Pouch cell with electrode tab and electrode lead connection covered with insulation 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 dated April 15, 2022, and all contents disclosed in the documents of said 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 have high applicability across a range of products and 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 not only have the primary advantage of dramatically reducing the use of fossil fuels, but also have the advantage of not producing any by-products from energy use, so they are attracting attention as a new energy source that is environmentally friendly and improves energy efficiency.

[0005] Currently, the types of secondary batteries that are widely used 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 about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a battery pack may be configured by connecting a plurality of battery cells in series. Also, a battery pack may be configured by connecting a plurality of battery cells in parallel depending on the charge / discharge capacity required for 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 having a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode, and is classified into a jelly roll type in which a long sheet-like positive electrode and a negative electrode coated with an active material are wound up with a separator interposed between them, and a stack type in which a plurality of positive electrodes and negative electrodes of a predetermined size are stacked in sequence with a separator 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 making larger cases and processing them into thinner materials.

[0008] 1 shows a plan view of a typical pouch cell, in which negative and positive electrode leads 12 protrude outside 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 part to be sealed. Fig. 2 is a plan view of the part to be sealed, and Fig. 3 is a cross-sectional view of the part to be sealed. 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 pressurized and heated by a sealing tool to be sealed on the lead film 13 surrounding a part of the electrode lead 12, so that the part of the electrode lead 12, the electrode tab 14, and the electrode assembly 11 are accommodated in the pouch.

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

[0011] 2 to 4, when the metal part 41 and the pouch internal insulating layer 30a come into contact with each other, adhesion between the metal part 41 and the pouch internal insulating layer 30a may occur due to heat applied from the pouch 10 and the lead film 13 during the sealing process and conducted to the metal part 41 via the electrode lead 12. If the electrode assembly 11 and the metal part 41 move after adhesion occurs, a discontinuity occurs in the pouch internal insulating layer 30a, resulting in a problem of 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 the welding portion is covered with a welding tape 15 to prevent the sharp bead of the welding from damaging the inner surface of the pouch. However, the welding tape 15 does not have a heat insulating property, and it is not possible to prevent the phenomenon that the heat conducted through the metal part 41 melts the inner insulating layer 30a and causes adhesion. Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been devised against the background of the conventional technology as described above, and aims to provide an improved pouch cell that can prevent heat conduction by providing an insulating material instead of a 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 insulating material instead of the conventional welding tape.

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

[0016] It is still another technical object of the present invention to provide a pouch cell having an improved structure, a battery pack including the pouch cell, 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 objects and advantages of the present invention not mentioned can be understood from the following description and can be more clearly understood from the embodiments of the present invention. In addition, it is easy to understand that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0018] In order 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 provided.

[0019] In order to solve the above-mentioned problems, the present invention specifies 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 having an insulating layer accommodates a portion of the electrode lead, the electrode tab, and the electrode assembly and is sealed.

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

[0022] The heat insulating material directly or indirectly covers not only the metal portion but also 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 the welding tape 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 the welding tape, or in some cases, the insulating material can be used in addition to the welding tape.

[0024] The heat insulating material may include any of the following materials: expanded synthetic resin, glass fiber, rock wool, mica, perlite, vermiculite, and cellulose. However, the heat insulating material is not limited to these materials, and may be any material that can exhibit heat insulating properties.

[0025] The insulating material may be an insulating film.

[0026] The insulating material may be an 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 thereto and may be manufactured by any method and with any structure as long as it can exhibit heat insulating performance.

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

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

[0032] The heat insulating material may be spaced from the lead film by 2 mm or more 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 may 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 may cover the connection between the electrode tab and the electrode lead to prevent any roughness at the connection from damaging the inner surface of the pouch.

[0035] In one embodiment of the present invention, the metal part is provided by connecting an electrode tab and an electrode lead by welding, and the insulating material has a width wider than the metal part, and the insulating material is attached to both sides of the metal part in an area covering the metal part, and is attached to each other in a portion larger than the width of the metal part, but includes a weld, and may be an insulating film covering 50% or more of the partial 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 will not be described in detail herein. Effect of the Invention

[0039] The present invention covers all or part of the metal part with a heat insulating material, thereby minimizing the phenomenon in which heat conducted to the metal part via the electrode lead during high temperature and high pressure sealing is transferred to the inner surface of the pouch. 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 viewpoint, the present invention provides economy in the production process by eliminating the need for welding tape that was previously attached to prevent damage to the inner surface of the pouch due to the weld bead, and instead has the insulating material covering the metal part perform the same function as the conventional welding tape in order to block the transfer of heat from the metal part to the inner surface of the pouch.

[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 utilize the same equipment as in the case of applying existing welding tape.

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

[0043] In addition to the above, the present invention can achieve various other effects, which will be described in each embodiment, or descriptions of effects that can be easily inferred by a person of ordinary skill in the art will be omitted. [Brief description of the drawings]

[0044] [Figure 1] FIG. 1 is a plan view of a typical pouch cell without insulation. [Diagram 2] FIG. [Diagram 3] FIG. 4 is a cross-sectional view of the part 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 thermal insulating material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] The above-mentioned objects, features and advantages will be described in detail below with reference to the accompanying drawings, so that a person having ordinary skill in the art to which the present invention pertains can easily implement the technical idea of ​​the present invention. In describing the present invention, if a detailed description of a known technology according to the present invention is deemed to obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to 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 the terms "first", "second", etc. 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 it is understood that a first component may also be a second component unless otherwise specified.

