KR20240064438A - Pouch and method for manufacturing the pouch cell including the same - Google Patents

Abstract

The present invention is a pouch that can reduce the possibility of process problems or product defects caused by electrode leads and lead films in the sealing process, and can efficiently improve the sealability of the pouch in the sealing process, and a pouch cell containing the same. It relates to a manufacturing method.
A pouch formed from a pouch film including an inner layer having heat sealability according to the present invention includes a cup portion formed in an indented shape to accommodate an electrode assembly in the form of a stack of electrodes and a separator, and a portion of an electrode lead connected to the electrode assembly. a lead accommodating portion formed in an indented shape at a position corresponding to one end of the cup portion to receive the electrode; The thickness of the lead (Tl), the thickness of the lead film (Tf), the depth of the lead receiving portion (Ta), and the thickness of the inner layer (Tp) may satisfy equation (1).
Tl/2 + (Tf + Tp) x 0.58 ≤ Ta ≤ Tl/2 + (Tf + Tp) x 0.68 ...(1)

Description

Pouch and method of manufacturing pouch cell including same {POUCH AND METHOD FOR MANUFACTURING THE POUCH CELL INCLUDING THE SAME}

The present invention relates to a pouch and a method of manufacturing a pouch cell including the same. More specifically, it relates to a pouch used for manufacturing a pouch cell capable of charging and discharging and a method of manufacturing a pouch cell including the same.

In recent years, the price of energy sources has risen due to the depletion of fossil fuels, and interest in environmental pollution has increased, and the demand for eco-friendly alternative energy sources has become an essential factor for future life. Accordingly, research continues on various power production technologies such as solar power, wind power, and tidal power, and there is also great interest in power storage devices such as batteries to use the electric energy produced in this way more efficiently.

Moreover, as technology development and demand for electronic mobile devices and electric vehicles using batteries increase, the demand for batteries as an energy source is rapidly increasing, and accordingly, much research is being conducted on batteries that can meet various needs. there is.

Batteries that store electrical energy can generally be divided into primary batteries and secondary batteries. Primary batteries are disposable consumable batteries, while secondary batteries are rechargeable batteries manufactured using materials in which oxidation and reduction processes between current and materials can be repeated. In other words, when a reduction reaction is performed on a material by current, the power is charged, and when an oxidation reaction is performed on the material, the power is discharged. As this charging and discharging is repeatedly performed, electricity is generated.

Depending on the shape of the battery case, the secondary battery may be a cylindrical cell in which the wound electrode assembly is housed in a cylindrical metal can, a square cell in which the electrode assembly is housed in a square metal can, or a pouch-type case in which the electrode assembly is made of a metal laminated sheet. It can be classified as a pouch cell built in, etc.

Among these, the pouch cell may be an electrode assembly in which an anode, a cathode, and a separator are stacked together and placed inside the pouch. In general, pouches can be manufactured by molding a pouch film with a punch or the like. At this time, a space in which the electrode assembly is accommodated may be formed in the pouch.

Meanwhile, an electrode lead may be connected to the electrode assembly for electrical connection to the outside, and a lead film may be attached to the electrode lead for insulation and adhesion. Since the electrode lead and a portion of the lead film are disposed inside the pouch, there is a possibility that the electrode assembly may be accommodated in the pouch while its position is misaligned due to the electrode lead and lead film during the pouch sealing process.

Accordingly, there is a need for a method of manufacturing a pouch and a pouch cell containing the pouch that can have the desired performance and at the same time reduce the possibility of process problems or product defects caused by electrode leads and lead films in the pouch sealing process.

The present invention was created to solve the above problems, and the object of the present invention is to achieve the target performance while reducing the possibility of process problems or product defects caused by electrode leads and lead films in the sealing process. , to provide a method of manufacturing a pouch and a pouch cell containing the pouch that can efficiently improve the sealability of the pouch in the sealing process.

A pouch formed from a pouch film including an inner layer having heat sealability according to the present invention includes a cup portion formed in an indented shape to accommodate an electrode assembly in the form of a stack of electrodes and a separator, and a portion of an electrode lead connected to the electrode assembly. a lead accommodating portion formed in an indented shape at a position corresponding to one end of the cup portion to receive the electrode; The thickness of the lead (Tl), the thickness of the lead film (Tf), the depth of the lead receiving portion (Ta), and the thickness of the inner layer (Tp) may satisfy equation (1).

Tl/2 + (Tf + Tp) x 0.58 ≤ Ta ≤ Tl/2 + (Tf + Tp) x 0.68 ...(1)

In the pouch, the thickness of the lead film (Tf), the depth of the film receiving portion (Tb), and the thickness of the inner layer (Tp) may satisfy equation (2).

(Tf + Tp) x 0.58 ≤ Tb ≤ (Tf + Tp) x 0.68 ...(2)

In the pouch, the width of the electrode lead (Wl), the thickness of the lead film (Tf), the width of the lead receiving portion (Wa), and the thickness of the inner layer (Tp) may satisfy equation (3).

