Secondary battery

Abstract

This disclosure relates to a secondary battery capable of facilitating welding to external devices. As an example, a secondary battery is disclosed, comprising: a cylindrical housing; an electrode assembly housed within the cylindrical housing; and a cover assembly sealing the cylindrical housing and including a top cover electrically connected to the positive terminal of the electrode assembly, a terminal plate coupled to the upper portion of the top cover and electrically connected to the negative terminal of the electrode assembly, and a first insulating gasket inserted between the top cover and the terminal plate.

Description

[0001] This application claims priority and benefit to Korean Patent Application No. 10-2022-0012600, filed on January 27, 2022, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to a secondary battery. Background Technology

[0003] Lithium-ion secondary batteries are used as power sources for hybrid or electric vehicles and portable electronic devices due to their high operating voltage and high energy density per unit weight, for example.

[0004] Secondary batteries can be classified according to their shape as cylindrical secondary batteries, prismatic secondary batteries, or pouch secondary batteries. For example, a cylindrical secondary battery typically includes a cylindrical housing, cylindrical electrode assemblies attached to the housing, an electrolyte (optional) injected into the housing to enable the movement of lithium ions, and a cover assembly attached to one side of the housing to prevent electrolyte leakage and to prevent the electrode assemblies from separating.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the background art of the invention, and therefore may contain information that does not constitute prior art. Summary of the Invention

[0006] This disclosure provides a secondary battery that facilitates welding to external devices.

[0007] The secondary battery according to this disclosure may include: a cylindrical housing; an electrode assembly housed in the cylindrical housing; and a cover assembly that seals the cylindrical housing and includes a top cover electrically connected to the positive electrode of the electrode assembly, a terminal plate coupled to the upper part of the top cover and electrically connected to the negative electrode of the electrode assembly, and a first insulating gasket inserted between the top cover and the terminal plate.

[0008] The terminal block can be electrically connected to the cylindrical housing.

[0009] The cylindrical housing may include an inwardly recessed rolled edge at the lower part of the cover assembly and an inwardly bent crimping portion at the upper part of the cover assembly, and the crimping portion covers a portion of the terminal block.

[0010] The terminal block can be located above the edge of the top cover, and the center portion protruding upward from the top cover can be exposed.

[0011] The area of ​​the terminal block can correspond to the area of ​​the edge of the top cover.

[0012] The first insulating washer may be located between the edge of the top cover and the terminal block, and the area of ​​the first insulating washer may be larger than the area of ​​the terminal block.

[0013] The first insulating washer may include an extension that extends upward and covers the side surface of the terminal block.

[0014] The secondary battery may also include a second insulating gasket inserted between the top cover and the cylindrical housing.

[0015] The secondary battery may also include: a vent plate, installed under the upper cover and having a notch; a lower cover, installed under the vent plate and having multiple through holes; and an insulator, inserted between the vent plate and the lower cover.

[0016] The cylindrical housing may include a notch on the bottom surface. Attached Figure Description

[0017] Figure 1 This is a perspective view showing a secondary battery according to an embodiment of the present disclosure.

[0018] Figure 2 This is a cross-sectional view showing a secondary battery according to an embodiment of the present disclosure.

[0019] Figure 3A and Figure 3B yes Figure 2 An enlarged sectional view of part A.

[0020] Figure 4 This is a cross-sectional view showing a secondary battery according to another embodiment of the present disclosure. Detailed Implementation

[0021] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] Examples of the invention are provided to explain it more fully to those skilled in the art, and the following examples can be modified in various other forms. However, the invention can be embodied in many different forms and should not be construed as limited to the examples (or exemplary) embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will convey aspects and features of the invention to those skilled in the art.

[0023] Additionally, for the sake of brevity and clarity, the dimensions or thicknesses of various components are exaggerated in the accompanying drawings. The same reference numerals always refer to the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, it will be understood that when element A is referred to as being "connected to" element B, element A may be directly connected to element B, or an intermediary element C may exist between element A and element B, such that element A and element B are indirectly connected to each other.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising or including” and / or variations thereof are used in this specification, it indicates the presence of the stated features, quantities, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, quantities, steps, operations, elements, components, and / or groups thereof.

