Electrode tab, electrode assembly, and secondary battery including the same

Abstract

The present invention relates to an electrode tab, an electrode assembly, and a secondary battery including the same, and more particularly to an electrode tab, an electrode assembly, and a secondary battery including the same, in which the thickness of the electrode tab is adjusted as necessary so that the durability of the electrode tab against heat or vibration can be adjusted in various ways, thereby enabling improvement in the performance and safety of the battery. The electrode assembly according to the present invention includes a positive electrode plate having a positive active material coated on a current collector, a negative electrode plate having a negative active material coated on a current collector, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrode tab connected to the positive electrode plate or the negative electrode plate and formed by stacking a plurality of metal plates.

Description

Technical Field

[0001] Cross-reference to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2021-0021387, filed on February 17, 2021, which is incorporated herein by reference in its entirety. Technical Field

[0004] The present invention relates to electrode contacts, electrode assemblies, and secondary batteries including the electrode assemblies, and more specifically, to electrode contacts, electrode assemblies, and secondary batteries including the electrode assemblies, wherein the thickness of the electrode contacts is adjusted to differently adjust their durability against heat or vibration, thereby improving the performance and safety of the battery. Background Technology

[0005] A secondary battery is a rechargeable and dischargeable battery, distinct from a non-rechargeable primary battery. Secondary batteries are widely used not only in small electronic devices such as mobile phones and laptops, but also in large products requiring high output, such as electric vehicles, power storage devices for storing surplus or renewable energy, and power storage devices for backup.

[0006] Such secondary batteries are classified as: cylindrical batteries or prismatic batteries in which the electrode assembly is built into a cylindrical or prismatic metal can, and pouch batteries in which the electrode assembly is built into a pouch box provided as an aluminum laminate.

[0007] Additionally, secondary batteries are rechargeable and dischargeable power generators, and are classified according to electrode assemblies having a positive / separator / negative electrode structure. Representatively, exemplary examples of electrode assemblies may include: jelly roll type (wound type) electrode assemblies, wherein elongated sheet-shaped positive and negative electrodes are wound together, with a separator between the positive and negative electrodes; stacked type (stacked type) electrode assemblies, wherein multiple positive and negative electrodes cut into units are sequentially stacked, with a separator between the positive and negative electrodes, each of the units having a predetermined size; stacked folded type electrode assemblies, wherein stacked dual-cell units or full-cell units are wound together, with separators between the dual-cell units or full-cell units. Among these, jelly roll type electrode assemblies are widely used as electrode assemblies mounted in cylindrical battery cases due to their ease of manufacture and high energy density per unit weight.

[0008] In a cylindrical secondary battery, a jelly roll-type electrode assembly is housed in a battery case made of a metal can material. The battery case has an open upper side, and a cover assembly covers the upper side of the opening of the battery case. The jelly roll-type electrode assembly housed in the battery case is provided with a positive electrode tab and a negative electrode tab (hereinafter referred to as "electrode tabs"), which are attached to the positive and negative electrodes and protrude upwards and downwards from the jelly roll-type battery assembly, respectively.

[0009] On the other hand, when vibration occurs within a cylindrical secondary battery, the electrode assembly vibrates within the internal space of the battery case while being housed there, and in this case, the electrode contacts can be broken by the vibration. This problem occurs more frequently when the cylindrical secondary battery is used as a power source for devices frequently exposed to strong vibrations, such as power tools, or when exposed to unwanted external impacts, such as drops. Furthermore, during high-rate discharge, a large current is applied, and therefore, high heat is generated in the electrode contacts, causing them to break. Therefore, it is impossible to maintain battery performance.

[0010] Therefore, there is a need to develop an electrode tab, an electrode assembly, and a secondary battery including the electrode assembly, wherein the electrode tab can ensure battery safety and maintain necessary performance by appropriately adjusting the durability of the electrode tab. Summary of the Invention

[0011] Technical issues

[0012] The present invention is designed to solve the above problems, and the object of the present invention is to provide an electrode tab, an electrode assembly, and a secondary battery including the electrode assembly, wherein the thickness of the electrode tab is adjusted to adjust the durability of the electrode tab to heat and vibration, thereby improving the performance and safety of the battery.

