Current collector, electrode, and secondary battery

Abstract

A current collector according to the present invention comprises: a pair of metal layers; and an intermediate layer positioned between the pair of metal layers and made of a polymer material, wherein the intermediate layer has accommodation recesses that are concave inward, and the pair of metal layers include a metal layer body in contact with the intermediate layer and connection protrusions protruding from the metal layer body so as to be accommodated in the accommodation recesses.

Description

Current collectors, electrodes, and secondary batteries

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0193110 filed on December 20, 2024, and all contents disclosed in the document of said Korean Patent Application are incorporated herein as part of this specification.

[0003] Technology field

[0004] The present invention relates to a current collector, an electrode, and a secondary battery. More specifically, the invention relates to a current collector comprising a pair of metal layers and a polymer intermediate layer positioned between them, an electrode comprising the same, and a secondary battery comprising the same.

[0005] In secondary batteries, the current collector serves as a channel through which electricity generated by the active material layer can travel. Conventional current collectors can be formed from thin metal plates. However, since metal is considerably heavy, the use of a metal current collector can increase the weight of the secondary battery. In particular, an increase in the weight of the secondary battery can lead to a decrease in fuel efficiency when the battery is used in vehicles. To overcome this, a new concept of current collector is being developed.

[0006] A new concept current collector (hereinafter referred to as the current collector) can be provided with an intermediate layer of polymer material positioned between a pair of metal layers. Since polymers have a lower weight than metals, the weight of the current collector can be reduced.

[0007] However, since the intermediate layer of the current collector has low electrical conductivity, it is necessary to electrically connect a pair of metal layers located on both sides of the intermediate layer. In particular, as the current collector is formed by stacking multiple electrodes, a portion of the stacked multiple current collectors located in an uncoated area where the active material layer is not coated can be joined together. By electrically connecting a pair of metal layers while joining portions of the multiple current collectors together, the problem of time delay caused by having a separate process for electrically connecting a pair of metal layers can be resolved.

[0008] At this time, a desirable structural design is required to electrically connect a pair of metal layers while combining parts of multiple current collectors.

[0009] The aforementioned background technology is one that the inventor possessed or acquired in the process of deriving the contents of the disclosure of the present application, and it cannot be considered as prior art disclosed to the general public prior to the filing of this application.

[0010] The present invention was devised to solve the above problems, and the objective of the present invention is to provide a current collector that facilitates connecting a pair of metal layers of the current collector to each other.

[0011] The technical problems to be solved in this document are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below.

[0012] A current collector according to one embodiment of the present invention comprises a pair of metal layers and an intermediate layer having a polymer material located between the pair of metal layers, wherein the intermediate layer has an inwardly concave receiving groove, and the pair of metal layers includes a metal layer body in contact with the intermediate layer and a connecting projection protruding from the metal layer body to be received in the receiving groove.

[0013] The receiving groove can be located adjacent to the end of the middle layer.

[0014] A pair of metal layers and an intermediate layer define a retaining region where the active material layer is located and a non-retaining region where the active material layer is not located, and the receiving groove can be located in the non-retaining region.

[0015] Multiple receiving grooves are provided, and some of the multiple receiving grooves may be located in a maintenance area.

[0016] The receiving groove may not have a corner at the end.

[0017] The receiving groove may have a spherical end.

[0018] A pair of metal layers is defined as a first metal layer and a second metal layer, and the receiving groove may include a first receiving groove facing the first metal layer and a second receiving groove facing the second metal layer.

[0019] The first receiving groove can be configured so as not to come into contact with the second receiving groove.

[0020] The first receiving grooves are provided and arranged in multiple numbers, the second receiving grooves are provided and arranged in multiple numbers, and the multiple first receiving grooves and multiple second receiving grooves can be arranged alternately with each other.

[0021] The current collector is configured to have its thickness reduced by rolling, and a connecting projection included in a first metal layer is defined as a first connecting projection, and a connecting projection included in a second metal layer is defined as a second connecting projection, and the first connecting projection and the second connecting projection may be positioned closer than the thickness reduced by rolling so as to meet when the current collector is rolled.

[0022] The first connecting projection and the second connecting projection can be configured to be connected to each other by ultrasonic welding.

