Rechargeable batteries and devices containing them

Abstract

The present invention has a problem in that even if only the welded portion is reinforced by taping, the portion of the electrode tab connected to the end of the electrode is not protected, making it difficult to completely solve the problem of disconnection in the relatively weak point between the welded portion and the electrode. A secondary battery according to various embodiments includes an electrode assembly including a plurality of electrodes, an electrode tab extending from at least one of the plurality of electrodes, and a separator membrane interposed between the plurality of electrodes; an electrode lead electrically connected to the electrode tab; and a protective portion covering at least a portion of the plurality of electrodes, at least a portion of the electrode tab, and a portion of the electrode lead, wherein at least a portion of the protective portion may be formed of an insulating material that shrinks with a predetermined energy source. Other embodiments are also possible.

Description

Technical Field

[0001] The present disclosure relates to secondary batteries and devices including the same.

Background Art

[0002] Secondary batteries can be charged and discharged and are widely used in mobile devices such as digital cameras, mobile phones, and notebook computers. In particular, in recent years, they have attracted attention as energy sources for electric vehicles, energy storage systems (ESS), etc. On the other hand, in electric vehicles and energy storage systems, as higher-capacity and higher-output power are required, medium- to large-sized battery devices such as battery modules in which a large number of secondary batteries are housed inside a housing and battery packs including a large number of battery modules are widely used.

[0003] Conventionally, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, etc. have been mainly used as secondary batteries, and in recent years, lithium-ion batteries have been increasingly used. In the case of lithium-ion batteries, copper, aluminum foil, etc. are used as metal current collectors for the positive and negative electrodes, respectively, and a method of manufacturing electrodes by laminating a negative electrode active material or a positive electrode active material on both sides thereof can be mainly used.

[0004] Furthermore, in contrast, in the case of next-generation batteries such as lithium-sulfur batteries (Li-S batteries) or lithium-metal batteries (Li-Metal batteries), the negative electrode can be made of lithium metal itself instead of having a separate current collector. In this case, the mechanical strength of lithium is lower than that of the conventional metal current collector of the negative electrode, and in the manufacturing process or use process of the secondary battery, there is a risk that the welded part of the electrode or the like may be easily deformed or broken.

Summary of the Invention

Problems to be Solved by the Invention

[0005] To address the problems described above, conventional methods have included improving durability by wrapping adhesive tape around the welded area, which is the connection point between the electrode lead and the electrode tab. However, such taping methods have the potential to degrade battery performance due to a chemical reaction between the adhesive tape and the electrolyte, and the manufacturing process is complex.

[0006] Furthermore, even if the welded portion is reinforced using the taping method, the electrode tab connected to the end of the electrode is not protected, making it difficult to completely solve the problem of wire breakage at the relatively weak point between the welded portion and the electrode. [Means for solving the problem]

[0007] A secondary battery according to various embodiments of the present disclosure for achieving the above-described objectives includes an electrode assembly comprising a plurality of electrodes, an electrode tab extending from at least one of the plurality of electrodes, and a separator membrane interposed between the plurality of electrodes; an electrode lead electrically connected to the electrode tab; and a protective portion covering at least a portion of the plurality of electrodes, at least a portion of the electrode tab, and a portion of the electrode lead, wherein at least a portion of the protective portion may be formed of an insulating material that shrinks upon a predetermined energy source.

[0008] For example, at least a portion of the plurality of electrodes covered by the protective portion, at least a portion of the electrode tab, and a portion of the electrode lead may form a continuous or overlapping region.

[0009] In one embodiment, the secondary battery further includes a battery case that houses the electrode assembly and the protective part and has a sealing portion formed on its edge, wherein the protective part can be separated from the sealing portion of the battery case.

[0010] For example, the protective portion includes a first protective portion that covers the bonding area between the electrode tab and the electrode lead, and a second protective portion that covers at least a portion of one of the plurality of electrodes, wherein the area covered by the second protective portion of one of the plurality of electrodes may be 1 / 4 or less of the area of ​​one of the plurality of electrodes.

