Title of the invention: Cylindrical battery and battery pack comprising same
technical field
[One]
Cross-Citation with Related Application(s)
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0122562 on October 2, 2019 and Korean Patent Application No. 10-2020-0118906 on September 16, 2020, All content disclosed in the literature is incorporated as a part of this specification. The present invention relates to a cylindrical battery and a battery pack including the same.
background
[3]
Recently, an increase in the price of an energy source due to the depletion of fossil fuels, interest in environmental pollution is amplified, and the demand for an eco-friendly alternative energy source is becoming an indispensable factor for future life. Accordingly, research on various power generation technologies such as nuclear power, solar power, wind power, and tidal power is continuing, and power storage devices for using the generated energy more efficiently are also of great interest.
[4]
Furthermore, as technology development and demand for mobile devices and battery vehicles increase, the demand for batteries as an energy source is rapidly increasing, and accordingly, a lot of research on batteries capable of meeting various needs is being conducted. In particular, in terms of materials, there is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries having advantages such as high energy density, discharge voltage, and output stability.
[5]
Secondary batteries are classified according to the structure of an electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are stacked. Typically, a jelly-roll type (winding type) electrode assembly in which a long sheet-shaped positive electrode and a negative electrode are wound with a separator interposed therebetween, and a plurality of positive and negative electrodes cut in units of a predetermined size with a separator interposed therebetween. and stacked (laminated) electrode assemblies stacked in sequence, and the like. Recently, in order to solve the problems of the jelly-roll type electrode assembly and the stack type electrode assembly, the jelly-roll type and the stack type are mixed. As an electrode assembly having an advanced structure, a stack/folding electrode assembly having a structure in which unit cells in which positive and negative electrodes of a predetermined unit are stacked with a separator interposed therebetween are sequentially wound on a separation film has been developed.
[6]
According to the purpose of use, these electrode assemblies are accommodated in a pouch case, a cylindrical can, and a prismatic case to manufacture a battery.
[7]
Among them, the cylindrical battery is easy to manufacture and has the advantage of high energy density per weight, and thus is used as an energy source for various devices ranging from portable computers to battery vehicles.
[8]
1 and 2 are schematic views showing a process of folding the positive electrode tab of a conventional cylindrical battery.
[9]
1 and 2 , the conventional cylindrical battery 30 folds the positive electrode tab 31 using the jig 11 and the folding knife 12 of the cylindrical battery manufacturing apparatus. The positive electrode tab 31 is welded to the connection part 33 of the top cap 32 , and the jig 11 located on one side of the top cap 32 is moved in the first direction A to press the top cap 32 . At the same time, the folding knife 12 located on the other side of the top cap 32 is moved in the second direction B to press the bent portion 34 . The jig 11 and the folding knife 12 are spaced apart from each other by a height H.
[10]
In general, since the positive electrode tab 31 has a thin strip shape with a thickness of about 0.05 millimeter to 0.3 millimeter, the bending area 34 is pressed by the folding knife 12 and when bent, the physical durability of the bent area 34 . and the stiffness is weakened. Accordingly, there is a problem in that the bent portion 34 is disconnected when a strong stress or continuous stress is applied to the bent portion 34 due to external vibration.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[11]
An object of the present invention is to provide a cylindrical battery capable of preventing disconnection of a positive electrode tab due to external vibration and a battery pack including the same.
[12]
However, the problems to be solved by the embodiments of the present invention are not limited to the above problems and may be variously expanded within the scope of the technical idea included in the present invention.
means of solving the problem
[13]
The cylindrical battery according to an embodiment of the present invention is a cylindrical battery in which an electrode assembly is built in a battery case, and a top cap is mounted on the electrode assembly, and the top cap and the electrode assembly are electrically connected by a positive electrode tab. connected, and the positive electrode tab may include an extension protruding from a bent portion of the positive electrode tab.
[14]
The positive electrode tab may include a first connection part and a second connection part connected to each other at the bent part.
[15]
One side of the first connection part may be connected to the connection part of the top cap, and the other end of the first connection part may be connected to the bent part.
[16]
One side of the second connection part may be connected to the electrode assembly, and the other end of the second connection part may be connected to the bent part.