[0025] It will be understood that although the terms first, second, etc., may be used herein to describe various components, elements, regions, layers, and / or portions, these components, elements, regions, layers, and / or portions should not be limited by these terms. These terms are used only to distinguish one component, element, region, layer, and / or portion from another component, element, region, layer, and / or portion. Thus, for example, without departing from the teachings of the invention, the first component, first element, first region, first layer, and / or first portion discussed below may be referred to as a second component, second element, second region, second layer, and / or second portion.

[0026] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” and “above” may be used herein to describe the relationship between one element or feature shown in the figures and another element(s). It will be understood that, in addition to the orientation depicted in the figures, the spatial relative terms are also intended to cover different orientations of the device during use or operation. For example, if an element or feature in the figures is flipped, an element described as “below” or “under” other elements or features would subsequently be positioned “above” or “above” said other elements or features. Thus, the exemplary term “below” can encompass both above and below orientations.

[0027] Figure 1 This is a perspective view showing a secondary battery according to an embodiment of the present disclosure. Figure 2 This is a cross-sectional view showing a secondary battery according to an embodiment of the present disclosure. Figure 3A and Figure 3B yes Figure 2 An enlarged sectional view of part A.

[0028] Reference Figures 1 to 3B The secondary battery 100 according to embodiments of the present disclosure may include a cylindrical housing 110, an electrode assembly 120, and a cover assembly 130. In some examples, the cover assembly 130 may include or be referred to as a cover, cover group, cover assembly, cover, or lid.

[0029] The cylindrical housing 110 may include a generally circular bottom 111 and sidewalls 112 extending upward from the bottom 111 for a predetermined length. In some examples, the cylindrical housing 110 may include, or be referred to as, a can, an outer material, or a shell.

[0030] During the manufacturing process of the secondary battery, the top of the cylindrical housing 110 can be open. Therefore, during the assembly process of the secondary battery, the electrode assembly 120 can be integrated into a single structure and inserted into the cylindrical housing 110. Of course, electrolyte can be separately injected into the cylindrical housing 110 in a subsequent process.

[0031] The cylindrical shell 110 may be made of steel, steel alloy, nickel-plated steel, nickel-plated steel alloy, aluminum, or aluminum alloy.

[0032] In addition, the cylindrical housing 110 may be provided with a rolled edge portion 113 and a pressing portion 114. The rolled edge portion 113 is recessed inward at the lower part of the cover assembly 130 to prevent the cover assembly 130 from falling outward, and the pressing portion 114 is bent inward at the upper part of the cover assembly 130.

[0033] Electrode assembly 120 may be housed within cylindrical housing 110. Electrode assembly 120 may include, or be referred to as, an electrode, an electrode assembly, or a jelly roll. Electrode assembly 120 may include a negative electrode plate 121 coated with a negative electrode active material (e.g., graphite, carbon, etc.), a positive electrode plate 122 coated with a positive electrode active material (e.g., transition metal oxides (LiCoO2, LiNiO2, LiMn2O4, etc.)), and a separator 123 located between the negative electrode plate 121 and the positive electrode plate 122 to prevent short circuits and allow only lithium ion movement. The negative electrode plate 121, the positive electrode plate 122, and the separator 123 may be wound into a generally cylindrical shape. In some examples, the negative electrode plate 121 may be a copper (Cu) foil, the positive electrode plate 122 may be an aluminum (Al) foil, and the separator 123 may be polyethylene (PE) or polypropylene (PP).

[0034] Additionally, the negative electrode contact 124, which protrudes downward and extends to a certain length, can be welded to the negative electrode plate 121, and the positive electrode contact 125, which protrudes upward and extends to a certain length, can be welded to the positive electrode plate 122. Furthermore, the negative electrode contact 124 can be made of copper (Cu) or nickel (Ni), and the positive electrode contact 125 can be made of aluminum (Al).

[0035] Additionally, the negative terminal 124 of the electrode assembly 120 can be soldered to the bottom 111 of the cylindrical housing 110. Therefore, the cylindrical housing 110 can function as the negative electrode. In some examples, the negative terminal 124 can be ultrasonically welded or laser-welded to the bottom 111 of the cylindrical housing 110. Conversely, the positive terminal 125 can be soldered to the bottom 111 of the cylindrical housing 110, and in this case, the cylindrical housing 110 can function as the positive electrode.

