BATTERY PACK AND DEVICE INCLUDING THE SAME

A battery pack includes: a plurality of battery modules; a venting inducing frame disposed along an edge of the battery modules and forming a venting passage; a venting gate for connecting an inside of the battery modules and the venting inducing frame; a rupture portion formed on an outside of the venting inducing frame; and a unidirectional valve formed on a passage of the venting inducing frame, wherein the unidirectional valve intercepts a passage in a direction connected to a venting gate connected to a second battery module from the venting gate connected to one battery module from among the battery modules, and opens a passage in a direction connected to the rupture portion from the venting gate connected to one battery module from among the battery modules.

TECHNICAL FIELD

This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0052258 filed in the Korean Intellectual Property Office on Apr. 29, 2020, the entire contents of which are incorporated herein by reference.

The present invention relates to a battery pack and a device including the same, and in particular, it relates to a safety-improved battery pack and a device including the same.

BACKGROUND ART

Rechargeable batteries having high application characteristics and electrical characteristics such as high energy density according to their products are widely applied to battery vehicles, hybrid vehicles, and electric power storage devices driven by electric driving sources, as well as portable devices. These rechargeable batteries are attracting attention as new energy sources for improving environmental friendliness and energy efficiency in that they do not generate any by-products of energy use, as well as their primary merit that they can drastically reduce the use of fossil fuels.

The commercially available secondary batteries include a nickel cadmium battery, a nickel hydrogen battery, a nickel zinc battery, and a lithium secondary battery, and the lithium secondary battery among them scarcely generates a memory effect compared to the nickel-based secondary battery so it is freely charged and discharged, a self-discharge rate is very low, and an energy density is high as merits.

The lithium secondary battery generally uses a lithium-based oxide and a carbon material as a positive active material and a negative active material, respectively. The lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate on which the positive active material and the negative active material are respectively applied are disposed with a separator therebetween, and an exterior material, that is, a battery case, for sealing and receiving the electrode assembly together with an electrolyte solution.

In general, the lithium secondary battery may be classified into a cylindrical or square-type secondary battery of which the electrode assembly is installed in a metal can, and a pouch-type secondary battery of which the electrode assembly is installed in a pouch of an aluminum laminate sheet, depending on a shape of the exterior material.

Recently, as needs for a large-capacity secondary battery structure increase in addition to the use as an energy storing source of the secondary battery, needs for the battery packs in a medium to large module structure in which battery modules in which a plurality of secondary batteries are coupled in series or in parallel are gathered are increasing. Capacity and outputs of the battery modules are improved by coupling a plurality of battery cells in series or in parallel and configuring a battery cell stacked body. Further, a plurality of battery modules may configure a battery pack when installed together with various control and protection systems such as a battery management system (BMS) or a cooling system.

The battery pack has a structure in which a plurality of battery modules are combined, so when some of the battery modules receive an overvoltage or an overcurrent or they are overheated, safety and operation efficiency of the battery pack may be problematic. Particularly, while the capacity of the battery pack is in the increasing trend to improve mileage and energy inside the pack is accordingly increasing, there is a need to design a structure satisfying reinforcing safety standards and obtaining safety of vehicles and drivers. For this purpose, the need for acquiring a structure for preventing an internal thermal runaway in advance, and minimizing corresponding damages when the thermal runaway is generated, is particularly on the rise.

DISCLOSURE

The present invention has been made in an effort to provide a safety-improved battery pack and a device including the same.

However, the objective of the present invention is not limited to the aforementioned one, and may be extended in various ways within the spirit and scope of the present invention.

An embodiment of the present invention provides a battery pack including: a plurality of battery modules; a venting inducing frame disposed along an edge of the battery modules and forming a venting passage; a venting gate for connecting an inside of the battery modules and the venting inducing frame; a rupture portion formed on an outside of the venting inducing frame; and a unidirectional valve formed on a passage of the venting inducing frame, wherein the unidirectional valve intercepts a passage in a direction connected to a venting gate connected to a second battery module from the venting gate connected to one battery module from among the battery modules, and opens a passage in a direction connected to the rupture portion from the venting gate connected to one battery module from among the battery modules.

The unidirectional valve may be opened or closed according to a direction in which a pressure is applied.

