KR102633200B1 - battery module - Google Patents

Abstract

A battery module is disclosed. The battery module of the present invention includes a housing whose interior is sealed against the outside; a cooling unit installed on one side of the housing to contact the housing; a plurality of battery cells mounted within the housing; A plurality of porous members each disposed between the plurality of battery cells; and an insulating cooling fluid filled in the housing to submerge the plurality of battery cells and the lower region of the porous member, wherein the plurality of porous members are configured such that the insulating cooling fluid is generated from the plurality of battery cells within the housing. It is characterized in that it can circulate in the vertical direction within the housing while changing phase by heat. According to the present invention, it is possible to provide optimal battery driving efficiency by efficiently cooling battery cells using phase changes such as vaporization and liquefaction of an insulating cooling fluid with electrical insulation properties, and evaporation of the insulating cooling fluid inside the housing. Since liquefaction occurs only by battery cell heat generation and contact with the cooling part without any additional configuration, the overall structure can be implemented compactly by preventing an increase in the volume of the entire battery module.

Description

Battery module {battery module}

The present invention relates to a battery module that can be mounted on electric vehicles, drones, robots, etc.

Generally, due to the need for high output and large capacity, medium-to-large devices such as automobiles use battery modules that electrically connect multiple battery cells and medium-to-large battery packs that include the unit modules.

The battery cells that make up the battery module generate a large amount of heat during the charging and discharging process. In particular, the laminate sheet of pouch-type batteries, which is widely used in high-output, large-capacity battery modules and battery packs, is coated on the surface with a polymer material with low thermal conductivity, making it difficult to effectively cool the temperature of the entire battery cell. If the heat of the battery module generated during the charging and discharging process is not effectively removed, heat accumulation occurs, which ultimately accelerates the deterioration of the battery module and, in some cases, may cause ignition or explosion.

Therefore, a high-output, large-capacity battery module and a battery pack equipped with it necessarily need a cooling device or cooling member to cool the battery cells built into it.

A conventional cooling device includes a passage for coolant (eg, coolant) formed between battery cells or battery modules to effectively remove heat accumulated between stacked battery cells or battery modules.

Such a conventional cooling device has the problem of increasing the overall size of the battery module because it must secure a large number of refrigerant passages to correspond to a large number of battery cells. In addition, as conventional cooling devices stack more battery cells, more components (e.g., tanks, valves, pumps, coolers, etc.) are added, which not only increases the volume of the battery module, but also limits the available space of the system. As the manufacturing process becomes more complex, the manufacturing cost also increases significantly.

In addition, the conventional cooling device must use a structure in which the refrigerant flowing in the cooling passage enters the inlet and exits the outlet, so there is a problem in that the side closer to the inlet side is cooled more and the side closer to the outlet side is cooled less. In other words, the further away from the inlet and the closer to the outlet, the higher the temperature of the coolant and the lower the cooling efficiency. Accordingly, there is a problem that causes a temperature deviation of the secondary battery, and the temperature deviation of the secondary battery leads to a performance deviation of the secondary battery, which leads to a decrease in the performance of the entire battery system.

Republic of Korea Patent Publication No. 10-2554177 (registered on July 6, 2023)

The present invention was developed to solve the above-described conventional problems. Compared to the prior art, the increase in the volume of the battery module is minimized and the overall structure is implemented compactly, thereby reducing the weight increase of the electric vehicle and increasing driving efficiency. The purpose is to provide a battery module that can provide optimal battery driving efficiency by efficiently cooling battery cells using phase changes such as vaporization and liquefaction of an electrically insulating insulating cooling fluid.

According to one aspect of the present invention, a housing whose interior is sealed against the outside; a cooling unit installed on one side of the housing to contact the housing; a plurality of battery cells mounted within the housing; A plurality of porous members each disposed between the plurality of battery cells; and an insulating cooling fluid filled in the housing to submerge the plurality of battery cells and the lower region of the porous member, wherein the plurality of porous members are configured such that the insulating cooling fluid is generated from the plurality of battery cells within the housing. A battery module is provided that can circulate in an upward and downward direction within the housing while changing phase by heat.

