Title of Invention: Secondary battery and battery pack comprising the secondary battery
technical field
[One]
Cross Citation with Related Applications
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0133212 dated October 24, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[3]
technical field
[4]
The present invention relates to a secondary battery and a battery pack including the secondary battery, and more particularly, to a secondary battery having a structure capable of preventing ignition from occurring when the temperature of the secondary battery rises, and a battery including the secondary battery It's about the pack.
background
[5]
A secondary battery capable of repeatedly charging and discharging may be classified into a pouch type, a prismatic type, and a cylindrical type according to a manufacturing method and structure thereof. For example, a pouch-type secondary battery has a structure in which an electrode assembly is accommodated in a sheet-shaped pouch. These pouch-type secondary batteries have advantages over other types of secondary batteries in terms of simplicity of a manufacturing method and capacity per unit volume, and thus are widely used in various fields.
[6]
On the other hand, the secondary battery has a problem that an explosion or fire may occur in the course of use. For example, when the temperature of the secondary battery is abnormally increased due to abnormal operation of the secondary battery, an explosion or fire may occur.
[7]
Therefore, when the temperature of the secondary battery is abnormally increased, it is necessary to reduce the risk of explosion or fire of the secondary battery by stopping the operation of the secondary battery.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[8]
The problem to be solved by the present invention is to prevent explosion or fire of the secondary battery by inducing a short circuit in the secondary battery when the temperature of the secondary battery is abnormally increased.
means of solving the problem
[9]
According to one aspect of the present invention for achieving the above object, an electrode assembly having a structure in which a positive electrode, a separator, a negative electrode and a separator are alternately arranged, and including a positive electrode tab protruding from the positive electrode and a negative electrode tab projecting from the negative electrode ; a casing for accommodating the electrode assembly; and a short circuit unit accommodated in the exterior material and having electrical conductivity. including, wherein the short-circuiting part is attached to the separator in the electrode assembly, the short-circuiting part is spaced apart from the positive electrode tab and the negative electrode tab below a predetermined temperature, and the short-circuiting part is the separator to which the short-circuiting part is attached above the predetermined temperature. There is provided a secondary battery electrically connecting the positive electrode tab and the negative electrode tab by contacting the positive electrode tab and the negative electrode tab by contraction.
[10]
The positive electrode tab may protrude from one side of the electrode assembly, and the negative electrode tab may protrude from the other side of the electrode assembly.
[11]
The shorting part may be attached to one of a plurality of separators in the electrode assembly.
[12]
The shorting part may be attached to two or more of the plurality of separators in the electrode assembly.
[13]
The shorting part may be attached along the circumference of the separator in the electrode assembly.
[14]
The short-circuiting part is provided in plurality, and one of the plurality of short-circuiting parts is attached along one periphery of the separator to which the short-circuiting part is attached, and the other of the plurality of short-circuiting parts is around the other side of the separator to which the short-circuiting part is attached. It can be attached along
[15]
The shorting part may be provided to be spaced inwardly from the exterior material.
[16]
The negative electrode tab may protrude from the other side of the electrode assembly formed opposite to the one side of the electrode assembly.
[17]
The negative electrode tab may protrude from the other side of the electrode assembly formed adjacent to the one side of the electrode assembly.
[18]
Below the predetermined temperature and above the predetermined temperature, the short circuit portion may be spaced apart from the positive electrode and the negative electrode in the electrode assembly.
[19]
At less than the predetermined temperature, the short-circuiting part extends from a position spaced apart from the positive electrode tab by a first interval D1 to a position spaced apart from the negative electrode tab by a second interval D2, and above the predetermined temperature, the short-circuiting part The length at which the attached separator is contracted in a direction parallel to the first gap D1 is greater than the first gap D1, and the separator to which the short circuit is attached is separated from the second gap D2 at the predetermined temperature or higher. A length contracted in a parallel direction may be greater than the second interval D2.
[20]
The exterior material may be a pouch-type sheet exterior material.
[21]
According to another aspect of the present invention for achieving the above object, there is provided a battery pack including a plurality of secondary batteries according to claim 1 .
Effects of the Invention
[22]
According to the present invention, when the temperature of the secondary battery is abnormally increased, it is possible to prevent explosion or fire of the secondary battery by inducing a short circuit in the secondary battery.
Brief description of the drawing
[23]
1 is a plan view illustrating a state in which a secondary battery according to a first embodiment of the present invention is operating normally.
[24]
2 is a plan view illustrating a case in which the temperature of the secondary battery according to the first embodiment of the present invention is abnormally increased.
