Title of Invention: Battery module and battery pack including same
technical field
[One]
Cross-Citation with Related Application(s)
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0103781 dated August 23, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[3]
The present invention relates to a battery module and a battery pack including the same, and more particularly, to a battery module with improved safety against abnormal operating conditions and a battery pack including the same.
background
[4]
Secondary batteries that are easy to apply according to product groups and have electrical characteristics such as high energy density are universally applied to electric vehicles or hybrid vehicles driven by an electric drive source, as well as portable devices, and power storage devices. These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency in that not only the primary advantage of being able to dramatically reduce the use of fossil fuels but also the fact that no by-products are generated from the use of energy.
[5]
In the case of secondary batteries used in small devices, 2-3 battery cells are disposed, but in the case of secondary batteries used in mid- to large-sized devices such as automobiles, a battery module in which a plurality of battery cells are electrically connected this is used In such a battery module, a plurality of battery cells are connected in series or parallel to each other to form a battery cell stack, thereby improving capacity and output. In addition, one or more battery modules may be mounted together with various control and protection systems such as a battery management system (BMS) and a cooling system to form a battery pack.
[6]
At this time, in the battery module, when a plurality of battery cells are connected in series or parallel to each other to form a battery cell stack, a bus bar may be used for electrical connection between the battery cells. The electrode lead protruding from each battery cell was bonded to the bus bar, so that such electrical connection was possible.
[7]
Furthermore, since the bus bar of one battery module and the bus bar of the other battery module were electrically connected through the connecting member, connection between the battery modules was also possible.
[8]
1 is a perspective view illustrating a bus bar 30 and electrode leads 15a and 15b of a conventional battery module, and only necessary components are shown for convenience of description.
[9]
Referring to FIG. 1 , the protruding electrode leads 15a and 15b protruding in the X-axis direction from the battery cell (not shown) may be bent to face the opposite direction to the Y-axis and joined to the bus bar 30 . . In particular, a slit 35 may be formed in the bus bar 30 , and some electrode leads 15b may pass through the slit 35 and be bent to be bonded to the bus bar 30 . The other electrode lead 15a may pass through one side of the bus bar 30 instead of the slit 35 .
[10]
In addition, the bus bar 30 may include a connecting portion 36 extending upward, and a connecting member (not shown) may be connected to the connecting portion 36 . The connection member is connected to a bus bar (not shown) of another battery module, so that electrical connection between the battery modules can be made through the connection member. That is, not only the electrical connection between the battery cells but also the electrical connection between the battery modules may be made by the bus bar 30 .
[11]
On the other hand, when a secondary battery is exposed to high temperature or a large current flows within a short time due to overcharging, external short circuit, needle penetration, local damage, etc., there is a risk of explosion as the battery is heated by IR heat. That is, when the pressure or temperature of the battery increases, the decomposition reaction of the active material and a number of side reactions proceed, and accordingly, the temperature of the battery rises rapidly, which in turn accelerates the reaction between the electrolyte and the electrode. Eventually, a thermal runaway phenomenon occurs in which the temperature of the battery rapidly rises, and when the temperature rises above a certain level, the battery may ignite, and the secondary battery explodes due to the increased internal pressure of the battery.
[12]
Accordingly, a current interruptive device (CID) for blocking current when the secondary battery is placed in an abnormal operating state such as an overcurrent state or a high temperature state may be provided.
[13]
However, there are several problems as follows in applying the current blocking member (CID) to a medium-to-large battery pack including a plurality of battery modules.
[14]
In the case of a current blocking member (CID) used in a conventional small battery, when the internal pressure of the battery cell rises, a specific part is disconnected and safety is secured through the principle of blocking the current. There is a problem that this becomes too large.
[15]
In addition, in the case of a current blocking member (CID) applied to a prismatic battery cell of a medium or large battery pack, when the internal pressure of the battery cell rises, a method of forcibly generating an external short circuit and melting the electrode lead of the battery cell to cut off the current is used. However, this has a problem in that it operates even when the internal pressure of the cell increases during the EOL (End of life) section.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[16]
Embodiments of the present invention are proposed to solve the above problems of the previously proposed methods, and include a battery module capable of effectively blocking current in an abnormal operating state without increasing resistance in a normal operating state, and the same An object of the present invention is to provide a battery pack.
