Secondary battery

Abstract

To provide a secondary battery including a gas pocket for collecting an internal gas and capable of discharging the collected gas.SOLUTION: The present invention relates to a secondary battery. The secondary battery includes an electrode assembly in which electrodes and separation films are alternately laminated, and a cell case which houses the electrode assembly. The cell case includes: a first gas pocket in which a first collection space to collect an internal gas from the cell case is formed and a first discharge part from which the gas located in the first collection space is discharged is provided; and a second gas pocket in which a second collection space to collect the gas discharged from the first discharge part of the first gas pocket is formed and a second discourage part from which the gas located in the second collection space is discharged to the outside is provided.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2020 - 0057375, filed on May 13, 2020, and all the contents disclosed in the document of the Korean patent application are incorporated herein by reference in their entirety.

[0002] The present invention relates to a secondary battery.

Background Art

[0003] Unlike primary batteries, secondary batteries can be recharged and have been frequently researched and developed in recent years due to the possibility of being miniaturized and having a large capacity. With the development of technology and the increasing demand for mobile devices, the demand for secondary batteries as an energy source has been rapidly increasing.

[0004] Secondary batteries can be classified into coin - type batteries, cylindrical batteries, prismatic batteries, and pouch - type batteries according to the shape of the battery case. A secondary battery houses an electrode assembly and an electrolyte. In a secondary battery, the electrode assembly mounted inside the battery case is a power - generating element capable of charge and discharge, which has a laminated structure of electrodes and a separator.

[0005] The electrode assembly can be divided into a jelly - roll type in which a separator is interposed between a sheet - shaped positive electrode and a negative electrode coated with an active material and wound, a stack type in which a large number of positive electrodes and negative electrodes are sequentially laminated with a separator interposed therebetween, and a stack / fold type in which unit cells of the stack type are wound with a long separation film.

[0006] Conventional pouch-type batteries are configured in a form where an electrode assembly is housed inside a pouch. When such a pouch-type battery is charged and discharged, the pouch repeatedly expands and contracts due to gas generation. At this time, if the generated gas remains inside the pouch, it will cause a decrease in battery performance and a change in volume, which is a problem that has an adverse effect on surrounding batteries and structures. Also, when the generated gas exceeds the accommodation limit of the pouch, a vent phenomenon occurs where the gas ruptures and leaks from a structurally weak part. When a vent occurs, there is a problem that the electrolyte leaks and the battery life ends.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] One aspect of the present invention aims to provide a secondary battery provided with a gas pocket portion in which internal gas is collected and the collected gas can be discharged.

Means for Solving the Problems

[0009] The secondary battery according to an embodiment of the present invention includes an electrode assembly in which electrodes and a separator are alternately laminated and a battery case that houses the electrode assembly. The battery case includes a first gas pocket portion in which a first collection space for collecting internal gas of the battery case is formed and a first discharge portion for discharging the gas located in the first collection space, and a second collection space for collecting the gas discharged from the first discharge portion of the first gas pocket portion is formed, and a second gas pocket portion provided with a second discharge portion for discharging the gas located in the second collection space to the outside may be included.

[0010] On the one hand, the battery pack according to an embodiment of the present invention may be a battery pack including a secondary battery according to an embodiment of the present invention.

Advantages of the Invention

[0011] According to the present invention, by providing a gas pocket portion for collecting internal gas in a double layer, a large amount of space for collecting internal gas can be stably secured, and there is a possibility that external air and the internal air of the battery are not directly connected.

[0012] In addition, by forming gas discharge portions that are opened when the pressure exceeds a predetermined value in the gas pocket portions provided in a double layer, the gas accommodated in the gas pocket portions can be easily discharged, so that gas is prevented from bursting and leaking from a structurally weak portion of the battery case, thereby preventing leakage of the electrolyte and extending the life of the battery.

[0013] Furthermore, by positioning a gas sensor inside the gas pocket portion, it is possible to measure the presence or absence of gas generation or the gas components in the collection space.

[0014] Furthermore, by positioning an air pressure sensor inside the gas pocket portion, the air pressure in the collection space can be measured, so that it is easy to monitor the state of the battery.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

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Figure 9

Mode for Carrying Out the Invention

[0016] The object, specific advantages, and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments related to the accompanying drawings. In this specification, when adding reference numerals to the components of each drawing, it should be noted that, as much as possible, the same numbers are assigned to the same components, even if they are shown on other drawings. Further, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. In addition, when explaining the present invention, a detailed description of known technologies that may obscure the gist of the present invention is omitted.

