Title of Invention: Battery pack having a structure capable of preventing overcharging and a vehicle including the same
Technical field
[One]
The present invention relates to a battery pack having a structure capable of preventing overcharging, and to a vehicle including the same, and more specifically, the shape of the battery modules are modified according to the potential difference applied between the two sides to be electrically connected to each other. It relates to a battery pack including a current blocking member capable of blocking current, and a vehicle including the same.
[2]
This application is a priority claim application for Korean Patent Application No. 10-2018-0138451 filed on November 12, 2018, and all contents disclosed in the specification and drawings of the application are incorporated herein by reference.
Background
[3]
Currently, fuse devices used in secondary batteries include a PTC thermistor (positive temperature coefficient thermistor), a thermal cut-out (TCO), and a thermal fuse. However, in the case of a thermal fuse, there is a disadvantage in that it is disposable, and although a PTC or TCO can be used repeatedly, it has a disadvantage in that its resistance increases as the operation is repeated, thereby increasing the overall resistance of the circuit.
[4]
In addition, all of the above-mentioned elements are operated by heat generation due to overcurrent. That is, the above-mentioned devices correspond to devices that operate to block the flow of current only when an overcurrent is generated in the circuit current path due to overcharging and the like, and thus the temperature rises.
[5]
Therefore, in the case of the above-mentioned devices, it is possible to cut off the overcurrent by operating only after a situation where safety is already threatened due to heat generation, and the overcurrent can be cut off as soon as a cause that may increase the temperature occurs. Is not.
[6]
In addition, in the case of the above-mentioned devices, since they simply operate according to temperature, there is a side that is difficult to use for secondary batteries that exhibit high output, such as battery packs used in automobiles. That is, in the case of an automobile battery pack, a high c-rate (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 fuse have a problem in that they can operate too early when placed in such a high temperature environment.
[7]
Therefore, it is necessary to have a secondary battery that is reusable and can be used in an environment where high current flows, and a device that can cut off the current in advance if an event that may cause such temperature rise occurs before the temperature rises. Do.
Detailed description of the invention
Technical challenge
[8]
The present invention, as invented in consideration of the above-described problems, is a battery pack having a structure in which a current blocking member capable of blocking current in advance before the temperature of the battery pack increases due to heat generation due to overcharging of the battery pack, etc. Its purpose is to provide.
[9]
However, the technical problem to be solved by the present invention is not limited to the above-described problem, and other problems that are not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.
Means of solving the task
[10]
A battery pack according to an embodiment of the present invention for solving the above-described problems includes: a battery module assembly including a first battery module and a second battery module; A first connector connected to a first electrode of the first battery module; A second connector connected to a second electrode of the second battery module and disposed to be spaced apart from the first connector; A switch connecting the first connector and the second connector; And a current blocking member connected to one side of the switch in the length direction and causing a bending deformation to turn off the switch when a potential difference formed between both ends of the battery module is greater than or equal to a reference value.
[11]
The battery module may include a plurality of battery cells electrically connected to each other.
[12]
One side of the switch in the longitudinal direction is in contact with the first connector, but is formed as a free end so that the contact state with the first connector can be released by bending deformation of the current blocking member, and the other side in the longitudinal direction of the switch is the It may be formed as a fixed end fixed to the second connector.
[13]
One side of the current blocking member in the longitudinal direction may be a free end whose position can be changed by the bending deformation, and the other side of the current blocking member may be a fixed end that is directly or indirectly fixed to the battery module or the ground.
[14]
The current blocking 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.
[15]
The EAP layer may include at least one polymer electrolyte selected from Nafion, polypyrrole, polyaniline, and polythiophene.
[16]
The first metal layer and the second metal layer may include any one metal selected from the group including platinum, silver, and copper.
[17]
The first metal layer may be electrically connected to a negative electrode of the battery module, and the second metal layer may be electrically connected to a positive electrode of the battery module.
[18]
The current blocking member may be positioned above the switch, and the first metal layer may face the switch.
[19]
The battery pack may further include a non-conductive connection rod connecting the switch and the first metal layer.
[20]
The connection rod may be hinged to the switch and the first metal layer, respectively.
[21]
Meanwhile, a vehicle according to an embodiment of the present invention for solving the above-described problems includes a battery pack according to an embodiment of the present invention as described above.
Effects of the Invention
[22]
According to an aspect of the present invention, in the use of the battery pack, before an event such as overheating and/or explosion of the battery pack due to overcharging of the battery pack occurs, a potential difference greater than a reference value that causes such an event is detected in advance. Thus, it is possible to cut off the current, thereby ensuring safety in the use of the battery pack.
