Electrode assembly, battery cell comprising same, and electrode lead welding method

Abstract

The present invention relates to an electrode assembly, a battery cell comprising same, and an electrode lead welding method. The electrode assembly according to one embodiment of the present invention may comprise: a plurality of electrodes having electrode tabs; and an electrode lead coupled to the electrode tabs. The plurality of electrode tabs may include a first electrode tab, and a second electrode tab which is coupled to one surface of the electrode lead and is different in appearance from the first electrode tab.

Description

Electrode assembly, battery cell including same, and electrode lead welding method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0149462, dated November 1, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to an electrode assembly, a battery cell including the same, and a method for welding electrode leads.

[0005] In recent years, rising energy prices due to the depletion of fossil fuels and growing concerns about environmental pollution have made the demand for eco-friendly alternative energy sources essential for future living. Research is continuing into various power generation technologies, such as solar, wind, and tidal power. Furthermore, significant interest is being focused on power storage devices, such as batteries, to more efficiently utilize the generated electricity.

[0006] Moreover, with the development of technology and increasing demand for battery-powered electronic mobile devices and battery-powered automobiles, the demand for batteries as an energy source is rapidly increasing, and accordingly, much research is being conducted on batteries that can meet various needs.

[0007] Batteries are attracting significant attention as an energy source for a variety of products, including mobile devices and electric vehicles. Secondary batteries, in particular, are an excellent energy source that can replace the use of existing fossil fuel-powered products. They are also gaining recognition as an eco-friendly energy source, as they produce no byproducts from energy use.

[0008] Meanwhile, secondary batteries are also attracting attention as a power source for electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), which are being proposed as solutions to address air pollution issues caused by conventional gasoline and diesel vehicles that use fossil fuels. Specifically, these secondary batteries are utilized in battery packs containing multiple battery modules.

[0009] Secondary batteries include anodes and cathodes, which are laminated with a separator between them to form an electrode assembly. Each anode and cathode has an electrode tab, and since multiple anodes and multiple cathodes have electrode tabs, a plurality of electrode tabs are formed. These multiple electrode tabs are electrically connected to electrode leads. Conventionally, electrode tabs were made of metal. Recently, electrode tabs have begun to be manufactured from materials other than metal. A representative example is metallized films, which deposit metal on a non-metallic material, specifically a polymer layer.

[0010] Conventional electrode tabs were attached via pre-welding, then welded by driving the leads to one end. However, this method presented problems when applied to metallized films: poor welding, or even when welding was successful, insufficient fusion strength resulted in partial detachment. This resulted in a significant number of defects during the secondary battery assembly process.

[0011] The present invention has been devised to solve the above problems, and a task to be solved by the present invention is to provide an electrode assembly, a battery cell including the same, and an electrode lead welding method, in which when welding is performed by placing electrode leads between electrode tabs, the appearance of some electrode tabs is made different from other electrode tabs so that the position of the electrode leads can be easily identified.

[0012] An electrode assembly according to one embodiment of the present invention includes a plurality of electrodes having electrode tabs; and electrode leads coupled with the electrode tabs, wherein the plurality of electrode tabs may include a first electrode tab; and a second electrode tab coupled with one surface of the electrode lead and having an external difference from the first electrode tab.

[0013] The second electrode tab may be formed to have a different color from the first electrode tab.

[0014] The second electrode tab may include a material having a lower rigidity than the first electrode tab.

[0015] The second electrode tab can be coupled to at least one of both sides of the electrode lead.

[0016] Each of the first electrode tab and the second electrode tab may include a pair of metal layers arranged at the outermost end; and a non-metal layer arranged between the pair of metal layers.

[0017] The above pair of metal layers may be characterized in that they are deposited on both sides of the non-metal layer.

[0018] The non-metallic layer may include a polymer, and the metal layer may include aluminum.

[0019] The above electrode lead can be combined with the electrode tab at the center in the thickness direction of the electrode.

[0020] Based on the above electrode lead, the same number of electrode tabs can be arranged in the upper and lower directions of the electrode lead.

[0021] The above electrode lead and the second electrode tab can be joined by welding.

[0022] The first electrode tab may include a pair of metal layers arranged at the outermost end; and a non-metal layer arranged between the pair of metal layers, and the second electrode tab may be composed of a metal.

[0023] A battery cell according to one embodiment of the present invention may include the electrode assembly; and a battery case in which the electrode assembly is accommodated.

[0024] An electrode lead welding method according to one embodiment of the present invention can weld an electrode tab and an electrode lead.