Wl + 2 x (Tf + Tp) x 0.58 ≤ Wa ≤ Wl + 2 x (Tf + Tp) x 0.68 ...(3)

The depth (Ta) of the lead accommodating portion may have a value greater than the depth (Tb) of the film accommodating portion.

The width (Wl) of the lead accommodating portion may have a value smaller than the width (Wb) of the film accommodating portion.

The pouch may be disposed on one side of the first accommodating part so that the cup part and the first accommodating part in which the cup part, the lead accommodating part, and the film accommodating part are formed, and includes a second accommodating part in which the lead accommodating part and the film accommodating part are formed. can do.

The pouch cell manufacturing method according to the present invention includes the steps of (a) forming a cup portion with an indented shape to accommodate the electrode assembly in a pouch film including an inner layer having thermal adhesiveness, (b) attaching the electrode assembly to one end of the cup portion. forming a lead receiving portion of an indented shape to accommodate a portion of the connected electrode lead, (c) forming a film receiving portion of an indented shape to accommodate a portion of the lead film surrounding the electrode lead on both sides of the lead receiving portion, and ( d) sealing the edge of the molded pouch film, wherein in step (d), the thickness of the lead film and the thickness of the inner layer are changed, and the sum of the thickness of the lead film and the thickness of the inner layer after the change (Tf + Tp) ' can satisfy the equation (4) below.

(Tf + Tp) x 0.58 ≤ (Tf + Tp)' ≤ (Tf + Tp) x 0.68 ...(4)

In the pouch cell manufacturing method, in step (d), the lead film and inner layer may partially melt due to heat, thereby reducing the thickness.

Steps (a), (b) and (c) may proceed simultaneously.

A pouch formed from a pouch film including an inner layer having heat sealability according to the present invention includes a cup portion formed in an indented shape to accommodate an electrode assembly in the form of a stack of electrodes and a separator, and a portion of an electrode lead connected to the electrode assembly. a lead accommodating portion formed in an indented shape at a position corresponding to one end of the cup portion to receive the electrode; The thickness of the lead (Tl), the thickness of the lead film (Tf), the depth of the lead receiving portion (Ta), and the thickness of the inner layer (Tp) may satisfy equation (1).

Tl/2 + (Tf + Tp) x 0.58 ≤ Ta ≤ Tl/2 + (Tf + Tp) x 0.68 ...(1)

Accordingly, it is possible to reduce cases where the position at which the electrode assembly is inserted into the pouch is incorrect during the pouch cell manufacturing process.

Additionally, sealing performance can be improved by reducing the gap between the pouch, the electrode lead, and the lead film.

In addition, it is possible to prevent the lead film from being damaged during the sealing process and the insulation performance to deteriorate.

Additionally, it is possible to have the effects described above while maintaining the target performance.

Additionally, the above-mentioned effects can reduce the incidence of defective pouch cells.

The effects according to the present invention are not limited by the contents exemplified above, and further various effects may be included within the present specification.

Figure 1 is a perspective view schematically showing a pouch according to Example 1 of the present invention.
Figure 2 is a perspective view schematically showing a pouch cell manufactured from a pouch according to Example 1 of the present invention.
Figure 3 is a cross-sectional view schematically showing a cross-section of the pouch cell of Figure 2 cut along C-C'.
Figure 4 is a cross-sectional view schematically showing a cross-section of the pouch cell of Figure 2 cut along DD'.
Figure 5 is a cross-sectional view schematically showing a cross-section of the pouch of Figure 1 cut along A-A'.
Figure 6 is a cross-sectional view schematically showing a cross-section of the pouch of Figure 1 cut along B-B'.
Figure 7 is a perspective view schematically showing a pouch according to Example 2 of the present invention.
Figure 8 is a perspective view schematically showing a pouch cell manufactured from a pouch according to Example 2 of the present invention.
FIG. 9 is a cross-sectional view schematically showing a cross-section of the pouch cell of FIG. 8 cut along G-G'.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

In order to clearly explain the present invention, detailed descriptions of parts unrelated to the description or related known technologies that may unnecessarily obscure the gist of the present invention have been omitted, and reference signs are added to components in each drawing in this specification. In this regard, identical or similar reference numerals are assigned to identical or similar components throughout the specification.

In addition, terms or words used in this specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

Example 1

Figure 1 is a perspective view schematically showing a pouch 100 according to Example 1 of the present invention. In addition, Figure 1 shows an electrode assembly (E), an electrode lead (L), and a lead film (F) accommodated inside the pouch 100 according to Example 1 of the present invention.

The pouch 100 can be used to manufacture the pouch cell 10. Specifically, the electrode assembly (E) may be accommodated inside the pouch 100, and a portion of the electrode lead (L) and lead film (F) may be accommodated. Referring to FIG. 1, the electrode lead (L) may be connected to the electrode assembly (E), and the lead film (F) may cover a portion of the electrode lead (L).

As an example of a configuration for efficiently accommodating the electrode assembly (E), the electrode lead (L), and the lead film (F) inside the pouch 100, the pouch 100 according to Example 1 of the present invention has a cup portion ( 110), a lead receiving portion 120, and a film receiving portion 130.