[0023] A plurality of receiving grooves are provided, and a plurality of connecting protrusions are provided to correspond to the plurality of receiving grooves. A pair of metal layers and an intermediate layer define a welding area where the plurality of receiving grooves are located, and the plurality of connecting protrusions can be provided to have a larger volume than the intermediate layer in the welding area.

[0024] The metal layer can be bonded to the intermediate layer by deposition.

[0025] The metal layer may include aluminum material.

[0026] The intermediate layer may include at least one of PET (Polyethylene Terephthalate) or PP (Polypropylene) material.

[0027] An electrode according to one embodiment of the present invention comprises an active material layer and a current collector to which the active material layer is coupled, and the current collector comprises a metal layer and an intermediate layer coupled to the metal layer and having a polymer material, the intermediate layer has a receiving groove that is concave inwardly, and the metal layer comprises a metal layer body in contact with the intermediate layer and a connecting projection that protrudes from the metal layer body to be received in the receiving groove.

[0028] The receiving groove can be located adjacent to the end of the middle layer.

[0029] The metal layer and the intermediate layer are defined with a retaining region that overlaps with the active material layer and a non-retaining region that does not overlap with the active material layer, and the receiving groove can be located in the non-retaining region.

[0030] Multiple receiving grooves are provided, and some of the multiple receiving grooves may be located in a maintenance area.

[0031] A secondary battery according to one embodiment of the present invention includes an electrode and a battery case in which the electrode is received, and includes an active material layer and a current collector to which the active material layer is combined, wherein the current collector includes a metal layer and an intermediate layer combined with the metal layer and having a lower density than the metal layer, wherein the intermediate layer has an inwardly concave receiving groove, and the metal layer includes a metal layer body in contact with the intermediate layer and a connecting projection protruding from the inner layer body to be received in the receiving groove.

[0032] A current collector according to one embodiment of the present invention comprises an intermediate layer having a receiving groove and a pair of metal layers having connecting protrusions received in the receiving groove, so that the pair of metal layers can be easily connected by bringing them closer together.

[0033] A current collector according to one embodiment of the present invention has a receiving groove rather than a hole, so that the current collector can be structurally stable.

[0034] In one embodiment of the present invention, the end of the receiving groove is not angled, so it can facilitate the deposition of a metal layer.

[0035] In one embodiment of the present invention, the metal layer is provided with a larger volume than the intermediate layer in the portion where the receiving groove is located, so that the portion where the receiving groove is located can be structurally stable.

[0036] The electrode and secondary battery of one embodiment according to the present invention can have the above effects by including the above current collector.

[0037] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0038] FIG. 1 is an assembly diagram of a secondary battery according to a first embodiment of the present invention.

[0039] Figure 2 is a cross-sectional view of the current collector of the electrode assembly shown in Figure 1.

[0040] Figure 3 is a conceptual diagram illustrating the process of forming the entire house shown in Figure 2.

[0041] FIG. 4 is a cross-sectional view illustrating that an electrode is formed by bonding an active material layer to the current collector shown in FIG. 2.

[0042] Figure 5 is a cross-sectional view showing the electrode shown in Figure 4 rolled.

[0043] FIG. 6 is a cross-sectional view showing an electrode lead coupled to the electrode shown in FIG. 5.

[0044] FIG. 7 is a cross-sectional view illustrating that a plurality of electrodes shown in FIG. 6 are provided and coupled to electrode leads to form an electrode assembly.

[0045] FIG. 8 is a cross-sectional view of a current collector according to a second embodiment of the present invention.

[0046] FIG. 9 is a cross-sectional view of a current collector according to a third embodiment of the present invention.

[0047] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0048] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0049] Furthermore, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0050] The various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments.

[0051] In relation to the description of the drawings, similar reference numerals may be used for similar or related components.

[0052] The singular form of the noun corresponding to the item may include one or multiple items, unless the relevant context clearly indicates otherwise.

[0053] In this document, each of the phrases such as "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0054] The term "and / or" includes a combination of multiple related described components or any of the multiple related described components.

[0055] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish a component from another corresponding component and do not limit the components in other aspects (e.g., importance or order).

[0056] Where any (e.g., 1st) component is referred to as "coupled" or "connected" to another (e.g., 2nd) component, with or without the terms "functionally" or "communicationly," it means that said any component may be connected to said other component directly (e.g., via a wire), wirelessly, or through a third component.