[0013] Technical solutions

[0014] The electrode assembly according to the invention includes: a positive electrode plate coated with a positive active material on a current collector; a negative electrode plate coated with a negative active material on a current collector; a separator between the positive electrode plate and the negative electrode plate; and an electrode contact connected to the positive electrode plate and the negative electrode plate and formed by stacking a plurality of metal plates.

[0015] Electrode contacts can be formed by stacking multiple metal plates of the same length.

[0016] Electrode tabs can be formed by stacking multiple metal plates of different lengths, wherein one side of the electrode tab can have a thickness greater than the thickness of the other side of the electrode tab.

[0017] The plurality of metal plates may include: a first metal plate having a certain length; and a second metal plate stacked on the first metal plate and having a length less than that of the first metal plate.

[0018] The second metal plate may have a length less than half the length of the first metal plate.

[0019] The plurality of metal plates may also include a third metal plate, which is stacked on the second metal plate and has a length less than or equal to the length of the second metal plate.

[0020] In an electrode tab, multiple metal plates of different lengths can be arranged such that the ends of the multiple metal plates match each other on one side of the electrode tab.

[0021] The side of the electrode contact with a relatively thick thickness can be connected to either the positive or negative electrode plate.

[0022] The other side of the electrode tab, which has a relatively thin thickness, can be connected to either the positive or negative electrode plate.

[0023] The electrode contacts according to the present invention are connected to the positive or negative electrode plate and are formed by stacking multiple metal plates.

[0024] Multiple metal plates can have the same length.

[0025] Multiple metal plates can have different lengths, and one side of the multiple metal plates can have a thickness greater than the thickness of the other side of the metal plate.

[0026] The secondary battery according to the present invention includes: an electrode assembly comprising a positive electrode plate coated with a positive active material on a current collector, a negative electrode plate coated with a negative active material on a current collector, a separator between the positive electrode plate and the negative electrode plate, and electrode contacts connected to the positive electrode plate and the negative electrode plate and formed by stacking a plurality of metal plates; a battery case configured to house the electrode assembly therein; and a cover assembly coupled to the upper part of the battery case.

[0027] Beneficial effects

[0028] The electrode assembly according to the present invention may include: a positive electrode plate coated with a positive electrode active material on a current collector, a negative electrode plate coated with a negative electrode active material on a current collector, a separator between the positive electrode plate and the negative electrode plate, and an electrode tab connected to the positive electrode plate or the negative electrode plate and formed by stacking multiple metal plates. Therefore, the thickness of the electrode tab can be adjusted to adjust the durability of the electrode tab to heat or vibration, thereby improving the performance and safety of the battery. Attached Figure Description

[0029] Figure 1This is a perspective view showing the state in which an electrode patch formed by stacking multiple metal plates of the same length in an electrode assembly according to Embodiment 1 of the present invention is connected to a positive or negative electrode plate.

[0030] Figure 2 This is a perspective view showing the state in which one side of the electrode tab with a relatively thick thickness is connected to the positive or negative electrode plate in the electrode assembly according to Embodiment 1 of the present invention.

[0031] Figure 3 This is a perspective view showing the state in which the other side of the electrode tab, having a relatively thin thickness, is connected to the positive or negative electrode plate in the electrode assembly according to Embodiment 1 of the present invention.

[0032] Figure 4 This is a side view showing the shape of the electrode contact according to Embodiment 2 of the present invention, wherein, Figure 4 (a) is a side view showing an electrode patch formed by stacking multiple metal plates of the same length, and Figure 4 (b) is a side view showing an electrode patch formed by stacking multiple metal plates of different lengths.

[0033] Figure 5 This is an exploded perspective view of a secondary battery according to Embodiment 3 of the present invention. Detailed Implementation

[0034] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings, enabling those skilled in the art to readily implement the invention. However, the invention may be implemented in several different forms and is not limited to or construed as described below.

[0035] To clearly explain the invention, detailed descriptions of irrelevant parts or related known technologies that may unnecessarily obscure the spirit of the invention have been omitted, and reference numerals have been added to components in each figure. In this case, the same or similar reference numerals are assigned to the same or similar elements throughout the specification.