Referring to FIG. 1, the cup portion 110 of the pouch 100 may be formed in a recessed shape to accommodate an electrode assembly (E) in the form of a stacked electrode and a separator. Here, the electrode may include a cathode and an anode. Additionally, a separator may be disposed between the cathode and the anode to block physical contact between the cathode and the anode.

Meanwhile, the depth or width of the cup portion 110 may vary depending on the shape of the electrode assembly (E). Additionally, the shape into which the cup portion 110 is indented may also vary depending on the shape of the electrode assembly (E).

The lead receiving portion 120 of the pouch 100 may be formed in a recessed shape at a position corresponding to one end of the cup portion 110 to accommodate a portion of the electrode lead (L) connected to the electrode assembly (E). Specifically, the lid receiving portion 120 may be formed to extend from one end of the cup portion 110 to the outermost edge of the pouch 100. This is because the electrode lead (L) may be arranged in a form extending from the electrode assembly (E) to the outside of the pouch (100).

The electrode lead (L) may serve to electrically connect the electrode assembly (E) to the outside. Specifically, the electrode lead (L) may be electrically connected to the electrode tab of the electrode assembly (E). Here, the electrode lead (L) can be a conductor, and metal can generally be used. Additionally, since the electrode lead L generally has a substantially plate shape, the lead receiving portion 120 may be indented to have a substantially plate shape.

The film receiving portion 130 of the pouch 100 may be formed in a recessed shape on both sides of the lead receiving portion 120 to accommodate a portion of the lead film (F) surrounding the electrode lead (L).

The lead film (F) may serve to insulate the pouch 100 and the electrode lead (L) from each other and at the same time serve to bond and seal the pouch 100 and the electrode lead (L). Accordingly, the lead film F may include an insulating material. Preferably, the lead film (F) may be made of an insulating material.

Since the lead film (F) surrounds a portion of the electrode lead (L), the film accommodating portion 130 may be formed in a portion of the lead accommodating portion 120 based on the longitudinal direction. Preferably, the film receiving portion 130 may be formed to extend a certain length from the outermost portion of the pouch 100 toward the cup portion 110. Additionally, since the lead film F has a substantially rectangular cross-section, the film receiving portion 130 may be indented to have a substantially plate shape.

The conventional pouch included only the cup portion, and the sealing process was performed with the electrode lead (L) and lead film (F) placed on a flat part of the pouch. Accordingly, there was a problem that the electrode assembly (E) was placed in a distorted state when the electrode assembly (E) was inserted, or the lead film (F) was damaged and the insulation was broken. However, since the pouch 100 according to Example 1 of the present invention includes a lead receiving portion 120 and a film receiving portion 130 in addition to the cup portion 110, the parts may be distorted or the lead film (F) may be damaged during the sealing process. Problems such as broken insulation can be prevented. Therefore, the accuracy of the process can be improved.

Meanwhile, the pouch 100 may be manufactured through a process in which a portion of the pouch film is molded. At this time, the pouch film forming device can form the pouch film by pressing it with a punch or the like. However, this is just one example and the pouch film can be formed through other methods.

When the pouch film is molded, the pouch 100 in which the previously described cup portion 110, lead receiving portion 120, and film receiving portion 130 are formed can be manufactured.

Referring to FIG. 1, the pouch 100 according to Example 1 of the present invention may include two parts in which a cup portion 110, a lead receiving portion 120, and a film receiving portion 130 are formed. Preferably, the pouch film can be molded so that the shapes of the two parts are plane symmetrical to each other. Additionally, the two parts can be folded to face each other based on a borderline that folds toward the electrode assembly (E) accommodated inside the pouch 100.

After the electrode assembly (E), electrode lead (L), and lead film (F) are accommodated inside the pouch 100, the edge of the pouch 100 may be sealed through a sealing process. In the sealing process, the edge of the pouch 100 may be sealed while the sealing device applies heat and pressure to the edge of the pouch 100.

Meanwhile, the portion of the pouch 100 other than the portion where the cup portion 110, the lid accommodating portion 120, and the film accommodating portion 130 are formed is a portion that is not molded in the process of forming the pouch 100 from the pouch film. It can be. A portion of the unmolded portion of the pouch 100 may be removed after a degassing process.

The form of the pouch cell 10 manufactured with the pouch 100 according to Example 1 of the present invention described above will be described in detail as follows.

Figure 2 is a perspective view schematically showing the pouch cell 10 manufactured from the pouch 100 according to Example 1 of the present invention, and Figure 3 shows the pouch cell 10 of Figure 2 cut along C-C'. This is a cross-sectional view schematically showing the cross-sectional view. In addition, FIG. 4 is a cross-sectional view schematically showing the pouch cell 10 of FIG. 2 cut along DD'.

