WO2022139148A1

WO2022139148A1 - Battery pack

Info

Publication number: WO2022139148A1
Application number: PCT/KR2021/015013
Authority: WO
Inventors: 이철상
Original assignee: 제이제이모터스 주식회사; 테라팩토리 주식회사
Priority date: 2020-12-21
Filing date: 2021-10-25
Publication date: 2022-06-30
Also published as: KR102308160B1

Abstract

The present invention provides a battery pack comprising: a battery housing having a cooling medium charged therein; at least one battery cell provided inside the battery housing; and a heat absorption member provided on the upper inner surface of the battery housing and having a phase change material therein such that, if the internal temperature of the battery housing is a predetermined temperature or higher, the phase change material phase-changes, exchanges heat with the cooling medium, and absorbs the heat inside the battery housing. The cooling medium comprises a phase change material in an oil and powder form, transfers heat generated from the battery cell by naturally convecting inside the battery housing by means of heat exchange between the heat absorption member and battery cell, and absorbs the internal heat by means of oil and phase change material.

Description

battery pack

The present invention relates to a battery pack, and more particularly, to a battery pack capable of uniformly controlling the temperature inside the battery pack and preventing fire and explosion due to overheating of the battery pack.

In general, secondary batteries that are easy to apply according to product groups and have electrical characteristics such as high energy density are not only portable devices, but also electric vehicles (EVs) or hybrid vehicles (HVs) driven by an electric drive source, etc. It is universally applied.

A battery pack applied to an electric vehicle, etc. is typically composed of a structure including a plurality of battery cells in a battery housing, and the battery cells include a positive electrode current collector, a separator, an active material, an electrolyte, an aluminum thin film layer, etc. It has a structure capable of charging and discharging by reaction.

When such a battery pack generates power, heat according to an electrochemical reaction is generated, and when this heat remains in the battery cells inside the battery pack, the temperature of the battery cells is increased to deteriorate the operating conditions of the battery cells. Accordingly, not only the power generation efficiency is deteriorated, but also a chain reaction may occur due to the generated heat, which may cause a thermal runaway, which may result in fire and explosion.

Conventionally, in order to suppress the temperature rise of the battery cells due to the use of the battery pack, an air cooling method in which an air fan is provided in the battery pack to spray air or a fluid cooling method in which a refrigerant is filled in the battery pack is adopted, but the battery cell If it is overheated for a long time, there is a disadvantage in that the cooling effect decreases.

In addition, the fire generated in the battery pack mainly occurs due to damage to the battery cell due to the increase in internal temperature.

Therefore, there is a need for a method capable of effectively cooling the battery cell and preventing the spread of fire and explosion.

In the present invention, the battery pack, specifically, the battery pack capable of increasing the battery efficiency by uniformly controlling the temperature inside the battery pack, and preventing fire and explosion due to overheating, overcharging, short circuit and impact of the battery pack would like to provide

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be able

In order to solve the above problems, the present invention provides a battery housing filled with a cooling medium therein, at least one battery cell provided inside the battery housing, and an upper inner surface of the battery housing, and a phase change therein and a heat absorbing member for absorbing internal heat of the battery housing by exchanging heat with a cooling medium while the phase change material undergoes a phase change when the internal temperature of the battery housing including the material rises above a predetermined temperature, wherein the cooling medium includes oil and powder A battery that contains a phase change material in the form of a heat absorbing member and heat exchange with a battery cell, naturally convections inside the battery housing, transfers heat generated from the battery cell, and absorbs internal heat through oil and phase change material pack is provided.

In addition, there is provided a battery pack further comprising a support net formed in a net shape to support and support the lower portion of the heat absorbing member in the battery housing, and to allow the cooling medium to pass therethrough.

In addition, the oil of the cooling medium is formed of oil having flame retardancy and insulation, and when the battery cell is damaged, it flows into the damaged area and removes the gas and electrolyte discharged from the damaged area.

