Pouch-type secondary battery with excellent insulation and heat dissipation properties

Abstract

The present invention provides a pouch-type secondary battery including a pouch-type battery case including an electrode assembly storage portion and a sealing portion, an electrode assembly stored in the storage portion, and an insulating coating layer laminated on the sealing portion, the insulating coating layer including a portion containing a binder and heat dissipation particles having a thermal conductivity of 0.2 W / (mk) or more, and a joint portion containing the binder but not the heat dissipation particles.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0115869 filed on August 31, 2021, and Korean Patent Application No. 10-2022-0088456 filed on July 18, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a pouch-type secondary battery having excellent insulation and heat dissipation properties. [Background technology]

[0003] Recently, the use of secondary batteries has been increasing. In terms of battery shape, there is a tendency for the demand to be increased for rectangular secondary batteries and pouch-type secondary batteries, which are thin and applicable to products such as mobile phones, while in terms of materials, there is an increasing demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries, which have advantages such as high energy density, discharge voltage, and output stability.

[0004] Secondary batteries are also classified according to the structure of the electrode assembly, which has a positive electrode / separator / negative electrode structure. Examples of such electrode assemblies include a jelly roll (wound type) electrode assembly in which long sheet-type positive and negative electrodes are wound with a separator interposed, a stack type electrode assembly in which a number of positive and negative electrodes cut into a predetermined size are stacked in order with a separator interposed, and a stack / folding type electrode assembly in which a bi-cell in which a predetermined unit of positive and negative electrodes are stacked with a separator interposed or a full cell is wrapped in a separator film.

[0005] Recently, pouch-type batteries, which have a structure in which a stack-type or stack / folding-type electrode assembly is built into a pouch-type battery case made of an aluminum laminate sheet, have been attracting much attention due to their low manufacturing cost, small weight, easy shape modification, etc., and their usage is gradually increasing.

[0006] The general structure of a typical conventional pouch-type secondary battery is shown in Fig. 1. Referring to Fig. 1, a pouch-type secondary battery 100 includes an electrode assembly 20, an electrode tab 50 extending from the electrode assembly 20, an electrode lead 40 welded to the electrode tab 50, and a battery case 10 accommodating the electrode assembly 20. Lead insulating coating parts 60 are attached to parts of the upper and lower surfaces of the electrode lead 40 to increase the degree of sealing with the battery case 10 and at the same time ensure electrical insulation.

[0007] Such pouch-type batteries are manufactured by encasing an electrode assembly in a laminate sheet, injecting an electrolyte, and sealing the laminate by heat sealing, etc., but during this manufacturing process, the heat-sealed portion (sealing portion) may become contaminated during the electrolyte injection process, or the resin layer may protrude outward due to excessive melting and / or pressure of the innermost resin layer of the laminate sheet. The contamination of the sealing portion or the protrusion of the inner resin layer outward acts as a cause of incomplete sealing, and defects in the sealing portion can cause serious problems such as moisture penetration and electrolyte leakage.

[0008] It is also known that in pouch-type batteries, a metal layer can become exposed at the edge of the laminate sheet that constitutes the battery case, causing a dielectric breakdown phenomenon.

[0009] In order to solve this problem, the prior art has proposed a method of insulating the outer periphery of the heat-sealed part using a PET label, tape, etc. However, when insulating the outer periphery of the heat-sealed part using a PET label, tape, etc., it is known that the label and tape may peel off or defects such as air bubbles or wrinkles may occur.

[0010] Recently, pouch-type batteries have been introduced that have improved sealing by applying a sealing aid to the outer casing of the heat-sealed part. However, it is not easy to apply a sealing aid with a certain viscosity and fluidity to the outer casing of the heat-sealed part with a thin vertical cross section, and the sealing aid flows down during the hardening process after application, making it difficult to achieve the desired effect, making it difficult to apply to actual mass production.

[0011] Therefore, there is a need for development of a technology that can solve the problems of the conventional technology, improve the sealing performance of the heat-sealed portion, and reliably prevent the dielectric breakdown phenomenon. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Republic of Korea Patent No. 10-1216422 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been devised to solve the above-mentioned problems of the prior art, The object of the present invention is to provide a pouch-type secondary battery having improved sealing properties and insulating characteristics of the sealing part.

