionally, the length of the second electrode 220 may be shorter than the length of the first electrode 210. In other words, the length of the first electrode 210 may be longer than the length of the second electrode 220. As shown in FIG. 2, the first electrode 210 and the second electrode 220 have different lengths along the first longitudinal direction L1, so that the first electrode 210 and the second electrode 220 There may be a difference in length between them. Accordingly, a tolerance d may be formed between the second electrode 220 and the outer surface of the electrode assembly 200. Here, the first longitudinal direction L1 may be the height direction or the longitudinal direction of the electrode assembly 200.

The separator sheet 230 may have a zigzag shape formed by folding at least twice. More specifically, as shown in FIG. 2, the separator sheet 230 may be folded in a direction to cover the first electrode 210 in a state in which the first electrode 210 is stacked. Additionally, while the second electrode 220 is stacked on the separator sheet 230 covering the first electrode 210, it can be folded in a direction to cover the second electrode 220. Thereafter, while the first electrode 210 is stacked on the separator sheet 230 covering the second electrode 220, it may be folded in a direction to cover the first electrode 210. That is, the electrode assembly 200 may be formed by repeatedly stacking the first electrode 210 or the second electrode 220 and folding the separator sheet 230.

Referring to FIG. 2, the first electrode 210 and the second electrode 220 are connected to the side opposite to the side surrounded by the separator sheet 230 among both sides of the first electrode 210 and the second electrode 220. ) of both sides, the side surrounded by the separator sheet 230 may be biasedly aligned to one side of the outer side of the electrode assembly 200. In other words, within the zigzag-shaped structure formed by folding the separator sheet 230, one end of the first electrode 210 and one end of the second electrode 220 are inclined to one side of the electrode assembly 200. It may be arranged to hit. That is, in the electrode assembly 200 according to this embodiment, the first electrode 210 and the second electrode 220 are not aligned based on the center of the electrode assembly 200, but are aligned on one side of the electrode assembly 200. It may be sorted based on .

Accordingly, in this embodiment, the adhesive member positioned between the second electrode 220 and the outer surface of the electrode assembly 200, which will be described later, prevents the second electrode 220 from being twisted within the separator sheet 230. The area of (250) can be larger.

In addition, the side surrounded by the separator sheet 230 among both sides of the second electrode 220 is in contact with the separator sheet 230, and the side surrounded by the separator sheet among both sides of the first electrode 210 is in contact with the separator sheet 230. It can be in contact with the sheet 230. Here, the meaning that the side of the first electrode 210 or the second electrode 220 and the separator sheet 230 are in contact means that the separator sheet 230 is in contact with the side of the first electrode 210 or the second electrode 220. It may mean that the separator sheet 230 extends along or surrounds the side of the first electrode 210 or the second electrode 220.

Accordingly, in this embodiment, it is possible to more effectively prevent the first electrode 210 and the second electrode 220 from being twisted within the separator sheet 230.

Additionally, among both sides of the first electrode 210, the side opposite to the side surrounded by the separator sheet 230 may be located on the same vertical line as the outer side of the electrode assembly 200. In other words, among both sides of the first electrode 210, the side opposite to the side surrounded by the separator sheet 230 may protrude toward the outer surface of the electrode assembly 200 or may not be recessed.

Accordingly, in this embodiment, the separator sheet 230 located above the first electrode 210 and the separator sheet 230 located below the first electrode 210 can be prevented from being folded during the process. .

Referring to FIG. 2 , the adhesive member 250 is located between the second electrode 220 and the outer surface of the electrode assembly 200. In other words, the adhesive member 250 may be located within the tolerance d between the second electrode 220 and the outer surface of the electrode assembly 200. More specifically, the adhesive member 250 may be positioned between the separator sheet 230 in contact with the upper surface of the second electrode 220 and the separator sheet 230 in contact with the lower surface of the second electrode 220. Additionally, the adhesive member 250 may be positioned between the outer surface of the electrode assembly 200 and a side opposite to the side surrounded by the separator sheet 230 among both sides of the second electrode 220.

