Battery pack with improved safety

Abstract

The present invention discloses a battery pack that can ensure safety even when high-temperature gas is generated inside due to thermal runaway, etc. The battery pack according to one aspect of the present invention includes a battery module including one or more battery cells and module terminals, a pack case that houses the battery module in an internal space and has pack terminals on at least one side thereof, and a safety bus bar that is connected between the module terminals and the pack terminals or between the module terminals to provide a power path and to block the power path by vent gas discharged from the battery module.

Description

[Technical field]

[0001] This application claims priority to Korean Patent Application No. 10-2021-0113529 filed on August 26, 2021 and Korean Patent Application No. 10-2022-0106420 filed on August 24, 2022, the entire disclosures of which in the specification and drawings are incorporated herein by reference.

[0002] The present invention relates to a battery, and more particularly to a battery pack capable of improving safety in the event of an event such as thermal runaway, and an energy storage system including the same. [Background technology]

[0003] 2. Description of the Related Art In recent years, as the demand for portable electronic products such as smartphones and smart pads has increased dramatically and robots, electric vehicles, and the like have come into full swing for commercialization, active research has been conducted into high-performance secondary batteries that can be repeatedly charged and discharged.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. In particular, lithium secondary batteries have been attracting attention due to the advantages that they can be freely charged and discharged since they hardly have a memory effect compared to nickel-based secondary batteries, and they have a very low self-discharge rate and high energy density.

[0005] Although a secondary battery may be used alone, it is generally configured by connecting a plurality of secondary batteries electrically in series and / or in parallel to each other. In particular, a plurality of secondary batteries may be electrically connected to each other and housed in a module case to configure a single battery module. Furthermore, the battery module may be used alone, or two or more of the battery modules may be electrically connected to each other in series and / or in parallel to configure a higher level device such as a battery pack. Here, the battery module and the battery pack may be used together.

[0006] In recent years, as problems such as power shortages and environmentally friendly energy have become apparent, energy storage systems (ESS) for storing generated electricity have been attracting much attention. Typically, the use of such energy storage systems makes it easy to build power management systems such as smart grid systems, and makes it easy to adjust the supply and demand of electricity in a specific region or city. In addition, as electric vehicles are becoming more and more commercialized, such energy storage systems can also be applied to charging stations (electric charging stations) where electric vehicles can be charged.

[0007] In the case of a battery pack used in such an energy storage system, one or more, particularly a plurality of battery modules, may be accommodated in an internal space of a pack case. The battery pack may be connected to an external component, for example, an external charging / discharging device or another battery pack, via a pack terminal provided on at least one side of the pack case. In this case, a power cable or a copper bus bar may be provided inside the battery pack as a path for connecting between the pack terminal and the module terminal to supply power. In particular, when a plurality of battery modules are included and all of the positive and negative pack terminals are located on the same side, a module terminal of a battery module located far from the portion where the pack terminal is located may be connected to the pack terminal by extending a power cable or the like.

[0008] However, in such a configuration, if a thermal event such as a thermal runaway occurs in a particular battery module, vent gas may be discharged from the battery module. At this time, the vent gas discharged from the battery module may be in a high temperature state, for example, about 950° C. Furthermore, such vent gas may include sparks, molten electrode ejection, flames, etc.

[0009] When the vent gas having high heat is discharged, electrical connection parts such as a power cable in the battery pack may be damaged by the vent gas. Such damage may cause problems such as a short circuit. In particular, in the case of a power cable, the copper wire is covered with an insulator, and the covering layer may melt due to the high-temperature vent gas, exposing the internal copper wire to the outside. In this case, if the copper wire of the power cable comes into contact with the conductor of the battery pack, a short circuit may occur. Furthermore, although the pack case of the battery pack may be made of a conductive metal material such as steel, if the power cable comes into contact with the pack case due to the flow of vent gas, vibration, or the like, a short circuit may occur. In addition, such a short circuit may not only cause failure or damage to the battery pack, but may also cause a fire and lead to a serious accident. Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, the present invention has been made to solve the above problems, and aims to provide a battery pack and an application device including the same that can ensure safety even if high-temperature gas is generated inside due to thermal runaway or the like.

[0011] However, the problems that the present invention aims to solve are not limited to the problems described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention given below. [Means for solving the problem]

[0012] To achieve the above object, a battery pack according to one aspect of the present invention includes a battery module having one or more battery cells and a module terminal; a pack case covering at least a portion of an exterior of the battery module and having a pack terminal provided on at least one side thereof; and a safety bus bar connected between the module terminal and the pack terminal or between the module terminals to provide a power path and to block the power path by vent gas discharged from the battery module.

[0013] Here, the safety bus bar may be disposed in a portion where vent gas is discharged from the battery module.

[0014] The battery pack may further include a plurality of the battery modules stacked in at least one direction, and the safety bus bar may be formed to extend long along the stacking direction of the battery modules.

[0015] Furthermore, the multiple battery modules may be arranged side by side in the left-right direction and configured so that vent gas is discharged forward or backward, and the safety bus bar may be arranged at the front or rear of the stack of multiple battery modules.

[0016] Furthermore, the safety busbar may comprise two or more different metals.

[0017] Furthermore, the safety busbar may be formed by joining the two or more different metals together.

[0018] Furthermore, the safety busbar may be configured such that at least one type of metal among the two or more different types of metals is meltable by the vent gas.

[0019] Furthermore, the safety busbar may include two or more metal layers having different melting points, and the metal layer having a lower melting point may be formed thicker than the metal layer having a higher melting point.

[0020] Furthermore, the safety busbar may be formed of a plurality of high melting point metal layers.

[0021] In order to achieve the above object, an energy storage system according to another aspect of the present invention includes a battery pack according to the present invention.

