[One]Cross-Citation with Related Application(s)
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0034610 dated March 26, 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 bus bar module and a method for manufacturing the same, and more particularly, to a bus bar module with improved connection between an electrode lead and a bus bar and a method for manufacturing the same.
background
[4]
In modern society, as portable devices such as mobile phones, laptops, camcorders, and digital cameras are used daily, the development of technologies related to the mobile devices as described above is being actively developed. In addition, a rechargeable battery capable of charging and discharging is a method to solve air pollution such as conventional gasoline vehicles using fossil fuels, and electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles ( P-HEV) is being used as a power source, and the need for the development of secondary batteries is increasing.
[5]
Currently commercialized secondary batteries include nickel cadmium batteries, nickel hydride batteries, nickel zinc batteries, and lithium secondary batteries. Among them, lithium secondary batteries do not have much memory effect compared to nickel-based secondary batteries, so charging and discharging are possible freely. , the self-discharge rate is very low and the energy density is high.
[6]
These lithium secondary batteries mainly use a lithium-based oxide and a carbon material as a positive electrode active material and a negative electrode active material, respectively. A lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate to which the positive electrode active material and the negative electrode active material are applied, respectively, are disposed with a separator interposed therebetween, and a casing for sealing and housing the electrode assembly together with an electrolyte, that is, a battery case.
[7]
In general, a lithium secondary battery may be classified into a prismatic secondary battery in which an electrode assembly is embedded in a metal can, and a pouch-type secondary battery in which an electrode assembly is embedded in a pouch of an aluminum laminate sheet, depending on the shape of the exterior material.
[8]
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 devices such as automobiles, a battery pack in which a plurality of battery cells are electrically connected is used.
[9]
Such a battery pack usually includes a plurality of secondary batteries, and the plurality of secondary batteries are connected in series and parallel to each other to improve capacity and output. In this case, the battery pack may include a busbar module for electrical connection between a plurality of secondary batteries, ie, battery cells. The bus bar module includes an electrode lead connected to each battery cell and a bus bar for connecting the electrode lead, and may be formed on one side of a battery module in which a plurality of battery cells are stacked. .
[10]
FIG. 1 is a plan view showing a conventional bus bar module, and FIG. 2 is a cross-sectional view AA′ of the bus bar module of FIG. 1 . For convenience of explanation, only the necessary components are shown.
[11]
1 and 2 , in the case of a conventional bus bar module, electrode leads 40 respectively connected to a plurality of battery cells (not shown) are electrically connected to each other through the bus bar 10 . To this end, the electrode lead 40 and the bus bar 10 are welded, and more specifically, the electrode lead 40 is bent and then welded to the upper surface of the bus bar 10 . Ultrasonic welding, laser welding, or resistance welding may be used for such welding.
[12]
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.
[13]
Accordingly, when the secondary battery is placed in an abnormal operating state such as an overcurrent state or a high temperature state, a current interruptive device (CID) for interrupting current may be provided.
[14]
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 cells.
[15]
In the case of a current blocking member (CID) used in a conventional small battery, when the internal pressure of the battery cell increases, 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.
[16]
In addition, in the case of a current blocking member (CID) applied to a prismatic battery cell of a mid- to large-sized 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
[17]
The problem to be solved by the embodiments of the present invention is to solve the above problems, and a bus bar module capable of effectively blocking current in an abnormal operating state without increasing resistance in a normal operating state, and a method for manufacturing the same is to provide
means of solving the problem
[18]
A bus bar module according to an embodiment of the present invention includes: a bus bar including an upper plate and a lower plate overlapping the upper plate; an electrode lead positioned between the upper plate and the lower plate; and a connecting part disposed between the upper plate and the electrode lead to electrically connect the upper plate and the electrode lead, a through hole being formed in the lower plate, and the connecting part being disposed at a position corresponding to the through hole.
[19]
The connection part may include a material whose volume shrinks when the temperature rises.
[20]
The connection part may include a shape memory alloy whose volume shrinks according to an increase in temperature.
[21]
The shape of the connection part may change according to an increase in temperature.
[22]
The connection part may include a shape memory alloy whose shape changes according to an increase in temperature.
[23]
The connection part may face the lower plate from the upper plate, and the electrode lead may include a protrusion protruding into the through hole.
[24]
The electrode lead surrounds the connection part and may be inserted into the through hole.
