Patent Description:
Recently, due to fires or explosions that occur during the use of lithium secondary batteries, concerns are growing about the safety of battery use. For this reason, one of the major development tasks of lithium secondary batteries is to eliminate unsafe conditions such as fire and explosion caused by thermal runaway of battery cells. Battery packs are described in the following publilcations: <CIT>, <CIT>, <CIT>, <CIT>, <CIT> or <CIT>.

The disclosed technology can be implemented in some embodiments to prevent or mitigate thermal propagation in the specific battery module to other battery modules when a fire occurs in a specific battery module. The solution to the problem is defined in the appended claim <NUM> and its dependent claims.

The disclosed technology can be implemented in some embodiments to provide a battery pack with different thermal conductivity or thermal resistance values depending on the position.

The disclosed technology can be implemented in some embodiments to separate or remove only a specific battery module that has reached a certain temperature from the battery pack. The disclosed technology can be implemented in some embodiments to separate or remove a cell assembly provided inside the specific battery module.

The disclosed technology can be implemented in some embodiments to independently cool a plurality of battery modules.

The disclosed technology can be implemented in some embodiments to provide a battery pack structure applicable to a Cell To Pack (CTP) structure or a Cell To Chassis (CTC) structure.

The disclosed technology can be implemented in some embodiments to provide a structure of battery pack that exhibits an effect of mitigating or blocking thermal propagation (TP) between battery modules inside a battery pack. In particular, the disclosed technology discloses a structure changing a heat transfer path or increasing thermal resistance to prevent thermal propagation.

In some embodiments, a battery pack may include: one or more battery cells; one or more battery modules including a module case accommodating the one or more battery cells therein and a base panel forming a lower surface of the module case; and an accommodating panel forming a bottom surface of a module accommodating space for accommodating the one or more battery modules, wherein the accommodating panel includes: a first bottom surface positioned to face each of the base panels; and a second bottom surface including a heat resistance portion which is connected to at least a part of the first bottom surface and which prevents or mitigates conduction of heat generated from any one of the battery modules to another adjacent battery module through the first bottom surface.

In some implementations, the heat resistance portion may have a hole shape penetrating the second bottom surface.

In some implementations, the thickness of at least a part of the heat resistance portion may be smaller than the thickness of the first bottom surface.

In some implementations, the thermal conductivity of the heat resistance portion may be smaller than the thermal conductivity of the first bottom surface.

In some implementations, the thermal resistance portion may extend in a direction in parallel with any one of edges of the base panel.

In some implementations, when the temperature of the base panel reaches a temperature that is equal to or higher than a preset allowable temperature which is higher than room temperature, the tensile strength of the base panel may be lower than the tensile strength of the base panel at the room temperature.

In some implementations, when the temperature of the first bottom surface reaches a temperature that is equal to or higher than a preset deformation temperature which is higher than room temperature, the tensile strength of the first bottom surface may be lower than the tensile strength of the first bottom surface at the room temperature.

In some implementations, at the deformation temperature or higher, the shape of the accommodating panel may be deformed by the weight of the at least one battery module.

According to the invention, the battery pack further includes a comparting portion coupled to the accommodating panel to separate each of the one or more battery modules.

In some implementations, the heat resistance portion may be disposed below the comparting portion along an extending direction of the comparting portion.

In some implementations, at least a part of the heat resistance portion may be shieled by the comparting portion when the heat resistance portion is viewed from above the accommodating panel.

In some implementations, the module case may include a first flange portion and a second flange portion extending in a direction away from both sides of the module case, wherein, when the one or more battery modules are accommodated in the module accommodating space, the first flange portion and the second flange portion may be positioned above the comparting portion.

In some implementations, the module case may include: a first body including a first body first panel and a first body second panel extending in a direction away from the accommodating panel from the base panel and a pair of edges facing each other among edges of the base panel, respectively; and a second body including a second body first panel and a second body second panel extending toward the first body from a connecting panel facing the base panel and a pair of edges provided at positions corresponding to the first body first panel and the first body second panel among edges of the connecting panel, respectively, and being coupled with the first body.

In some implementations, the module case may further include: a first body first extension portion and a first body second extension portion bent from the first body first panel and the first body second panel, respectively, and extending in a direction away from the first body; a second body first extension portion and a second body second extension portion bent from the second body first panel and the second body second panel, respectively, and extending in a direction away from the first body; a first flange portion formed to be positioned so that the first body first extension portion and the second body first extension portion face each other when the first body and the second body are coupled; and a second flange portion formed to be positioned so that the first body second extension portion and the second body second extension portion face each other when the first body and the second body are coupled.

In some implementations, when the one or more battery modules are accommodated in the module accommodating space, the first flange portion and the second flange portion may be positioned above the comparting portion.

In some implementations, when the temperature of the base panel reaches a preset allowable temperature higher than room temperature, the tensile strength of the base panel may be lower than the tensile strength of the base panel at room temperature.

In some implementations, when the temperature of the first bottom surface reaches a preset deformation temperature higher than room temperature, the tensile strength of the first bottom surface may be lower than the tensile strength of the first bottom surface at room temperature.

In some implementations, each base panel of the one or more battery modules may be positioned separately from each other on the accommodating panel, and at least a part of the second bottom surface may be positioned between each base panel.

In some implementations, the battery pack may further include a plurality of cooling units each positioned below the one or more battery modules.

The second bottom surface may also be positioned between edges of each of the base panel and of the accommodating panel.

The disclosed technology can be implemented in some embodiments to prevent or mitigate thermal propagation in the specific battery module to other battery modules when a fire occurs in a specific battery module.

In some embodiments of the disclosed technology, thermal conductivity or thermal resistance values may be different depending on the position of the bottom surface of the battery pack.