Referring to FIG. 2, the pouch cell 10 according to Embodiment 1 of the present invention has a shape in which both sides are convexly formed by the cup portion 110 of the pouch 100 with respect to the electrode assembly (E) accommodated therein. You can have it. Additionally, a portion of the electrode lead (L) may protrude from both ends of the convex portion by the cup portion 110, and a portion of the lead film (F) disposed on both sides of the electrode lead (L) may protrude. A pair of electrode leads (L) and lead films (F) of the pouch cell 10 according to Example 1 of the present invention have a shape that protrudes in both directions. This is only an example, and the electrode lead (L) and the lead film (F) may both protrude in one direction.

Meanwhile, as described above, some parts of the pouch 100 that are not molded may be removed after a degassing process. Accordingly, in FIG. 2, it can be seen that the area of the unmolded portion of the pouch cell 10 is reduced compared to FIG. 1.

Referring to FIG. 3, the pouch cell 10 has an electrode assembly (E) disposed in the cup portion 110 of the pouch 100, and an electrode lead (L) connected to the electrode assembly (E) is attached to the outside of the pouch 100. It may be extended until. Additionally, the portion where the lead film F is disposed may be sealed by bonding the pouch 100 and the lead film F to each other when the edge of the pouch 100 is sealed.

Referring to FIG. 4, the electrode lead L is disposed in the lead receiving portion 120 at the edge of the pouch 100 corresponding to the portion where the electrode lead L and the lead film F are disposed, and the film A lead film (F) may be disposed in the receiving portion 130. At this time, it may be desirable for the electrode lead (L) and the lead film (F) to be sealed without an empty space between the lead film (F) and the pouch (100).

FIG. 5 is a cross-sectional view schematically showing a cross-section of the pouch 100 of FIG. 1 cut along A-A', and FIG. 6 is a cross-section of the pouch 100 of FIG. 1 cut along B-B'. This is a cross-sectional view schematically showing what it looks like.

As an example of a configuration for being disposed so that there is no empty space between the electrode lead (L) and the lead film (F) or between the lead film (F) and the pouch 100, the pouch 100 according to Example 1 of the present invention ), the thickness of the electrode lead (Tl), the thickness of the lead film (Tf), the depth of the lead receiving portion (Ta), and the thickness of the inner layer (Tp) may satisfy the equation (1) below.

Tl/2 + (Tf + Tp) x 0.58 ≤ Ta ≤ Tl/2 + (Tf + Tp) x 0.68 ...(1)

Additionally, the thickness of the lead film (Tf), the depth of the film receiving portion (Tb), and the thickness of the inner layer (Tp) may satisfy the equation (2) below.

(Tf + Tp) x 0.58 ≤ Tb ≤ (Tf + Tp) x 0.68 ...(2)

Here, the thickness of the lead film (Tf; see Figure 3) may refer to the thickness of the lead film (F) before the sealing process is performed, and the thickness of the inner layer (Tp; see Figure 6) may refer to the thickness of the unmolded portion of the pouch. (100) may refer to the thickness of the inner layer 101.

Referring to FIG. 5, half of the electrode lead (L) and the lead film (F) are disposed in the lead accommodating portion 120 based on the vertical direction of FIG. 5, so the theoretical depth (Ta) of the lead accommodating portion is the electrode The length may be equal to the sum of half the thickness of the lead (Tl; see FIG. 3) and the thickness of the lead film (Tf). Additionally, since the lead film (F) is disposed in the film receiving portion 130, the theoretical depth (Tb) of the film receiving portion may be equal to the thickness (Tf) of the lead film.

In relation to this, when the pouch 100 is compressed while applying heat to the edge portion of the pouch 100 in the sealing process, a portion of the inner layer 101 and the lead film F may be melted by the heat. Accordingly, the lead receiving portion 120 and the film receiving portion 130 of the pouch 100 may be formed to be smaller than the thickness of the components disposed therein. That is, the lead accommodating part 120 and the film accommodating part 130 may be formed at a depth different from the theoretical depth described above. Specifically, the lead accommodating portion 120 and the film accommodating portion 130 may be formed to have a depth reduced from the theoretical depth described above.

Below, the reason why a portion of the inner layer 101 and the lead film F melts due to the heat when heat is applied to the edge of the pouch 100 in the sealing process will be explained.

Referring to Figure 6, the pouch 100 can be classified into four layers. Specifically, the pouch 100 can be classified from the inside into an inner layer 101, a metal layer 102, an insulating layer 103, and an outer layer 104. Since the pouch 100 is manufactured by molding the pouch film, the pouch film may include the four layers described above.

The inner layer 101 of the pouch 100 must have insulation properties because it is in direct contact with the electrode assembly (E), and must have corrosion resistance because it is also in contact with the electrolyte solution. At this time, the inner layer 101 of the pouch 100 may include a sealant layer. In the sealing process, when heat is applied to the edge of the pouch 100 and pressure is applied, the sealant layers are bonded to each other, thereby sealing the pouch 100. The material forming the sealant layer can mainly be a polyolefin-based resin such as polypropylene (PP) or polyethylene (PE). Preferably, polypropylene (PP), which has excellent mechanical properties such as tensile strength, rigidity, surface hardness, wear resistance, heat resistance, and chemical properties such as corrosion resistance, can be mainly used to manufacture the sealant layer.

