CN117378081A - Secondary battery - Google Patents

Abstract

The present disclosure relates to a secondary battery, one example of which includes a case made of metal and at least one battery cell accommodated in the case, wherein the case includes a coolant stored in a hollow portion formed between an inner surface facing the battery cell and an outer surface spaced apart from the inner surface.

Description

Secondary battery

Technical Field

The present invention relates to a secondary battery capable of suppressing a heat propagation phenomenon that causes other secondary batteries in the vicinity to continue to overheat in the event of thermal runaway.

The present application claims the benefit of priority based on korean patent application No. 10-2022-0047720, which was filed on 18 th 4 months of 2022, and korean patent application No. 10-2022-0185543, which was filed on 27 th 12 months of 2022, and all matters disclosed in the documents of these two korean patent applications are included as part of the present specification.

Background

Unlike primary batteries, secondary batteries can be charged, and due to the potential for miniaturization and large capacity of secondary batteries, a great deal of research and development has been conducted on secondary batteries in recent years. As technology development and demand for mobile devices increase, and as electric vehicles and energy storage systems occur in response to the demand for environmental protection, demand for secondary batteries as energy sources increases rapidly.

Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries based on the shape of a battery case. In the secondary battery, an electrode assembly mounted inside a battery case is a chargeable/dischargeable power generation device composed of a laminate structure of electrodes and separators.

Since the secondary battery needs to be continuously used for a long time, it is necessary to effectively control heat generated during the charge and discharge. In addition, if the secondary battery is overcharged or an external short circuit occurs and an overcurrent is applied, the current increases to cause a temperature increase, and the temperature increase causes a current to increase again, thereby causing a feedback chain reaction, ultimately resulting in a catastrophic condition of thermal runaway.

In addition, if secondary batteries are combined together in the form of a battery module or a battery pack, a heat propagation phenomenon occurs in which thermal runaway of one secondary battery causes other secondary batteries in the vicinity to continuously overheat. Further, since there is a high risk of ignition due to the combustible gas discharged from the overheated secondary battery and due to the ignition source (e.g., a heated electrode), it is necessary to suppress such risk of ignition.

[ related art literature ]

(patent document 1) korean patent laid-open No. 10-1270796 (laid-open in 2013, 6, 5 days)

Disclosure of Invention

Technical problem

The present invention is directed to providing a secondary battery capable of effectively suppressing and preventing a heat propagation phenomenon due to thermal runaway generated in the secondary battery.

However, technical problems to be solved by the present invention are not limited to those described above, and other problems not mentioned will be apparent to those of ordinary skill in the art from the following description of the present invention.

Technical proposal

The present invention relates to a secondary battery, which in one example includes: a metal shell; and at least one battery cell accommodated in the case, wherein the case includes a coolant stored in a hollow portion formed between an inner surface facing the battery cell and an outer surface spaced apart from the inner surface.

In an exemplary embodiment of the invention, the hollow portion is provided with open access openings on both sides of the housing.

In addition, both sides of the housing may be coupled with a side adaptor sealing the inlet and outlet of the hollow portion from the outside.

Here, the side adaptor is provided with grooves joined to the inner and outer surfaces of the housing, and the inlet and outlet of the hollow portion communicate with each other within the grooves.

Further, the side adaptor is provided with an injection hole exposing a portion of the inlet and outlet of the hollow portion to inject the agent from the outside, and the injection hole is sealed by the blocking portion.

The blocking portion is made of a material having a relatively low melting point compared to the housing.

In addition, the injection hole may be provided at an upper portion of the housing.

In addition, the secondary battery of the present invention may be provided with: a side cover coupled to the side adapter and forming an inner space in which electrode leads of the battery cell are located; and a bus bar disposed inside the side cover and electrically connected to the electrode lead, a portion of the bus bar exposed through an opening disposed in the side cover forming an electrode terminal.

According to an exemplary embodiment of the present invention, the bus bar is provided with a discharge hole formed on the electrode terminal, wherein when the blocking portion is melted, the coolant and/or water vapor stored in the hollow portion of the case is discharged from the discharge hole via the injection hole.

According to an exemplary embodiment, a filter for filtering out particles exceeding a prescribed size may be installed in the drain hole.

Meanwhile, according to an exemplary embodiment of the present invention, the secondary battery further includes: and a guide body disposed to face the bus bar at an inner portion of the side cover, wherein the guide body guides an air flow generated by the battery cell and the coolant and/or the water vapor discharged through the injection hole to the discharge hole.