The venting inducing frame may include a pair of vertical beams formed in parallel to a first direction and a pair of horizontal beams formed in parallel to a second direction traversing the first direction, the vertical beams and the horizontal beams respectively may include a cover formed in a length direction of the vertical beams and the horizontal beams, and a passage surrounded by the cover and formed to allow gas to pass through, and the at least one unidirectional valve may be formed on the passage.

A1-1passage and a1-2passage may be formed on the pair of vertical beams, respectively, a2-1apassage and a2-1bpassage may be separately formed in one of the pair of horizontal beams, and a2-2apassage and a2-2bpassage may be separately formed in the other of the pair of horizontal beams.

The unidirectional valve may be respectively formed on one of the1-1passage, the2-1a passage, and the2-2apassage connected to each other, and on one of the1-2passage, the2-1bpassage, and the2-2bpassage connected to each other.

A notch may be formed in a middle of the pair of horizontal beams, and the2-1apassage and the2-1bpassage, and the2-2apassage and the2-2bpassage, may be formed on respective sides of the notch.

The venting gate may be connected to one of the passages formed on respective sides of the notch.

A rupture portion may be formed on respective sides of one of the pair of horizontal beams, and the rupture portion may be respectively connected to the2-1apassage and the2-1bpassage.

The battery pack may further include a housing for receiving the battery modules and the venting inducing frame, wherein the housing may include an upper cover and a lower housing, and a pack gasket may be formed between the upper cover and the lower housing.

Another embodiment of the present invention provides a device including the above-described battery pack. According to the embodiments, the venting inducing structure is provided in the battery pack, so when an abnormal phenomenon is generated in the battery cell, the safety of the battery pack may be secured by inducing venting gas in a predetermined direction.

MODE FOR INVENTION

Parts that are irrelevant to the description will be omitted to clearly describe the present invention, and the same elements will be designated by the same reference numerals throughout the specification.

The size and thickness of each configuration shown in the drawings are arbitrarily shown for better understanding and ease of description, but the present invention is not limited thereto. In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. For ease of description, the thicknesses of some layers and areas are exaggerated.

Further, throughout the specification, the phrase “in a plan view” means viewing a target portion from the top, and the phrase “in a cross-sectional view” means viewing a cross-section formed by vertically cutting a target portion from the side.

FIG.1shows a battery module according to an embodiment of the present invention.FIG.2shows a perspective view of a battery module ofFIG.1seen from bottom to top in a z-axis direction.

Referring toFIG.1andFIG.2, the battery module100included in the battery pack ofFIG.1may include a battery cell stacked body102in which a plurality of battery cells101are stacked, a module frame108for receiving the battery cell stacked body102, and an end plate120. The battery cells101are stacked to be mutually electrically connected to each other to configure the battery cell stacked body102. Particularly, as shown inFIG.1, a plurality of battery cells101may be stacked in a direction that is parallel to the y-axis.

In this instance, the battery cell stacked body102according to an embodiment of the present invention may be a large-area module including a greater number of the battery cells101than the prior art. For example,48battery cells101may be included per battery module100. Regarding the large-area module, a horizontal direction length of the battery module becomes long. In this instance, the horizontal direction length may signify a direction in which the battery cells101are stacked, that is, the length in the direction that is parallel to the y-axis.

The module frame108for receiving the battery cell stacked body102may include an upper plate112and a lower frame111. The lower frame111may be a U-shaped frame. The U-shaped frame may include a bottom portion and two lateral portions extending upward from respective ends of the bottom portion. The bottom portion may cover a lower side (an opposite direction of a z axis) of the battery cell stacked body102, and the lateral portions may cover respective lateral sides (the y-axis direction and its opposite direction) of the battery cell stacked body102.

The upper plate112may be formed to have one plate-shaped structure for surrounding a remaining upper side (z-axis direction) excluding the lower side and the respective sides surrounded by the U-shaped frame. The upper plate112and the lower frame111may be combined to each other by welding while corresponding corners contact each other, thereby configuring a structure for covering the battery cell stacked body102from top to bottom and from right to left. The battery cell stacked body102may be physically protected through the upper plate112and the lower frame111. For this purpose, the upper plate112and the lower frame111may include a metallic material with predetermined rigidity.