The plurality of battery cells may be pouch-type.

The cooling unit may be disposed on the upper side of the housing.

The inside of the housing may have a vacuum state.

The insulating cooling fluid may have a boiling point of 60°C or lower.

The porous member may be made of a material capable of elastically deforming and restoring its shape in response to changes in the distance between a pair of adjacent battery cells.

The porous member may be applied as any one of a non-woven pad, a silicone sponge, and a cellulose pad.

The cooling unit is installed on the upper side of the housing, and the insulating cooling fluid is vaporized by heat generation from the battery cell, rises toward the cooling unit, and then condenses and falls toward the inner bottom surface of the housing between the plurality of porous members. A condensate return passage may be provided.

The plurality of porous members may be arranged to contact the surface of the battery cell.

On both sides of the porous member in contact with the surface of the battery cell, a vapor flow path may be provided so that the insulating cooling fluid is vaporized by heat generation from the battery cell and rises toward the cooling unit.

The steam flow path may be formed in the form of a continuously long groove along the height direction of the porous member.

Each of the plurality of porous members may be in the form of a tube with a through hole formed inside the longitudinal direction.

According to the battery module of the present invention described above, optimal battery driving efficiency can be provided by efficiently cooling the battery cell using phase changes such as vaporization and liquefaction of the insulating cooling fluid with electrical insulation properties, and can provide optimal battery driving efficiency within the housing. Since the vaporization and liquefaction of the insulating cooling fluid occurs only by battery cell heat generation and contact with the cooling part without any additional configuration, the overall structure can be implemented compactly by preventing an increase in the volume of the entire battery module.

In addition, vapor channels are formed on both sides of the porous member in contact with the battery cell to exchange heat with the battery cell and allow the evaporated vapor to quickly move upward, ultimately causing phase changes such as vaporization and liquefaction of the insulating cooling fluid to rapidly repeat. By doing so, battery cooling efficiency can be improved.

In addition, by allowing the porous member to contact the surface of the battery cell with as large an area as possible, the mutual heat exchange area between the battery cell and the insulating cooling fluid absorbed by the porous member can be increased, ultimately improving the cooling efficiency of the battery cell.

1 is a perspective view showing a battery module according to a first embodiment of the present invention;
Figure 2 is a perspective view showing the arrangement structure of the battery cell and the porous member accommodated inside the housing in the battery module according to the first embodiment of the present invention;
Figure 3 is a cross-sectional view taken along line III-III of Figure 1;
Figure 4 is a perspective view showing the porous member of the battery module according to the first embodiment of the present invention;
Figure 5 is a cross-sectional view taken along line V-V of Figure 3;
Figure 6 is a view showing various modifications of the vapor flow path of the porous member in the battery module according to the first embodiment of the present invention;
Figure 7 is a plan cross-sectional view showing a battery module according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. These embodiments only serve to ensure that the disclosure of the present invention is complete and to those skilled in the art to fully convey the scope of the invention. This is provided to inform you. In the drawings, like symbols refer to like elements.

The battery module according to a preferred embodiment of the present invention partially adopts a heat pipe structure, and efficiently cools the battery cells using phase changes such as vaporization and liquefaction of an electrically insulating insulating cooling fluid to achieve optimal battery driving efficiency. can be provided.

Hereinafter, the present invention will be described in detail with reference to various embodiments.

1 to 5, the battery module according to the first embodiment of the present invention includes a housing 100, a cooling unit 200, a plurality of battery cells 300, a plurality of porous members 400, Includes an insulating cooling fluid (500).

The housing 100 forms the exterior, has an accommodating space inside, and has a structure in which the inside is sealed against the outside. A separate valve (not shown) is connected to this housing 100 to inject or discharge the insulating cooling fluid 500, which will be described later, into the housing.

The cooling unit 200 provides low temperature so that the insulating cooling fluid, which will be described later, evaporates and liquefies inside the housing, and is installed on one side of the housing 100 so as to be in contact with the housing.