Meanwhile, the lead film (F) may also require insulating and thermally adhesive properties. Accordingly, the lead film (F) may be made of the same material as the sealant layer described above.

That is, since materials such as polypropylene (PP) can be melted by heat during the sealing process, a portion of the inner layer 101 and the lead film (F) are melted by heat. At this time, the portion melted by heat may serve to adhere the pouch 100 to each other or to adhere the pouch 100 and the lead film (F) to each other.

As described above, the lead accommodating portion 120 and the film accommodating portion 130 may be formed to a depth less than the theoretical depth because a portion of the inner layer 101 and the lead film F is melted by heat.

Hereinafter, a description will be given regarding the ratio at which the lead accommodating portion 120 and the film accommodating portion 130 can be reduced from the theoretical depth.

If the depth (Ta) of the lead receiving portion is smaller than “Tl/2 + (Tf + Tp) x 0.58”, it can be considered that the inner layer 101 or the lead film (F) is excessively melted. In this case, the thickness of the inner layer 101 or the lead film (F) may be excessively reduced during the sealing process, which may cause problems with insulation performance. If a problem occurs in the insulation performance of the pouch 100 and the lead film (F), additional problems such as short circuit may occur because insulation is not achieved between the pouch 100 and the electrode lead (L).

Additionally, if the inner layer 101 or the lead film F is excessively melted, a temporary adhesive area may be formed in a portion of the pouch 100 that is not sealed. The adhesive area may refer to a portion of the excessively melted inner layer 101 or a portion of the lead film F that is pushed out in a ball shape toward the inside of the pouch 100. This adhesive area has the disadvantage of being weak in durability, and there may be a risk that a chunk of the adhesive area may fall off due to an external impact and the insulation performance of that area may be broken.

Accordingly, the depth Ta of the lead receiving portion may be formed to be “Tl/2 + (Tf + Tp) x 0.58” or more.

Additionally, if the depth (Ta) of the lead receiving portion is formed to be greater than “Tl/2 + (Tf + Tp) In this case, there may be a concern that the sealing strength of the pouch 100 may be insufficient.

Insufficient sealing strength of the pouch 100 may mean that the sealing properties of the pouch 100 are insufficient. In this case, there is a risk that the electrolyte may leak out from the inside of the pouch 100, and there is also a possibility that the sealed portion may be damaged by gas generated inside the pouch 100.

Accordingly, the depth Ta of the lead receiving portion may be formed to be less than or equal to “Tl/2 + (Tf + Tp) x 0.68”.

As described above, in order to secure insulation and sealing strength, the depth (Tb) of the film receiving portion may also be formed to be "(Tf + Tp) x 0.58" or more and "(Tf + Tp) x 0.68" or less.

Meanwhile, the pouch 100 according to Example 1 of the present invention has the width of the electrode lead (Wl), the thickness of the lead film (Tf), the width of the lead receiving portion (Wa), and the thickness of the inner layer (Tp) as follows (3) The equation can be satisfied.

Wl + 2 x (Tf + Tp) x 0.58 ≤ Wa ≤ Wl + 2 x (Tf + Tp) x 0.68 ...(3)

Referring to FIG. 5, since the electrode lead L and the lead films F on both sides are disposed in the lead receiving portion 120 based on the width direction (horizontal direction in FIG. 5), the theoretical width of the lead receiving portion ( Wa) may be equal to the sum of twice the width (Wl) of the electrode lead and the thickness (Tf) of the lead film.

In relation to this, when the pouch 100 is compressed while applying heat to the edge portion of the pouch 100 in the sealing process, a portion of the inner layer 101 and the lead film F may be melted by the heat. Accordingly, the width Wa of the lead receiving portion of the pouch 100 may be formed to be smaller than the widths of the components disposed therein. That is, the lead receiving portion 120 may be formed to have a width different from the theoretical width described above.

As described above, the difference between the width Wa of the lead accommodating portion and the theoretical width may be set in consideration of the insulation and sealing strength between the pouch 100 and the lead film F. That is, in order to secure the insulation and sealing strength between the pouch 100 and the lead film (F), the width (Wa) of the lead receiving part is also "Wl + 2 ⅹ (Tf + Tp) x 0.58" or more, "Wl + 2 ⅹ ( It can be formed as Tf + Tp) x 0.68" or less.

Therefore, on the same principle as the depth of the lead accommodating part (Ta) and the depth of the film accommodating part (Tb), the width (Wa) of the lead accommodating part can satisfy the equation (3) below.

Wl + 2 ⅹ (Tf + Tp) x 0.58 ≤ Wa ≤ Wl + 2 ⅹ (Tf + Tp) x 0.68...(3)

Meanwhile, since the electrode lead (L) is additionally disposed in the lead accommodating part 120 compared to the film accommodating part 130, the depth (Ta) of the lead accommodating part may have a value greater than the depth (Tb) of the film accommodating part. there is.

In addition, since the film accommodating portion 130 is disposed with a lead film (F) extending and attached to both sides of the electrode lead (L), the width (Wa) of the lead accommodating portion has a value smaller than the width (Wb) of the film accommodating portion. You can.