[0014] Another object of the present invention is to provide a pouch-type secondary battery having improved heat dissipation characteristics at the sealing portion. [Means for solving the problem]

[0015] In order to achieve the above object, the present invention provides a pouch-type battery case including an electrode assembly receiving portion and a sealing portion; an electrode assembly accommodated in the electrode assembly accommodating portion, the sealing portion includes a bent portion formed by bending the sealing portion toward the electrode assembly receiving portion, a first insulating coating layer is bonded to an inner surface, an outer surface, and an end surface of the bent portion that defines a boundary between the inner surface and the outer surface based on the electrode assembly receiving portion of the bent portion; an outer surface of the first insulating coating layer bonded to the inner surface of the bent portion is bonded to an outer surface of a wall of the electrode assembly receiving portion; The first insulating coating layer includes a portion containing a binder and heat-dissipating particles having a thermal conductivity of 0.2 W / (mk) or more, and a joint portion containing the binder but not the heat-dissipating particles, the joint portion being bonded to an outer surface of a wall of the electrode assembly housing portion, to provide a pouch-type secondary battery.

[0016] In an embodiment of the present invention, the joint portion may have a thickness of 1 μm to 100 μm from an outer surface of the wall of the electrode assembly receiving portion.

[0017] In an embodiment of the present invention, a first insulating coating layer on an inner surface, an outer surface, and an end surface of the bent portion that forms a boundary between the inner surface and the outer surface based on an electrode assembly receiving portion of the bent portion may be formed to be connected to each other.

[0018] In an embodiment of the present invention, the first insulating coating layer on the inner surface, the outer surface, and the end surface of the bent portion that forms a boundary between the inner surface and the outer surface based on the electrode assembly receiving portion of the bent portion may be formed by folding and adhering an insulating coating film.

[0019] In an embodiment of the present invention, the insulating coating film may be bonded by heat fusion.

[0020] In an embodiment of the present invention, the sealing portion further includes a terrace portion located in a direction parallel to an upper surface or a lower surface of the electrode assembly receiving portion, a second insulating coating layer is further laminated in a space formed between the terrace portion and an outer surface of the wall of the electrode assembly receiving portion; The second insulating coating layer includes a portion containing a binder and heat-dissipating particles having a thermal conductivity of 0.2 W / (mk) or more, and a joint portion containing the binder but not the heat-dissipating particles, and the joint portion may be bonded to an outer surface of a wall of the electrode assembly housing.

[0021] In an embodiment of the present invention, the joint portion may have a thickness of 1 μm to 100 μm from an outer surface of the wall of the electrode assembly receiving portion.

[0022] In an embodiment of the present invention, the height of the second insulating coating layer may be equal to or lower than the height of the wall of the electrode assembly receiving portion.

[0023] In an embodiment of the present invention, an electrode lead may be located at an end of the terrace portion.

[0024] In one embodiment of the present invention, the portion of the first and / or second insulating coating layer containing the binder and heat-dissipating particles may include 10 to 90% by weight of the binder and 10 to 90% by weight of the heat-dissipating particles.

[0025] In one embodiment of the present invention, the heat dissipating particles may have an average particle size of 0.1 μm to 10 μm.

[0026] In an embodiment of the present invention, the folding portion may include a portion in which the sealing portion is folded and overlapped in two or more layers. Effect of the Invention

[0027] The pouch-type secondary battery of the present invention provides excellent sealing properties of the sealing portion and excellent insulation properties, and in particular provides excellent heat dissipation properties.

[0028] Therefore, the pouch-type secondary battery of the present invention provides the effect of significantly improving the safety of the battery. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is an exploded perspective view of a conventional pouch-type secondary battery. [Diagram 2] 1 is a perspective view showing a schematic diagram of an embodiment of a pouch-type secondary battery of the present invention. [Diagram 3] 3 is a cross-sectional view taken along line AA of the pouch-type secondary battery in FIG. 2. [Figure 4] 1 is a cross-sectional view showing a schematic configuration of an insulating coating film according to one embodiment of the present invention. [Diagram 5] 1 is a perspective view showing a schematic diagram of an embodiment of a pouch-type secondary battery of the present invention. [Figure 6] 6 is a cross-sectional view taken along line BB of the pouch-type secondary battery of FIG. 5. [Figure 7] FIG. 1 is a perspective view showing a typical form of an insulating coating bar according to one embodiment of the present invention. [Figure 8] 1 is a cross-sectional view that illustrates a schematic diagram of an embodiment of a pouch-type secondary battery of the present invention. [Figure 9] 1 is a cross-sectional view that illustrates a schematic diagram of an embodiment of a pouch-type secondary battery of the present invention. [Figure 10] 1 is a cross-sectional view that illustrates a schematic diagram of an embodiment of a pouch-type secondary battery of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily practice the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. The same reference numerals are used throughout the specification to refer to similar parts.