[17]
However, the problems to be solved by the embodiments of the present invention are not limited to the above-described problems and may be variously expanded within the scope of the technical idea included in the present invention.
means of solving the problem
[18]
A battery module according to an embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked; a first bus bar connected to an electrode lead extending from the battery cells; and a connection member connected to the first bus bar for connection with another adjacent battery module, wherein the first bus bar includes a first part connected to the electrode lead and a second part connected to the connection member, wherein A protrusion is formed in one of the first part and the second part, a through hole into which the protrusion is inserted is formed in the other, and the protrusion is inserted into the through hole so that the first part and the second part are formed connected, and the protrusion includes a material that shrinks in volume or changes shape when the temperature rises.
[19]
The protrusion may include a shape memory alloy whose volume shrinks as the temperature rises.
[20]
The protrusion may include a shape memory alloy whose shape changes according to an increase in temperature.
[21]
The shape of the protrusion may change as the temperature rises, so that a width in a direction parallel to the second portion may decrease and a height in a direction perpendicular to the second portion may increase.
[22]
The inner wall of the through hole and the protrusion may be in close contact with each other.
[23]
The protrusion may be inserted into the through hole to form a clinching coupling.
[24]
The second part may include a connection part joined to the connection member.
[25]
The protrusion may have a shape corresponding to the through hole.
[26]
Each of the protrusion and the through hole may be two or more.
[27]
A slit may be formed in the first portion, and the electrode lead may be bent after passing through the slit to be connected to the first portion.
[28]
A bus bar frame may be positioned between the first bus bar and the battery cell stack, and the first bus bar may be mounted to the bus bar frame.
Effects of the Invention
[29]
According to embodiments of the present invention, the bus bar bonded to the connecting member may have a fastening structure between the protrusion and the through hole, and this bus bar does not increase resistance in a normal operating state, but effectively blocks current in an abnormal operating state. can
Brief description of the drawing
[30]
1 is a perspective view showing a bus bar and an electrode lead of a conventional battery module.
[31]
2 is an exploded perspective view of a battery module according to an embodiment of the present invention.
[32]
3 is an exploded perspective view of a first bus bar included in the battery module of FIG. 2 .
[33]
4 is a perspective view illustrating a state in which a first part and a second part of the first bus bar of FIG. 3 are fastened to each other.
[34]
5 is a cross-sectional view taken along the cutting line A-A' of FIG. 4 .
[35]
6 is a cross-sectional view of a first bus bar having a protrusion whose volume shrinks according to an increase in temperature in an abnormal operating state.
[36]
7 is a cross-sectional view of a first bus bar having a protrusion whose shape changes according to an increase in temperature in an abnormal operating state.
Modes for carrying out the invention
[37]
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.
[38]
In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar elements throughout the specification.
[39]
In addition, since the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of description, the present invention is not necessarily limited to the illustrated bar. In order to clearly express various layers and regions in the drawings, the thicknesses are enlarged. And in the drawings, for convenience of description, the thickness of some layers and regions is exaggerated.
[40]
Also, when a part of a layer, film, region, plate, etc. is said to be “on” or “on” another part, this includes not only cases where it is “directly on” another part, but also cases where another part is in between. . Conversely, when we say that a part is "just above" another part, we mean that there is no other part in the middle. In addition, to be "on" or "on" the reference part means to be located above or below the reference part, and to necessarily mean to be located "on" or "on" in the direction opposite to gravity not.
[41]
In addition, throughout the specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.
[42]
In addition, throughout the specification, when referring to "planar", it means when the target part is viewed from above, and "in cross-section" means when viewed from the side when a cross-section of the target part is vertically cut.
[43]
2 is an exploded perspective view of the battery module 100 according to an embodiment of the present invention.
[44]
Referring to FIG. 2 , the battery module 100 according to this embodiment includes a battery cell stack 120 in which a plurality of battery cells 110 are stacked, an electrode lead 150 extending from the battery cells 110 , and It includes the connected bus bars 300 and 400 and the bus bar frame 210 on which the bus bars 300 and 400 are mounted.
[45]
The bus bar frame 210 includes lead slots, the lead slots are aligned to correspond to slots formed in the bus bars 300 and 400 , and the electrode leads 150 are electrically connected to the bus bars 300 and 400 . can Specifically, the electrode lead 150 may be bent after passing through the lead slot and the slots of the bus bars 300 and 400 to be connected to the bus bars 300 and 400 .