Since the pouch 100 according to Example 1 of the present invention includes a pre-formed lead receiving portion 120 and a film receiving portion 130, the electrode assembly (E) is placed in the pouch 100 during the manufacturing process of the pouch cell 10. The degree to which the insertion position is distorted can be reduced. Additionally, sealing performance can be improved by reducing the gap occurring between the pouch 100 and the lead film (F), and it is possible to prevent the lead film (F) from being damaged during the sealing process and thus deteriorating insulation performance.

Meanwhile, the lead accommodating part 120 and the film accommodating part 130 may be formed to have a depth and width that are smaller than the theoretical depth and width. During the molding process of the pouch film, as the molded depth or width increases, the pouch film is stretched more, so the pouch 100 in that portion becomes thinner. Therefore, as the molded depth and width of the pouch film decrease, the thickness of the molded portion of the pouch 100 can be maintained close to the thickness of the pouch film. In this regard, the lead receiving portion 120 and the film receiving portion 130 of the pouch 100 according to Example 1 of the present invention may be formed with a depth and width that satisfy appropriate conditions. Accordingly, the pouch 100 secures insulation and sealing strength while at the same time reducing the thickness as much as possible through molding, thereby improving the performance of the final product, the pouch cell 10, and reducing defects.

Example 2

Figure 7 is a perspective view schematically showing a pouch 100' according to Example 2 of the present invention. In addition, Figure 8 is a perspective view schematically showing the pouch cell 10' manufactured from the pouch 100' according to Example 2 of the present invention, and Figure 9 shows the pouch cell 10' of Figure 8 as G- This is a cross-sectional view schematically showing a cross-section cut along G'.

Specifically, the pouch 100' according to Example 2 of the present invention differs from the pouch 100 of Example 1 in the number, formation position, and formation depth of the cup portion 110. In addition, the pouch cell 10' according to Example 2 of the present invention is different from the pouch cell 10 of Example 1 in that the convex protruding portion is formed only on one side by the electrode assembly E disposed therein. This exists.

Hereinafter, a detailed description of the same configuration as that of the pouch 100 and the pouch cell 10 according to Embodiment 1 of the present invention will be omitted, and the differences will be mainly explained.

Referring to FIG. 7, the pouch 100' according to Example 2 of the present invention may include a first accommodating part 100a and a second accommodating part 100b.

A cup portion 110a, a lid receiving portion 120a, and a film receiving portion 130a may be formed in the first receiving portion 100a of the pouch 100', and the second receiving portion 100b of the pouch 100' may be formed. ), only the lead receiving portion 120b and the film receiving portion 130b excluding the cup portion 110a may be formed. Additionally, the second accommodating part 100b may be disposed on one side of the first accommodating part 100a so as to cover the cup part 110 of the first accommodating part 100a. Specifically, the boundary line between the first accommodating part 100a and the second accommodating part 100b may be folded and the first accommodating part 100a and the second accommodating part 100b may be arranged to face each other.

At this time, assuming that the electrode assembly (E) of the same thickness as that of Example 1 is disposed inside the pouch (100'), the pouch (100') according to Example 2 of the present invention has a cup portion (110a) on only one side. Therefore, the cup portion 110a can be formed to a greater depth than the cup portion 110 of Example 1.

On the other hand, when the boundary line between the first accommodating part 100a and the second accommodating part 100b is folded and the first accommodating part 100a and the second accommodating part 100b are arranged to face each other, the second accommodating part ( The lead accommodating part 120b and the film accommodating part 130b formed in 100b) may be disposed at a position corresponding to the position of the lead accommodating part 120a and the film accommodating part 130a formed in the first accommodating part 100a. there is.

Referring to FIG. 8, the pouch cell 10' according to Example 2 of the present invention has one side convex by the cup portion 110a of the first receiving portion 100a with respect to the electrode assembly E accommodated therein. It may have a shape formed in a similar way. Additionally, a portion of the electrode lead L may protrude from both ends of the convex portion by the cup portion 110a, and a portion of the lead film F disposed on both sides of the electrode lead L may protrude.

Meanwhile, a pair of the electrode leads L and the lead film F of the pouch cell 10' according to the second embodiment of the present invention have a shape that protrudes in both directions. This is only an example, and the electrode lead (L) and the lead film (F) may both protrude in one direction.

Referring to FIG. 9, the pouch cell 10' has an electrode assembly (E) disposed in the cup portion (110a) of the first receiving portion (100a), and an electrode lead (L) connected to the electrode assembly (E) is connected to the pouch ( 100'). Additionally, the portion where the lead film F is disposed may be sealed by bonding the pouch 100 and the lead film F to each other when the edge of the pouch 100' is sealed.

Meanwhile, in addition to the differences described above, the lead receiving portions 120a and 120b and the film receiving portions 130a and 130b according to Example 2 of the present invention are formed to satisfy the following equations (1), (2) and (3). This may be the same as Example 1.