[25]
3 is a plan view illustrating a state in which the secondary battery according to the second embodiment of the present invention is operating normally.
[26]
4 is a plan view illustrating a case in which the temperature of the secondary battery according to the second embodiment of the present invention is abnormally increased.
[27]
5 is a plan view illustrating a state in which the secondary battery according to the third embodiment of the present invention is operating normally.
[28]
6 is a plan view illustrating a case in which the temperature of the secondary battery according to the third embodiment of the present invention is abnormally increased.
Best mode for carrying out the invention
[29]
Hereinafter, the structure of the secondary battery according to the present invention will be described with reference to the drawings.
[30]
[31]
secondary battery
[32]
1 is a plan view illustrating a case in which a secondary battery according to a first embodiment of the present invention is operating normally, and FIG. 2 is a case in which the temperature of the secondary battery according to the first embodiment of the present invention rises abnormally. It is a floor plan showing the appearance.
[33]
1 and 2 , the secondary battery according to the present invention may include an electrode assembly 100 . The electrode assembly 100 may have a structure in which an anode, a separator, a cathode, and a separator are alternately disposed in a thickness direction.
[34]
Meanwhile, the electrode assembly 100 may include a positive electrode tab 110a protruding from the positive electrode and a negative electrode tab 120a projecting from the negative electrode. The positive electrode tab 110a may protrude from one side of the electrode assembly 100 , and the negative electrode tab 120a may protrude from the other side of the electrode assembly 100 . 1 and 2 , the positive electrode tab 110a protrudes from one side of the electrode assembly 100 (the upper side of the electrode assembly with reference to FIGS. 1 and 2 ), and the negative electrode tab 120a has the positive electrode tab protruding therefrom. A state in which the electrode assembly protrudes from the other side (the lower side of the electrode assembly with reference to FIGS. 1 and 2 ) formed on the opposite side of one side of the electrode assembly is illustrated.
[35]
In addition, the secondary battery according to the present invention may further include a casing (not shown) for accommodating the electrode assembly 100 . The exterior material may be a pouch-type sheet exterior material. That is, the secondary battery according to the present invention may be a pouch-type secondary battery. However, the secondary battery according to the present invention is not limited to a pouch-type secondary battery and may be applied to various types of secondary batteries.
[36]
Continuing to refer to FIGS. 1 and 2 , the secondary battery according to the present invention may further include a short circuit 200 having electrical conductivity. The short circuit unit 200 may be configured to be accommodated in the exterior material of the secondary battery.
[37]
The short circuit 200 according to the present invention may be attached to the separator of the electrode assembly 100 .
[38]
As used herein, 'the shorting part is attached to the separator of the electrode assembly' means that when a predetermined adhesive force is formed between the short circuit part and the separator, and the separator contracts or expands in the region where the adhesive force is formed between the short circuit part and the separator, the shape of the short circuit part also depends accordingly. It may mean to contract or expand.
[39]
The short circuit part 200 may be attached along the circumference of the separator in the electrode assembly 100 .
[40]
Meanwhile, in the secondary battery according to the present invention, the size of the separator may be larger than that of the positive electrode and the negative electrode. Accordingly, a region not facing the anode and the cathode may be formed around the separator. Accordingly, the shorting part 200 may be attached along a region of the periphery of the separator in the electrode assembly 100 that does not face the anode and the cathode.
[41]
As described above, the short-circuiting part 200 may have electrical conductivity. When the short-circuiting part 200 is attached to a region facing the anode or the cathode in the separator, the short-circuiting part may directly contact the anode or the cathode. In this case, the performance of the secondary battery may be adversely affected.
[42]
The operating principle of the short circuit unit 200 in the secondary battery according to the present invention will be described as follows.
[43]
When the temperature in the secondary battery is less than a predetermined temperature, the short circuit part 200 may be spaced apart from the positive electrode tab 110a and the negative electrode tab 120a.
[44]
Then, when the temperature in the secondary battery exceeds a predetermined temperature, the separators in the electrode assembly contract. This may result from shrinkage of the separator when the separator is exposed to an abnormal high temperature due to the characteristics of the material.
[45]
That is, the separator is usually made of a polymer material such as polyethylene or polypropylene, and the polymer material shrinks while melting at a high temperature. It can be seen that the present invention utilizes the characteristics at high temperature of a separator made of a polymer material such as polyethylene or polypropylene.
[46]
Accordingly, the shorting part 200 comes into contact with the positive electrode tab 110a and the negative electrode tab 120a, respectively, due to the contraction of the separator to which the short circuit part 200 is attached, so that the positive electrode tab 110a and the negative electrode tab 120a are connected to the short circuit part. (200) is electrically connected. Due to this, a short circuit occurs between the positive electrode and the negative electrode, and thus the secondary battery is discharged, and thus the temperature increase of the secondary battery may be stopped.
