Title of Invention: Battery module with improved safety, battery pack including such battery module, and vehicle including such battery pack
Technical field
[One]
The present invention relates to a battery module, and more particularly, to a battery module capable of blocking the flow of current when the temperature rises. The present invention also relates to a battery pack including such a battery module and a vehicle including such a battery pack. This application is an application for claiming priority for Korean Patent Application No. 10-2018-0152786 filed on November 30, 2018, and all contents disclosed in the specification and drawings of the application are incorporated herein by reference.
Background
[2]
Currently, commercially available secondary batteries include nickel cadmium batteries, nickel hydride batteries, nickel zinc batteries, and lithium secondary batteries. Among them, lithium secondary batteries are in the spotlight due to the advantages of free charging and discharging, a very low self-discharge rate, and high energy density because memory effects hardly occur compared to nickel-based secondary batteries.
[3]
These lithium secondary batteries mainly use lithium-based oxides and carbon materials 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 coated with a positive electrode active material on a positive electrode current collector and a negative plate coated with a negative electrode active material on a negative electrode current collector are assembled unit cells having a structure disposed with a separator interposed therebetween, and the electrode It includes a case for sealing the assembly together with an electrolyte solution, that is, a battery case. Lithium secondary batteries are classified into a can-type secondary battery in which an electrode assembly is embedded in a metal can and a pouch-type secondary battery in which the electrode assembly is embedded in a pouch of an aluminum laminate sheet according to the shape of a battery case.
[4]
In recent years, secondary batteries are widely used not only in small devices such as portable electronic devices, but also in mid- to large-sized devices such as automobiles and power storage devices (ESS). When used in such a medium-sized device, a large number of secondary batteries are electrically connected to increase capacity and output to form a battery module or a battery pack. In particular, pouch-type secondary batteries are widely used in such medium and large-sized devices due to advantages such as easy stacking and light weight. The pouch-type secondary battery has a structure in which an electrode assembly to which an electrode lead is connected is accommodated together with an electrolyte in a pouch case and sealed. Part of the electrode lead is exposed to the outside of the pouch case, and the exposed electrode lead is electrically connected to a device in which the secondary battery is mounted, or is used to electrically connect the secondary batteries to each other.
[5]
1 shows a part of a battery module manufactured by connecting pouch-type battery cells. For example, it shows a state in which two pouch-type battery cells are connected in series.
[6]
As shown in FIG. 1, the pouch-type battery cells 10 and 10 ′ include two electrode leads 40 and 40 ′ drawn out of the pouch case 30. The electrode leads 40 and 40 ′ are divided into a positive (+) lead and a negative (-) lead according to their electrical polarity, and are electrically connected to the electrode assembly 20 sealed in the pouch case 30. That is, the positive lead is electrically connected to the positive plate of the electrode assembly 20 and the negative lead is electrically connected to the negative plate of the electrode assembly 20.
[7]
There may be various ways in which the battery cells 10 and 10' are connected in the battery module 1, and FIG. 1 shows that the electrode leads 40 and 40' are bent and placed on the bus bar 50 and then laser welded. A method of connecting the electrode lead 40 of the battery cell 10 and the electrode lead 40 ′ of another battery cell 10 ′ adjacent to the battery cell 10 by welding is shown.
[8]
On the other hand, lithium secondary batteries have a risk of explosion when overheated. In particular, it is applied to electric vehicles including electric vehicles (EV), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). Batteries In battery modules or battery packs that are used by connecting battery cells, it is one of the main tasks to secure safety because a very large accident may occur in case of explosion.
[9]
A typical cause of a rapid increase in the temperature of a lithium secondary battery is when a short-circuit current flows. The short-circuit current mainly occurs when a short circuit occurs in an electronic device connected to a secondary battery, and when a short-circuit phenomenon occurs in a lithium secondary battery, a rapid electrochemical reaction occurs at the positive electrode and the negative electrode to generate heat. The heat generated in this way increases the temperature of the battery cell at a rapid rate, eventually causing ignition. In particular, in the case of a battery module or battery pack including a plurality of battery cells, heat generated from one battery cell propagates to the surrounding battery cells, affecting other battery cells, which increases the risk.
