Patent Description:
With the rapid increase in demand for portable electronic products, such as notebook computers, video cameras, portable phones, etc., and active development of electric vehicles, energy storage batteries, robots, satellites, etc. in recent years, studies on high performance secondary batteries capable of repetitive charging and discharging are being actively conducted.

Currently commercialized secondary batteries include nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, lithium secondary batteries, etc. and the lithium secondary batteries thereamong are receiving attention according advantages of free charging/discharging, a very low self-discharge rate, and high energy density since a memory effect is barely generated compared to nickel-based secondary batteries.

Such a lithium secondary battery mainly uses a lithium-based oxide and a carbon material respectively as a positive electrode active material and a negative electrode active material. The lithium secondary battery includes an electrode assembly, in which a positive electrode plate and a negative electrode plate on which the positive electrode active material and the negative electrode active material are respectively coated are arranged with a separator therebetween, and an exterior material, i.e., a battery case, sealing and accommodating the electrode assembly with an electrolyte solution.

Generally, the lithium secondary battery may be classified into a can-type secondary battery, in which the electrode assembly is embedded in a metal can, and a pouch-type secondary battery, in which the electrode assembly is embedded in a pouch of an aluminum laminate sheet, according to a shape of the exterior material.

Also, since various combustible materials are embedded in the lithium secondary battery, there is a risk of overheating, explosion, or the like due to over-charging, over-current, and other external physical impact, and thus there is a serious safety drawback. Moreover, the can-type secondary battery consisting of a rigid metal can has a higher risk of explosion.

Accordingly, in a battery module including a plurality of secondary batteries consisting of such a metal can, a configuration, such as a relay, a current sensor, a fuse, or a battery management system (BMS) may be used to safely and efficiently manage the secondary battery. Example of such a battery module can be found for instance in <CIT> or <CIT>.

However, despite such measures, a fire, such as an explosion of battery cells inside the battery module may occur due to an external impact, an abnormal operation of the battery cell, or a control failure by the BMS.

In this case, when one battery cell explodes among all battery cells mounted in the battery module, the heat such as flame generated due to the explosion may transfer to battery cells positioned nearby, thereby facilitating occurrence of a phenomenon in which the battery cells are continuously ignited, and thus a risk may be increased.

In this regard, a technology for increasing the stability of a battery module to solve such issues is required to be developed.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing a battery module capable of effectively preventing a secondary explosion of a cylindrical battery cell.

The present invention provides a battery module as defined by the independent claim <NUM>. Preferred embodiments are defined in the appended dependent claims.

In one aspect of the present disclosure, there is provided a battery module including: a plurality of cylindrical battery cells, each having at least two electrode terminals having different polarities formed at one end portion; an upper case including an accommodating portion where a space in which the plurality of cylindrical battery cells are inserted and accommodated is formed, a gas discharge path extending in front, back, left, and right directions to externally discharge a gas discharged from the plurality of cylindrical battery cells and where an open portion exposed downward is formed, and a gas discharge hole opened such that the gas discharge path is connected to the outside; a lower case including the accommodating portion combined to a bottom portion of the upper case and where a space in which the plurality of cylindrical battery cells are inserted and accommodated is formed, the gas discharge path extending in the front, back, left, and right directions to externally discharge the gas discharged from the plurality of cylindrical battery cells and where the open portion exposed upward is formed, and the gas discharge hole opened such that the gas discharge path is connected to the outside; and a cover sheet disposed between the upper case and the lower case to cover the open portion of the gas discharge path; and a plurality of wire type bus bars configured to electrically contact and connect the electrode terminals of the plurality of cylindrical battery cells to each other.

Also, the gas discharge hole may be formed in at least two of a front end, a rear end, a left end, and a right end of each of the upper case and the lower case.

Moreover, a height of the gas discharge path in an up-and-down direction may be at least <NUM>.

Also, the plurality of cylindrical battery cells may be spaced apart from each other by at least <NUM>.

In addition, the plurality of cylindrical battery cells may have a zigzag arrangement structure by being arranged in a line in a front-and-back direction and alternately biased in a forward direction or backward direction based on a reference line extending in a left-and-right direction.

Moreover, the gas discharge path may be straightly connected and extended in the front-and-back direction along an arrangement of the plurality of cylindrical battery cells and be connected and extended in zigzag in the front-and-back direction based on the reference line of the left-and-right direction.

Also, the accommodating portion may be adhesively formed to surround an outer surface of the plurality of cylindrical battery cells in a horizontal direction.

Also, a stopper protruding in a direction where the electrode terminals of the plurality of cylindrical battery cells are positioned to support at least one region of an upper surface or a lower surface of each of the plurality of cylindrical battery cells may be formed at the accommodating portion.

Moreover, a partition wall partitioning the plurality of cylindrical battery cells may be formed at the accommodating portion of each of the upper case and the lower case.

Also, a stepped structure having different heights of an outer surface in an up-and-down direction may be formed at the partition wall.

Further, the partition wall may have at least one inclined structure in which a vertical height continuously changes in a direction from one cylindrical battery cell to another cylindrical battery cell.

Also, an upper end portion of the partition wall may have a semicylindrical shape.

Moreover, a fixing groove having a structure recessed in an inward direction such that a part of each of the plurality of wire type bus bars is inserted may be formed in at least one of an upper end and a lower end of the partition wall.

Also, the battery module may further include a plurality of plate type bus bars electrically contacting and connected to the plurality of wire type bus bars and positioned at both sides of each of the upper case and the lower case in a left-and-right direction.

Further, an insertion groove recessed in an upward direction may be formed at each of both side portions of the upper case in the left-and-right direction such that at least one region of the plurality of plate type bus bars is inserted and accommodated therein, and an insertion groove recessed in a downward direction may be formed at each of both side portions of the lower case in the left-and-right direction such that at least one region of the plurality of plate type bus bars is inserted and accommodated therein.

Also, the cover sheet may include a mica material.