[0011] In one embodiment, at least a portion of the protective portion includes a laminated first layer and a second layer, the first layer and the second layer may be formed from different materials.

[0012] In one embodiment, the electrode leads of the secondary battery further include an insulating member in one region, and the protective portion can be separated from the insulating member at a predetermined distance.

[0013] In one embodiment, the energy source may include a laser.

[0014] For example, the electrode tab and the electrode lead can be electrically interconnected by the energy source.

[0015] In one embodiment, the protective portion of the secondary battery includes a first protective portion and a second protective portion, the second protective portion covering at least a portion of the plurality of electrodes and at least a portion of the electrode tabs, and the first protective portion covering at least a portion of the second protective portion, at least a portion of the electrode tabs and a portion of the electrode leads, and may be formed of an insulating material that shrinks upon the predetermined energy source.

[0016] A secondary battery according to various embodiments of the present disclosure includes an electrode assembly comprising a plurality of electrodes, an electrode tab extending from at least one of the plurality of electrodes, and a separator membrane interposed between the plurality of electrodes; a battery case housing the electrode assembly and having a sealing portion formed on its edge; and an electrode lead electrically connected to the electrode tab and having at least a portion protruding to the outside of the battery case, wherein the electrode tab and the electrode lead are joined to each other by laser welding, and the joined portion may be covered with an insulating material that shrinks and adheres tightly by the laser welding.

[0017] Devices according to the various embodiments of this disclosure may include secondary batteries according to the various embodiments described above. [Effects of the Invention]

[0018] According to various embodiments of this disclosure, the durability and stability of a secondary battery can be ensured by covering relatively vulnerable parts of the battery through a protective part made of a separate plastic material, thereby preventing the electrode tabs from easily breaking even under external impact.

[0019] Furthermore, the protective unit can be easily attached to the secondary battery using a simple method, replacing the conventional, cumbersome taping process.

[0020] Furthermore, in secondary batteries, not only the weld where the electrode lead and electrode tab are joined, but also the portion of the electrode tab extending from the end of the electrode can be effectively protected.

[0021] Furthermore, the process of attaching the protective section to the secondary battery and welding the electrode leads and electrode tabs can be carried out in a single step, simplifying the manufacturing process and potentially reducing manufacturing costs.

[0022] Furthermore, by laminating two or more layers made of different materials to form a protective section, the protective section can be easily attached while easily ensuring waterproofing, moisture resistance, and electrical insulation properties for the area to be protected. [Brief explanation of the drawing]

[0023] [Figure 1] It is a schematic exploded perspective view of the secondary battery 10 according to an embodiment of the present disclosure.

[0024] [Figure 2a] It is a schematic front view illustrating the state of the secondary battery 10 according to an embodiment of the present disclosure before the protective part is attached.

[0025] [Figure 2b] It is a schematic side view illustrating the state of the secondary battery 10 according to an embodiment of the present disclosure before the protective part is attached.

[0026] [Figure 3a] They are respectively schematic front views for explaining the protective parts attached to the secondary battery 10 according to various embodiments of the present disclosure. [Figure 3b] They are respectively schematic front views for explaining the protective parts attached to the secondary battery 10 according to various embodiments of the present disclosure. [Figure 3c] They are respectively schematic front views for explaining the protective parts attached to the secondary battery 10 according to various embodiments of the present disclosure.

[0027] [Figure 4a] It is a schematic side view of the secondary battery 10 corresponding to FIG. 3a.

[0028] [Figure 4b] It is a schematic side view of the secondary battery 10 corresponding to FIG. 3c.