[10]
Conventionally, when the temperature inside the secondary battery rises, a PTC device, a fuse, and the like have been proposed as a means to block an electric current to prevent an explosion. However, these have a problem that a separate mounting space is required within the battery module or battery pack.
[11]
It is very important to ensure safety in that an explosion of a battery module or battery pack not only causes damage to electronic devices or automobiles in which it is employed, but also can lead to a user's safety threat and fire. If the secondary battery is overheated, the risk of explosion and/or ignition increases, and rapid combustion or explosion due to overheating may damage human life and property. Therefore, there is a demand for introduction of a means for sufficiently securing safety in use of a secondary battery.
Detailed description of the invention
Technical challenge
[12]
The problem to be solved by the present invention is to provide a battery module with improved safety by blocking a current when a temperature rises, a battery pack including the battery module, and a vehicle including the battery pack.
[13]
Other objects and advantages of the present invention will be described below, and will be understood by examples of the present invention. Further, the objects and advantages of the present invention can be realized by a combination of configurations and configurations shown in the claims.
Means of solving the task
[14]
The battery module according to the present invention for solving the above problems includes: a bus bar having a substantially plate-shaped thickness thinner than a length and a width, and each having a linear groove on a left side and a right side along the length direction; And battery cells respectively located on the left and right sides of the busbar and electrically connected to each other with the busbar in the center by inserting respective electrode leads into the grooves and making physical contact, wherein the grooves are in a thickness direction at a predetermined temperature or higher. By increasing the size, the physical contact between the electrode lead and the bus bar is released, so that the electrical connection between the battery cells is released.
[15]
Preferably, the groove is provided through a configuration in which the shape memory alloy plates are stacked up and down at intervals. Here, the top and bottom indicate the thickness direction.
[16]
Preferably, the electrode lead is inserted into the groove and physically compressed.
[17]
In one embodiment, a plurality of protrusions may be provided on a surface of the shape memory alloy plates facing each other.
[18]
In another embodiment, the electrode lead is inserted into the groove to be physically compressed, and the protrusions may be provided to engage protrusions formed on the upper and lower shape memory alloy plates during physical compression.
[19]
The electrode lead inserted into the groove on the left side of the bus bar and the electrode lead inserted into the groove on the right side may have opposite polarities. In this case, electrode leads of the same polarity from two or more battery cells may be collected and inserted into the groove.
[20]
In another embodiment, two or more grooves are provided on one side, and an electrode lead is fitted in each groove.
[21]
And, the present invention, as a battery pack, at least one battery module according to the present invention; And a pack case for packaging the at least one battery module.
[22]
In addition, the present invention provides a vehicle, comprising at least one battery pack according to the present invention.
Effects of the Invention
[23]
According to the present invention, the battery module is configured by changing the bus bar while leaving the battery cell as it is. When the temperature of the bus bar rises, the physical contact with the electrode leads is released, so that the electrical connection can be released. Accordingly, when the battery module according to the present invention is overheated, current flow through the electrode lead may be blocked, thereby ensuring safety in an abnormal situation.
[24]
According to the present invention, even when the secondary battery protection circuit does not operate, it is possible to block the flow of current so that no more current flows, for example, to prevent charging, thereby increasing the safety of the battery module. As described above, the battery module of the present invention implements a means to automatically block the flow of current when the temperature rises by improving the bus bar, and thus, the effect of securing the safety of the battery module double with the function of preventing overcharging of the secondary battery protection circuit is also achieved. have.
[25]
According to the present invention, it is possible to provide a battery module using a bus bar that can secure safety when configuring an electrical connection path by connecting adjacent battery cells. When an event such as a situation of reaching an abnormal temperature occurs, the electrode lead that was in physical contact with the bus bar is released from the physical contact through the deformation of the bus bar. As a result, electrical connections between adjacent battery cells are also released, and current flow is blocked, so that the safety of the battery module can be secured.
[26]
According to the present invention, safety is ensured by improving the bus bar of the battery module. There is an advantage in that the safety of the battery module can be secured through a relatively simple process change, such as using the bus bar proposed in the present invention instead of the existing bus bar, and using physical compression instead of the existing welding. When the bus bar is made of a shape memory alloy as proposed in the present invention, the temperature restored to the original shape can be set in advance and an appropriate alloy can be used. Each can be appropriately applied. Since the battery cell itself uses the existing manufacturing process as it is, no process changes or adjustments to the mass production process are required.