The housing 100 itself has an internally sealed structure, and similarly, the cooling unit 200 itself has an internally sealed structure.

In an embodiment of the present invention, as shown in FIGS. 1 and 5, the cooling unit 200 is provided with the housing 100 so that the insulating cooling fluid vaporizes inside the housing, moves upward, and then liquefies and falls again downward. It is preferable to install it on the upper side. The cooling unit 200 has an internal space formed to accommodate coolant therein, and a separate valve (not shown) may be connected to inject or discharge coolant from the outside.

Next, as shown in FIGS. 2 and 3, a plurality of battery cells 300 are mounted in the housing 100 to be spaced apart from each other. Specifically, the plurality of battery cells 300 are mounted to be spaced apart from each other along a direction corresponding to the left-right or front-back direction of the housing 100.

In an embodiment of the present invention, the plurality of battery cells 300 can be applied as a pouch-type battery cell, and each individual electrode of the plurality of battery cells 300 is connected to each other by polarity within the housing 100 and then connected to an external device. The electrode 310 is exposed to the outside of the housing 100 for electrical connection.

Next, as shown in FIGS. 2 and 3, the plurality of porous members 400 are respectively disposed between the plurality of battery cells 300, and are arranged to be in contact with the surface of the battery cells 300.

On the other hand, lithium-ion secondary batteries may experience battery swelling, in which the lithium-ion electrolyte inside evaporates and swells, and the porous member 400 elastically deforms and changes shape in response to the expansion of the battery cell. It is desirable to make it from a material that can be restored. In addition, in some cases, the porous member 400 is preferably made of a material that can elastically deform and restore its shape in response to the shape restoration of the battery cell.

In addition, the porous member 400 receives heat above a certain temperature generated from the battery cell while the liquid insulating cooling fluid 500 is injected into the internal porous hole by capillary action, and the liquid insulating cooling fluid vaporizes to the upper side. By allowing it to move upward, cooling of the battery cell can be achieved by absorbing and vaporizing the heat of the battery cell.

Therefore, in order to maximize the cooling efficiency of the battery cell 300, that is, to ensure that the insulating cooling fluid absorbed by the porous member 400 absorbs the heat of the battery cell 300 as much as possible, the porous member 400 is used as a battery It is desirable to maintain close contact with the surface of the cell 300.

In an embodiment of the present invention, the plurality of porous members 400 are formed within the housing 100 as the insulating cooling fluid 500 undergoes a phase change due to heat generated from the plurality of battery cells 300 within the housing 100. It is made so that it can circulate in the up and down directions. More specific details related to this will be described later.

Meanwhile, the gap between the battery cells 300 arranged adjacent to each other can variably increase or decrease due to various factors such as the above-described battery swelling phenomenon, vehicle running vibration, etc. As such, the gap between the battery cells 300 varies. Regardless, it is desirable to stably maintain the porous member 400 in as close contact with the surface of the battery cell 300 as possible.

To this end, in an embodiment of the present invention, the porous member 400 is preferably made of a material that can elastically deform and restore its shape in response to changes in the gap between a pair of adjacent battery cells.

The porous member 400 is made of a porous material so that the insulating cooling fluid 500 is absorbed quickly and over as large an area as possible by capillary action, and is elastically formed to respond to changes in the separation distance between adjacent battery cells as described above. It is made of a material that can contract or expand, and can be applied, for example, as a non-woven pad, a silicone sponge, or a cellulose pad.

Next, as shown in FIG. 5, the insulating cooling fluid 500 is filled in the housing 100 in a predetermined amount so that the plurality of battery cells 300 and the lower region of the porous member 400 are submerged. Specifically, it is preferable that the insulating cooling fluid 500 is sufficiently absorbed into the entire area of the plurality of porous members 400 installed in the housing 100 and filled so that it can contact the surface of the battery cell 300, for example. For example, the injection is performed within 30% of the total space between the plurality of battery cells 300 in the housing 100.