[0057] Terms such as "include" or "have" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in this document, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0058] When it is said that a component is "connected," "combined," "supported," or "in contact" with another component, this includes not only cases where the components are directly connected, combined, supported, or in contact, but also cases where they are indirectly connected, combined, supported, or in contact through a third component.

[0059] When it is said that a component is located "on" another component, this includes not only cases where one component is in contact with the other, but also cases where another component exists between the two components.

[0060] Meanwhile, terms such as "up-and-down direction," "downward side," and "front-backward direction" used in the following description are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0061] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0062] First embodiment

[0063] FIG. 1 is an assembly diagram of a secondary battery (B) according to a first embodiment of the present invention.

[0064] Referring to FIG. 1, a secondary battery (B) according to the first embodiment of the present invention will be described.

[0065] A secondary battery (B) may be provided to generate electricity. In the first embodiment, the secondary battery (B) is described assuming a pouch-type secondary battery (B), but the secondary battery (B) may be cylindrical or prismatic as needed. As shown in FIG. 1, the secondary battery (B) may include a battery case (100) and an electrode assembly (EA).

[0066] A battery case (100) may be formed from a pouch film. A receiving portion (110) may be provided in a part of the pouch film by stretching the pouch film by a press. The receiving portion (110) may have an electrode receiving space (100S) in which an electrode assembly (EA) is received. Furthermore, a side portion (120) extending from the receiving portion (110) may be formed on the outer side of the receiving portion (110). In other words, the battery case (100) may include the receiving portion (110) and the side portion (120). As shown in FIG. 1, the receiving portion (110) may be provided in pairs and arranged to face each other. However, the receiving portion (110) may be provided as a single unit if necessary.

[0067] A folding portion (123) may be provided to be folded between a pair of receiving portions (110). By folding the folding portion (123), the pair of receiving portions (110) may face each other. That is, the side portion (120) may include a folding portion (123) located between a pair of receiving portions (110). In addition to the folding portion (123), the side portion (120) may include a lead sealing portion (121) and a degas sealing portion (122). The lead sealing portion (121) may be a portion extending from the edge that overlaps with the electrode lead (500) with respect to the receiving portion (110). As the pair of receiving portions (110) are positioned to face each other, the lead sealing portion (121) may face another corresponding lead sealing portion (121). A lead film (510) may be positioned between a pair of facing lead sealing portions (121). A degas sealing portion (122) may extend from the corner where the lead sealing portion (121) and the folding portion (123) are not formed with respect to the receiving portion (110). The degas sealing portion (122) may face another corresponding degas sealing portion (122) as the pair of receiving portions (110) are positioned to face each other. Each of the facing side portions (120) may fuse together when heat and pressure are applied to seal the receiving portion (110).

[0068] The electrode assembly (EA) may include a plurality of electrodes (E), a separator (400) interposed between the plurality of electrodes (E), and / or an electrode lead (500) coupled to the plurality of electrodes (E). The electrode lead (500) may be positioned between a pair of lead sealing portions (121). Furthermore, a lead film (510) may be coupled to the electrode lead (500) to be coupled to the lead sealing portion (121). The electrode lead (500) may be made of a metal material, the inner side of the lead sealing portion (121) may be made of a polymer material, and the lead film (510) may be made of a polymer material. Since the affinity between the lead film (510) and the lead sealing portion (121) is higher than the affinity between the electrode lead (500) and the lead sealing portion (121), the lead film (510) can enhance the sealing effect between the electrode lead (500) and the lead sealing portion (121).

[0069] A plurality of electrodes (E) may be provided with an active material layer (200) that is directly involved in the production of electricity and a current collector (300) that transmits the electricity produced by the active material layer (200). Generally, the current collector (300) may be formed as a thin metal plate. However, a current collector (300) made solely of metal is heavy, and if a heavy current collector (300) is included in each electrode (E), the weight of the plurality of electrodes (E) may become even heavier. As a result, the weight of the object equipped with the secondary battery (B) may increase. For example, if the weight of the secondary battery (B) increases, the weight of the vehicle equipped with the secondary battery (B) may increase. In the case of a vehicle, since fuel efficiency decreases as weight increases, it is necessary to reduce the weight of the current collector (300). To this end, a new type of current collector (300) described below may be provided. Further explanation will be provided below with reference to the drawings.

