Title of the invention: A battery module having a structure capable of preventing overcharging, a battery pack including the same, and a vehicle including the battery pack
technical field
[One]
The present invention relates to a battery module having a structure capable of preventing overcharging, a battery pack including the same, and a vehicle including the battery pack, and more specifically, to a battery module that is deformed according to a potential difference applied between both ends It relates to a battery module having a current blocking member for preventing overvoltage by generating a short circuit in some battery cells constituting the battery module, a battery pack including the same, and a vehicle including the battery pack.
[2]
This application is an application for priority claiming Korean Patent Application No. 10-2019-0083357 filed on July 10, 2019, and all contents disclosed in the specification and drawings of the application are incorporated herein by reference.
background
[3]
Fuse devices currently used in secondary batteries include a positive temperature coefficient thermistor (PTC), a thermal cut-out (TCO), and a thermal fuse. However, the thermal fuse has the disadvantage of being disposable, and although the PTC or TCO can be used repeatedly, the more the operation is repeated, the more its resistance increases, thereby increasing the overall resistance on the circuit.
[4]
In addition, all of the above-mentioned elements are operated by heat generation due to overcurrent. That is, the above-mentioned elements correspond to elements that operate to block the flow of current only when an overcurrent is generated on the circuit current path due to overcharging and the like and the temperature is raised accordingly.
[5]
Therefore, in the case of the above-mentioned elements, it is possible to block the overcurrent by operating only after a situation in which the safety is already threatened due to heat generation, and to block the overcurrent immediately when a cause that can increase the temperature occurs. it cannot be
[6]
In addition, in the case of the above-mentioned elements, since they simply operate according to temperature, it is difficult to use secondary batteries exhibiting high output such as battery packs used in automobiles. That is, in the case of a battery pack for a vehicle, a high c-rate is required, and accordingly, the amount of heat is also large. PTC thermistor (positive temperature coefficient thermistor), TCO (thermal cut-out), Devices such as thermal fuses have a problem in that they may operate prematurely when placed in such a high-temperature environment.
[7]
Therefore, it can be reused and used in an environment where high current flows. Also, if an event that can cause such a temperature rise occurs before the temperature rises, a short circuit is forcibly generated and current is consumed, thereby preventing overcharging. There is a need for a secondary battery to which a device capable of blocking the occurrence of overvoltage caused by an overvoltage is applied in advance.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[8]
The present invention was devised in consideration of the above-described problems, and reversibly generates a short circuit in advance before the temperature of the secondary battery rises due to heat generation due to overcurrent and consumes current, so that the generation of overvoltage can be prevented in advance. to do it for the purpose of work.
[9]
However, the technical problems to be solved by the present invention are not limited to the above problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.
means of solving the problem
[10]
A battery module according to an embodiment of the present invention for solving the above problems includes: a first battery cell and a second battery cell having a positive lead and a negative lead and connected in series with each other; and one side in the longitudinal direction is interposed between the negative lead of the first battery cell and the positive lead of the second battery cell, and the other side in the longitudinal direction is in contact with the positive lead of the first battery cell and the negative lead of the second battery cell. a short-circuit inducing member positioned therebetween; Including, when the potential difference between the negative lead of the first battery cell and the positive lead of the second battery cell is equal to or greater than a reference value, the other end in the longitudinal direction of the short-circuit inducing member is directed toward the negative lead of the second battery cell A bending deformation is caused to come into contact with the negative lead of the second battery cell.
[11]
The short circuit guide member may include: an EAP layer; a first metal layer formed on one side of the EAP layer; and a second metal layer formed on the other side of the EAP layer. may include
[12]
The first metal layer may be electrically connected to a negative lead of the first battery cell, and the second metal layer may be electrically connected to a positive lead of the second battery cell.
[13]
The second metal layer may come into contact with the negative lead of the second battery cell when the short circuit inducing member causes bending deformation to cause a short circuit in the second battery cell.
[14]
The EAP layer may include at least one polymer electrolyte selected from Nafion, polypyrrole, polyaniline, and polythiophene.
[15]
The first metal layer and the second metal layer may include any one metal selected from the group consisting of platinum, gold, silver, and copper.
[16]
The battery module may further include a connecting line electrically connecting the positive lead of the first battery cell and the negative lead of the second battery cell.
[17]
The battery module may further include a PTC element interposed between the first metal layer and the negative lead of the first battery cell and between the second metal layer and the positive lead of the second battery cell.
[18]
[19]
A battery pack according to an embodiment of the present invention for solving the above-described problems includes the battery module according to an embodiment of the present invention as described above. In addition, a vehicle according to an embodiment of the present invention for solving the above-described problems includes the battery pack according to an embodiment of the present invention as described above.