[0029] [Figure 5a] It is a schematic front view for explaining the protective parts attached to the secondary battery 10 according to various embodiments of the present disclosure. [Figure 5b] It is a schematic front view for explaining the protective parts attached to the secondary battery 10 according to various embodiments of the present disclosure. [Figure 5c]This is a schematic front view illustrating a protective unit attached to a secondary battery 10 according to various embodiments of the present disclosure. [Figure 5d] This is a schematic front view illustrating a protective unit attached to a secondary battery 10 according to various embodiments of the present disclosure. [Modes for carrying out the invention]

[0030] Prior to a detailed description of the present invention, terms and words used herein and in the claims should not be interpreted in a manner limited to their ordinary and dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, based on the principle that inventors may appropriately define terms as concepts in order to best describe their invention. Accordingly, the embodiments described herein and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention; therefore, it should be understood that at the time of filing, there may be a variety of equivalents and modifications that can substitute for them.

[0031] The same reference numerals or symbols in the drawings attached to this specification indicate parts or components that perform substantially the same function. For convenience of explanation and understanding, the same reference numerals or symbols may be used to describe different embodiments. That is, even if components with the same reference numeral are illustrated in multiple drawings, not all of the drawings represent a single embodiment.

[0032] In the following descriptions, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as “contains” or “constitutes” are intended to indicate the existence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and should be understood not to presuppose the existence or possibility of adding one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0033] Furthermore, in the following explanation, terms such as "top," "upper," "lower," "bottom," "side," "front," and "rear" are used based on the direction shown in the drawing, and it should be made clear beforehand that they may be expressed differently if the direction of the object changes.

[0034] Furthermore, in this specification and the claims, terms including ordinal numbers, such as "first," "second," etc., may be used to distinguish between components. Such ordinal numbers are used to distinguish identical or similar components from one another, and the use of such ordinal numbers should not restrict the meaning of the terms. For example, the order of use or arrangement of components combined with such ordinal numbers should not be restricted by the numbers. If necessary, the ordinal numbers may be substituted for each other.

[0035] Embodiments of the present invention will be described below with reference to the attached drawings. However, the concept of the present invention is not limited to the embodiments presented. For example, a person of ordinary skill who understands the concept of the present invention may propose other embodiments that fall within the scope of the present invention through the addition, modification, or deletion of components, and these too can be said to fall within the scope of the present invention. The shapes and sizes of elements in the drawings may be exaggerated for clearer explanation.

[0036] Figure 1 is a schematic exploded perspective view of a secondary battery 10 according to one embodiment of the present disclosure. Figures 2a and 2b are schematic front and side views illustrating the secondary battery 10 according to one embodiment of the present disclosure before the protective parts (e.g., the first protective part 200 in Figure 3c or Figure 5d, and the second protective part 300 in Figure 5d) are attached. In Figures 2a and 2b, for convenience of explanation, the case of the secondary battery 10 (e.g., the case 50 in Figure 1) is not shown.

[0037] Referring to Figures 1 to 2b, the secondary battery 10 according to various embodiments may include an electrode assembly 100 and a battery case 50 that houses the electrode assembly 100.

[0038] According to various embodiments, the electrode assembly 100 may include a plurality of electrodes, electrode tabs 110 (e.g., positive electrode tab 110a and negative electrode tab 110b) extending from at least one of the plurality of electrodes, and a separation membrane interposed between the plurality of electrodes.

[0039] Multiple electrodes may consist of positive and negative electrodes, and for example, they may have a structure in which a positive electrode, a separator membrane, and a negative electrode are sequentially stacked.

[0040] In one embodiment, the negative electrode may include a negative electrode current collector and a negative electrode active material laminated on the negative electrode current collector. For example, the negative electrode may be formed by coating a negative electrode current collector, which is made of a material such as a copper alloy, with a mixture containing at least a negative electrode active material, a conductive material, and a binder.

[0041] On the other hand, in other embodiments, the negative electrode may consist of an integrated lithium metal sheet instead of separately comprising a negative electrode current collector and a negative electrode active material. The lithium metal sheet is a flat sheet member made of lithium metal (lithium or a lithium-containing alloy material), and the negative electrode and the negative electrode tab 110b, which extends from the end of the negative electrode, may all be integrally made of lithium metal.