[25]
Inside the through hole, the electrode lead may be in close contact with each of the connection part and the lower plate.
[26]
The connection part may have a shape corresponding to the through hole.
[27]
Each of the connection part and the through hole may be two or more.
[28]
A method of manufacturing a bus bar module according to an embodiment of the present invention includes: positioning an electrode lead between an upper plate having a protruding connection part and a lower plate having a through hole; and fastening the upper plate and the lower plate with the electrode lead interposed therebetween, wherein in the fastening step, the connection part is inserted into the through hole together with the electrode lead.
[29]
The shape of the connection part may change according to an increase in temperature.
[30]
The connection part may include a shape memory alloy whose shape changes according to an increase in temperature.
[31]
The upper plate and the lower plate may be coupled through clinching bonding.
Effects of the Invention
[32]
According to embodiments of the present invention, the bus bar and the electrode lead may be coupled through the coupling structure of the connection part and the through hole, and the resistance may not be increased in a normal operating state, but current may be effectively blocked in an abnormal operating state.
Brief description of the drawing
[33]
1 is a plan view of a conventional bus bar module.
[34]
FIG. 2 is a cross-sectional view taken along AA′ of the bus bar module of FIG. 1 .
[35]
3 is an exploded perspective view of a battery module according to an embodiment of the present invention.
[36]
FIG. 4 is a plan view of the bus bar module of FIG. 3 .
[37]
FIG. 5 is a cross-sectional view in the BB′ direction of the bus bar module of FIG. 4 .
[38]
FIG. 6 is a sectional view in the CC′ direction of the bus bar module of FIG. 4 .
[39]
7 is a perspective view of the bus bar of FIG. 4 before it is fastened;
[40]
8 is a cross-sectional view of the bus bar module of FIG. 6 in an abnormal operating state.
[41]
9 is a cross-sectional view of a bus bar module in an abnormal operating state according to another embodiment of the present invention.
[42]
10 is a cross-sectional view for explaining a method of manufacturing a bus bar module according to an embodiment of the present invention.
Modes for carrying out the invention
[43]
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.
[44]
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.
[45]
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.
[46]
Further, when a part of a layer, film, region, plate, etc. is said to be “on” or “on” another part, it 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 the gravitational force no.
[47]
In addition, throughout the specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.
[48]
3 is an exploded perspective view of a battery module according to an embodiment of the present invention.
[49]
Referring to FIG. 3 , the battery module 1000 according to the present embodiment includes a plurality of battery cells 300 and a bus bar module 100 positioned on both sides of the plurality of battery cells 300 . The battery module 1000 may further include a top cover 400 covering the plurality of battery cells 300 .
[50]
The bus bar module 100 includes an electrode lead 140 connected to a plurality of battery cells 300 , a bus bar 110 connected to the electrode lead 140 , and a bus bar frame 200 on which the bus bar 110 is mounted. may include A slit is formed in the bus bar frame 200 so that the electrode lead 140 may pass through the slit to be connected to the bus bar 110 .
[51]
FIG. 4 is a plan view of the bus bar module 100 of FIG. 3 , and for convenience of explanation, only the bus bar 110 and the electrode lead 140 are shown, and the rest of the configuration is not shown.
[52]
FIG. 5 is a cross-sectional view in the BB′ direction of the bus bar module of FIG. 4 , and FIG. 6 is a cross-sectional view in the CC′ direction of the bus bar module of FIG. 4 .
[53]
4 to 6 , the bus bar module 100 according to an embodiment of the present invention includes a bus bar 110 including an upper plate 120 and a lower plate 130 overlapping the upper plate 120 , The electrode lead 140 positioned between the upper plate 120 and the lower plate 130 and the connection part disposed between the upper plate 120 and the electrode lead 140 to electrically connect the upper plate 120 and the electrode lead 140 ( 121). Although not shown, the electrode lead 140 is connected to a plurality of battery cells.
[54]
A through hole 131 is formed in the lower plate 130 , and the connection part 121 is disposed at a position corresponding to the through hole 131 .
[55]
Meanwhile, in FIGS. 5 and 6 , the electrode lead 140 engaged between the upper plate 120 and the lower plate 130 is illustrated as one, but two or more electrode leads 140 are bent in the same direction, and the upper plate ( It is also possible to overlap each other between the 120 and the lower plate (130).