[0025] The above electrode lead welding method includes a step of placing the electrode lead at a location where the electrode tab is located; and a step of welding the electrode tab and the electrode lead, wherein the electrode tab includes a first electrode tab; and a second electrode tab that is joined to one side of the electrode lead and has an appearance different from the first electrode tab, and in the step of placing the electrode lead, the electrode lead can be placed at a location where the second electrode tab is located.

[0026] According to a preferred embodiment of the present invention, there is an effect in which the point where the electrode lead is placed can be easily identified by making the color of the adjacent electrode tab at the part where the electrode lead is placed different or using a soft material.

[0027] Additionally, the electrode tab adjacent to the electrode lead contains a softer material than the other electrode tabs, which has the effect of achieving the target fusion strength when welding with the electrode lead.

[0028] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0029] Figure 1 is a schematic diagram of a battery cell according to one embodiment of the present invention.

[0030] Figure 2 is an enlarged view of part A of Figure 1.

[0031] Figure 3 is a plan view of the electrode and electrode tab illustrated in Figure 1.

[0032] FIG. 4 is an enlarged view of a welded portion between an electrode tab and an electrode lead of an electrode assembly according to another embodiment of the present invention.

[0033] FIG. 5 is a cross-sectional view showing a cross-section of an electrode tab according to one embodiment of the present invention.

[0034] Figure 6 is a flowchart of an electrode lead welding method according to another embodiment of the present invention.

[0035] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0036] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0037] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0038]

[0039] Electrode assembly and battery cell

[0040] Hereinafter, an electrode assembly (10) and a battery cell (1) including the same according to one embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5.

[0041] FIG. 1 is a schematic diagram of a battery cell according to one embodiment of the present invention, FIG. 2 is an enlarged view of part A of FIG. 1, FIG. 3 is a plan view of an electrode and an electrode tab shown in FIG. 1, FIG. 4 is an enlarged view of a welded portion between an electrode tab and an electrode lead of an electrode assembly according to another embodiment of the present invention, and FIG. 5 is a cross-sectional view showing a cross-section of an electrode tab according to one embodiment of the present invention.

[0042] Referring to FIG. 1, a battery cell (1) according to one embodiment of the present invention may include an electrode assembly (10) and a battery case (20). The electrode assembly (10) may be accommodated in the battery case (20). An electrolyte may be accommodated within the battery case (20). The electrode assembly (10) may be impregnated with the electrolyte. The electrolyte may permeate the electrode assembly (10), thereby enabling movement of ions between electrodes. The battery case (20) may be formed of a pouch-shaped material.

[0043] An electrode assembly (10) according to one embodiment of the present invention may include a plurality of electrodes (11) and electrode leads (13). The electrode assembly (10) may be formed by stacking electrodes (11) and a separator on top of each other.

[0044] A plurality of electrodes (11) may each be provided with electrode tabs (12). The electrodes (11) may be positive or negative. The positive electrode may include a region coated with an active material layer and a positive electrode non-coated region where the active material layer is not coated. The negative electrode may include a region coated with an active material layer and a negative electrode non-coated region where the active material layer is not coated.

[0045] The electrode tab (12) may be plural since it is connected to a plurality of electrodes (11). The electrode tab (12) may be an anode electrode tab or a cathode electrode tab. The anode electrode tab is an electrode tab (12) connected to the anode, and the cathode electrode tab is an electrode tab (12) connected to the cathode. The anode cathode tab and the cathode electrode tab may each be connected to an electrode lead (13).

[0046] The electrode tab (12) may include a first electrode tab (121) and a second electrode tab (122).

[0047] The first electrode tab (121) may be a positive electrode tab or an electrode negative electrode tab. A plurality of first electrode tabs (121) may be formed. A plurality of first electrode tabs (121) may be welded to each other.

[0048] The second electrode tab (122) can be coupled to one side of the electrode lead (13). The second electrode tab (122) can be coupled to at least one of both sides of the electrode lead (13). That is, the second electrode tab (122) can be coupled to the lower surface or the upper surface of the electrode lead (13). Referring to FIG. 2, an electrode assembly according to an embodiment of the present invention may include a single second electrode tab (122). In addition, referring to FIG. 4, an electrode assembly according to an embodiment of the present invention may include a pair of second electrode tabs (122).

[0049] The second electrode tab (122) may have an external difference from the first electrode tab (121).

[0050] For example, the second electrode tab (122) may be formed to have a different color from the first electrode tab (121). Since the second electrode tab (122) is formed to have a different color from the first electrode tab (121), the welding location can be easily determined by placing the electrode lead (13). The color of the second electrode tab (122) may be distinguished from the color of the first electrode tab (121).

[0051] The electrode lead (13) can be welded to the second electrode tab (122). After placing the electrode lead (13) between the second electrode tab (122) and the first electrode tab (121), the electrode lead (13) and the electrode tab (12) can be welded.

