BATTERY DEVICE

A battery device is disclosed. In some implementations, the battery device may include a cell stack in which a plurality of battery cells are stacked, and a case configured to accommodate the cell stack therein. At least one rupture portion, configured to be rupturable by internal pressure of the case, may be disposed on at least one surface of the case.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This patent document claims the priority and benefits of Korean Patent Application No. 10-2023-0065146 filed on May 19, 2023, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This disclosure relates to a battery device having high stability.

BACKGROUND

Unlike primary batteries, secondary batteries may be charged and discharged, and thus may be applied to devices within various fields such as digital cameras, mobile phones, laptops, and hybrid vehicles. Secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, lithium secondary batteries, and the like.

Among these secondary batteries, a large amount of research has been conducted on lithium secondary batteries having high energy density and discharge voltage. Recently, lithium secondary batteries have been manufactured as flexible pouch-type battery cells, and have been used in the form of a module or pack in which multiple battery cells are connected to each other.

However, in case that multiple battery cells are disposed to be adjacent to each other, when one battery cell ignites, flames may propagate to other adjacent battery cells, causing secondary ignition or explosion. Accordingly, there is a need for a battery device capable of suppressing the propagation of the above-described flames.

SUMMARY

According to an aspect of the present disclosure, it is possible to provide a battery device capable of rapidly discharging explosive by-products generated in the battery device due to ignition or explosion.

In some embodiments of the present disclosure, a battery device may include a cell stack in which a plurality of battery cells are stacked, and a case configured to accommodate the cell stack therein. A rupture portion, configured to be rupturable by internal pressure of the case, may be disposed on at least one surface of the case.

The rupture portion may have a rupture groove formed to be thinner than other portions of the rupture portion.

The battery device may further include a blade disposed on the at least one surface of the case, the blade configured to rupture the rupture portion.

The rupture portion may be configured to be deformed in shape by the internal pressure and to come into contact with the blade.

The case may include a rupture sheet including a first frame, and the rupture portion disposed in the first frame, and a cutter including a second frame, and the blade disposed in the second frame. The cutter may be disposed on the outside of the rupture sheet, and the blade may be disposed in a position corresponding to that of the rupture portion.

The blade includes a plurality of blades, and the plurality of blades may be disposed to correspond to one rupture portion.

The rupture portion may be deformed to have a hemispherical shape, and may protrude toward the cell stack. The rupture portion may protrude toward the blade and come into contact with the blade, when the internal pressure of the case increases.

At least a portion of an edge of the blade may be disposed to oppose a convex central portion of the rupture portion.

The rupture sheet may further include a protruding frame formed to protrude from the first frame. The rupture portion may be formed to extend from an end of the protruding frame.

The blade may be disposed to protrude from the second frame toward the rupture portion.

The blade may be disposed on the same plane as that of the second frame, and may be formed to have a sawtooth shape.

In some embodiments of the present disclosure, a battery device may include a cell stack in which a plurality of battery cells are stacked, and a case having an internal space in which the cell stack is accommodated. The case may include a rupture portion configured to be deformed by internal pressure of the case. At least a portion of the rupture portion may have a shape of a curved surface recessed toward the internal space of the case.

The battery device may further include a rupture sheet disposed on at least one side of the cell stack.

The rupture portion may be distributed throughout the rupture sheet.

The battery device may further include a blade configured to come into contact with a rupture portion as the rupture portion is deformed.

The rupture portion may be disposed between the blade and the cell stack.

When one battery cell explodes, a rupture portion of a battery device according to an embodiment of the present disclosure may be rapidly ruptured by internal pressure, such that explosion by-products may be externally discharged. Accordingly, additional effects from explosion may be minimized.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure in this patent document are described by example embodiments with reference to the accompanying drawings. Some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings, and a size of each component does not fully reflect an actual size.

The present disclosure can be implemented in some embodiments to provide a battery device.

FIG.1is a schematic perspective view of a battery device according to an embodiment of the disclosed technology, andFIGS.2and3are exploded perspective views of the battery device illustrated inFIG.1.

Referring toFIGS.1to3, a battery device1may include a cell stack20in which a plurality of secondary battery cells7are stacked, and a case30configured to accommodate the cell stack20therein. And a rupture portion43, configured to be rupturable by internal pressure of the case30, may be disposed on at least one surface of the case30.

The cell stack20in which a plurality of battery cells7are stacked may be formed to have a hexahedral shape, and a state in which the plurality of battery cells7are stacked may be fixed by a tape or bracket. In the present embodiment, the battery cells7may be stacked on each other in a thickness direction.