[17]
The extension part includes a first bending part bent and extended from an end of the first connection part and a second bending part bent and extended from an end of the second connection part, and the first bending part and the second bending part are mutually exclusive. They can be welded to each other.
[18]
The extension portion may extend in a direction opposite to a direction in which the first connection portion and the second connection portion extend from the bent portion.
[19]
The extension portion may extend in a direction in which the first connection portion and the second connection portion extend from the bent portion, and may be formed between the first connection portion and the second connection portion.
[20]
The extension portion may extend in a direction opposite to a direction in which the first connection portion and the second connection portion extend from the bent portion.
[21]
The extension part may include a stress dispersion inducing part between the first connection part and the second connection part.
[22]
The stress dispersion inducing part may be a notch.
[23]
The stress dispersion inducing part may be formed in a direction in which the extension part extends.
[24]
The positive electrode tab may include two or more extension parts.
[25]
The positive electrode tab may include two or more bent portions.
[26]
The positive electrode tab may have a Z-shape.
[27]
A cylindrical battery pack using the cylindrical battery according to the present invention as a unit cell may be provided.
Effects of the Invention
[28]
As described above, in the cylindrical battery according to the embodiment of the present invention, the concentration of stress in the bent portion can be prevented by forming the extension portion at the bent portion of the positive electrode tab.
Brief description of the drawing
[29]
1 and 2 are schematic views showing a process of folding the positive electrode tab of a conventional cylindrical battery.
[30]
3 is a schematic diagram showing a cylindrical battery according to an embodiment of the present invention.
[31]
4 is a schematic diagram illustrating the positive electrode tab of FIG. 3 .
[32]
5 to 8 are schematic views showing a positive electrode tab according to another embodiment of the present invention.
[33]
9 is a schematic view showing a positive electrode tab according to another embodiment of the present invention.
Modes for carrying out the invention
[34]
Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. The present invention may be embodied in several different forms and is not limited to the embodiments described herein.
[35]
In addition, throughout the specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.
[36]
3 is a schematic diagram showing a cylindrical battery according to an embodiment of the present invention. 4 is a schematic diagram illustrating the positive electrode tab of FIG. 3 .
[37]
3 and 4 , the cylindrical battery 100 may include a top cap 101 , an electrode assembly 102 , and a battery case 103 . The electrode assembly 102 is embedded in the battery case 103 , and a top cap 101 may be mounted on the electrode assembly 102 .
[38]
The positive electrode tab 110 may include an extension part 111 , a first connection part 112 , and a second connection part 113 . One side of the first connection part 112 may be electrically connected to the connection part 104 of the top cap 101 . The other side of the first connection part 112 may have a structure connected to the bent part S. One side of the second connection part 113 may be electrically connected to the electrode assembly 102 . The other side of the second connection part 113 may have a structure connected to the bent part S.
[39]
The extension part 111 may extend in a direction opposite to the direction B in which the first connection part 112 and the second connection part 113 extend in the bent part S. The thickness T of the extension part 111 is not particularly limited, but may be formed to be thicker than the thickness T1 of the first connection part 112 . When the thickness T of the extension part 111 is thicker than the thickness T1 of the first connection part 112 , it becomes easy to distribute the stress concentrated in the bent part S toward the extension part 111 . The thickness T of the extension part 111 is preferably formed within the range of 100% to 600% of the thickness T1 of the first connection part 112 . The second extension part 113 may be formed to have the same thickness as the thickness T1 of the first connection part 112 .
[40]
The length L of the extension part 111 is not particularly limited, but may be formed within a range of 10% to 40% of the diameter (D) of the electrode assembly 102 (see FIG. 3 ).
[41]
With this structure, since the stress to be transmitted to the bent portion S due to an external impact is distributed toward the extension 111 , it is possible to prevent the bent portion S of the positive electrode tab 110 from being disconnected.
[42]
5 is a schematic view showing a positive electrode tab according to another embodiment of the present invention.
[43]
Referring to FIG. 5 , the positive electrode tab 110a may include an extension part 111a, a first connection part 112a, and a second connection part 113a. The extension part 111a may extend in a direction B in which the first connection part 112a and the second connection part 113a extend from the bent part Sa. The extension part 111a may extend between the first connection part 112a and the second connection part 113a.