Moreover, an uplift structure protruding in an up-and-down direction along the gas discharge path may be formed at each of top and bottom surfaces of the cover sheet such that at least a portion of the uplift structure is inserted into an open portion of the gas discharge path.

In another aspect of the present disclosure, there is provided a battery pack including at least one battery module according to the present disclosure.

In another aspect of the present disclosure, there is provided a device including the battery pack of the present disclosure.

According to an aspect of the present disclosure, in a battery module, since a gas discharge path formed in an upper case and a lower case extends in front, back, left, and right directions, generated heat is prevented from being focused on a particular region as a gas or flame caused by an explosion of a cylindrical battery cell spreads in all directions. Accordingly, since the gas discharge path has a sufficient accommodation value for instantaneously accommodating the gas and flame, a secondary explosion of another cylindrical battery cell adjacent to an ignited cylindrical battery cell may be prevented.

Also, according to such an aspect of the present disclosure, in a battery module, since an accommodating portion of an upper case and a lower case are formed to surround an outer surface of a cylindrical battery cell, an outer surface of another cylindrical battery cell is prevented from directly contacting or being exposed to flame or the like of an ignited cylindrical battery cell, and thus a secondary ignition or explosion of a plurality of cylindrical battery cells may be prevented.

Moreover, according to an aspect of the present disclosure, by forming a gas discharge hole at an end portion of an upper case and a lower case in front, back, left, and right directions, the gas discharge hole is formed closely at any position of an accommodating portion of the upper case and the lower case, and thus a gas, flame, heat, or the like generated in a cylindrical battery cell may be quickly discharged. Accordingly, a risk of secondary explosion may be stably and greatly reduced.

Also, according to an aspect of the present disclosure, by disposing a cover sheet including a mica material between an upper case and a lower case, a short-circuit between a cylindrical battery cell positioned at the top of a battery module and a cylindrical battery cell positioned at the bottom of the battery module may be effectively prevented.

Moreover, according to an aspect of the present disclosure, since a wire type bus bar is capable of electrically connecting a plurality of cylindrical battery cells even via a small amount of materials, manufacturing costs may be reduced. Moreover, compared with a bar type bus bar, the wire type bus bar has small volume, and thus even when the wire type bus bar is positioned in a gas discharge path, an influence of disturbing a flow of discharged gas is small, thereby reducing a risk of secondary explosion or the like caused by a gas or flame.

Also, according to another aspect of the present disclosure, a partition wall formed in an accommodating portion of an upper case and a lower case may prevent movement (flow) of one end portion of a wire type bus bar such that, when the one end portion of the wire type bus bar is disconnected from an electrode terminal of a cylindrical battery cell, the one end portion of the wire type bus bar is prevented from being short-circuited with an electrode terminal of another cylindrical battery cell having a different polarity. Accordingly, the stability of a battery module of the present disclosure may be greatly increased.

<FIG> is a perspective view schematically showing a battery module according to an embodiment of the present disclosure. <FIG> is an exploded perspective view showing several isolated components with respect to a battery module according to an embodiment of the present disclosure. Also, <FIG> is a partial cross-sectional view schematically showing a partial internal structure of a cylindrical battery cell that is a partial component with respect to a battery module according to an embodiment of the present disclosure.

Referring to <FIG>, a battery module <NUM> according to an embodiment of the present disclosure may include a plurality of cylindrical battery cells <NUM>, an upper case 210A, a lower case 210B, a cover sheet <NUM>, and a plurality of wire type bus bars <NUM>.

Here, the cylindrical battery cell <NUM> may include a cylindrical battery can <NUM> and an electrode assembly <NUM> accommodated inside the battery can <NUM>.

Here, the battery can <NUM> may include a material having high electric conductivity, and for example, the battery can <NUM> may include an aluminum, steel, or copper material. Also, at least two electrode terminals <NUM> may be formed at the top of the battery can <NUM>.

In particular, the electrode terminal <NUM> may include a first electrode terminal 111A and a second electrode terminal 111B having different electric polarities. Also, when viewed from a direction indicated by an arrow F (shown in <FIG>), the first electrode terminal 111A may be formed at a circular top portion at the top of the battery can <NUM>. Also, the second electrode terminal 111B may be formed on a circular outer peripheral portion of the battery can <NUM>. In other words, the cylindrical battery cell <NUM> may include the at least two electrode terminals <NUM> having different polarities at one end portion thereof.

Meanwhile, unless specifically stated, top, bottom, front, back, left, and right directions in the present specification are based on the direction indicated by the arrow F.

Moreover, the electrode assembly <NUM> may have a structure in which a positive electrode and a negative electrode are wound in a jelly-roll shape with a separator therebetween. A positive electrode tab <NUM> is attached to the positive electrode (not shown) to contact the first electrode terminal 111A at the top of the battery can <NUM>. A negative electrode tab is attached to the negative electrode (not shown) to contact the second electrode terminal 111B at the bottom of the battery can <NUM>.

Referring back to <FIG>, in the cylindrical battery cell <NUM>, a top cap <NUM> is configured to form the electrode terminal <NUM> to protrude and such that at least a portion perforates when an internal gas reaches particular pressure or higher.

Also, the cylindrical battery cell <NUM> may include, at the bottom, a safety element <NUM> (for example, a positive temperature coefficient (PTC) element, a transparent conducting oxide (TCO), or the like) blocking a current by having a large battery resistance when a battery cell internal temperature is high. Also, the cylindrical battery cell <NUM> may include a safety vent <NUM> that has a downward protruding shape in a normal state but protrudes and ruptures when the battery cell internal temperature increases, thereby discharging a gas.

Moreover, the cylindrical battery cell <NUM> may include a current interrupt device (CID) <NUM> whose one top side region is combined to the safety vent <NUM> and one bottom side region is connected to a positive electrode of the electrode assembly <NUM>.

However, the battery module <NUM> according to the present disclosure may employ various cylindrical battery cells well-known at the time of application of the present disclosure, in addition to the cylindrical battery cell <NUM> described above.