[0031] When a component is said to be "connected, provided, or mounted" to another component, it should be understood that it can be directly connected or mounted to the other component, but there can also be another component in between. On the other hand, when a component is said to be "directly connected, provided, or mounted" to another component, it should be understood that there is no other component in between. On the other hand, other expressions describing the relationship between components, such as "on" and "directly on," or "between" and "immediately between," or "adjacent to" and "directly adjacent to," should be interpreted in the same way.

[0032] FIG. 1 is an exploded perspective view of a conventional pouch-type secondary battery which is also applied to the present invention, and FIG. 2 and FIG. 5 are perspective views each showing a schematic embodiment of the pouch-type secondary battery of the present invention.

[0033] As shown in FIGS. 1 and 2, the pouch-type secondary battery 100 of the present invention includes a pouch-type battery case 10 including an electrode assembly receiving portion 11 and a sealing portion 12, and an electrode assembly 20 received in the receiving portion 11. The sealing portion 12 includes a bent portion 12-1 formed by bending the sealing portion toward the electrode assembly receiving portion 11. An insulating coating layer 30 is bonded to the inner surface, the outer surface, and the end surface of the bent portion that forms the boundary between the inner surface and the outer surface of the bent portion 12-1 based on the electrode assembly receiving portion 11. The outer surface of the insulating coating layer 30 bonded to the inner surface of the bent portion 12-1 is bonded to the outer surface of the wall of the electrode assembly receiving portion 11. The insulating coating layer 30 includes a portion containing a binder and heat dissipating particles 32 having a thermal conductivity of 0.2 W / (mk) or more, and a joint portion 30a containing the binder but not the heat dissipating particles 32, and the joint portion 30a is bonded to an outer surface of a wall of the electrode assembly receiving portion.

[0034] Although efforts have been made to improve the sealing property and insulating properties of the sealing part in conventional pouch-type secondary batteries, the improvements have not been sufficient. The present invention has the feature of improving the sealing property and insulating properties of the sealing part while at the same time significantly improving the heat dissipation properties. In particular, the insulating layer formed in the conventional sealing part contains heat dissipation particles overall, which means that it has insufficient adhesive strength to the pouch-type battery case and is unable to maintain an adhesive state for a long period of time. The present invention has a technical feature of solving the problems of the conventional technology as described above.

[0035] The bonding portion 30a may have a thickness of 1 μm to 100 μm, and preferably 5 μm to 20 μm, from the outer surface of the wall of the electrode assembly receiving portion 11. If the thickness of the bonding portion 30a is less than 1 μm, the adhesive strength decreases, and if the thickness exceeds 100 μm, the heat dissipation effect decreases.

[0036] The insulating coating layer 30 on the inner surface, the outer surface, and the end surface of the bent portion forming the boundary between the inner surface and the outer surface based on the electrode assembly receiving portion 11 of the bent portion 12-1 may be connected to each other.

[0037] The insulating coating layer 30 on the inner surface, outer surface, and end surface of the bent portion forming the boundary between the inner surface and the outer surface based on the electrode assembly receiving portion 11 of the bent portion may be formed by folding and adhering the insulating coating film 34 as shown in Fig. 4. In this case, the folded portion of the insulating coating film 34 may be adhered to the end surface of the bent portion forming the boundary between the inner surface and the outer surface.

[0038] The insulating coating film 34 can be bonded by heat fusion.

[0039] In one embodiment of the present invention, the insulating coating film 34 may be manufactured in the form illustrated in Fig. 4. The insulating coating film 34 may be manufactured by, for example, preparing a heat dissipating composition for insulating coating, which includes a binder and heat dissipating particles having a thermal conductivity of 0.2 W / (mk) or more, applying the composition to a substrate and curing the composition to form a first coating layer, and then partitioning an upper surface of the first coating layer, coating a portion of the heat dissipating composition for insulating coating, and coating the remaining portion with a binder composition, and curing the resulting layer. The insulating coating film 34 may be manufactured by a known extrusion (injection) method.