[46]
The battery cell 110 is a secondary battery and may be configured as a pouch-type secondary battery. The battery cells 110 may be configured in plurality, and the plurality of battery cells 110 may be stacked to each other so as to be electrically connected to each other to form the battery cell stack 120 .
[47]
Meanwhile, the bus bars 300 and 400 according to the present embodiment may be made of a metal material.
[48]
Among the bus bars 300 and 400 , the first bus bar 300 is connected to the electrode lead 150 as well as the connecting member 500 , and the connecting member 500 is connected to the bus bar (not shown) of another battery module. can be connected That is, the battery module 100 of the present embodiment includes a connection member 500 for connecting the battery module and the battery module.
[49]
Since the first bus bar 300 is connected to the connection member 500 , it serves to electrically connect the battery cells 110 as well as electrically connect the battery modules.
[50]
3 is an exploded perspective view of the first bus bar 300 included in the battery module 100 of FIG. 2 .
[51]
Referring to FIG. 3 together with FIG. 2 , the first bus bar 300 includes a first portion 310 connected to the electrode lead 150 and a second portion 320 connected to the connecting member 500 . .
[52]
A slit 350 may be formed in the first portion 310 to allow the electrode lead 150 to pass therethrough. As mentioned above, the electrode lead 150 may pass through the lead slot and the slit 350 of the bus bar frame 210 together and then be bent to be connected to the first part 310 .
[53]
The connection between the first part 310 and the electrode lead 150 is not particularly limited as long as an electrical connection is possible, but may be welded to each other.
[54]
The second part 320 may include a connection part 360 that is joined to the connection member 500, and the connection part 360 has a bent structure as shown in FIG. 3 for easy bonding with the connection member 500. can be formed
[55]
In addition, a module connection terminal 361 may be formed in the connection part 360 . The module connection terminal 361 is configured to serve as a kind of nut, and serves to connect between adjacent battery modules. In a state in which the connecting member 500 and the connecting part 360 are in contact, the bolt is fastened to the module connecting terminal 361 , so that the connecting member 500 and the connecting part 360 may be physically and electrically connected. Although only one module connection terminal 361 is illustrated, it goes without saying that one or more module connection terminals 361 may be formed as needed.
[56]
In addition, in the connection member 500, it is more preferable that the region except for the portion where the bolt and the nut are fastened as described above is electrically insulated from the outside by being coated with an insulating coating or covered with an insulator.
[57]
Meanwhile, the second bus bar 400 of FIG. 2 does not have such a connection part 360 , and may only serve to electrically connect the electrode leads 150 extending from the battery cells 110 .
[58]
Although the connection member 500 in FIG. 2 is shown in the shape of a plate, if it is connected to the connection part 360 of FIG. 3 to perform an electrical connection between the battery modules, there is no limitation in the form or material of the connection member 500 . That is, the connection member 500 may be in the form of a plate material or a conductor wire, and of course other shapes that enable electrical connection are also possible.
[59]
Meanwhile, a protrusion may be formed in one of the first portion 310 and the second portion 320 , and a through hole may be formed in the other one. 3 illustrates that the through hole 340 is formed in the first portion 310 and the protrusion 330 is formed in the second portion 320 , but this corresponds to one example, and the first portion 310 ), a protrusion may be formed, and a through hole may be formed in the second portion 320 . In addition, although the circular through-hole 340 is illustrated, the shape is not limited as long as it is perforated in the first part 310 or the second part 320 , so a polygonal through-hole is also possible.
[60]
The protrusion 330 may be inserted into the through hole 340 along the X-axis direction to connect the first part 310 and the second part 320 to each other. To this end, the protrusion 330 may be disposed at a position corresponding to the through hole 340 .
[61]
In addition, the protrusion 330 preferably has a shape corresponding to the through hole 340 . For example, as in FIG. 3 , when the through hole 340 formed in the first portion 310 is circular, the protrusion 330 is preferably a cylinder. However, this is an example, and although not illustrated, when a polygonal through hole is formed, the protrusion may be in the form of a polygonal pole corresponding thereto.
[62]
Meanwhile, in order to securely fasten the first part 310 and the second part 320 , the protrusion 330 may be inserted into the through hole 340 to perform a clinching coupling. For this coupling, it is preferable that, among the area of ​​the protrusion 330 , the area of ​​a plane perpendicular to the insertion direction of the protrusion 330 is slightly larger than the area formed by the through hole 340 . In other words, in FIG. 3 , it is preferable that the area of ​​the circle provided by the cylindrical protrusion 330 is slightly larger than the area of ​​the circle formed by the circular through hole 340 .