The guide body may be provided with a plurality of guide plates dividing the air flow generated in the battery cells and the coolant and/or the water vapor discharged through the injection holes into a plurality of sub-flows.

In addition, the guide body is provided to be closely attached to the inner surface of the side adapter, and may be provided with a through hole corresponding to the injection hole of the side adapter.

In addition, a filter that filters out particles exceeding a prescribed size is installed in the drain hole, and the guide body may be provided with a storage space formed in an inlet region of the filter.

In addition, a storage space may be provided downstream of the injection hole.

Advantageous effects

According to the secondary battery having the above-described configuration of the present invention, the coolant stored inside the case can rapidly absorb and release heat in a high temperature rising environment (e.g., rapid charge during normal use), thereby suppressing occurrence of thermal runaway and maintaining performance and life without high temperature rising.

In addition, when thermal runaway occurs in the secondary battery, the present invention can suppress heat propagation by the heat insulating effect of the coolant stored inside the case, and suppress flames by greatly reducing the risk of ignition by cooling the ignition source (e.g., combustible gas) discharged from the overheated battery cell and the heat-generating electrode when the low-melting-point barrier portion sealing the coolant is melted and discharged as coolant and/or water vapor.

Further, the present invention can effectively suppress the risk of external fire caused by the ignition source of high-temperature particles by installing a filter that filters out particles exceeding a certain size in a discharge hole provided in a secondary battery.

However, technical effects of the present invention are not limited to those described above, and in the following description of the present invention, other effects not mentioned will be apparent to those of ordinary skill in the art.

Drawings

The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the detailed description, serve to provide a further understanding of the technical spirit of the present invention. Accordingly, the invention is not to be construed as limited by the accompanying drawings.

Fig. 1 is a perspective view of a secondary battery according to a first embodiment of the present invention.

Fig. 2 is an exploded perspective view of the secondary battery in fig. 1.

Fig. 3 is a detailed view of a case of the secondary battery.

Fig. 4 is a diagram of a structure in which the side adapter is coupled to a case of the secondary battery.

Fig. 5 and 6 are diagrams showing a state in which a housing incorporating the side adapter is filled with coolant and sealed.

Fig. 7 is a view showing a state in which the side cover and the bus bar are coupled to the side portion of the case.

Fig. 8 is a view showing a state in which the coolant stored in the casing is discharged to the discharge hole together with the high-temperature gas.

Fig. 9 is an exploded perspective view of a secondary battery according to a second embodiment of the present invention.

Fig. 10 is a front view showing a mounting structure of the guide body.

Fig. 11 is a cross-sectional view of the discharge hole and the guide body.

Fig. 12 is a view showing a state in which the coolant stored in the casing is guided to be discharged to the discharge hole together with the high-temperature gas in the second embodiment of the invention.

Detailed Description

While the invention is susceptible to various modifications and alternative embodiments, specific embodiments are described in detail below.

It will be understood, however, that the invention is not limited to the specific embodiments described herein, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In this application, it should be understood that the terms "comprises" or "comprising," for example, are intended to specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, and do not preclude the presence or addition of one or more other features or integers, steps, operations, elements, components, or groups thereof.

In addition, in this application, when a portion such as a layer, a film, a region, a plate, or the like is referred to as being "on" another portion, this includes not only the case where the portion is "directly" on "another portion but also the case where another portion is interposed therebetween. On the other hand, when a portion such as a layer, a film, a region, a plate, or the like is referred to as being "under" another portion, this includes not only a case where the portion is "directly" under "another portion but also a case where another portion is interposed therebetween. In addition, being disposed "on" in this application may include the case of being disposed at the bottom and the top.

The present invention relates to a secondary battery, and in one example, includes: a metal housing; and at least one battery cell accommodated in the case, wherein the case includes a coolant stored in a hollow portion formed between an inner surface facing the battery cell and an outer surface spaced apart from the inner surface. In other words, the present invention includes a configuration in which the housing itself stores the coolant.

According to the secondary battery having the above-described configuration of the present invention, the coolant stored inside the case can rapidly absorb and release heat in a high temperature rising environment (e.g., rapid charge during normal use), thereby suppressing occurrence of thermal runaway and maintaining performance and life without high temperature rising.