A venting gate121for communicating with an inside of the battery module100and releasing a flame or heat that may be generated in the inside is disposed on the end plate120according to the present embodiment. The venting gate121may be provided on a lower side of the end plate120by considering a connector connecting portion for transmitting information. The venting gate121may be connected to an opening (not shown) formed in part of the end plate120, and it may communicate with an inside of the battery module100.

The module frame108may include a module frame protrusion131formed so that the bottom portion of the module frame108may extend to pass through the end plate120. In this instance, a coolant input and output by a cooling port140connected to an upper side of the module frame protrusion131may be supplied to/discharged from a heat sink130through the module frame protrusion131.

FIG.3shows an exploded perspective view of a battery pack according to an embodiment of the present invention.

Referring toFIG.3, the battery pack1000according to an embodiment of the present invention includes a plurality of battery modules100, and a venting inducing frame300disposed along an edge of a plurality of battery modules100. The battery modules100and the venting inducing frame300may be mounted on a pack tray200and may be received in a pack housing400.

The pack housing400may include a lower housing410for receiving the pack tray200, and an upper cover420combined to the lower housing410and covering an upper side of the battery module100. A pack gasket411may be formed between the upper cover420and the lower housing410to close and seal the inside of the pack housing400.

The battery modules100respectively include a battery cell stacked body disposed in the module frame110, and include an end plate120for covering the battery cell stacked body exposed to the respective ends of the module frame110. In this instance, one of the respective end plates120includes a venting gate121communicating with the inside of the battery module100and releasing the flame or heat that may be generated from the inside. In the battery pack1000, the venting gate121is disposed to face an external side of the battery pack1000, and preferably, as shown inFIG.3, the venting gate121may be disposed to face the external side toward the respective ends in the first direction (x-axis direction) in the battery pack1000.

A venting inducing frame300may be disposed along the edge of all the battery modules100. The venting inducing frame300may include a pair of vertical beams310and a pair of horizontal beams320formed in a pipe shape along the respective sides of the battery pack1000and respectively extending in the first direction (x-axis direction) and the second direction (y-axis direction), and they are formed to communicate with each other as a whole body. A detailed configuration of the venting inducing frame300will be described in a later portion of the present specification.

The battery modules100and the venting inducing frame300may be mounted on the pack tray200, and may be fixed to the pack tray200by a fixation means as needed. The battery module100, the venting inducing frame300, and the pack tray200may be received in the lower housing410. The lower housing410may include a bottom side on which the pack tray200is disposed, and a side wall extending upward from the edge of the bottom side. An upper cover420for covering the upper portion of the battery module100may be combined to the lower housing410to protect an internal electrical field. In this instance, various control and protection systems such as a battery management system (BMS) and a cooling system together with the battery module100may be installed in the pack housing400.

At least one rupture portion500for discharging heat or flame generated from the inside to the outside may be formed on one side wall of the lower housing410. A detailed configuration of the rupture portion500will be described in a later portion of the present specification.

A venting inducing frame of a battery pack according to an embodiment of the present invention will now be described in detail.

FIG.4shows an exploded perspective view of a venting inducing frame in a battery pack ofFIG.3.

Referring toFIG.3andFIG.4, the venting inducing frame300is formed in a pipe shape along the respective sides of the battery pack1000, it may include a pair of vertical beams310and a pair of horizontal beams320respectively extending in the first direction (x-axis direction) and the second direction (y-axis direction), and they are formed to communicate with each other as a whole body.

The vertical beams310have a pipe shape lengthily extending in the first direction (x-axis direction), and include a cover311for defining an inside of the pipe shape, and a passage312formed inside the cover311. The cover311may include a first internal cover311adisposed near the battery module100in the second direction (y-axis direction), and a first external cover311bfacing the same and disposed to become distant from the battery module100in the second direction (y-axis direction). At least one of the first internal cover311aand the first external cover311bincludes a groove lengthily formed in the first direction. That is, its cross-section is formed to have a “⊏” shape (formed to have a shape in which one side is removed from a square pipe shape), and the cover of the other is combined thereto to thus define the passage312. However, it is not limited thereto as long as the pipe shape may be obtained by the cover311.