The disclosed technology can be implemented in some embodiments to separate or remove only a specific battery module that has reached a certain temperature from the battery pack, or separate or remove a cell assembly provided inside the specific battery module.

The disclosed technology can be implemented in some embodiments to provide a structure of battery pack that is applicable to a Cell To Pack (CTP) structure or a Cell To Chassis (CTC) structure.

Hereinafter, some embodiments of the disclosed technology will be described in detail with reference to the attached drawings. The configuration or control method of the device described below will be discussed by way of example only.

Specific terms used in this specification are merely for convenience of explanation and are not used to limit the illustrated embodiments.

In some implementations, a battery pack may include a housing, and a module tray on a battery module is disposed and spaced apart from the housing, and a cooling unit for cooling the battery module by introducing a coolant between the housing and the module tray to remove heat generated by the battery module. In the event of occurrence of a fire in a specific battery module, it may be difficult to cool only the remaining battery modules excluding the specific battery module on fire, and it may be difficult to prevent or mitigate thermal propagation from the fire in the specific battery module to other adjacent battery modules.

To address these issues, the disclosed technology can be implemented in some embodiments to provide a battery pack for preventing or mitigating thermal propagation in a specific battery module to adjacent battery modules.

In some embodiments of the disclosed technology, the term "battery cell" may be used to indicate a basic unit of a lithium secondary battery, specifically a lithium-ion battery, which can be used by charging and discharging electrical energy. The main components of the battery cell are a cathode, an anode, a separator, and an electrolyte, and these main components are placed in a case (or pouch). The battery cell may further include tabs each connected to the cathode and the anode for electrical connection to the outside and protruding out of the pouch.

In some embodiments of the disclosed technology, the term "battery module" may be used to indicate a battery assembly in which one or more battery cells are grouped in one or more numbers and placed in a case to protect them from external shock, heat, vibration, or the like.

In some embodiments of the disclosed technology, the term "battery pack" may be used to indicate a set in which a preset number of the battery modules are gathered together to achieve a desired voltage or power.

<FIG> is an exploded diagram of a battery module. Referring to <FIG>, a battery module <NUM> may include one or more battery cells <NUM> and a bus bar assembly (not shown) electrically connected to the battery cells <NUM>. In some implementations, after the one or more battery cells <NUM> are stacked, they may be electrically integrated and connected by the bus bar assembly. This is referred to as a cell assembly <NUM>. The bus bar assembly may also perform a function of electrically connecting the cell assembly to an outside of the battery module.

The battery module <NUM> may further include a module case <NUM> (see <FIG>) forming a cell accommodation space <NUM> for accommodating the cell assembly <NUM>. The module case <NUM> may be provided to protect the cell assembly <NUM> from the outside.

The module case <NUM> may include: a first body <NUM> supporting one surface of the cell assembly <NUM>; and a second body <NUM> coupled with the first body <NUM>. The first body <NUM> may have a channel shape or U shape with an open top and with both sides open along the Y-direction. The second body <NUM> may be coupled with the first body <NUM> to close an open top of the first body <NUM>.

When the first body <NUM> and the second body <NUM> are coupled, the module case <NUM> may have a rectangular duct shape with both sides open along the Y-direction.

The module case <NUM> may further include a first cover <NUM> and a second cover <NUM> coupled with the both sides. The first cover <NUM> and the second cover <NUM> may include an insulating material.

Referring to <FIG>, the length of the battery cell <NUM> along a first direction, which is one of directions perpendicular to a height direction, may be longer than the length of the height direction (or a second direction) to improve safety of vehicles by lowering the center of gravity of a battery pack in vehicles that use the battery cell <NUM>. Such a rectangular-shaped battery cell may be referred to as a long cell.

A battery module <NUM> may further include a heat dissipating portion <NUM> disposed between the first body <NUM> and the cell assembly <NUM> in contact with the cell assembly <NUM>. The heat dissipating portion <NUM> may quickly discharge heat generated from the cell assembly <NUM> to the outside. For example, the heat dissipating portion <NUM> may be provided in the form of a heat dissipating pad or a thermal adhesive.

In some implementations, a battery cell <NUM> may be a pouch-type secondary battery (or battery cell), a prismatic secondary battery, or a cylindrical secondary battery. Although the drawings show a pouch-type battery cell as an example, the disclosed technology is not limited thereto.

<FIG> shows a cross-section cut along the X-direction of an example of the battery module <NUM>. Referring to <FIG>, the battery module <NUM> may include a module case <NUM> to form a cell accommodating space <NUM> for accommodating the cell assembly <NUM>. The module case <NUM> may include a first body <NUM> and a second body <NUM> coupled with the first body <NUM>.

The first body <NUM> includes a side that is open and may accommodate the cell assembly <NUM> through the open side. To this end, the first body <NUM> may include: a base panel <NUM> supporting the cell assembly <NUM>; and a first body first panel <NUM> and a first body second panel <NUM> which are bent and extend from both ends of the base panel <NUM> in the X-direction toward the open side. Accordingly, the first body <NUM> may be a U-shape or a channel shape with both sides open along the Y-direction.

The second body <NUM> (or module cover) may be coupled with the first body <NUM> to close the open surface of the first body <NUM>.

<FIG> shows a cross-section cut along the X-direction of another example of the battery module <NUM>. Unlike the battery module <NUM> shown in <FIG>, the battery module <NUM> may include a module case <NUM> forming a cell accommodating space <NUM> for accommodating a cell assembly <NUM>. Here, the module case <NUM> may include a first body <NUM> and a second body <NUM> coupled with the first body <NUM>.

A second body <NUM> in <FIG> may be considered as simply performing a cover role. That is, the height of the second body <NUM> may be equal to or greater than the height of the cell assembly <NUM>. On the other hand, the height of the first body <NUM> in <FIG> may be smaller than the height of the cell assembly <NUM>.