[27]
As described above, according to the present invention, the current flow is secured in a normal situation and the battery module performance similar to that of the conventional one is expressed, while the current flow is blocked when the temperature rises to a certain temperature or higher due to an abnormal situation, thereby improving the battery module safety. . Accordingly, the safety of the battery module, the battery pack including the battery pack, and the vehicle including the battery pack may be improved.
Brief description of the drawing
[28]
The following drawings appended to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of ​​the present invention together with the detailed description of the present invention, which will be described later. It is limited to and should not be interpreted.
[29]
1 schematically shows a conventional battery module.
[30]
2 schematically shows a battery module according to an embodiment of the present invention.
[31]
3 is a cross-sectional view showing a state of coupling between a bus bar and an electrode lead in FIG. 2.
[32]
4 is a perspective view of a bus bar included in a battery module according to an embodiment of the present invention.
[33]
5 is a cross-sectional view illustrating a state in which a coupling between a bus bar and an electrode lead is released in the battery module of FIG. 2.
[34]
6 is a cross-sectional view showing a state of coupling between a bus bar and an electrode lead in a battery module according to another exemplary embodiment of the present invention.
[35]
7 is a cross-sectional view showing a state of coupling between a bus bar and an electrode lead in a battery module according to another embodiment of the present invention.
[36]
8 is a cross-sectional view illustrating a state of coupling between a bus bar and an electrode lead in a battery module according to another exemplary embodiment.
[37]
9 is a cross-sectional view illustrating a coupling state between a bus bar and an electrode lead in a battery module according to another exemplary embodiment.
[38]
10 is a view for explaining a battery pack according to another embodiment of the present invention.
[39]
11 is a view for explaining a vehicle according to another embodiment of the present invention.
Mode for carrying out the invention
[40]
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 present specification and claims should not be construed as 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.
[41]
Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only 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. In the drawings, the same reference numerals indicate the same elements.
[42]
In the embodiments described below, the secondary battery refers to a lithium secondary battery. Here, the lithium secondary battery collectively refers to a secondary battery in which lithium ions act as operating ions during charging and discharging to cause an electrochemical reaction in the positive electrode plate and the negative electrode plate.
[43]
On the other hand, even if the name of the secondary battery is changed depending on the type of electrolyte or separator used in the lithium secondary battery, the type of the battery case used to package the secondary battery, the internal or external structure of the lithium secondary battery, etc. Any secondary battery used as should be interpreted as being included in the category of the lithium secondary battery.
[44]
The present invention can also be applied to secondary batteries other than lithium secondary batteries. Therefore, even if the operating ions are not lithium ions, any secondary battery to which the technical idea of ​​the present invention can be applied should be interpreted as being included in the scope of the present invention regardless of the type.
[45]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 2 to 5 of the accompanying drawings.
[46]
2 is a schematic diagram of a battery module according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view showing a state of coupling between a bus bar and an electrode lead in FIG. 2, and FIG. 4 is a battery according to an embodiment of the present invention. It is a perspective view of the bus bar included in the module. 5 is a cross-sectional view illustrating a state in which a coupling between a bus bar and an electrode lead is released in the battery module of FIG. 2.
[47]
As shown in FIG. 2, the battery module 100 includes battery cells 110 and 110 ′ and a bus bar 180. A larger number of battery cells may be included in the battery module 100, but some of them are illustrated for convenience of illustration. For example, it shows a state in which two pouch-type battery cells 110 and 110' are connected in series. However, this is only exemplary, and the present invention is not limited to this connection method.
[48]
The battery cells 110 and 110 ′ are secondary batteries and include two electrode leads 140 and 140 ′ that are drawn out of the pouch case 130. The electrode leads 140 and 140 ′ are divided into a positive (+) lead and a negative (-) lead according to their electrical polarity, and are electrically connected to the electrode assembly 120 sealed in the pouch case 130. That is, the positive lead is electrically connected to the positive plate of the electrode assembly 120 and the negative lead is electrically connected to the negative plate of the electrode assembly 120.
[49]
As shown in FIG. 3, in the battery module 100, the electrode lead 140 of the battery cell 110 and the electrode lead 140 ′ of another battery cell 110 ′ adjacent thereto are bent, and then the bus bar. (180) Each of the two side grooves 183 is inserted into each of the grooves 183 and pressed if necessary, and the bus bar ( 180).