[0022] Furthermore, in order to achieve the above object, a vehicle according to still another aspect of the present invention includes a battery pack according to the present invention. Effect of the Invention

[0023] According to the present invention, it is possible to provide a battery pack that ensures safety even when vent gas is generated inside due to an event such as thermal runaway.

[0024] In particular, according to one aspect of the present invention, it is possible to more effectively prevent a short circuit caused by damage to a power connection part due to vent gas discharged from a battery module.

[0025] Therefore, according to this aspect of the present invention, it is possible to eliminate risk factors such as secondary fires caused by internal short circuits. [Brief description of the drawings]

[0026] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, are useful for further understanding of the technical concept of the present invention; however, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0027] [Figure 1] 1 is a perspective view showing a schematic configuration of a battery pack according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an exploded perspective view of some of the components of FIG. 1. [Diagram 3] 1 is a perspective view showing one battery module included in a battery pack according to an embodiment of the present invention; [Figure 4] FIG. 4 is a partial perspective view showing some of the components of FIG. 3 separated or removed. [Diagram 5] 1 is a cross-sectional view showing a configuration of a battery pack according to an embodiment of the present invention, viewed from above. [Figure 6] FIG. 6 is an enlarged perspective view of a portion A1 in FIG. 5. [Figure 7] FIG. 7 is a diagram illustrating a schematic configuration in which the safety bus bar is cut by vent gas in the configuration of FIG. 6. [Figure 8] 2 is a diagram illustrating a schematic configuration of a front end portion of a battery pack according to an embodiment of the present invention. FIG. [Figure 9] 1 is a schematic cross-sectional view showing a configuration of a safety bus bar according to an embodiment of the present invention, viewed from above. FIG. [Figure 10] 1 is a cross-sectional view illustrating a schematic configuration of some components of a battery pack according to an embodiment of the present invention. [Figure 11] FIG. 13 is a perspective view illustrating a schematic configuration of some components of a safety busbar according to another embodiment of the present invention. [Figure 12] FIG. 13 is a perspective view illustrating a schematic configuration of some components of a safety bus bar according to still another embodiment of the present invention. [Figure 13] FIG. 11 is a cross-sectional view illustrating a schematic configuration of some components of a safety busbar according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in the specification and claims should not be interpreted in a limited manner based on their ordinary or dictionary meanings, but should be interpreted in a manner that corresponds to the technical concept of the present invention, based on the principle that the inventor himself can appropriately define the concept of the term in order to best describe the invention.

[0029] Therefore, it should be understood that the embodiment described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0030] FIG. 1 is a perspective view that shows a schematic configuration of a battery pack according to one embodiment of the present invention, and FIG. 2 is an exploded perspective view of some of the components in FIG.

[0031] 1 and 2, a battery pack according to the present invention includes a battery module 100, a pack case 200, and a safety bus bar 300.

[0032] The battery module 100 may include one or more battery cells for storing and discharging energy. Here, each battery cell may refer to a secondary battery. Also, one or more battery modules 100 may be included in a battery pack. In particular, in order to improve the capacity and / or output of the battery pack, as shown in FIGS. 1 and 2, a plurality of battery modules 100 may be included in the battery pack. In this case, the plurality of battery modules 100 may be arranged in at least one direction. As an example, FIGS. 1 and 2 show a form in which eight battery modules 100 are arranged in the X-axis direction.

[0033] An example of a more specific configuration of such a battery module 100 is shown in more detail in FIGS.

[0034] Fig. 3 is a perspective view showing one battery module 100 included in a battery pack according to an embodiment of the present invention, and Fig. 4 is a partial perspective view showing some components of Fig. 3 separated or removed.

[0035] 3 and 4, the battery module 100 may include a battery cell 110 (secondary battery).

[0036] Here, the battery cell 110 may include an electrode assembly, an electrolytic solution (electrolyte), and a battery case. Although a pouch-type secondary battery is shown in Fig. 3 and Fig. 4, other types of secondary batteries, such as cylindrical batteries and prismatic batteries, may also be included in the battery module 100.

[0037] A plurality of such secondary batteries may be included. For example, as shown in the figure, a battery assembly may be formed by stacking a plurality of pouch-type secondary batteries in a horizontal position. In this case, the electrode leads 111 of the batteries may be in direct contact with each other or may be electrically connected via a bus bar or the like.

[0038] The battery module 100 may also include a module terminal 140. For example, in the battery module 100, the electrode lead 111 of each battery cell 110 may be located at the front side and / or rear side, and the module terminal 140 may be located in electrical connection with the electrode lead 111. In particular, the module terminal 140 may be located at the front side and / or rear side of the battery module 100 and protrude forward and / or backward. Furthermore, each battery module 100 may include a positive module terminal 140(+) and a negative module terminal 140(-) as the module terminal 140. In this case, the positive module terminal 140(+) and the negative module terminal 140(-) may be located on the same side of the battery module 100, for example, on the front side (-Y axis direction) as shown in the figure. By using such a module terminal 140, the secondary battery (battery cell 110) included in the battery module 100 can be electrically connected to other components outside the battery module 100, for example, other battery modules 100.

[0039] The pack case 200 may be configured to cover at least a part of the outside of the battery module 100. Furthermore, the pack case 200 may be configured to define an internal space and accommodate one or more battery modules 100 in such internal space. That is, the pack case 200 may be configured to surround at least a part of the outside of one or more battery modules 100. For example, as shown in FIG. 1 and FIG. 2, the pack case 200 may include a front case 210, a rear case 220, and a left case 230, and may be configured to cover the front end, the rear end, and the left side of a stack of a plurality of battery modules 100. Furthermore, the pack case 200 may include a right case, an upper case, and / or a lower case, and may be configured to cover the right side, the upper part, and / or the lower part of the stack of battery modules 100.