In addition, referring to <FIG>, the battery module <NUM> may include a first flange portion <NUM> and a second flange portion <NUM> extending outward from both sides along the X-direction of the module case.

The first flange portion <NUM> and the second flange portion <NUM> may configure the battery pack <NUM> (see <FIG>) to be supported by a comparting portion <NUM> (see <FIG>), which will be described later.

In some implementations, the first body <NUM> may include: a base panel <NUM> supporting the cell assembly <NUM>; and a first body first panel <NUM> and a first body second panel <NUM> each bent at both ends of the base panel <NUM> based on the X-direction and extending in the Z-direction, which is the height direction.

In addition, the first body <NUM> may further include: a first body first extending portion <NUM> bent at a free end of the first body first panel <NUM> and extending in a direction away from the first body <NUM>; and a first body second extending portion <NUM> bent at a free end of the first body second panel <NUM> and extending in a direction away from the first body <NUM>.

Likewise, the second body <NUM> may include: a connecting panel <NUM> disposed to face the base panel; and a second body first panel <NUM> and a second body second panel <NUM> each bent at both ends of the connecting panel <NUM> based on the X-direction and extending toward the first body <NUM>.

In addition, the second body <NUM> may further include: a second body first extending portion <NUM> bent at a free end of the second body first panel <NUM> and extending in a direction away from the second body <NUM>; and a second body second extending portion <NUM> bent at a free end of the second body second panel <NUM> and extending in a direction away from the second body <NUM>.

Therefore, the first flange portion <NUM> may formed by the first body first panel <NUM> and the second body first panel <NUM>, and the second flange portion <NUM> may be formed by the first body second panel <NUM> and the second body second panel <NUM>.

In addition, by coupling of the first body first panel <NUM> and the second body first panel <NUM> and coupling of the first body second panel <NUM> and the second body second panel <NUM>, coupling force between the first body <NUM> and the second body <NUM> may be increased.

In some implementations, the first flange portion <NUM> and the second flange portion <NUM> may be disposed on only one of the first body <NUM> and the second body <NUM>. For example, the first body <NUM> may include the base panel <NUM>, the first body first panel <NUM>, the first body second panel <NUM>, the first body first extending portion <NUM>, and the first body second extending portion <NUM>, while the second body <NUM> may include the connecting panel <NUM>, the second body first panel <NUM>, and the second body second panel <NUM>. In this case, the first flange portion <NUM> and the second flange portion <NUM> may be formed by the first body first extending portion <NUM> and the first body second extending portion <NUM>. However, in this case, the first flange portion <NUM> and the second flange portion <NUM> may couple the battery module <NUM> with a comparting portion <NUM>, as will be discussed below, and an additional function of strengthening a coupling force between the first body <NUM> and the second body <NUM> may not be performed.

<FIG> shows an example of a battery pack <NUM> implemented based on some embodiments of the disclosed technology. Referring to <FIG>, the battery pack <NUM> may include: a module accommodating space <NUM> in which one or more battery modules <NUM> are accommodated; and an accommodating panel <NUM> forming a bottom surface of the module accommodating space <NUM>.

The battery pack <NUM> may include an accommodating panel <NUM> forming a module accommodating space <NUM> accommodating the one or more battery modules <NUM>.

In addition, the battery pack <NUM> may further include an accommodating cover (not shown) coupled with the accommodating panel <NUM>.

Specifically, a bottom surface of the module accommodating space <NUM> may by formed by the accommodating panel <NUM>. And the battery pack <NUM> may further include frames <NUM>, <NUM>, <NUM>, <NUM> coupled with the accommodating panel <NUM> to form side surface of the module accommodating space <NUM>.

<FIG> shows an example of the accommodating panel <NUM> that has a rectangular shape. The shape of the accommodating panel <NUM> may vary depending on the position at which the battery pack <NUM> is to be mounted. Referring to <FIG>, the battery pack <NUM> may further include frames <NUM>, <NUM>, <NUM>, <NUM> extending along one edge among the edges of the accommodating panel <NUM>. For example, the battery pack <NUM> may further include a first connecting frame <NUM> and a second connecting frame <NUM> extending along the Y-direction and coupled to a part including two edges in parallel with the Y-direction among the edges of the accommodating panel <NUM>. In addition, the battery pack <NUM> may further include a first extending frame <NUM> and a second extending frame <NUM> extending along the X-direction and coupled with a part including two edges among the edges of the accommodating panel <NUM> to be connected with the first connecting frame <NUM> and the second connecting frame <NUM>, respectively.

The frames <NUM>, <NUM>, <NUM>, <NUM> may be others members coupled with the accommodating panel <NUM>, or may be members formed integrally with the accommodating panel <NUM>. That is, the frames <NUM>, <NUM>, <NUM>, <NUM> may be formed by being bent at the edgers of the accommodating panel <NUM>.

The battery pack <NUM> may accommodate one or more battery modules <NUM>. For example, all of the one or more battery modules <NUM> may be accommodated in one module accommodating space <NUM>. However, in some implementations, in consideration of the connection of wires of the one or more battery modules <NUM>, replacement of some battery modules, and safety, the one or more battery modules <NUM> are disposed at a predetermined spacing distance when positioned on the accommodating panel <NUM>.

To this end, the battery pack <NUM> may further include a comparting portion <NUM> to separate the module accommodating space <NUM>. Therefore, the comparting portion <NUM> may dispose the one or more battery modules <NUM> separately from each other in the module accommodating space <NUM>.

In some implementations, when the battery pack <NUM> includes the first flange portion <NUM> and the second flange portion <NUM>, the first flange portion <NUM> and the second flange portion <NUM> may be supported by the comparting portion <NUM>. That is, the first flange portion <NUM> and the second flange portion <NUM> may be located above the comparting portion <NUM>.