[0070] FIG. 2 is a cross-sectional view of a current collector (300) of an electrode assembly (EA) illustrated in FIG. 1. FIG. 3 is a conceptual diagram illustrating the process of forming the current collector (300) illustrated in FIG. 2. FIG. 4 is a cross-sectional view illustrating that an electrode (E) is formed by combining an active material layer (200) with the current collector (300) illustrated in FIG. 2. FIG. 5 is a cross-sectional view illustrating that the electrode (E) illustrated in FIG. 4 is rolled. FIG. 6 is a cross-sectional view illustrating that an electrode lead (500) is combined with the electrode (E) illustrated in FIG. 5. FIG. 7 is a cross-sectional view illustrating that an electrode assembly (EA) is formed by providing a plurality of electrodes (E) illustrated in FIG. 6 and combining them with electrode leads (500).

[0071] Referring to FIGS. 2 to 7, a current collector (300) and an electrode (E) including the current collector (300) according to the first embodiment of the present invention will be described.

[0072] As illustrated in FIG. 2, the current collector (300) may include a pair of metal layers (310) and an intermediate layer (320) positioned between the pair of metal layers (310). In this case, the intermediate layer (320) may have a polymer material. However, if necessary, the intermediate layer (320) may have a material other than a polymer material, provided that it is lighter in density than the metal layers (310). Furthermore, the metal layers (310) may be provided as a single layer rather than a pair if necessary. Accordingly, the current collector (300) may have a lighter density by including the intermediate layer (320) than by being formed only of metal layers (310). For reference, the current collector (300) in the present disclosure may refer to the current collector (300) when the secondary battery (B) is fully formed, or it may refer to the current collector (300) provided before the secondary battery (B) is fully formed. The meaning of the entire house (300) can be interpreted appropriately depending on the context.

[0073] Additionally, the metal layer (310) may include aluminum or copper. Such materials are desirable in terms of reactivity with the active material and are relatively light among metals, thus reducing the weight of the current collector (300). Furthermore, the intermediate layer (320) may include at least one of PET (Polyethylene Terephthalate) or PP (Polypropylene). Since PET and PP have good moldability, it may be easy to form the receiving groove (322H) described later.

[0074] As shown in FIG. 3, the metal layer (310) can be bonded to the intermediate layer (320) by deposition. For example, the metal layer (310) can be formed by sputtering.

[0075] As illustrated in FIG. 4, an electrode (E) can be formed by forming an active material layer (200) on a metal layer (310) of a current collector (300). The active material layer (200) may include an active material, a binder, and / or a conductive material. The electrode (E) may form a positive electrode and a negative electrode, respectively, and may be stacked alternately with each other as illustrated in FIG. 7. A plurality of separators (400) may be interposed between the stacked electrodes (E) to prevent a short circuit from occurring when the positive and negative electrodes meet. At this time, the separators (400) may be provided in a plurality so as to be individually positioned between the electrodes (E), but if necessary, a single separator (400) may be positioned to pass between the electrodes (E) in a zigzag shape.

[0076] As illustrated in FIG. 4, the electrode (E) may include a retaining region (A1) where the active material layer (200) is located and a non-retaining region (A2) where the active material layer (200) is not located. In other words, a retaining region (A1) where the active material layer (200) is located and a non-retaining region (A2) where the active material layer (200) is not located may be defined in a pair of metal layers (310) and an intermediate layer (320). At this time, the current collector (300) located in the non-retaining region (A2) may be referred to as the electrode (E) tab. Only the current collector (300) is located in the non-retaining region (A2), so that when multiple electrodes (E) are stacked, the current collectors (300) of adjacent non-retaining regions (A2) can be joined together. At this time, the adjacent current collectors (300) located in the non-retaining region (A2) can be joined so as to be electrically connected to each other. Electricity generated from multiple electrodes (E) can be transferred to the outside of the secondary battery (B) in one go through the non-transparent region (A2) of the combined current collector (300). As shown in FIG. 7, the current collector (300) of the multiple non-transparent region (A2) can be combined with the electrode lead (500). At this time, the electrode lead (500) and the current collector (300) can be arranged in a line and welded by ultrasonic welding. When ultrasonic welding is performed on the current collector (300), the intermediate layer (320) located between a pair of metal layers (310) of the current collector (300) is melted, and a passage can be formed through which the pair of metal layers (310) can be connected to each other. However, if necessary, the electrode lead (500) and the current collector (300) may be combined by an energy generating means other than ultrasonic welding. Furthermore, as needed, welding may be performed in a separated manner in which the electrode lead (500) and the current collector (300) are not welded in a single process, but rather a plurality of current collectors (300) are welded first and then welded with the electrode lead (500).