[50]
With further reference to FIG. 4, the bus bar 180 has a substantially plate shape having a thickness T that is thinner than a length L and a width W. Particularly different from the conventional busbar is that linear grooves 183 are provided on the left side 181 and the right side 182 along the length (L) direction, respectively.
[51]
The bus bar 180 may vary in shape and size as much as possible in order to implement various electrical connection relationships. In addition, rather than being used alone, the bus bar 180 is applied to the battery module manufacturing process as an ICB assembly in which electric conductivity, for example, a metal bus bar is combined on a frame made of a plastic material in consideration of the wiring relationship. The shape of the frame and the shape of the bus bar combined with the frame vary according to the connection relationship between the battery modules. Accordingly, it will be appreciated by those skilled in the art that various modifications of the present invention are possible.
[52]
In this embodiment, as seen through FIGS. 2 and 3, one battery cell 110 is located on the left side 181 of the bus bar 180, and another battery cell 110' is located on the right side 182. This is located. Each of the electrode leads 140 and 140' is inserted into the groove 183 to provide physical and electrical contact between the bus bar 180 and the electrode leads 140 and 140'. By doing this, the battery cells 110 and 110 ′ may be electrically connected to each other with the bus bar 180 in the center. In the electrically connected state, for example, the size of the groove 183 is s1, and the electrode leads 140 and 140 ′ may be in physical contact with each other. The electrode leads 140 and 140 ′ are inserted into the groove 183 of the bus bar 180 to come into contact with the inner surface of the bus bar 180, and connect the bus bar 180 and the electrode leads 140 and 140 ′. When all are made of an electrically conductive material, there is an electrical connection between adjacent battery cells 110 and 110 ′.
[53]
The groove 183 may have a shape corresponding to the inserted electrode leads 140 and 140 ′. In other words, the length corresponding to the width of the electrode leads 140 and 140 ′ so that the ends of the electrode leads 140 and 140 ′ drawn out of the pouch case 130 can be inserted and inserted on a substantially horizontal plane, and the electrode lead 140 , 140') may have a size corresponding to the thickness.
[54]
In an unusual situation, for example, above a certain temperature, the groove 183 increases in size in the thickness (T) direction as shown in FIG. 5 (s2> s1), so that between the electrode leads 140 and 140' and the bus bar 180 Physical contact is released. Accordingly, the electrical connection between the battery cells 110 and 110 ′ is also released.
[55]
That is, the groove 183 maintains contact with the electrode leads 140 and 140' in a general use situation of the battery module 100, and when the temperature rises above a certain temperature due to overcurrent or the like, the size of the groove 183 increases. It has a property of releasing contact with the electrode leads 140 and 140 ′ by causing a shape change in an enlarged manner.
[56]
Preferably, so that the size of the groove 183 can be changed according to the temperature, at least the material around the groove 183 of the bus bar 180 is preferably made of a shape memory alloy that can change shape according to the temperature. Accordingly, the electrode leads 140 and 140 ′ may be contacted or the contact may be released. In particular, in this embodiment, if the grooves 183 are provided through a configuration in which the shape memory alloy plate 184 is stacked up and down at intervals, the shape memory alloy plate 184 is originally stored in a shape above a certain temperature. As it is restored, the size of the groove 183 can be increased. Here, the top and bottom refer to the thickness (T) direction.
[57]
Shape memory alloy refers to an alloy that exhibits shape memory effect. Here, the shape memory effect remembers the shape remembered at high temperature and returns to the original shape immediately when exposed to an environment above a certain temperature, no matter how severely deformed at low temperature is applied. It means the phenomenon. Since the shape memory alloy has a remarkably different crystal arrangement between a phase at a high temperature and a phase at a low temperature, even if the shape is deformed at a low temperature, it returns to its original shape when exposed to an environment above a certain temperature. Such shape memory alloys include nickel-titanium alloys (nitinol), copper-zinc alloys, copper-zinc-aluminum alloys, gold-cadmium alloys, indium-thallium alloys, and the like.
