Battery case and secondary battery

Abstract

The present invention relates to a battery case and a secondary battery, and more particularly to a battery case including a battery case cover and a gas adsorption unit housed inside the case, the gas adsorption unit being a gas adsorption pack that opens when the internal temperature of the case rises, and a secondary battery including the same. According to the present invention, gas generated inside a battery due to abnormal operation or degradation due to the battery's lifespan is quickly adsorbed by opening a gas adsorption pack filled with a gas adsorbent housed inside the case, without the need for an additional system or sensing device, thereby ensuring the stability of the battery, preventing deformation of the battery case, reducing the resistance of the battery, and allowing the secondary battery to operate even after the gas adsorption pack is opened.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2022 - 0040251 filed on March 31, 2022, and all the contents disclosed in the Korean Patent Application are incorporated herein by reference as part of this specification.

[0002] The present invention relates to a battery case and a secondary battery, and more particularly, to a battery case and a secondary battery that quickly adsorb gas generated by activation or degradation of a secondary battery through the opening of a gas adsorption pack accommodated inside the case without an additional system or sensing device, ensuring the stability of the battery, and further driving the secondary battery even after the gas adsorption pack is opened.

Background Art

[0003] A secondary battery is a rechargeable battery manufactured using a material in which the oxidation and reduction processes between current and substances can be repeated multiple times. That is, when a reduction reaction with respect to the material is performed by current, the battery is charged, and when an oxidation reaction with respect to the material is performed, electricity is discharged from the battery.

[0004] Generally, types of secondary batteries include nickel - cadmium batteries, nickel - metal hydride batteries, lithium secondary batteries, and lithium - ion polymer batteries. Such secondary batteries are not only used in small products such as digital cameras, P - DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools, and E - bikes, but also in large products that require high power such as electric vehicles and hybrid vehicles, as well as power storage devices for storing surplus generated power and renewable energy, or backup power storage devices.

[0005] The lithium secondary battery, as an example, is formed by laminating a cathode, a separator, and an anode, and charging and discharging are performed while the process of lithium ions being inserted (intercalated) into and removed (deintercalated) from the graphite electrode of the anode from the lithium metal oxide of the cathode is repeated. And these materials are selected in consideration of the battery life, charge and discharge capacity, temperature characteristics, stability, etc.

[0006] The lithium secondary battery is classified into a can-type secondary battery in which the electrode assembly is built into a metal can and a pouch-type secondary battery in which the electrode assembly is built into a pouch of an aluminum laminate sheet according to the shape of the battery case. The can-type secondary battery is classified into a cylindrical battery and a prismatic battery.

[0007] When the lithium secondary battery rises to a voltage above the operating voltage, the constituent materials are decomposed to generate flammable gas, or the battery deteriorates and gas is generated due to the collapse of the cathode structure. The gas generated in this way increases the resistance of the battery and raises the internal pressure of the battery. If left unattended, the battery may explode.

[0008] Generally, for prismatic and cylindrical secondary batteries, in order to ensure safety when gas is generated, a method of joining a safety vent to the cap plate, which is the upper plate of the battery, is mainly used. This safety device prevents the battery from exploding by safely discharging the internal gas when the internal temperature of the battery rises abnormally.

[0009] However, in the case of a pouch-type secondary battery, since the gas discharge is determined by the seal strength of the pouch without a separate safety device, there is a problem that it is difficult to open the pouch and discharge the gas when a specific temperature is accurately reached. Furthermore, even if the risk of explosion can be reduced by opening the pouch and discharging the gas, there still remains a problem that the secondary battery cannot be driven any further after the pouch is opened.

[0010] Therefore, there is a need to develop a means to improve the increase in internal temperature due to gas generation in a lithium secondary battery, as well as the resulting explosion, ignition, and inoperability of the battery, while ensuring battery stability without degrading various battery performances.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0012] In order to solve the problems of the prior art as described above, the present invention aims to provide a battery case that can delay the time when the battery case explodes due to gas and ensure battery stability by automatically opening and adsorbing the gas generated in the battery with a gas adsorption pack housed inside the battery case without the need for recognition work through an additional system or sensing device.

[0013] Furthermore, the present invention aims to provide a secondary battery including the battery case, an electrode assembly housed inside the battery case, and an electrolyte filled inside the battery case.

[0014] The above object and other objects of the present invention can all be achieved by the present invention described below.