In addition, the circulation line connected to the outside of the battery housing in the form of a loop, the pump member provided on the circulation line and circulating the cooling medium in the battery housing through the circulation line at a constant flow rate, and the temperature of the cooling medium circulated through the circulation line It includes a heat exchanger for controlling the, and the pump member provides a battery pack for adjusting the flow rate of the cooling medium to 0.5 to 1 m / sec to suppress static electricity.

In addition, there is provided a battery pack further comprising an expansion tank that is connected to communicate with the battery housing and accommodates the cooling medium therein to supplement the insufficient cooling medium in the battery housing or to recover the thermally expanded cooling medium in the battery housing.

In addition, the phase change material provides a battery pack including at least one of paraffin wax and natural wax.

In addition, the heat absorbing member provides a battery pack further comprising graphite powder for promoting heat transfer to the phase change material.

In addition, there is provided a battery pack in which a heating paint is applied to an outer surface of the battery housing to increase heat transfer efficiency.

The battery pack according to the embodiment of the present invention can increase battery efficiency by uniformly controlling the temperature inside the battery pack, and the battery cells are damaged or damaged due to abnormal conditions such as overheating, overcharging, short circuit and shock of the battery pack. Even if it is damaged, it is possible to completely block the leakage of gas and electrolyte, effectively preventing the spread of fire and explosion.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be.

1 shows the configuration of a battery pack according to a first embodiment of the present invention.

2 illustrates a configuration in which a plurality of heat-conducting members are provided in a battery pack according to a second embodiment of the present invention.

3 shows the configuration of a battery pack according to a second embodiment of the present invention.

4 shows a configuration in which an expansion tank is provided in the battery pack according to the second embodiment of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

DETAILED DESCRIPTION The detailed description set forth below in conjunction with the appended drawings is intended to describe exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced.

In order to clearly explain the present invention in the drawings, parts not related to the description may be omitted, and the same reference numerals may be used for the same or similar components throughout the specification.

In an embodiment of the present invention, expressions such as “or” and “at least one” may indicate one of the words listed together, or a combination of two or more.

1 shows the configuration of a battery pack 100 according to a first embodiment of the present invention.

Referring to FIG. 1 , the battery pack 100 according to the first embodiment of the present invention may include a battery housing 110 , a battery cell 120 , and a heat absorption member 130 .

The battery housing 110 is a case type with a hollow inside, and is formed in a packaging structure that can surround and protect the battery cell 120 , and an accommodating space for accommodating the battery cell 120 and the cooling medium is formed therein. can

In addition, a safety valve 140 may be provided on one upper side of the battery housing 110 , and the safety valve 140 prevents gas leaking from the battery cell 120 when damage occurs due to overheating of the battery cell 120 . It may be discharged to the outside of the battery housing 110 .

As an example, the safety valve 140 may operate to automatically open when the internal pressure of the battery housing 110 is 1.5 bar or more to prevent explosion of the battery housing 110 .

At least one or more battery cells 120 may be provided in the accommodating space inside the battery housing 110 .

In this case, when a plurality of battery cells 120 are provided, they may be connected in series or parallel to each other and disposed in the receiving space of the battery housing 110 .

In addition, the cooling medium may be filled in the receiving space of the battery housing 110 so as to cover the anode and the cathode, which are portions having the highest temperature in the battery cell 120 .

Such a cooling medium naturally convections within the receiving space of the battery housing 110 , and may serve to conduct heat generated in the battery cell 120 and cool it at the same time.

In this embodiment, the cooling medium may be formed by mixing a phase change material and an antioxidant in oil, and one or two or more types of the phase change material may be used.

As an example, the cooling medium may be prepared by mixing a small amount of antioxidant and two phase change materials in powder form with different melting points in oil.

Here, as the oil, a product with a flash point of 300° C. or higher may be used to ensure fire stability, and for example, mineral oil-based oil having flame retardant performance and insulation secured, ester-based synthetic oil, or silicone oil may be used. .

In addition, as the phase change material, paraffin wax, natural wax, etc. may be used, and when heat of about 40° C. or higher is generated in the battery cell 120 , it may melt and absorb heat.

In addition, as the antioxidant, butylated hydroxytoluene (BHT) or the like may be used.

