Patent Description:
The present disclosure relates to a battery module and a battery pack including the battery module, and more particular, to a battery module capable of preventing a flame generated at any one battery cell from spreading to other battery cells, and a battery pack including the battery module.

As technology development and demand for a mobile device have increased, demand for a secondary battery as an energy source has rapidly increased. Conventionally, a nickel-cadmium battery or a hydrogen ion battery has been used as the secondary battery. However, a lithium secondary battery is recently widely used because charging and discharging is free due to rare memory effect in comparison with a nickelbased secondary battery, a self-discharge rate is very low, and an energy density is high.

The lithium secondary battery mainly uses a lithium oxide and a carbonaceous material as a positive electrode active material and a negative electrode active material, respectively. The lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate, respectively coated with the positive electrode active material and the negative electrode active material, are arranged with a separator therebetween, and an outer member, that is a battery case, which seals and receives the electrode assembly together with an electrolyte solution.

The lithium secondary battery includes a positive electrode, a negative electrode, and a separator interposed therebetween and an electrolyte. Depending on which material is used for the positive electrode active material and the negative electrode active material, the lithium secondary battery is classified into a lithium ion battery (LIB) and a polymer lithium ion battery (PLIB). Generally, an electrode of the lithium secondary battery is prepared by applying the positive or negative electrode active material to a current collector made of aluminum or copper sheet, mesh, film, foil, or the like and then drying the same.

The lithium secondary battery is spotlighted due to its high operating voltage and very high energy density. However, since the lithium secondary battery uses an organic electrolyte, when being overcharged, the lithium secondary battery may cause overcurrent and overheating, which may lead to explosion or ignition in server cases.

Regarding the secondary battery, in case of a conventional battery module in which a plurality of battery cells are stacked, if any one battery cell explodes or ignites due to overcurrent and overheat, the flame spreads to other battery cells that operates normally, so that a plurality of battery cells explode in series. This may damage various devices equipped with the battery module, and a user may be exposed to the risk of a safety accident.

<CIT>, according to its Abstract, concerns a secondary battery module in which heat can be uniformly radiated with high efficiency and the temperature of a cell can be uniformly maintained. An NaS battery module includes a container, a plurality of cells for an NaS battery, sand, and a mica plate. The container includes a main body provided with side walls and a lower wall, and a cover provided with an upper wall. The side walls partition the inside and outside of the container in a direction in which the arrangement plane of the cells extends. The upper wall and the lower wall partition the inside and outside of the container in a direction perpendicular to the direction in which the arrangement plane of the cells extends. The lower wall and the side walls are high heat insulating walls whereas the upper wall is a solid low heat insulating wall having a heat insulating property lower than that of the high heat insulating wall. The cells, the sand, and the mica plate are housed inside of the container. A variable louver is disposed outside of the upper wall so as to cover the outer surface of the upper wall.

<CIT> discloses in its Abstract a cylindrical secondary battery module. The cylindrical secondary battery module includes: a plurality of cylindrical secondary battery cells respectively having a battery case in which an electrode assembly and an electrolyte are accommodated; a cell frame at which the plurality of cylindrical secondary battery cells are disposed; and a lid coupled to the cell frame and having a flame outlet. The cell frame includes: a plurality of plate members bent and coupled to intersect each other; and a space formed between the plurality of plate members so that the cylindrical secondary battery cells are disposed therein.

<CIT> concerns, according to its Abstract, an explosionproof and flame-retardant structure of a lithium battery comprising a shell and a surface cover, wherein accommodating cavities are formed in the shell, a plurality of lithium battery packs are arranged in the accommodating cavities and are connected with an electrode, the electrode is arranged on the surface cover, the explosionproof and flame-retardant structure is characterized in that fire extinguishing layers are arranged between the accommodating cavities and the lithium battery packs, each fire extinguishing layer comprises a low-melting-point isolation bag and a fluid flame retardant, and the fluid flame retardant is arranged in the low-melting-point isolation bag. The explosionproof and flame-retardant structure has the beneficial effects that <NUM>) the explosionproof and flame-retardant structure is simple and is low in production cost, and the market competitiveness is improved; <NUM>) the lithium battery is wrapped by fire extinguishing agents internally arranged in the low-melting-point isolation bags, the isolation bags are molten at a high temperature when the lithium battery is heated and combusted, so that effects of temperature reduction and electrolyte dilution can be achieved by the flame retardants in the isolation bags, the lithium battery is prevented from being on fire and combustion and even an explosion accident is prevented, and the application safety of the battery is improved; and <NUM>) with regard to batteries having different parameters, the positions and the numbers of the fire extinguishing layers can be correspondingly adjusted, and the explosionproof and flame-retardant structure is adaptive to different occasions to the greatest extent.