[63]
Accordingly, when the protrusion 330 is inserted while being fitted into the through hole 340 , the inner wall of the through hole 340 and the protrusion 330 form a structure in close contact with each other, and the first portion 310 in a normal operating state. and the second part 320 may be firmly coupled to each other. This will be described again with reference to FIG. 5 below.
[64]
4 is a perspective view illustrating a state in which the first part 310 and the second part 320 of the first bus bar 300 of FIG. 3 are fastened to each other. That is, in FIG. 3 , the protrusion 330 of the second part 320 is inserted into the through hole 340 of the first part 310 , and the first part 310 and the second part 320 are fastened to each other. is a perspective view showing
[65]
In a normal operating state, as shown in FIG. 4 , the integrated first bus bar 300 is connected to the connecting member to electrically connect the battery modules.
[66]
5 is a cross-sectional view taken along the cutting line A-A' of FIG. 4 . In particular, it is a cross-sectional view in a normal operating state.
[67]
Referring to FIG. 5 , when the protrusion 330 is fitted and inserted into the through hole 340 due to clinching coupling, as mentioned above, the inner wall 341 and the protrusion 330 of the through hole 340 . may form a structure in close contact with each other.
[68]
Through this, the first part 310 and the second part 320 can be securely fastened, and the first bus bar 300 does not affect the resistance in a normal operating state to smoothly transfer the current between the battery modules. can transmit
[69]
In addition, the number of each of the protrusions 330 and the through holes 340 is not limited, but two or more are preferable for firm coupling of the first part 310 and the second part 320 .
[70]
The protrusion 330 includes a material that shrinks in volume or changes shape when the temperature rises. That is, when the battery module is placed in an abnormal operating state such as an overcurrent state or a high temperature state, the temperature of the protrusion 330 increases, and the volume shrinks or the shape changes. Hereinafter, it will be described in detail with reference to FIGS. 6 and 7 .
[71]
6 and 7 are each a cross-sectional view of the first bus bar of FIG. 5 in an abnormal operating state. Specifically, FIG. 6 is a cross-sectional view of the first bus bar 300 having a protrusion 330a that shrinks in volume as the temperature rises, and FIG. 7 includes a protrusion 330b whose shape changes as the temperature rises. It is a cross-sectional view of one first bus bar 300 .
[72]
First, referring to FIG. 6 , when an abnormal operating state such as an overcurrent state or a high temperature state occurs, the temperature of the protrusion 330a of the present embodiment increases, and when the temperature is higher than a certain temperature, the volume may be contracted.
[73]
To this end, the protrusion 330a may include a material that shrinks in volume as the temperature rises, and as a material that shrinks in volume, may include a shape memory alloy. In more detail, after the shape memory alloy is welded to the second part 320 , nickel plating may be performed to form the protrusion 330a. In a normal operating state, electrical conductivity is maintained through nickel plating, and in an abnormal operating state, when the temperature rises above a certain temperature, the volume of the shape memory alloy is reduced, so that the volume of the protrusion 330a can be reduced.
[74]
At this time, the temperature at which the volume shrinkage of the shape memory alloy occurs is preferably 100 to 120 degrees Celsius in order to secure safety against an abnormal operating state.
[75]
As shown in FIG. 6 , since the volume of the protrusion 330a is contracted, the protrusion 330a is separated from the inner wall 341 of the through hole 340 , so that the coupling between the protrusion 330a and the through hole 340 . This loosens up. As a result, the coupling force between the first part 310 and the second part 320 may be reduced, so that they may be separated from each other. In this way, by blocking the current flowing into the battery module, it is possible to improve safety against an abnormal operating state.
[76]
Referring to FIG. 7 , the protrusion 330b may include a material whose shape changes when the temperature rises. For example, it may include a shape memory alloy whose shape changes as it exceeds a certain temperature.
[77]
Similarly, after the shape memory alloy is welded to the second part 320 , it may be nickel-plated to form the protrusion 330b. In a normal operating state, electrical conductivity is maintained through nickel plating, and in an abnormal operating state, when the temperature rises above a certain temperature, the shape of the shape memory alloy may change and the shape of the protrusion 330b may change.
[78]
In particular, when the temperature of the protrusion 330b increases due to an abnormal operating state, the width of the protrusion 330b in a direction parallel to the second portion 320 (Y-axis direction) decreases, and the second portion 320 . The height in a direction (X-axis direction) perpendicular to and may be increased.