In addition, when there are two or more battery modules <NUM>, a first flange portion <NUM> of any one battery module <NUM> of the plurality of battery modules <NUM> and a second flange portion <NUM> of the other adjacent battery module <NUM> may be in contact with each other on the comparting portion <NUM>.

When the plurality of battery modules <NUM> are accommodated in the battery pack <NUM>, the comparting portion <NUM> may minimize distortion or deformation of the accommodating panel <NUM> caused by the weight of the battery module <NUM>.

Referring to <FIG>, it can be seen that the comparting portion <NUM> extends in the X-direction to be connected to the first connecting frame <NUM> and the second connecting frame <NUM> and comparts the module accommodating space <NUM> along the Y-direction.

For example, the comparting portion <NUM> may extend not only in the X-direction but also in the Y-direction to compart the interior of the battery pack <NUM>. That is, referring to <FIG>, the comparting portion <NUM> may be positioned between the plurality of battery modules <NUM> disposed in two rows along the Y-direction.

The comparting portion <NUM> may have a bar shape. In some implementations, to minimize twisting and bending, the inside of the comparting portion <NUM> may be a hollow shape. In this way, the polar moment of inertia and second moment of inertia of the comparting portion <NUM> may be increased.

In some implementations, the comparing portion <NUM> may be coupled with the accommodating panel <NUM>. The accommodating panel <NUM> may have a single plane shape and formed to have a predetermined thickness. In some implementations, the accommodating panel <NUM> may include a metal material in consideration of the weight of the battery module <NUM> disposed on the accommodating panel <NUM>.

However, when thermal runaway occurs in a specific battery module <NUM> among the plurality of battery modules <NUM>, the accommodating panel <NUM> may be a major passage for transferring heat of the battery module <NUM> where thermal runaway has occurred to other adjacently positioned battery modules.

In some implementations, a cooling unit or a fire extinguishing device is used to provide cooling or fire extinguishing operation, thus blocking thermal propagation between battery modules <NUM>. However, the disclosed technology can be implemented in some embodiments to change the thermal conductivity or thermal resistance values of the accommodating panel <NUM> of the battery pack <NUM> to provide a built-in mechanism in the construction of the accommodating panel <NUM> to reduce undesired thermal propagation between battery modules <NUM> supported by the accommodating panel <NUM>.

<FIG> schematically show the operating principle of preventing fire between the battery modules <NUM> by using the accommodating panel <NUM> having different thermal conductivity values or thermal resistance values at different positions or segments.

<FIG> shows a battery pack <NUM> including a plurality of battery modules <NUM> disposed on and supported by the accommodating panel <NUM>. The plurality of battery modules <NUM> may be spaced apart from one another by a predetermined spacing distance. In addition, the accommodating panel <NUM> may be made of a metal material to support the plurality of battery modules <NUM>.

When it is assumed that thermal runaway occurs in one or more battery cells <NUM> accommodated in a specific battery module <NUM> among the plurality of battery modules <NUM>, the temperature of the battery module <NUM> including the battery cell <NUM> where thermal runaway has occurred may also increase. In severe cases, not only an increase of temperature but also smoke and fire may occur due to the thermal runaway.

For different battery modules <NUM>, the temperature increase occurring in any one battery module may be transferred to an adjacent battery module in the form of transfer of heat. The form of heat transfer may occur via one or more of thermal conduction, thermal convection, and/or thermal radiation. In implementations where the material of the accommodating panel <NUM> is a metal, the main passage and form of heat transfer between battery modules <NUM> may be thermal conduction through the accommodating panel <NUM> because a metal is usually a thermal conducting material due to the relatively high thermal conductivity of the metal.

Therefore, changing the thermal resistance value or thermal conductivity of the major passage of heat transfer in the accommodating panel <NUM> at different locations or segments can interrupt the thermal conduction to reduce or minimize the amount of heat being conducted via the accommodating panel <NUM>. As a result, the transfer of heat from a battery module <NUM> where thermal runaway has occurred to other adjacent battery modules may be reduced, minimized, or prevented.

When heat from the battery module <NUM> where thermal runaway has occurred is not transferred to other battery modules, heat may continue to accumulate in an area where the battery module <NUM> (the battery module where thermal runaway has occurred) is positioned. Accordingly, the temperature of the battery module <NUM> where thermal runaway has occurred and an area of the accommodating panel <NUM> supporting the battery module <NUM> where thermal runaway has occurred may increase. Referring to <FIG>, considering that the module case <NUM> and the accommodating panel <NUM> include a metal, when the increased temperature becomes higher than a certain temperature, a part of the accommodating panel <NUM> may be deformed or even melted, the battery module <NUM> in which thermal runaway has occurred may fall in the direction of the gravity due to its own weight and be dropped from the battery pack <NUM>. Alternatively, a lower surface of the battery module <NUM> where thermal runaway has occurred may be deformed or melted, and a cell assembly <NUM> where thermal runaway has occurred, which is positioned inside the module case <NUM>, may be separated and fall apart. <FIG> uses an arrow to indicate that a part of the accommodating panel <NUM> is melted away at a particular location where an accommodating panel through-hole <NUM> is formed, and the battery module <NUM> where thermal runaway has occurred falls down due to its own weight through the accommodating panel through-hole <NUM>.

<FIG> shows an example of the accommodating panel <NUM> that implements different portions or segments with different thermal conductivity values or thermal resistance values to cause spatial disruption of thermal conduction based on one implementation of the disclosed technology.