Effects of the Invention
[20]
According to one aspect of the present invention, the occurrence of overvoltage can be prevented in advance by reversibly generating a short circuit in advance and consuming the current before the temperature of the secondary battery rises according to the heat generated by the overcurrent. safety can be ensured.
Brief description of the drawing
[21]
The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the detailed description of the present invention to be described later, so that the present invention is described in such drawings should not be construed as being limited only to
[22]
1 is a view showing a battery module according to an embodiment of the present invention.
[23]
2 is a diagram illustrating a battery cell applied to a battery module according to an embodiment of the present invention.
[24]
3 is a view illustrating a short circuit inducing member and an electrode lead applied to a battery module according to an embodiment of the present invention.
[25]
4 is a view showing bending deformation of the short-circuit inducing member that appears when a potential difference greater than or equal to a reference value is applied to the short-circuit inducing member applied to the battery module according to an embodiment of the present invention.
[26]
5 is a view showing a battery module according to another embodiment of the present invention.
[27]
6 is a diagram illustrating a battery pack according to an embodiment of the present invention.
[28]
7 is a view showing a vehicle according to an embodiment of the present invention.
Best mode for carrying out the invention
[29]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention. Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention and do not represent all the technical spirit of the present invention. It should be understood that there may be equivalents and variations.
[30]
[31]
Hereinafter, the battery module 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4 .
[32]
First, referring to FIG. 1 , the battery module 100 according to an embodiment of the present invention includes a plurality of battery cells 10 and at least one short-circuit inducing member 20 , and additionally a connecting line L It may be implemented in a form that further includes.
[33]
Referring to FIG. 2 together with FIG. 1 , the battery cell 10 includes an electrode assembly (not shown), a positive electrode lead 11 , a negative electrode lead 12 , a cell case 13 , and a sealing tape 14 . do.
[34]
Although not shown in the drawings, the electrode assembly has a form in which a separator is interposed between the positive and negative electrode plates that are alternately repeatedly stacked, and it is preferable that the separators are respectively located on the outermost surfaces of both sides for insulation.
[35]
The negative electrode plate is composed of a negative electrode current collector and a negative electrode active material layer coated on one or both surfaces thereof, and an anode uncoated region on which the negative electrode active material is not coated is formed at one end of the negative electrode uncoated region. It functions as a tab.
[36]
The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer coated on one or both surfaces thereof, and a positive electrode uncoated region not coated with a positive electrode active material is formed at one end of the positive electrode uncoated region. It functions as a tab.
[37]
In addition, the separator is interposed between the negative electrode plate and the positive electrode plate to prevent direct contact between the electrode plates having different polarities, but may be made of a porous material to allow the movement of ions between the negative electrode plate and the positive electrode plate by using the electrolyte as a medium. there is.
[38]
The positive electrode lead 11 is connected to the positive electrode tab by a bonding method such as welding and is drawn out of the cell case 13 . The negative electrode lead 12 is a negative electrode tab by a bonding method such as welding. It is connected to and is drawn out to the outside of the cell case 13 , and is drawn out in the same direction as the positive lead 11 . That is, the battery cell 10 applied to the present invention corresponds to a one-way draw-out type battery cell.
[39]
The cell case 13 extends in the circumferential direction of the accommodating part 13a and the accommodating part 13a for accommodating the electrode assembly (not shown) and is thermally fused with the electrode leads 11 and 12 drawn out. The sealing portion 13b for sealing the cell case 13 includes two regions.
[40]
Although not shown in the drawing, the cell case 13 is sealed by heat-sealing the upper case and the lower case each of which are made of a multi-layered pouch film by sequentially stacking a resin layer/metal layer/resin layer in contact with each other. .
[41]
The sealing tape 14 is attached to the periphery of each of the positive electrode lead 11 and the negative electrode lead 12 and is interposed between the sealing portion 13b of the cell case 13 and the electrode leads 11 and 12 . The sealing tape 14 is disposed between the inner surface of the cell case 13 and the electrode leads 11 and 12 in the region from which the electrode leads 11 and 12 are drawn out of the sealing portion 13b of the cell case 13 . It is a component applied to prevent the sealing of the cell case 13 from being deteriorated due to the low adhesive force.
[42]
At least two or more of these battery cells 10 are provided, and each of the battery cells 10 is connected in series to each other. In the drawing ( FIG. 1 ) of the present invention, a case in which four battery cells 10 are connected in series is exemplarily shown, but the present invention is not limited thereto. That is, a case in which two battery cells 10 are connected in series, a case in which three battery cells 10 are connected in series, or a case in which five or more battery cells 10 are connected in series also fall within the scope of the present invention.
[43]
Hereinafter, in describing the present invention, the first battery cell 10A, the second battery cell 10B, and the third battery are sequentially arranged in the direction from the left to the right of the four battery cells 10 shown in FIG. 1 . The cell 10C and the fourth battery cell 10D will be referred to separately.