[0052] The first electrode tab (121) and the second electrode tab (122) may each include a pair of metal layers (123) and a non-metal layer (124). The first electrode tab (121) and the second electrode tab (122) may be a metallized film in which a metal layer is deposited on a non-metal layer. The metallized film may be formed thinner than the electrode tab composed of metal.

[0053] Metallized films can be classified into deposited films and laminated films depending on the manufacturing process. Deposited films are manufactured by a deposition method, and laminated films are manufactured by applying pressure. Generally, laminated films have a weaker rigidity than deposited films. There is also a difference in appearance. In the present invention, the second electrode tab (122) is formed of a laminated film, and the first electrode tab (121) is formed of a deposited film, so that the portion where the electrode lead (13) is welded can be easily identified, and the second electrode tab (122) welded to the electrode lead (13) is formed of a laminated film with weak rigidity, so that the target fusion strength can be achieved.

[0054] The metal layer (123) is provided in pairs and can be arranged at the outermost layer. The metal layer (123) can include aluminum. The metal layer (123) is provided so that the electrode tabs (12) can be electrically connected to each other.

[0055] A non-metallic layer (124) may be placed between a pair of metal layers (123). Metal layers (123) may be deposited on both sides of the non-metallic layer (124). Since the metal layer (123) is deposited on the non-metallic layer (124), the non-metallic layer (124) may be formed to be thinner than when composed solely of metal. The non-metallic layer (124) may include a polymer.

[0056] As another example, the second electrode tab (122) may include a material having a lower rigidity than the first electrode tab (121). If the second electrode tab (122) is made of a soft material, when welding the electrode lead (13) and the electrode tab (12), welding defects between the second electrode tab (122) and the electrode lead (13) can be reduced. Since it is a soft material, better fusion can be achieved during welding.

[0057] The second electrode tab (122) may be different in appearance from the first electrode tab (121), wherein the first electrode tab (121) may include a pair of metal layers (123) and non-metal layers (124) as described above. The second electrode tab (122) may be a laminated film.

[0058] The electrode lead (13) can be connected to the electrode tab (12) at the center of the thickness direction of the electrode (11). The electrode lead (13) can be electrically connected to the electrode tab (12). A lead film can be connected to the electrode lead (13). The lead film can be placed between the electrode lead (13) and the battery case (20).

[0059] The electrode lead (13) may be positioned adjacent to the second electrode tab (122). As illustrated in FIG. 2, the electrode lead (13) may be positioned and welded on the upper portion of the second electrode tab (122). That is, when determining the position for welding the electrode lead (13), there is an effect in which the second electrode tab (122) can be easily identified. However, the present invention is not limited thereto, and the second electrode tab (122) may be positioned on the upper portion of the electrode lead (13) as illustrated in FIG. 4. In this case, the electrode lead (13) may be positioned and welded below the second electrode tab (122).

[0060] In order to weld the electrode lead (13), the same number of electrode tabs (12) must be placed above and below the position where the electrode lead (13) is placed. If not otherwise indicated, the task of counting the number of electrode tabs (12) was necessary. However, as described above, since the second electrode tab (122) is formed differently in appearance from the first electrode tab (121), the position of the second electrode tab (122) can be quickly identified, and since the position where the electrode lead (13) should be placed can be easily known, there is an effect of being able to omit the process of counting the number of electrode tabs (12).

[0061] An equal number of electrode tabs (12) can be arranged in the upper and lower directions of the electrode lead (13) based on the electrode lead (13). The electrode lead (13) and the second electrode tab (122) can be welded and joined. The electrode lead (13) can also be welded and joined to the first electrode tab (121).

[0062]

[0063] Electrode lead welding method

[0064] Hereinafter, an electrode lead welding method according to an embodiment of the present invention will be described in detail with reference to FIGS. 2, 4, and 6.

[0065] FIG. 2 is a schematic diagram illustrating the electrode assembly illustrated in FIG. 1, FIG. 4 is a schematic diagram illustrating an electrode assembly according to another embodiment of the present invention, and FIG. 6 is a flowchart of an electrode lead welding method according to another embodiment of the present invention.

[0066] Hereinafter, an electrode lead welding method using the electrode assembly (10) and battery cell (1) described above will be described as another embodiment of the present invention.

[0067] Referring to FIG. 6, an electrode tab (12) and an electrode lead (13) can be welded through an electrode lead welding method according to an embodiment of the present invention. The electrode lead welding method according to an embodiment of the present invention may include a step (S1) of placing an electrode lead and a step (S2) of welding an electrode tab (12) and an electrode lead (13).