In order for the accommodating panel <NUM> to have different thermal conductivity values or thermal resistance values depending on the position, the accommodating panel <NUM> may include: a first bottom surface <NUM> where the battery module <NUM> is positioned; and a second bottom surface <NUM> connected to at least a part of the first bottom surface <NUM> and including a thermal resistance portion (3092a, see <FIG>) which blocks conduction of heat generated from the battery module <NUM> through the first bottom surface <NUM> or which has a different thermal conductivity from the first bottom surface <NUM>.

In some implementations, the thermal resistance portion 3092a may be disposed at the bottom of the comparting portion <NUM> along an extending direction of the comparting portion <NUM>. This is because the first bottom surface <NUM> may support the battery module <NUM>, while the second bottom surface <NUM> may be positioned between the battery modules <NUM>, and the comparting portion <NUM> may also be positioned along the bottom surface <NUM>.

Therefore, at least a part of the thermal resistance portion 3092a may be shielded by the comparting portion <NUM> when the thermal resistance portion 3092a is viewed from above the accommodating panel <NUM>. That is, only after separating the comparting portion <NUM> from the accommodating panel <NUM>, the heat resistance portion 3092a may be exposed to the outside when the thermal resistance portion 3092a is viewed from above the accommodating panel <NUM>.

According to the invention, the comparting portion <NUM> is an angulated U-shaped frame open toward the second bottom surface. Therefore, when the comparting portion <NUM> is coupled with the accommodating panel <NUM>, the interior of the comparting portion and the accommodating panel <NUM> may form an empty space, increasing the polar moment of inertia and second moment of inertia of the comparting portion <NUM>. In other words, this is because a hollow member is more resistant to twisting and deformation than a solid member.

<FIG> shows an enlarged example of the comparting portion <NUM> and the second bottom surface <NUM>. <FIG> shows a cross-section of the battery module <NUM>, the comparting portion <NUM>, the first bottom surface <NUM>, and the second bottom surface <NUM>. <FIG> shows an example of the second bottom surface <NUM>. <FIG> shows another example of the second bottom surface <NUM>.

Referring to <FIG> and <FIG>, two or more battery modules <NUM> may be provided and may be adjacent to each other but separated by the comparting portion <NUM>.

As shown in <FIG>, when the battery module <NUM> is provided with a first flange portion <NUM> and a second flange portion <NUM> extending in a direction away from the module case <NUM>, as shown in <FIG>, a second flange portion <NUM> of any one battery module <NUM> and a first flange portion <NUM> of the other adjacent battery module <NUM> may be positioned on the comparting portion <NUM> and come into contact with each other.

In some implementations, the second flange portion <NUM> of any one battery module <NUM> and the first flange portion <NUM> of the other adjacent battery module <NUM> may be positioned apart from each other without contacting each other.

The second flange portion <NUM> of any one battery module <NUM> may be formed by coupling a first body second extension portion <NUM> and a second body second extension portion <NUM> with each other when the first body <NUM> and the second body <NUM> are coupled, and the first flange portion <NUM> of the other adjacent battery module <NUM> may be formed by coupling a first body first extension portion <NUM> and a second body first extension portion <NUM> when the first body <NUM> and the second body <NUM> are coupled.

Referring to <FIG> and <FIG>, a part of the accommodating panel <NUM> where a base panel <NUM> of the battery module is in contact with the accommodating panel may form the first bottom surface <NUM>. The second bottom surface <NUM> may be positioned between the base panels <NUM> (see <FIG>).

If a battery module <NUM> does not have the first flange portion <NUM> and the second flange portion <NUM>, the first bottom surface <NUM> is an area where the battery module <NUM> is positioned, and the second bottom surface <NUM> may be positioned in an area positioned between the battery modules <NUM> to connect the first bottom surface <NUM>.

Referring to <FIG>, the height L1 from the accommodating panel <NUM> to the upper surface of the comparting portion <NUM> may be the same as the height L2 from the accommodating panel <NUM> to the first flange portion <NUM> and a lower surface of the second flange portion <NUM>. Therefore, the base panel <NUM> may be in contact with the first bottom surface <NUM> to be supported by the first bottom surface.

If the battery module <NUM> is only one battery module, the battery pack <NUM> may not include the comparting portion <NUM>. In this case, the second bottom surface <NUM> may be positioned between the first bottom surface <NUM> and an edge of the accommodating panel <NUM>.

In some implementations, referring to <FIG>, the battery pack <NUM> may further include a cooling unit <NUM> positioned below the battery module <NUM> to cool the battery module <NUM>. For independent cooling of each battery module <NUM>, when there are two or more battery modules <NUM>, two or more cooling units <NUM> may also be provided and positioned below each of the plurality of battery modules <NUM>. In addition, the plurality of cooling units <NUM> may each operate independently. When thermal runaway occurs in any one of the plurality of battery modules <NUM>, this is to separate only the battery module <NUM> where thermal runaway has occurred from the battery pack <NUM>.

In a case where the plurality of cooling units <NUM> is independently provided, inlets and outlets of the plurality of cooling units <NUM> are connected in series rather than in parallel. That is, even when the cooling unit fails to operate due to thermal runaway in any one battery module <NUM>, the other cooling units may normally supply and circulate a coolant.

<FIG> shows an example in which the cooling units <NUM> are positioned with the first bottom surface <NUM> therebetween. The battery module <NUM> may be positioned above the first bottom surface <NUM>, and the cooling unit <NUM> may be positioned below the first bottom surface <NUM>. Since the material of the first bottom surface <NUM> is a metal, for example, an aluminum metal material, even when the cooling unit <NUM> is spaced apart from the battery module <NUM>, smooth cooling may be achieved through the first bottom surface <NUM>.

In some implementations, in order for the thermal resistance value or thermal conductivity of the second bottom surface <NUM> to be different from the first bottom surface <NUM>, the area through which heat is conducted is reduced or the thickness through which heat is conducted is reduced. In some implementations, the material of the second bottom surface <NUM> is different from the material of the first bottom surface <NUM>.