[0036] Furthermore, the terms or words used in this specification and claims should not be construed as having a general meaning or a dictionary-based meaning, but should be interpreted as having a meaning and concept that is within the scope of the invention, based on the principle that the inventor can appropriately define the concepts of the terms to best describe and explain his or her invention.

[0037] Implementation Method 1

[0038] Figure 1This is a perspective view showing the state in which an electrode patch formed by stacking multiple metal plates of the same length in an electrode assembly according to Embodiment 1 of the present invention is connected to a positive or negative electrode plate. Figure 2 This is a perspective view showing the state in which one side of the electrode tab with a relatively thick thickness is connected to the positive or negative electrode plate in the electrode assembly according to Embodiment 1 of the present invention. Figure 3 This is a perspective view showing the state in which the other side of the electrode tab, having a relatively thin thickness, is connected to the positive or negative electrode plate in the electrode assembly according to Embodiment 1 of the present invention.

[0039] Reference Figures 1 to 3 According to Embodiment 1 of the present invention, the electrode assembly 10 includes a positive electrode plate 100, a negative electrode plate 200, a separator 300 and an electrode contact 400.

[0040] First, refer to Figure 1 The positive electrode plate 100 may be coated with a positive electrode active material on the positive electrode current collector, and the positive electrode current collector may be coated with a positive electrode active material on both surfaces of the positive electrode current collector, which is made of a metal sheet with excellent conductivity, such as aluminum (Al) foil. That is, the positive electrode active material may include: lithium cobalt oxide with high operating voltage and excellent capacity characteristics; lithium nickel oxide with high reversible capacity and easy realization of large-capacity batteries; lithium nickel cobalt oxide in which cobalt replaces a portion of nickel; lithium nickel cobalt metal oxide in which manganese, cobalt or aluminum replaces a portion of nickel; low-cost lithium manganese oxide with excellent thermal stability; lithium iron phosphate with excellent stability, etc.

[0041] The negative electrode plate 200 may be coated with a negative electrode active material on the negative electrode current collector, and the negative electrode current collector may include a negative electrode current collector made of a thin metal plate with excellent conductivity, such as copper (Cu) or nickel (Ni) foil, and a layer of negative electrode active material applied to both surfaces of the negative electrode current collector. The negative electrode active material may be, for example, a carbon material such as crystalline carbon, amorphous carbon, carbon composites and carbon fibers, lithium metal or lithium alloy.

[0042] The area of ​​the current collector where no active material layer is formed can be an uncoated portion (not shown), and refers to the area where the positive or negative current collector is exposed. The electrode tab 400, described later, can be connected to the uncoated portion and can be extended to a predetermined length relative to the upper or lower side of the electrode assembly 10. The electrode tab 400 can be divided into a positive tab connected to the uncoated portion of the positive current collector and a negative tab connected to the uncoated portion of the negative current collector, the positive tab and the negative tab being extended to a predetermined distance from the upper and lower sides of the electrode assembly 10, respectively.

[0043] In electrode assembly 10, the positive electrode 100 and the negative electrode 200 must be in close contact with each other to minimize internal resistance. However, when the positive electrode 100 and the negative electrode 200 are in direct contact, an internal short circuit occurs, rendering the battery ineffective. Therefore, electrode assembly 10 includes a separator 300 between the positive electrode 100 and the negative electrode 200 to prevent short circuits. The separator 300 can be disposed between the positive and negative electrodes with a certain mechanical strength and is made of a porous material to facilitate the movement of ions between the electrodes, for example, made of any base material selected from the group consisting of polyethylene (PE), polystyrene (PS), and copolymers of polyethylene (PE) and polypropylene (PP).

[0044] According to Embodiment 1 of the present invention, the electrode contact 400 is connected to the positive electrode plate 100 or the negative electrode plate 200, and is formed by stacking a plurality of metal plates 400a, 400b, and 400c. Here, each of the metal plates 400a, 400b, and 400c is made of a conductive metallic material. For example, the positive electrode contact may be made of aluminum (Al) or an aluminum alloy, and the negative electrode contact may be made of nickel (Ni), copper (Cu), or a nickel alloy. Alternatively, each of the positive and negative electrode contacts may be made of various other materials. The plurality of metal plates 400a, 400b, and 400c may be stacked to bond to each other by welding or conductive adhesive, and may also be stacked together with metal plates made of the same or different materials.