In addition, when thermal runaway occurs in the secondary battery, the present invention can suppress heat propagation by the heat insulating effect of the coolant stored inside the case, and suppress flames by greatly reducing the risk of ignition by cooling the ignition source (e.g., combustible gas) discharged from the overheated battery cell and the heat-generating electrode when the low-melting-point barrier portion sealing the coolant is melted and discharged as coolant and/or water vapor.

[ examples of carrying out the invention ]

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, front, rear, upper, lower, left, right, and middle directions indicating relative positions are intended to aid understanding of the present invention, and unless otherwise indicated, directions shown in the drawings are used.

First embodiment

Fig. 1 is a perspective view of a secondary battery 10 according to a first embodiment of the present invention, and fig. 2 is an exploded perspective view of the secondary battery 10 of fig. 1.

As shown in the drawings, the secondary battery 10 of the present invention includes a case 100 made of metal and at least one battery cell 200 accommodated in the case 100. As one example, in the illustrated exemplary embodiment, the battery cell 200 is a pouch type battery cell 200 having a bi-directional terminal, and two pouch type battery cells 200 are accommodated in the case 100.

Fig. 3 is a detailed view of the case 100 of the secondary battery 10, in which the case 100 has a hollow 102 formed between an inner surface facing the battery cell 200 and an outer surface spaced apart from the inner surface, and a coolant is stored in the hollow 102 provided in the thickness of the case 100.

The housing 100 may be integrally formed with the hollow 102 by extrusion molding a metal material such as aluminum, stainless steel, or an alloy thereof. In the illustrated exemplary embodiment, the case 100 is composed of a main case 110 having a cross-sectional shape of the english letter lower case "n" and a bottom plate 120 coupled to an opening at a lower portion, in consideration of easy storage of the battery cell 200, cost of extrusion molding, and the like.

The hollow portion 102 has an open inlet and outlet 104 on both sides of the housing 100. This allows for the direction of continuous extrusion of the main housing 110 and also to ensure that the hollow 102 is well coated with coolant.

Since the hollow portion 102 of the case 100 is open on both sides, a separate sealing structure is required to store the coolant. In order to seal the coolant, in the present invention, the inlet and outlet 104 of the hollow portion 102 is coupled to both sides of the housing 100 with respect to the side adaptor 300 sealed from the outside. Fig. 4 shows the structure of the side adapter 300 coupled to the housing 100.

The side adapter 300 has grooves 310 that engage the inner and outer surfaces of the housing 100. Edges of the case 100 are inserted into the grooves 310 to be engaged with each other, and a solid seal is formed by welding or the like. Further, the inlet and outlet 104 of the hollow 102 provided in the groove 310 of the side adapter 300 communicate with each other in the groove 310. That is, the bottom surfaces of the grooves 310 are spaced apart to form a space with respect to the inlet and outlet 104 of the hollow 102, and thus, the side adaptor 300 can flow the coolant with each other in the grooves 310 while sealing the coolant in the hollow 102 from leaking to the outside.

Further, the side adaptor 300 has a pouring orifice (spot hole) 320 exposing a portion of the inlet and outlet 104 of the hollow portion 102 to be poured from the outside, and the pouring orifice 320 is sealed by a blocking portion 330. Fig. 5 and 6 are diagrams showing a state in which the housing 100 incorporating the side adapter 300 is filled with the coolant W and sealed. Fig. 5 shows a side sectional view, and fig. 6 shows a state in which the injection hole 320 is sealed by the stopper 330.

The injection hole 320 is formed in a structure penetrating the bottom surface of the recess 310. Inside the groove 310, the inlets and outlets 104 of the hollow portions 102 are connected to each other so that even if the coolant W is injected into the partially opened coolant injection holes 320, the coolant W is injected into all the hollow portions 102. When the injection of the coolant W is completed, the injection hole 320 is sealed with the blocking portion 330 to complete the sealing. Here, in view of deflation or the like, it may be advantageous to place the injection hole 320 at the upper portion of the housing 100 to facilitate injection of the coolant W.

In addition, the blocking part 330 is made of a material having a relatively low melting point compared to the case 100. The blocking portion 330 may be made of various materials such as metal, nonmetal, synthetic resin, rubber, etc. It is also possible to manufacture a separate blocking portion 330 and bond the blocking portion 330 to the injection molding hole 320, and close the injection molding hole 320 by a technique such as brazing or soldering.

The secondary battery 10 of the present invention helps to suppress occurrence of thermal runaway and maintain performance and life by allowing the coolant W stored in the case 100 to rapidly absorb and release heat in a high temperature rising environment (e.g., during normal rapid charge).