Accordingly, in this embodiment, the adhesive member 250 is located in the space formed between the second electrode 220 and the outer surface of the electrode assembly 200, and has a structure that improves space efficiency, while the electrode 210 , The stiffness of the electrode assembly 200 can be improved by supplementing the adhesive force between the 220 and the separator 230.

Additionally, one side of both sides of the adhesive member 250 that faces the second electrode 220 and one end may be spaced apart from the second electrode 220. In other words, the side adjacent to the second electrode 220 among both sides of the adhesive member 250 may not be in contact with the second electrode 220.

Accordingly, in this embodiment, the adhesive member 250 is not in contact with the second electrode 220, so the adhesive material included in the adhesive member 250 is not in contact with the first electrode 210 and the second electrode 220. It is possible to prevent interference with the movement path of lithium ions formed in between. At this time, the second electrode 220 may be an anode, and the movement of lithium ions may be determined depending on the location of the anode, which is generally smaller in size than the cathode. Here, the separation distance (s) between one end of the second electrode 220 facing each other and one side of the adhesive member 250 may be at least 0.5 mm or more, preferably 0.6 mm or more, and more preferably 1 mm or more. there is. The reason for this is that, as a method of forming the adhesive member 250, the adhesive line width applied by the dispenser is about 0.4 to 0.6 mm. If these conditions are met, adhesive may be applied without the adhesive member 250 interfering with the anode side. Also, since adhesive can become a foreign substance, it is necessary to avoid applying too much.

Additionally, among both sides of the adhesive member 250, the side opposite to one side facing one end of the second electrode 220 may be arranged parallel to the outer surface of the electrode assembly 200. In other words, of both sides of the adhesive member 250, the side opposite to one side facing one end of the second electrode 220 may not protrude or be recessed relative to the outer surface of the electrode assembly 200. .

Accordingly, in this embodiment, while maximizing the area of the adhesive member 250, the separator sheet 230 located above the second electrode 220 and the separator sheet located below the second electrode 220 ( 230) can more effectively prevent folding during the process.

As an example, the adhesive member 250 may be made of an adhesive material containing one or more components selected from the group consisting of olefin, acrylate, urethane, ester, amide, vinyl acetate, and rubber-based polymer. However, it is not limited to this, and any material that can adhere between the electrodes 210 and 220 and the separator sheet 230 can be included in the present embodiment.

Additionally, the adhesive member 250 may be preferably applied uniformly to the tolerance d formed between the second electrode 220 and the outer surface of the electrode assembly 200. However, if the adhesive member 250 is applied to the entire surface of the tolerance d formed between the second electrode 220 and the outer surface of the electrode assembly 200, the amount of adhesive applied may be excessively large. In this case, the adhesive may flow to the outside of the separator sheet 230 and contaminate other parts, and the function of generating power when the secondary battery is manufactured may not function smoothly.

On the other hand, if the amount of adhesive applied is excessively small, the electrodes 210 and 220 are still not fixed to the separator sheet 230 and may deviate from their original positions as the cell moves. That is, it may be desirable that the gap between the areas where the adhesive is applied is not excessively wide.

Accordingly, in this embodiment, the adhesive member 250 is applied in the form of a spot application or a line to the tolerance d formed between the second electrode 220 and the outer surface of the electrode assembly 200. It may be preferable to apply it using a line application method. For example, the diameter of a dot in the spot application method or the width of the line in the line application method may be 100 um or more and 800 um or less. However, the diameter of the dot in the spot application method or the width of the line in the line application method is not limited to the above-mentioned range, and can be adjusted to have an appropriate diameter or width as needed.

Here, spot application or line application of the adhesive member 250 may be performed pneumatically or piezoelectricly. However, it is not limited to this, and any method that can apply the adhesive to a local area can be included in the present embodiment.

In addition, the electrode assembly 200 of this embodiment includes the second electrode 220 and the electrode assembly ( Since the adhesive member 250 is formed between the outer surfaces of the electrodes 200, the electrodes 210 and 220 can be prevented from leaving their original positions, and the stiffness of the electrode assembly can be maintained high.