[0042] When the negative electrode is realized as an integrated unit made of a lithium metal sheet, the negative electrode current collector, which is made of nickel (Ni), aluminum (Al), copper (Cu), etc., can be omitted, which helps to lighten the secondary battery 10 and may also have advantages in terms of high energy density. However, when the negative electrode is made only of lithium metal, there is a problem that the brittle nature of lithium (i.e., the low mechanical strength of lithium) increases the likelihood of physical damage during the manufacturing or use process. According to various embodiments of this disclosure, the negative electrode can be effectively protected and the above-mentioned problems can be easily solved by applying protective parts (e.g., protective part 200 in Figure 3c or protective parts 200, 300 in Figure 5d) to the parts of the negative electrode that are prone to physical damage.

[0043] In embodiments, the positive electrode may include a positive electrode current collector and a positive electrode active material laminated on the positive electrode current collector. For example, the positive electrode may be formed by coating a positive electrode current collector, which is made of a material such as an aluminum alloy, with a mixture comprising at least a positive electrode active material, a conductive material, and a binder. For example, the positive electrode active material may consist of a compound or mixture containing lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or one or more of these. As another example, a sulfur-based material having S-S bonds may be used as the positive electrode active material.

[0044] On the other hand, an insulating separation membrane may be interposed between the positive and negative electrodes. The separation membrane may be configured not only to prevent electrical short circuits between the electrodes but also to allow the electrolyte to be impregnated and ions to pass through. Exemplarily, the separation membrane may be formed from a porous polymer film or a porous nonwoven fabric, etc. However, the separation membranes applied to secondary batteries according to the various embodiments of this disclosure are not necessarily limited to the above materials, and of course, a variety of materials commonly used in secondary batteries may be used.

[0045] According to various embodiments, the electrode tab 110 may include a positive electrode tab 110a extending from the positive electrode end and a negative electrode tab 110b extending from the negative electrode end. The electrode tab 110 may be electrically connected to electrode leads 120 that act as terminals in the secondary battery 10. For example, the positive electrode tab 110a may be formed from aluminum (Al) material, and the negative electrode tab 110b may be formed from copper (Cu) or lithium (Li) material.

[0046] In various embodiments, the secondary battery 10 can include a unidirectional secondary battery in which the positive electrode tab 110a and the negative electrode tab 110b of the electrode tab 110 extend in the same direction, and a bidirectional secondary battery in which the positive electrode tab 110a and the negative electrode tab 110b extend in opposite directions. In the case of a bidirectional secondary battery, a slightly larger space is generally required compared to a unidirectional secondary battery, which can lead to a decrease in energy density. On the other hand, a unidirectional secondary battery may have a relatively high energy density, but because the positive electrode tab 110a and the negative electrode tab 110b are formed in the same direction, a problem may arise where lithium dendrites that may be deposited from the negative electrode as the battery charges and discharges can come into contact with the positive electrode tab 110a, causing a short circuit. However, in the case of the secondary battery 10 according to the various embodiments of this disclosure, the positive electrode tab 110a and the negative electrode tab 110b are physically separated and electrically insulated by the protective part, so that the above-mentioned problems can be effectively prevented even when a bidirectional secondary battery structure is applied.

[0047] On the other hand, the secondary battery 10 may include electrode leads 120 that are electrically connected to an electrode assembly 100 (e.g., electrode tabs 110 of the electrode assembly 100).

[0048] The electrode lead 120 may include a positive electrode lead 120a and a negative electrode lead 120b. For example, the positive electrode lead 120a may be electrically connected to a positive electrode tab 110a extending from the positive electrode, and the negative electrode lead 120b may be electrically connected to a negative electrode tab 110b extending from the negative electrode. For this purpose, the electrode lead 120 may be formed from a conductive metallic material. Exemplarily, the electrode lead 120 may be formed from at least one of nickel, copper, nickel-plated copper, or aluminum.