The horizontal beams320have a pipe shape lengthily extending in the second direction (y-axis direction), and includes a cover321for defining an inside of the pipe shape, and a passage322formed inside the cover321. The cover321may include a second internal cover321adisposed near the battery module100in the first direction (x-axis direction), and a second external cover321bfacing the same and disposed to become distant from the battery module100in the first direction (x-axis direction). At least one of the second internal cover321aand the second external cover321bincludes a groove lengthily formed in the second direction That is, its cross-section is formed to have a “⊏” shape (formed to have a shape in which one side is removed from a square pipe shape), and the cover of the other is combined thereto to thus define the passage322. Particularly, in the present embodiment, as shown inFIG.2, the second internal cover321aand the second external cover321bmay be respectively formed to have a “⊏” shaped cross-section, and by this, rigidity when the horizontal beams320are assembled may be increased. However, this is not limited thereto when the pipe shape may be obtained by the cover321.

The horizontal beams320includes a first connection hole324formed on the side facing the battery module100, that is, one side of the second internal cover321a.The first connection hole324is disposed to communicate with the venting gate121of the battery module100. The horizontal beams320further includes a third connection hole326formed on the side disposed in a direction becoming distant in the second direction from the battery module100, that is, one side of the second external cover321b.The third connection hole326is disposed so that the rupture portion500may communicate with the passage322. In this instance, the venting path bracket328may combine the rupture portion500and the horizontal beams320to guide the path for the venting gate121, the passage322of the horizontal beams320, and the rupture portion500to communicate with each other.

The vertical beams310include a second connection hole314formed on the first internal cover311aat the respective ends disposed near the horizontal beams320. The passage322of the horizontal beams320may communicate with the passage312of the vertical beams310through the second connection hole314.

The rupture portion500is connected to the passage322of the horizontal beams320and includes a rupture side (510, shown inFIG.7B) that is broken when input gas has more than a predetermined level of pressure. Further, the rupture portion500includes a wing portion (520, shown inFIG.7B) protruding from a body on which the rupture side510is formed and combining to the side wall of the lower housing410. The wing portion520may be fixed to the lower housing410by use of a fastening means such as a screw.

In the present embodiment, the rupture portion500is connected to the passage322of the horizontal beams320, and the rupture portion500is fixed with the horizontal beams320and the lower housing410, and without being limited thereto, configurations for communicating with the passage of the venting inducing frame300and discharging to the outside may be appropriately used. Further, the formation of two rupture portions500on one of the pair of horizontal beams320is exemplified in the present embodiment, and without being limited thereto, the rupture portion500may be installed in the horizontal beams320on another side, or it may be installed in the vertical beams310, and corresponding positions and numbers may be appropriately selected as needed.

By the above-noted configuration, the passage is formed to communicate with all components inside the venting inducing frame300in a square shape configured with the vertical beams310and the horizontal beams320, and the passage communicates with the venting gate121of the battery module100and the rupture portion500to induce heat and flame to the outside and minimize the influence to peripheral battery modules when a thermal runaway is generated from the battery module100. In this instance, the flame included in the generated high-pressure venting gas is combusted while passing through the path inside the venting inducing frame300and it may be discharged to the outside in a safer way. In the normal condition without a thermal runaway, the venting inducing frame300may function as a support frame for stably supporting the battery module100and may improve stability of the battery pack1000.

A path for controlling a case in which issues such as overvoltage, overcurrent, or overheating are generated in some battery modules in the battery pack will now be described.

FIG.5shows a mimetic diagram of a transfer path when a thermal runaway is generated on a certain module of a battery pack according to an embodiment of the present invention.FIG.6shows an enlarged portion IV ofFIG.5.FIG.7AandFIG.7Bshow an enlarged portion V ofFIG.5.

Referring toFIG.3toFIG.7, when abnormal phenomena (heat issues) such as overvoltage, overcurrent, or overheating are generated in the battery module100, high-pressure venting gas is discharged from the inside of the battery module100through the venting gate121. In this instance, high-temperature and high-pressure gas and flames are induced to the first connection hole324positioned nearest the venting gate121of the battery module100in which heat is generated. The high-temperature and high-pressure gas and flames input through the first connection hole324may be discharged to the outside through the passage formed on the venting inducing frame300.

