Pouch cell with electrode tab and electrode lead connection covered with heat insulating material

Abstract

The present invention discloses a pouch battery cell including an electrode assembly, an electrode tab, an electrode lead, and a pouch. The pouch cell includes an electrode tab connected to the electrode assembly and an electrode lead connected to the electrode tab, and the pouch is welded and sealed onto a lead film surrounding the electrode lead to accommodate a part of a metal part and the electrode assembly. The pouch cell includes a heat insulating material that covers at least a part of a surface of a part of the metal part between the electrode assembly and the lead film. Preferably, the heat insulating material is appropriately spaced from the electrode assembly or the lead film, includes a connection part between the electrode tab and the electrode lead, and covers as large a part of the surface area of ​​the metal part as possible.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0046974, filed April 15, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a pouch battery cell that includes an electrode assembly, an electrode tab, an electrode lead, and a pouch. [Background technology]

[0003] Secondary batteries, which are highly applicable to a wide range of products and have electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) that are driven by electrical sources.

[0004] These secondary batteries have not only the primary advantage of dramatically reducing the use of fossil fuels, but also the advantage of not producing any by-products from the use of energy, and are therefore attracting attention as a new energy source that is environmentally friendly and improves energy efficiency.

[0005] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells, i.e., unit battery cells, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, a battery pack may be configured by connecting multiple battery cells in series. Alternatively, a battery pack may be configured by connecting multiple battery cells in parallel depending on the required charge / discharge capacity of the battery pack. Therefore, the number and electrical connection form of the battery cells included in the battery pack can be variously set depending on the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, secondary batteries are generally classified into cylindrical batteries and prismatic batteries, in which an electrode assembly is housed in a cylindrical or prismatic metal can, and pouch-type batteries, in which an electrode assembly is housed in a pouch-type case made of an aluminum laminate sheet, depending on the shape of the battery case. The electrode assembly housed in the battery case is a chargeable and dischargeable power generating element that includes a positive electrode, a negative electrode, and a separator membrane interposed between the positive and negative electrodes. The secondary batteries are classified into a jelly roll type in which a long sheet-like positive electrode and negative electrode coated with an active material are wound up with a separator membrane interposed between them, and a stack type in which multiple positive electrodes and negative electrodes of a predetermined size are stacked one on top of the other with a separator membrane interposed between them.

[0007] Of these, stack-type and pouch-type batteries are gradually increasing in use due to the increasing capacity of batteries, which has attracted great interest in increasing the area of ​​the case and processing it into thinner materials.

[0008] 1 shows a plan view of a typical pouch cell, in which negative and positive electrode leads 12 protrude from the outside of a pouch 10, and the pouch 10 is sealed onto a lead film 13 that surrounds a portion of the electrode leads 12.

[0009] 2 and 3 show the sealed portion. Fig. 2 is a plan view of the sealed portion, and Fig. 3 is a cross-sectional view of the sealed portion. Referring to these figures, the electrode tab 14 connected to the electrode assembly 11 is connected to the electrode lead 12, and the pouch 10 is sealed by applying pressure and heat using a sealing tool onto the lead film 13 surrounding a portion of the electrode lead 12, so that the portion of the electrode lead 12, the electrode tab 14, and the electrode assembly 11 are housed in the pouch.

[0010] FIG. 4 is a cross-sectional view showing how a metal part 41 consisting of the electrode tab 14 and the electrode lead 12 adheres to an inner insulating layer 30a provided in the pouch in the pouch cell.

[0011] 2 to 4, when the metal part 41 and the pouch's internal insulating layer 30a come into contact with each other, adhesion between the metal part 41 and the pouch's internal insulating layer 30a can occur during the sealing process due to heat generated by the pouch 10 and the lead film 13 and conducted to the metal part 41 via the electrode lead 12. If such adhesion occurs and there is movement of the electrode assembly 11 and the metal part 41, a discontinuity can occur in the pouch's internal insulating layer 30a, resulting in poor insulation performance of the pouch cell.

[0012] Meanwhile, in conventional pouch cells, the electrode tab 14 and the electrode lead 12 are connected by welding, and welding tape 15 is attached to the welded portion to prevent sharp weld beads from damaging the inner surface of the pouch. However, this welding tape 15 does not have heat insulating properties, and it is not possible to prevent adhesion caused by heat conducted through the metal part 41 melting the inner insulating layer 30a. Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention was conceived in light of the background of the prior art as described above, and aims to provide an improved pouch cell that can prevent heat conduction by providing an insulating material instead of welding tape on the inner metal layer of the pouch so that adhesion does not occur between the metal part and the inner insulating layer.