When the cooling medium having the above configuration is put into the battery housing 110 , in order to prevent shock of the battery cells 120 in the battery housing 110 , a phase change material is first put in, and then oil is put in at room temperature. can do.

At this time, the phase change material may be mainly injected at a location where heat is severe in the battery housing 110 , and when there are two or more phase change materials, they may be injected in a mixed state.

Such a cooling medium conducts heat generated in the battery cell 120 while naturally convection in the battery housing 110 by the oil, and can absorb the heat generated in the battery cell 120 through the heat capacity of the oil. .

In addition, when the internal temperature of the battery housing 110 rises by 40° C. or more due to the heat of the battery cell 120 , the phase change material is melted and heat generated in the battery cell 120 may be temporarily absorbed.

The heat absorbing member 130 may be provided in close contact with the inner surface of the battery housing 110 and may absorb internal heat of the battery housing 110 by exchanging heat with a convection cooling medium in the battery housing 110 .

Specifically, the heat absorbing member 130 may be formed in the form of a pack or pouch made of a metal material such as aluminum, and includes a phase change material therein, so that heat is generated from the battery cell 120 . When generated, the phase change material may absorb internal heat of the battery housing 110 while melting from a solid form to a liquid form.

In addition, the heat absorbing member 130 may further include graphite powder as a heat transfer promoter together with the phase change material.

In the case of paraffin wax and natural wax used as phase change materials in this embodiment, a large amount of energy equivalent to 40 times the volume can be removed at once by heat of fusion during phase change, but by having low thermal conductivity, this To solve the problem, graphite powder, which is a heat transfer accelerator, can be mixed and used.

Accordingly, in the present embodiment, a phenomenon in which the heat transfer ability is reduced can be remarkably improved without reducing the heat absorption power due to the melting phenomenon of the phase change material by including a predetermined amount of graphite powder in the phase change material.

The heat absorbing member 130 configured as described above may be installed in a position where heat is generated in the battery housing 110 . As an example, the battery housing 110 adjacent to a bus bar of the battery cell 120 . It may be installed on the upper inner surface of the inner body, and in some cases may be additionally installed on the side surface of the battery housing 110 .

Furthermore, the heat absorbing member 130 is installed in close contact with the inner surface of the upper and side edges of the battery housing 110 , so that the absorbed heat can be easily discharged to the outside of the battery housing 110 .

In addition, a support net 150 made of a metal material for supporting the heat absorbing member 130 may be installed in the upper portion of the battery housing 110 .

At this time, the support net 150 supports and supports the lower portion of the heat absorption member 130 so that the upper surface of the heat absorption member 130 is in close contact with the upper inner surface of the battery housing 110 , and a cooling medium is formed through a hole between the nets. can flow.

Meanwhile, the battery pack 100 of the present embodiment may be provided with a heat-conducting member 160 interposed between each of the plurality of battery cells 120 .

2 illustrates a configuration in which a plurality of heat-conducting members 160 are provided in the battery pack 100 according to the second embodiment of the present invention.

Referring to FIG. 2 , the heat-conducting member 160 may be formed of a material having high thermal conductivity, such as a metal material, and may be formed in a plate shape to be provided in close contact between the plurality of battery cells 120 .

Specifically, the heat-conducting member 160 provided in close contact with each other between the plurality of battery cells 120 has an upper end extending upward to support the support net 150 to prevent the support net 150 from sagging, and the battery It may serve to transfer the heat generated in the cell 120 toward the cooling medium and the heat absorbing member 130 .

In addition, a heating paint may be applied to the outer surface of the battery housing 110 to increase heat transfer efficiency.

As described above, the battery pack 100 according to the first embodiment of the present invention can uniformly control the temperature inside the battery housing 110 through the cooling medium filled in the battery housing 110 .

In particular, when heat is generated in the battery cell 120 and the internal temperature of the battery housing 110 increases, the cooling medium conducts and cools the heat generated in the battery cell 120 through natural convection, and the heat absorbing member Through 130 , a rapid temperature rise in the battery housing 110 may be suppressed.