[58]
If the entire bus bar 180 is made of such a shape memory alloy, or in particular, if the shape memory alloy plate 184 is stacked to form a part of the bus bar 180, for example, a shape memory alloy is formed at a high temperature of a certain degree or higher. After manufacturing the bus bar 180 so as to form a groove 183 having a size larger than the thickness of the electrode leads 140 and 140' (for example, s2), the groove 183 is replaced with the electrode leads 140 and 140'. After performing a process of applying deformation at a low temperature to have a size s1 corresponding to the thickness, an electrical connection may be completed by inserting the electrode leads 140 and 140 ′ into the groove 183. Alternatively, after inserting the electrode leads 140 and 140 ′ into the groove 183, physical compression is performed to make the inner surface of the bus bar 180 and the electrode leads 140 and 140 ′ in contact with each other and make physical contact. Physical compaction can be performed using a small compactor. Even a small compactor can apply a pressure of 500kg per 1㎠, so the compaction force is sufficient. Accordingly, the electrical contact state through compression can be maintained through sufficient compression force, and a process such as welding is not necessary because only physical compression is sufficient.
[59]
In this process, the shape of the product is changed by changing various conditions in the process, such as the type of alloy used, the composition of the alloy, the molding temperature of the product, and the temperature or pressure when the product is subjected to deformation. It is possible to determine the degree of and the temperature and pattern at which the deformation occurs.
[60]
Therefore, in manufacturing the bus bar 180, the bus bar 180 is appropriate by determining various conditions in the process in consideration of the temperature that the battery cells 110 and 110 ′ constituting the battery module 100 can withstand. It is possible to perform a current cut-off function at temperature. For example, if the bus bar 180 is manufactured using an alloy that changes in shape by storing the shape at about 200°C, the current blocking function can be performed at about 200°C when the battery module 100 is overheated.
[61]
There may be various ways in which the battery cells 110 and 110 ′ are connected in series with each other in the battery module 100. In FIGS. 2 and 3, the electrode leads 140 and 140 ′ are respectively bent and then the bus bar. A method of connecting the electrode lead 140 of the battery cell 110 and the electrode lead 140 ′ of the other battery cell 110 ′ without welding by inserting into the grooves 183 on both sides of the 180 is described. . In this embodiment, the electrode lead 140 fitted into the groove 183 on the left side 181 of the bus bar 180 and the electrode lead 140' fitted in the groove 183 on the right side 182 have opposite polarities. to be. If the electrode lead 140 fitted in the groove 183 of the left side 181 of the bus bar 180 and the electrode lead 140' fitted in the groove 183 of the right side 182 are of the same polarity, the connection is parallel.
[62]
As described above, in the present invention, the electrode leads 140 and 140 ′ are connected to each other by using the bus bar 180 that can increase the size of the groove 183 between the adjacent battery cells 110 and 110 ′ when the temperature rises. . Accordingly, when the battery module 100 is overheated, current flow is blocked through the deformation of the groove 183 of the bus bar 180. Accordingly, even when the secondary battery protection circuit does not operate, it is possible to block the flow of current so that no more current flows, for example, to prevent charging, thereby increasing the safety of the battery module 100. As described above, since the battery module 100 of the present invention implements a means for automatically blocking the flow of current when the temperature rises by improving the bus bar 180, the battery module 100 is doubled with the function of preventing overcharging of the secondary battery protection circuit. There is also an effect that can secure the safety of ). In addition, the safety of a battery pack including the battery module 100 and a vehicle including the battery pack may be improved.
[63]
If the battery module 100 is manufactured using the bus bar 180 according to the present invention instead of using the conventional bus bar 50 as shown in FIG. 1, it is relatively easy to manufacture the battery module 100 with improved safety. In addition, since there is no change to the battery cells 110 and 110 ′, the existing battery cell manufacturing process can be used as it is. Therefore, it is also an advantage that there is no need for changes to established processes or adjustments to mass production processes.
[64]
6 is a cross-sectional view showing a state of coupling between a bus bar and an electrode lead in a battery module according to another exemplary embodiment of the present invention.
[65]
As in the previous embodiment described with reference to FIGS. 2 to 5, the bus bar 180 is provided with a groove 183 through a configuration in which the shape memory alloy plates 184 are stacked up and down at intervals. . Here, a plurality of protrusions 185 are provided on the surfaces of the shape memory alloy plates 184 facing each other. The shape of the protrusion 185 may be a hemispherical shape, a cone shape, a conical shape, a polygonal column shape, a conical shape, and a polygonal pyramid shape.