[0040] In this case, a pack terminal 201 may be provided on at least one side of the pack case 200. Such a pack terminal 201 may function as a terminal capable of transmitting and receiving power to and from an external charging device or discharging device with respect to the battery pack. That is, the pack terminal 201 may be a terminal capable of supplying charging power to each battery module 100 inside the battery pack, or discharging power from each battery module 100 to the outside. Such a pack terminal 201 may include a positive pack terminal 201(+) and a negative pack terminal 201(-). In particular, the positive pack terminal 201(+) and the negative pack terminal 201(-) may be located on the same side of the battery pack. For example, as shown in FIG. 1 and FIG. 2, the positive pack terminal 201(+) and the negative pack terminal 201(-) of the battery pack may be located on the left case 230.

[0041] At least a portion of the pack case 200 may be made of a material such as steel to ensure mechanical rigidity and protect the internal components. Furthermore, at least a portion of the pack case 200 may function as a duct. For example, in the configurations of FIGS. 1 and 2, the front case 210 may function as a duct. In this case, an outlet communicating with the duct may be formed on at least one side of the pack case 200, as shown by H1 in FIG. 1. Therefore, the vent gas discharged to the front case 210 side may flow along the inner surface of the front case 210 and then be discharged to the outside of the pack case 200 through the outlet H1. At this time, not only the vent gas itself may be at a high temperature, but also may contain high-temperature active material particles, flames, and the like. Therefore, the front case 210 may be made of a material such as steel and may be configured to be sufficiently resistant to such high-temperature materials. However, such a pack case 200 may be made of various other materials and shapes. In addition, the pack case 200 may be partially made of different materials.

[0042] The safety bus bar 300 may be included as a component that provides a power path in a battery pack, and one or more safety bus bars 300 may be provided in a battery pack.

[0043] In particular, the safety bus bar 300 may be connected between a module terminal 140 provided in the battery module 100 and a pack terminal 201 provided in the pack case 200. In addition, the safety bus bar 300 may provide an electrical path through which charging power or discharging power can move between the battery module 100 and the pack terminal 201. For example, both ends of the safety bus bar 300 may be connected to a negative module terminal 140(-) of one or more battery modules 100 and a negative pack terminal 201(-) of the pack case 200, respectively.

[0044] Alternatively, when a plurality of battery modules 100 are included inside the pack case 200, the safety bus bar 300 may be connected between module terminals 140 provided on each of the plurality of battery modules 100, so that the battery modules 100 are connected in series and / or in parallel. For example, both ends of the safety bus bar 300 may be connected between the positive module terminals 140(+) of one or more battery modules 100 and the negative module terminals 140(-) of one or more other battery modules 100, respectively.

[0045] The safety busbar 300 may include an electrically conductive material to provide a power path. For example, the safety busbar 300 may be made of an electrically conductive metal material. Also, the safety busbar 300 may include an electrically insulating material to prevent contact with other components. For example, the safety busbar 300 may include an electrically insulating plastic material that covers the outside of the metal material. Furthermore, the safety busbar 300 may be embodied in the form of a flexible busbar having flexibility in which a metal plate is wrapped in a polymer material.

[0046] Particularly, in the battery pack according to the present invention, the safety busbar 300 provides a power path, but may be configured to cut off the power path by vent gas. That is, when vent gas is generated from one or more battery modules 100 included in the battery pack due to thermal runaway or the like, the safety busbar 300 may be configured to cut off the power path by such vent gas. Furthermore, when the battery pack includes a plurality of safety busbars 300, all or some of the safety busbars 300 may be configured to cut off the power path by the vent gas in this manner.

[0047] According to such a configuration of the present invention, it is possible to improve the safety of the battery pack when vent gas is generated from the battery module 100. Furthermore, the situation in which vent gas is generated from the battery module 100 can be said to be an abnormal situation. If the power path of the safety busbar 300 is interrupted in such an abnormal situation, the connection of charging / discharging power to the battery pack may be interrupted. Therefore, it is possible to block or reduce risk factors that may occur due to continued charging or discharging of an abnormal battery pack.

[0048] Meanwhile, the battery pack according to the present invention may further include a pack bus bar of a general form in addition to the safety bus bar 300. For example, when a plurality of battery modules 100 are included, a bus bar connecting the battery modules 100 may have a general form other than the safety bus bar 300, for example, a form made of a single copper plate. In addition, when the safety bus bar 300 is adopted as a pack bus bar on the negative electrode pack terminal 201(-) side, a normal pack bus bar, i.e., a pack bus bar of a general form made of a copper plate, may be adopted on the positive electrode pack terminal 201(+) side.

[0049] The safety bus bar 300 may be disposed in a portion where vent gas is discharged from the battery module 100. This will be described in more detail with further reference to Figures 5 and 6 in addition to Figures 1 to 4.

[0050] Fig. 5 is a cross-sectional view of the configuration of a battery pack according to one embodiment of the present invention as viewed from above. Fig. 6 is an enlarged perspective view of part A1 in Fig. 5. However, in Fig. 6, for convenience of illustration, the pack case 200 is omitted.

[0051] 5 and 6, when vent gas is generated inside any one of the battery modules 100, the vented gas may be discharged in the -Y-axis direction toward the front side as indicated by the arrows. In addition, a safety bus bar 300 may be located at the front side of the battery module 100, which is a path through which the vent gas is discharged.

[0052] In particular, the battery module 100 may include a module case 120 and a bus bar assembly 130, as shown in FIGS.