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

[0048] Hereinafter, when an arbitrary structure is arranged on the "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 on (or below) the component.

[0049] In addition, 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 there may be other components "intervening" between each component, or each component may be "coupled," "coupled," or "connected" via other components.

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

[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) in this specification. The direction perpendicular to the length direction and parallel to the entire pouch cell in the laid-down state is referred to as the width direction (X). And the direction perpendicular to the entire pouch cell in the laid-down state is referred to as the height direction (Z).

[0053] Hereinafter, preferred embodiments of the present invention will 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 between them. 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 protruding outward from the laminated structure of the electrode plate and the 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 such that a portion of the electrode tab 14 and the electrode lead 12 overlap in the length direction, and the overlapped portions may be connected by welding.

[0059] There is a risk that a weld bead will be generated at the welded portion and damage the inner surface of the pouch, which will be described later. In this regard, if necessary, a welding tape 15 may be attached to both sides of the welded portion. According to the present invention, since a heat insulating material 20, which will be described later, has a structure that covers the metal part 41, the heat 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 a sealed portion of a pouch cell in which a thermal insulating material 20 covers a part of a metal part 41. FIG.

[0061] 2 and 3, the pouch 10 may be manufactured 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 inner space of the pouch from the outer 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 then pressurizing and heating the edges of the sheet facing each other to seal and attach the sheet so as to accommodate the electrode assembly 11 therein. The electrode leads 12 extend from the outside of the pouch 10 through the sealed attachment portions at the edges of the pouch 10.

[0065] The lead film 13 is provided in a region where the electrode lead 12 passes through a sealing 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 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 adhesion between a metal part 41 and an inner insulating layer 30a in a pouch cell not provided with a thermal insulating material.

[0068] 4, in the process of sealing the pouch 10, the heat transferred to the metal part 41 through the electrode lead 12 is transferred to the inner surface of the pouch 10 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, the insulating layer 30 that has adhered to the metal portion 41 may be broken if there is any subsequent flow of the metal portion 41 or the like, which may result in a deterioration of the insulating performance of the pouch cell.

[0070] In this regard, the present invention provides a pouch cell in which at least a part of the partial surface area between the electrode assembly 11 and the lead film 13 of the metal part 41 including the electrode tab 14 and the electrode lead 12 is covered with the heat insulating material 20. 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 insulating material 20 may be applied to the metal portion 41 before the electrode assembly 11 is placed in the pouch 10 .

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

[0073] The above-mentioned covering includes not only cases where the insulation material 20 is in contact with the metal part 41, such as by being directly attached to the metal part 41, but also cases where the heat of the metal part 41 can be blocked from the internal insulating layer 30a of the pouch 10, such as by surrounding the metal part 41 with an air layer or by indirectly covering the metal part 41 by covering a welding tape 15 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 existing 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, when 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 surrounding the metal part 41 with the longitudinal direction (Y direction) of the metal part 41 as an 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 for sufficient heat insulating effect.

[0078] 2 and 3, if the heat insulating material 20 is positioned too close to the adjacent electrode assembly 11, interference with the electrode assembly 11 may occur. Therefore, in order to avoid interference with the electrode assembly 11, the heat insulating material 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 insulating material 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 reduced any more, and the heat insulating performance is reduced.

[0079] 2 and 3, if the insulating material 20 is positioned too close to the lead film 13, interference with the lead film 13 may occur. Since the lead film 13 serves to seal the pouch 10 by welding with heat and pressure, if the insulating material 20 is positioned too close, sealing performance may also be degraded. Therefore, the 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 may cover the connection between the electrode tab 14 and the electrode lead 12 to prevent any unevenness that may be present at the connection between the electrode tab 14 and the electrode lead 12 from damaging the inner surface of the pouch 10. In particular, when the electrode tab 14 and the electrode lead 12 are connected by welding, the insulating material 20 may 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 include any of the following materials: foamed synthetic resin, glass fiber, rock wool, mica, perlite, vermiculite, and cellulose. However, the heat insulating material 20 is not limited to these materials, 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. Any modifications and variations that can be achieved within the meaning and scope of the following claims, as well as equivalent concepts, should be interpreted as being included in the scope of the present invention.

[0084] As described above, the present invention has been described with reference to the illustrative drawings, but 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. 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 Lead 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 Parts X Width direction Y Length direction Z height direction

Claims

1. A stacked electrode assembly; a metal part including an electrode tab connected to the electrode assembly and an electrode lead connected thereto; a lead film attached to both sides of the electrode lead; a heat insulating material that directly or indirectly covers at least a portion of a partial surface of the metal portion between the lead film and the electrode assembly; and a pouch containing a portion of the metal part, the electrode assembly, and the insulating material; Pouch cell.

2. The heat insulating material is a heat insulating film. The pouch cell according to claim 1 .

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

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

5. The heat insulating film has a shape surrounding the metal part with the longitudinal direction as an axis. The pouch cell according to claim 2.

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

7. The heat insulating film is a heat reflective film coated with a thin metal film by a sputtering method. The pouch cell according to claim 2.

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

9. 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 7.

10. The heat insulating material is spaced from the electrode assembly by 2 mm or more. The pouch cell according to any one of claims 1 to 7.

11. the insulating material covers a connection portion between the electrode tab and the electrode lead; The pouch cell according to any one of claims 1 to 7.

Images