In addition, the insulating cooling fluid 500 is contained within the housing in an amount sufficient to be evenly absorbed through capillary action in the entire area of the porous member 400 in contact with the entire surface (i.e., both sides) of the battery cell 300. It is preferable that the battery cell 300 be injected, so that heat from all areas where the battery cell 300 generates heat can be absorbed as quickly as possible to cool the battery cell.

The insulating cooling fluid 500 is a fluid with no or low electrical conductivity and good heat transfer efficiency, and corresponds to the recommended optimal control temperature of the battery cell so that it can be sufficiently vaporized by the battery heating temperature, for example, to prevent a decrease in battery driving efficiency. It can be applied as a non-electrical conductive material with a boiling point of 60°C or lower. This insulating cooling fluid can be applied as NOVEC 7000 or NOVEC 7100.

In an embodiment of the present invention, the insulating cooling fluid 500 is vaporized by the heat generated by the battery cell 300, rises toward the cooling unit 200, and then condenses and falls toward the inner bottom of the housing 100, as shown in Figures 3 and 3. As shown in FIG. 5, a condensate return passage 410 is provided between the plurality of porous members 400.

In addition, as shown in FIGS. 3 to 5, on both sides of the porous member 400 in contact with the surface of the battery cell 300, the insulating cooling fluid 500 is vaporized by heat generation from the battery cell 300. A steam flow path 420 is provided to easily and quickly rise toward the cooling unit 200.

In an embodiment of the present invention, as shown in FIG. 4, the steam flow path 420 may be formed in the form of a continuously long groove along the height direction of the porous member 400. Here, the height direction means from one end (bottom) of the porous member 400 adjacent to the bottom surface inside the housing 100 to the other end (top) of the porous member 400 adjacent to the cooling unit 200. means the direction of

The porous member 400 itself is made of a porous material, and unless a separate vapor passage 420 is provided, the absorbed insulating cooling fluid is vaporized by battery heat and moves smoothly upward to the upper side where the cooling unit 200 is disposed. There is a problem that makes it difficult for flow to occur.

In other words, vaporization of liquid insulating cooling fluid -> upward movement of vapor -> liquefaction of vapor -> vaporization of liquid insulating cooling fluid occurs repeatedly, making it difficult to quickly change the phase of the insulating cooling fluid for battery cooling. This ultimately results in a decrease in battery cooling efficiency. However, by forming continuous groove-shaped steam passages 420 on both sides of the porous member 400, steam can be allowed to quickly move upward toward the cooling unit 200 along the steam passages 420, which ultimately results in insulation. By inducing a rapid phase change of the cooling fluid, battery cooling efficiency is improved.

In an embodiment of the present invention, a plurality of steam passages 420 may be provided so that a plurality of them are adjacent to each other. For example, one steam passage 420 extends from the bottom of the porous member 400 as shown in FIG. 4. It may be formed in the form of a straight line up to the top, or may be formed in a form in which convex portions on one side and concave portions on the opposite side are alternately repeated along the longitudinal direction of the steam flow path, as shown in FIG. 6(a).

In addition, as shown in FIG. 6(b), the steam flow path 420 may be formed in the form of a grid pattern, and may be applied in any form as long as it can provide a continuous flow path from the bottom to the top of the porous member. do.

Hereinafter, the process of cooling the battery cell through the phase change of the insulating cooling fluid will be described in more detail.

During the initial operation of the battery module according to an embodiment of the present invention, the insulating cooling fluid 500 contained in the housing 100 is absorbed into the porous member 400 by capillary action, and specifically, the porous member 400 ) maintains a state in which most areas in contact with the battery cell 300 are wetted by the insulating cooling fluid.

That is, the porous member 400 is made of a porous material that can implement capillary phenomenon (capillary force) so that the insulating cooling fluid contained in the bottom of the housing 100 can be transferred to the upper part of the housing, and the insulating cooling fluid 500 Can be absorbed into the porous member 400 in a uniform state from the lower part of the porous member corresponding to the bottom inside the housing to the upper part of the porous member corresponding to the upper side of the housing.