[0049] The electrode lead 120 and the electrode tab 110 can be electrically connected through various welding methods, including ultrasonic welding, but physical fastening methods such as rivets may also be applied. On the other hand, in one embodiment of this disclosure, if the secondary battery 10 includes a protective part (e.g., the first protective part 200 in Figures 3c, 4b, and 5d), the electrode lead 120 and the electrode tab 110 may be welded by applying a laser to the protective part through a laser welding method. In this case, the protective part can be fixed to the welded portion at the same time as welding by laser irradiation.

[0050] In various embodiments, an insulating member 140 may be placed in a region of the electrode lead 120 (for example, the region corresponding to the sealing portion 150). For example, the insulating member 140 may be formed from a material having insulating and adhesive properties (for example, a thermoplastic resin). The insulating member 140 is joined to the sealing portion 150 of the case 50 while covering a portion of the electrode lead 120, thereby ensuring electrical insulation between the electrode lead 120 and the case 50. Furthermore, the insulating member 140 can seal the case 50 in the region corresponding to the portion of the electrode lead 120 that protrudes from the inside to the outside of the case 50, while simultaneously acting as a buffer to prevent damage to the electrode lead 120 by the sealing portion 150.

[0051] The case 50 may include a housing portion 170, which is an internal space in which the electrode assembly 100 can be housed, and a sealing portion 150, which is a region sealed to shield the electrode assembly 100 in at least a portion of the edge of the housing portion 170. For example, the case 50 may be formed by joining an upper case 52 and a lower case 54. For example, the upper case 52 and the lower case 54 may be joined together by crimping or heat sealing in the region of the sealing portion 150, thereby preventing external foreign matter and moisture from flowing into the electrode assembly 100 located in the housing portion 170.

[0052] Case 50 may include, for example, a pouch-type case formed from a flexible material (e.g., an aluminum laminate sheet). However, the various embodiments of this disclosure are not limited to such pouch-type cases, and may consist of can-type (or rectangular) or cylindrical cases made of metal materials such as aluminum. Depending on the type of case, the electrode assembly 100 can be applied in various forms, such as a stack-type electrode assembly or a jelly-roll type electrode assembly.

[0053] Figures 3a to 3c are schematic front views illustrating protective parts attached to the secondary battery 10 according to various embodiments of the present disclosure.

[0054] Figures 4a and 4b are schematic side views of the secondary battery 10, corresponding to Figures 3a and 3c, respectively. On the other hand, in each of the drawings from Figures 3a to 4b, the case (e.g., case 50 in Figure 1) may be understood to have been omitted for the sake of explanation.

[0055] Referring to Figures 3a to 4b, the secondary battery 10 according to various embodiments may include a first protective section 200 for protecting at least a portion of the electrode leads 120 (e.g., positive electrode lead 120a, negative electrode lead 120b) and at least a portion of the electrode tabs 110 (e.g., positive electrode tab 110a, negative electrode tab 110b).

[0056] In various embodiments, the first protective portion 200 can shrink and adhere closely to a portion of the electrode lead 120 and a portion of the electrode tab 110 when irradiated with heat, UV, ultrasound, laser, etc., and can be formed from a material having electrical insulating and flame-retardant properties. For example, the first protective part 200 may be formed from at least one of the following: polyolefin polymers (e.g., chlorinated polyolefin, crosslinked polyolefin, etc.), fluorine-containing resins (e.g., fluoroelastomer, fluoropolymer), crosslinked polyvinylidene fluoride, crosslinked polyether block amide (PEBA), crosslinked elastomer, polyethylene / polyester composite, silicone rubber, elastomer, polytetrafluoroethylene (PTFE), or polyvinyl chloride (PVC).