[56]
7 is a perspective view before the bus bar 110 of FIG. 4 is fastened, and electrode leads are not shown for convenience of explanation. As mentioned above, a through hole 131 is formed in the lower plate 130 of the bus bar 110 . However, although the circular through-hole 131 is illustrated, the shape is not limited as long as it is perforated in the lower plate 130 , so a polygonal through-hole is also possible.
[57]
Referring back to FIGS. 4 to 6 , the connection part 121 faces the lower plate 130 from the upper plate 120 and may be inserted into the through hole 131 together with the electrode lead 140 , and the electrode lead 140 . may form a structure surrounding the connection part 121 inside the through hole 131 .
[58]
Therefore, unlike the conventional bus bar module, the bus bar 110 is mechanically fastened without welding the upper plate 120 , the lower plate 130 , and the electrode lead 140 located between the upper plate 120 and the lower plate 130 . and the electrode lead 140 may be electrically connected to each other. That is, the electrode lead 140 includes the protrusion 141 formed by the pressing of the connection part 121 , and the protrusion 141 forms a structure protruding into the through hole 131 .
[59]
Also, inside the through hole 131 , the electrode lead 140 may be in close contact with the connection portion 121 of the upper plate 120 and the lower plate 130 , respectively. That is, since the contact area between the bus bar 110 and the electrode lead 140 may be increased compared to the conventional welding bonding, the contact resistance between the bus bar 110 and the electrode lead 140 may be reduced.
[60]
On the other hand, in order for the connection part 121 to be inserted into the through hole 131 and to be in close contact with the electrode lead 140 inside the through hole 131 , it is necessary that the connection part 121 has a shape corresponding to the through hole 131 . desirable. For example, as in FIG. 7 , when the circular through hole 131 is formed in the lower plate 130 , the connecting part 121 is preferably a cylinder. In addition, although not shown, when the polygonal through hole is formed, it is preferable that the connecting portion has a shape of a polygonal pole corresponding thereto.
[61]
In addition, although there is no limitation on the number of each of the connection part 121 and the through hole 131 , it is preferable that there are two or more in order to firmly fasten the bus bar 110 and the electrode lead 140 .
[62]
8 is a cross-sectional view of the bus bar module of FIG. 6 in an abnormal operating state.
[63]
Referring to FIG. 8 , when an abnormal operating state such as an overcurrent state or a high temperature state occurs, the temperature of the connection part 121 of the present embodiment rises, and when the temperature is higher than a certain temperature, the volume may be contracted.
[64]
The connection part 121 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, the shape memory alloy may be welded to the upper plate 120 and then nickel-plated to configure the connection part 121 . 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 may decrease, so that the volume of the connection part 121 may be reduced.
[65]
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.
[66]
As shown in FIG. 8 , since the volume of the connection part 121 is contracted, the coupling of the connection part 121 with the electrode lead 140 is loosened, and eventually the coupling force between the upper plate 120 and the electrode lead 140 is decreased. As a result, the upper plate 120 and the electrode lead 140 may be separated from each other. In this way, by blocking the current flowing into the battery cell, it is possible to improve safety against an abnormal operating state.
[67]
9 is a cross-sectional view of a bus bar module in an abnormal operating state according to another embodiment of the present invention.
[68]
Referring to FIG. 9 , a bus bar 210 including an upper plate 220 and a lower plate 230 , and an electrode lead 240 including a through hole 231 and a protrusion 241 formed in the lower plate 230 are shown in FIG. Since the same or similar configuration to the bus bar module of FIG. 8 is applied, a description thereof will be omitted.
[69]
However, the connection part 221 connected to the upper plate 220 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.
[70]
In particular, when the temperature of the connection part 221 increases due to an abnormal operating state, the width of the connection part 221 in a direction parallel to the top plate 220 (X direction) decreases, and in a direction perpendicular to the top plate 220 ( Y direction) may increase in height. When the connecting portion 221 is a cylinder, a decrease in the width in a direction parallel to the upper plate 220 (X direction) may be a decrease in the diameter of the cylinder, and a height in a direction (Y direction) perpendicular to the upper plate 220 . An increase in may be an increase in the height of the cylinder.