[66]
The protrusion 185 may act as a physical contact point or a pressure point above and below the electrode leads 140 and 140 ′. When inserting the electrode leads 140 and 140' into the groove 183 and physically and electrically connecting the busbar 180 and the electrode leads 140 and 140' through physical compression, the protrusion 185 is applied to a narrow area. Since the losing compression force is applied with a greater pressure than when the protrusion 185 is not present, contact and connection between the bus bar 180 and the electrode leads 140 and 140 ′ may be more secure.
[67]
7 is a cross-sectional view showing a state of coupling between a bus bar and an electrode lead in a battery module according to another embodiment of the present invention.
[68]
Similar to the embodiment described with reference to FIG. 6, the bus bar 180 has a shape memory alloy plate 184 stacked up and down at an interval so that a groove 183 is provided, while a shape memory alloy plate (184) A plurality of protrusions 185 are provided on the surfaces facing each other. The protrusions 185 are provided so that the protrusions 185 formed on the upper and lower shape memory alloy plates 184 are engaged with each other during physical compression. That is, the protrusions 185 positioned above the electrode leads 140 and 140' and the protrusions 185 positioned below the electrode leads 140 and 140' are formed at positions that deviate from each other.
[69]
Therefore, even if the electrode leads 140 and 140 ′ are inserted into the groove 183 as shown in FIG. 7A and then the protrusion 185 is compressed only to the extent that physically and electrically connects the electrode leads 140 and 140 ′. As shown in (b), the protrusions 185 formed in the upper and lower shape memory alloy plates 184 may be engaged with each other by performing more pressing. 7(b), the contact area between the electrode leads 140 and 140' and the shape memory alloy plate 184 increases more than that of FIG. 7(a), and even if an external impact is applied, the electrode lead ( 140, 140') and the shape memory alloy plate 184 through the convex contact interface increases the friction force through the increase in the physical contact state is unintentionally released less fear.
[70]
8 is a cross-sectional view illustrating a state of coupling between a bus bar and an electrode lead in a battery module according to another exemplary embodiment.
[71]
Like the embodiment described with reference to FIG. 7, the bus bar 180 has a shape memory alloy plate 184 stacked up and down at an interval to provide a groove 183, while a shape memory alloy plate (184) A plurality of protrusions 185 are provided on the surfaces facing each other.
[72]
Here, the electrode leads 140 of the same polarity are collected from two or more battery cells 110a and 110b, and the electrode leads 140 ′ of the same polarity are collected from the other two or more battery cells 110c and 110d. ) Take an example of inserting into the grooves 183 on both sides. Electrical connections between the plurality of battery cells 110a, 110b, 110c, and 110d in the battery module 100 may be connected in series, parallel, or a combination of series and parallel. When electrode leads of the same polarity are collected, the battery cells are parallel to each other. When the collected electrode leads are connected with the collected electrode leads with different polarities, they are in series. In FIG. 8, the battery cells 110a and 110b on the right side of the bus bar 180 are parallel, the battery cells 110c and 110d on the left side are parallel, and the battery cells 110a and 110b and the battery cells ( Between 110c and 110d) corresponds to the case of series.
[73]
9 is a cross-sectional view illustrating a coupling state between a bus bar and an electrode lead in a battery module according to another exemplary embodiment.
[74]
As in FIG. 8, the electrode lead 140 of two or more battery cells 110a and 110b is on the right side of the bus bar 180, and the electrode lead 140 ′ of the other two or more battery cells 110c and 110d. Is connected to the left side of the bus bar 180. In Fig. 8, an example in which electrode leads of the same polarity are gathered and inserted into one groove 183 is exemplified, but in this embodiment, the grooves 183a, 183b, 183c, 183d are provided as many as the number of electrode leads, and each groove 183a, 183b , 183c, 183d, each of the electrode leads 140 and 140' is fitted and compressed.