[0057] For example, in various embodiments of this disclosure, the first protective portion 200 may be positioned to cover an area including at least the outer surface of the portion where the electrode lead 120 and the electrode tab 110 are in contact, as shown in Figures 3a and 4a. The first protective portion 200 may have a tubular shape to cover the areas to be protected corresponding to the positive electrode tab 110a and the negative electrode tab 110b, respectively. For example, the first protective portion 200 before shrinkage may have a tubular shape with an inner diameter larger than the actual diameter of the overlapping portion of the electrode lead 120 and the electrode tab 110 to be protected. On the other hand, the electrode lead 120 and the electrode tab 110 may not be joined to each other by welding or the like.

[0058] Next, as shown in Figure 3b, in various embodiments, a predetermined energy source may be applied to the first protective part 200 to cause it to contract.

[0059] For example, in one embodiment, a laser may be used as an energy source to shrink the first protective part 200 during the manufacturing of the secondary battery 10. In this case, by irradiating the overlapping portion of the electrode lead 120 and the electrode tab 110 with a laser, the electrode lead 120 and the electrode tab 110 can be fused together. At the same time, energy is applied to the first protective part 200 covering the outer surface of the overlapping portion of the electrode lead 120 and the electrode tab 110, causing it to shrink, and as shown in Figures 3c and 4b, the first protective part 200 can be closely attached to and fixed to the protective portion (i.e., the overlapping portion of the electrode lead 120 and the electrode tab 110). In other words, in various embodiments of this disclosure, by wrapping the first protective part 200 around the outer surface of the electrode lead 120 and the electrode tab 110 before they are fused together, and then irradiating it with a laser, the welding of the electrode lead 120 and the electrode tab 110 and the fixing of the first protective part 200 can be performed simultaneously.

[0060] In this way, the first protective part 200 can prevent tearing or splitting of the fused portion by covering the connecting portion between the electrode lead 120 and the electrode tab 110 on its outer surface, thereby improving the safety of the secondary battery 10.

[0061] For example, the area covered by the first protective part 200 may have a length longer than the length of the joint area between the electrode tab 110 and the electrode lead 120 so as to cover the entire area of ​​the portion where the electrode tab 110 and the electrode lead 120 are joined by welding (i.e., the welded portion). For example, the first protective part 200 may have a length of about 1 mm to 4 mm longer than the joint area. For example, if the joint area between the electrode tab 110 and the electrode lead 120 has a length of about 3 mm, the first protective part 200 may have a length of about 4 mm to 7 mm.

[0062] On the other hand, in other embodiments, the secondary battery 10 may use UV light, heat, ultrasound, or other sources other than lasers as energy sources for shrinking the first protective part 200. For example, the electrode leads 120 and electrode tabs 110 may be welded together as needed, before the first protective part 200 is positioned as shown in Figure 3a, in which case the energy source for shrinking the first protective part 200 is not limited to a laser.

[0063] In one embodiment, the first protective portion 200 is positioned at a predetermined distance from an insulating member 140 formed in a region of the electrode lead 120, thereby preventing the insulating member 140 from being hindered during the sealing process.

[0064] On the other hand, the first protective part 200 applied to the secondary battery 10 according to various embodiments may be configured in a form in which two or more layers having different properties are laminated together. When the first protective part 200 has a laminated form of two or more layers, for example, the inner layer may be formed from a material with excellent shrinkage properties, and the outer layer may be formed from a material with excellent waterproof, moisture-proof, and / or electrical insulation properties.

[0065] Figures 5a to 5d are schematic front views illustrating protective parts attached to the secondary battery 10 according to various embodiments of the present disclosure.

[0066] Referring to Figure 5a, the secondary battery 10 according to various embodiments may include a second protective section 300 that integrally covers the electrodes (e.g., positive electrode and negative electrode) and electrode tabs 110 (e.g., positive electrode tab 110a and negative electrode tab 110b) extending from each electrode.