Each of the battery cells7may be a pouch-type secondary battery, and may have a structure in which electrode leads8are disposed to be oriented in opposite directions. The battery cell7, configured as described above, may be a secondary battery capable of being repeatedly charged and discharged, and may be a lithium (Li) battery or a nickel-hydrogen (Ni-MH) battery.

The battery cell7may be configured with an electrode assembly accommodated in a pouch-type cell case. In the present embodiment, the cell case may be formed by forming a single sheet of exterior material. More specifically, the cell case may be completed by forming one or two grooves in one exterior material, and then folding the exterior material such that the grooves form one space (hereinafter referred to as an accommodation portion). The accommodation portion may accommodate an electrode assembly and an electrolyte solution. The present disclosure is not limited to the above-described configuration, and the cell case may be formed by bonding two exterior materials to each other.

At least one barrier member60may be disposed between the battery cells7.

The barrier member60may be provided to prevent explosion by-products, such as flames or gas, from propagating to other surrounding battery cells7, when one battery cell7explodes. To this end, a plurality of barrier members60may be spaced apart from each other and interposed between the battery cells7, and ends of the barrier members60may be coupled to a bus bar assembly70. Accordingly, the battery cells7on opposite sides of one barrier member60may be spatially separated from each other. Thus, even when a battery cell7in one region explodes, an impact of the explosion on a battery cell7in another region may be minimized.

The barrier member60may include a material containing at least one of mica, metal, and resin. Here, the mica, metal, and resin may be materials, not easily melted by high-temperature flames, gas, or the like, and may be materials melting at 700° C. or higher.

For example, a metal material may be formed of iron (Fe), copper (Cu), or aluminum (Al), or a metal alloy, and may be thermally treated. In addition, flames retardant plastics, synthetic resin, may be used as a resin material. In addition, the mica, metal, and resin may be synthesized or mixed to form the barrier member60.

The bus bar assemblies70may be respectively disposed on side surfaces the battery cells7on which the electrode leads8are disposed, and may be coupled to the cell stack20, and each bus bar assembly70may include at least one bus bar77and an insulating frame71.

The insulating frame71may be formed of an insulating material, and may be formed to have a size corresponding to that of the entire side surface of the cell stack20which the bus bar assembly70opposes.

The insulating frame71may have a plurality of through-holes73into which the electrode leads8are inserted, and at least one bus bar77and a terminal11may be fixedly coupled to an external surface of the insulating frame71. Accordingly, the electrode leads8may pass through the through-hole73to be coupled to the bus bar77.

The bus bar77may be in the form of a conductive metal plate, and at least a portion may be buried in the insulating frame71or attached to the external surface of the insulating frame71. The battery cells7may be electrically connected to each other through the bus bar77. To this end, a plurality of through-slits78into which electrode leads8are inserted may be formed in the bus bar77, and the electrode leads8may be inserted into the through-slit78of the bus bar77and then bonded to the bus bar77using a method such as welding. Accordingly, at least a portion of an end of the electrode lead8may entirely pass through the bus bar77to be exposed to the outside of the bus bar77.

A plurality of bus bars77may be disposed to be spaced apart from each other in parallel in a direction in which the battery cells7are stacked, and at least two battery cells7may be coupled to one bus bar77.

A terminal11may be provided on at least one of the busbar assemblies70. The terminal11may be a conductive member electrically connected to the bus bar77and exposed to the outside of a case30of the battery device1. Accordingly, the terminal11may be physically/electrically connected to at least one of the bus bars77. For example, the terminal11may be formed integrally with one bus bar77. However, the present disclosure is not limited thereto, and the terminal11may be formed separately from the bus bar77and coupled to the insulating frame71, and then the bus bar77and the terminal11may be electrically connected to each other.

An external connection member55may be fastened to the terminal11. The external connection member55may connect one battery device1and a terminal11of another neighboring battery device1to each other.

The external connection member55may be fastened to the terminal11of the battery device1having different ends, using a fastening member such as a bolt.

When a plurality of battery devices1according to the present embodiment are used, respective battery devices1may be connected to each other in series or parallel through the external connection member55. In addition, among the battery devices1, some battery devices1may be connected to each other in series, and other battery devices1may be connected to each other in parallel, as necessary.

The external connection member55may be formed by processing a flat rod-shaped conductive member. In addition, the external connection member55may be formed of a flexible material. However, the present disclosure is not limited thereto, and a wire or cable may be used as the external connection member55.