[0014] Another technical object of the present invention is to prevent damage to the inner surface of the pouch caused by the weld bead by using the heat insulating material instead of conventional welding tape.

[0015] Yet another technical object of the present invention is to maximize the insulating effect by appropriately selecting the shape and area of ​​the insulating material that covers the metal part, without causing interference between the electrode assembly or lead film and the insulating material.

[0016] A further technical object of the present invention is to provide a pouch cell with an improved structure, a battery pack including the same, and an electronic device including the battery pack.

[0017] The technical object of the present invention is not limited to the above-mentioned objects, and other unmentioned objects and advantages of the present invention can be understood from the following description and can be more clearly understood from the embodiments of the present invention. Also, it is clear that the objects and advantages of the present invention can be achieved by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0018] To solve the above problems, the present invention provides a pouch cell structure in which a portion of a surface of a metal part connected to an electrode assembly housed in a pouch that can come into contact with an internal insulating layer of the pouch is covered with an insulating material, and the shape of the insulating material is also provided.

[0019] In order to solve the above problem, the present invention also defines the range in which the heat insulating material covers the metal part.

[0020] The means for solving this problem can be applied to a pouch-type battery cell in which an electrode lead is connected to an electrode tab connected to an electrode assembly, and a pouch with an insulating layer accommodates and seals a portion of the electrode lead, the electrode tab, and the electrode assembly.

[0021] The electrode tab and the electrode lead may be connected to each other to form a metal part.

[0022] The heat insulating material covers not only the metal portion but also directly or indirectly at least a portion between the electrode assembly and the lead film.

[0023] The insulating material can cover not only the metal part but also welding tape or the like attached to the metal part. That is, the present invention does not exclude the use of welding tape. The insulating material can also function as welding tape, or in some cases, welding tape can be used and the insulating material can be used in addition.

[0024] The heat insulating material may include any of foamed synthetic resin, glass fiber, rock wool, mica, perlite, vermiculite, and cellulose, but is not limited thereto and may be any material that can exhibit heat insulating properties.

[0025] The heat insulating material may be a heat insulating film.

[0026] The heat insulating material may be a heat insulating film attached to both sides of the metal part.

[0027] The insulating material may be an insulating film having a width greater than that of the metal part and attached to the metal part or to each other (in this case, the width of the insulating material and the metal part means the length in a direction parallel to the entire pouch cell and perpendicular to the length direction, when the direction from the electrode assembly through the electrode tab to the electrode lead is defined as the length direction).

[0028] The heat insulating material may be a heat insulating film having a shape surrounding the metal portion with the longitudinal direction of the metal portion as an axis.

[0029] The heat insulating film may be a heat reflective film coated with a thin metal film by a sputtering method, but the heat insulating film is not limited to this and may be manufactured by any method and with any structure as long as it can exhibit heat insulating properties.

[0030] The heat insulating material may cover 50% or more of the surface area between the electrode assembly and the lead film to provide sufficient heat insulating effect.

[0031] The heat insulating material may be spaced 2 mm or more from the electrode assembly to avoid interference with the electrode assembly.

[0032] The heat insulating material may be spaced 2 mm or more from the lead film so that the lead film can be smoothly welded and so that it does not interfere with the lead film.

[0033] When the electrode tab and the electrode lead are connected by welding, the insulating material can cover the welded portion to prevent the inner surface of the pouch from being damaged by a sharp bead of the welded portion.

[0034] The insulating material can cover the connection portion between the electrode tab and the electrode lead to prevent any roughness that may be present at the connection portion from damaging the inner surface of the pouch.

[0035] In one embodiment of the present invention, the metal part may be provided by connecting an electrode tab and an electrode lead by welding, and the insulating material may be a thermal insulation film having a width wider than that of the metal part, attached to both sides of the metal part in an area covering the metal part, and attached to each other in an area wider than the width of the metal part, including a weld, and covering 50% or more of the area of ​​the metal part between the electrode assembly and the lead film.

[0036] Meanwhile, the present invention provides a pouch-type secondary battery, a battery pack including the pouch-type secondary battery, and an electronic device including the battery pack as a power source.

[0037] The electronic device may be selected from, for example, a computer, a mobile phone, a wearable electronic device, a power tool, an electric vehicle (EV), a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric motorcycle, an electric golf cart, or a power storage system.

[0038] The structure and manufacturing method of these electronic devices are well known in the art, and therefore will not be described in detail herein. [Effects of the Invention]

[0039] The present invention covers all or part of the metal part with an insulating material, thereby minimizing the transfer of heat conducted to the metal part via the electrode lead to the inner surface of the pouch during the high-temperature, high-pressure sealing process. This prevents the inner insulating layer of the pouch from melting and adhering to the metal layer or from being destroyed, resulting in a decrease in insulating performance. That is, the present invention provides a pouch cell with improved stability of insulating performance.