[0040] In addition, after forming the first coating layer, the upper surface of the first coating layer may be partitioned, and the binder composition may be coated and cured only on some of the bonding portions 30a. The insulating coating film 34 may be manufactured by a known extrusion (injection) method.

[0041] In one embodiment of the present invention, the insulating coating film 34 may have a thickness of 20 μm to 1 mm, and preferably 40 μm to 200 μm.

[0042] In one embodiment of the present invention, the sealing portion 12 further includes a terrace portion (non-bent portion) located in a direction parallel to the upper or lower surface of the electrode assembly receiving portion 11, and in this case, as shown in Figures 5 and 6, the insulating coating layer 30' can be further laminated in the space formed between the terrace portion and the outer surface of the wall of the electrode assembly receiving portion 11.

[0043] The insulating coating layer 30' includes a portion containing a binder and heat dissipating particles 32 having a thermal conductivity of 0.2 W / (mk) or more, and a joint portion 30'a containing a binder but not heat dissipating particles 32, and the joint portion 30'a may be in a form adhered to the outer surface of the wall of the electrode assembly housing portion.

[0044] The bonding portion 30'a may have a thickness of 1 μm to 100 μm, and preferably 5 μm to 20 μm, from the outer surface of the wall of the electrode assembly receiving portion 11. If the thickness of the bonding portion 30'a is less than 1 μm, the adhesive strength decreases, and if it exceeds 100 μm, the heat dissipation effect decreases.

[0045] The insulating coating layer 30' may be formed in an appropriate shape in the space formed between the terrace portion and the outer surface of the wall 11 of the electrode assembly receiving portion, for example, as shown in Figures 5 and 6, it may be formed in a shape similar to a rectangular prism, but is not limited thereto.

[0046] The insulating coating layer 30' may be formed using an insulating coating bar 36 as shown in Fig. 7. The insulating coating bar 36 may have a shape similar to a rectangular prism, but may have a suitable shape depending on the shape of the pouch-type battery case.

[0047] The insulating coating bar 36 can be bonded by heat fusion, or can be bonded using a separate adhesive.

[0048] In one embodiment of the present invention, the insulating coating layer 30' may be formed only on the terrace portion in the direction in which the electrode lead 40 is located, as shown in Figures 5 and 6, or may be formed on both the terrace portion in the direction in which the electrode lead 40 is located and the terrace portion on the opposite side, as shown in Figure 10.

[0049] In one embodiment of the present invention, the insulating coating layer 30' may be formed to cover the tip of the terrace portion as shown in FIG. 9, or may be formed to cover the tip of the terrace portion and part or all of the lower surface of the terrace portion.

[0050] In one embodiment of the present invention, the height of the insulating coating layer 30' may be equal to or lower than the height of the wall 11 of the electrode assembly receiving portion.

[0051] In one embodiment of the present invention, an electrode lead 40 may be located at the tip of the terrace portion, as shown in FIGS.

[0052] In one embodiment of the present invention, the portions 30b, 30'b of the insulating coating layers 30, 30' containing the binder and heat dissipating particles may contain 10-90% by weight of the binder and 10-90% by weight of the heat dissipating particles, preferably 30-70% by weight of the binder and 30-70% by weight of the heat dissipating particles, and more preferably 40-60% by weight of the binder and 40-60% by weight of the heat dissipating particles. In addition to the above components, known components used for insulating coatings in this field may be further contained.

[0053] If the heat dissipating particles are contained in an amount less than 10 wt %, it is difficult to expect a heat dissipating effect, and if the amount exceeds 90 wt %, the adhesive strength of the insulating coating layers 30, 30' may decrease, which is undesirable.

[0054] The binder may be a photocurable polymer or a thermosetting polymer. The polymer may be, but is not limited to, polyurethane resin, polyethylene resin, polypropylene resin, polybutylene resin, polystyrene resin, polyethylene terephthalate resin, polycarbonate resin, polybutadiene resin, unsaturated polyester resin, polyimide resin, polyacrylate resin, etc., which may be used alone or in a mixture of two or more kinds. The polyacrylate resin may be polyester acrylate, epoxy acrylate, urethane acrylate, etc.