<FIG> is a side view schematically showing an upper case that is a partial component with respect to a battery module according to an embodiment of the present disclosure. Also, <FIG> is a bottom view schematically showing upper components with respect to a battery module according to an embodiment of the present disclosure.

Referring to <FIG> and <FIG> together with <FIG> and <FIG>, the upper case 210A may include an accommodating portion <NUM> where a space in which the cylindrical battery cell <NUM> is inserted and accommodated is formed. Also, the upper case 210A may include an electric insulating material. For example, the electric insulating material may be a plastic material.

In particular, the accommodating portion <NUM> may include a cylindrical accommodating space in which the cylindrical battery cell <NUM> may be accommodated. Also, the cylindrical battery cell <NUM> may be accommodated inside the upper case 210A by being inserted into a circular opening O2 of the accommodating portion <NUM>.

Also, the accommodating portion <NUM> may be adhesively formed to surround an outer surface of the cylindrical battery cell <NUM> in a horizontal direction. In other words, the accommodating portion <NUM> may have an accommodating space adhered to the outer surface of the cylindrical battery cell <NUM> such that a particular material, flame, or the like is not introduced therein.

Here, the first electrode terminal 111A and the second electrode terminal 111B are positioned at a bottom portion of the cylindrical battery cell <NUM>. In other words, the cylindrical battery cell <NUM> may be inserted into the accommodating portion <NUM> of the upper case 210A upside down.

As such, according to such a configuration of the present disclosure, as in a result of Experiment Example <NUM> below, by forming the accommodating portion <NUM> of the upper case 210A to surround the outer surface of the cylindrical battery cell <NUM>, the other cylindrical battery cell <NUM> is prevented from directly contacting or being exposed to flame or the like of the ignited cylindrical battery cell <NUM> inside the battery module <NUM>, and thus a secondary ignition or explosion of the cylindrical battery cell <NUM> may be prevented.

Also, the plurality of cylindrical battery cells <NUM> may be accommodated in the accommodating portion <NUM> while being spaced apart from each other by, for example, at least <NUM>. However, the present disclosure is not necessarily limited to such a numerical value, and the numerical value is only an example.

As such, according to such a configuration of the present disclosure, as in an experiment result of Experiment Example <NUM> below, by positioning the plurality of cylindrical battery cells <NUM> accommodated in the battery module <NUM> according to an embodiment of the present disclosure to be spaced apart from each other by <NUM> or more, an amount of transferred heat is low when one cylindrical battery cell <NUM> is ignited, and thus a chain ignition of the adjacent cylindrical battery cells <NUM> may be prevented. However, when the plurality of cylindrical battery cells <NUM> are spaced apart from each other by less than <NUM>, when one cylindrical battery cell <NUM> is ignited, a chain ignition of the adjacent cylindrical battery cells <NUM> is highly likely to occur.

Also, a gas discharge path <NUM> extending in front, back, left, and right directions to externally discharge a gas discharged from the cylindrical battery cell <NUM> may be formed at the upper case 210A.

Thus, according to such a configuration of the present disclosure, by forming the gas discharge path <NUM> to extend in the front, back, left, and right directions, generated heat may be prevented from being focused on a particular region as a gas or flame caused by an explosion of the cylindrical battery cell <NUM> spreads in all directions. Also, since the gas discharge path <NUM> has a sufficient accommodation value for instantaneously accommodating the gas and flame, a secondary explosion of the other cylindrical battery cell <NUM> adjacent to the ignited cylindrical battery cell <NUM> may be prevented.

Also, a height H1 of <FIG> of the gas discharge path <NUM> in the up-and-down direction may be equal to or greater than <NUM>. However, when the height H1 of <FIG> of the gas discharge path <NUM> in the up-and-down direction is smaller than <NUM>, a chain ignition of the plurality of cylindrical battery cells <NUM> is likely to occur, and thus there is a risk.

As such, according to such a configuration of the present disclosure, as in a result of Experiment Example <NUM> below, when the height H1 of <FIG> of the gas discharge path <NUM> in the up-and-down direction is set to be equal to or greater than <NUM>, an effect of preventing a chain ignition of the concentrated cylindrical battery cells <NUM> may be achieved.

Moreover, the gas discharge path <NUM> may be formed at a bottom portion of the upper case 210A, which is adjacent to the first electrode terminal 111A formed at the bottom of the cylindrical battery cell <NUM>. Here, the safety vent <NUM> of <FIG> may be formed at the bottom portion of the cylindrical battery cell <NUM> where the first electrode terminal 111A is formed.

In addition, an open portion <NUM> exposed downward may be formed at the gas discharge path <NUM> of the upper case 210A. In other words, a side wall 212a capable of guiding movement of a gas may be formed at the gas discharge path <NUM>. The open portion <NUM> opened downward may be formed at the bottom of the side wall 212a.

Further, a gas discharge hole <NUM> opened such that the gas discharge path <NUM> is connected to the outside may be formed at the upper case 210A. In particular, the gas discharge hole <NUM> may be formed in at least two of a front end 210a, a rear end 210b, a left end 210c, and a right end 210d of the upper case 210A, when viewed from the direction indicated by the arrow F of <FIG>.

For example, as shown in <FIG>, the plurality of gas discharge holes <NUM> may be formed in each of the front end 210a, the rear end 210b, the left end 210c, and the right end 210d of the upper case 210A.

As such, according to such a configuration of the present disclosure, by forming the gas discharge hole <NUM> at end portions of the upper case 210A in the front, back, left, and right directions, a gas, flame, heat, or the like generated in the cylindrical battery cell <NUM> may be quickly discharged, and since the gas discharge hole <NUM> is formed close to any position of the accommodating portion <NUM> of the upper case 210A, a risk of secondary explosion may be stably and greatly reduced.

<FIG> is an exploded perspective view schematically showing lower components with respect to a battery module according to an embodiment of the present disclosure. Also, <FIG> is a side view schematically showing a lower case that is a partial component with respect to a battery module according to an embodiment of the present disclosure.