[0068] In the step (S1) of placing the electrode lead, the electrode lead (13) can be placed where the second electrode tab (122) is located. More specifically, the electrode lead (13) can be placed so as to be in contact with the second electrode tab (122). Since the electrode lead (13) must be placed and welded at the center of the thickness direction of the electrode (11), the electrode lead (13) must be placed where the second electrode tab (122) is located. As described above, since the second electrode tab (122) is different in appearance from the first electrode tab (121), there is an effect of being able to easily determine where the electrode lead (13) is placed.

[0069] In the step of welding the electrode lead (S2), the electrode lead (13) and the electrode tab (12) can be welded together. At this time, multiple electrode tabs (12) can be welded at once.

[0070] In the step (S2) of welding the electrode lead, the number of electrode tabs (12) arranged on the lower side of the electrode lead (13) may be greater than the number of electrode tabs (12) arranged on the upper side of the electrode lead (13). When the number of electrode tabs (12) arranged on the upper side of the electrode lead (13) is greater than the number of electrode tabs (12) arranged on the lower side of the electrode lead (13), when welding the electrode lead (13) and the second electrode tab (122), the target fusion strength may not be achieved or welding may be impossible.

[0071] In the conventional electrode lead welding method, the electrode lead is welded after a pre-welding step of welding the electrode tab separately, but the method of the present invention has the feature of being able to weld the electrode lead (13) and the electrode tab (12) at once without a pre-welding step.

[0072] However, when welding is performed by placing the electrode lead (13) on one side of the electrode tab (12) as in the past, there was a problem that welding was impossible. In the present invention, the electrode lead (13) is placed between the electrode tabs (12) and welded, and in order to facilitate welding, the electrode lead (13) is placed in the center of the thickness direction of the electrode (11) and welded. Therefore, there is an effect that the electrode lead (13) can be appropriately placed and welded by providing the second electrode tab (122).

[0073]

[0074] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope equivalent to the technical idea of ​​the present invention and the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0075] [Explanation of symbols]

[0076] 1: Battery cell

[0077] 10: Electrode assembly

[0078] 11: Electrode

[0079] 12: Electrode tab

[0080] 121: First electrode tab

[0081] 122: Second electrode tab

[0082] 123: Metal layer

[0083] 124: Non-metallic layer

[0084] 13: Electrode leads

[0085] 20: Battery case

[0086] S1: Deployment phase

[0087] S2: Welding stage

Claims

1. A plurality of electrodes having electrode tabs; and comprising an electrode lead coupled to the electrode tab; A plurality of the above electrode tabs, first electrode tab; and An electrode assembly comprising a second electrode tab coupled to one side of the electrode lead and having an external difference from the first electrode tab.

2. In paragraph 1, An electrode assembly in which the second electrode tab is formed to have a different color from the first electrode tab.

3. In paragraph 1, An electrode assembly wherein the second electrode tab comprises a material having a lower rigidity than the first electrode tab.

4. In paragraph 1, An electrode assembly wherein the second electrode tab is coupled to at least one of both sides of the electrode lead.

5. In paragraph 1, Each of the first electrode tab and the second electrode tab, A pair of metal layers arranged at the outermost layer; and An electrode assembly comprising a non-metallic layer disposed between the pair of metal layers.

6. In paragraph 5, An electrode assembly characterized in that the pair of metal layers are deposited on both sides of the non-metal layer.

7. In paragraph 5, The above non-metallic layer comprises a polymer, The above metal layer is an electrode assembly comprising aluminum.

8. In paragraph 1, The electrode lead is an electrode assembly that is joined to the electrode tab at the center in the thickness direction of the electrode.

9. In paragraph 1, An electrode assembly in which the same number of electrode tabs are arranged in the upper and lower directions of the electrode lead based on the electrode lead.

10. In paragraph 1, An electrode assembly in which the electrode lead and the second electrode tab are welded together.

11. In paragraph 1, The above first electrode tab, A pair of metal layers arranged at the outermost layer; and comprising a non-metallic layer disposed between the pair of metal layers; The above second electrode tab is an electrode assembly made of metal.

12. The electrode assembly described in paragraph 1; and A battery cell comprising a battery case in which the electrode assembly is accommodated.

13. In an electrode lead welding method for welding an electrode tab and an electrode lead, a step of placing the electrode lead where the electrode tab is located; and comprising a step of welding the electrode tab and the electrode lead, The above electrode tab is first electrode tab; and A second electrode tab is coupled to one side of the electrode lead and has an appearance different from the first electrode tab, In the step of placing the above electrode leads, An electrode lead welding method in which the electrode lead is positioned where the second electrode tab is located.

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