In addition, the fire generated in the battery pack 100 mainly occurs due to the damage of the battery cell 120 due to the increase in internal temperature. can lead

Accordingly, the battery pack 100 of the present embodiment can uniformly control the internal temperature of the battery housing 110 , thereby preventing thermal runaway of the battery cell 120 and its damage, and Even if the cell 120 is damaged, the cooling medium flows into the damaged area where the gas and the electrolyte are ejected, and at the same time, the cooling medium is forcibly circulated to remove the gas and the electrolyte, thereby preventing the gas and the electrolyte from contacting external oxygen. It can prevent fire and explosion from occurring.

Meanwhile, FIG. 3 shows the configuration of the battery pack 200 according to the second embodiment of the present invention.

Referring to FIG. 3 , the battery pack 200 according to the second embodiment of the present invention is a cyclic configuration of the battery pack 100 of the first embodiment described above, and includes a battery housing 110 and a battery cell 120 . ) and the heat absorbing member 130 , and may include a circulation line 210 , a heat exchanger 220 , and a pump member 230 .

That is, the battery pack 200 according to the present embodiment may be configured as an oil circulation type to improve cooling performance, and accordingly, insulating oil may be filled in the accommodating space in the battery housing 110 .

Also in this embodiment, the heat absorbing member 130 may be provided on the inner surface of the battery housing 110 , and the heat absorbing member 130 exchanges heat with oil convecting in the battery housing 110 to heat the battery housing. (110) can absorb the internal heat.

Furthermore, the heat absorbing member 130 is installed on the inner side of the upper and side edges of the battery housing 110 , so that the absorbed heat can be easily discharged to the outside of the battery housing 110 .

The circulation line 210 is a pipe through which oil flows, and may be connected to the outside of the battery housing 110 in the form of a loop so that the oil in the battery housing 110 can be discharged and recovered to the outside and circulated.

The heat exchanger 220 may be provided on the circulation line 210 to control the temperature of the oil circulated through the circulation line 210 .

That is, the heat exchanger 220 may heat exchange with the oil circulated through the circulation line 210 to adjust the temperature of the oil to an appropriate temperature.

The pump member 230 is provided on the circulation line 210 to circulate the oil in the battery housing 110 through the circulation line 210 at a constant flow rate.

As an example, the oil circulated through the circulation line 210 and introduced into the battery housing 110 may generate static electricity when the flow rate exceeds 1 m/sec. The flow rate can be adjusted to 0.5 to 1 m/sec.

In addition, if the flow path of the circulation line 210 is too narrow, there is a possibility of generating static electricity along with turbulence. For example, when the pump member 230 pumps at 1 liter per minute, the flow path should have a diameter of 4.5 mm or more. do.

In addition, a flow rate sensor (not shown) for detecting the flow rate of oil may be provided on the circulation line 210 , and the pump member 230 is pumped according to the flow rate value of the oil detected by the flow rate sensor (not shown). By controlling the flow rate of the oil circulated through the circulation line 210 can be adjusted to be an appropriate flow rate.

Meanwhile, the battery pack 200 of this embodiment may further include an expansion tank 240 .

4 shows a configuration in which the expansion tank 240 is provided in the battery pack 200 according to the second embodiment of the present invention.

Referring to FIG. 4 , an expansion tank 240 may be connected to an upper portion of the battery housing 110 through a connection pipe 250 .

Here, the connection pipe 250 is provided to be connected between the battery housing 110 and the expansion tank 240 , and a discharge flow path communicating the battery housing 110 and the expansion tank 240 in the connection pipe 250 ( 251) may be formed.

The expansion tank 240 is a container with a hollow inside, and may be provided to replenish oil and eliminate thermal expansion of oil, and a pinhole 241 is formed in the cover of the expansion tank 240, so that the battery housing ( 110) The gas generated inside may be naturally discharged through the pinhole 241.

In addition, the connecting pipe 250 connected between the battery housing 110 and the expansion tank 240 may have a diameter of 1/10 or less of a length.