The case30may have an internal space in which the cell stack20is accommodated. And the case30may include a rupture portion43configured to be deformed by internal pressure of the case30. At least a portion of the rupture portion43may have a shape of a curved surface recessed toward the internal space of the case30. The case30may define an exterior of the battery device1, and may be disposed on the outside of the cell stack20to protect the cell stack20from an external environment. At the same time, the case30according to the present embodiment may also be used as a heat dissipation member of the cell stack20.

The case30may be formed to entirely or partially surround the cell stack20. The case30may be formed of a metal material to ensure rigidity, but the present disclosure is not limited thereto. In addition, in order to increase a heat dissipation effect, at least a portion of the case30may be formed of aluminum.

In order to easily manufacture the battery device1, the case30may be divided into a plurality of cases. The case30according to the present embodiment may include a first case30acovering an upper portion of the cell stack20, a second case30bcovering a lower portion and a first side surface of the cell stack20, and a third case30ccovering a second side surface of the cell stack20.

FIG.4is an exploded perspective view of the first case illustrated inFIG.2.FIG.5is a partial cross-sectional view taken along line I-I′ ofFIG.1.

Referring toFIGS.4and5together, the first case30amay be formed to cover an entire upper surface of the cell stack20, and may include a rupture sheet40and a cutter50.

The rupture sheet40may include a first frame41, and at least one rupture portion43. The rupture sheet40may be disposed on at least one side of the cell stack20, and the rupture portion43may be distributed throughout the rupture sheet40.

The first frame41may be formed to be flat, and may form an overall exterior of the rupture sheet40, and the rupture portion43may be disposed in the first frame41. The rupture portion43may be configured to be preferentially ruptured when internal pressure of the battery device1increases. A plurality of rupture portions43may be distributed on the entire upper surface of the cell stack20, and may be formed of a material that is cuttable by a blade53to be described below of the cutter50during contact with the blade53, and may be formed to have a thickness that is cuttable by the blade53.

The rupture portion43may be configured to be deformed in shape by the internal pressure of case30and to come into contact with the blade53. Therefore, the rupture portion43may be disposed between the blade53and the cell stack20. In the present embodiment, the rupture portion43may be formed to convexly protrude from the first frame41toward the cell stack20. For example, each rupture portion43may be formed to have a hemispherical shape, and multiple rupture portions43may be disposed in the form of a lattice.

At least a portion of the rupture portion43may have a shape of a curved surface recessed toward an internal space of the case30. For example, the rupture portion43may protrude toward the cell stack20.

The first frame41and the rupture portion43may be integrally formed. For example, one sheet may be divided into the rupture portion43and the first frame41by a drawing process. In this case, the rupture portion43may be formed to be thinner than the first frame41. However, the present disclosure is not limited thereto, and the first frame41and the rupture portion43may be manufactured separately and coupled to each other, as necessary.

The rupture portion43according to the present embodiment may be formed of a metal thin film. For example, the rupture portion43may be formed of an aluminum thin film. However, the present disclosure is not limited thereto, and various materials that are easily rupturable by the blade53to be described below may be used.

The cutter50may be stacked on an upper portion of the rupture sheet40. For example, the cutter50may be disposed on the outside of the rupture sheet40.

The cutter50may include a second frame51, and at least one blade53disposed in the second frame51. The blade53may be disposed on the at least one surface of the case30, and the blade53is configured to rupture the rupture portion43. The blade53may be disposed in a position corresponding to that of the rupture portion43, and the blade43may be configured to come into contact with the rupture portion43as the rupture portion43is deformed. Accordingly, the number of blades53may be provided to be the same as the number of rupture portions43, and each blade53may be disposed to oppose a corresponding rupture portion43.

When gas is generated in the battery cell7and internal pressure of the battery device1increases, the rupture portion43may convexly protrude toward the blade53(in a direction of an arrow inFIG.5) due to an increase in the internal pressure. In such a process, the rupture portion43may come into contact with an edge of the blade53, and thus at least a portion of the rupture portion43may be cut by the blade53. In addition, gas or explosion by-products formed in the battery device1may be discharged to the outside of the battery device1through a gap formed by cutting the rupture portion43.