[0017] (Secondary Battery According to an Embodiment)

[0018] FIG. 1 is a cross-sectional view showing a secondary battery according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a main part showing a secondary battery according to an embodiment of the present invention.

[0019] Referring to FIGS. 1 and 2, a secondary battery S1 according to an embodiment of the present invention includes an electrode assembly 200 and a battery case 100 that houses the electrode assembly 200. The battery case 100 includes a first gas pocket portion 120 in which a first collection space 121 is formed and a first discharge portion 122 through which gas is discharged, and a second gas pocket portion 130 in which a second collection space 131 is formed and a second discharge portion 132 through which gas is discharged.

[0020] Further, the secondary battery S1 according to an embodiment of the present invention may further include a gas sensor 150 that measures the presence or absence of gas generation or gas components, and air pressure sensors 160 and 170 that measure air pressure.

[0021] More specifically, the electrode assembly 200 is a power generation element capable of charge and discharge, and the electrodes and the separator may be alternately laminated. At this time, the electrode tab 250 provided at the end of the electrode assembly 200 and the electrode lead 300 may be connected to connect the electrode assembly 200 to an external device.

[0022] The electrode 230 may be composed of a positive electrode 210 and a negative electrode 220. At this time, the electrode assembly 200 may have a structure in which the positive electrode 210 / separator 240 / negative electrode 220 are alternately laminated.

[0023] The electrode lead 300 may include a positive electrode lead connected to the positive electrode tab provided at the end of the positive electrode 210 and a negative electrode lead connected to the negative electrode tab provided at the end of the negative electrode 220.

[0024] The positive electrode 210 may include a positive electrode current collector and a positive electrode active material laminated on the positive electrode current collector.

[0025] The positive electrode current collector may be made of a foil of an aluminum material.

[0026] The positive electrode active material may be made of lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound and mixture containing one or more of these.

[0027] The negative electrode 220 may include a negative electrode current collector and a negative electrode active material laminated on the negative electrode current collector.

[0028] The negative electrode current collector may be made of, for example, a foil made of a copper (Cu) material.

[0029] The negative electrode active material may be a compound or mixture containing a graphite-based material.

[0030] The separator membrane 240 is made of an insulating material and electrically insulates between the positive electrode 210 and the negative electrode 220. Here, the separator membrane 240 may be formed of a polyolefin resin membrane such as polyethylene or polypropylene having microporosity.

[0031] The battery case 100 may accommodate the electrode assembly 200.

[0032] The battery case 100 includes a first gas pocket portion 120 in which a first collection space 121 is formed and a first discharge portion 122 is provided, and a second gas pocket portion 130 in which a second collection space 131 is formed and a second discharge portion 132 is provided.

[0033] Further, the battery case 100 may further include a main body 110 in which a housing portion 111 for housing the electrode assembly 200 is formed.

[0034] The first gas pocket portion 120 may be formed with a first collection space 121 in which the internal gas of the battery case 100 is collected, and may be provided with a first discharge portion 122 through which the gas located in the first collection space 121 is discharged.

[0035] Further, the first gas pocket portion 120 may extend along the side surface of the main body 110 such that the housing portion 111 and the first collection space 121 are connected. Here, the first gas pocket portion 120 may be located on the end side of the main body 110 where the electrode lead 300 is located. At this time, the first gas pocket portions 120 may be respectively located on both end sides of the main body 110.

[0036] The first discharge portion 122 is located on a first through hole 123 that penetrates between the first collection space 121 and the second collection space 131, and can control the opening and closing of the first through hole 123.

[0037] The second gas pocket portion 130 may be formed with a second collection space 131 in which the gas discharged from the first discharge portion 122 of the first gas pocket portion 120 is collected, and may be provided with a second discharge portion 132 through which the gas located in the second collection space 131 is discharged to the outside.

[0038] The second gas pocket portion 130 may be provided above the first gas pocket portion 120 such that the second collection space 131 and the first collection space 121 are connected between the first through holes 123.

[0039] The second discharge portion 132 is located on a second through hole 133 that penetrates between the second collection space 131 and the outside of the battery case 100, and can control the opening and closing of the second through hole 133.

[0040] Here, the first through hole 123 and the second through hole 133 may be provided at positions not facing each other in the direction in which the gas is discharged. At this time, the first through hole 123 and the second through hole 133 may be located at positions not facing each other in the vertical direction.