Means for Solving the Problems

[0015] To achieve the above object, the present invention provides a battery case including a battery case cover and a gas adsorption part housed inside the case, wherein the gas adsorption part is characterized in that a gas adsorption pack is opened when the internal temperature of the case increases.

[0016] The gas adsorption part may preferably include a gas adsorption pack filled with a gas adsorbent and a shape memory alloy that bends when the internal temperature increases and penetrates the gas adsorption pack.

[0017] The shape memory alloy may preferably be at least one selected from the group consisting of nickel-titanium alloy (Ni-Ti), copper-zinc alloy (Cu-Zn), copper-cadmium alloy (Cu-Cd), nickel-aluminum alloy (Ni-Al), copper-zinc-aluminum alloy (Cu-Zn-Al), and copper-aluminum-nickel alloy (Cu-Al-Ni).

[0018] The shape memory alloy may preferably have a shape recovery temperature of 70 to 100°C.

[0019] The shape memory alloy may preferably have a one-way shape memory effect.

[0020] The gas adsorption part may preferably be attached to the inner wall of the battery case cover.

[0021] The gas adsorbent may preferably include at least one selected from the group consisting of a gas adsorbing molecular sieve, a gas adsorbing metal, and a gas adsorbing substance.

[0022] The gas adsorbing molecular sieve may preferably be at least one selected from the group consisting of silica gel, carbon fiber, porous carbon material, porous metal oxide, porous gel, and zeolite.

[0023] The gas adsorbing metal may preferably be at least one selected from the group consisting of nickel (Ni), platinum (Pt), palladium (Pd), calcium (Ca), strontium (Sr), barium (Ba), thallium (Tl), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), and tungsten (W).

[0024] The gas adsorbing substance is preferably at least one selected from the group consisting of BaTiO3, PB(Mg3Nb 2 / 3 )O3-PbTiO3 (PMN-PT), hafnium oxide (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, sodium hydroxide (NaOH), calcium hydroxide (Ca(OH)2), and potassium hydroxide (KOH).

[0025] The gas adsorption pack may preferably comprise at least one selected from the group consisting of an olefin resin, a fluororesin, and a polyamide resin.

[0026] The gas adsorption part is preferably installed such that a shape memory alloy is positioned between the inner wall of the battery case cover and the gas adsorption pack, or such that a shape memory alloy is positioned on the side surface of the gas adsorption pack located on the inner wall of the battery case cover.

[0027] The present invention also provides a secondary battery including the battery case, an electrode assembly housed inside the battery case, and an electrolyte filled inside the battery case.

[0028] In the secondary battery, preferably, the gas adsorption pack may be blocked from the outside air or may be in an unsealed state.

[0029] The secondary battery may preferably be a pouch-type battery.

Advantages of the Invention

[0030] According to the present invention, in a secondary battery, when the structure of the positive electrode collapses due to degradation caused by the battery life and gas is generated, or when an abnormal operating state such as overcharging or high-temperature exposure occurs, gas is generated while the internal electrolyte decomposes, thereby increasing the internal temperature of the battery. At this time, the gas adsorption pack housed inside the battery case is automatically opened to quickly adsorb the gas, ensuring the stability of the battery, preventing deformation of the battery case, and having the effect of reducing the resistance of the battery.

[0031] In addition, the battery case according to the present invention does not require an additional sensing device for checking the temperature, voltage, etc. of the battery, so the manufacturing process is simple, and there is an effect that malfunction due to errors in the sensing device does not occur.

[0032] Also, by reacting sensitively to changes in the internal temperature of the battery case, the stability is further improved and the battery case is not damaged, so there is an effect that the battery can be driven even after the gas adsorption pack is opened.

Brief Description of the Drawings

[0033] The following drawings attached to this specification illustrate embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description to be described later. Therefore, the present invention should not be construed as being limited to the matters described in such drawings.

Figure 1

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Figure 6

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Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0034] The inventors were researching a method for removing gas generated inside a secondary battery. When there is a gas adsorption pack filled with a gas adsorbent inside the battery case and a shape memory alloy that can bend when the internal temperature increases due to gas generation and pierce through the gas adsorption pack, the case deforms due to the temperature rise caused by the gas generated inside the battery case, and the gas can be removed before it leads to an explosion. Therefore, the stability of the battery is ensured, the resistance of the battery is reduced, and the battery case is not damaged. After the gas adsorption pack is opened, the battery cells are driven, and it is confirmed that the performance of the battery is ensured. Based on this, the inventors further advanced the research and completed the present invention.