[0053] Here, the module case 120 may be configured to accommodate one or more secondary batteries in its internal space. For example, as shown in the figure, the module case 120 may include an upper plate 121, a lower plate 122, a side plate 123, and a rear plate 124. By joining these multiple plates together, it is possible to accommodate a battery assembly in a limited internal space.

[0054] Here, some of the plates included in the module case 120, for example, the lower plate 122 and the side plate 123, may be integrated together. In this case, the integrated shape of the lower plate 122 and the side plate 123 may be substantially U-shaped. Alternatively, the lower plate 122, the side plate 123 (left plate, right plate) and the upper plate 121 may be integrated together to form a tubular monoframe. The plates of such a module case 120 can define an internal space when joined together. Also, a cell assembly may be housed in such an internal space.

[0055] At least one side of the module case 120 may be open, and an electrode lead 111 of the cell assembly may be located in the open portion.

[0056] In particular, the battery module 100 may include a busbar assembly 130 coupled to an open portion of the module case 120. For example, as shown in FIGS. 3 and 4, the busbar assembly 130 may be coupled to the front open portion of the module case 120. An electrode lead 111 of the battery assembly may be located at the front of the module case 120. The busbar assembly 130 may also be coupled to the electrode lead 111. As a more specific example, the busbar assembly 130 may include a busbar housing 131 and a module busbar 132 as shown in FIGS. 3 and 4.

[0057] Here, the bus bar housing 131 may be made of an electrically insulating material, for example, a plastic material. The bus bar housing 131 may be configured so that the module bus bar 132 is placed and fixed thereon. The module bus bar 132 may be made of an electrically conductive material, for example, a metal material. The module bus bar 132 may be configured to electrically connect two or more electrode leads 111, or to be connected to one or more electrode leads 111 and transmit sensing information to a control unit such as a battery management system (BMS).

[0058] In this manner, in the case of the battery module 100 included in the battery pack according to the present invention, only a specific portion, for example, a front side where the bus bar assembly 130 is located, may be open, and the other portions may be sealed. In this case, when vent gas or the like is generated inside the battery module 100, the vent gas or the like may be induced to be discharged only to the open portion of the module case 120, for example, the front side where the bus bar assembly 130 is located. In particular, the bus bar assembly 130 may have a slit formed therein so that the electrode lead 111 can pass through. In this case, gas, sparks, flames, etc. inside the module may be discharged to the outside of the module case 120 through the slit of the bus bar assembly 130 as shown by the arrows in FIGS. 5 and 6.

[0059] Also, the safety busbar 300 may be located at a portion where the vent gas is discharged from the battery module 100. Therefore, in the battery pack according to the present invention, it can be said that each battery module 100 is configured to guide the vent gas generated inside to the safety busbar 300 side due to the configuration of the module case 120 and the busbar assembly 130. That is, it can be said that the safety busbar 300 is located at an open portion so that the vent gas can be discharged from the battery module 100. Also, when the vent gas is guided and discharged to the safety busbar 300 side in this manner, the power path of the safety busbar 300 may be blocked due to the temperature and / or pressure of the vent gas.

[0060] In particular, the safety busbar 300 may be configured to be at least partially severed by the vent gas, as will be described in more detail with further reference to FIG.

[0061] FIG. 7 is a diagram illustrating a schematic configuration in which the safety bus bar 300 in the configuration of FIG. 6 is cut by vent gas.

[0062] 7 together with FIG 6, when the vent gas is discharged to the front side of the battery module 100, particularly to the busbar assembly 130 side, the high-temperature vent gas may be discharged with high pressure to the safety busbar 300 located at the front side of the busbar assembly 130. In addition, due to the high temperature and pressure of the vent gas, a corresponding portion of the safety busbar 300 may be removed and cut. In particular, a certain portion of the safety busbar 300 may be crushed and removed due to the discharge of the vent gas.

[0063] In this case, the effect of cutting off the power path can be stably ensured by cutting the safety busbar 300. Furthermore, in this case, a predetermined portion of the safety busbar 300, particularly the electrically conductive portion, can also be completely removed in the form of fine particles. This makes it possible to prevent a short circuit caused by the cut safety busbar 300 coming into contact with the pack case 200, which is a conductor, or an electrode terminal of another polarity.

[0064] Also, at least a portion of the safety bus bar 300 may be fixed to the battery module 100 or the pack case 200. For example, the safety bus bar 300 may be fixed to the module case 120 or the bus bar assembly 130 of a plurality of battery modules 100. In this case, the position of the safety bus bar 300 can be fixed regardless of the ejection pressure of the vent gas, and the partial removal process by the vent gas can be performed more smoothly.

[0065] Meanwhile, as described above, in the case of the battery module 100 according to the present invention, only the front side may be configured in an open form, or the rear side may also be configured in an open form together with the front side. In this case, the configuration of the battery module 100 in Fig. 3 may include a bus bar assembly 130 instead of the rear plate 124. In this case, the rear case 220 of the pack case 200 may function as a duct similar to the front case 210.

[0066] FIG. 8 is a diagram illustrating a schematic configuration of a front end portion of a battery pack according to one embodiment of the present invention.

[0067] 1, 2, and 5, a battery pack according to the present invention may include a plurality of battery modules 100. In this case, the plurality of battery modules 100 may be stacked in at least one direction. For example, as shown in several drawings including FIG. 8, the battery pack may include eight battery modules 100 arranged side by side in the horizontal direction, particularly in the left-right direction (X-axis direction).

[0068] Here, the safety bus bar 300 may extend long along the stacking direction of the battery modules 100. That is, when the battery modules 100 are arranged side by side in the horizontal direction, the safety bus bar 300 may extend long in the horizontal direction. For example, as shown in Fig. 8, the safety bus bar 300 may extend long along the left-right direction (X-axis direction) which is the stacking direction of the battery modules 100.