[0045] As described above, in Embodiment 1 of the present invention, the thickness of the electrode tab 400 can be adjusted in various ways to enhance the durability of the electrode tab 400 against heat and vibration, and to prevent the electrode tab 400 from breaking, thereby improving battery performance. That is, multiple metal plates manufactured and used according to existing technology and having specific standards can be stacked to form the electrode tab 400, allowing the thickness of the electrode tab 400 to be easily adjusted as needed. For example, when multiple thin metal plates can be stacked to manufacture an electrode with an overall thickness, the resistance of the electrode tab 400 can be reduced, and the heat generated by the electrode tab 400 can be reduced. Therefore, even at high current rates, the resulting electrode tab 400 can maintain battery performance and can thus be applied to high-output models. Furthermore, the thickness of the electrode tab 400 can be easily adjusted by simply adding means for performing stacking or bonding processes without changing or replacing existing equipment used to manufacture the metal plates used in the electrode tab 400, thereby ensuring the economic efficiency and productivity of the manufacturing process.

[0046] like Figure 1As shown, the electrode contact 400 according to Embodiment 1 of the present invention can be formed by stacking multiple metal plates 400a, 400b, and 400c having the same length. In this case, the electrode contact 400 has enhanced vibration resistance compared to a single-layer electrode contact with the same thickness, and therefore the battery performance can be maintained even when the electrode contact 400 is used in an environment exposed to vibration. In addition, when multiple thin metal plates 400a, 400b, and 400c are stacked to form an electrode contact 400 with a thick thickness, the heat generated can be reduced due to the reduced resistance. Therefore, there is a significant advantage in manufacturability compared to stacking methods that include electrode contacts 400 with metal plates of different lengths (described later).

[0047] As mentioned above, increasing the thickness of the electrode contacts 400 can enhance heat resistance and vibration resistance. However, in some cases, when vibrations and heat of a certain or greater intensity are generated, it is necessary to ensure battery safety by cutting off the electrode contacts 400. That is, it is necessary to appropriately modify the durability of the electrode contacts 400 according to the battery type, structure, application, and capacity.

[0048] Therefore, the electrode contact 400 according to Embodiment 1 of the present invention can be as follows: Figure 2 and Figure 3 The electrode contact 400 is formed by stacking multiple metal plates 400a, 400b, and 400c of different lengths, and the thickness of one side of the electrode contact 400 can be made thicker than the thickness of the other side. That is, since the metal plates with relatively short lengths are stacked on one side of the upper part of the metal plates with relatively long lengths, one side of the electrode contact 400 can have a relatively thick thickness to enhance heat resistance and vibration resistance. Conversely, the other side of the electrode contact 400 can have a relatively thin thickness to reduce durability, making the electrode contact 400 easier to cut, and thus ensuring battery safety.

[0049] Specifically, according to Embodiment 1 of the present invention, the metal plates stacked on the electrode contacts 400 may include a first metal plate 400a and a second metal plate 400b. The first metal plate 400a may be formed to have a certain length, and the second metal plate 400b may be stacked on top of the first metal plate 400a and formed to have a length less than that of the first metal plate 400a. As described above, since the first metal plate 400a and the second metal plate 400b have different lengths, the area on which the second metal plate 400b is disposed can have enhanced resistance to vibration and heat, but the area on which the second metal plate 400b is not disposed can have weakened resistance to vibration and heat, and therefore disconnection under appropriate vibration and heat generation conditions can ensure battery safety.

[0050] Furthermore, the second metal plate 400b can be formed to be half the length of the first metal plate 400a. Therefore, if necessary, the effect of weakening the durability of the other side of the electrode contact 400 can be maximized.