Referring to <FIG> and <FIG> together with <FIG> and <FIG>, the lower case 210B may have a coupling structure combined to the bottom of the upper case 210A. For example, the coupling structure may be a coupling structure in which a hook protrusion G1 and a coupling groove G2 are combined.

In particular, the hook protrusion G1 and the coupling groove G2 may be formed at each of the upper case 210A and the lower case 210B. For example, as shown in <FIG> and <FIG>, the hook protrusion G1 of the upper case 210A may be formed at corresponding position to be combined with the coupling groove G2 of the lower case 210B. Also, the hook protrusion G1 of the lower case 210B may be formed at a corresponding position to be combined with the coupling groove G2 of the upper case 210A.

Moreover, the lower case 210B may include the accommodating portion <NUM> where a space in which the cylindrical battery cell <NUM> is inserted and accommodated is formed. Also, the lower case 210B may include an electric insulating material. For example, the electric insulating material may be a plastic material.

In particular, the accommodating portion <NUM> may include a cylindrical accommodating space in which the cylindrical battery cell <NUM> may be accommodated. Also, the cylindrical battery cell <NUM> may be accommodated inside the lower case 210B by being inserted into the circular opening O2 of the accommodating portion <NUM>.

Here, the first electrode terminal 111A and the second electrode terminal 111B are positioned at the top portion of the cylindrical battery cell <NUM>. In other words, the cylindrical battery cell <NUM> may be inserted into the accommodating portion <NUM> of the lower case 210B while the first electrode terminal 111A and the second electrode terminal 111B are positioned at the top portion.

Also, the plurality of cylindrical battery cells <NUM> may be accommodated in the accommodating portion <NUM> while an outer surface of one cylindrical battery cell <NUM> and an outer surface of the other cylindrical battery cell <NUM> are spaced apart from each other by at least <NUM>.

As such, according to such a configuration of the present disclosure, as in the experiment result of Experiment Example <NUM>, since the plurality of cylindrical battery cells <NUM> accommodated in the battery module <NUM> are spaced apart from each other by <NUM> or more, an amount of transferred heat is low when one cylindrical battery cell <NUM> is ignited, and thus a chain ignition of the adjacent cylindrical battery cell <NUM> may be prevented.

Also, the accommodating portion <NUM> may be adhesively formed to surround the outer surface of the cylindrical battery cell <NUM> in the horizontal direction. In other words, the accommodating portion <NUM> may have an accommodating space adhered to the outer surface of the cylindrical battery cell <NUM> such that a particular material, flame, or the like is not introduced to the outer surface.

As such, according to such a configuration of the present disclosure, by forming the accommodating portion <NUM> of the lower case 210B to surround the outer surface of the cylindrical battery cell <NUM>, the other cylindrical battery cell <NUM> is prevented from directly contacting or being exposed to flame or the like of the ignited cylindrical battery cell <NUM> inside the battery module <NUM>, and thus a secondary ignition or explosion of the cylindrical battery cell <NUM> may be prevented.

<FIG> is a perspective view schematically showing partial components with respect to a battery module according to an embodiment of the present disclosure.

Referring to <FIG> together with <FIG>, the gas discharge path <NUM> extending in the front, back, left, and right directions to externally discharge the gas discharged from the cylindrical battery cell <NUM> may be formed at the lower case 210B.

As such, according to such a configuration of the present disclosure, by forming the gas discharge path <NUM> to extend in the front, back, left, and right directions, generated heat may be prevented from being focused on a particular region as a gas or flame caused by an explosion of the cylindrical battery cell <NUM> spreads in all directions. Also, since the gas discharge path <NUM> has a sufficient accommodation value for instantaneously accommodating the gas and flame, a secondary explosion of the other cylindrical battery cell <NUM> adjacent to the ignited cylindrical battery cell <NUM> may be prevented.

As such, according to such a configuration of the present disclosure, as in the result of Experiment Example <NUM> below, when the height H1 of <FIG> of the gas discharge path <NUM> in the up-and-down direction is set to be equal to or greater than <NUM>, an effect of preventing a chain ignition of the concentrated cylindrical battery cells <NUM> may be achieved.

Moreover, the gas discharge path <NUM> may be formed at a top portion of the lower case 210B, which is adjacent to the first electrode terminal 111A formed at the top of the cylindrical battery cell <NUM>. Here, the safety vent <NUM> of <FIG> may be formed at the top portion of the cylindrical battery cell <NUM> where the first electrode terminal 111A is formed.

In addition, the open portion <NUM> exposed upward may be formed at the gas discharge path <NUM> of the lower case 210B. In other words, the side wall 212a capable of guiding movement of a gas may be formed at the gas discharge path <NUM>. The open portion <NUM> opened upward may be formed at the top of the side wall 212a.

Further, the gas discharge hole <NUM> opened may be formed at the lower case 210B such that the gas discharge path <NUM> is connected to the outside. In particular, the gas discharge hole <NUM> may be formed in at least two of the front end 210a, the rear end 210b, the left end 210c, and the right end 210d of the lower case 210B. For example, as shown in <FIG>, the plurality of gas discharge holes <NUM> may be formed in each of the front end 210a, the rear end 210b, the left end 210c, and the right end 210d of the lower case 210B.

As such, according to such a configuration of the present disclosure, in the lower case 210B, by forming the gas discharge hole <NUM> in the front, back, left, and right directions, a gas, flame, heat, or the like generated in the cylindrical battery cell <NUM> may be quickly discharged, and since the gas discharge hole <NUM> is formed close to any position of the accommodating portion <NUM> of the lower case 210B, a risk of secondary explosion may be stably and greatly reduced.

<FIG> is a partial cross-sectional view schematically showing one region of a battery module taken along a line A-A' of <FIG>.

Referring to <FIG> together with <FIG> and <FIG> again, the cover sheet <NUM> may be disposed between the upper case 210A and the lower case 210B to cover the open portion <NUM> of the gas discharge path <NUM> of each of the upper case 210A and the lower case 210B.