Brief description of the drawing
[23]
1 is a view showing a battery pack according to an embodiment of the present invention.
[24]
FIG. 2 is a diagram illustrating individual battery modules constituting the battery pack shown in FIG. 1.
[25]
3 is a diagram illustrating individual battery cells constituting the battery module shown in FIG. 2.
[26]
4 is a diagram illustrating a current blocking member applied to the battery pack shown in FIG. 1.
[27]
FIG. 5 is a diagram illustrating a state in which the current blocking member causes shape deformation when a potential difference greater than or equal to a reference value is formed between the first metal layer and the second metal layer of the current blocking member shown in FIG. 4.
[28]
6 is a view showing a modified example of a connection structure between the current blocking member and the connecting plate shown in FIG. 1.
[29]
7 is a view showing a vehicle according to an embodiment of the present invention.
Mode for carrying out the invention
[30]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a 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.
[31]
First, an overall configuration of a battery pack according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5.
[32]
1 is a view showing a battery pack according to an embodiment of the present invention, FIG. 2 is a view showing individual battery modules constituting the battery pack shown in FIG. 1, and FIG. 3 is a battery module shown in FIG. It is a figure which shows the individual battery cells which comprise. In addition, FIG. 4 is a view showing a current blocking member applied to the battery pack illustrated in FIG. 1, and FIG. 5 is a potential difference greater than or equal to a reference value between the first metal layer and the second metal layer of the current blocking member illustrated in FIG. 4. In the case where it is formed, it is a figure which shows the mode that the current blocking member causes shape deformation.
[33]
First, referring to FIG. 1, a battery pack according to an embodiment of the present invention includes a plurality of battery modules 100, a first connector 200, a second connector 300, a switch 400, and a current blocking member. It is implemented in a form including 500 and a connection rod 600.
[34]
1 and 2 together, the plurality of battery modules 100 form one battery module assembly electrically connected to each other. The battery module 100 may include a plurality of battery cells 10 connected to each other in series, parallel, or a mixture of series and parallel. In addition, the cell stack formed by electrically connecting the battery cells 10 may be electrically connected to the first electrode terminal 110 and the second electrode terminal 120 formed outside the battery module 100.
[35]
In the drawings of the present invention, a case in which the first electrode terminal 110 is a negative terminal and the second electrode terminal 120 is a positive terminal is illustrated as an example, but the present invention is not limited thereto, and the first electrode terminal It is also possible when (110) is a positive terminal and the second electrode terminal 120 is a negative terminal.
[36]
Referring to FIG. 3, as each battery cell 10 constituting the battery pack, for example, a pouch type battery cell may be applied. Referring to FIG. 3, such a pouch-type battery cell 10 may be implemented in a form including an electrode assembly (not shown), an electrode lead 11, a cell case 12, and a sealing tape 13. .
[37]
Although not shown in the drawings, the electrode assembly has a form in which a separator is interposed between a positive electrode plate and a negative electrode plate that are alternately repeatedly stacked, and it is preferable that separators are respectively positioned for insulation on both outer outer sides.
[38]
The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer coated on one or both sides thereof, and a negative electrode uncoated region is formed at one end of the negative electrode uncoated region, which is not coated with a negative electrode active material. It functions as a tab.
[39]
The positive electrode plate is made of a positive electrode current collector and a positive electrode active material layer coated on one or both surfaces thereof, and a positive electrode uncoated portion is formed at one end of the positive electrode uncoated region, and the positive electrode uncoated region is a positive electrode tab. Functions.
[40]
In addition, the separator is interposed between the negative electrode plate and the positive electrode plate to prevent direct contact between electrode plates having different polarities, but may be made of a porous material in order to allow the movement of ions by using an electrolyte as a medium between the negative electrode plate and the positive electrode plate. have.
[41]
The electrode lead 11 is connected to the electrode tab and is drawn out of the cell case 12. The battery cells 10 adjacent to each other may be electrically connected in series, parallel, or a mixture of series and parallel through the electrode lead 11 to form a single cell stack.
[42]
The cell case 12 is heat-sealed in a state in which the electrode lead 11 is drawn out by extending in the circumferential direction of the receiving portion 12a and the receiving portion 12a accommodating the electrode assembly to seal the cell case 12 The sealing part 12b to be made includes two areas.
[43]
Although not shown in the drawings, the cell case 12 is sealed by heat-sealing the edges of the upper case and the lower case made of a multi-layered pouch film in which a resin layer/metal layer/resin layer is sequentially stacked. .