Thereafter, when heat is generated from the battery due to battery operation, the insulating cooling fluid 500 absorbed in the porous member 400 receives the heat generated from the battery cell 300 and changes phase into a gaseous state, and at this time, the insulating cooling fluid 500 is absorbed into the porous member 400. The fluid absorbs the heat from the battery cell and cools the battery cell.

In other words, the porous member 400, which is a porous structure, directly receives heat generated from the battery cell while making surface contact with the battery cell 300, and this heat can rapidly vaporize the insulating cooling fluid.

Meanwhile, in order to efficiently absorb the heat generated from the battery cell 300, the boiling point of the insulating cooling fluid is lowered so that the insulating cooling fluid can be easily vaporized even if the heating temperature of the battery cell 300 is not high above a certain level. It is required to be able to easily evaporate (vaporize) and condense (liquefy).

To this end, in an embodiment of the present invention, the inside of the housing 100 is formed into a vacuum. The housing 100 includes a valve (not shown) for injecting/discharging the insulating cooling fluid 500 into the housing, as well as a separate valve (not shown) and a pump for vacuuming the inside of the housing by sucking air inside the housing. (not shown) is connected.

As an example, by partially applying the principle of a heat pipe, the vacuum environment inside the housing 100 is formed with a vacuum pressure of about 10 ^-3 Torr, and accordingly, the boiling point of the insulating cooling fluid is lowered above a certain level to facilitate evaporation and condensation. can do. In the present invention, the battery cell 300, as a heat source that is one of the components for inducing a phase change of the insulating cooling fluid, is located inside the housing 100, unlike a typical heat pipe structure.

In the present invention, in a state in which vacuum pressure is formed inside the housing 100, the insulating cooling fluid 500 is injected into the housing 100 in a set appropriate amount, and the insulating cooling fluid is applied as an insulating fluid with no or low electrical conductivity. . For example, the insulating cooling fluid 500 can be applied with a boiling point of 60°C or lower, such as NOVEC 7000 or NOVEC 7100, and the filling amount is injected within 30% of the amount that can fill the inside of the housing 100. .

In the present invention, the insulating cooling fluid that moves from the lower part of the porous member 400 to the upper part through the capillary phenomenon and is entirely absorbed in the porous member vaporizes through the heat supplied from the battery cell, and as described above, a vacuum atmosphere is created inside the housing. As it is formed, the insulating cooling fluid can vaporize at a lower temperature than at atmospheric pressure. For example, the insulating cooling fluid easily evaporates even at room temperature of 20°C, and as shown in FIG. 5, the evaporated vapor moves toward the upper cooling unit 200 along the vapor passage 420.

By evacuating the inside of the housing 100 to lower the boiling point of the insulating cooling fluid 500, the insulating cooling fluid can vaporize and cool the battery cell even when the heating temperature of the battery cell 300 is, for example, 20°C. there is.

Thereafter, the vapor moving toward the cooling unit 200 is condensed and liquefied by the cooling unit 200, which maintains a low temperature. As shown in FIGS. 3 and 5, the condensate of the insulating cooling fluid is stored in the porous member 400. It is surrounded by battery cells 300 and returns to its initial position by falling to the bottom of the housing 100 corresponding to the direction of gravity along the condensate return passage 410 formed as an empty space between them.

That is, in the present invention, while the battery cell is generating heat, the insulating cooling fluid absorbed in the porous member is vaporized -> moves upward toward the cooling unit through the vapor passage -> vapor is condensed by receiving the low temperature of the cooling unit -> insulating cooling fluid. The condensate moves downward repeatedly along the condensate return passage.

Hereinafter, a battery module according to the second embodiment of the present invention will be described, and repeated descriptions of the same components as those of the first embodiment will be omitted and the same reference numerals will be used for the same components.

The battery module according to the second embodiment of the present invention is different from the first embodiment in the porous pad structure and vapor channel structure, and the remaining configurations are the same.