Also, the cover sheet <NUM> may include a material having high fire resistance and electric insulation. For example, the cover sheet <NUM> may include a mica material and/or ceramic material. In particular, the cover sheet <NUM> may have a form in which a mica layer is formed on both surfaces of a ceramic sheet.

As such, according to such a configuration of the present disclosure, by disposing the cover sheet <NUM> having electric insulation between the upper case 210A and the lower case 210B, short-circuit between the cylindrical battery cell <NUM> located at the upper case 210A of the battery module <NUM> and the cylindrical battery cell <NUM> located at the lower case 210B may be effectively prevented.

Moreover, the cover sheet <NUM> including the mica material has excellent heat resistance, and thus may effectively reduce an effect of flame on the other adjacent cylindrical battery cell <NUM> caused by an explosion of the cylindrical battery cell <NUM>.

Referring to <FIG> together with <FIG> and <FIG> again, the wire type bus bar <NUM> may be configured to electrically contact and connect the electrode terminals <NUM> of the plurality of cylindrical battery cells <NUM> to each other, the plurality of cylindrical battery cells <NUM> being mounted on each of the upper case 210A and the lower case 210B.

In particular, the wire type bus bar <NUM> may include an electric conductive material. For example, the electric conductive material may be copper, aluminum, nickel, or the like. Also, the wire type bus bar <NUM> may contact and be combined to the outer surface of the first electrode terminal 111A of the cylindrical battery cell <NUM> and the outer surface of the second electrode terminal 111B of the other cylindrical battery cell <NUM>.

Alternatively, the wire type bus bar <NUM> may contact and be combined to the outer surface of the first electrode terminal 111A of the cylindrical battery cell <NUM> and the outer surface of the first electrode terminal 111A of the other cylindrical battery cell <NUM>.

Alternatively, the wire type bus bar <NUM> may contact and be combined to the outer surface of the second electrode terminal 111B of the cylindrical battery cell <NUM> and the outer surface of the second electrode terminal 111B of the other cylindrical battery cell <NUM>.

In other words, the wire type bus bar <NUM> may be configured to provide electrically serial or parallel connection between the plurality of cylindrical battery cells <NUM>.

Also, an end portion of the wire type bus bar <NUM> contacting the outer surface of the electrode terminal <NUM> may have a plate shape adhered to the outer surface of the electrode terminal <NUM>.

As such, according to such a configuration of the present disclosure, when the end portion of the wire type bus bar <NUM> is configured in the plate shape adhered to the electrode terminal <NUM>, a contact area with the electrode terminal <NUM> may be increased and adhesive force is also increased, and thus the durability of a connection structure may be effectively increased.

Also, the wire type bus bar <NUM> may be positioned inside the gas discharge path <NUM>. In other words, an electric connection structure of the plurality of cylindrical battery cells <NUM> through the plurality of wire type bus bars <NUM> may be formed inside the gas discharge path <NUM>.

For example, as shown in <FIG>, the plurality of wire type bus bars <NUM> formed at the upper case 210A may contact and connect the electrode terminal <NUM> of the cylindrical battery cell <NUM> and the electrode terminal <NUM> of the other cylindrical battery cell <NUM>. In other words, in the two cylindrical battery cells <NUM> arranged in the front-and-back direction, the second electrode terminals 111B thereof may be electrically connected through the wire type bus bar <NUM> to each other.

Also, in the plurality of cylindrical battery cells <NUM> arranged in the left-and-right direction, the first electrode terminal 111A and the second electrode terminal 111B may be electrically connected to each other through the wire type bus bar <NUM>.

For example, as shown in <FIG>, the plurality of wire type bus bars <NUM> formed at the lower case 210B may contact and connect the electrode terminal <NUM> of the one cylindrical battery cell <NUM> and the electrode terminal <NUM> of the other cylindrical battery cell <NUM>. In other words, in the two cylindrical battery cells <NUM> arranged in the front-and-back direction, the second electrode terminals 111B thereof may be electrically connected through the wire type bus bar <NUM>. Also, in the plurality of cylindrical battery cells <NUM> arranged in the left-and-right direction, the first electrode terminal 111A and the second electrode terminal 111B may be electrically connected to each other through the wire type bus bar <NUM>.

As such, according to such a configuration of the present disclosure, the wire type bus bar <NUM> may electrically connect the plurality of cylindrical battery cells <NUM> even with a small amount of materials, and thus manufacturing costs may be reduced. Moreover, compared with a bar type bus bar, the wire type bus bar has small volume, and thus even when the wire type bus bar <NUM> is positioned in the gas discharge path <NUM>, an influence of disturbing a flow of discharged gas is small, thereby reducing a risk of secondary explosion or the like caused by a gas or flame.

Also, the number of wire type bus bars <NUM> providing the electric connection between the two electrode terminals <NUM> may be set in consideration of a cross-sectional area of the wire type bus bar <NUM> and a required suitable level of resistance value.

In other words, when the area and the number of the wire type bus bars <NUM> providing the electric connection between the two electrode terminals <NUM> are increased, the resistance of electric flow between the two cylindrical battery cells <NUM> may be lowered. On the other hand, when the wire type bus bar <NUM> has high resistance, a heat value is high, thereby increasing the internal temperature of the battery module <NUM>, and thus the durability of the battery module <NUM> may be reduced or a fire may break out.

Also, when there are two or more wire type bus bars <NUM> providing the electric connection between the two electrode terminals <NUM>, even when one wire type bus bar <NUM> is disconnected, the remaining wire type bus bar <NUM> provides the electric connection, and thus damage caused by the disconnection may be reduced.

Referring back to <FIG> and <FIG>, the plurality of cylindrical battery cells <NUM> accommodated in the upper case 210A and the lower case 210B may have a zigzag arrangement structure by being arranged in a line in the front-and-back direction and alternately biased in a forward direction or backward direction based on a reference line extending in the left-and-right direction.