[0035] Hereinafter, with reference to the accompanying drawings, embodiments that can be easily implemented by those having ordinary knowledge in the technical field to which the present invention pertains will be described in detail. However, when explaining in detail the operating principle of a preferred embodiment of the present invention, if it is determined that a specific explanation of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed explanation thereof will be omitted.

[0036] Also, the same reference numerals are used for parts having similar functions and operations throughout the drawings. In the entire specification, when a part is said to be "connected" to another part, this includes not only the case where they are "directly connected", but also the case where they are "indirectly connected" with other elements intervening therebetween. Further, saying that a certain component "includes" means that, unless otherwise stated to the contrary, it does not exclude other components and can further include other components.

[0037] The description of concretizing by limiting or adding components is applicable to all inventions without particular limitation and is not limited to a specific invention.

[0038] The battery case according to an embodiment of the present invention includes a battery case cover 10 and a gas adsorption part 20 housed inside the case. The gas adsorption part 20 is characterized in that when the internal temperature of the case rises, a gas adsorption pack 21 filled with a gas adsorbent is opened. In this case, by quickly adsorbing and removing the gas that caused the temperature rise, the stability of the battery can be ensured and the resistance of the battery can be reduced.

[0039] The gas adsorption part 20 may preferably include a gas adsorption pack 21 filled with a gas adsorbent and a shape memory alloy 22 that bends when the internal temperature rises and pierces through the gas adsorption pack.

[0040] The terms "secondary battery", "battery", and "battery cell" used in the present invention refer to those in which an electrode assembly is enclosed inside a battery case together with an electrolyte, unless otherwise specified. Further, secondary batteries, batteries, and / or battery cells can be connected in series to form a battery module, and a plurality of battery modules can be connected in parallel and / or in series according to the required charge and discharge capacity to form a battery pack.

[0041] In the present invention, the battery case cover may have an empty space inside, and may be formed to accommodate an electrode assembly and an electrolyte in such an internal space.

[0042] Hereinafter, the gas adsorption part 20 will be specifically described.

[0043] The gas adsorption part 20 may be attached to the inner wall of the battery case cover 10 as an example, and in such a case, it can have no influence on the charge and discharge of the secondary battery.

[0044] The gas adsorption part 20 may preferably be installed on the inner wall of the upper or lower cover, or both, with reference to the position of the accommodated electrode assembly 110. In such a case, there are advantages in that the generated gas can be adsorbed more quickly to rapidly lower the internal temperature, ensuring the stability of the battery, preventing deformation of the case, and reducing the resistance of the battery.

[0045] The gas adsorption part 20 may be attached to the upper part of the electrode assembly as an example, and in such a case, it can have no influence on the charge and discharge of the secondary battery.

[0046] The gas adsorption part 20 may be fixed to the inner wall of the battery case cover 10 or the upper part of the electrode assembly with a PET tape as an example. In such a case, there is an advantage in that it has no influence on the charge and discharge of the secondary battery and is not affected by the electrolyte.

[0047] The PET tape may be a tape in which a silicon-based adhesive is applied to a polyester film as an example.

[0048] The gas adsorption pack 21 may be similar to the outer shape of the case as an example, and may preferably be rectangular, but may also be amorphous with a freely changeable shape.

[0049] Inside the gas adsorption pack 21, a gas adsorbent capable of adsorbing gas is incorporated.

[0050] The gas generated inside the secondary battery can be, for example, a gas generated by the decomposition of the electrolyte or a gas generated by the collapse of the positive electrode structure during degradation due to the battery life.

[0051] The gas generated by the decomposition of the electrolyte can be, for example, oxygen, carbon monoxide (CO) and / or carbon dioxide (CO2), and the gas generated by the collapse of the positive electrode structure during degradation due to the battery life can be, for example, oxygen.

[0052] The gas adsorbent is not greatly limited in its type as long as it is a substance that can easily adsorb a gas generated in a large proportion inside the battery. Preferably, it can contain one or more selected from the group consisting of a gas-adsorbing molecular sieve, a gas-adsorbing metal, and a gas-adsorbing substance. In such a case, the gas inside the battery can be efficiently adsorbed, the stability of the battery can be ensured, the resistance of the battery can be reduced, and the deformation and explosion of the case can be prevented.