<CIT> pertains to a secondary battery provided to prevent ignition by absorbing generated heat as much as possible even in the case of heat generated due to misuses by nailing or crushing. This secondary battery comprises: an electrode assembly, and at least one safety element connected to the electrode assembly. The safety element comprises a safety layer comprising the material which absorbs heat by a short. The heatabsorbing material comprises polyethylene material. The polyethylene material is polyethylene wax. The safety layer comprises a conductive material arranged in the polyethylene wax. The safety element comprises a substrate layer, and a first adhesive layer for attaching safety element to the electrode assembly and substrate layer. The safety layer is interposed between the substrate layer and the first adhesive layer.

It is an object of the present disclosure to provide a battery module, which may prevent a flame generated at any one battery cell among a plurality of battery cells from spreading to other battery cells, and a battery pack including the battery module.

Also, a further object of the present disclosure is to provide a battery module, which may be easily manufactured due to a simple flame spread prevention structure, and a battery pack including the battery module.

In one aspect of the present disclosure, there is provided a battery module, comprising: a battery cell stack in which a plurality of battery cells are stacked; a flame spread prevention member configured to cover at least a portion of each battery cell; and a case configured to accommodate the battery cell stack covered by the flame spread prevention member. The battery cell is a pouch-type battery cell having a section of a rectangular shape, and the flame spread prevention member has a hexahedral shape. In addition a hollow is formed in the flame spread prevention member so that the battery cell is inserted into the frame spread prevention member. Also, the flame spread prevention member includes a mica plate containing mica with both heat insulation and heat resistance.

In addition, the battery module may further comprise a frame coupled to the case and having a plurality of insert grooves formed with a preset interval, wherein the flame spread prevention member may be slidably coupled to each of the insert grooves of the frame, and the battery cell may be interposed between the flame spread prevention members adjacent to each other.

Also, the frame may be provided in a pair, the pair of frames may be respectively coupled to an upper side and a lower side of the case so that the insert grooves thereof face each other, and both ends of the flame spread prevention member may be respectively inserted into the insert grooves of the pair of frames.

In addition, the frame may include a mica plate containing mica with both heat insulation and heat resistance.

Meanwhile, in another aspect of the present disclosure, there is also provided a battery pack, which comprises the battery module described above.

According to the embodiment of the present disclosure, since the flame spread prevention member covers the plurality of battery cells entirely, even though explosion or fire occurs at any one battery cell among the plurality of battery cells, it is possible to prevent the flame from spreading to other battery cells.

In addition, since a flame spread prevention member made of mica having both heat insulation and heat resistance properties is formed to simplify the flame spread prevention structure, the battery module may be manufactured easily.

In the drawings, the size of each element or a specific part of the element may be exaggerated, omitted, or schematically illustrated for convenience and clarity of a description. Thus, the size of each element does not entirely reflect the actual size of the element. A detailed description of well-known functions or elements associated with the present disclosure will be omitted if it unnecessarily obscures the subject matter of the present disclosure.

The term, 'combine' or 'connect' as used herein, may refer not only to a case where one member and another member are directly combined or directly connected but also a case where one member is indirectly combined with another member via a connecting member or is indirectly connected.

<FIG> is a cross-sectioned view showing a battery module according to the first embodiment of the present disclosure, <FIG> is a perspective view showing the battery module according to the first embodiment of the present disclosure, from which a flame spread prevention member and a battery cell are exploded, and <FIG> is a schematic perspective view showing the battery module according to the first embodiment of the present disclosure, in which an individual battery cell is covered by the flame spread prevention member.

Referring to <FIG>, a battery module <NUM> according to an embodiment of the present disclosure includes a battery cell stack <NUM>, a flame spread prevention member <NUM>, and a case <NUM>.

The battery cell stack <NUM> includes a plurality of stacked battery cells <NUM>. The battery cell <NUM> may have a structure in which a plurality of unit cells, in each of which a positive electrode plate, a separator and a negative electrode plate are arranged in order, or a plurality of bi-cells, in each of which a positive electrode plate, a separator, a negative electrode plate, a separator, a positive electrode plate, a separator and a negative electrode plate are arranged in order, are stacked suitable for a battery capacity. The battery cell <NUM> includes electrode leads <NUM>. The electrode leads <NUM> are a kind of terminal exposed to the outside and connected to an external device and are made of a conductive material. The electrode leads <NUM> include a positive electrode lead and a negative electrode lead. The positive electrode lead and the negative electrode lead may be disposed at opposite sides of the battery cell <NUM> in the longitudinal direction, or the positive electrode lead and the negative electrode lead may be disposed at the same side the battery cell <NUM> in the longitudinal direction.

The flame spread prevention member <NUM> individually coversthe plurality of battery cells <NUM>. Here, although the flame spread prevention member <NUM> contacts the battery cell <NUM> in order to cover the battery cell <NUM>, the flame spread prevention member <NUM> covers the battery cell <NUM> in a state of being spaced apart from the battery cell <NUM> by a predetermined interval. In this case, the flame spread prevention member <NUM> is supported by the case <NUM>. Meanwhile, in the first embodiment of the present disclosure, as shown in <FIG> and <FIG>, it is described that the flame spread prevention member <NUM> surrounds all side surfaces of the individual battery cell <NUM> except side surfaces where the electrode lead <NUM> is formed, namely all of four side surfaces of the battery cell <NUM> except the side surfaces where the electrode lead <NUM> is formed.