As such, according to such a configuration of the present disclosure, when the plurality of cylindrical battery cells <NUM> have the zigzag arrangement structure in the left-and-right direction, an empty space formed between the plurality of cylindrical battery cells <NUM> may be reduced, and accordingly, the more number of battery cells may be accommodated in the same volume, thereby effectively increasing the energy density of the battery module <NUM>.

Also, the gas discharge path <NUM> may be set according to an arrangement structure of the plurality of cylindrical battery cells <NUM>. In particular, the gas discharge path <NUM> may be straightly connected and extended in the front-and-back direction along an arrangement of the plurality of cylindrical battery cells <NUM>, and connected and extended in zigzag in the front-and-back direction based on the reference line of the left-and-right direction.

As such, according to such a configuration of the present disclosure, by connecting and extending the gas discharge path <NUM> in zigzag, flame generated in the cylindrical battery cell <NUM> may be interfered by the side wall 212a of the gas discharge path <NUM>, and thus an influence of the flame on the left and right cylindrical battery cells <NUM> adjacent to the ignited cylindrical battery cell <NUM> may be reduced.

<FIG> is a partial enlarged view schematically showing a region C' of <FIG>.

Referring to <FIG> and <FIG> together with <FIG>, a stopper <NUM> protruding in a direction where the electrode terminal <NUM> of the cylindrical battery cell <NUM> is positioned may be formed at the accommodating portion <NUM> of the upper case 210A and the lower case 210B. In particular, the stopper <NUM> may be configured to support at least one region of the upper surface or lower surface of the cylindrical battery cell <NUM>. In other words, the stopper <NUM> may be formed to support one end portion of the cylindrical battery cell <NUM> where the first electrode terminal 111A and the second electrode terminal 111B are formed.

For example, the stopper <NUM> may be configured to support the lower surface of the cylindrical battery cell <NUM> at the accommodating portion <NUM> formed at the upper case 210A. Also, the stopper <NUM> may be configured to support the upper surface of the cylindrical battery cell <NUM> at the accommodating portion <NUM> formed at the lower case 210B.

As shown in <FIG>, the plurality of stoppers <NUM> protruding to support one region of the second electrode terminal 111B of the cylindrical battery cell <NUM> may be formed at the accommodating portion <NUM> of the lower case 210B.

As such, according to such a configuration of the present disclosure, the plurality of stoppers <NUM> formed at the accommodating portion <NUM> may effectively prevent the cylindrical battery cell <NUM> from being displaced from the accommodating portion <NUM>.

Also, a space 217d to which the wire type bus bar <NUM> may extend may be formed between the plurality of stoppers <NUM>. In other words, the space 217d may be formed between a side surface of one stopper <NUM> in the horizontal direction and a side surface of the other stopper <NUM> in the horizontal direction.

As such, according to such a configuration of the present disclosure, even when the connection structure between the plurality of electrode terminals <NUM> of the wire type bus bar <NUM> is disconnected, the plurality of stoppers <NUM> may block the wire type bus bar <NUM> from being displaced from the space 217d. Accordingly, the durability of the battery module <NUM> may be effectively increased.

Referring to <FIG> together with <FIG> again, a partition wall <NUM> partitioning the plurality of cylindrical battery cells <NUM> may be formed at the accommodating portion <NUM> of each of the upper case 210A and the lower case 210B. Here, the partition wall <NUM> may protrude in an upward direction or a downward direction. Also, the partition wall <NUM> may have a stepped structure in which an outer surface of the partition wall <NUM> and an outer surface of the accommodating portion <NUM> have different heights in the top-and-bottom direction.

For example, as shown in <FIG>, the partition wall <NUM> may be formed between the two stoppers <NUM> formed at the accommodating portion <NUM> of the lower case 210B. Also, the partition wall <NUM> may have a quadrangular block shape protruding in the upward direction to have a stepped structure in which the height in the top-and-bottom direction is different from the outer surface of the accommodating portion <NUM>.

As such, according to such a configuration of the present disclosure, the partition wall <NUM> may block movement of one end portion of the wire type bus bar <NUM> to prevent the one end portion of the wire type bus bar <NUM> from being short-circuited with the electrode terminal <NUM> of the other cylindrical battery cell <NUM> of the different polarity, when the one end portion of the wire type bus bar <NUM> is disconnected from the electrode terminal <NUM> of the cylindrical battery cell <NUM>. Accordingly, the safety of the battery module <NUM> of the present disclosure may be greatly increased.

<FIG> is a partial enlarged view schematically showing partial components with respect to a battery module according to another embodiment of the present disclosure.

Referring to <FIG>, at least one inclined structure C1 in which a vertical height continuously changes in a direction from one cylindrical battery cell <NUM> to the other cylindrical battery cell <NUM> may be formed at a partition wall 219B.

In particular, the partition wall 219B may have the inclined structure C1 in which the height continuously increases and an inclined structure C2 in which the height continuously decreases in the direction from one cylindrical battery cell <NUM> to the other cylindrical battery cell <NUM>. In other words, the partition wall 219B may have the inclined structure C1 and the inclined structure C2, and the cross section of the partition wall 219B in the protruding direction of the partition wall 219B may have a triangular shape.

Also, an upper portion S1 of the partition wall 219B may have a semicylindrical shape.

For example, as shown in <FIG>, the partition wall 219B may have the two inclined structures C1 and C2 in which the height continuously changes in the direction from the one cylindrical battery cell <NUM> to the other cylindrical battery cell <NUM>, and the top portion S1 of the partition wall 219B may have a semicylindrical shape.

As such, according to such a configuration of the present disclosure, by forming the partition wall 219B to support the bottom of the wire type bus bar <NUM>, the partition wall 219B may guide the wire type bus bar <NUM> to be suitably arranged between the electrode terminal <NUM> of the cylindrical battery cell <NUM> and the electrode terminal <NUM> of the cylindrical battery cell <NUM>, and thus an electric connection process of the plurality of cylindrical battery cells <NUM> may be facilitated and a manufacturing time may be reduced.