[44]
6 is a schematic view showing a positive electrode tab according to another embodiment of the present invention.
[45]
Referring to FIG. 6 , the positive electrode tab 110b may include an extension part 111b, a first connection part 112b, and a second connection part 113b. The extension portion 111b may have a structure in which the first connection portion 112b and the second connection portion 113b extend in the opposite direction to the direction B in which the bent portion Sb extends simultaneously.
[46]
With this structure, the stress to be transmitted to the positive electrode tab 110b by an external impact may be simultaneously distributed in the direction B and the opposite direction in which the first connection part 112b and the second connection part 113b extend. .
[47]
7 is a schematic view showing a positive electrode tab according to another embodiment of the present invention.
[48]
Referring to FIG. 7 , the positive electrode tab 110c may include an extension part 111c , a first connection part 112c , and a second connection part 113c . The extension portion 111c may have a structure in which the first connection portion 112c and the second connection portion 113c extend in a direction opposite to the direction B in which the bent portion Sc extends. Also, the extension part 111c may include a stress dispersion inducing part 114 between the first connection part 112c and the second connection part 113c. For example, the stress dispersion inducing part 114 may be a notch. The stress dispersion inducing part 114 may be formed in a direction in which the extension part 111c is formed.
[49]
With this structure, the stress to be transmitted to the positive electrode tab 110c by an external impact may be distributed in the direction in which the stress dispersion inducing part 114 is formed. Through this, the operator can form the stress dispersion inducing part 114 in a specific direction to distribute the stress in a desired direction.
[50]
8 is a schematic view showing a positive electrode tab according to another embodiment of the present invention.
[51]
Referring to FIG. 8 , the positive electrode tab 110d includes a first extension part 111d, a second extension part 111d-1, a first connection part 112d, a second connection part 113d, and a third connection part 115d. may include A first extension part 111d may be formed between the first connection part 112d and the second connection part 113d. A second extension part 111d-1 may be formed between the second connection part 113d and the third connection part 115d. The positive electrode tab 110d may have a Z-shape as a whole.
[52]
The first bent portion S1 may be formed at a portion where the first connecting portion 112d and the second connecting portion 113d are connected. The second bent part S2 may be formed at a portion where the second connection part 113d and the third connection part 115d are connected.
[53]
The first extension portion 111d may have a structure in which the first connection portion 112d extends in a direction opposite to the extending direction B. The second extension portion 111d - 1 may have a structure in which the first connection portion 112d extends in the extending direction (B).
[54]
With this structure, the stress to be transmitted to the positive electrode tab 110d due to an external impact may be dispersed to the first extension part 111d and the second extension part 111d-1 and quickly removed.
[55]
9 is a schematic view showing a positive electrode tab according to another embodiment of the present invention.
[56]
Referring to FIG. 9 , the positive electrode tab 110e includes a first extension part 111e, a second extension part 111e-1, a first connection part 112e, a second connection part 113e, and a third connection part 115e. may include A first extension part 111e may be formed between the first connection part 112e and the second connection part 113e. A second extension part 111e-1 may be formed between the second connection part 113e and the third connection part 115e. The positive electrode tab 110d may have a Z-shape as a whole.
[57]
The first bent portion P1 may be formed at a portion where the first connecting portion 112e and the second connecting portion 113e are connected. The second bent portion P2 may be formed at a portion where the second connecting portion 113e and the third connecting portion 115e are connected.
[58]
The first extension portion 111e includes a first bending portion 112p that is bent and extended from an end of the first connection portion 112e, and a second bent portion 113p that is bent and extended from an end of the second connection portion 113e. may include The first bending part 112p and the second bending part 113p may have a structure in which they extend in a direction opposite to the direction B in which the first connecting part 112e extends. In this case, the first bending part 112p and the second bending part 113p may contact each other and be welded.
[59]
The second extension part 111e-1 may have a structure in which the first connection part 112e extends in the extending direction (B). The second extension part 111e-1 includes a third bending part 113p' that is bent and extended at an end opposite to the end of the second connection part 113e on which the second bending part 113p is formed, and a third connection part ( It may include a fourth bending part 115p that is bent and extended from the end of the 115e. The third bending part 113p' and the fourth bending part 115p may have a structure extending in the direction B in which the first connecting part 112e extends. In this case, the third bending part 113p ′ and the fourth bending part 115p may contact each other and be welded.