More specifically, the separator sheet 230 may be a cheap separator with relatively low adhesive force. As an example, the separator sheet 230 may be a Ceramic Coated Seperator (CCS) separator. However, the separator sheet 230 is not limited to this, and any separator having adhesive strength similar to that of the CCS separator can be included in the present embodiment.

Here, when using the separator sheet 230, the adhesive force between the electrodes 210 and 220 of this embodiment and the separator sheet 230 may be 0 gf/mm or more and 0.05 gf/mm or less. More specifically, the adhesive force between the electrodes 210 and 220 and the separator sheet 230 may be 0 gf/mm or more and 0.045 gf/mm or less. As an example, the adhesive force between the electrodes 210 and 220 and the separator sheet 230 may be 0 gf/mm or more and 0.04 gf/mm or less.

At this time, in the case of this embodiment, even if the adhesive force between the electrodes 210 and 220 and the separator sheet 230 is within the range described above, an adhesive member ( 250) is formed to supplement the adhesive force between the electrodes 210 and 220 and the separator sheet 230, prevent the electrodes 210 and 220 from being moved from their correct positions, and improve the stiffness of the electrode assembly. can be kept high. In addition, this embodiment has the advantage of improving economic efficiency by reducing costs because the separator sheet 230 with relatively low adhesive force can be used.

Additionally, in this embodiment, there is no need to perform a laminating process through the adhesive member 250 as in the prior art, thereby reducing the defect rate in the process caused by high heat and pressure. And, since the laminator can be removed, the volume of the manufacturing device can be reduced and the manufacturing process can be simplified.

3 and 4 are cross-sectional views of an electrode assembly according to another embodiment of the present invention.

Referring to Figures 3 and 4, the electrode assemblies 201 and 202 according to another embodiment of the present invention can be described in most cases the same as the electrode assembly 200 described above, and hereinafter, the electrode assembly 200 I would like to explain only the parts that are different.

Referring to FIG. 3, in the electrode assembly 201 according to this embodiment, one end of the separator sheet 230 may extend along the outer surface of the electrode assembly 201. More specifically, one end of the separator sheet 230 may cover the entire outer surface of the electrode assembly 201. That is, one end of the separator sheet 230 may cover both sides and the upper and lower surfaces of the electrode assembly 201.

For example, as shown in FIG. 3, the end of the separator sheet 230 surrounding the outer surface of the electrode assembly 201 may be the end of the separator sheet 230 closest to the bottom surface. As another example, unlike FIG. 3, the end of the separator sheet 230 surrounding the outer surface of the electrode assembly 201 may be an end of the separator sheet 230 adjacent to the top of the electrode assembly 201.

Accordingly, in the electrode assembly 201 according to this embodiment, the separator sheet 230 surrounds the outer surface of the electrode assembly 201, thereby preventing the first electrode 210 from protruding to the outside. In addition, the separator sheet 230 surrounding the outer surface of the electrode assembly 201 can further improve the stiffness of the electrode assembly 201 and effectively prevent the separator sheet 230 from being folded. In addition, this embodiment can reduce costs and improve economic efficiency in that no separate members are required.

Referring to FIG. 4, the electrode assembly 202 according to this embodiment may further include a wrapping member 270 surrounding the outer surface of the electrode assembly 202. More specifically, the wrapping member 270 includes a first wrapping member and a second wrapping member. The first wrapping member may surround a portion of both sides of the first electrode 210 on the outer surface of the electrode assembly 202 where the side opposite to the side wrapped by the separator sheet 230 is located. The second wrapping member may wrap a portion of both sides of the adhesive member 250 on the outer surface of the electrode assembly 202 where the side opposite to one side facing one end of the second electrode 220 is located. That is, the first wrapping member can wrap one side of the electrode assembly 202, and the second wrapping member can wrap the other side of the electrode assembly 202.