[44]
[45]
Referring to FIG. 1 , the short-circuit inducing member 20 is disposed between the negative lead 12 of the first battery cell 10A and the positive lead 11 of the second battery cell 10B, the second battery cell 10B. ) between the negative lead 12 of the third battery cell 10C and the positive lead 11 of the third battery cell 10C and the negative lead 12 of the third battery cell 10C and the positive lead 11 of the fourth battery cell 10D. are interposed between each. In this case, the connecting line L connects between the positive lead 11 of the first battery cell 10A and the negative lead 12 of the second battery cell 10B, and the It connects between the positive lead 11 and the negative lead 12 of the third battery cell 10C, and also the positive lead 11 of the third battery cell 10C and the negative lead of the fourth battery cell 10D ( 12) connect them.
[46]
In the description of the short-circuit inducing member 20, the short-circuit inducing member 20 interposed between the negative lead 12 of the first battery cell 10A and the positive lead 11 of the second battery cell 10B is used. An example will be described.
[47]
The short-circuit inducing member 20 physically connects the opposite electrode leads 11 and 12 of the adjacent battery cells 10A and 10B to each other, but the negative lead of the first battery cell 10A by overcharging. When the potential difference between (12) and the positive lead 11 of the second battery cell 10B becomes greater than or equal to the reference value, the shape is deformed.
[48]
The short-circuit inducing member 20 comes into contact with the negative lead 12 of the second battery cell 10B by this shape deformation, and accordingly, the positive lead 11 and the negative lead of the second battery cell 10B ( 12) is directly connected to cause a short circuit. As such, when the short circuit occurs, the voltage of the second battery cell 10B rapidly drops and the risk of overvoltage due to overcharging can be avoided.
[49]
Referring to FIGS. 3 and 4 , the structure of the short circuit inducing member 20 and its operating principle are shown for inducing a short circuit through shape deformation according to such a potential difference.
[50]
First, referring to FIG. 3 , the short circuit inducing member 20 includes an electro active polymer layer (EAP) 21, a first metal layer 22 formed on one side of the EAP layer 61, and the EAP. It is implemented in a form including the second metal layer 23 formed on the other side of the layer 61 .
[51]
The EAP layer 21, that is, the electroactive polymer layer, corresponds to a layer made of a polymer electrolyte having excellent ion transport properties, and includes, for example, Nafion, polypyrole, polyaniline, and polyC. It may include at least one polymer electrolyte selected from polythiophene.
[52]
The first metal layer 22 and the second metal layer 23 are respectively formed on both surfaces of the EAP layer 21 and may be made of a metal having excellent electrical conductivity. The metal layers 22 and 23 may include, for example, at least one metal selected from platinum (Pt), gold (Au), silver (Ag), and copper (Cu).
[53]
The short-circuit inducing member 20 is deformed when a voltage higher than a reference value is applied through the metal layers 22 and 23 formed on both surfaces of the EAP layer 21 . Referring to FIG. 4 together with FIG. 1 , the short-circuit inducing member 20 disposed between the first battery cell 10A and the second battery cell 10B is the negative lead 12 of the first battery cell 10A. The second metal layer 23 is brought into contact with both the positive lead 11 and the negative lead 12 of the second battery cell 10B by causing a bending deformation in a direction away from it.
[54]
That is, at one end of the short-circuit inducing member 20 in the longitudinal direction, the first metal layer 22 is in contact with the negative lead 12 of the first battery cell 10A, and the second metal layer 23 is 2, which is in contact with the positive lead 11 of the battery cell 10B, the second metal layer 23 at the other end in the longitudinal direction of the short-circuit inducing member 20 by bending deformation is the negative electrode of the second battery cell 10B By coming into contact with the lead 11, a short circuit is generated in the second battery cell 10B.
[55]
[56]
The principle of the bending deformation of the short-circuit inducing member 20 is as follows. For example, the first metal layer 22 is connected to the negative lead 12 of the first battery cell 10A, and the second metal layer 23 is connected to the positive lead 11 of the second battery cell 10B. ), mobile cations present in the polymer electrolyte move in the direction of the negatively charged first metal layer 22 in a state hydrated in water. In this case, the osmotic pressure is caused by an imbalance in ion concentration between the first metal layer 22 and the second metal layer 23, so that the amount of water molecules on the negatively charged first electrode layer 22 side increases, Accordingly, bending deformation in the direction of the second metal layer 23 occurs in the short-circuit guide member 20 .