To separate only the battery module <NUM> where thermal runaway has occurred, the second bottom surface <NUM> may include a thermal resistance portion 3092a having a different thermal conductivity or thermal resistance value.

<FIG> shows an example in which the thermal resistance portion 3092a is in the form of a hole formed through the second bottom surface <NUM>. Since heat may not be conducted through the hole-shaped thermal resistance portion 3092a, the thermal conductivity at the first bottom surface <NUM> and the thermal conductivity at the second bottom surface <NUM> may be different due to the area difference, and the second bottom surface <NUM> will have a greater thermal resistance value.

Therefore, heat of the battery module <NUM> where thermal runaway has occurred may not be dissipated to other adjacent battery modules <NUM> through the second bottom surface <NUM> but may continue to accumulate. In other words, only the first bottom surface <NUM> supporting the battery module <NUM> where thermal runaway has occurred will exhibit a faster temperature increase than other areas of the accommodating panel <NUM>.

Referring to <FIG>, the thermal resistance portion 3092a may be provided in the form of a groove. The second bottom surface <NUM> may include a first connecting portion 3092b and a second connecting portion 3092c connecting the heat resistance portion 3092a and one side of the heat resistance portion 3092a to the first bottom surface <NUM>.

The thickness of at least a part of the thermal resistance portion 3092a may be smaller than the thickness of the first bottom surface <NUM>. Since the thickness is small, the thermal conductivity of the thermal resistance portion 3092a may be smaller than that of the first bottom surface <NUM>, and the thermal resistance value may be greater.

In addition, referring to <FIG>, the thermal resistance portion 3092a may include a material different from that of the first bottom surface. In addition, the material of the thermal resistance portion 3092a may be different from the material of the first connecting portion 3092b and the second connecting portion 3092c. Therefore, even when the thickness of the first bottom surface <NUM> and the second bottom surface <NUM> are the same, the thermal conductivity of the thermal resistance portion 3092a may be less than the thermal conductivity of the first bottom surface <NUM>.

Referring to <FIG>, a hole shape of the thermal resistance portion 3092a may extend in parallel with one side surface of the battery module <NUM>. In addition, there may be a plurality of holes arranged continually rather than in the form of one large hole. Since the thermal resistance portion 3092a is formed to prevent the heat of a battery module <NUM> where thermal runaway has occurred from being conducted to another adjacent battery module <NUM> through the second bottom surface <NUM>, the thermal resistance portion 3092a may have any shape as long as the thermal conductivity or thermal resistance value is different.

Likewise, a groove-shaped thermal resistance portion 3092a illustrated in <FIG> or a thermal resistance portion 3092a made of another material may also be provided as a single element or item extending in parallel with one side surface of the battery module, or may also be provided as a plurality of elements or items.

In one example, the thermal resistance portion 3092a may have a single groove extending in parallel with one side surface of the battery module <NUM>. In another example, the thermal resistance portion 3092a may have a plurality of grooves extending in parallel with one side surface of the battery module <NUM>.

In some implementations, even if the thermal resistance portion 3092a is made of a different material, the portions including different materials are not integrated into one part, but it may discontinuously extend in parallel with one side surface of the battery module <NUM>.

<FIG> shows a cross-section of the battery module <NUM> and a compartment <NUM> adjacent to the battery module <NUM>. <FIG> shows an example of the battery module <NUM> being separated.

Assuming a case where thermal runaway occurs in a specific battery cell of the cell assembly <NUM>, thermal runaway of the battery cell <NUM> will propagate to adjacent battery cells. Accordingly, heat of the battery module <NUM> accommodating the cell assembly <NUM> will transfer or propagate to other adjacent battery modules <NUM>. The main passage and form of this heat transfer may be thermal conduction through specific areas (CH1, CH2) of an accommodating panel.

In the disclosed technology, in order to block or delay the propagation of heat, the battery module <NUM> which exhibits a rapid temperature increase due to thermal runaway is separated from the battery pack <NUM>.

To this end, as shown in <FIG>, the battery module <NUM> is separated from the accommodating panel <NUM>. In addition, <FIG> shows another example in which the cell assembly <NUM> is separated from the module case <NUM> and the accommodating panel <NUM>.

The example in <FIG> is an example for which a case where the battery module <NUM> does not have a first flange portion <NUM> and a second flange portion <NUM> is assumed. On the other hand, <FIG> illustrates an example where a first flange portion <NUM> and a second flange portion <NUM> are supported by the comparting portion <NUM>.

When transfer of heat through the accommodating panel <NUM> begins to be blocked or mitigated by the thermal resistance portion 3092a, the temperature of a first bottom surface <NUM> supporting a battery module <NUM> where thermal runaway has occurred will increase faster than that of other positions of the accommodating panel <NUM>.

Therefore, when the temperature of a first bottom surface <NUM> supporting a battery module <NUM> where thermal runaway has occurred reaches a preset deformation temperature higher than room temperature, the first bottom surface <NUM> may be deformed or melted earlier than other positions of the accommodating panel <NUM>.

When the temperature reaches the deformation temperature or higher, the tensile strength of the first bottom surface <NUM> may be lower than the tensile strength of the first bottom surface <NUM> at room temperature.

In addition, above the deformation temperature, as at least a part of the first bottom surface <NUM> is deformed, the shape of the accommodating panel <NUM> may be deformed due to the weight of the battery module <NUM>. Accordingly, as the accommodating panel <NUM> is deformed and torn or the accommodating panel <NUM> is melted down, the battery module <NUM> may be separated from the accommodating panel <NUM>.

Considering that the accommodating panel <NUM> is made of an aluminum material for structural rigidity and heat generation, the deformation temperature may be <NUM>.