In addition, the first wrapping member extends along one of the upper and lower surfaces of the electrode assembly 202, and the second wrapping member may extend along the other one of the upper and lower surfaces of the electrode assembly 202. . For example, as shown in FIG. 4 , one of the wrapping members 270 may extend along one side of the electrode assembly 202 and extend up to the top surface of the electrode assembly 202 . Additionally, the other wrapping member 270 may extend along the other side of the electrode assembly 202 and extend to the lower surface of the electrode assembly 202. However, the present invention is not limited to this, and the first wrapping member and the second wrapping member may be integrated with each other.

As an example, the wrapping member 270 may be a hot-melt film containing one or more components selected from the group consisting of olefin, acrylate, urethane, ester, amide, vinyl acetate, and rubber-based polymer. . As another example, the wrapping 270 member may be an adhesive tape. However, it is not limited to this, and any polymer material having elasticity and adhesive strength sufficient to cover the outer surface of the electrode assembly 202 may be included in the present embodiment.

Accordingly, in the electrode assembly 202 according to this embodiment, the wrapping member 270 surrounds the outer surface of the electrode assembly 201, thereby preventing the first electrode 210 from protruding to the outside. In addition, the wrapping member 270 surrounding the outer surface of the electrode assembly 201 can further improve the stiffness of the electrode assembly 201 and effectively prevent the separator sheet 230 from being folded.

Figure 5 is a cross-sectional view of an electrode assembly according to a comparative example.

Referring to FIG. 5 , the electrode assembly 20 according to the comparative example may have first electrodes 21 and second electrodes 22 alternately stacked between separators 23 . In the comparative example, due to the tolerance between the separator 23 and the electrodes 21 and 22, the end of the separator 23 may protrude outward with respect to the outer surface of the electrode assembly 20. Accordingly, the end of the separator 23 may be folded during the process, and there is a problem that a short circuit occurs when the separator 23 shrinks at high temperature.

In addition, in the case of the comparative example, no separate adhesive member was formed between the separator 23 and the electrodes 21 and 22, preventing the electrodes 210 and 220 from being positioned in the electrode assembly 20. To prevent this, a separator 23 with high adhesion must be used. However, in the case of the separator 23 with high adhesive strength, a relatively high cost is required as described above, so there is a problem that economic efficiency decreases as the cost increases.

In contrast, referring to FIGS. 1 to 4, the electrode assembly 200, 201, and 202 according to this embodiment has an adhesive member 250 between the second electrode 220 and the outer surface of the electrode assembly 200. There is an advantage in that the separator sheet 230 with relatively low adhesion can be used, while preventing the electrodes 210 and 220 from leaving their original positions and maintaining high stiffness of the electrode assembly. .

A battery cell according to another embodiment of the present invention includes the electrode assembly described above. The battery cell may include a battery case (not shown) that accommodates the above-described electrode assemblies 200, 201, and 202 along with an electrolyte solution. At this time, the electrode assemblies 200, 201, and 202 may be manufactured from the final electrode assembly 100 described above and accommodated in the battery case (not shown).

Here, the battery case (not shown) may be a laminated sheet including a resin layer and a metal layer. More specifically, the battery case (not shown) is made of a laminated sheet and may be composed of an outer resin layer forming the outermost layer, a barrier metal layer to prevent penetration of materials, and an inner resin layer for sealing.

Below, the content of the present invention will be described through more specific examples. However, the following examples are for illustrative purposes only, and the scope of the present invention is not limited thereto.

<Comparative example>

An electrode assembly having a zigzag shape was manufactured by stacking the separator sheets alternately in that order, the anode and the cathode, and the separator sheets were folded at least twice. Here, the separator sheet is a CCS (Ceramic Coated Seperator) separator. Additionally, the size of the electrode assembly is 510mm*97mm.

<Example>

In Comparative Example 1, the length of the positive electrode was smaller than the length of the negative electrode, and an adhesive was applied between the positive electrode and the outer surface of the electrode assembly to form an adhesive member. The electrode assembly was the same as Comparative Example 1. was manufactured.

<Experimental Example - Comparison of Stiffness>

Figure 6 is a diagram showing an experimental example of measuring the stiffness of an electrode assembly. As shown in Figure 6, after placing the center of the electrode assembly 200 on a 50 mm thick bar, the bending degree (L) of the electrode assembly 200 was measured based on the top of the bar, and the bending degree (L) was measured. The results are shown in Table 1.