[0051] The metal plate may also include a third metal plate 400c, which is stacked on the second metal plate 400b and has a length less than or equal to that of the second metal plate 400b. Therefore, one side of the electrode tab 400 can have a thicker thickness to maximize the effect of enhancing the durability of that side of the electrode tab 400.

[0052] Multiple metal plates 400a, 400b, and 400c of different lengths can be configured such that the ends of the metal plates 400a, 400b, and 400c mate with each other on one side of the electrode tab 400. For example, when the electrode tab 400 includes a first metal plate 400a, a second metal plate 400b, and a third metal plate 400c, the ends of the first metal plate 400a, the second metal plate 400b, and the third metal plate 400c are configured to mate with each other on one side of the electrode tab 400, and a stepped portion can be formed on the other side of the electrode tab 400. As described above, when the ends of the multiple metal plates 400a, 400b, and 400c are configured to mate with each other on one side of the electrode tab 400, the structure of the electrode tab 400 can be stably maintained to prevent the multiple metal plates 400a, 400b, and 400c that are joined together from separating from each other, thereby minimizing the deformation of the stacked electrode tab 400.

[0053] Reference Figure 2 The relatively thick side of the electrode contact 400 can be connected to the positive electrode plate 100 or the negative electrode plate 200. In this case, since the relatively thin side of the electrode contact 400 is coupled to the cover assembly 30, the electrode contact 400 can be easily disconnected by the generated heat when vibration or high-rate current is applied, thus ensuring the safety of the battery.

[0054] On the other hand, such as Figure 3 As shown, the other side of the electrode contact 400, which has a relatively thin thickness, can be connected to the positive electrode plate 100 or the negative electrode plate 200. In this case, since the side of the electrode contact 400 with a relatively thick thickness is attached to and connected to the cover assembly 30 and the battery case 20, the heat resistance or vibration resistance can be enhanced to prevent the electrode contact 400 from disconnecting from the cover assembly 30 or the battery case 20 due to vibration or heat of the battery case 20.

[0055] Implementation Method 2

[0056] Figure 4This is a side view showing the shape of the electrode contact according to Embodiment 2 of the present invention, wherein, Figure 4 (a) is a side view showing an electrode patch formed by stacking multiple metal plates of the same length, and Figure 4 (b) is a side view showing an electrode patch formed by stacking multiple metal plates of different lengths.

[0057] The difference between Embodiment 2 and Embodiment 1 is that Embodiment 2 is used for electrode contacts 400 in the electrode assembly according to Embodiment 1.

[0058] Content that overlaps with Implementation 1 will be omitted as much as possible, and Implementation 2 will be described by focusing on the differences. That is, obviously, if necessary, content not described in Implementation 2 can be regarded as content of Implementation 1.

[0059] Reference Figure 4 According to Embodiment 2 of the present invention, the electrode tab 400 is connected to the positive or negative electrode plate and is formed by stacking multiple metal plates 400a, 400b and 400c. Therefore, the thickness of the electrode tab 400 can be adjusted as needed to adjust the durability of the electrode tab 400 to heat or vibration, thereby improving the performance and safety of the battery.

[0060] In the electrode tab 400 according to Embodiment 2 of the present invention, multiple metal plates 400a, 400b, and 400c may have the same length. In this case, compared with a single-layer electrode tab having the same thickness, the electrode tab 400's resistance to vibration can be enhanced, and therefore the battery performance can be maintained even when used in an environment exposed to vibration. Furthermore, when the electrode tab 400 is formed to be thicker, compared with a stacking method including electrode tabs 400 comprising metal plates of different lengths, the amount of heat to be generated can be reduced due to the decrease in resistance, thereby improving manufacturability.

[0061] In the electrode tab 400 according to Embodiment 2 of the present invention, the plurality of metal plates 400a, 400b, and 400c may have different lengths, and therefore, the thickness of the electrode tab 400 on one side may be greater than the thickness of the electrode tab 400 on the other side. That is, since the metal plates with relatively shorter lengths are stacked on one side of the upper portion of the metal plates with relatively longer lengths, one side of the electrode tab 400 may have a relatively thicker thickness to enhance heat resistance and vibration resistance. Conversely, the other side of the electrode tab 400 may have a relatively thinner thickness to reduce durability, thereby ensuring battery safety.