[0036] Additionally, a first insulating plate 126, incorporated into the cylindrical housing 110 and having a first hole 126a at the center and a second hole 126b at the center exterior, can be inserted between the electrode assembly 120 and the bottom 111. In some examples, the first insulating plate 126 prevents the electrode assembly 120 from making electrical contact with the bottom 111 of the cylindrical housing 110. In some examples, when a large amount of gas is generated due to an anomaly in the secondary battery, the first hole 126a allows the gas to move rapidly upward through the center pin 140, and the second hole 126b allows the negative terminal piece 124 to pass through and be soldered to the bottom 111.

[0037] Additionally, a second insulating plate 127, incorporated into the cylindrical housing 110 and having a first hole 127a at its center and a plurality of second holes 127b outside the center, can be inserted between the electrode assembly 120 and the cover assembly 130. In some examples, the second insulating plate 127 prevents the electrode assembly 120 from electrically contacting the cover assembly 130. In some examples, the second insulating plate 127 prevents the negative electrode plate 121 of the electrode assembly 120 from electrically contacting the cover assembly 130. In some examples, when a large amount of gas is generated due to an anomaly in the secondary battery, the first hole 127a allows the gas to move rapidly into the cover assembly 130, and one of the second holes 127b allows the positive electrode tab 125 to pass through and be soldered to the cover assembly 130. Furthermore, the remaining second holes 127b are used to allow electrolyte to flow rapidly into the electrode assembly 120 during the electrolyte injection process.

[0038] In addition, the diameters of the first hole 126a of the first insulating plate 126 and the first hole 127a of the second insulating plate 127 are formed to be smaller than the diameter of the center pin 140, thereby preventing the center pin 140 from making electrical contact with the bottom 111 of the cylindrical housing 110 or the cover assembly 130 due to external impact.

[0039] The center pin 140 has a hollow circular tube shape and can be attached to the center of approximately the electrode assembly 120. The center pin 140 can be made of steel, stainless steel, aluminum, aluminum alloy, or polybutylene terephthalate, but the material is not limited to these. The center pin 140 is used to suppress deformation of the electrode assembly 120 during charging and discharging of the secondary battery and serves as a channel for gases generated inside the secondary battery. In some cases, the center pin 140 can be omitted.

[0040] The cover assembly 130 can seal the opening of the cylindrical housing 110 to protect the electrode assembly 120 from the external environment, and when the internal pressure of the cylindrical housing 110 is higher than a reference pressure, the cover assembly 130 can rupture to release the internal gas of the cylindrical housing 110 to the outside. In some examples, the cover assembly 130 can also be used as a positive terminal.

[0041] The cover assembly 130 may include an upper cover 131 having multiple through holes 131a, an exhaust plate 132 mounted below the upper cover 131, a lower cover 133 mounted below the exhaust plate 132 and having multiple through holes 133a, an insulator 134 inserted between the exhaust plate 132 and the lower cover 133, a terminal plate 135 mounted above the upper cover 131, a first insulating washer 136 inserted between the terminal plate 135 and the upper cover 131, and a second insulating washer 137 inserted between the lower cover 133 and the cylindrical housing 110.

[0042] The top cover 131 may protrude upward at its center to serve as a terminal for electrical connection to an external device. In some examples, the top cover 131 may serve as a positive terminal. When abnormal internal pressure occurs inside the cylindrical housing 110 due to overcharging or the like, the plurality of through holes 131a provided in the top cover 131 may be used to vent internal gases to the outside. In some examples, the top cover 131 may include, or be referred to as, a cover, conductor plate, covering, or lid. In some examples, the top cover 131 may be made of aluminum or an aluminum alloy.

[0043] The vent plate 132 may be located below the cover 131. In some examples, the vent plate 132 may be tightly attached to, contact with, bonded to, or connected to the lower part of the cover 131. Specifically, except for the upwardly projecting center of the cover 131, the vent plate 132 may be tightly attached to, contact with, bonded to, or connected to the edge of the cover 131. In some examples, the vent plate 132 may include or be referred to as a safety vent, safety plate, vent, valve, sheet, or conductor plate. In some examples, the vent plate 132 may be made of aluminum or an aluminum alloy.