[0055] Examples of the heat dissipating particles having a thermal conductivity of 0.2 W / (mk) or more include aluminum, carbon, copper, chromium, titanium, and stainless steel particles, and these may be used alone or in combination of two or more.

[0056] The heat dissipating particles may have an average particle size of 0.1 μm to 10 μm, but are not limited to this range.

[0057] The heat dissipating particles preferably have an electrical conductivity of 0.2 S / cm or less. If the electrical conductivity is higher than the range, the insulating properties may be reduced, which is not preferable.

[0058] In one embodiment of the present invention, the bonding portion 30a, 30'a of the insulating coating layer 30, 30' corresponding to the outer surface of the wall of the electrode assembly housing portion that does not contain heat dissipating particles may contain a binder and an additive commonly used in this field to improve adhesion, or may be composed only of the binder exemplified above.

[0059] In an embodiment of the present invention, the sealing portion 12 may include a bent portion 12-1 formed by bending the sealing portion toward the electrode assembly receiving portion, as shown in FIGS.

[0060] The bent portion 12-1 may be bent at an angle of 80 degrees to 180 degrees, preferably 85 degrees to 145 degrees, and more preferably 90 degrees to 100 degrees with respect to the non-bent portion of the sealing portion.

[0061] In one embodiment of the present invention, the bent portion 12-1 may include a portion in which the sealing portion is folded and overlapped two or more times as shown in FIG.

[0062] In an embodiment of the present invention, the electrode assembly 20 may be of any type known in the art without limitation, and therefore a detailed description thereof will be omitted.

[0063] The electrode assembly 20 is not particularly limited as long as it has a structure in which a plurality of electrode tabs are connected to form a positive electrode and a negative electrode as shown in FIG. 1, and preferably has a folding type structure, a stack type structure, a stack / folding type structure, or a lamination-stack type structure.

[0064] The battery case 10 may be a pouch-type case made of a laminate sheet including a metal layer and a resin layer, for example, an aluminum laminate sheet, and including an electrode assembly receiving portion and a sealing portion.

[0065] The battery case 10 may be formed of a single unit of laminate sheet. In this case, a case body portion including an electrode assembly receiving portion and a cover portion coupled to the case body to cover the electrode assembly receiving portion may be formed around a folding portion.

[0066] A terrace portion on which an electrode terminal having an electrode tab protruding from an electrode assembly and an electrode lead combined therewith may be located may be located at a portion facing the folded portion of the laminate sheet, and side sealing portions may be located adjacent to both ends of the terrace portion. The side sealing portions may have folded portions.

[0067] Example 1: Production of insulating coating film A polyurethane binder and aluminum / carbon composite (particle size 0.1 μm) as heat dissipating particles with a thermal conductivity of 0.2 W / (mk) or more were added to an acetone solvent in a weight ratio of 1:9 to prepare a heat dissipating composition for insulating coating.

[0068] In addition, a polyurethane binder was added to an acetone solvent to prepare a binder composition for insulating coating.

[0069] The heat dissipating composition for insulating coating was applied to a substrate and cured to form a first coating layer.

[0070] Next, the upper surface of the first coating layer was partitioned according to the shape of the insulating coating film shown in FIG. 4, and the portion to be bonded to the outer surface of the wall of the electrode assembly housing was coated with the insulating coating binder composition, and the remaining portion was coated with the insulating coating heat dissipation composition and cured to prepare the insulating coating film as shown in FIG. 4.

[0071] Comparative Example 1: Production of insulating coating film The heat dissipating composition for insulating coating prepared in Example 1 was applied to the same thickness as the insulating coating film prepared in Example 1 and cured to prepare an insulating coating film.

[0072] Example 2: Formation of an insulating layer on the sealing part of a pouch-type secondary battery A portion of the sealing part of the pouch-type battery case containing the electrode assembly was left on the electrode assembly containing part side, and the remaining part was folded 90 degrees toward the electrode assembly containing part to form a folded part. Then, the insulating coating film prepared in Example 1 was folded and heat-sealed to form an insulating coating layer as shown in FIG.

[0073] Comparative Example 2: Formation of an insulating layer on the sealing portion of a pouch-type secondary battery An insulating coating layer was formed in the same manner as in Example 2, except that the insulating coating film prepared in Comparative Example 1 was used.