For example, when heat is generated in the battery module100disposed on the position1inFIG.5, as shown inFIG.6, the high-pressure gas and flames may be discharged through the venting gate121, may pass through the passage322of the horizontal beams320, may be directly induced to the rupture portion500, and may be discharged to the outside. By this, the heat generated by the battery module100on the position1may be discharged to the outside without giving an influence to the peripheral module.

Further, when heat is generated in the battery module100disposed on the position2inFIG.5, as shown inFIG.7AandFIG.7B, the high-temperature and high-pressure gas and flames are discharged through the venting gate121, and are input to the passage322of the horizontal beams320. The high-temperature and high-pressure gas and flames having been input to the passage312of the vertical beams310through the second connection hole314and having moved along the passage312may be induced to the horizontal beams320on the side where the rupture portion500is positioned and may be finally discharged to the outside through the rupture portion500through the second connection hole314formed on the opposite end of the corresponding vertical beams310. That is, when heat is generated in the battery module100, high-temperature and high-pressure gas and flames may be induced and may be finally discharged to the outside on the passage of the venting inducing frame300through the first connection hole324positioned nearest the venting gate121of the corresponding battery module100.

Referring toFIG.7B, the passage of the venting gate121and the passage of the rupture portion500may be formed to cross each other. When the passages of the venting gate121and the rupture portion500are positioned in the same line, the high-temperature and high-pressure gas and flames having passed through the venting gate121are transmitted to the rupture portion500, so the rupture side510shown inFIG.7Bmay be easily broken and the rupture portion500may be damaged. According to the present embodiment, the passage of the rupture portion500and the passage of the venting gate121cross each other, the high-temperature and high-pressure gas and flames having passed through the venting gate121may pass through the passage in the venting inducing frame300formed to be vertical to the direction of the passage of the venting gate121, and may be induced to the rupture portion500formed to be vertical to the venting inducing frame300, and the high-temperature and high-pressure gas and flames reach the rupture portion500according to direction switching, so the pressure transmitted to the rupture side510is reduced, and the high-temperature and high-pressure gas and flames may be stably discharged to the rupture portion500.

A battery pack in which a unidirectional valve is formed according to an embodiment of the present invention will now be described.

FIG.8shows a schematic view in which a unidirectional valve according to an embodiment of the present invention is opened.FIG.9shows a schematic view in which a unidirectional valve according to an embodiment of the present invention is closed.

The unidirectional valve600may be opened or closed according to the direction in which a pressure is applied. As shown inFIG.8, when the high-temperature and high-pressure gas and flames are input to one side of the unidirectional valve600formed in the venting inducing frame300to pressurize the unidirectional valve600, the unidirectional valve600is opened and the high-temperature and high-pressure gas and flames may pass through the unidirectional valve600, and when the high-temperature and high-pressure gas and flames are input to another side of the unidirectional valve600to pressurize the unidirectional valve600as shown inFIG.9, the unidirectional valve600is closed, and the high-temperature and high-pressure gas and flames fails to pass through the unidirectional valve600. A structure for preventing backward flowing of gas and flames using the above-structured unidirectional valve600will be described in a later portion of the present specification.

FIG.10shows a battery pack in which a venting inducing frame is formed without a unidirectional valve according to a comparative example.FIG.11shows that a unidirectional valve according to an embodiment of the present invention is formed on a passage of horizontal beams.FIG.12shows that a unidirectional valve according to another embodiment of the present invention is formed on a passage of vertical beams.

According to the present specification, the unidirectional valve600is formed on the passage of the venting inducing frame300. Referring toFIG.11andFIG.12, the unidirectional valve600intercepts the passage in a direction connected to the venting gate121connected to a second battery module on the venting gate121connected to a first battery module from among a plurality of battery modules100, and opens the passage in a direction connected to the rupture portion500on the venting gate121connected to the first battery module from among the battery modules100.

According to what is shown with reference toFIG.10, regarding the battery pack according to a comparative example of the present invention, the venting inducing frame30may be connected to venting gates12respectively connected to the battery modules10. However, when high-temperature and high-pressure gas and flames are generated from one of the battery modules10, the gas and the flames having passed through the venting gate12and having been input to the venting inducing frame30are not discharged to the outside through the rupture portion50, but may pass through the venting gate12formed in another battery module and may be input into the other battery module. When the high-temperature and high-pressure gas and flames generated by one battery module are not discharged to the outside through the rupture portion but flow back to another battery module, the battery pack may be damaged, and the venting inducing frame may not well perform a venting function.