[0069] Furthermore, a safety bus bar 300 can be used to connect between the pack terminal 201 and the module terminal 140 to provide a power path. In this case, it is necessary to connect the pack terminal 201 and the module terminal 140 of the battery module 100 located farthest from the pack terminal 201 located on one side of the pack case 200 to each other. In such a connection configuration, the safety bus bar 300 according to the present invention can be used.

[0070] For example, in the configuration of FIG. 8, the pack terminal 201 may be located at the left end of the battery pack. In this case, one of the module terminals 140 of the battery module 100 stacked on the rightmost side of the battery pack needs to be connected to the pack terminal 201. In this case, the safety bus bar 300 may be configured to extend long in the left-right direction in order to connect between the pack terminal 201 located on the left side of the battery pack and the module terminal 140 of the battery module 100 located on the right side of the battery pack. As a more specific example, the safety bus bar 300 may be provided in a form that connects between the negative pack terminal 201(-) located on the left side and the negative module terminal 140(-) of the battery module 100 arranged on the rightmost side.

[0071] Furthermore, each of the multiple battery modules 100 arranged side by side in the left-right direction may be configured to exhaust vent gas forward or backward. For example, in the configuration of Fig. 8 etc., each of the eight battery modules 100 has an open front side where the bus bar assembly 130 is located, as described above in Figs. 3 to 6 etc., and the vent gas can be exhausted forward (in the -Y axis direction) through such an open portion.

[0072] In this case, the safety bus bar 300 may be disposed on the front or rear side of the stack of the battery modules 100. For example, as shown in the configuration of FIG. 8 etc., one safety bus bar 300 may be disposed on the front or rear side of the eight battery modules 100 as a whole. In particular, when the vent gas is discharged from each battery module 100 to the front side, the safety bus bar 300 may be configured to extend long in the left-right direction and disposed on the front side of the eight battery modules 100. That is, the safety bus bar 300 may be disposed on the outside of an open portion of the battery module 100 from which the vent gas is discharged. Furthermore, when the vent gas is discharged from each battery module 100 to the slit side of the bus bar assembly 130, the safety bus bar 300 may be disposed on the outside of the bus bar assembly 130, for example, on the front side of the slit of the bus bar assembly 130.

[0073] According to the configuration of this embodiment of the present invention, even if vent gas is generated in any of the battery modules 100 among the plurality of battery modules 100 included in the battery pack, the safety bus bar 300 can be cut by the vent gas. Therefore, in this case, a configuration for ensuring safety during venting of the plurality of battery modules 100 can be effectively realized with one safety bus bar 300.

[0074] 9 is a schematic cross-sectional view of the configuration of a safety busbar 300 according to one embodiment of the present invention, viewed from above. For example, Fig. 9 can be said to be a diagram showing the cross-sectional configuration along the line A3-A3' in Fig. 7.

[0075] 9, the safety busbar 300 may be configured to include two or more different metals. In particular, the safety busbar 300 may include two or more metals having different melting points. In addition, the safety busbar 300 may include two or more metals having different electrical conductivities (conductivities).

[0076] For example, the safety busbar 300 may include a first metal in a portion indicated by M1 and a second metal in a portion indicated by M2 in Fig. 9. In this case, the second metal may be a metal having a lower melting point and lower electrical conductivity than the first metal. As a more specific example, the safety busbar 300 may include copper and aluminum.

[0077] According to the configuration of this embodiment of the present invention, a metal with a high melting point and electrical conductivity, for example, copper, is used to maintain the power transmission function of the safety busbar 300 itself at a certain level. Furthermore, when heat is applied by the vent gas to a metal with a low melting point and electrical conductivity contained in the safety busbar 300, the metal melts and separates or is removed from the safety busbar 300, thereby cutting the safety busbar 300 and stably performing the power path cutoff and short circuit prevention functions. Therefore, in this case, the safety busbar 300 can stably perform the power transmission function under normal circumstances and the power cutoff and short circuit prevention functions under emergency circumstances.

[0078] Furthermore, the safety busbar 300 may be configured by bonding two or more different metals together. In particular, the safety busbar 300 may be configured by bonding two or more metal plates together in a surface contact state. In this case, it can be said that the safety busbar 300 is configured of a clad metal having two or more metals.

[0079] For example, referring to the configuration of Fig. 9, the safety busbar 300 may be configured by joining a first metal plate and a second metal plate. Here, the first metal plate may be a metal plate made of copper, i.e., a copper plate, and the second metal plate may be a metal plate made of aluminum, i.e., an aluminum plate. In this case, it can be said that the safety busbar 300 has a clad metal made of copper and aluminum.

[0080] According to the configuration of this embodiment of the present invention, the power transmission function, power cut-off function, and short circuit prevention function can all be easily achieved by using two or more types of metal plates of different types, particularly those with different melting points.

[0081] In addition, when the safety busbar 300 includes two or more different metals, at least one of the metals may be melted by the vent gas. For example, the at least one metal included in the safety busbar 300 may be made of a material having a melting point lower than the temperature of the vent gas. As a more specific example, when the vent gas is generated from the battery module 100 included in the battery pack, if the temperature of the vent gas is about 950°C, the second metal plate may be made of a metal material having a lower melting point than the temperature of the vent gas. For example, the second metal plate may be made of an aluminum material having a melting point of about 660°C. Therefore, in this case, the second metal plate is easily melted by the vent gas during gas venting from the battery module 100. Furthermore, the molten material of the second metal plate may be detached from the safety busbar 300 by the pressure of the vent gas.