[0074] Test Example 1: Evaluation of adhesive performance of insulating coating layer The pouch-type secondary batteries of Example 2 and Comparative Example 2 were stored at 65° C. and checked for the presence or absence of the insulating coating layer. The results are shown in Table 1 below.

[0075] [Table 1]

[0076] Although the present invention has been described with reference to the above preferred embodiment, various modifications and variations can be made without departing from the spirit and scope of the invention, and it is therefore intended by the appended claims to cover such modifications and variations as fall within the spirit and scope of the invention. [Explanation of symbols]

[0077] 10: Battery case 11: Electrode assembly storage section 12: Sealing section 12-1: Bending section 20: Electrode assembly 30, 30': Insulating coating layer 30a, 30'a: Joint of insulating coating layer to the outer surface of the wall of the electrode assembly housing 30b, 30'b: Parts containing binder and heat dissipating particles 32: Heat dissipation particles 34: Insulation coating film 36: Insulation coating bar 40: Electrode lead 50: Electrode tab 60: Lead insulation coating part

Claims

1. a pouch-type battery case including an electrode assembly receiving portion and a sealing portion; an electrode assembly accommodated in the electrode assembly accommodating portion, the sealing portion includes a bent portion formed by bending the sealing portion toward a wall of the electrode assembly receiving portion, a first insulating coating layer is bonded to an inner surface, an outer surface, and an end surface of the bent portion that defines a boundary between the inner surface and the outer surface based on the electrode assembly receiving portion of the bent portion; an outer surface of the first insulating coating layer bonded to the inner surface of the bent portion is bonded to an outer surface of a wall of the electrode assembly receiving portion; the first insulating coating layer includes a portion containing a binder and heat dissipating particles and a joint portion containing the binder and not containing the heat dissipating particles, the joint portion of the first insulating coating layer being joined to an outer surface of a wall of the electrode assembly receiving portion; The heat dissipating particles are selected from the group consisting of aluminum particles, carbon particles, copper particles, chromium particles, titanium particles, and stainless steel particles, which may be one type alone or two or more types in combination.

2. 2. The pouch-type secondary battery of claim 1, wherein the joint portion of the first insulating coating layer has a thickness of 1 μm to 100 μm from an outer surface of the wall of the electrode assembly receiving portion.

3. 2. The pouch-type secondary battery according to claim 1, wherein the first insulating coating layer on an inner surface, an outer surface, and an end surface of the bent portion that defines a boundary between the inner surface and the outer surface based on the electrode assembly receiving portion of the bent portion are connected to each other.

4. 4. The pouch-type secondary battery according to claim 3, wherein the first insulating coating layer on an inner surface, an outer surface, and an end surface of the bent portion that defines a boundary between the inner surface and the outer surface based on the electrode assembly receiving portion of the bent portion is formed by folding and adhering an insulating coating film.

5. 5. The pouch-type secondary battery according to claim 4, wherein the insulating coating film is bonded by thermal fusion.

6. the sealing portion further includes a terrace portion extending in a direction parallel to an upper surface or a lower surface of the electrode assembly receiving portion, a second insulating coating layer is further laminated in a space formed between the terrace portion and an outer surface of the wall of the electrode assembly receiving portion; 2. The pouch-type secondary battery according to claim 1, wherein the second insulating coating layer includes a portion containing a binder and the heat-dissipating particles and a joint portion containing the binder and not the heat-dissipating particles, and the joint portion of the second insulating coating layer is joined to an outer surface of a wall of the electrode assembly housing portion.

7. 7. The pouch-type secondary battery of claim 6, wherein the joint portion of the second insulating coating layer has a thickness of 1 μm to 100 μm from an outer surface of the wall of the electrode assembly receiving portion.

8. 7. The pouch-type secondary battery according to claim 6, wherein a height of the second insulating coating layer is equal to or less than a length between an upper surface and a lower surface of the electrode assembly receiving portion.

9. The pouch-type secondary battery according to claim 8 , wherein an electrode lead is located at a tip of the terrace portion.

10. 7. The pouch-type secondary battery according to claim 1 or 6, wherein the portion containing the binder and the heat-dissipating particles in the first and / or second insulating coating layer contains 10 to 90% by weight of the binder and 10 to 90% by weight of the heat-dissipating particles.

11. The pouch-type secondary battery according to claim 1 , wherein the folding portion comprises a portion where the sealing portion is folded twice or more.

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