Referring to <FIG>, a fixing groove G4 having a structure recessed in an inward direction may be formed on at least one of the top and the bottom of the partition wall <NUM>. The fixing groove G4 may be recessed in a size for accommodating the outer shape of the wire type bus bar <NUM> such that a portion of the wire type bus bar <NUM> is inserted.

For example, as shown in <FIG>, the fixing groove G4 recessed in a downward direction may be formed at the top of the partition wall <NUM>. Also, an insertion portion G4a into which the wire type bus bar <NUM> may be inserted may be formed at each of both sides inside the fixing groove G4.

As such, according to such a configuration of the present disclosure, by fixing the wire type bus bar <NUM> in the fixing groove G4 formed at the partition wall <NUM>, it is possible to prevent occurrence of short circuit, caused by the situation that one end portion of the wire type bus bar <NUM> may move and contact the other electrode terminal <NUM> when the wire type bus bar <NUM> is disconnected from the electrode terminal <NUM>.

Referring to <FIG> together with <FIG> and <FIG> again, a plurality of plate type bus bars <NUM> may electrically contact and be connected respectively to the plurality of wire type bus bars <NUM>. Also, the plate type bus bar <NUM> may eventually achieve electric connection to a module terminal <NUM> of <FIG> to be electrically connected to an external device. Accordingly, the plate type bus bar <NUM> may be configured to provide electric connection between the plurality of cylindrical battery cells <NUM> and the module terminal <NUM> of <FIG> inside the battery module <NUM>.

Here, the plate type bus bar <NUM> may include an electric conductive material. For example, the electric conductive material may be copper, aluminum, nickel, or the like.

Moreover, the plurality of plate type bus bars <NUM> may be positioned at both sides of each of the upper case 210A and the lower case 210B in the left-and-right direction. In particular, the plurality of plate type bus bars <NUM> positioned at both sides of each of the upper case 210A and the lower case 210B may have different polarities. For example, as shown in <FIG>, the electric polarity of the plate type bus bar <NUM> positioned at the left portion of the lower case 210B may be negative and the electric polarity of the plate type bus bar <NUM> positioned at the right portion may be positive.

Also, an insertion groove G3 recessed in an upward direction such that at least a region of the plate type bus bar <NUM> is inserted and accommodated therein may be formed at each of both side portions of the upper case 210A in the left-and-right direction. Moreover, the insertion groove G3 recessed in a downward direction such that at least a region of the plate type bus bar <NUM> is inserted and accommodated therein may be formed at each of both side portions of the lower case 210B in the left-and-right direction.

For example, as shown in <FIG> and <FIG>, the insertion groove G3 may be formed at each of both side portions of the upper case 210A, and the plate type bus bar <NUM> may be inserted and fixed to the insertion groove G3. Also, as shown in <FIG>, the insertion groove G3 may be formed at each of both side portions of the lower case 210B, and the plate type bus bar <NUM> may be inserted and fixed to the insertion groove G3.

<FIG> is a plan view schematically showing a battery module according to an embodiment of the present disclosure.

Referring to <FIG> together with <FIG> again, an upper support cover 250A where an accommodating space accommodating the top of the cylindrical battery cell <NUM> is formed may be combined to the top portion of the upper case 210A. In other words, the upper support cover 250A may include the accommodating space where a plurality of openings O1 perforated in circles are formed. Also, a support <NUM> supporting the upper surface of the cylindrical battery cell <NUM> may be formed at the top of the upper support cover 250A.

Moreover, a lower support cover 250B where an accommodating space accommodating the top of the cylindrical battery cell <NUM> is formed may be combined to the bottom portion of the lower case 210B. In other words, the lower support cover 250B may include the accommodating space where the plurality of openings O1 perforated in circles are formed. Also, the support <NUM> supporting the lower surface of the cylindrical battery cell <NUM> may be formed at the bottom of the lower support cover 250B.

For example, as shown in <FIG>, the upper support cover 250A and the lower support cover 250B are provided respectively at the top and the bottom of the battery module <NUM>. Also, the accommodating space for accommodating one region of the <NUM> cylindrical battery cells <NUM> may be provided at each of the upper support cover 250A and the lower support cover 250B. Also, the six supports <NUM> for supporting a cross section of the plurality of cylindrical battery cells <NUM> are provided at each of the upper support cover 250A and the lower support cover 250B.

<FIG> is a side view schematically showing a cover sheet that is a partial component with respect to a battery module according to another embodiment of the present disclosure.

Referring to <FIG> together with <FIG>, an uplift structure <NUM> protruding in the top-and-bottom direction may be formed at each of top and bottom surfaces of a cover sheet 230B. Also, the uplift structure <NUM> may be formed along the gas discharge path <NUM> such that at least a portion thereof is inserted into the open portion <NUM> of the gas discharge path <NUM>. Also, an uplifted size of the uplift structure <NUM> may protrude such as not to largely interfere with the movement of gas in the gas discharge path <NUM>. For example, as shown in <FIG>, the <NUM> uplift structures <NUM> protruding in the up-and-down direction may be formed at each of the top and bottom surfaces of the cover sheet 230B.

Meanwhile, a battery pack (not shown) according to the present disclosure may include at least one battery module <NUM> according to the present disclosure. Also, the battery pack according to the present disclosure may further include, in addition to the battery module <NUM>, a pack case for accommodating the battery module <NUM> and various devices for controlling charging and discharging of the battery module <NUM>, such as a battery management system (BMS), a current sensor, a fuse, etc..

Also, the battery pack according to the present disclosure may be applied to a device, such as an energy storage device. In other words, the device according to the present disclosure may include the battery pack according to the present disclosure.

For example, the battery pack may be applied to an energy storage system that may be used as a power source during emergency. In other words, the energy storage system according to the present disclosure may include the battery pack according to the present disclosure and a control unit capable of controlling the operation of the battery pack.