[0082] In this case, the first metal plate may be made of a material having a higher melting point than the second metal plate. In particular, the first metal plate may be made of copper having a melting point of about 1084°C. Even if the melting point of such a copper first metal plate is somewhat higher than the temperature of the vent gas, the thickness of the first metal plate may not be large due to the presence of the second metal plate. Therefore, the first metal plate may also be crushed and removed by the vent gas.

[0083] Furthermore, when the safety busbar 300 includes two or more metal layers having different melting points, the metal layer having a lower melting point may be formed thicker than the metal layer having a higher melting point. In other words, in the safety busbar 300, the metal layer having a higher melting point may be formed thinner than the metal layer having a lower melting point.

[0084] For example, in the embodiment of Figure 9, when the thickness of the first metal plate (first metal layer M1) is T1 and the thickness of the second metal plate (second metal layer M2) is T2, the safety busbar 300 can be designed so that T1 and T2 have the following relationship:

[0085] T1 <T2.

[0086] Furthermore, the first metal plate may be formed of two layers, an inner metal plate M11 and an outer metal plate M12. In this case, when the thickness of the inner metal plate M11 is T11 and the thickness of the outer metal plate M12 is T12, the thickness T1 of the first metal plate M1 is the sum of the thickness T11 of the inner metal plate M11 and the thickness T12 of the outer metal plate M12. In this case, the second metal plate M2 can have a thickness larger than the sum of the thicknesses of the inner metal plate M11 and the outer metal plate M12.

[0087] The thickness of the second metal plate may be at least twice, further 3 to 4 times, or further 7 to 8 times that of the first metal plate. For example, when a copper plate is used as the first metal plate and an aluminum plate is used as the second metal plate, the thickness T1 of the copper plate may be 0.05 mm, and the thickness T2 of the aluminum plate may be 0.45 mm.

[0088] According to the above-described configuration of the present invention, it is possible to more stably ensure the power transmission, cutoff function, and short circuit prevention function of the safety busbar 300. That is, according to the configuration of the above-described embodiment, even if the safety busbar 300 includes a first metal plate having a high melting point but good electrical conductivity in order to improve the power transmission function, the safety busbar 300 can include a relatively large amount of the second metal plate having a low melting point. Therefore, in an emergency, the power cutoff and short circuit prevention functions of the safety busbar 300 can be more effectively achieved by the vent gas.

[0089] Meanwhile, the safety busbar 300 may further include an insulating layer P. The insulating layer P may be made of an electrically insulating material, for example, a plastic material, and may be located outside the safety busbar 300. For example, as shown in FIG. 9, the insulating layer P may be configured to encase the first metal layer M1 and the second metal layer M2. Therefore, in the case of the cross-sectional configuration shown in the embodiment of FIG. 9, the safety busbar 300 may include the inner insulating layer P, the first metal layer M1 (inner metal plate), the second metal layer M2, the first metal layer M1 (outer metal plate), and the outer insulating layer P.

[0090] In this manner, according to the embodiment in which the outside of the safety busbar 300 is wrapped with the insulating layer P, the conductors such as the first metal layer M1 and the second metal layer M2 are not exposed to the outside under normal conditions. Therefore, under normal conditions, it is possible to prevent problems such as leakage and short circuits caused by contact between the safety busbar 300 and the conductors around it. However, such an insulating layer P can be melted by vent gas. Nevertheless, according to the configuration of the above embodiment of the present invention, even the metal layers contained inside are melted or crushed and removed by the vent gas, so that the short circuit prevention function of the safety busbar 300 can be more stably ensured.

[0091] The safety busbar 300 may have a high melting point metal layer formed in multiple layers. For example, as described above in the embodiment of Fig. 9, the first metal plate (first metal layer M1) having a relatively high melting point, for example, a copper plate, may be formed in multiple layers. That is, in the embodiment of Fig. 9, the first metal plate is a copper plate, and it can be said to have an inner copper plate and an outer copper plate.

[0092] In particular, such a plurality of first metal plates may be disposed on both sides of a second metal plate having a low melting point. For example, the safety busbar 300 may be configured in a form having metal layers including one aluminum layer and two copper layers disposed on both sides of the aluminum layer.

[0093] According to this embodiment of the present invention, the thickness of the first metal plate may be made thinner. That is, when the thickness of the first metal plate needs to be more than a certain value in order to ensure the electrical conductivity of the safety busbar 300, the first metal plate may be made of a plurality of layers, and each layer may be made thin. For example, when the thickness of the first metal plate needs to be more than 0.05 mm in order to ensure the electrical conductivity of the safety busbar 300, the thickness of 0.05 mm may be divided into two or more, and the thickness of each of the first metal plates may be made thin. For example, when the first metal plate is made of an inner metal plate and an outer metal plate, each of the inner metal plate and the outer metal plate may be 0.025 mm.

[0094] According to this embodiment of the present invention, the electrical conductivity of the safety busbar 300 can be stably maintained by ensuring that the overall thickness of the first metal plate M1 is at least a certain value. In addition, by reducing the thickness of each of the first metal plates M1, the pulverization effect into powder or the like by the vent gas can be easily achieved. In particular, when the first metal plate is a copper plate, the melting point of copper may be higher than the temperature of the vent gas, but the thinner the thickness, the more easily the decomposition effect by the vent gas can be achieved.

[0095] Furthermore, when the first metal plate M1 includes an inner metal plate and an outer metal plate, the inner metal plate can have the same thickness as the outer metal plate. In this case, the thicknesses of the inner metal plate and the outer metal plate can be made as thin as possible, so that the disassembly effect of the first metal plate can be more easily achieved.

[0096] Alternatively, the thickness of the inner metal plate may be thinner than the thickness of the outer metal plate in the safety busbar 300. When the vent gas is exhausted from the battery module 100, the vent gas may first collide with the inner metal plate. In this case, the thinner the inner metal plate is, the easier it is to remove the inner metal plate and the faster it is to melt the second metal plate.