In some implementations, the temperature of the module case <NUM> including a cell assembly <NUM> where thermal runaway has occurred may also be similar to that of the accommodating panel <NUM>. That is, when the temperature of the base panel <NUM>, which is a lower surface of the module case <NUM>, reaches a preset allowable temperature or higher, the tensile strength of the base panel <NUM> may be lower than the tensile strength of the base panel <NUM> at room temperature.

Ultimately, as the base panel <NUM> is deformed or melted, the cell assembly <NUM> may be separated from the battery module <NUM> and the accommodating panel <NUM>.

That is, referring to <FIG>, the entire battery module <NUM> may be separated from the accommodating panel <NUM>. In addition, referring to <FIG>, the cell assembly <NUM> of the battery module <NUM> may be separated from the module case <NUM> and the accommodating panel <NUM> in the direction of gravity (the g-direction).

Considering that the main material of the base panel <NUM> is an aluminum material, the allowable temperature may be <NUM>.

<FIG> shows a typical example of an accommodating panel. <FIG> shows another example of an accommodating panel <NUM> based on some embodiments of the disclosed technology. <FIG> and <FIG> show an example in which the thermal resistance portion 3092a extends in the form of a hole along one side of the battery module <NUM>. However, this is only an example, and the thermal resistance portion 3092a may be provided in the shape of a groove or made of a material with a different thermal conductivity.

In addition, referring to <FIG> and <FIG>, the thermal resistance portion 3092a may be provided in the form of a single hole in parallel with one side of the battery module <NUM>, but the thermal resistance portion 3092a may be continuously or discontinuously provided in the form of a plurality of holes on one side of the battery module <NUM>.

Referring to <FIG>, a typical battery pack may include an accommodating panel <NUM> accommodating the one or more battery modules <NUM>. The accommodating panel <NUM> may form a lower surface of the battery pack <NUM>.

In <FIG> and <FIG>, for the sake of convenience, an accommodating panel <NUM> is expressed in a rectangular shape, and among edges of the accommodating panel <NUM>, a long edge is illustrated to extend in the Y-direction, and a short edge is illustrated to extend in the X-direction. In addition, the battery module <NUM> is illustrated with an example in which eight battery modules are disposed in four rows of two on the accommodating panel <NUM>, but this is only one example, and the disposition method and the number of accommodated battery modules may vary.

Referring to <FIG>, the accommodating panel <NUM> has a first bottom surface <NUM> supporting the battery module <NUM> and a second bottom surface <NUM> connecting the first bottom surfaces therebetween. The second bottom surface <NUM> may include a thermal resistance portion 3092a having a different thermal conductivity or a different thermal resistance value from that of the first bottom surface <NUM>.

Referring to <FIG>, an example is illustrated in which the comparting portion <NUM> is omitted and thus the thermal resistance portion 3092a is exposed to the outside.

The first bottom surface <NUM> may support a lower surface of the battery module <NUM>, that is, the base panel <NUM>. When a plurality of base panels <NUM> are provided, the base panels <NUM> or the battery modules <NUM> may be disposed separately from each other by the comparting portion <NUM>.

In some implementations, depending on whether a battery module <NUM> includes a first flange portion <NUM> and a second flange portion <NUM> extending from both sides of a module case <NUM> in a direction away from the module case <NUM>, the comparting portion <NUM> may not completely separate the battery module <NUM>, but rather it may separate only a part of the module case <NUM> except for the first flange portion <NUM> and the second flange portion <NUM>, for example, only a base panel or a connecting panel.

For the sake of convenience, <FIG> omits the first flange portion <NUM>, the second flange portion <NUM>, and the comparting portion <NUM> supporting the two flange portions <NUM>, <NUM>.

Referring to <FIG>, the thermal resistance portion 3092a may be positioned between the plurality of battery modules <NUM>. The accommodating panel <NUM> may further include: a plurality of first bottom surfaces <NUM> supporting the plurality of battery modules <NUM>; and a second bottom surface <NUM> disposed between the plurality of first bottom surfaces <NUM> to connect the plurality of first bottom surfaces <NUM>.

In addition, the second bottom surface <NUM> may include a thermal resistance portion 3092a provided in the form of a hole (or groove, or a material having different thermal conductivity).

When any one battery module BM1 and the other battery module BM2 among the plurality of battery modules <NUM> are explained as an example, the thermal resistance portion 3092a may be positioned between the two battery modules BM1, BM2. In addition, the thermal resistance portion 3092a may also be disposed between other battery modules that are adjacent to the two battery modules BM1, BM2 in the X-direction.

When the accommodating panel <NUM> is viewed from above, a heat resistance portion 3092a disposed in an area positioned near to a right edge of two edges of the accommodating panel <NUM> may be referred to as a right heat-resistant side RHS.

Likewise, when the accommodating panel <NUM> is viewed from above, a heat resistance portion 3092a disposed in an area positioned near to a left edge of two edges of the accommodating panel <NUM> may be referred to as a left heat-resistant side LHS.

Referring to <FIG>, when the plurality of battery modules <NUM> are disposed in two rows, the accommodating panel <NUM> may include a heat resistance portion 3092a between a battery module <NUM> of any one row and a battery module <NUM> of the other row. The heat resistance portion 3092a may be referred to as a middle heat-resistant side MHS.

The thermal resistance portion 3092a may be positioned only between the battery modules <NUM> and does not need to be provided between side surfaces of the accommodating panel, because the temperature of a corresponding first bottom surface <NUM> only needs to be increased by using the thermal resistance portion 3092a for deformation or melting, rather than the thermal resistance value or thermal conductivity of only a part changes to prevent heat from completely escaping.