In addition, in the case of the thermal runaway phenomenon in the secondary battery 10, the present invention can suppress heat propagation to the surroundings by the heat insulation effect of the coolant W stored inside the case 100, and suppress flames by greatly reducing the risk of ignition by cooling the ignition source (e.g., combustible gas) discharged from the overheated battery cell 200 and the heat-generating electrode when the low-melting-point barrier 330 sealing the coolant melts and is discharged as coolant and/or water vapor.

In other words, in the present invention, the coolant stored in the case 100 greatly improves the safety of the secondary battery 10 by performing various functions within the range of heat insulation, heat absorption, heat dissipation, cooling, and fire extinguishing.

In addition, the secondary battery 10 of the present invention may include a side cover 400 coupled to the side adapter 300 and forming an inner space in which the electrode leads 210 of the battery cell 200 are located, and a bus bar 500 disposed inside the side cover 400 and electrically connected to the electrode leads 210 of the battery cell 200. Here, the electrode terminal 510 may be formed by a portion of the bus bar 500 exposed through the cutout 410 provided in the side cover 400. Fig. 7 is a view showing a state in which the side cover and the bus bar are coupled to the side portion of the case.

The position of the cutout 410 may be generally disposed above the center of the secondary battery 10 in height, i.e., the upper portion of the secondary battery 10. This makes it easy to electrically connect to the bus bar 500 exposed through the slit 410, while also serving as a suitable place for discharging the water vapor evaporated by the coolant W stored inside the case 100 from the secondary battery 10.

Further, according to an exemplary embodiment of the present invention, the bus bar 500 may be provided with a discharge hole 520 formed on the electrode terminal 510. Accordingly, when the battery cell 200 is overheated and melts the blocking portion 330 blocking the injection hole 320, the coolant and/or the water vapor stored in the hollow portion 102 of the case 100 passes through the injection hole 320 to cool the high temperature gas generated by the battery cell 200 and the ignition source (e.g., the heated electrode), and then is discharged to the discharge hole 520.

Fig. 8 is a diagram showing a state in which the coolant W stored in the casing 100 is discharged to the discharge hole 520 together with high-temperature gas (exhaust gas). The blocking part 330 blocking the injection hole 320 provided at the upper portion of the case 100 is melted and disappears by the heat of the overheated battery cell 200, so that water vapor is discharged from the injection hole 320 and exhaust gas is discharged from the overheated battery cell 200.

In the case of the pouch-type battery cell 200, the region where the seal is relatively weak is a portion where the electrode lead 210 protrudes, and referring to fig. 2, the electrode lead 210 is located at the lower side of the battery cell 200 with respect to the injection hole 320. Therefore, the water vapor discharged from the upper side of the case 100 and the exhaust gas discharged from the lower side of the battery cell 200 collide in the middle, causing mutual heat exchange, the temperature of the exhaust gas is lowered, and the water vapor and the exhaust gas having the adjusted temperatures are discharged to the outside through the exhaust hole 520. In this way, the internal pressure of the case 100 is released through the proper discharge of the discharge hole 520, and the structural collapse of the secondary battery 10 is prevented.

In addition, according to an exemplary embodiment, the drain hole 520 may be equipped with a filter 530 that filters out particles exceeding a certain size. The filter 530 may effectively suppress the risk that fire sources, which may be hot particles from the overheated battery cell 200, escape to the outside, causing external fires.

Second embodiment

Fig. 9 is an exploded perspective view of a secondary battery 10 according to a second embodiment of the present invention, which further includes a guide body 600 disposed to face a bus bar 500 inside a side cover 400. The guide body 600 serves to guide the air flow generated by the battery cell 200 and the coolant and/or water vapor discharged through the injection hole 320 to the discharge hole 520.

Fig. 10 is a front view showing a mounting structure of the guide body 600, in which a state in which the side cover 400 shown in fig. 10 (a) and the bus bar 500 therein are removed is shown in fig. 10 (b). In the illustrated embodiment, the guide body 600 has a plurality of guide plates 610, whereby the air flow generated by the battery cells 200 and the coolant and/or water vapor discharged through the injection holes 320 are divided into a plurality of sub-streams, as shown in fig. 12. By dividing the gas flow and the coolant into a plurality of sub-flows, the flow is smoother, the cooling is more uniform, and the contact area of the gas and the coolant is increased, thereby improving the overall cooling efficiency.