[0097] Meanwhile, as described above, the safety bus bar 300 can achieve a power cut-off and short circuit prevention function by being at least partially cut by the vent gas discharged from the battery module 100. In this case, other components of the battery pack, for example, the battery module 100, may be configured to more easily implement a configuration for cutting the safety bus bar 300 by the vent gas. An embodiment related to this will be described in more detail with reference to FIG.

[0098] Fig. 10 is a cross-sectional view showing a schematic configuration of some components of a battery pack according to an embodiment of the present invention. In particular, for convenience of explanation, Fig. 10 shows the bus bar housing 131 and the safety bus bar 300 of the bus bar assembly 130, excluding other components.

[0099] 10, the bus bar housing 131 may have slits S1 to S6 formed therein, penetrating from the inside to the outside of the battery module 100. In FIG. 10, the left side is the inside portion of the battery module 100, and the right side is the outside portion of the battery module 100. Furthermore, the electrode leads 111 of the secondary batteries may be inserted into these slits S1 to S6 and connected to the outer module bus bar 132. Furthermore, when vent gas is generated inside the battery module 100, the vent gas may be discharged to the outside through these slits S1 to S6, as shown by the arrows.

[0100] At this time, the slits S1 to S6 of the busbar assembly 130, particularly the slits of the busbar housing 131, may be configured so that the vent gas that has passed through them is directed towards the safety busbar 300. To explain the configuration in Fig. 10 in more detail, the safety busbar 300 may be located on the front side (outside) of the busbar assembly 130. At this time, at least some of the slits S1 to S6 of the busbar assembly 130 may have an inclined shape so that the vent gas flows in the direction in which the safety busbar 300 is located.

[0101] Furthermore, the safety busbar 300 is located on the front side of the busbar assembly 130, but may be located in the center in the up-down direction (Z-axis direction). In this case, at least a part of the slits S1 to S6 of the busbar assembly 130 may be configured to be inclined toward the center on the front side. That is, the slits S1 and S2 located in the busbar assembly 130 above the safety busbar 300 in the vertical direction (Z-axis direction) may be configured to be inclined downward from the inside to the outside. Also, the slits S5 and S6 located in the busbar assembly 130 below the safety busbar 300 in the vertical direction (Z-axis direction) may be configured to be inclined upward from the inside to the outside. And, the slits S3 and S4 located in the center in the up-down direction of the busbar assembly 130 are located in the same position as the safety busbar 300 in the vertical direction (Z-axis direction), so the gas discharge direction may be configured to be horizontal (parallel to the ground).

[0102] According to this configuration of the present invention, the vent gas that has passed through the slits of the busbar assembly 130 can be concentrated on the safety busbar 300. This can further improve the cutting and removal effect of the safety busbar 300.

[0103] In addition, when the slits of the busbar assembly 130 are inclined, the inclination angles of at least some of the slits may be different from each other. Here, the inclination angle may be an angle inclined from the horizontal direction (Y-axis direction).

[0104] Furthermore, the inclination angles may be different between slits that are inclined downward. For example, in the embodiment of Fig. 10, slits S1 and S2 that are located above the safety busbar 300 may be inclined downward, but may have different gradients. In particular, the slit S1 located relatively above may be configured to have a larger downward inclination angle than the slit S2 located relatively below. In other words, the slits located higher than the safety busbar 300 in the vertical direction may be configured to have a larger downward inclination angle.

[0105] Also, the inclination angles may be different between slits that are inclined upward. For example, in the embodiment of Fig. 10, slits S5 and S6 that are located below the safety busbar 300 may be inclined upward, but may have different gradients. In particular, the slit S6 located relatively lower may be configured to have a larger upward inclination angle than the slit S5 located relatively higher. That is, the lower the slit is located below the safety busbar 300 in the vertical direction, the larger the upward inclination angle may be formed.

[0106] That is, when multiple slits are included as in the above embodiment, a slit located further away in the vertical direction than the safety busbar 300 may have a relatively large inclination angle.

[0107] This embodiment of the present invention can further enhance the effect of concentrating the vent gas that has passed through the slits on the safety busbar 300. Therefore, in this case, the effect of cutting and removing the safety busbar 300 by the vent gas can be further enhanced.

[0108] Fig. 11 is a perspective view that illustrates a schematic view of some components of a safety bus bar 300 according to another embodiment of the present invention. In particular, Fig. 11 illustrates the inner surface of the safety bus bar 300, i.e., the surface viewed from the battery module 100. This embodiment will be described while focusing on the differences from the above-described embodiment.

[0109] 11 , a groove G may be formed in the safety busbar 300. The groove G may be formed in a concave shape from the surface of the safety busbar 300 toward the inside. In particular, the groove G may be formed in a concave shape from the inner surface of the safety busbar 300 toward the outside of the battery pack. Furthermore, the groove G may be formed in a shape that reduces the thickness of the safety busbar 300.

[0110] The configuration of this embodiment of the present invention makes it possible to more effectively cut the safety busbar 300 with the vent gas. In particular, when the vent gas is ejected from the battery module 100 side toward the safety busbar 300 as shown by the arrows in Fig. 11, the groove G makes it easier to cut the safety busbar 300 with the vent gas.

[0111] Furthermore, in this case, the cutting position of the safety busbar 300 by the vent gas can be guided by the groove G. In particular, as shown in FIG. 11, two grooves G may be formed on both sides of the portion of the safety busbar 300 that encounters the vent gas. In this case, the vent gas may be ejected into the portion between the two grooves G, and the portion between the two grooves G may be lost due to the vent gas. Therefore, in this case, the safety busbar 300 can be cut more reliably, and the cutting position can be clearly defined.