[57]
A potential difference capable of generating bending deformation of the short-circuit inducing member 20 varies depending on the type of polymer electrolyte constituting the EAP layer 21 used in the short-circuit inducing member 20 . That is, the reference value of the potential difference referred to in this specification may vary depending on the type of polymer electrolyte applied, and accordingly, the safety voltage of the battery cell 10 and the battery module 100 to which the short circuit inducing member 20 is applied. By selecting an appropriate polymer electrolyte according to the range, it is possible to block in advance the occurrence of danger due to overvoltage through rapid short circuit induction when an event such as overcharging of the battery module 100 occurs.
[58]
[59]
Next, with reference to FIG. 5 , the battery module 100 according to another embodiment of the present invention will be described.
[60]
The battery module 100 according to another embodiment of the present invention is different from the battery module 100 according to the embodiment of the present invention described above in that the PTC element 30 is further applied, and other The components are substantially identical.
[61]
Therefore, in describing the battery module 100 according to another embodiment of the present invention, the PTC element 30, which is an additionally applied component, will be mainly described, and detailed description of other overlapping matters will be omitted. decide to do
[62]
The resistance value of the PTC element 30 increases as the temperature rises, and when the temperature reaches the reference temperature or more, the PTC element 30 exhibits an infinite resistance value, effectively blocking the current completely. The PTC element 30 is disposed between the negative lead 12 and the first electrode layer 22 of the first battery cell 10A and the positive lead 11 and the second electrode layer of the second battery cell 10B ( 23) is interposed between In addition, the PTC element 30 is disposed between the negative lead 12 and the first electrode layer 22 of the second battery cell 10B and the positive lead 11 and the second electrode of the third battery cell 10C. interposed between the layers 23 . Similarly, the PCT element 30 is disposed between the negative lead 12 and the first electrode layer 22 of the third battery cell 10C and the positive lead 11 and the second electrode of the fourth battery cell 10D. interposed between the layers 23 .
[63]
In addition, the PTC device 30 may be entirely coated on the first metal layer 22 and the second metal layer 23 of the short-circuit inducing member 20 .
[64]
The PTC element 30, when the short-circuit inducing member 20 operates due to the overvoltage generated in the battery module 100 and a short circuit occurs, blocks the short-circuit current at a reference temperature or higher to ignite/explosion due to overheating, etc. risk can be prevented in advance.
[65]
[66]
Meanwhile, referring to FIG. 6 , the battery pack 200 according to an embodiment of the present invention may be implemented in a form including at least one battery module 100 according to the present invention. In addition, referring to Figure 7, according to an embodiment of the present invention A vehicle may be implemented in a form including the battery pack 200 according to an embodiment of the present invention.
[67]
[68]
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 will be described below with the technical idea of ​​the present invention by those of ordinary skill in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims.
Claims
[Claim 1]
a first battery cell and a second battery cell having a positive lead and a negative lead and connected in series with each other; and one side in the longitudinal direction is interposed in a state of being in contact between the negative lead of the first battery cell and the positive lead of the second battery cell, and the other side in the longitudinal direction is in contact with the positive lead of the first battery cell and the negative lead of the second battery cell. a short-circuit guide member positioned between; Including, when the potential difference between the negative lead of the first battery cell and the positive lead of the second battery cell is equal to or greater than a reference value, the other end in the longitudinal direction of the short-circuit inducing member is directed toward the negative lead of the second battery cell A battery module in contact with the negative lead of the second battery cell by causing a bending deformation.
[Claim 2]
The method of claim 1, wherein the short-circuit guide member comprises: an EAP layer; a first metal layer formed on one side of the EAP layer; and a second metal layer formed on the other side of the EAP layer. A battery module comprising a.
[Claim 3]
The battery according to claim 2, wherein the first metal layer is electrically connected to a negative lead of the first battery cell, and the second metal layer is electrically connected to a positive lead of the second battery cell. module.
[Claim 4]
The battery module according to claim 2, wherein the second metal layer contacts the negative lead of the second battery cell to cause a short circuit in the second battery cell when the short circuit inducing member causes bending deformation.
[Claim 5]
The battery module according to claim 2, wherein the EAP layer comprises at least one polymer electrolyte selected from nafion, polypyrrole, polyaniline, and polythiophene.
[Claim 6]
The battery module according to claim 2, wherein the first metal layer and the second metal layer include any one metal selected from the group consisting of platinum, gold, silver, and copper.
[Claim 7]
The battery module according to claim 1, wherein the battery module further comprises a connecting line electrically connecting the positive lead of the first battery cell and the negative lead of the second battery cell.
[Claim 8]
The method of claim 2, wherein the battery module further comprises a PTC element interposed between the first metal layer and the negative lead of the first battery cell and between the second metal layer and the positive lead of the second battery cell. Characterized by the battery module.
[Claim 9]
A battery pack comprising a battery module according to any one of claims 1 to 8.
[Claim 10]
A motor vehicle comprising the battery pack according to claim 9 .