As shown in FIG. 7, in the second embodiment of the present invention, the plurality of porous members 600 are each formed in the form of a tube with a through hole formed on the inside along the longitudinal direction. Additionally, the plurality of porous members 600 may be formed in the form of circular pipes so that a gap is formed between the plurality of porous members 600 arranged adjacent to each other.

In the drawing, a plurality of tubular configurations are provided to continuously contact each other between the battery cells 300, and this single tubular configuration corresponds to one porous member 600 in the embodiment of the present invention.

Meanwhile, the plurality of porous members 600 may be arranged so that their outer surfaces continuously contact each other, but the present invention is not limited to this and may be arranged to be spaced apart from each other. However, when considering the increase in cooling efficiency of the battery cell 300 due to vaporization of the insulating cooling fluid by further increasing the contact area between the plurality of porous members 600 and the battery cell 300, the plurality of porous members 600 as shown in the drawing It is preferable that 600 are arranged so that they are in continuous contact with each other.

In the second embodiment of the present invention, as shown in FIG. 7, the inner through hole of the porous member 600 functions as a vapor passage 620, and the gap between adjacent porous members 600 returns the condensate. Functions as Euro (610).

In the case of the second embodiment of the present invention, compared to the case of the first embodiment, the contact area between the plurality of porous members 600 and the surface of the battery cell 300 is further increased, so that the overall battery cell cooling efficiency can be further improved. .

That is, the plurality of porous members 600 are in surface contact with the entire surfaces of both sides of the battery cell 300, so that heat transfer efficiency can be further increased by increasing the mutual contact area.

While the present invention has been shown and described in connection with preferred embodiments for illustrating the principles of the invention, the invention is not limited to the construction and operation as shown and described. Rather, those skilled in the art will understand that numerous changes and modifications can be made to the present invention without departing from the spirit and scope of the appended claims.

100: Housing 200: Cooling unit
300: Battery cell 400,600: Porous member
410,610: Condensate return flow path 420,620: Steam flow path
500: Insulating cooling fluid

Claims (12)

a housing sealed internally to the outside;
a cooling unit installed on one side of the housing to contact the housing;
A plurality of battery cells mounted within the housing;
A plurality of porous members each disposed between the plurality of battery cells; and
An insulating cooling fluid filled in the housing to submerge the plurality of battery cells and the lower region of the porous member,
The plurality of porous members are configured to allow the insulating cooling fluid to circulate in an upward and downward direction within the housing while changing phase due to heat generated from the plurality of battery cells within the housing,
The plurality of porous members are arranged to be in contact with the surface of the battery cell, and on both sides of the porous member in contact with the surface of the battery cell, the insulating cooling fluid is vaporized by heat generation from the battery cell, thereby forming the cooling unit. A battery module characterized in that a vapor flow path is provided to rise to the side. According to paragraph 1,
A battery module, wherein the plurality of battery cells are pouch-type. According to paragraph 1,
The battery module, wherein the cooling unit is disposed on an upper side of the housing. According to paragraph 1,
A battery module, characterized in that the interior of the housing is in a vacuum state. According to paragraph 1,
A battery module, characterized in that the insulating cooling fluid has a boiling point of 60°C or lower. According to paragraph 1,
The porous member is a battery module characterized in that it is made of a material that can elastically deform and restore its shape in response to changes in the gap between a pair of adjacent battery cells. According to clause 6,
A battery module, wherein the porous member is applied as one of a non-woven pad, a silicone sponge, and a cellulose pad. According to paragraph 1,
The cooling unit is installed on the upper side of the housing,
A battery characterized in that a condensate return passage is provided between the plurality of porous members so that the insulating cooling fluid is vaporized by heat generation from the battery cell, rises toward the cooling unit, and then condenses and falls toward the inner bottom surface of the housing. module. delete delete According to paragraph 1,
The battery module, wherein the vapor flow path is formed in the form of a groove that is continuously long along the height direction of the porous member.
delete

Images