[0112] 12 is a perspective view showing a schematic view of some components of a safety bus bar 300 according to still another embodiment of the present invention. FIG. 12 also shows the inner surface of the safety bus bar 300.

[0113] 12, groove G may be formed so as to directly encounter a portion of the inner surface of the safety busbar 300 from which the vent gas is ejected. That is, as shown by the arrows in Fig. 12, groove G of the safety busbar 300 may be formed in a portion that encounters the vent gas when the vent gas is ejected from the battery module 100 side. In this case, groove G may be formed with an area larger than that of groove G formed in the embodiment of Fig. 11.

[0114] According to the configuration of this embodiment of the present invention, even if there is one groove G, it is possible to obtain an effect of improving the cutting force of the safety bus bar 300 by the vent gas. In this case, it is also possible to further improve the manufacturing processability of the safety bus bar 300 and the battery pack.

[0115] Fig. 13 is a cross-sectional view that shows a schematic view of some components of a safety busbar 300 according to still another embodiment of the present invention. For example, Fig. 13 is a cross-sectional view of the configuration of the safety busbar 300 seen from above. Furthermore, Fig. 13 shows a modified example of the embodiment shown in Fig. 12.

[0116] 13, the groove G may be formed in a portion of the inner surface of the safety busbar 300 that encounters the vent gas. In this case, the groove G of the safety busbar 300 may have an inclined surface that inclines in a specific direction as indicated by GS. In this case, the inclined surface GS may be formed in a shape such that the thickness of the safety busbar 300 becomes thinner toward the center portion GC of the groove G. In other words, the groove G of the safety busbar 300 may be configured in a shape that becomes deeper from both ends toward the center portion GC.

[0117] According to the configuration of this embodiment of the present invention, when the vent gas is ejected into the groove G of the safety busbar 300, the vent gas can be concentrated at a specific portion of the groove G, as shown by the arrows in Fig. 13. In particular, the vent gas moves to the central portion GC of the groove G along the inclined surface GS of the groove G, so that the heat and pressure of the vent gas can be further concentrated at the central portion GC of the groove G. This makes it possible to cut the safety busbar 300 more quickly and reliably. As a result, the cutting effect of the safety busbar 300 by the vent gas can be further improved.

[0118] The battery pack according to the present invention may further include various other components of a battery pack known at the time of filing of the present invention, for example, a battery management system (BMS), a current sensor, a fuse, and other components.

[0119] An energy storage system according to the present invention may include one or more battery packs according to the present invention. In particular, the energy storage system may include a plurality of packs according to the present invention, the packs being electrically connected to each other to provide a large energy capacity. Furthermore, the energy storage system according to the present invention may further include various other components of energy storage systems known at the time of filing of the present application. Moreover, such energy storage systems may be used in various locations and devices, such as smart grid systems and charging stations.

[0120] Furthermore, the automobile according to the present invention may include one or more battery packs according to the present invention. Furthermore, the automobile according to the present invention may further include, in addition to such a battery pack, various other components included in the automobile. For example, the automobile according to the present invention may further include, in addition to the battery pack according to the present invention, a vehicle body, a motor, a control device such as an electronic control unit (ECU), and the like.

[0121] Meanwhile, in this specification, terms indicating directions such as up, down, left, right, front, and back may be used, but these terms are merely for convenience of explanation, and it will be obvious to those skilled in the art of the present invention that they may change depending on the position of the object of interest, the position of the observer, etc.

[0122] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the scope of the technical concept of the present invention and the scope of the claims. [Explanation of symbols]

[0123] 100 Battery Module 110 Battery Cell 111 Electrode lead 120 Module Case 121 Upper Plate 122 Lower Plate 123 Side Plate 124 Rear plate 130 Busbar Assembly 131 Busbar housing 132 module busbar 140 Module Terminal 200 pack case 210 Front Case 220 Rear Case 230 Left Case 300 Safety Busbar H1 outlet M1 1st metal layer M2 2nd metal layer P insulating layer S1~S6 Slits G groove

Claims

1. a battery module including one or more battery cells and a module terminal; a pack case that covers at least a portion of an exterior of the battery module and has a pack terminal provided on at least one side thereof; a safety bus bar connected between the module terminal and the pack terminal or between the module terminals to provide a power path and to cut off the power path by vent gas discharged from the battery module; Including, the safety busbar includes two or more types of metal layers at least in a portion toward which vent gas discharged from the battery module is directed, the metal layers including a first metal layer and a second metal layer having a melting point and electrical conductivity lower than those of the first metal layer; Battery pack.

2. The safety bus bar is disposed at a portion where vent gas is discharged from the battery module.

2. The battery pack of claim 1.

3. A battery pack includes a plurality of the battery modules, stacked in at least one direction; The safety bus bar extends longitudinally along the stacking direction of the battery modules.

3. The battery pack according to claim 1 or 2.

4. The battery modules are arranged side by side in the left-right direction, and the vent gas is discharged forward or backward; The safety bus bar is disposed in front or behind a stack of multiple battery modules.

4. The battery pack according to claim 3.

5. The safety bus bar is formed by bonding the first metal layer and the second metal layer to each other.

2. The battery pack of claim 1.

6. The safety bus bar is configured such that at least the second metal layer is meltable by the vent gas.

2. The battery pack of claim 1.

7. The safety bus bar is formed such that the second metal layer is thicker than the first metal layer.

7. The battery pack according to claim 6.

8. The safety busbar has the first metal layer formed of a plurality of layers.

8. The battery pack according to claim 7.

9. 3. An energy storage system comprising the battery pack of claim 1 or 2.

10. A motor vehicle comprising the battery pack according to claim 1 or 2.

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