[0044] The vent plate 132 may also include a notch 132a formed at a predetermined depth on its upper surface. In some examples, the notch 132a may be located at a position corresponding to the through hole 133a of the lower cover 133. In some examples, when the internal pressure of the secondary battery is greater than the reference pressure (or the rupture pressure of the vent plate), the notch 132a may rupture due to the internal gas, allowing the internal gas of the cylindrical housing 110 to be released to the outside through the through hole 131a of the upper cover 131, thus ensuring the safety of the secondary battery.

[0045] The lower cover 133 can be tightly attached to, contact with, bonded to, or connected to the lower part of the exhaust plate 132. The lower cover 133 can be electrically connected to the electrode assembly 120 via a positive terminal 125. The positive terminal 125 of the electrode assembly 120 can be welded to the lower surface of the lower cover 133. In some examples, the lower surface of the lower cover 133 can be ultrasonically welded and / or laser welded to the positive terminal 125. In some examples, the lower cover 133 can be made of aluminum or an aluminum alloy.

[0046] In some examples, when the internal pressure of the secondary battery is greater than the reference pressure (or the rupture pressure of the vent plate), the vent plate 132 will deform due to the internal gas, and the lower cover 133 and the vent plate 132 will electrically separate.

[0047] An insulator 134 may be located between the edge of the exhaust plate 132 and the edge of the lower cover 133. The insulator 134 serves to insulate the lower cover 133 and the exhaust plate 132 from each other when the exhaust plate 132 deforms due to internal gas. In some examples, the insulator 134 may be made of a resin material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc., but the material is not limited to these.

[0048] Terminal plate 135 may be positioned above the edge of cover 131. Terminal plate 135 may have a centrally formed hole, allowing the center projecting upward from cover 131 to be exposed to the outside. In some examples, terminal plate 135 may be formed in a ring shape. Terminal plate 135 may be spaced apart from the center of cover 131. Additionally, terminal plate 135 may be insulated from cover 131 by a first insulating washer 136.

[0049] In some examples, the area of ​​the terminal plate 135 may correspond to the area of ​​the edge of the cover 131. Additionally, the terminal plate 135, serving as the negative terminal, may be exposed in the same direction as the center of the cover 131, which serves as the positive terminal. Therefore, the secondary battery 100 according to this disclosure can be easily coupled to or soldered to the positive and negative terminals of an external device (or battery pack).

[0050] Reference Figure 3A A first insulating washer 136 may be inserted between the upper cover 131 and the terminal plate 135 to insulate the upper cover 131 and the terminal plate 135 from each other. The first insulating washer 136 may have an annular shape with a hole formed in the center. In some examples, a second insulating washer may be formed to have an area larger than the area of ​​the edges of the terminal plate 135 and the upper cover 131.

[0051] The lower surface of the first insulating washer 136 can contact or be tightly attached to the edge of the upper cover 131 and the second insulating washer 137, and the upper surface of the first insulating washer 136 can contact or be tightly attached to the terminal block 135. The outer surface of the first insulating washer 136 can contact or be tightly attached to the cylindrical housing 110.

[0052] In some examples, the first insulating gasket 136 may include, or be referred to as, a sealing gasket, an insulator, or a resin. The first insulating gasket 136 may be made of a resin material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc., but the material is not limited thereto.

[0053] Reference Figure 3B The first insulating washer 136 may further include an extension 136a that extends upward and covers the side surface of the terminal plate 135. The extension 136a may be located on both edges of the first insulating washer 136 to cover the inner and outer surfaces of the terminal plate 135. In this way, the first insulating washer 136 can prevent the terminal plate 135 from contacting the cover 131.

[0054] The second insulating washer 137 can be inserted between the cylindrical housing 110 and the upper cover 131, the vent plate 132, and the lower cover 133. The second insulating washer 137 can cover the outer periphery of the upper cover 131, the vent plate 132, and the lower cover 133. The second insulating washer 137 can be made of resin materials such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc., but the material is not limited to these.

[0055] The second insulating gasket 137 can be in close contact with the rolled edge 113, and the inner surface of the second insulating gasket 137 can be in close contact with the edges of the upper cover 131, the vent plate 132, and the lower cover 133. In some examples, the second insulating gasket 137 may include or be referred to as a sealing gasket, an insulator, or a resin. The second insulating gasket 137 may be made of resin materials such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc., but the material is not limited to these.

[0056] Figure 4 This is a cross-sectional view showing a secondary battery according to another embodiment of the present disclosure.