[0053] The gas-adsorbing molecular sieve may be, for example, one or more selected from the group consisting of silica gel, carbon fiber, a porous carbon material, a porous metal oxide, a porous gel, and zeolite.

[0054] The porous carbon material may be, for example, one or more selected from the group consisting of carbon molecular sieve and activated carbon.

[0055] The activated carbon may preferably be one or more selected from the group consisting of granular carbon, powdered carbon, formed carbon, and activated fiber.

[0056] The porous metal oxide may be, for example, one or more selected from the group consisting of silica gel, alumina, and molecular sieve.

[0057] The zeolite can be classified by its crystal structure, and as an example, it may be one or more selected from the group consisting of A-type zeolite, L-type zeolite, β-type zeolite, MFI-type zeolite, and faujasite-type zeolite.

[0058] The gas-adsorbing metal may be, for example, one or more selected from the group consisting of nickel (Ni), platinum (Pt), palladium (Pd), calcium (Ca), strontium (Sr), barium (Ba), thallium (Tl), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), and tungsten (W).

[0059] The gas-adsorbing substance may be, for example, one or more selected from the group consisting of BaTiO3, PB(Mg3Nb 2 / 3 )O3-PbTiO3 (PMN-PT), hafnia (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, sodium hydroxide (NaOH), calcium hydroxide (Ca(OH)2), and potassium hydroxide (KOH).

[0060] The gas-adsorbing pack 21 may be provided with a space part so as to accommodate a gas adsorbent, for example, and may be made of a material having a predetermined thickness that can be perforated or torn by a shape memory alloy.

[0061] The gas-adsorbing pack 21 may include, for example, one or more selected from the group consisting of olefin resins, fluorine resins, and polyamide resins, and in such a case, it can have no adverse effect on the electrolyte.

[0062] The olefin resin may include, for example, one or more selected from the group consisting of polypropylene, polyethylene, polyethylene acrylic acid, and polybutylene.

[0063] The polyamide resin may, for example, be one or more selected from the group consisting of polyamide 4.6, polyamide 6, polyamide 6.6, polyamide 6.10, polyamide 7, polyamide 8, polyamide 9, polyamide 11, polyamide 12, and MXD6.

[0064] The fluororesin may preferably be polytetrafluoroethylene (PTFE).

[0065] Generally, in order to remove the gas generated when a secondary battery is overcharged or when charge and discharge are repeated, a separate gas removal process is performed, and for this purpose, a separate sensing device is required. However, as shown in FIGS. 2 to 5, the present invention includes a gas adsorption part inside the case. The gas adsorption part includes a gas adsorption pack filled with a gas adsorbent and a shape memory alloy that bends when the internal temperature rises and penetrates the gas adsorption pack, so that it can react sensitively to the change in the internal temperature due to gas generation and quickly remove the gas. Therefore, the stability of the battery is greatly ensured, and the resistance of the battery can be reduced to improve the performance of the battery.

[0066] In addition, when gas is generated due to battery degradation, the battery may swell and there is a risk of explosion. However, such gas can also be removed by opening the gas adsorption pack, which can significantly reduce the load applied to the secondary battery.

[0067] In addition, if the case is partially damaged or opened to remove the gas, the stability of the battery is ensured, but the battery can no longer perform its function. However, the present invention has the advantage that the battery can be driven even after the gas adsorption pack is opened by adsorbing and removing the gas without damaging the case.

[0068] The shape memory alloy 22, for example, deforms at a predetermined angle to penetrate the gas adsorption pack and release the gas adsorbent so as to adsorb and remove the gas when the internal temperature rises due to the gas generated inside the case.

[0069] In this description, the release of the gas adsorbent means that a fluid containing a gas comes into contact with the gas adsorbent, and the gas adsorbent is discharged into the fluid or the fluid flows into the gas adsorbent. The fluid may be, for example, an electrolyte, an inert gas (e.g., N2, Ar, etc.), or vapor.