[0067] In the embodiment, the second protective portion 300 may have a shape that includes two holes on one side corresponding to the respective electrode tabs 110 (i.e., the positive electrode tab 110a and the negative electrode tab 110b) and one large hole on the other side corresponding to the body portion of the electrode, so as to integrally cover a portion of the electrode and a portion of the electrode tab 110 extending from the end of the electrode.

[0068] For example, the second protective part 300 may be formed from at least one material, such as polypropylene (PP) or polyethylene (PE). However, it is not limited to such materials, and a variety of polymeric plastic materials having rigidity and weight properties that can protect the ends of the electrodes may be used. As an example, the second protective part 300 may be formed from a plastic material that has the property of shrinking in response to an energy source such as heat, similar to the first protective part 200. As another example, the second protective part 300 may be formed from a material that does not have thermal shrinkage properties but is harder than the first protective part 200.

[0069] On the other hand, in one embodiment, the second protective part 300 can be fixed to the electrode assembly 100 by a separate component such as a clip, while being placed over a portion of the electrode and a portion of the electrode tab 110 extending from the end of the electrode. Alternatively, the first protective part 200, which is connected to the second protective part 300, may be indirectly fixed to the electrode assembly 100 by being fixed to the bonding area.

[0070] On the other hand, in the second protective section 300, the area (or length) of the region covering the electrode body may be configured to cover only about 1 / 4 or less of the total area (or length) of the electrode body.

[0071] This allows the secondary battery 10 to effectively protect the next most vulnerable point to external impact after the weld (i.e., the portion connecting the electrode end to the electrode tab 110) while preventing a decrease in energy efficiency due to an increase in the weight of auxiliary materials by unnecessarily covering parts that are not vulnerable to external impact (e.g., the lower end of the electrode body).

[0072] Referring to Figures 5b to 5d, in yet another embodiment, the secondary battery 10 may include a second protective unit 300 and a first protective unit 200, respectively.

[0073] For example, as shown in Figures 5b and 5c, with the second protective part 300 covering a portion of the electrodes of the secondary battery 10 and a portion of the electrode tab 110, the first protective part 200 can be positioned so as to include at least a portion of the second protective part 300 and the overlapping portion of the electrode tab 110 and the electrode lead 120. Then, an energy source can be applied to contract the first protective part 200. As a result, the first protective part 200 can be fixed in close contact with the covered area, such as a portion of the second protective part 300 and the overlapping portion of the electrode tab 110 and the electrode lead 120, and thereby the second protective part 300 can also be indirectly fixed to a designated portion of the electrode assembly 100, such as the electrode tab 110.

[0074] As described above, in order to obtain the effect that the second protective part 300 is also fixed by the close contact and fixing of the first protective part 200, in the secondary battery 10 according to one embodiment of the present disclosure, the areas protected by the first protective part 200 and the second protective part 300 must overlap in at least a portion.

[0075] On the other hand, if a laser is used as the energy source for shrinking the first protective part 200, there is an advantage that welding to melt the electrode lead 120 and electrode tab 110 can be performed simultaneously while fixing the first protective part 200 and the second protective part 300 by irradiating them with the laser. However, the energy source for shrinking the first protective part 200 is not limited to such a laser. For example, in one embodiment, welding of the electrode lead 120 and electrode tab 110 is performed after the second protective part 300 is placed over a part of the electrode and a part of the electrode tab 110. After that, the first protective part 200 may be placed over a part of the second protective part 300 and the welded area, and then the first protective part 200 may be fixed (and the second protective part 300 is fixed by fixing the first protective part 200) using various energy sources such as heat and UV.

[0076] In various embodiments of this disclosure, the secondary battery 10 may include a pouch-type secondary battery having a structure in which an electrode assembly is housed inside a flexible pouch that is capable of charging and discharging, a prismatic secondary battery in which an electrode assembly is housed inside a prismatic case having a predetermined rigidity, or a cylindrical secondary battery in which an electrode assembly is housed inside a cylindrical case. In this specification, the description has been based on a secondary battery in which pouch-type secondary batteries are stacked in one direction, but this is merely an illustrative description and the various embodiments of the present invention are not limited to such pouch-type secondary batteries.