[0041] FIG. 3 is a plan view showing the first and second discharge portions of the secondary battery according to an embodiment of the present invention, FIG. 4 is a cross-sectional view showing the closed state of the first and second discharge portions of the secondary battery according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view showing the open state of the first and second discharge portions of the secondary battery according to an embodiment of the present invention.

[0042] Referring to FIGS. 3 to 5, the first discharge portion 122 and the second discharge portion 132 are formed with a first incision portion 122c and a second incision portion 132c, are formed of an elastic material, and when the pressure is above a predetermined value, the first incision portion 122c and the second incision portion 132c open, and the first through hole 123 and the second through hole 133 can be opened.

[0043] Here, the elastic material may be formed of at least one of silicon, spandex, fluoroelastomer, ethylene, propylene rubber (EPR), styrene, butadiene rubber (SBR), and butyl rubber (PIB).

[0044] The opening pressures of the first discharge part 122 and the second discharge part 132 may be provided with a difference from each other. At this time, the first discharge part 122 and the second discharge part 132 may be formed of materials having different elasticities, and the opening pressures of the first discharge part 122 and the second discharge part 132 may be provided with a difference from each other. Thereby, it is possible to prevent the first discharge part 122 and the second discharge part 132 from being opened simultaneously and block direct contact between the external air of the battery and the internal air of the battery.

[0045] Here, the opening pressure of the first discharge part 122 may be provided to be greater than the opening pressure of the second discharge part 132. Thereby, gas can be easily discharged from the first discharge part 122 to the second discharge part 132.

[0046] Referring to FIG. 3, the first incision part 122c and the second incision part 132c may be formed by two to four incision lines 122a, 122b, 132a, 132b. Here, the first incision part 122c and the second incision part 132c may be formed by cross-shaped incision lines 122a, 122b, 132a, 132b.

[0047] Referring to FIG. 4, when the first collection space 121 and the second collection space 131 are below a predetermined pressure, the first incision part 122c and the second incision part 132c may close the first through hole 123 and the second through hole 133.

[0048] Referring to FIG. 5, when the first collection space 121 and the second collection space 131 are above a predetermined pressure, the first incision part 122c and the second incision part 132c may open around the incision lines 122a, 122b, 132a, 132b and open the first through hole 123 and the second through hole 133.

[0049] Referring to FIGS. 1 and 2, the gas sensor 150 is provided inside the second gas pocket portion 130 and can measure the presence or absence of gas generation or the gas components in the second collection space 131. At this time, since a specific gas in the second gas pocket portion 130 can be sensed via the gas sensor 150, notification for a specific purpose may be enabled. Here, the gas sensor 150 can sense the generation of carbon dioxide (CO2).

[0050] In addition, the gas sensor 150 may generate at least one or more of a notification signal, a notification sound, or a notification light when gas is generated. Here, for example, when carbon dioxide (CO2) is sensed, the gas sensor 150 may generate at least one or more of a notification signal, a notification sound, or a notification light. Here, the gas sensor 150 includes a notification speaker and a notification LED and may generate a notification sound and a notification light. Also, the gas sensor 150 may be connected to a monitoring device to transmit the generated notification signal.

[0051] The air pressure sensors 160, 170 may be provided inside at least one of the first gas pocket portion 120 or the second gas pocket portion 130 to measure the air pressure. Here, the air pressure sensors 160, 170 are located in the first gas pocket portion 120 and the second gas pocket portion 130 and may measure the air pressure in the first collection space 121 and the second collection space 131.

[0052] At this time, as an example, when the measured air pressure value measured by the air pressure sensors 160, 170 is equal to or higher than a certain pressure, the air pressure sensors 160, 170 may generate at least one or more of a notification sound or a notification light.

[0053] In addition, as another example, the air pressure sensors 160, 170 may transmit the measured air pressure value to a monitoring device. At this time, the monitoring device may be, for example, a battery management system (BMS).

[0054] The secondary battery S1 according to an embodiment of the present invention configured as described above includes a first gas pocket portion 120 and a second gas pocket portion 130 that collect and discharge gas, thereby stably securing a large space in which internal gas is collected and discharging the internal gas so that the external air of the battery and the internal air of the battery are not directly connected.

[0055] Further, by forming a first discharge portion 122 and a second discharge portion 132 that are opened to discharge gas when the pressure in the first gas pocket portion 120 and the second gas pocket portion 130 is equal to or higher than a predetermined pressure, the gas accommodated in the first gas pocket portion 120 and the second gas pocket portion 130 can be easily discharged, thereby extending the life of the battery.