The flame spread prevention member <NUM> is provided as a mica plate containing mica with both heat insulation and heat resistance. In addition, as shown in <FIG>, the flame spread prevention member <NUM> is formed in a hexahedral shape in which four mica plates are coupled to form a hollow <NUM> therein. Here, the four mica plates may be integrally formed, or the four mica plates may be prepared separately and then coupled to each other. However, the number and shape of the mica plates are not limited to the above. The battery cell <NUM> is a pouch-type battery cell <NUM> having a section of a rectangular shape, and the flame spread prevention member <NUM> is formed in a hexahedral shape having a hollow <NUM> formed therein, and as shown in <FIG>, the pouch-type battery cell <NUM> is inserted into and placed in the hollow <NUM> of the flame spread prevention member <NUM>. Here, the flame spreading prevention member <NUM> is made of a mica with having heat insulation and heat resistance. Even if an explosion or ignition occurs in any one battery cell <NUM>, the flame is blocked by the mica plate and prevented from spreading to other battery cells <NUM>. That is, referring to <FIG>, since all of the plurality of battery cells <NUM> are individually covered by the flame spread prevention members <NUM>, respectively, even if an ignition occurs in any of the battery cells <NUM>, it is possible to prevent the flame from spreading, and so it is possible to prevent the flame from causing a larger fire. Meanwhile, the flame spread prevention member <NUM> is formed of a thin mica plate that is lighter than aluminum, which facilitates the fabrication and simplifies the structure.

The case <NUM> accommodates the battery cell stack <NUM> covered by the flame spread prevention member <NUM>. The case <NUM> surrounds the battery cells <NUM>, thereby protecting the battery cells <NUM> from external vibration or shock. The case <NUM> is formed in a shape corresponding to the shape of the battery cell stack <NUM>. For example, if the battery cell <NUM> or the battery cell stack <NUM> has a hexahedral shape with a section of a rectangular shape, the case <NUM> also has a hexahedron shape corresponding thereto. The case <NUM> can be manufactured, for example, by bending a plate made of metal, and thus the case <NUM> may be manufactured in an integrated form. If the case <NUM> is manufactured in an integrated form, the coupling process is simplified. Alternatively, the case <NUM> may be prepared as separated parts, which are coupled to each other by welding or the like.

Hereinafter, the operation and effect of the battery module <NUM> according to the first embodiment of the present disclosure will be described with reference to the drawings.

Referring to <FIG>, the battery cell <NUM> is formed in a substantially hexahedral shape, and the flame spread prevention member <NUM> formed of a mica plate is provided to surround four surfaces of the battery cell <NUM> except two surfaces where the electrode leads <NUM> are formed. That is, one flame spread prevention member <NUM> surrounds one of the plurality of battery cells <NUM>, and the plurality of flame spread prevention members <NUM> respectively cover the battery cells <NUM> in this manner. In addition, the battery cell stack <NUM> covered by the flame spread prevention members <NUM> is accommodated in the case <NUM>.

In this way, according to the embodiment of the present disclosure, since the flame spread prevention members <NUM> cover all of the plurality of battery cells <NUM>, respectively, even though explosion or ignition occurs in any one of the plurality of battery cells <NUM>, it is possible to prevent the flame from spreading to other battery cells <NUM>.

Meanwhile, a battery pack (not shown) according to an embodiment of the present disclosure, may include one or more battery modules <NUM> according to an embodiment of the present disclosure as described above. Also, in addition to the battery modules <NUM>, the battery pack (not shown) may further includes a housing for accommodating the battery modules <NUM>, and various devices for controlling charge and discharge of the battery modules <NUM>, such as a BMS, a current sensor, a fuse, and the like.

Claim 1:
A battery module (<NUM>), comprising:
a battery cell stack (<NUM>) in which a plurality of battery cells (<NUM>) are stacked;
a flame spread prevention member (<NUM>) configured to cover at least a portion of each battery cell (<NUM>); and
a case (<NUM>) configured to accommodate the battery cell stack (<NUM>) covered by the flame spread prevention member (<NUM>),
characterized in that the battery cell (<NUM>) is a pouch-type battery cell (<NUM>) having a section of a rectangular shape, and the flame spread prevention member (<NUM>) has a hexahedral shape;
wherein a hollow (<NUM>) is formed in the flame spread prevention member (<NUM>) so that the battery cell (<NUM>) is inserted into the flame spread prevention member (<NUM>),
wherein the flame spread prevention member (<NUM>) includes a mica plate containing mica with both heat insulation and heat resistance.