[0040] From another perspective, the present invention eliminates the need for welding tape, which is used to prevent damage to the inner surface of the pouch due to the weld bead, and instead uses an insulating material that covers the metal part to block the heat from the metal part from being transmitted to the inner surface of the pouch, thereby achieving economy in the production process.

[0041] From another viewpoint, the present invention has an economical advantage in that by employing a heat insulating film as the heat insulating material, it is possible to use the same equipment as when existing welding tape is applied.

[0042] From yet another perspective, the present invention can eliminate interference between the insulating material and the electrode assembly or lead film by specifying a distance between the insulating material and the electrode assembly or lead film.

[0043] In addition to the above, the present invention can achieve various other effects, which will be explained in each embodiment, or explanations of effects that can be easily inferred by ordinary engineers will be omitted. [Brief explanation of the drawings]

[0044] [Figure 1] FIG. 1 is a plan view of a typical pouch cell without insulation. [Figure 2] FIG. 10 is a plan view of the part to be sealed. [Figure 3] FIG. 10 is a cross-sectional view of the portion to be sealed. [Figure 4] 1 is a cross-sectional view showing adhesion between a metal part and an internal insulating layer in a conventional pouch cell not provided with a heat insulating material. DETAILED DESCRIPTION OF THE INVENTION

[0045] The above-mentioned objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the technical concept of the present invention. In describing the present invention, if a detailed description of known technologies relating to the present invention is deemed to obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings are used to indicate the same or similar components.

[0046] Although terms such as "first" and "second" are used to indicate various components, it is understood that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, the first component may also be the second component.

[0047] Throughout the specification, unless otherwise specified, each element may be singular or plural.

[0048] Hereinafter, when an arbitrary structure is arranged "on top (or bottom)" of a component or "above (or below)" a component, it means that the arbitrary structure is not only arranged in contact with the upper surface (or lower surface) of the component, but also that other structures may be interposed between the component and the arbitrary structure arranged above (or below) the component.

[0049] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the components may be directly coupled or connected to each other, but that other components may be "intervening" between the components, or that each component may be "coupled," "coupled," or "connected" via other components.

[0050] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. Terms such as "comprise" or "include" in this application should not be interpreted as including all of the components or steps described in the specification, but should be interpreted as meaning that some components or steps may not be included, or that additional components or steps may be included.

[0051] In the entire specification, "A and / or B" means A, B or A and B unless otherwise specified, and "C to D" means C or more and D or less unless otherwise specified.

[0052] For ease of explanation, the direction from the electrode assembly through the electrode tab to the electrode lead is referred to as the length direction (Y). The direction perpendicular to the length direction and parallel to the entire pouch cell in a laid-down state is referred to as the width direction (X). The direction perpendicular to the entire pouch cell in a laid-down state is referred to as the height direction (Z).

[0053] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0054] FIG. 1 is a plan view of a typical pouch cell without any insulation.

[0055] Referring to FIG. 1, a typical pouch cell includes an electrode assembly 11, an electrode tab 14 connected to the electrode assembly 11, an electrode lead 12 connected to the electrode tab 14, a lead film 13 surrounding the electrode lead, and a pouch 10 welded and sealed onto the lead film 13.

[0056] The electrode assembly 11 has a structure in which electrode plates (positive and negative electrode plates) coated with an active material on one or both sides are stacked with a separator interposed therebetween. The electrode tabs 14 may include a positive electrode tab connected to the positive electrode plate and a negative electrode tab connected to the negative electrode plate.

[0057] The electrode tab 14 may be formed by a portion of the electrode plate that is not coated with an active material and that protrudes outward from the laminated structure of the electrode plate and separator. The protruding portions of the stacked electrode plates may overlap each other to form the electrode tab 14.

[0058] The electrode tab 14 and the electrode lead 12 may both be made of an electrically conductive metal material. Accordingly, the electrode tab 14 and the electrode lead 12 may be stacked and overlapped at their opposing ends in the height direction so that a portion of the electrode tab 14 and the electrode lead 12 overlaps in the length direction, and the overlapping portions may be welded to each other.

[0059] A weld bead may be generated at the welded portion, which may damage the inner surface of the pouch, as described below. In this regard, welding tape 15 may be attached to both sides of the welded portion, as necessary. According to the present invention, since the insulating material 20, as described below, has a structure that covers the metal portion 41, the insulating material 20 can also perform the function of the welding tape 15. As a result, the welding tape 15 can be omitted.