[47]
Meanwhile, the electrode assembly 100 may include a plurality of separators. According to an example of the present invention, the short circuit 200 may be attached to only one of the plurality of separators in the electrode assembly 100 . However, according to another example of the present invention, the short circuit part 200 may be attached to two or more of the plurality of separators in the electrode assembly 100 . According to the above example of the present invention, since the shorting part 200 only needs to be attached to one separator, the simplification of the process can be achieved. On the other hand, according to the other example of the present invention, even if the short circuit part 200 is separated from one of the plurality of separators, it can still be attached to the other separator, so that the short circuit part 200 can operate normally.
[48]
Meanwhile, as described above, when the short circuit part 200 directly contacts the positive or negative electrode of the electrode assembly 100 , the performance of the secondary battery may be adversely affected. Therefore, according to the present invention, the short circuit part 200 may be spaced apart from the positive electrode and the negative electrode in the electrode assembly 100 regardless of the temperature of the secondary battery. That is, according to the present invention, below the predetermined temperature and above the predetermined temperature, the short circuit part 200 may be spaced apart from the positive electrode and the negative electrode in the electrode assembly 100 .
[49]
In addition, when the short circuit part 200 is in direct contact with the exterior material of the secondary battery, a problem in which the exterior material is damaged may occur due to a reaction between the exterior material and the short circuit unit 200 . Therefore, according to the present invention, the short-circuiting part 200 may be provided to be spaced apart from the exterior material of the secondary battery inward.
[50]
Meanwhile, as shown in FIGS. 1 and 2 , according to the first embodiment of the present invention, the short circuit unit 200 may be provided in a single number. 1 and 2 show a state in which one shorting part 200 is attached along one periphery of the separator.
[51]
3 is a plan view illustrating a case in which the secondary battery according to the second embodiment of the present invention is operating normally, and FIG. 4 is a case in which the temperature of the secondary battery according to the second embodiment of the present invention is abnormally increased. It is a plan view showing the
[52]
According to the second embodiment of the present invention, a plurality of short circuit units 200 may be provided in the secondary battery. 3 and 4 show a state in which two short-circuit parts 200 are provided. The separation membrane to which the two short-circuit parts 200 are attached may be the same as each other.
[53]
At this time, as shown in FIGS. 3 and 4 , one of the two short-circuiting parts 200 may be attached along the circumference of one side of the separator to which the short-circuiting part 200 is attached, and among the two short-circuiting parts 200 , The other one may be attached along the circumference of the other side of the separator to which the short circuit part 200 is attached. However, unlike this, the separation membrane to which the two short circuit parts 200 are respectively attached may be different separation membranes.
[54]
5 is a plan view illustrating a case in which the secondary battery according to the third embodiment of the present invention is operating normally, and FIG. 6 is a case in which the temperature of the secondary battery according to the third embodiment of the present invention rises abnormally. It is a plan view showing the
[55]
Unlike the first and second embodiments of the present invention, according to the third embodiment of the present invention, the negative electrode tab 120a is one side of the electrode assembly from which the positive electrode tab 110a protrudes (see FIGS. 5 and 6 ). It may protrude from the other side (the right side of the electrode assembly with reference to FIGS. 5 and 6 ) formed adjacent to the upper side of the electrode assembly as a reference. In addition, the shorting part 200 may be attached along the periphery of the shortest distance connecting the positive electrode tab 110a and the negative electrode tab 120a among the circumferences of the separator of the electrode assembly. Accordingly, according to the third exemplary embodiment of the present invention, the shorting part 200 may have an approximately L-shape.
[56]
On the other hand, as described above, according to the present invention, the short-circuiting part 200 is spaced apart from the positive electrode tab 110a and the negative electrode tab 120a below a predetermined temperature, and at a predetermined temperature or higher, the short-circuiting portion 200 is the positive electrode. It may contact the tab 110a and the negative electrode tab 120a.
[57]
Accordingly, as shown in FIGS. 1, 3, and 5, the short circuit part 200 is separated from the positive electrode tab 110a by a first distance D1 at a temperature below a predetermined temperature by the negative electrode tab 120a and the second electrode tab 120a. It may be attached to the separator in a state of being extended to a position spaced apart by two intervals (D2).
[58]
Then, when the separator is contracted at a temperature higher than a predetermined temperature, a length in which the separator to which the shorting part 200 is attached is contracted in a direction parallel to the first gap D1 may be greater than the first gap D1 . This is to allow the short circuit part 200 to contact the positive electrode tab 110a at a predetermined temperature or higher.