[0056] Furthermore, by positioning a gas sensor 150 inside the second gas pocket portion 130, it is possible to measure the presence or absence of gas generation or the gas component in the second collection space 131.

[0057] (Secondary battery according to another embodiment)

[0058] Hereinafter, a secondary battery according to another embodiment of the present invention will be described.

[0059] FIG. 6 is a cross-sectional view showing a secondary battery according to another embodiment of the present invention, FIG. 7 is a plan view showing the first and second discharge portions of the secondary battery according to another embodiment of the present invention, FIG. 8 is a cross-sectional view showing a closed state of the first and second discharge portions of the secondary battery according to another embodiment of the present invention, and FIG. 9 is a cross-sectional view showing an open state of the first and second discharge portions of the secondary battery according to another embodiment of the present invention.

[0060] Referring to FIGS. 6 to 9, a secondary battery S2 according to another embodiment of the present invention includes an electrode assembly 200 and a battery case 100 that houses the electrode assembly 200. The battery case 100 includes a first gas pocket portion 120 in which a first collection space 121 is formed and a first discharge portion 1122 for discharging gas, and a second gas pocket portion 130 in which a second collection space 131 is formed and a second discharge portion 132 for discharging gas.

[0061] Further, the secondary battery S2 according to another embodiment of the present invention may further include a gas sensor 150 that measures the presence or absence of gas generation or gas components, and air pressure sensors 160 and 170 that measure air pressure.

[0062] The secondary battery S2 according to another embodiment of the present invention is different from the secondary battery according to one embodiment of the present invention described above in that adhesive liquids 1122d and 1132d are further located at the cut lines 1122a, 1122b, 1132a, and 1132b of the first and second discharge portions 1122 and 1132. Therefore, for other embodiments of the present secondary battery S2, the content overlapping with one embodiment of the secondary battery described above is omitted or briefly described, and the description focuses on the differences.

[0063] More specifically, the battery case 100 may accommodate the electrode assembly 200.

[0064] The battery case 100 includes a first gas pocket portion 120 in which a first collection space 121 is formed and a first discharge portion 1122 is provided, and a second gas pocket portion 130 in which a second collection space 131 is formed and a second discharge portion 132 is provided.

[0065] Further, the battery case 100 may further include a main body 110 in which an accommodation portion 111 for accommodating the electrode assembly 200 is formed.

[0066] The first gas pocket portion 120 may be formed with a first collection space 121 in which the internal gas of the battery case 100 is collected, and may be provided with a first discharge portion 1122 through which the gas located in the first collection space 121 is discharged.

[0067] The first gas pocket portion 120 may extend along the side surface of the main body 110 such that the accommodation portion 111 and the first collection space 121 are connected.

[0068] The second gas pocket part 130 may be provided with a second collection space 131 in which the gas discharged from the first discharge part 1122 of the first gas pocket part 120 is collected, and a second discharge part 132 through which the gas located in the second collection space 131 is discharged to the outside.

[0069] The second gas pocket part 130 may be provided above the first gas pocket part 120 such that the second collection space 131 and the first collection space 121 are connected through the first through hole.

[0070] The first discharge part 1122 is located on the first through hole penetrating between the first collection space 121 and the second collection space 131, and can control the opening and closing of the first through hole.

[0071] The second discharge part 132 is located on the second through hole penetrating between the second collection space 131 and the outside of the battery case 100, and can control the opening and closing of the second through hole.

[0072] Since the first discharge part 1122 and the second discharge part 132 are formed with the first incision part 1122c and the second incision part 1132c and are made of an elastic material, the first incision part 1122c and the second incision part 1132c open when the pressure is above a predetermined level, allowing the first through hole and the second through hole to be opened.

[0073] The first incision part 1122c and the second incision part 1132c may be formed by two to four incision lines 1122a, 1122b, 1132a, 1132b. Here, the first incision part 1122c and the second incision part 1132c may be formed by cross-shaped incision lines 1122a, 1122b, 1132a, 1132b.

[0074] The opening pressures of the first discharge part 1122 and the second discharge part 132 may be provided with a difference from each other. At this time, the first discharge part 1122 and the second discharge part 132 may be formed of materials with different elastic degrees, and the opening pressures of the first discharge part 1122 and the second discharge part 132 may be provided with a difference from each other. At this time, the opening pressure of the first discharge part 1122 may be provided to be greater than the opening pressure of the second discharge part 132.