Accordingly, when the discharge flow path 251 inside the connection pipe 250 is narrowly formed, and the oil is discharged to the expansion tank 240 through the discharge flow path 251 due to thermal expansion, convection is generated inside the discharge flow path 251 can be prevented from occurring.

At this time, when the high-temperature oil flowing into the discharge passage 251 causes convection inside the discharge passage 251, the high-temperature oil may be oxidized. /10 or less.

As described above, the battery pack 200 according to the second embodiment of the present invention is configured to forcibly circulate the oil filled in the battery housing 110 to the outside to dissipate internal heat to the outside, thereby increasing cooling efficiency. and, through this, the temperature inside the battery housing 110 can be uniformly controlled to increase battery efficiency.

In addition, it is possible to uniformly control the internal temperature of the battery housing 110 to prevent thermal runaway of the battery cell 120 and its damage, and even if the battery cell 120 is damaged, oil is converted into gas and electrolyte. By removing the gas and the electrolyte while flowing into the ejected damaged part and the oil is forcibly circulated, it is possible to prevent the gas and the electrolyte from coming into contact with external oxygen, thereby preventing fire and explosion.

As described above, the battery packs 100 and 200 according to the embodiment of the present invention can increase battery efficiency by uniformly controlling the temperature inside the battery pack, and overheat, overcharge, short circuit and Even if the battery cell 120 is damaged or damaged due to an abnormal state such as an impact, it is possible to completely block the leakage of gas and electrolyte, thereby effectively preventing the spread of fire and explosion.

The embodiments of the present invention disclosed in the present specification and drawings are merely provided for specific examples in order to easily explain the technical contents of the present invention and help the understanding of the present invention, and are not intended to limit the scope of the present invention.

Therefore, the scope of the present invention should be construed as including all changes or modifications derived based on the technical spirit of the present invention in addition to the embodiments disclosed herein are included in the scope of the present invention.

The battery pack according to the embodiment of the present invention can increase battery efficiency by uniformly controlling the temperature inside the battery pack, and can prevent fire and explosion due to overheating of the battery pack, so that it is easy for electric vehicles, etc. Of course, it can be effectively applied to various industrial fields in which the battery pack is used.

Claims

a battery housing with a cooling medium filled therein;

at least one battery cell provided inside the battery housing; and

It is provided on the upper inner surface of the battery housing, and when the internal temperature of the battery housing is higher than a predetermined temperature by including a phase change material therein, the phase change material exchanges heat with the cooling medium while changing the phase of the battery housing. Including a heat absorbing member for absorbing internal heat,

The cooling medium is

It contains a phase change material in the form of oil and a powder, and naturally convects inside the battery housing by heat exchange with the heat absorbing member and the battery cell to transfer heat generated in the battery cell, and the oil and the phase change A battery pack that absorbs internal heat through the material.
The method of claim 1,

The battery pack further comprising a support net that supports and supports the lower portion of the heat absorbing member in the battery housing and is formed in a net shape to allow the cooling medium to pass therethrough.
The method of claim 1,

The oil of the cooling medium,

The battery pack is formed of oil having flame retardancy and insulation, and when the battery cell is damaged, flows into the damaged area and removes the gas and electrolyte discharged from the damaged area.
The method of claim 1,

a circulation line connected to the outside of the battery housing in a loop shape;

a pump member provided on the circulation line and circulating the cooling medium in the battery housing through the circulation line at a constant flow rate; and

and a heat exchanger for controlling the temperature of the cooling medium circulated through the circulation line,

The pump member is a battery pack for controlling the flow rate of the cooling medium to 0.5 to 1 m / sec to suppress static electricity.
5. The method of claim 4,

and an expansion tank connected to communicate with the battery housing and accommodating a cooling medium therein to supplement the insufficient cooling medium in the battery housing or to recover the thermally expanded cooling medium in the battery housing.
The method of claim 1,

The phase change material is

A battery pack comprising at least one of paraffin wax and natural wax.
The method of claim 1,

The heat absorbing member,

The battery pack further comprising graphite powder for promoting heat transfer to the phase change material.
The method of claim 1,

A battery pack in which heating paint is applied to an outer surface of the battery housing to increase heat transfer efficiency.