[0070] In this description, a shape memory alloy is an alloy that remembers its original shape and returns to its original shape even if it is deformed by heat or pressure. When a general metal is deformed, the bonds in the metal are broken or newly generated, but in a shape memory alloy, the bonds in the metal are retained as they are when deformed, and the deformation is released under specific conditions and returns to its original shape. After being deformed, when a shape memory alloy is heated again, it remembers the shape before the first deformation and returns to its original shape. At this time, the degree of deformation must be, for example, applied below a certain critical temperature, and as a specific example, it must be less than about 10%. Through "reheating", the shape memory alloy revives the crystal structure that it should preferentially adopt at a high temperature and the shape that matches it. Once a shape memory alloy remembers a certain shape, it has the property of returning to the shape before deformation when heated to an appropriate temperature even if it is deformed into various shapes. In order to have such a shape memory effect, a certain heat treatment is required. In the case of Nitinol, which is a nickel-titanium alloy (Ni-Ti), if it is made into a certain shape and left at a temperature of 400 to 500 °C for about 30 minutes while fixed, the alloy remembers this shape. Once remembered, no matter how many times it is deformed, it returns to its original shape just by heating it to a certain temperature or higher. This certain temperature is called the "shape recovery temperature". The shape recovery temperature can be set variously by changing the conditions.

[0071] The shape memory alloy 22 may, for example, be one or more selected from the group consisting of nickel-titanium alloy (Ni-Ti), copper-zinc alloy (Cu-Zn), copper-cadmium alloy (Cu-Cd), nickel-aluminum alloy (Ni-Al), copper-zinc-aluminum alloy (Cu-Zn-Al), and copper-aluminum-nickel alloy (Cu-Al-Ni). In this case, there is an effect of being sensitive to the rise in the temperature inside the secondary battery.

[0072] The shape memory alloy may, for example, have a shape recovery temperature of 70 to 100°C, preferably 75 to 90°C, more preferably 80 to 90°C. Within this range, before the occurrence of battery deformation such as the swelling phenomenon of the battery due to the rise in the internal temperature of the secondary battery, the shape memory alloy can bend to punch holes in the gas adsorption pack or tear it to ensure the stability of the battery.

[0073] To set the shape recovery temperature to 70 to 100°C, the shape memory alloy can be heat-treated, for example, at 70 to 100°C, preferably 75 to 90°C, more preferably 80 to 90°C for, for example, 15 to 40 minutes, preferably 20 to 35 minutes. Within this range, before the occurrence of battery deformation such as the swelling phenomenon of the battery due to the rise in the internal temperature of the secondary battery, the shape memory alloy can bend to pierce through the gas adsorption pack, thereby having the advantage of ensuring the stability of the battery.

[0074] The shape memory alloy may, for example, have a one-way shape memory effect. In this case, there are advantages of reducing the manufacturing cost and the installation space.

[0075] In this description, the one-way shape memory effect refers to the fact that when a shape memory alloy memorized in an appropriate shape is deformed at a low temperature and then heated to a certain temperature or higher, it returns to its original shape, but even if it is cooled to a low temperature again, it does not return to the deformed shape before the temperature was raised. In contrast, the two-way shape memory effect or reversible shape memory effect refers to simultaneously memorizing the shape at a high temperature and the shape at room temperature before the temperature was raised. This is a reversible operation in which two shapes are repeated through heating and cooling. In order to obtain the two-way shape memory effect, there are engineering problems such that the alloy must be subjected to special heat treatment or configured together with components such as springs.

[0076] The gas adsorption part 20 may, for example, be attached to the inner wall of the case cover. Thereby, it can react sensitively to changes in the internal temperature due to gas generation inside the battery 1. That is, when the internal temperature of the battery 1 rises slightly, the shape memory alloy can be bent immediately to make a hole in or tear the gas adsorption pack 21.

[0077] Also, the gas adsorption part 20 may, for example, be attached to the upper surface of the electrode assembly. In such a case, while not affecting the charge and discharge of the secondary battery, since the gas rising upward can be removed immediately even if the density is low, there is an advantage of providing higher stability.

[0078] Here, the shape memory alloy 22 is preferably located near the middle of the battery case cover 10, because when the battery 1 undergoes a swelling phenomenon in which it expands due to an increase in internal temperature, the volume expands most quickly near the middle, so there is an advantage that it can react more quickly.

[0079] The shape memory alloy 22 may, for example, be in the form of a thin film or an elongated shape. When the secondary battery operates at normal temperature, it is in a straight shape. When the internal temperature rises due to gas generation, at least one end bends to pierce through the gas adsorption pack 21 and open the gas adsorbent.