[0077] Referring to the illustration in FIG. 2, a pair of metal layers (310) of a current collector (300) need to be connected to each other to form a completed secondary battery (B). Each pair of metal layers (310) can serve as a channel for moving electricity transferred from the active material layer (200) that is connected to each other. At this time, if the intermediate layer (320) is made of a polymer material, it has low electrical conductivity, which can hinder the flow of electricity between the pair of intermediate layers (320). As previously explained, since electricity formed at one electrode (E) can be moved outward through the electrode lead (500), the electricity moving through each of the pair of metal layers (310) needs to be gathered together and moved toward the electrode lead (500). That is, a pair of metal layers (310) need to be electrically connected to each other to form a completed secondary battery (B). However, when attempting to connect a pair of metal layers (310) to each other by stacking multiple electrodes (E) and performing ultrasonic welding with electrode leads (500), the energy used for ultrasonic welding may not be sufficient, and thus the pair of metal layers (310) may not be sufficiently connected. The first embodiment of the present invention aims to solve such a problem.

[0078] As illustrated in FIG. 2, the first embodiment of the present invention may have an intermediate layer (320) having an inwardly concave receiving groove (322H). In other words, an intermediate layer body (321) in which the receiving groove (322H) is formed may be formed in the intermediate layer (320). At this time, a pair of metal layers (310) may include a metal layer body (311) in contact with the intermediate layer (320) and a connecting projection (312) protruding from the metal layer body (311) to be received in the receiving groove (322H). By forming the connecting projection (312), the pair of metal layers (310) can be positioned closer to each other than when the intermediate layer (320) has a substantially flat shape. Accordingly, the pair of metal layers (310) may be easily connected to each other by ultrasonic welding.

[0079] At this time, the receiving groove (322H) may be located adjacent to the end of the intermediate layer (320). In other words, the receiving groove (322H) may be located in the non-receiving area (A2). By having the receiving groove (322H) located in the non-receiving area (A2), as described above, when the electrode lead (500) and the current collector (300) are ultrasonically welded, the ultrasonically welding can be performed at the portion where the connecting projection (312) is located, thereby facilitating connection between a pair of metal layers (310). Additionally, the receiving groove (322H) may be provided in multiple numbers, and some of the multiple receiving grooves (322H) may be located in the retaining area (A1). Accordingly, when energy is transmitted by ultrasonic welding to the unoccupied area (A2) of the entire house (300), energy is also transmitted to the connecting projection (312) located in the receiving groove (322H) located in the retaining area (A1) adjacent to the unoccupied area (A2), so that a pair of metal layers (310) located in the retaining area (A1) can also be joined together.

[0080] For convenience of explanation, a pair of metal layers (310) may be defined as a first metal layer (310a) and a second metal layer (310b). Based on FIG. 2, the first metal layer (310a) may be a metal layer (310) located on the upper side, and the second metal layer (310b) may be a metal layer (310) located on the lower side. Accordingly, the receiving groove (322H) may include a first receiving groove (322Ha) facing the first metal layer (310a) and a second receiving groove (322Hb) facing the second metal layer (310b). Furthermore, the connecting projection (312) may include a first connecting projection (312a) included in the first metal layer (310a) and a second connecting projection (312b) included in the second metal layer (310b). And, the metal layer body (311) may include a first metal layer body (311a) included in the first metal layer (310a) and a second metal layer body (311b) included in the second metal layer (310b).

[0081] As defined above, to reiterate the features of the first embodiment of the present invention, the first connecting projection (312a) and the second connecting projection (312b) can be configured to be connected to each other by ultrasonic welding.