[59]
Similarly, when the separator contracts at a temperature higher than a predetermined temperature, a length in which the separator to which the short circuit part 200 is attached contracts in a direction parallel to the second gap D2 may be greater than the second gap D2 . This is to allow the short circuit part 200 to contact the negative electrode tab 120a at a predetermined temperature or higher.
[60]
[61]
battery pack
[62]
The battery pack according to the present invention may include a plurality of secondary batteries including a short circuit. The contents of the short circuit part and the secondary battery are replaced with the above contents.
[63]
On the other hand, at least some of the plurality of secondary batteries constituting the battery pack according to the present invention may share one short-circuit portion with each other. That is, according to the present invention, one shorting part may be attached to the separators in different secondary batteries, respectively. In this case, when the temperature of the battery pack or the secondary battery rises abnormally, the short circuit causes a short circuit between the positive electrode and the negative electrode, and the use of the short circuit part can be minimized. can be advantageous
[64]
[65]
In the above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is described below with the technical idea of ​​the present invention by those of ordinary skill in the art to which the present invention pertains. It goes without saying that various implementations are possible within the equivalent scope of the claims.
[66]
[Explanation of code]
[67]
100: electrode assembly
[68]
110a: positive electrode tab
[69]
120a: negative electrode tab
[70]
200: short circuit
Claims
[Claim 1]
an electrode assembly having a structure in which a positive electrode, a separator, a negative electrode, and a separator are alternately disposed, the electrode assembly including a positive electrode tab protruding from the positive electrode and a negative electrode tab projecting from the negative electrode; a casing for accommodating the electrode assembly; and a short circuit unit accommodated in the exterior material and having electrical conductivity. including, wherein the short-circuiting part is attached to the separator in the electrode assembly, the short-circuiting part is spaced apart from the positive electrode tab and the negative electrode tab below a predetermined temperature, and the short-circuiting part is the separator to which the short-circuiting part is attached above the predetermined temperature. A secondary battery electrically connecting the positive electrode tab and the negative electrode tab by contacting the positive electrode tab and the negative electrode tab by contraction.
[Claim 2]
The rechargeable battery of claim 1 , wherein the positive electrode tab protrudes from one side of the electrode assembly, and the negative electrode tab protrudes from the other side of the electrode assembly.
[Claim 3]
The secondary battery of claim 1 , wherein the short circuit part is attached to one of a plurality of separators in the electrode assembly.
[Claim 4]
The secondary battery of claim 1 , wherein the short circuit part is attached to at least two of a plurality of separators in the electrode assembly.
[Claim 5]
The secondary battery of claim 1 , wherein the short circuit part is attached along a circumference of a separator in the electrode assembly.
[Claim 6]
The method according to claim 5, The short-circuit part is provided in plurality, one of the plurality of short-circuiting part is attached along a circumference of one side of the separator to which the short-circuiting part is attached, and the other of the plurality of short-circuiting parts is a separator to which the short-circuiting part is attached. A secondary battery attached along the circumference of the other side of the
[Claim 7]
The secondary battery of claim 1 , wherein the short circuit part is provided to be spaced apart from the exterior material inward.
[Claim 8]
The secondary battery of claim 2 , wherein the negative electrode tab is formed on the opposite side of the one side of the electrode assembly and protrudes from the other side of the electrode assembly.
[Claim 9]
The secondary battery of claim 2 , wherein the negative electrode tab protrudes from the other side of the electrode assembly formed adjacent to the one side of the electrode assembly.
[Claim 10]
The secondary battery of claim 1 , wherein the short circuit part is spaced apart from the positive electrode and the negative electrode in the electrode assembly at less than the predetermined temperature and above the predetermined temperature.
[Claim 11]
The method according to claim 5, wherein the short-circuiting portion is less than the predetermined temperature, doedoe extending from a position spaced apart from the positive electrode tab by a first interval (D1) to a position spaced apart from the negative electrode tab by a second interval (D2), above the predetermined temperature The length in which the separator to which the short circuit is attached is contracted in a direction parallel to the first gap D1 is greater than the first gap D1, and the separator to which the shorting part is attached at a temperature above the predetermined temperature contracts the second gap A secondary battery having a length contracted in a direction parallel to (D2) is greater than the second interval (D2).
[Claim 12]
The secondary battery of claim 1, wherein the exterior material is a pouch-type sheet exterior material.
[Claim 13]
A battery pack comprising a plurality of secondary batteries according to claim 1 .