[44]
The sealing tape 13 is attached around the electrode lead 11 and interposed between the sealing portion 12b of the cell case 12 and the electrode lead 11. The sealing tape 13 is a cell case due to low adhesion between the inner surface of the cell case 12 and the electrode lead 11 in the area where the electrode lead 11 is drawn out of the sealing portion 12b of the cell case 12. It is a component for preventing the sealing property of the case 12 from deteriorating.
[45]
Referring back to FIG. 1, the first connector 200 and the second connector 300 may have a metal plate shape made of a conductive material. The first connector 200 is fastened to the second electrode terminal 120 of the first battery module 100 located on one side of a pair of battery modules 100 adjacent to each other. In addition, the second connector 300 is fastened to the first electrode terminal 110 of the second battery module 100 located on the other side of the pair of battery modules 100 adjacent to each other. The first connector 200 and the second connector 300 are disposed to be spaced apart from each other by a predetermined distance.
[46]
The switch 400 connects a pair of connectors 200 and 300 spaced apart from each other. Specifically, the switch 400 may be installed to connect the upper surfaces of each of the first connector 200 and the second connector 300.
[47]
One side of the switch 400 in the longitudinal direction is in contact with the first connector 200, but moves together when the current blocking member 500 is bent to a free end so that the contact state with the first connector 200 can be released. Is formed. Unlike this, the other side in the longitudinal direction of the switch 400 is formed as a fixed end fixed to the second connector 300 by welding or the like.
[48]
The current blocking member 500 causes bending deformation when the voltage applied on both sides exceeds the reference value, and is connected to the switch 400 by the connection rod 600 to move the switch 400 when bending deformation. Enables to perform an off operation.
[49]
To perform this function, the current blocking member 500 may be disposed above the switch 400. In addition, one side in the length direction of the current blocking member 500 may be formed as a free end whose position can be changed by bending deformation, and the other side in the length direction is directly or indirectly fixed to the battery module 100 or the ground. It can be formed with a fixed end.
[50]
In order to cause the switch 400 to perform an off operation by bending deformation of the current blocking member 500, the connection rod 600 is a free end of the current blocking member 500 and the free end of the switch 400. Connect between stages.
[51]
The connection rod 600 is made of, for example, a plastic material, and both ends thereof may be adhered to the lower surface of the current blocking member 500 and the upper surface of the switch 400, respectively.
[52]
Meanwhile, referring to FIGS. 4 and 5, in order to block overcurrent by shape deformation according to a potential difference formed between both surfaces, the current blocking member 500 includes an EAP layer (Electro active polymer layer) 510), a first metal layer 520 formed on one side of the EAP layer 510, and a second metal layer 530 formed on the other side of the EAP layer 510.
[53]
The EAP layer 510, 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 polyaniline. It may include at least one polymer electrolyte selected from polythiophene.
[54]
The first metal layer 520 and the second metal layer 530 are formed on both surfaces of the EAP layer 510, respectively, and may be made of metal having excellent electrical conductivity. The metal layers 520 and 530 may include, for example, at least one metal selected from platinum (Pt), gold (Au), silver (Ag), and copper (Cu).
[55]
When a voltage higher than a reference value is applied through the metal layers 510 and 520 formed on both surfaces of the EAP layer 510, the current blocking member 500 causes shape deformation.
[56]
That is, the first metal layer 520 is electrically connected to the negative electrode of the battery module 100, and the second metal layer 530 is electrically connected to the positive electrode of the battery module 100 to form a pair of metal layers ( A potential difference equal to the voltage of the battery module 100 is formed between 520 and 530.
[57]
When the potential difference formed between the pair of metal layers 520 and 530 in this way reaches a large value outside the safety range considering the specifications of the battery module 100 due to issues such as overcharging, the polymer forming the EAP layer 510 The mobile cation present in the electrolyte moves toward the negatively charged first metal layer 520 while hydrated in water. In this case, osmotic pressure is caused due to an imbalance in the ion concentration between the first metal layer 520 and the second metal layer 530, and the amount of water molecules toward the negatively charged first metal layer 520 increases. As a result, bending deformation in a direction toward the second metal layer 530 occurs in the current blocking member 500.
[58]
In order to change the shape of the current blocking member 500 and the operation of the switch 400 accordingly, the first metal layer 520 faces the switch 400 and is connected to the negative electrode of the battery module 100. 2 The metal layer 530 is connected to the positive electrode of the battery module 100 on the contrary.