[0082] The first receiving groove (322Ha) may be configured so as not to come into contact with the second receiving groove (322Hb). As will be described below, the thickness of the electrode (E) may be reduced as it undergoes a rolling process. Here, the fact that the first receiving groove (322Ha) and the second receiving groove (322Hb) do not come into contact may be assumed to be a situation prior to rolling. The fact that the first receiving groove (322Ha) and the second receiving groove (322Hb) do not come into contact may mean that the receiving groove (322H) may not be a hole. As previously mentioned, if the connection between the first metal layer (310a) and the second metal layer (310b) is a problem, as a solution thereto, a hole may be formed in the intermediate layer (320) so that the first metal layer (310a) and the second metal layer (310b) can be connected. However, if a hole is formed, the structural stability of the intermediate layer (320) is reduced, and accordingly, the structural stability of the current collector (300) may be reduced. If the structural stability of the current collector (300) is reduced, the possibility of producing defective products during the mass production of the current collector (300) may increase. In the first embodiment of the present invention, a receiving groove (322H) rather than a hole is formed in the intermediate layer (320), thereby facilitating the connection between the first metal layer (310a) and the second metal layer (310b) without significantly reducing structural stability.

[0083] At this time, as illustrated in FIG. 2, the first receiving grooves (322Ha) may be arranged in a plurality, and the second receiving grooves (322Hb) may be arranged in a plurality. In addition, the plurality of first receiving grooves (322Ha) and the plurality of second receiving grooves (322Hb) may be arranged alternately with each other. Accordingly, the plurality of first connecting protrusions (312a) received in the plurality of first receiving grooves (322Ha) and the plurality of second connecting protrusions (312b) received in the plurality of second receiving grooves (322Hb) may be arranged alternately with each other. If the first connecting protrusions (312a) and the second connecting protrusions (312b) are arranged to face each other, the intermediate layer (320) at the portion where the connecting protrusions (312) are located may be located between the first connecting protrusions (312a) and the second connecting protrusions (312b). This configuration reduces the thickness of the intermediate layer (320), which can lower the structural stability of the intermediate layer (320). By arranging the first connecting protrusion (312a) and the second connecting protrusion (312b) alternately, sufficient thickness of the intermediate layer (320) overlapping the first connecting protrusion (312a) and the second connecting protrusion (312b) can be secured, thereby improving the structural stability of the intermediate layer (320). Furthermore, as the first connecting protrusion (312a) and the second connecting protrusion (312b) melt through ultrasonic welding, the connection between adjacent connecting protrusions (312) can be facilitated, thus facilitating the bonding between the first metal layer (310a) and the second metal layer (310b). If the first connecting projection (312a) and the second connecting projection (312b) face each other, it may be difficult to connect with other adjacent first connecting projections (312a) and second connecting projections (312b). Therefore, when compared to such a structure, the connection between the first metal layer (310a) and the second metal layer (310b) in the first embodiment of the present invention may be relatively easy.

[0084] As shown in FIG. 4, an active material layer (200) can be applied to the current collector (300). And, as shown in FIG. 5, the electrode (E) can be rolled. At this time, the current collector (300) can be configured so that its thickness is reduced by rolling. Before rolling, as shown in FIG. 4, the first connecting projection (312a) and the second connecting projection (312b) can be spaced apart from each other. However, after rolling, as shown in FIG. 5, the first connecting projection (312a) and the second connecting projection (312b) can come into contact with each other. In other words, the first connecting projection (312a) and the second connecting projection (312b) can be positioned closer than the thickness of the current collector (300) that is reduced by rolling so that they meet when the current collector (300) is rolled.

[0085] A pair of metal layers (310) and an intermediate layer (320) can define a welding area where a plurality of receiving grooves (322H) are located. A plurality of connecting protrusions (312) can be provided to have a larger volume than the intermediate layer (320) in the welding area. As previously mentioned, the intermediate layer (320) may be a polymer material, and the metal layer (310) may be a metal material. Since metal has a higher rigidity than polymer, the structural rigidity can be increased by having a larger volume of the metal layer (310) in the welding area.

[0086] At this time, corners may not be provided at the end of the receiving groove (322H). For example, the end of the receiving groove (322H) may have a spherical shape. If corners are formed in the receiving groove (322H), it may be difficult to deposit the metal layer (310) on the intermediate layer (320) by deposition as shown in FIG. 3. In the first embodiment of the present invention, corners are not formed in the receiving groove (322H), thereby facilitating the deposition of the metal layer (310) into the receiving groove (322H). However, if necessary, the receiving groove (322H) may not have corners completely formed, but may not have the shape of a rectangular receiving groove (322H), so that the corners are formed less.