Tl/2 + (Tf + Tp) x 0.58 ≤ Ta ≤ Tl/2 + (Tf + Tp) x 0.68 ...(1)

(Tf + Tp) x 0.58 ≤ Tb ≤ (Tf + Tp) x 0.68 ...(2)

Wl + 2 x (Tf + Tp) x 0.58 ≤ Wa ≤ Wl + 2 x (Tf + Tp) x 0.68 ...(3)

Example 3

The present invention provides a method for manufacturing a pouch cell as Example 3.

The pouch cell manufactured by the manufacturing method according to Example 3 of the present invention may be the same as the pouch cell described in Example 1 or 2. Hereinafter, for convenience of explanation, the manufacturing process of the pouch cell 10 according to Example 1 will be described. Additionally, detailed descriptions of the same configurations as those described in Embodiments 1 and 2 of the present invention will be omitted.

The manufacturing method of the pouch cell 10 according to Example 3 of the present invention may include four steps. Specifically, (a) forming the cup portion 110 in a recessed shape to accommodate the electrode assembly (E) in the pouch film including the inner layer 101 having thermal adhesiveness, (b) the cup portion 110 Forming a lead receiving portion 120 in an indented shape to accommodate a portion of the electrode lead (L) connected to the electrode assembly (E) at one end of the electrode assembly (E), (c) forming an electrode lead (120) on both sides of the lead receiving portion (120). It may include forming the film receiving portion 130 in an indented shape to accommodate a portion of the lead film (F) surrounding the L) and (d) sealing the edge of the molded pouch film.

In step (a), the cup portion 110 may be formed approximately at the center of the pouch film. At this time, the pouch film is pressed with a punch approximately in the shape of the electrode assembly (E), and the cup portion 110 may be formed as the pouch film is stretched. At this time, since the cup portion 110 is formed as the pouch film is stretched in step (a), the part of the pouch 100 forming the cup portion 110 may have a thickness less than that of the pouch film.

In step (b), the lead receiving portion 120 may be formed approximately at one or both ends of the position where the cup portion 110 is formed. At this time, the pouch film is pressed with a punch approximately in the shape of the electrode lead (L), and the lead receiving portion 120 may be formed as the pouch film is stretched. At this time, since the lead receiving portion 120 is formed as the pouch film is stretched in step (b), the portion of the pouch 100 forming the lead receiving portion 120 may be less thick than the pouch film. In particular, the portion adjacent to the portion of the pouch 100 forming the cup portion 110 may have a relatively large decrease in thickness.

In step (c), the film receiving portion 130 may be formed approximately on both sides of the position where the lead receiving portion 120 is formed. At this time, the pouch film is pressed with a punch that has approximately the shape of the lead film (F), and the pouch film is stretched to form the film receiving portion 130. At this time, since the film receiving portion 130 is formed as the pouch film is stretched in step (c), a portion of the pouch 100 forming the film receiving portion 130 may have a thickness less than that of the pouch film. In particular, the portion adjacent to the portion of the pouch 100 forming the lead receiving portion 120 may have a relatively large decrease in thickness.

Accordingly, a portion of the pouch 100 forming the cup portion 110, the lead receiving portion 120, and the film receiving portion 130 may have a thickness less than that of the pouch film.

Meanwhile, the steps (a), (b), and (c) described above are carried out simultaneously using a punch having a shape that can simultaneously mold the cup portion 110, the lead receiving portion 120, and the film receiving portion 130. It may be possible. In this way, when steps (a), (b), and (c) are performed simultaneously, the time required for molding is shortened, and the efficiency of the process can be improved.

In step (d) of the method for manufacturing the pouch cell 10 according to Example 3 of the present invention, the thickness of the lead film and the thickness of the inner layer may change. Specifically, in step (d), the lead film F and the inner layer 101 may partially melt due to heat, thereby reducing the thickness.

Therefore, looking at the change in thickness of the pouch film, in steps (a), (b), and (c), the portion of the pouch 100 forming the cup portion 110, the lead receiving portion 120, and the film receiving portion 130 The thickness of the corresponding portion may be reduced, and the portion corresponding to the portion of the pouch 100 forming the lead receiving portion 120 and the film receiving portion 130 is the thickness of the inner layer 101 in step (d). The thickness may be further reduced due to the reduction.

Meanwhile, in relation to the degree to which the thickness of the lead film (F) and the inner layer 101 is reduced, the sum of the thickness of the lead film and the thickness of the inner layer after the reduction (Tf + Tp)' can satisfy the equation (4) below. there is.

(Tf + Tp) x 0.58 ≤ (Tf + Tp)' ≤ (Tf + Tp) x 0.68 ...(4)

In this regard, as previously described in other Examples 1 and 2, the inner layer 101 of the pouch 100 may include a sealant layer. Preferably, polypropylene (PP) may constitute the sealant layer. Additionally, the lead film (F) may also be made of the same material as the sealant layer.