[59]
In addition, both ends of the connection rod 600 are fixed to the first metal layer 520 and the switch 400, respectively, and are made of a non-conductive material. This is because if the connection rod 600 has conductivity, the first metal layer 520 is connected to both the positive electrode and the negative electrode of the battery module 100 so that the current blocking member 500 cannot be bent or deformed. .
[60]
On the other hand, the magnitude of the voltage that can cause shape deformation of the current blocking member 500 varies depending on the type of polymer electrolyte constituting the EAP layer 510 applied to the current blocking member 500.
[61]
That is, the reference value of the voltage referred to in the present specification may vary depending on the type of the polymer electrolyte to be applied, and accordingly, each battery module 100 constituting the battery pack to which the current blocking member 500 is applied has By selecting an appropriate polymer electrolyte according to the safe voltage range, it is possible to quickly cut off current when an event such as overcharging of the battery pack occurs.
[62]
Next, a modified example of the connection structure between the current blocking member and the switch shown in FIG. 1 will be described with reference to FIG. 6.
[63]
6 is a view showing a modified example of the connection structure between the current blocking member and the connecting plate shown in FIG. 1.
[64]
Referring to FIG. 6, both ends of the connection rod 600 may be hinged to the upper surface of the switch 400 and the first metal layer 520, respectively. In this way, when the connecting rod 600 is hinged with the switch 400 and the current blocking member 500, the switch 400, the current blocking member 500, and the connecting rod 600 can be rotated relative to each other. It is done. Therefore, when the free end of the current blocking member 500 moves upward due to the bending deformation of the current blocking member 500, the free end of the switch 300 is also It will be able to move smoothly upwards.
[65]
As described above, in the battery pack according to the present invention, the on/off operation of the switch 400 that electrically connects the adjacent battery modules 100 to each other is applied to the voltage of the battery module 100. Accordingly, it is configured to be performed using the current blocking member 500 that causes bending deformation, thereby ensuring safety in use of the battery pack.
[66]
On the other hand, the vehicle according to the embodiment of the present invention shown in FIG. 7 of the present invention is implemented in a form including the battery pack according to the present invention as described above.
[67]
Although the present invention in the above has been described by the limited embodiments and drawings, the present invention is not limited thereto, and the technical idea of ​​the present invention and the following will be described by those of ordinary skill in the art. It goes without saying that various modifications and variations are possible within the scope of the claims.
Claims
[Claim 1]
A battery module assembly including a first battery module and a second battery module; A first connector connected to a first electrode of the first battery module; A second connector connected to a second electrode of the second battery module and disposed to be spaced apart from the first connector; A switch connecting the first connector and the second connector; A current blocking member connected to one side of the switch in the longitudinal direction and causing a bending deformation to turn off the switch when a potential difference formed between both ends of the battery module is greater than or equal to a reference value; Battery pack comprising a.
[Claim 2]
The battery pack of claim 1, wherein the battery module includes a plurality of battery cells electrically connected to each other.
[Claim 3]
The switch of claim 1, wherein one side of the switch in the length direction is in contact with the first connector, but is formed at a free end so that the contact state with the first connector is released by bending deformation of the current blocking member, and the switch The other side in the longitudinal direction of the battery pack, characterized in that formed with a fixed end fixed to the second connector.
[Claim 4]
The method of claim 1, wherein one side in the length direction of the current blocking member is a free end whose position can be changed by the bending deformation, and the other side of the current blocking member is directly or indirectly fixed to the battery module or the ground. Battery pack, characterized in that the fixed end.
[Claim 5]
According to claim 1, The current blocking member, 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. Battery pack comprising a.
[Claim 6]
The battery pack according to claim 5, wherein the EAP layer comprises at least one polymer electrolyte selected from Nafion, polypyrrole, polyaniline, and polythiophene.
[Claim 7]
The battery pack according to claim 5, wherein the first metal layer and the second metal layer include any one metal selected from the group containing platinum, silver, and copper.
[Claim 8]
The battery pack of claim 5, wherein the first metal layer is electrically connected to a negative electrode of the battery module, and the second metal layer is electrically connected to a positive electrode of the battery module.
[Claim 9]
The battery pack of claim 8, wherein the current blocking member is positioned above the switch, and the first metal layer faces the switch.
[Claim 10]
The battery pack of claim 5, wherein the battery pack further comprises a non-conductive connection rod connecting the switch and the first metal layer.
[Claim 11]
The battery pack of claim 10, wherein the connection rod is hingedly coupled to the switch and the first metal layer, respectively.
[Claim 12]
A vehicle comprising the battery pack according to any one of claims 1 to 11