[0062] Implementation Method 3

[0063] Figure 5 This is an exploded perspective view of a secondary battery according to Embodiment 3 of the present invention.

[0064] The difference between Embodiment 3 and Embodiment 1 is that Embodiment 3 is a secondary battery 1 that includes the electrode assembly 10 according to Embodiment 1.

[0065] Content that overlaps with Implementation 1 will be omitted as much as possible, and Implementation 3 will be described by focusing on the differences. That is, obviously, if necessary, content not described in Implementation 3 can be regarded as content of Implementation 1.

[0066] Reference Figure 5 According to Embodiment 3 of the present invention, the secondary battery 1 includes an electrode assembly 10, a battery box 20, and a cover assembly 30.

[0067] The electrode assembly 10 may include a positive electrode plate coated with a positive active material on a current collector, a negative electrode plate coated with a negative active material on a current collector, a separator between the positive and negative electrode plates, and an electrode contact 400 connected to the positive and negative electrode plates and formed by stacking multiple metal plates, and which can be inserted into the wound jelly roll battery case 20 described later. The configuration associated with the positive electrode plate, negative electrode plate, separator, and electrode contact can be understood as being the same as the configuration described in Embodiment 1.

[0068] The battery case 20 can house the electrode assembly 10 and can be made of stainless steel, aluminum (Al), etc., but is not limited to these. The battery case 20 can be made of a material that houses the electrode assembly 10 and the electrolyte, has low reactivity, and can protect it from external impacts.

[0069] The cover assembly 30 may include a circuit board and an insulating gasket, and may be coupled to the upper part of the battery box 20 to seal the interior of the battery box 20.

[0070] Although embodiments of the invention have been described with reference to specific examples, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention as defined in the appended claims.

[0071] [Explanation of reference numerals in the attached figures]

[0072] 1: Secondary battery

[0073] 10: Electrode assembly

[0074] 100: Positive plate

[0075] 200: Negative electrode plate

[0076] 300: Separator

[0077] 400: Electrode contacts

[0078] 400a: First metal plate

[0079] 400b: Second metal plate

[0080] 400c: Third metal plate

[0081] 20: Battery Box

[0082] 30: Cover component

Claims

1. An electrode assembly, comprising: A positive electrode plate, wherein the positive electrode plate is coated with a positive electrode active material on a current collector; A negative electrode plate, wherein the negative electrode plate is coated with a negative electrode active material on the current collector; A separator, wherein the separator is located between the positive electrode plate and the negative electrode plate; as well as Electrode contacts, which are connected to the positive electrode plate and the negative electrode plate and formed by stacking multiple metal plates, are provided. The plurality of metal plates have different lengths, and Wherein, one side of the electrode contact has a greater thickness than the other side of the electrode contact. The electrode tab with a relatively thick side is connected to the positive electrode plate or the negative electrode plate.

2. The electrode assembly according to claim 1, wherein, The plurality of metal plates include: A first metal plate, the first metal plate having a certain length; and A second metal plate is stacked on top of the first metal plate and has a length less than that of the first metal plate.

3. The electrode assembly according to claim 2, wherein, The second metal plate has a length that is less than half the length of the first metal plate.

4. The electrode assembly according to claim 2, wherein, The plurality of metal plates also includes a third metal plate, which is stacked on the second metal plate and has a length less than or equal to the length of the second metal plate.

5. The electrode assembly according to claim 1, wherein, In the electrode tab, the plurality of metal plates having different lengths are arranged such that the ends of the plurality of metal plates match each other on one side of the electrode tab.

6. An electrode contact, said electrode contact being connected to a positive electrode plate or a negative electrode plate and formed by stacking a plurality of metal plates having different lengths. in, One side of the plurality of metal plates has a thickness greater than the thickness of the other side of the plurality of metal plates, and The electrode tab has a relatively thick side configured to be connected to the positive electrode plate or the negative electrode plate.

7. A secondary battery, comprising: The electrode assembly according to claim 1; A battery compartment is configured to house the electrode assembly therein; as well as The cover assembly is coupled to the upper part of the battery box.

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