Meanwhile, in step (d), the pouch 100 may be compressed while applying heat to the edge portion for sealing. Therefore, in step (d), since materials such as polypropylene (PP) can be melted by heat, a portion of the inner layer 101 and the lead film (F) are melted by heat. That is, since the thickness of the inner layer 101 and the lead film (F) decreases as much as they are melted by heat, the sum of the thickness of the lead film and the thickness of the inner layer (Tf + Tp)' after step (d) proceeds. It may be smaller than the sum of the thickness of the lead film and the thickness of the inner layer before progressing (Tf + Tp).

In addition, the extent to which the lead film (F) and the inner layer (101) are partially melted by heat in step (d) and the thickness is reduced is "(Tf + Tp) x 0.58" or more, "( It can be reduced to satisfy Tf + Tp) x 0.68" or less.

Therefore, the pouch cell manufacturing method according to Example 3 of the present invention includes a lead film (F) and an inner layer ( 101) can change the thickness.

Although the present invention has been described above with limited examples and drawings, the present invention is not limited thereto, and the technical idea of the present invention and the following description will be provided by those skilled in the art in the technical field to which the present invention pertains. Various implementations are possible within the scope of equivalence of the claims.

E, E': electrode assembly
L: Electrode lead
F: lead film
10, 10': Pouch cell
101: inner layer
102: metal layer
103: insulating layer
104: outer layer
100, 100': Pouch
100a: first receiving portion
100b: second receiving portion
110, 110a: cup part
120, 120a, 120b: Lead receiving portion
130, 130a, 130b: film receiving portion

Claims (11)

In a pouch formed from a pouch film including an inner layer having thermal adhesiveness,
A cup portion formed in a recessed shape to accommodate an electrode assembly in the form of a stack of electrodes and a separator;
a lead receiving portion formed in a recessed shape at a position corresponding to one end of the cup portion to accommodate a portion of an electrode lead connected to the electrode assembly; and
A film receiving portion formed in a recessed shape on both sides of the lead receiving portion to accommodate a portion of the lead film surrounding the electrode lead,
A pouch wherein the thickness of the electrode lead (Tl), the thickness of the lead film (Tf), the depth of the lead receiving portion (Ta), and the thickness of the inner layer (Tp) satisfy the following equation (1).
Tl/2 + (Tf + Tp) x 0.58 ≤ Ta ≤ Tl/2 + (Tf + Tp) x 0.68 ...(1) In claim 1,
A pouch wherein the thickness of the lead film (Tf), the depth of the film receiving portion (Tb), and the thickness of the inner layer (Tp) satisfy the following equation (2).
(Tf + Tp) x 0.58 ≤ Tb ≤ (Tf + Tp) x 0.68 ...(2) In claim 1,
A pouch wherein the width (Wl) of the electrode lead, the thickness (Tf) of the lead film, the width (Wa) of the lead receiving portion, and the thickness (Tp) of the inner layer satisfy the following equation (3).
Wl + 2 x (Tf + Tp) x 0.58 ≤ Wa ≤ Wl + 2 x (Tf + Tp) x 0.68 ...(3) In claim 1,
A pouch wherein the depth (Ta) of the lead receiving portion has a value greater than the depth (Tb) of the film receiving portion. In claim 1,
A pouch wherein the width (Wl) of the lead receiving portion has a value smaller than the width (Wb) of the film receiving portion. In claim 1,
a first accommodating portion in which the cup portion, the lead accommodating portion, and the film accommodating portion are formed; and
A pouch that may be disposed on one surface of the first accommodating part so as to cover the cup part, and includes a second accommodating part in which the lid accommodating part and the film accommodating part are formed. In claim 6,
A pouch wherein the thickness of the lead film (Tf), the depth of the film receiving portion (Tb), and the thickness of the inner layer (Tp) satisfy the following equation (2).
(Tf + Tp) x 0.58 ≤ Tb ≤ (Tf + Tp) x 0.68 ...(2) In claim 6,
A pouch wherein the width (Wl) of the electrode lead, the thickness (Tf) of the lead film, the width (Wa) of the lead receiving portion, and the thickness (Tp) of the inner layer satisfy the following equation (3).
Wl + 2 x (Tf + Tp) x 0.58 ≤ Wa ≤ Wl + 2 x (Tf + Tp) x 0.68 ...(3) (a) forming a cup portion with an indented shape to accommodate the electrode assembly in a pouch film including an inner layer having thermal adhesiveness;
(b) forming a recessed lead receiving portion at one end of the cup portion to accommodate a portion of an electrode lead connected to the electrode assembly;
(c) forming a film receiving portion with an indented shape to accommodate a portion of the lead film surrounding the electrode lead on both sides of the lead receiving portion; and
(d) comprising sealing the edge of the molded pouch film,
In step (d) above,
The thickness of the lead film and the thickness of the inner layer change,
The sum of the thickness of the lead film and the thickness of the inner layer after change (Tf + Tp)' satisfies the following equation (4).
(Tf + Tp) x 0.58 ≤ (Tf + Tp)' ≤ (Tf + Tp) x 0.68 ...(4) In claim 9,
In step (d) above,
A pouch cell manufacturing method in which the lead film and the inner layer are partially melted by heat and their thickness is reduced. In claim 9,
Steps (a), (b), and (c) are performed simultaneously.

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