[79]
When the protrusion 330b has a cylindrical shape, a decrease in the width in a direction parallel to the second part 320 (Y-axis direction) may be a decrease in the diameter of the cylinder, and a direction perpendicular to the second part 320 . An increase in the height of the (X-axis direction) may be an increase in the height of the cylinder.
[80]
As described above, since the width in the direction parallel to the second portion 320 (the Y-axis direction) is reduced, the protrusion 330b is separated from the inner wall 341 of the through hole 340 to be separated from the first portion 310 . the bond with the loosened As a result, the coupling force between the first part 310 and the second part 320 is reduced, so that they are easily separated from each other.
[81]
In addition, since the height in the direction (X-axis direction) perpendicular to the second part 320 increases, the protrusion 330b has the effect of pushing the second part 320 from the first part 310, It may be more advantageous to cut off current.
[82]
At this time, since there is no limitation on the volume of the protrusion 330b, the volume of the protrusion 330b may be decreased, increased, or maintained according to the decrease in width and increase in height as described above.
[83]
On the other hand, the temperature at which the shape change of the shape memory alloy occurs is preferably 100 to 120 degrees Celsius in order to secure safety against an abnormal operating state.
[84]
In addition, the present invention replaces only the battery module in which the fastening of the first part 310 and the second part 320 is separated, as in FIG. 6 or FIG. 7 , rather than replacing the entire battery pack when an abnormal operating state occurs. can be done, it is more efficient
[85]
On the other hand, although not specifically shown, the battery module of the present invention may include a configuration of a module frame and an end plate for accommodating the battery cell stack and the like to protect it from the outside.
[86]
One or more battery modules according to the present embodiment described above may be mounted together with various control and protection systems such as a battery management system (BMS) and a cooling system to form a battery pack.
[87]
The battery module or battery pack may be applied to various devices. Such a device may be applied to a transportation means such as an electric bicycle, an electric vehicle, or a hybrid, but is not limited thereto, and may be applied to various devices capable of using a secondary battery.
[88]
Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the
[89]
Explanation of symbols
[90]
100: battery module
[91]
210: bus bar frame
[92]
300: first bus bar
[93]
310: first part
[94]
320: second part
[95]
330: protrusion
[96]
340: through hole
[97]
360: connection
[98]
400: second bus bar
[99]
500: connection member
[100]
Claims
[Claim 1]
a battery cell stack in which a plurality of battery cells are stacked; a first bus bar connected to an electrode lead extending from the battery cells; and a connection member connected to the first bus bar for connection with another adjacent battery module, wherein the first bus bar includes a first part connected to the electrode lead and a second part connected to the connection member, wherein A protrusion is formed in one of the first part and the second part, a through hole into which the protrusion is inserted is formed in the other, and the protrusion is inserted into the through hole so that the first part and the second part are formed The battery module is connected, and the protrusion includes a material that shrinks in volume or changes shape when the temperature rises.
[Claim 2]
The battery module of claim 1 , wherein the protrusion includes a shape memory alloy that shrinks in volume according to an increase in temperature.
[Claim 3]
The battery module of claim 1 , wherein the protrusion includes a shape memory alloy whose shape changes according to an increase in temperature.
[Claim 4]
The battery module of claim 1 , wherein the protrusion changes shape as the temperature rises, so that a width in a direction parallel to the second part decreases, and a height in a direction perpendicular to the second part increases.
[Claim 5]
The battery module of claim 1, wherein the inner wall of the through hole and the protrusion are in close contact with each other.
[Claim 6]
The battery module of claim 1 , wherein the protrusion is inserted into the through hole to form a clinching coupling.
[Claim 7]
The battery module of claim 1 , wherein the second part includes a connection part joined to the connection member.
[Claim 8]
The battery module of claim 1 , wherein the protrusion has a shape corresponding to the through hole.
[Claim 9]
The battery module of claim 1, wherein each of the protrusion and the through hole is two or more.
[Claim 10]
The battery module of claim 1 , wherein a slit is formed in the first part, and the electrode lead is bent after passing through the slit to be connected to the first part.
[Claim 11]
The battery module of claim 1 , wherein a bus bar frame is positioned between the first bus bar and the battery cell stack, and the first bus bar is mounted to the bus bar frame.
[Claim 12]
A battery pack comprising at least one battery module according to claim 1 .