[0075] The first discharge part 1122 and the second discharge part 132 further include adhesive liquids 1122d and 1132d located on the first incision part 1122c and the second incision part 1132c, additionally seal the first incision part 1122c and the second incision part 1132c, and there may be a release of the adhesive force that seals the first incision part 1122c and the second incision part 1132c when the first incision part 1122c and the second incision part 1132c are opened by gas pressure.

[0076] Thereby, by more firmly sealing the first incision part 1122c and the second incision part 1132c via the adhesive liquids 1122d and 1132d, leakage of gas and electrolyte can be more effectively prevented at a pressure below a predetermined value between the first incision part 1122c of the first discharge part 1122 and the second incision part 1132c of the second discharge part 132.

[0077] Furthermore, a battery pack can be formed by electrically connecting a number of secondary batteries having the above-described configuration.

[0078] As described above, the present invention has been described in detail based on specific embodiments, but this is for specifically explaining the present invention, and the secondary battery according to the present invention is not limited thereto. Various implementations are possible by those having ordinary knowledge in the art within the technical idea of the present invention.

[0079] Also, the specific protection scope of the invention is clarified by the appended claims.

Explanation of Reference Numerals

[0080] S1, S2 Secondary battery 100 Battery case 110 Main body 111 Accommodating part 120 First gas pocket part 121 First collection space 122, 1122 First discharge part Cutting lines of 122a, 122b, 132a, 132b, 1122a, 1122b, 1132a, 1132b First cut portions of 122c, 1122c First through-hole 123 Second gas pocket portion 130 Second collection space 131 Second discharge portions 132, 1132 Second cut portions of 132c, 1132c Second through-hole 133 Gas sensor 150 Air pressure sensors 160, 170 Electrode assembly 200 Positive electrode 210 Negative electrode 220 Electrode 230 Separator 240 Electrode tap 250 Electrode lead 300 Adhesive liquid of 1122d, 1132d

Claims

1. An electrode assembly in which electrodes and a separator are alternately laminated, and a battery case that houses the electrode assembly, and includes the battery case a first gas pocket portion in which a first collection space for collecting internal gas of the battery case is formed, and a first discharge portion for discharging gas located in the first collection space is provided, and a second gas pocket portion in which a second collection space for collecting gas discharged from the first discharge portion of the first gas pocket portion is formed, and a second discharge portion for discharging gas located in the second collection space to the outside is provided, and includes a secondary battery further including a gas sensor provided inside the second gas pocket portion for measuring the presence or absence of gas generation or the gas component in the second collection space.

2. An electrode assembly in which electrodes and a separator are alternately laminated, and a battery case that houses the electrode assembly, and includes the battery case a first gas pocket portion in which a first collection space for collecting internal gas of the battery case is formed, and a first discharge portion for discharging gas located in the first collection space is provided, and a second gas pocket portion in which a second collection space for collecting gas discharged from the first discharge portion of the first gas pocket portion is formed, and a second discharge portion for discharging gas located in the second collection space to the outside is provided, and includes a secondary battery further including a pressure sensor provided inside at least one or more of the first gas pocket portion or the second gas pocket portion for measuring air pressure.

3. The first discharge portion is located on a first through hole penetrating between the first collection space and the second collection space, and controls the opening and closing of the first through hole, The second discharge portion is located on a second through hole penetrating between the second collection space and the outside of the battery case, and controls the opening and closing of the second through hole. The secondary battery according to claim 1 or 2.

4. The battery case includes a main body in which a housing portion for housing the electrode assembly is formed, The first gas pocket portion extends along a side surface of the main body such that the housing portion and the first collection space are connected, The second gas pocket portion is provided above the first gas pocket portion such that the second collection space and the first collection space are connected between the first through holes. The secondary battery according to claim 3.

5. The opening pressures of the first discharge portion and the second discharge portion are provided so as to have a difference from each other. The secondary battery according to claim 3 or 4.

6. The first discharge part and the second discharge part are formed of materials having different elastic moduli, and the opening pressures of the first discharge part and the second discharge part are provided so as to be different from each other. The secondary battery according to any one of claims 3 to 5.

7. The secondary battery according to claim 5, wherein the opening pressure of the first discharge part is provided to be greater than the opening pressure of the second discharge part.

8. The gas sensor senses the generation of carbon dioxide (CO ２ ), and the secondary battery according to claim 1.

9. The gas sensor of the secondary battery according to claim 1 generates at least one or more of a notification signal, a notification sound, or a notification light when gas is generated.

10. A battery pack including the secondary battery according to any one of claims 1 to 9.

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