[60]
With this structure, the stress to be transmitted to the positive electrode tab 110e due to an external impact may be dispersed to the first extension portion 111e and the second extension portion 111e-1 and quickly removed.
[61]
Although the above-described embodiment has been described based on the case where the positive electrode tab 110e has a Z-shape as a whole, the extension portion 111 of the embodiment of FIG. 4 is related to the first extension portion 111e described in this embodiment. Variations in the description may be applied.
[62]
Meanwhile, one or more cylindrical batteries according to an embodiment of the present invention may be packaged in a pack case to form a battery pack.
[63]
The cylindrical battery or battery pack according to the present embodiment described above may be applied to various devices. Such a device may be applied to transportation means such as an electric bicycle, an electric vehicle, and a hybrid vehicle, but the present invention is not limited thereto and is applicable to various devices that can use a cylindrical battery and a battery pack including the same. It belongs to the scope of the invention.
[64]
Those of ordinary skill in the art to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above content.
[65]
Explanation of symbols
[66]
110, 110a, 110b, 110c, 110d, 110e: positive tab
[67]
111, 111a, 111b, 111c: extension
[68]
111d, 111e: first extension
[69]
111d-1, 111e-1: second extension
[70]
112, 112a, 112b, 112c, 112d, 112e: first connection part
[71]
113, 113a, 113b, 113c, 113d, 113e: second connection part
[72]
114: stress dispersion induction part
[73]
115d, 115e: third connection
[74]
S1, P1: first bent part
[75]
S2, P2: second bent part
[76]
Claims
[Claim 1]
A cylindrical battery in which an electrode assembly is built into a battery case, a top cap is mounted on an upper portion of the electrode assembly, the top cap and the electrode assembly are electrically connected by a positive electrode tab, and the positive electrode tab includes the positive electrode tab Cylindrical battery including an extension protruding from the bent portion.
[Claim 2]
The cylindrical battery of claim 1 , wherein the positive electrode tab includes a first connection part and a second connection part connected to each other at the bent part.
[Claim 3]
The cylindrical battery of claim 2 , wherein one side of the first connection part is connected to the connection part of the top cap, and the other side of the first connection part is connected to the bent part.
[Claim 4]
The cylindrical battery of claim 3 , wherein one side of the second connection part is connected to the electrode assembly, and the other side of the second connection part is connected to the bent part.
[Claim 5]
The method of claim 2, wherein the extension part includes a first bending part bent and extended from an end of the first connection part, and a second bending part bent and extended from an end of the second connection part, and the first bending part and Cylindrical battery in which the second bending portion is welded in contact with each other.
[Claim 6]
The cylindrical battery of claim 2, wherein the extension portion extends in a direction opposite to a direction in which the first connection portion and the second connection portion extend from the bent portion.
[Claim 7]
The cylindrical battery of claim 2, wherein the extension portion extends in a direction in which the first connection portion and the second connection portion extend from the bent portion, and is formed between the first connection portion and the second connection portion.
[Claim 8]
The cylindrical battery of claim 2 , wherein the extension portion extends in a direction opposite to a direction in which the first connection portion and the second connection portion extend from the bent portion.
[Claim 9]
The cylindrical battery of claim 2 , wherein the extension part includes a stress dispersion inducing part between the first connection part and the second connection part.
[Claim 10]
The cylindrical battery according to claim 9, wherein the stress dispersion inducing part is a notch.
[Claim 11]
The cylindrical battery of claim 9 , wherein the stress dispersion inducing part is formed in a direction in which the extension part extends.
[Claim 12]
The cylindrical battery according to claim 1, wherein the positive electrode tab includes at least two of the extension portions.
[Claim 13]
The cylindrical battery according to claim 12, wherein the positive electrode tab includes two or more bent portions.
[Claim 14]
The cylindrical battery according to claim 10, wherein the positive electrode tab has a Z-shape.
[Claim 15]
A battery pack comprising the cylindrical battery according to claim 1 .