Hereinafter, examples and experiment examples are provided to describe the present disclosure in detail, but the present disclosure is not limited by these examples and experiment examples. The examples according to the present disclosure may be modified into various other forms, and the scope of the present disclosure should not be construed as being limited to the examples described below. The examples of the present disclosure are provided to enable one of ordinary skill in the art to more fully understand the present disclosure.

The cylindrical battery cell <NUM> was manufactured by manufacturing a top cap and cylindrical case are manufactured by using nickel (Ni)-plated steel plate cold deep drawn extra (SPCE), mounting an electrode assembly inside the cylindrical case, performing a beading process on a region of the cylindrical case corresponding to a top portion of the electrode assembly to form a crimping region, inserting a gasket to an inner surface of the crimping region, and combining the top cap to the top of the cylindrical case. Then, as shown in <FIG>, seven such cylindrical battery cells <NUM> were arranged such that side portions thereof in the horizontal direction contact each other without a space therebetween.

The seven cylindrical battery cells <NUM> were manufactured in the same manner as in Comparative Example <NUM>, except that the cylindrical battery cells <NUM> were spaced apart from each other by <NUM> in the horizontal direction.

Products obtained in Comparative Example <NUM> and Example <NUM> were respectively put into two housings, a center battery cell located at the center among seven battery cells of each of Comparative Example <NUM> and Example <NUM> was arbitrarily ignited, and then the housings were sealed. Then, it was checked whether a chain ignition occurs in the remaining battery cell adjacent to the center battery cell.

As experiment results, the chain ignition occurred in the remaining battery cell adjacent to the center battery cell in Comparative Example <NUM>, but the chain ignition did not occur in Example <NUM>. It is determined that the chain ignition did not occur in Example <NUM> because the remaining battery cells are spaced from the ignited center battery cell by <NUM> and thus the amount of heat transferred from the ignited battery cell to the remaining battery cell is low compared to Comparative Example <NUM>.

As shown in <FIG>, the seven cylindrical battery cells <NUM> manufactured in Comparative Example <NUM> were arranged to be spaced apart from each other by <NUM>, and an upper cover <NUM> adhesively surrounding the top of the cylindrical battery cell <NUM> was mounted on side portions of the seven cylindrical battery cells <NUM> in the horizontal direction such as to prevent flame from being introduced.

The seven cylindrical battery cells <NUM> were configured in the same manner as Example <NUM>, except that a separate member is not provided and the top portion of the cylindrical battery cells <NUM> in the horizontal direction is externally exposed.

As experiment results, the chain ignition occurred in the remaining battery cell adjacent to the center battery cell in Comparative Example <NUM>, but the chain ignition did not occur in Example <NUM>. It is determined that the chain ignition did not occur in Example <NUM> because radiant heat between the battery cells of Example <NUM> is low compared with Comparative Example <NUM> by reducing areas of the adjacent battery cells exposed to flame spread from the top of the ignited center battery cell, by using an upper cover.

As shown in <FIG>, in Comparative Example <NUM>, a module case <NUM> where the gas discharge path <NUM> and the accommodating portion <NUM> accommodating the seven cylindrical battery cells <NUM> therein are formed was prepared. Here, a vertical height H2 of the gas discharge path <NUM> of the module case <NUM> was set to <NUM>.

The module case <NUM> was prepared in the same manner as Comparative Example <NUM>, except that the vertical height H2 of the gas discharge path <NUM> was set to <NUM>.

A center battery cell located at the center among seven battery cells of each of Comparative Example <NUM> and Example <NUM> was arbitrarily ignited. Then, it was checked whether a chain ignition occurs in the remaining battery cell adjacent to the center battery cell.

As experiment results, the chain ignition occurred in the remaining battery cell adjacent to the center battery cell in Comparative Example <NUM>, but the chain ignition did not occur in Example <NUM>. It is determined that the chain ignition did not occur in Example <NUM> because, compared with Comparative Example <NUM>, a time of the adjacent battery cells being exposed to flame and a gas of high temperature spread from the ignited center battery cell is reduced by forming the gas discharge path <NUM> higher to increase the capacity of instantaneously accommodating the flame or gas, and heat transferred between the battery cells via convection is reduced.

Meanwhile, in the present specification, the terms indicating directions, such as up, down, left, right, front, and back, are used but it would be obvious to one of ordinary skill in the art that the terms are used only for convenience of description and may vary according to a position of a target object, a position of an observer, or the like.

Claim 1:
A battery module (<NUM>) comprising:
a first and a second plurality of cylindrical battery cells (<NUM>), each battery cell having at least two electrode terminals (<NUM>) having different polarities formed at one end portion of the battery cell;
an upper case (210A) having a bottom portion, the upper case comprising a first accommodating portion (<NUM>) where a space in which the first plurality of cylindrical battery cells are inserted and accommodated is formed, a first gas discharge path (<NUM>) formed at the bottom portion of the upper case and adjacent to electrode terminals of the first plurality of battery cells, the first gas discharge path extending in front, back, left, and right directions to externally discharge a gas discharged from the first plurality of cylindrical battery cells and where an open portion (<NUM>) exposed in a first direction is formed, and a first gas discharge hole (<NUM>) opened such that the first gas discharge path is connected to the outside;
a lower case (210B) having a top portion , combined to the bottom portion of the upper case, the lower case comprising a second accommodating portion where a space in which the second plurality of cylindrical battery cells are inserted and accommodated is formed, a second gas discharge path formed at the top portion of the lower case and adjacent to electrode terminals of the second plurality of battery cells, the second gas discharge path extending in the front, back, left, and right directions to externally discharge the gas discharged from the second plurality of cylindrical battery cells and where an open portion (<NUM>) exposed in a second direction opposite to the first direction is formed, and a second gas discharge hole (<NUM>) opened such that the second gas discharge path is connected to the outside; and
a cover sheet (<NUM>) disposed between the bottom portion of the upper case and the top portion of the lower case to cover the open portions of the first and the second gas discharge path; and
a plurality of wire type bus bars (<NUM>) configured to electrically contact and connect the electrode terminals of the first and the second plurality of cylindrical battery cells to each other.