[75]
In the above embodiments, for example, the electrical connection between one battery cell 110 and another battery cell 110 ′ is deformed when the battery module 100 reaches a certain temperature such as about 200°C. Through this, the physical contact between the bus bar 180 and the electrode leads 140 and 140 ′ is released. Accordingly, a normal current flow path is formed in a normal current range and accordingly in a normal temperature range, and the current flow path is blocked when an abnormal temperature reaching about 200°C is reached by an overcurrent or the like. Only when the bus bar 180 is overheated, the contact between the bus bar 180 and the electrode leads 140 and 140 ′ is released, so that safety against fire or explosion due to an abnormal temperature can be secured. In addition, there is an advantage in that it does not reduce energy density because it does not take up space in the module like other devices for improving safety, such as PTC devices or fuses.
[76]
According to the present invention, the battery module is configured by changing the bus bar while leaving the battery cell as it is. When the temperature of the bus bar rises, the physical contact with the electrode leads is released, so that the electrical connection can be released. Accordingly, when the battery module according to the present invention is overheated, current flow through the electrode lead may be blocked, thereby ensuring safety in an abnormal situation.
[77]
According to the present invention, even when the secondary battery protection circuit does not operate, it is possible to block the flow of current so that no more current flows, for example, to prevent charging, thereby increasing the safety of the battery module. As described above, the battery module of the present invention implements a means to automatically block the flow of current when the temperature rises by improving the bus bar, and thus, the effect of securing the safety of the battery module double with the function of preventing overcharging of the secondary battery protection circuit is also achieved. have.
[78]
According to the present invention, it is possible to provide a battery module using a bus bar capable of securing safety when configuring an electrical connection path by connecting adjacent battery cells in series. When an event such as a situation of reaching an abnormal temperature occurs, the electrode lead that was in physical contact with the bus bar is released from the physical contact through the deformation of the bus bar. As a result, the battery cells adjacent to each other are disconnected from the electrical connection and the current flow is blocked, so that the safety of the battery module can be secured.
[79]
According to the present invention, safety is ensured by improving the bus bar of the battery module. There is an advantage in that the safety of the battery module can be secured through a relatively simple process change, such as using the bus bar proposed in the present invention instead of the existing bus bar, and using physical compression instead of the existing welding. When the busbar is made of a shape memory alloy, the temperature restored to the original shape can be adjusted, so that the busbar can be manufactured according to the temperature required to block current flow and applied appropriately for each battery module specification. Since the battery cell itself uses the existing manufacturing process as it is, no process changes or adjustments to the mass production process are required.
[80]
As described above, according to the present invention, the current flow is secured under normal circumstances and the battery cell performance similar to that of the existing electrode leads is expressed, while the current flow is blocked when the temperature rises to a certain temperature or higher due to an abnormal situation, thereby improving the battery module safety. I can. Accordingly, the safety of the battery module, the battery pack including the battery pack, and the vehicle including the battery pack may be improved.
[81]
Since the battery module according to the present invention has excellent safety, it is also suitable for use as a power source for medium and large-sized devices that require high temperature stability, long cycle characteristics, and high rate characteristics. Preferred examples of the medium and large-sized devices include a power tool that is driven by an electric motor; Electric vehicles including EVs, HEVs, PHEVs, and the like; Electric two-wheeled vehicles including electric bicycles (E-bikes) and electric scooters (E-scooters); Electric golf cart; And ESS, but are not limited thereto.
[82]
10 is a view for explaining a battery pack according to another embodiment of the present invention. 11 is a view for explaining a vehicle according to another embodiment of the present invention.
[83]
Referring to FIGS. 10 and 11, the battery pack 200 may include at least one battery module according to the previous embodiment, for example, the battery module 100 of the second embodiment and a pack case 210 packaging the same. . In addition, the battery pack 200 according to the present invention includes various devices for controlling the charging and discharging of the battery module 100 in addition to the battery module 100 and the pack case 210, such as BMS (Battery Management System), current A sensor, a fuse, etc. may be further included.
[84]
The battery pack 200 may be provided in the vehicle 300 as a fuel source for the vehicle 300. As an example, the battery pack 200 may be provided in the vehicle 300 in an electric vehicle, a hybrid vehicle, and other ways in which the battery pack 200 can be used as a fuel source.
[85]
Preferably, the vehicle 300 may be an electric vehicle. The battery pack 200 may be used as an electric energy source for driving the vehicle 300 by providing driving power to the motor 310 of the electric vehicle. In this case, the battery pack 200 has a high nominal voltage of 100V or more. For hybrid vehicles, it is set to 270V.