[0087] As illustrated in FIG. 6, when the electrode (E) is coupled to the electrode lead (500), the first metal layer (310a) and the second metal layer (310b) may be connected by a connecting bridge (313). The connecting bridge (313) may be formed by combining the first connecting projection (312a) and the second connecting projection (312b).

[0088] More specifically, as shown in FIG. 7, the electrode (E) is coupled to the electrode lead (500), so that the current collector (300) of each of the plurality of electrodes (E) can be connected to the electrode lead (500). Then, the connecting projection (312) received in the receiving groove (322H) of each current collector (300) melts to form a connecting bridge (313), thereby electrically connecting the electrode lead (500) and the electrode (E).

[0089] The first embodiment and other embodiments are described below. Content common to the first embodiment will be omitted as much as possible, and the other embodiments will be described focusing on the differences. In other words, it is obvious that if content not explained in the other embodiments is necessary, it can be supplemented through the content of the first embodiment.

[0090] 2nd embodiment

[0091] FIG. 8 is a cross-sectional view of a current collector (300-1) according to a second embodiment of the present invention.

[0092] Referring to FIG. 8, a receiving groove (322H-1) and a connecting projection (312-1) according to a second embodiment of the present invention will be described.

[0093] The second embodiment differs from the first embodiment in that the first receiving groove (322Ha-1) and the second receiving groove (322Hb-1), and the first connecting projection (312a-1) and the second connecting projection (312b-1) are provided as a single unit. The first connecting projection (312a-1) and the second connecting projection (312b-1) can be positioned close to the first metal layer (310a-1) and the second metal layer (310b-1).

[0094] The first receiving groove (322Ha-1) may extend in the longitudinal direction of the collector (300-1). The second receiving groove (322Hb-1) may also extend in the longitudinal direction of the collector (300-1). The first receiving groove (322Ha-1) and the second receiving groove (322Hb-1) may be configured to face each other.

[0095] Third embodiment

[0096] FIG. 9 is a cross-sectional view of a current collector (300-2) according to a third embodiment of the present invention.

[0097] Referring to FIG. 9, a receiving groove (322H-2) and a connecting projection (312a-2) including a metal layer according to a third embodiment of the present invention will be described.

[0098] The third embodiment differs from the first embodiment in that the receiving groove (322H-2) and the connecting projection (312) are formed only on one side of the current collector (300).

[0099] More specifically, the first metal layer (310a-2) may include a connecting projection (312a-2). However, the second metal layer (310b-2) may not include a connecting projection (312a-2).

[0100] At this time, the receiving groove (322H-2) and the connecting projection (312a-2) are formed to be longer than those of the first embodiment, so that the first metal layer (310a-2) and the second metal layer (310b-2) are brought closer together.

[0101] Unless explicitly stated otherwise, the embodiments described above may be combined with other embodiments. Alternatively, unless explicitly limited in the combination of any embodiment with another, it should be considered that combinations between embodiments are possible. Any combination of any embodiment with another embodiment is deemed to be disclosed herein.

[0102] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0103] [Explanation of the symbol]

[0104] B: Secondary battery

[0105] 100: Battery case

[0106] 100S: Electrode receiving space

[0107] 110: Reception Department

[0108] 120: Side

[0109] 121: Lead sealing part

[0110] 122: Digas sealing part

[0111] 123: Folding part

[0112] EA: Electrode assembly

[0113] E: Electrode

[0114] A1: Maintenance area

[0115] A2: Ignorance area

[0116] 200: Active material layer

[0117] 300: Whole house

[0118] 310: Metal layer

[0119] 310a: First metal layer

[0120] 310b: Second metal layer

[0121] 311: Metal layer body

[0122] 311a: First metal layer body

[0123] 311b: Second metal layer body

[0124] 312: Connecting protrusion

[0125] 312a: First connecting projection

[0126] 312b: Second connecting projection

[0127] 313: Connecting Bridge

[0128] 320: Middle layer

[0129] 321: Middle layer body

[0130] 322H: Accommodation Home

[0131] 322Ha: 1st receiving groove

[0132] 322Hb: 2nd receiving groove

[0133] 400: Separator

[0134] 500: Electrode Lead

[0135] 510: Lead film

Claims

1. A pair of metal layers; and It includes an intermediate layer located between the above-mentioned pair of metal layers and having a polymer material, The above intermediate layer has an inwardly concave receiving groove, The above pair of metal layers, A metal layer body in contact with the above intermediate layer; and A current collector comprising a connecting projection protruding from the metal layer body to be received in the receiving groove.