In addition, fig. 11 is a sectional view of the discharge hole 520 and the guide body 600, wherein the guide body 600 is disposed closely to the inner surface of the side adapter 300 such that the air flow and the coolant directly enter the guide body 600 without being dispersed. Here, the guide body 600 is provided with a through hole 620 corresponding to the injection hole 320 such that the guide body 600 closely disposed on the inner surface of the side adaptor 300 does not block the injection hole 320.

Meanwhile, when the filter 530 filtering out particles exceeding a certain size is installed in the drain hole 520 of the bus bar 500, the guide 600 may be provided with a storage space 630 formed in an inlet region of the filter 530 in response thereto. The storage space 630 is a space where the gas and the coolant stay for a while just before being discharged, so that sufficient cooling can occur again between the gas and the coolant before the gas and the coolant are discharged through the filter 530 and the discharge hole 520, and serves to alleviate clogging at the time of external discharge.

Here, it may be desirable that the storage space 630 is provided downstream of the injection hole 320 so as not to obstruct the flow of coolant and/or water vapor discharged from the injection hole 320.

The invention has been described in more detail above with reference to the drawings and examples. It will be understood, however, that the configuration shown in the drawings or the embodiments described herein is only one embodiment of the present invention, does not represent all technical concepts of the present invention, and various equivalents and modifications that may be substituted for them are possible at the time of filing the present application.

[ description of reference numerals ]

10: secondary battery 100: shell body

102: hollow portion 104: passageway

110: the main body 120: bottom plate

200: cell 210: electrode lead

300: side adapter 310: groove

320: injection hole 330: blocking part

400: side cover 410: incision

500: bus bar 510: electrode terminal

520: discharge hole 530: filter device

600: guide body 610: guide plate

620: through hole 630: storage space

W: cooling agent

Claims (15)

1. A secondary battery, comprising:

a metal shell; and

at least one battery cell accommodated in the case,

wherein the case includes a coolant stored in a hollow portion formed between an inner surface facing the battery cell and an outer surface spaced apart from the inner surface.

2. The secondary battery according to claim 1, wherein the hollow portion is provided with open inlets and outlets on both sides of the case.

3. The secondary battery according to claim 2, wherein both sides of the case incorporate side adapters that seal the inlet and outlet of the hollow portion from the outside.

4. The secondary battery according to claim 3, wherein the side adapter is provided with grooves joined to the inner and outer surfaces of the case, and

the inlet and outlet of the hollow portion communicate with each other within the groove.

5. The secondary battery according to claim 4, wherein the side adapter is provided with a pouring hole exposing a portion of the inlet and outlet of the hollow portion to allow pouring of a pouring agent from outside, and

the injection hole is sealed by a blocking portion.

6. The secondary battery according to claim 5, wherein the blocking portion is made of a material having a relatively low melting point compared to the case.

7. The secondary battery according to claim 6, wherein the filler hole is provided at an upper portion of the case.

8. The secondary battery according to claim 6, wherein the secondary battery is provided with:

a side cover coupled to the side adapter and forming an inner space in which electrode leads of the battery cell are located; and

and a bus bar disposed inside the side cover and electrically connected to the electrode lead, a portion of the bus bar exposed through an opening provided in the side cover forming an electrode terminal.

9. The secondary battery according to claim 8, wherein the bus bar is provided with a discharge hole formed on the electrode terminal,

wherein when the blocking portion is melted, the coolant and/or water vapor stored in the hollow portion of the housing is discharged from the discharge hole via the injection hole.

10. The secondary battery according to claim 9, wherein a filter that filters out particles exceeding a prescribed size is mounted in the discharge hole.

11. The secondary battery according to claim 9, further comprising a guide body provided to face the bus bar at an inner portion of the side cover,

wherein the guide body guides the air flow generated by the battery cell and the coolant and/or water vapor discharged through the injection hole to the discharge hole.

12. The secondary battery according to claim 11, wherein the guide body is provided with a plurality of guide plates dividing the air flow generated in the battery cell and the coolant and/or water vapor discharged through the injection hole into a plurality of sub-streams.

13. The secondary battery according to claim 11, wherein the guide body is provided to be closely attached to an inner surface of the side adapter, and is provided with a through-hole corresponding to the filler hole of the side adapter.

14. The secondary battery according to claim 11, wherein a filter that filters out particles exceeding a prescribed size is mounted in the discharge hole, and

the guide body is provided with a storage space formed in an inlet region of the filter.

15. The secondary battery according to claim 14, wherein the storage space is provided downstream of the filler hole.