[86]
The battery pack 200 may be charged or discharged by the inverter 320 according to the driving of the motor 310 and/or the internal combustion engine. The battery pack 200 may be charged by a regenerative charging device combined with a break. The battery pack 200 may be electrically connected to the motor 310 of the vehicle 300 through the inverter 320.
[87]
BMS is also included in the battery pack 200. The BMS estimates the states of the battery cells in the battery pack 200 and manages the battery pack 200 using the estimated state information. For example, state information of the battery pack 200 such as SOC (State Of Charge), SOH (State Of Health), maximum input/output power allowance, and output voltage of the battery pack 200 is estimated and managed. In addition, charging or discharging of the battery pack 200 is controlled by using this state information, and further, it is possible to estimate the replacement timing of the battery pack 200.
[88]
The ECU 330 is an electronic control device that controls the state of the vehicle 300. For example, torque information is determined based on information such as an accelerator, a brake, and a speed, and the output of the motor 310 is controlled to match the torque information. In addition, the ECU 330 transmits a control signal to the inverter 320 so that the battery pack 200 can be charged or discharged based on state information such as SOC and SOH of the battery pack 200 received by the BMS. The inverter 320 allows the battery pack 200 to be charged or discharged based on a control signal from the ECU 330. The motor 310 drives the vehicle 300 based on control information (eg, torque information) transmitted from the ECU 330 by using the electric energy of the battery pack 200.
[89]
The vehicle 300 includes the battery pack 200 according to the present invention, and the battery pack 200 includes a battery module 100 with improved safety as described above. Accordingly, the stability of the battery pack 200 is improved, and since the battery pack 200 has excellent stability and can be used for a long time, the vehicle 300 including the battery pack 200 is safe and easy to operate.
[90]
In addition, it goes without saying that the battery pack 200 may be provided in other devices, devices, and facilities, such as an ESS BMS using a secondary battery, in addition to the vehicle 300.
[91]
As such, devices, devices, and facilities including the battery pack 200, such as the battery pack 200 and the vehicle 300 according to the present embodiment, include the above-described battery module 100, the aforementioned battery module. The battery pack 200 having all of the advantages due to the 100 and a device, apparatus, and equipment such as a vehicle 300 including the battery pack 200 may be implemented.
[92]
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 to which the present invention pertains. It goes without saying that various modifications and variations are possible within the scope of the claims.
Claims
[Claim 1]
A substantially plate-shaped bus bar having a thin thickness compared to the length and width, and having linear grooves on the left and right sides along the length direction, respectively; And battery cells respectively located on the left and right sides of the busbar and electrically connected to each other with the busbar in the center by inserting respective electrode leads into the grooves and making physical contact, wherein the grooves are in a thickness direction at a predetermined temperature or higher. A battery module, characterized in that the electrical connection between the battery cells is released by releasing the physical contact between the electrode lead and the bus bar due to an increase in size.
[Claim 2]
The battery module according to claim 1, wherein the groove is provided through a configuration in which the shape memory alloy plates are stacked up and down at intervals.
[Claim 3]
The battery module according to claim 1, wherein the electrode lead is inserted into the groove and physically compressed.
[Claim 4]
The battery module according to claim 2, wherein a plurality of protrusions are provided on the surfaces of the shape memory alloy plates facing each other.
[Claim 5]
The battery module according to claim 4, wherein the electrode leads are inserted into the grooves to be physically compressed, and the protrusions are provided to engage protrusions formed on the upper and lower shape memory alloy plates during physical compression.
[Claim 6]
The battery module of claim 1, wherein polarities of the electrode lead inserted into the groove on the left side of the bus bar and the electrode lead inserted into the groove on the right side are opposite to each other.
[Claim 7]
The battery module according to claim 6, wherein electrode leads of the same polarity from two or more battery cells are collected and inserted into the grooves.
[Claim 8]
The battery module of claim 1, wherein two or more of the grooves are provided on one surface, and an electrode lead is fitted in each groove.
[Claim 9]
At least one battery module according to any one of claims 1 to 8; And a pack case for packaging the at least one battery module.
[Claim 10]
A vehicle comprising at least one battery pack according to claim 9.