[0060] 2 and 3 are a plan view and a cross-sectional view, respectively, of the sealed portion of the pouch cell in which the heat insulating material 20 covers a part of the metal part 41. FIG.

[0061] 2 and 3, the pouch 10 may be fabricated from a sheet including a metal material layer and an insulating layer 30 coated on the front and back surfaces of the metal material layer. The metal material layer functions as a barrier to electromagnetically isolate the electrode assembly 11, and the insulating layer 30 electrically insulates the interior space of the pouch from the exterior space of the pouch.

[0062] The insulating layer 30 may include a PP material.

[0063] The pouch 10 may be made of a flexible material.

[0064] The pouch 10 is formed by folding a sheet and sealing the edges of the sheet facing each other under pressure and heat to accommodate the electrode assembly 11. The electrode leads 12 extend from the outside of the pouch 10 through the sealing attachment portion at the edge of the pouch 10.

[0065] The lead film 13 is provided in the area where the electrode lead 12 passes through the sealed portion of the edge of the pouch 10. A pair of lead films 13 are attached to the upper and lower surfaces of the electrode lead 12, respectively, laminated on both sides of the electrode lead 12, and further extend laterally. The extending direction of the lead film 13 attached to the electrode lead 12 corresponds to the extending direction of the pouch edge.

[0066] With the electrode lead 12 and lead film 13 interposed, when the two edge portions of the pouch are heated and pressurized by a sealing tool, the lead film 13 and the pouch edge portions are welded and sealed.

[0067] FIG. 4 is a cross-sectional view showing the adhesion between the metal part 41 and the inner insulating layer 30a in a pouch cell not provided with a heat insulating material.

[0068] 4, during the sealing process of the pouch 10, heat transferred to the metal part 41 through the electrode lead 12 is transferred to the inner surface of the pouch 10, which is located closer to the inner space of the pouch than the sealing part, which may cause the insulating layer 30 on the inner surface of the pouch 10 to melt and adhere to the metal part 41.

[0069] In this case, if there is a subsequent flow of the metal part 41 or the like, the insulating layer 30 that has adhered to the metal part 41 may be broken, which may result in a deterioration in the insulating performance of the pouch cell.

[0070] In this regard, the present invention provides a pouch cell in which the heat insulating material 20 covers at least a portion of the surface area of ​​the metal part 41, which includes the electrode tab 14 and the electrode lead 12, between the electrode assembly 11 and the lead film 13. This reduces the risk of melting the inner insulating layer 30a due to heat transfer from the metal part 41 to the inner insulating layer 30a during sealing, thereby preventing a decrease in insulating performance.

[0071] The heat insulating material 20 may be applied to the metal part 41 before the electrode assembly 11 is placed in the pouch 10 .

[0072] The shape and range of the heat insulating material 20 covering the metal part 41 will be described below.

[0073] The term "covering" as used above not only refers to cases where the insulating material 20 is in contact with the metal part 41, such as when it is directly attached to the metal part 41, but also includes cases where the heat of the metal part 41 can be blocked from the internal insulating layer 30a of the pouch 10, such as when the insulating material 20 is surrounded by an air layer between the metal part 41 and the metal part 41, or when the insulating material 20 is indirectly covered by covering the metal part 41 with welding tape 15 or the like that is directly attached to the metal part 41, as shown in Figure 1.

[0074] The heat insulating material 20 may be a heat insulating film. The effect of the present invention can be fully realized by using a tape-shaped heat insulating film 20 and simply replacing the welding tape 15 with the heat insulating film 20 in the process of attaching the existing welding tape 15, as shown in FIG.

[0075] When the heat insulating film 20 covers the metal part 41, the heat insulating film 20 may be attached to both sides of the metal part 41. In this case, if the width (length in the X direction) of the heat insulating film 20 is wider than the width of the metal part 41, it is possible to cover both sides of the metal part 41.

[0076] The heat insulating film 20 can also cover the metal part 41 in a shape that surrounds the metal part 41 with the longitudinal direction (Y direction) of the metal part 41 as the axis. In this case, the heat insulating film 20 can surround the metal part 41 one or more times, and can also surround it two or more times to enhance the heat insulating function of the heat insulating film 20.

[0077] The heat insulating material 20 can cover 50% or more of the partial surface area between the electrode assembly 11 and the lead film 13 to provide sufficient heat insulating effect.