[71]
As described above, since the width in the direction (X direction) parallel to the upper plate 220 is reduced, the connection part 221 with the electrode lead 240 is loosened, and eventually the upper plate 220 and the electrode lead 140 . The coupling force therebetween is reduced, so that the upper plate 220 and the electrode lead 240 are easily separated from each other. In addition, since the height in the direction (Y direction) perpendicular to the upper plate 220 increases, the connection part 221 has the effect of pushing the upper plate 220 from the electrode lead 240 and the lower plate 230 , Blocking may be more beneficial.
[72]
At this time, since there is no limitation on the volume of the connection part 221 , the volume of the connection part 221 may be decreased, increased, or maintained according to the decrease in width and increase in height as described above.
[73]
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.
[74]
10 is a cross-sectional view for explaining a method of manufacturing a bus bar module according to an embodiment of the present invention.
[75]
Referring to FIG. 10 , in the method of manufacturing a bus bar module according to an embodiment of the present invention, the electrode lead 140 is formed between the upper plate 120 on which the protruding connection part 121 is formed and the lower plate on which the through hole 131 is formed. a step of positioning and fastening the upper plate 120 and the lower plate 130 with the electrode lead 140 interposed therebetween. (131) is inserted into the interior.
[76]
Unlike conventional laser welding or ultrasonic welding, the bus bar 110 and the electrode lead 140 are coupled through clinching bonding. That is, with the electrode lead 140 interposed therebetween, the upper plate 120 and the lower plate 130 are compressed using a punch or die of a specified size, and physical deformation occurs to the upper plate 120 . , the lower plate 130 and the electrode lead 140 are fastened.
[77]
On the other hand, the structure and material described above may be applied to the connection part 121 and the through hole 131 , and the description thereof will be omitted because overlapping content.
[78]
The battery module including the bus bar module described above may be applied to various devices. Such a device may be applied to transportation means such as an electric bicycle, an electric vehicle, or a hybrid, but is not limited thereto, and may be applied to various devices that may use a secondary battery.
[79]
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
[80]
[Explanation of code]
[81]
100: bus bar module
[82]
110: bus bar
[83]
120: top plate
[84]
121: connection
[85]
130: lower plate
[86]
131: through hole
[87]
140: electrode lead
[88]
1000: battery module

WE CLAIMS

a bus bar including an upper plate and a lower plate overlapping the upper plate; an electrode lead positioned between the upper plate and the lower plate; and a connector disposed between the upper plate and the electrode lead to electrically connect the upper plate and the electrode lead, wherein a through hole is formed in the lower plate, and the connector is disposed at a position corresponding to the through hole. module.
[Claim 2]
The bus bar module of claim 1 , wherein the connection part includes a material whose volume shrinks when a temperature rises.
[Claim 3]
The bus bar module of claim 2 , wherein the connection part includes a shape memory alloy that shrinks in volume according to an increase in temperature.
[Claim 4]
The bus bar module of claim 1 , wherein the connection part changes in shape according to an increase in temperature.
[Claim 5]
5 . The bus bar module of claim 4 , wherein the connection part includes a shape memory alloy whose shape changes according to an increase in temperature.
[Claim 6]
The bus bar module of claim 1 , wherein the connection part faces the lower plate from the upper plate, and the electrode lead includes a protrusion protruding into the through hole.
[Claim 7]
The bus bar module of claim 1 , wherein the electrode lead surrounds the connection part and is inserted into the through hole.
[Claim 8]
The bus bar module of claim 1 , wherein the electrode lead is in close contact with each of the connection part and the lower plate in the through hole.
[Claim 9]
The bus bar module of claim 1 , wherein the connecting portion has a shape corresponding to the through hole.
[Claim 10]
The bus bar module of claim 1, wherein each of the connection part and the through hole is two or more.
[Claim 11]
A battery module comprising the bus bar module according to claim 1 .
[Claim 12]
positioning an electrode lead between the upper plate on which the protruding connection part is formed and the lower plate on which the through hole is formed; and fastening the upper plate and the lower plate with the electrode lead interposed therebetween, wherein in the fastening step, the connection part is inserted into the through hole together with the electrode lead.
[Claim 13]
The method of claim 12 , wherein the connection part changes in shape according to an increase in temperature.
[Claim 14]
The method of claim 13 , wherein the connection part includes a shape memory alloy whose shape changes according to an increase in temperature.
[Claim 15]
The method of claim 12 , wherein the coupling between the upper plate and the lower plate is performed through clinching bonding.