[0057] Reference Figure 4 According to another embodiment of the present disclosure, the secondary battery 200 may include a cylindrical housing 210, an electrode assembly 120, and a cover assembly 230.

[0058] The cylindrical housing 210 may include a generally circular bottom 111, a side wall 112 extending upward from the bottom 111 for a certain length, and a notch 215 provided on the bottom 111.

[0059] The notch 215 may be formed to a certain depth on the lower surface of the bottom 111. In some examples, the notch 215 may be provided on the upper surface of the bottom 111, or on both the upper and lower surfaces of the bottom 111. The notch 215 may be located outside the portion of the bottom 111 to which the negative terminal piece 124 is soldered. The notch 215 may be formed continuously on the bottom 111. In some examples, the notch 215 may include a plurality of notches formed at specific intervals in the bottom 111.

[0060] In some examples, when the internal pressure of the secondary battery is higher than the reference pressure, the notch 215 can rupture to release the internal gas of the cylindrical housing 110 to the outside (lower side), thus ensuring the safety of the secondary battery. In addition, when the notch 215 ruptures, the negative terminal piece 124 and the side wall 112 of the cylindrical housing 110 can be electrically separated, thereby blocking the flow of current to the terminal plate 135.

[0061] The cover assembly 230 may include an upper cover 131 having multiple through holes 131a, a lower cover 133 mounted below the upper cover 131, a terminal plate 135 mounted above the upper cover 131, a first insulating washer 136 inserted between the terminal plate 135 and the upper cover 131, and a second insulating washer 137 inserted between the lower cover 133 and the cylindrical housing 210.

[0062] Figure 4 The cover assembly 230 shown may have from Figure 2 The cover assembly 130 shown omits the structures of the vent plate 132 and the insulator 134. In the secondary battery 200 according to this disclosure, instead of the vent plate 132 and the insulator 134, a recess 215 provided in the cylindrical housing 210 can serve as the vent plate 132 and the insulator 134.

[0063] As described above, the secondary battery according to an embodiment of the present disclosure includes a terminal plate electrically connected to a cylindrical housing and mounted in the same direction as the top cover, thereby facilitating welding to external devices.

[0064] While the foregoing embodiments are merely one example of implementing a secondary battery according to the present disclosure, the present disclosure is not limited to this embodiment, and those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. A secondary battery, the secondary battery comprising: Cylindrical shell; The electrode assembly is housed within the cylindrical housing; as well as A cover assembly that seals the cylindrical housing and includes a top cover electrically connected to the positive electrode of the electrode assembly, a terminal plate above the edge of the top cover, and a first insulating gasket inserted between the edge of the top cover and the terminal plate. The cylindrical housing includes an inwardly bent crimping portion at the upper part of the cover assembly, the crimping portion covering and contacting a portion of the terminal plate such that the terminal plate is electrically connected to the negative terminal piece of the electrode assembly through the crimping portion of the cylindrical housing and serves as the negative terminal of the secondary battery.

2. The secondary battery according to claim 1, wherein, The negative terminal of the electrode assembly is welded to the bottom of the cylindrical housing.

3. The secondary battery according to claim 1, wherein, The cylindrical housing also includes an inwardly recessed rolled edge at the lower part of the cover assembly.

4. The secondary battery according to claim 1, wherein, The terminal block exposes the central portion that protrudes upward from the top cover.

5. The secondary battery according to claim 1, wherein, The area of ​​the terminal block corresponds to the area of ​​the edge of the top cover.

6. The secondary battery according to claim 1, wherein, The first insulating washer is located between the edge of the upper cover and the terminal plate, and the area of ​​the first insulating washer is larger than the area of ​​the terminal plate.

7. The secondary battery according to claim 1, wherein, The first insulating gasket includes an extension that extends upward and covers the side surface of the terminal block.

8. The secondary battery according to claim 1, wherein the secondary battery further comprises a second insulating washer inserted between the upper cover and the cylindrical housing.

9. The secondary battery according to claim 1, further comprising: An exhaust plate is installed under the upper cover and has a notch; The lower cover is installed below the exhaust plate and has multiple through holes; as well as An insulator is inserted between the exhaust plate and the lower cover.

10. The secondary battery according to claim 1, wherein, The cylindrical shell includes a notch on its bottom surface.

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