Accordingly, the edge of the blade53may be disposed to come into contact with the rupture portion43when the rupture portion43protrudes toward the blade53. For example, the edge of the blade53may be disposed to oppose the rupture portion43, and at least a portion of the edge of the blade53may be disposed to oppose a convex central portion (a most convex portion) of the rupture portion43. In order to increase contact reliability between the blade53and the rupture portion43, in the present embodiment, the edge of the blade53may be disposed to protrude toward the rupture portion43rather than the second frame51. For example, the blade53is disposed to protrude from the second frame51toward the rupture portion43. However, the present disclosure is not limited thereto.

In the present embodiment, the blade53may be formed to have a “+” shape. However, the present disclosure is not limited thereto, and the blade53may be modified into various forms capable of cutting or perforating the rupture portion43during contact with the rupture portion43, such as the blade53having a “−” shape or the blade53that is in the form of a sharp pin.

The blade53may be formed integrally with the second frame51, such that a movement thereof may be fixed. Accordingly, even when the blade53comes into contact with the rupture portion43, a movement thereof in a direction of being pressed by the rupture portion43may be suppressed.

The second frame51and the blade53may be integrally formed. For example, one sheet may be divided into the second frame51and the blade53by a drawing process. However, the present disclosure is not limited thereto, and the second frame51and the blade53may be manufactured separately and coupled to each other, as necessary.

The second case30bmay include a lower plate31covering a lower portion of the cell stack20, and a side plate32covering two first side surfaces, among side surfaces of the cell stack20. In the present embodiment, the battery cell7may include electrode leads8disposed in opposite directions. In the cell stack20, each battery cell7may include the electrode leads8disposed to be oriented toward the two first side surfaces. Accordingly, the side plate32may be disposed to oppose the electrode leads8of the battery cells7.

In the battery device1according to the present embodiment, the terminal11, electrically connected to the outside of the battery device1, may be disposed to protrude toward the outside of the side plate32. Accordingly, the side plate32may be understood as an element disposed on a surface of the case30on which the terminal11is disposed.

The lower plate31may extend from a lower end of the side plate32to a lower portion of the cell stack20to entirely or partially support a lower surface of the cell stack20.

In the present embodiment, the side plate32may be formed integrally with the lower plate31. For example, one sheet of metal plate may be bent and divided into the side plate32and the lower plate31. However, the present disclosure is not limited thereto, and the side plate32and the lower plate31may be provided separately and coupled to each other.

In addition, in the present embodiment, a case in which the entire second case30bis formed of the same material is described as an example, but the lower plate31and the side plate32may be formed of different materials, as necessary. For example, various modifications may be made as necessary, such as the lower plate31formed of aluminum and the side plate32formed of steel or stainless steel.

A bus bar cover90may be interposed between the second case30band the cell stack20.

The bus bar cover90may be formed of an insulating material such as insulating resin or mica, and may be disposed between the bus bar assembly70and the side plate of the second case30b. Accordingly, the bus bar cover90may be disposed such that one surface thereof opposes the bus bar assembly70and the other surface thereof oppose the side plate, and may be coupled to the bus bar assembly70in a form in which the bus bar cover90covers the entire bus bar77.

The bus bar cover90may be provided to ensure insulation between the bus bar77and the side plate. Accordingly, the bus bar cover90may have various forms capable of covering the entire bus bars77.

The third case30cmay cover side surfaces on which the electrode lead8is not disposed, among side surfaces of the battery device1, that is, opposite side surfaces on which the bus bar assembly70is not disposed. The third case30cmay be fixedly fastened to the first case30aand the second case30b.

The first case30a, the second case30b, and the third case30cmay be formed of a metal material, but the present disclosure is not limited thereto, and may be partially or entirely formed of an insulating material such as resin, as necessary. In addition, the first case30a, the second case30b, and the third case30cmay be coupled to each other using a method such as welding or the like. However, the present disclosure is not limited thereto, and various modifications may be made, such as coupling in a sliding manner or coupling using a fastening member such as a bolt or screw.

In the battery device according to the present embodiment described above, when the internal pressure of the battery device1increases due to an abnormality in the battery cell7, the rupture portion43may be ruptured and explosion by-products may be discharged to the outside of the battery device1. In this case, when one of multiple rupture portions43is ruptured, explosion by-products may be discharged through the corresponding rupture portion43and the internal pressure may decrease, such that the other rupture portions43may be maintained in an unruptured state. Accordingly, the explosion by-products, discharged to the outside of the battery device1, may be prevented from flowing into other battery cells7through the other rupture portions43.

The present disclosure is not limited to the above-described embodiments, and various modifications may be made.

FIG.6is a cross-sectional view of a battery device according to another embodiment of the present disclosure.