Comparative example Example Bending degree of electrode assembly (L) 100cm 50cm

<Analysis of experiment results>

Referring to Table 1, as in the comparative example, when a separate adhesive member is not formed, it can be seen that both ends of the electrode assembly 200 are bent relatively much with respect to the center of the electrode assembly 200. In contrast, as in the embodiment, when an adhesive member to which adhesive is applied is formed between the positive electrode and the outer surface of the electrode assembly, both ends of the electrode assembly 200 are bent relatively little with respect to the center of the electrode assembly 200. You can check that it happens.

Accordingly, as in the embodiment, even in the case of an electrode assembly including a separator with relatively low adhesive strength, the stiffness of the electrode assembly is improved through the adhesive member in which adhesive is applied between the positive electrode and the outer surface of the electrode assembly. You can check that it is done.

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. It falls within the scope of invention rights.

100: final electrode assembly
200, 201, 202: electrode assembly
210: first electrode
220: second electrode
230: Separator sheet
250: Adhesion member
270: Lapping member
300: fixing member
400: electrode lead
500: lead film

Claims (15)

An electrode assembly in which electrodes and separator sheets are alternately stacked,
The electrode includes a first electrode and a second electrode,
The separator sheet has a zigzag shape formed by folding at least twice,
The length of the second electrode is smaller than the length of the first electrode,
An adhesive member is positioned between one of both sides of the electrode assembly and the second electrode,
The adhesive member is located between the outer surface of the electrode assembly and a side opposite to the side surrounded by the separator sheet among both sides of the second electrode. In paragraph 1:
The adhesive member is an electrode assembly positioned between a separator sheet in contact with the upper surface of the second electrode and a separator sheet in contact with the lower surface of the second electrode. In paragraph 1:
The first electrode and the second electrode include the side opposite to the side surrounded by the separator sheet among both sides of the first electrode and the side surrounded by the separator sheet among both sides of the second electrode. An electrode assembly that is biasedly aligned on one side of the outer surface of the assembly. In paragraph 3,
An electrode assembly wherein one side of both sides of the adhesive member, which faces one end of the second electrode, is spaced apart from the second electrode. In paragraph 4,
An electrode assembly wherein, among both sides of the adhesive member, a side opposite to one side facing one end of the second electrode is arranged in parallel with an outer surface of the electrode assembly. In paragraph 3,
Among both sides of the second electrode, the side surrounded by the separator sheet is in contact with the separator sheet,
Of the two sides of the first electrode, the side surrounded by the separator sheet is in contact with the separator sheet. In paragraph 6:
Of the two sides of the first electrode, the side opposite to the side surrounded by the separator sheet is located on the same vertical line as the outer surface of the electrode assembly. In paragraph 1:
An electrode assembly wherein the adhesive force between the electrode and the separator sheet is 0 gf/mm or more and 0.05 gf/mm or less. In paragraph 1:
An electrode assembly wherein one end of the separator sheet extends along an outer surface of the electrode assembly. In paragraph 9:
An electrode assembly where one end of the separator sheet surrounds the entire outer surface of the electrode assembly. In paragraph 1:
An electrode assembly further comprising a wrapping member surrounding an outer surface of the electrode assembly. In paragraph 11:
The wrapping member includes a first wrapping member and a second wrapping member,
The first wrapping member surrounds a portion of both sides of the first electrode on the outer surface of the electrode assembly where the side opposite to the side surrounded by the separator sheet is located,
The second wrapping member is an electrode assembly that surrounds a portion of the outer surface of the electrode assembly where a side opposite to one side facing one end of the second electrode is located among both sides of the adhesive member. In paragraph 12:
The first wrapping member extends along one of the upper and lower surfaces of the electrode assembly,
The second wrapping member is an electrode assembly extending along the remaining one of the upper and lower surfaces of the electrode assembly. In paragraph 11:
An electrode assembly wherein the wrapping member is made of at least one of a hot-melt film and an adhesive tape. A battery cell comprising the electrode assembly of claim 1.