[0078] 2 and 3, if the heat insulator 20 is positioned too close to an adjacent electrode assembly 11, interference with the electrode assembly 11 may occur. Therefore, to avoid interference with the electrode assembly 11, the heat insulator 20 can be positioned at a predetermined distance from the electrode assembly 11. The distance may be 2 mm or more. If the distance is less than 2 mm, the heat insulator 20 is more likely to interfere with the electrode assembly 11 during handling of the battery cell. The distance may be 5 mm or less. If the distance is more than 5 mm, the possibility of interference with the electrode assembly 11 is not further reduced, and the heat insulating performance is reduced.

[0079] 2 and 3, if the heat insulating material 20 is positioned too close to the lead film 13, interference with the lead film 13 may occur. Because the lead film 13 seals the pouch 10 by welding with heat and pressure, if the heat insulating material 20 is positioned too close, sealing performance may also be reduced. Therefore, the heat insulating material 20 can be positioned at a predetermined distance from the lead film 13. The distance may be 2 mm or more. If the distance is less than 2 mm, there is a high possibility that sealing may be affected.

[0080] The insulating material 20 can cover the connection portion between the electrode tab 14 and the electrode lead 12 to prevent any unevenness that may be present at the connection portion from damaging the inner surface of the pouch 10. In particular, if the electrode tab 14 and the electrode lead 12 are connected by welding, the insulating material 20 can be positioned to cover the welded portion to prevent the inner surface of the pouch 10 from being damaged by a sharp bead of the welded portion.

[0081] The heat insulating material 20 may contain any of foamed synthetic resin, glass fiber, rock wool, mica, perlite, vermiculite, and cellulose, but is not limited thereto and may be any material that can exhibit heat insulating properties.

[0082] When the heat insulating material 20 is the heat insulating film 20, the heat insulating film 20 may be a heat reflective film coated with a thin metal film by a sputtering method. However, the heat insulating film 20 is not limited to this, and may be manufactured by any method and with any structure as long as it can exhibit heat insulating performance.

[0083] It should be understood that the above-described embodiments are illustrative in all respects and are not limiting, and the scope of the present invention is defined by the following claims rather than the above detailed description. All modifications and variations within the meaning and scope of the following claims, as well as equivalent concepts, should be construed as being included within the scope of the present invention.

[0084] Although the present invention has been described above with reference to illustrative drawings, the present invention is not limited to the embodiments and drawings disclosed in this specification, and it is obvious that various modifications can be made by those skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention are not explicitly described and explained while describing the embodiments of the present invention, it is natural that the effects that can be predicted by the configuration should also be recognized. [Explanation of symbols]

[0085] 10 pouches 11 Electrode assembly 12 electrode leads 13 Lead film 14 Electrode tab 15 Welding tape 20. Insulation material / insulation film 30a inner insulation layer 30b Outer insulating layer 40 Adhesive area 41 Metal part X Width direction Y length direction Z height direction

Claims

1. stacked electrode assembly; a metal part including an electrode tab connected to the stacked electrode assembly and an electrode lead connected thereto; lead films attached to both sides of the electrode leads; a heat insulating material that directly or indirectly covers at least a portion of the surface of the metal portion between the lead film and the stacked electrode assembly; and a pouch that accommodates a portion of the metal part, the stacked electrode assembly, and the thermal insulating material; the heat insulating material is a heat insulating film, The pouch cell, wherein the heat insulating film is a heat reflective film coated with a thin metal film by a sputtering method.

2. The heat insulating film is attached to at least a portion of both surfaces of the metal part. The pouch cell of claim 1 .

3. The width of the heat insulating film is wider than the width of the metal part. The pouch cell according to claim 2 .

4. The heat insulating film has a shape that surrounds the metal part with the longitudinal direction as an axis. The pouch cell of claim 1 .

5. The heat insulating film surrounds the metal part one or more times. The pouch cell according to claim 4.

6. The insulating material includes any one of foamed synthetic resin, glass fiber, rock wool, mica, perlite, vermiculite, and cellulose. The pouch cell of claim 1 .

7. the heat insulating material covers 50% or more of the surface area of ​​the metal portion between the lead film and the stacked electrode assembly; The pouch cell according to any one of claims 1 to 6.

8. The heat insulating material is spaced from the lead film by 2 mm or more. The pouch cell according to any one of claims 1 to 6.

9. The heat insulating material is spaced from the stacked electrode assembly by 2 mm or more. The pouch cell according to any one of claims 1 to 6.

10. The heat insulating material is spaced apart from the stacked electrode assembly by 5 mm or less. The pouch cell according to any one of claims 1 to 6.

11. the heat insulating material covers the connection portion between the electrode tab and the electrode lead. The pouch cell according to any one of claims 1 to 6.

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