Referring toFIG.6, a rupture sheet40according to the present embodiment may include a rupture portion43disposed in a protruding frame42extending to one side of the rupture sheet40from a first frame41.

The protruding frame42may be formed to protrude from the first frame41by a certain length, and the rupture portion43may be formed to extend from an end of the protruding frame42.

When a protruding length of the rupture portion43is less than a protruding length of the protruding frame42, the entire rupture portion43may be disposed in an internal region of the protruding frame42. However, the present disclosure is not limited thereto.

FIG.7is a cross-sectional view of a battery device according to another embodiment of the present disclosure, andFIG.8is an exploded perspective view of the first case illustrated inFIG.7.

Referring toFIGS.7and8, In the present embodiment, the plurality of blades53are disposed to correspond to one rupture portion43. In addition, the rupture portion may be formed to have a shape of a groove having a rectangular entrance, rather than a hemispherical shape. However, a configuration in which the rupture portion43is convexly disposed toward a cell stack20and is convexly deformed toward the blade53by internal pressure of a battery cell may be the same as that of the above-described embodiment.

In the present embodiment, a case in which one rupture portion43is disposed to correspond to multiple blades53disposed in a row is described as an example, but the present disclosure is not limited thereto, and an arrangement structure or shape of the blades53corresponding to the one rupture portion43may be modified in various manners.

FIG.9is a cross-sectional view of a battery device according to another embodiment of the present disclosure.FIG.10is an exploded perspective view of the first case illustrated inFIG.9.

Referring toFIGS.9and10, in the battery device according to the present embodiment, an edge of a blade53may not be disposed to oppose a rupture portion43but may be disposed on the same plane as that of a second frame51.

In the present embodiment, the edge may be disposed to correspond to a peripheral portion of the rupture portion43rather than a central portion of the rupture portion43, and may be formed to have a sawtooth shape. Accordingly, when the rupture portion43outwardly protrudes, the sawtooth-shaped edge may come into contact with an edge of the rupture portion43to cut the rupture portion43.

In the battery device according to the present embodiment configured as described above, a blade53of a cutter50may be disposed within the thickness range of the second frame51, such that a thickness of the cutter50may be minimized, thereby reducing a thickness of the first case30aand an overall thickness of the battery device.

FIG.11is a cross-sectional view of a battery device according to another embodiment of the present disclosure.FIG.12is a perspective view of the first case illustrated inFIG.11.

Referring toFIGS.11and12, the battery device according to the present embodiment may include a rupture sheet40configured to be rupturable by internal pressure of the battery device.

The rupture sheet40may be ruptured by the internal pressure of the battery device without another component (for example, the cutter50ofFIGS.1to10) damaging the rupture sheet40itself. That is, the battery device according to the present embodiment may include only the rupture sheet40without the cutter50.

In the rupture sheet40according to the present embodiment, a rupture groove45may be formed in a rupture portion43. The rupture groove45of the rupture portion43may be formed to be thinner than other portions of the rupture portion43to induce rupture such that the rupture groove45of the rupture portion43is preferentially ruptured at a lower pressure. For example, the rupture groove45may be formed to have a thickness less than or equal to a half of that of the other portions of the rupture portion43. However, the present disclosure is not limited thereto.

The rupture groove45of the rupture sheet40may be damaged by the internal pressure of the battery device. For example, the internal pressure may directly damage and open the rupture groove45, formed to be thinner than the other portions of the rupture portion43. Alternatively, in the process of the rupture groove45being deformed due to the internal pressure, the rupture groove45, having rigidity lower than that of the other portions of the rupture portion43, may be damage and opened.

In the present embodiment, the rupture groove45may be formed to have a ‘+’ shape with respect to a convex central portion of the rupture portion43. However, the present disclosure is not limited thereto, and the rupture groove45may be formed to have various shapes as long as the rupture groove45may preferentially be ruptured by the internal pressure of the battery device.

The rupture sheet40according to the present embodiment may also be applied to the above-described embodiments including the cutter50.

Only specific examples of implementations of certain embodiments are described. Variations, improvements and enhancements of the disclosed embodiments and other embodiments may be made based on the disclosure of this patent document.

For example, in the above-described embodiments, a case in which a rupture portion is disposed on a portion of a case, disposed on an upper portion of a cell stack, is described as an example. However, the rupture portion may be disposed on a lower plate or a side plate, or the rupture portion may be disposed on various surfaces of the case, as necessary. In addition, respective embodiments may be implemented in combination with each other.