[0077] The secondary battery 10, and battery modules or battery packs containing the same, according to various embodiments of this disclosure, can be applied to a variety of devices. For example, devices to which the secondary battery 10 according to various embodiments of this disclosure can be applied may include, but are not limited to, means of transport such as electric bicycles, electric vehicles, and hybrid vehicles, and can be applied to a variety of types of devices that can use the secondary battery 10.

[0078] On the other hand, although terms indicating direction such as "up" and "down" are used in this specification, such terms are merely for the convenience of explanation, and it is obvious to an ordinary person skilled in the art that they can change depending on the position of the object in question, the position of the observer, etc.

[0079] Although various embodiments of the present invention have been described in detail above, it will be obvious to anyone with average knowledge of the art that the scope of the present invention is not limited thereto, and that various modifications and variations are possible without departing from the technical idea of ​​the present invention as described in the claims. Furthermore, some components may be omitted in the embodiments described above, and each embodiment may be combined with one another.

Claims

1. It is a secondary battery, An electrode assembly comprising a plurality of electrodes, an electrode tab extending from at least one of the plurality of electrodes, and a separation membrane interposed between the plurality of electrodes, An electrode lead electrically connected to the electrode tab, A protective portion covering at least a portion of the plurality of electrodes, at least a portion of the electrode tab, and a portion of the electrode lead, A secondary battery in which at least a portion of the protective part is formed of an insulating material that shrinks in response to a predetermined energy source.

2. The battery case further includes the electrode assembly and the protective part, and has a sealing portion formed on its edge. The secondary battery according to claim 1, wherein the protective portion is separated from the sealing portion of the battery case.

3. The aforementioned protective part is A first protective portion covering the bonding area between the electrode tab and the electrode lead, It includes a second protective portion that covers at least a portion of one of the plurality of electrodes, The secondary battery according to claim 1, wherein the area of ​​one of the plurality of electrodes covered by the second protective portion is 1 / 4 or less of the area of ​​one of the plurality of electrodes.

4. The secondary battery according to claim 1, wherein at least a portion of the plurality of electrodes covered by the protective portion, at least a portion of the electrode tabs, and a portion of the electrode leads form a continuous or overlapping region.

5. At least a portion of the protective portion includes a first layer and a second layer that are stacked together. The secondary battery according to claim 1, wherein the first layer and the second layer are formed from different materials.

6. The electrode lead further includes an insulating member in one region, The secondary battery according to claim 1, wherein the protective portion is separated from the insulating member at a predetermined distance.

7. The secondary battery according to claim 1, wherein the energy source includes a laser.

8. The protective part includes a first protective part and a second protective part. The second protective portion covers at least a portion of the plurality of electrodes and at least a portion of the electrode tabs, The secondary battery according to claim 1, wherein the first protective portion covers at least a portion of the second protective portion, at least a portion of the electrode tab, and a portion of the electrode lead, and is formed of an insulating material that shrinks due to the predetermined energy source.

9. The secondary battery according to claim 1, wherein the electrode tab and the electrode lead are electrically interconnected by the energy source.

10. It is a secondary battery, An electrode assembly comprising a plurality of electrodes, an electrode tab extending from at least one of the plurality of electrodes, and a separation membrane interposed between the plurality of electrodes, A battery case that houses the electrode assembly and has a sealing portion formed on its edge, The electrode tab is electrically connected to the electrode lead, and at least a portion of it protrudes outside the battery case, A secondary battery in which the electrode tab and the electrode lead are joined together by laser welding, and the joined portion is covered with an insulating material that shrinks and adheres tightly due to the laser welding.

11. A device comprising a secondary battery according to any one of claims 1 to 10.

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