For example, in an area where the other one battery module BM2 is positioned, the accommodating panel <NUM> may include the thermal resistance portion 3092a only on two of the four side surfaces of the battery module. However, when thermal runaway occurs in the other one battery module BM2, the amount of heat per unit time escaping through the first bottom surface <NUM> is reduced by the thermal resistance portion 3092a, and thus the temperature of the first bottom surface <NUM> may rapidly increase to the deformation temperature or higher.

Referring to <FIG>, among the thermal resistance portions 3092a, the spacing C1 between thermal resistance portions 3092a provided in parallel with the-X direction may be a length along the-Y direction of the battery module <NUM> or longer. Therefore, the area of the first bottom surface <NUM> may be equal to or larger than the area of the base panel <NUM>. Through this, the first bottom surface <NUM> may stably support the battery module <NUM>.

In some implementations, the spacing C1 between the thermal resistance portions 3092a along the Y-direction may be equal to less than an extension length C2 of the thermal resistance portions 3092a along the X-direction (see <FIG>). However, it may vary depending on the shape of the battery module <NUM>.

<FIG> shows another example of the accommodating panel <NUM>. The accommodating panel <NUM> may include a thermal resistance portion 3092a that is disposed so that three of the four side surfaces of the battery module <NUM> may be surrounded by the thermal resistance portion 3092a.

In some implementations, unlike the accommodating panel <NUM> of <FIG>, the accommodating panel <NUM> of <FIG> may also include the thermal resistance portion 3092a between the first accommodating edge 309a and the second accommodating edge 309b, provided in parallel with the X-direction among edges of the accommodating panel <NUM>, and the battery module <NUM>, allowing the temperature of the first bottom surface <NUM> supporting a battery module <NUM> where thermal runaway has occurred to reach the deformation temperature more quickly.

When the first accommodating edge 309a is defined as the rear of the battery pack <NUM> and the second accommodating edge 309b is defined as the front of the battery pack <NUM>, the battery pack <NUM> may further include a rear left heat-resistant side RLHS and a rear right heat-resistant side RRHS and a front left heat-resistant side FLHS and a front right heat-resistant side FRHS between a first accommodating edge 309a positioned in the rear among edges of the accommodating panel <NUM> and the battery module <NUM> and between a second accommodating edge 309b positioned in the front among edges of the accommodating panel <NUM> and the battery module <NUM>, respectively.

When viewed from the front or from the top of the accommodating panel <NUM>, the rear heat resistance portions RLHS, RRHS may be divided into a rear left heat-resistance portion RLHS and a rear right heat-resistance portion RRHS according to the left and right sides.

Likewise, when viewed from the front or from the top of the accommodating panel <NUM>, the front heat-resistance portions FLHS, FRHS may be divided into a front left heat-resistance portion FLHS and a front right heat-resistance portion FRHS according to the left and right sides.

<FIG> shows still another example of the accommodating panel <NUM>. When the accommodating panel <NUM> has a rectangular shape, the accommodating panel <NUM> will include four edges: a first accommodating edge 309a, a second accommodating edge 309b, a third accommodating edge 309c, and a fourth accommodating edge 309d. The second bottom surface <NUM> may also be formed between the four edges 309a, 309b, 309c, 309d and the first bottom surface <NUM>.

In addition, the accommodating panel <NUM> may further include a heat resistance portion 3092a between the four edges 309a, 309b, 309c, 309d and the first bottom surface <NUM>. That is, the accommodating panel <NUM> may include a thermal resistance portion 3092a that is disposed so that all four side surfaces of the battery module <NUM> are surrounded by the thermal resistance portion 3092a.

In other words, when two or more battery modules <NUM> are provided, the thermal resistance portion 3092a may also be positioned between each of the base panels <NUM> and edges of the accommodating panel <NUM>, allowing the temperature of the first bottom surface <NUM> supporting the battery module <NUM> where thermal runaway has occurred to reach the deformation temperature more quickly.

For example, referring to <FIG>, the accommodating panel <NUM> may include a third accommodating edge 309c and a fourth accommodating edge 309c arranged in parallel along the Y-direction among the four edges 309a, 309b, 309c, 309d.

When the third accommodating edge 309c is at the left of the battery pack <NUM> and the fourth accommodating edge 309d is at the right of the battery pack <NUM>, the battery pack <NUM> may further include a left laterally heat-resistant side LLHS and a right laterally heat-resistant side RLHS between a third accommodating edge 309c positioned at the left of the battery pack <NUM> among edges of the accommodating panel <NUM> and the battery module <NUM> and between a fourth accommodating edge 309d positioned at the right of the battery pack <NUM> among edges of the accommodating panel <NUM> and the battery module <NUM>, respectively.

Claim 1:
A battery pack (<NUM>) comprising:
one or more battery modules (<NUM>), each battery module (<NUM>) including one or more battery cells (<NUM>), and a module case (<NUM>) structured to accommodate the one or more battery cells (<NUM>) and to include a base panel (<NUM>) structured to form a lower surface of the module case (<NUM>) that supports the one or more battery cells (<NUM>);
an accommodating panel (<NUM>) structured to form a bottom surface of a module accommodating space for accommodating the one or more battery modules (<NUM>); and
a comparting portion (<NUM>) coupled to the accommodating panel (<NUM>) to separate each of the one or more battery modules (<NUM>),
wherein the accommodating panel (<NUM>) includes:
a first bottom surface (<NUM>) positioned to face each of the base panels (<NUM>) of the one or more battery modules (<NUM>); and
a second bottom surface (<NUM>) including a heat resistance portion (3092a) connected to at least a part of the first bottom surface (<NUM>) and configured to reduce conduction of heat generated by any one of the battery modules (<NUM>) to another adjacent battery module (<NUM>) through the first bottom surface (<NUM>), characterized in that
the comparting portion (<NUM>) is an angulated U-shaped frame open toward the second bottom surface (<NUM>).