As shown inFIG.11andFIG.12, regarding the battery pack1000, the unidirectional valve600is installed on the passage of the venting inducing frame300to thus intercept the direction in which the high-temperature and high-pressure gas and flames discharged from the first battery module are input to the second battery module, and open the direction in which they are discharged to the outside through the rupture portion500, and resultantly prevent the high-temperature and high-pressure gas and flames from flowing back into the battery pack.

In detail, as shown inFIG.3, the venting inducing frame300includes a pair of vertical beams310formed in parallel to a first direction and a pair of horizontal beams320formed in parallel to a second direction traversing the first direction, and as shown inFIG.4, the vertical beams310and the horizontal beams320respectively include covers311and321formed in the length direction of the vertical beams310and the horizontal beams320and passages312and322surrounded by the covers311and321to allow the gas to pass through, and at least one unidirectional valve600may be formed on the passages312and322.

As shown inFIG.11andFIG.12, a1-1passage (P1-1) and a1-2passage (P1-2) may be formed in a pair of vertical beams310, a2-1apassage (P2-1a) and a2-1bpassage (P2-1b) may be separately formed in one of the pair of horizontal beams320, and a2-2apassage (P2-2a) and a2-2bpassage (P2-2b) may be separately formed in the other of the pair of horizontal beams320.

Referring toFIG.3andFIG.4, a notch327is formed in the middle of the pair of horizontal beams320, and there is no passage on a portion where the notch327is formed, and it is found that the2-1apassage (P2-1a) and the2-1bpassage (P2-1b), and the2-2apassage (P2-2a) and the2-2bpassage (P2-2b), are separately formed on respective sides of the notch327. In this instance, the venting gate121may be connected to one of the passages formed on the respective sides of the notch327.

As shown inFIG.11andFIG.12, the1-1passage (P1-1), the2-1apassage (P2-1a), and the2-2apassage (P2-2a) are connected to each other, and the1-2passage (P1-2), the2-1bpassage (P2-1b), and the2-2bpassage (P2-2b) are connected to each other. The unidirectional valve600may be formed on one of the1-1passage (P1-1), the2-1apassage (P2-1a), and the2-2apassage (P2-2a) connected to each other, and on one of the1-2passage (P1-2), the2-1bpassage (P2-1b), and the2-2bpassage (P2-2b) connected to each other.

The rupture portion500may be formed on respective sides of one of the pair of horizontal beams320. In detail, the rupture portion500may be respectively connected to the2-1apassage (P2-1a) and the2-1bpassage (P2-1b).

As shown inFIG.11, the unidirectional valve600may be respectively formed on the2-1apassage (P2-1a) and the2-1bpassage (P2-1b), and the direction going to the rupture portion500from the venting gate121provided near the unidirectional valve600through the unidirectional valve600opens the passage, while the direction passing through the unidirectional valve600and going into the adjacent venting gate121may intercept the passage. By this, the phenomenon for the high-temperature and high-pressure gas and flames generated by one battery module100to flow back to another battery module may be prevented.

As shown inFIG.12, the unidirectional valve600may be respectively formed on the1-1passage (P1-1) and the1-2passage (P1-2), and the direction going to the rupture portion from the venting gate121connected to the2-2apassage (P2-2a) and the2-2bpassage (P2-2b) through the unidirectional valve600opens the passage, while the direction going to the venting gate121connected to the2-2apassage (P2-2a) and the2-2bpassage (P2-2b) through the unidirectional valve600may intercept the passage. By this, the phenomenon for the high-temperature and high-pressure gas and flames generated by one battery module100to flow back to another battery module may be prevented.

The above-described battery module and the battery pack including the same are applicable to various types of devices. The devices include transport means such as electric bicycles, electric vehicles, and hybrid vehicles, but the present invention is not limited thereto, and it may be applied to various devices that use the battery module and the battery pack including the same, which also belongs to the scope of the present invention.

DESCRIPTION OF SYMBOLS