2. In Paragraph 1, The above receiving groove is a current collector located adjacent to the end of the above intermediate layer.

3. In Paragraph 1, The above pair of metal layers and the above intermediate layer, A retention region where the active material layer is to be located; and A blank region where the above active material layer is not located is defined, and The above receiving groove is a collector located in the above-mentioned non-receiving area.

4. In Paragraph 3, The above receiving grooves are provided in multiple numbers, and A plurality of the above-mentioned receiving grooves are a current collector located in the above-mentioned retention area.

5. In Paragraph 1, The above receiving groove is a whole house in which no corners are provided at the ends.

6. In Paragraph 1, The above receiving groove is a current collector having a spherical end.

7. In Paragraph 1, The above pair of metal layers is defined as a first metal layer and a second metal layer, and The above receiving groove is, A first receiving groove facing the first metal layer; and A current collector comprising a second receiving groove facing the second metal layer.

8. In Paragraph 7, A collector configured such that the first receiving groove does not come into contact with the second receiving groove.

9. In Paragraph 7, The above first receiving grooves are provided in plurality and arranged, The above-mentioned second receiving grooves are provided in plurality and arranged, A plurality of first receiving grooves and a plurality of second receiving grooves are arranged alternately in a current collector.

10. In Paragraph 7, The above current collector is configured so that its thickness is reduced by rolling, and The connecting projection included in the first metal layer is defined as the first connecting projection, and The connecting projection included in the second metal layer is defined as a second connecting projection, and The first connecting projection and the second connecting projection are positioned closer than the thickness of the current collector that is reduced by rolling so as to meet when the current collector is rolled.

11. In Paragraph 10, A current collector configured such that the first connecting projection and the second connecting projection are connected to each other by ultrasonic welding.

12. In Paragraph 1, The above receiving grooves are provided in multiple numbers, and The above connecting protrusions are provided in multiple numbers to correspond to a plurality of the above receiving grooves, and A welding area in which a plurality of the receiving grooves are located is defined in the above pair of metal layers and the above intermediate layer, and A plurality of the above-mentioned connecting protrusions are arranged to have a larger volume than the intermediate layer in the welding area.

13. In Paragraph 1, The above metal layer is a current collector bonded to the above intermediate layer by deposition.

14. In Paragraph 1, The above metal layer is a current collector comprising aluminum material.

15. In Paragraph 1, The above intermediate layer is a current collector comprising at least one of PET (Polyethylene Terephthalate) or PP (Polypropylene) material.

16. Active material layer; and It includes a current collector to which the above active material layer is bonded, and The entire house mentioned above is, metal layer; and It includes an intermediate layer bonded to the above metal layer and having a polymer material, The above intermediate layer has an inwardly concave receiving groove, The above metal layer is, A metal layer body in contact with the above intermediate layer; and An electrode comprising a connecting projection protruding from the metal layer body to be received in the receiving groove.

17. In Paragraph 16, The above receiving groove is an electrode located adjacent to the end of the above intermediate layer.

18. In Paragraph 16, In the metal layer and the intermediate layer above, A retention region overlapping with the above active material layer; and A non-existent region that does not overlap with the above active material layer is defined, and The above receiving groove is an electrode located in the above-mentioned non-receiving area.

19. In Paragraph 18, The above receiving grooves are provided in multiple numbers, and A plurality of the above-mentioned receiving grooves are electrodes located in the above-mentioned retention area.

20. Electrode; and It includes a battery case in which the above electrode is accommodated, and Active material layer; and It includes a current collector to which the above active material layer is bonded, and The entire house mentioned above is, metal layer; and It includes an intermediate layer bonded to the metal layer and having a density lighter than that of the metal layer, The above intermediate layer has an inwardly concave receiving groove, The above metal layer is, A metal layer body in contact with the above intermediate layer; and A secondary battery comprising a connecting projection protruding from the metal layer body to be received in the receiving groove.

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