[0080] The shape memory alloy 22 may, for example, have a thickness that decreases towards the end or a shape with a pointed tip.

[0081] As shown in FIG. 8, the cross-section of the elongated shape memory alloy 22 can have various shapes and may, for example, be plate-shaped, circular, triangular, square, or pentagonal.

[0082] As shown in FIG. 10, the thin-film type shape memory alloy 22 can have various shapes and may, for example, be triangular, rhombic, pentagonal, or hexagonal.

[0083] For example, when the shape memory alloy 22 is heat-treated at a high temperature in a bent shape and then deformed into a straight shape at a low temperature and installed inside the battery case, if the secondary battery operates abnormally and gas is generated, causing the internal temperature to rise, the shape memory alloy bends to pierce through the gas adsorption pack 21, thereby releasing the gas adsorbent to adsorb and remove the gas, controlling overheating and fire of the battery, and preventing deformation of the case.

[0084] Hereinafter, the low-temperature shape of the shape memory alloy 22 is referred to as a deformed shape or a deformed state, and the fact that it returns to the shape before deformation at the shape recovery temperature is denoted as a restored shape or a restored state.

[0085] For example, the deformed and restored part of the shape memory alloy 22 can be composed of a shape with a pointed end. In this case, there is an effect that the gas adsorption pack 21 can be easily pierced through and the gas adsorbent can be easily opened.

[0086] The shape memory alloy 22 can, for example, consist of one of the structures shown in FIG. 9, and at the shape recovery temperature, one or both ends bend toward the gas adsorption pack 21 to form a restored shape. The restored shape memory alloy can puncture or tear the gas adsorption pack 21, through which the gas adsorbent is released to adsorb gas, thereby ensuring the stability of the battery.

[0087] The gas adsorption part can, for example, be installed such that the shape memory alloy is located between the inner wall of the case cover and the gas adsorption pack, or the shape memory alloy is located on the side surface of the gas adsorption pack located on the inner wall of the case cover. In such a case, it does not affect the charge and discharge of the secondary battery, and by being sensitive to the rise in the internal temperature of the battery, the stability of the battery is improved, and there is an effect of preventing deformation of the battery case.

[0088] When installed such that the shape memory alloy is located on the side surface of the gas adsorption pack located on the inner wall of the case cover, for example, the shape memory alloy can be installed on one or both side surfaces of the gas adsorption pack. In such a case, there is an effect that the gas adsorption pack can be opened more quickly to adsorb gas.

[0089] The gas adsorption pack and the shape memory alloy can, for example, be fixed with a PET tape, but are not limited thereto.

[0090] Also, the gas adsorption part can, for example, be installed to be located above the electrode assembly. In this case, it does not affect the charge and discharge of the secondary battery, and by being sensitive to the rise in the internal temperature of the battery, the stability of the battery is improved, and there is an effect of preventing deformation of the battery case.

[0091] The present invention can include the battery case, the electrode assembly housed inside the battery case, and the electrolyte filled inside the battery case.

[0092] The electrode assembly may be a jelly-roll type electrode assembly having a structure in which a separator is interposed between a long sheet-like positive electrode and a negative electrode and then wound, a stack type electrode assembly composed of unit cells having a structure in which a rectangular positive electrode and a negative electrode are laminated with a separator therebetween, a stack-folding type electrode assembly in which unit cells are wound by a long separation film, or a lamination-stack type electrode assembly in which unit cells are laminated with a separator therebetween and adhered to each other, etc., but is not limited thereto.

[0093] Further, the electrode assembly has electrode tabs (not shown) extending therefrom. As an example, a positive electrode tab extends from the positive electrode and a negative electrode tab extends from the negative electrode. Here, when the electrode assembly is configured in a state where a large number of positive electrodes and a large number of negative electrodes are laminated, the electrode tabs extend from the respective positive electrodes and negative electrodes. At this time, the electrode tabs are not directly exposed outside the case and can be connected to other components such as the electrode lead 130.

[0094] The electrode lead 130 is electrically connected in part to an electrode tab extending from the positive electrode or the negative electrode, respectively. Such an electrode lead has one end connected to the electrode tab and the other end exposed outside the case, and the other end exposed outside can function as an electrode terminal. Therefore, by connecting a charger, a load, etc. to the other end of such an electrode lead 130, the secondary battery can be charged and discharged. Further, an insulating film may be attached to a part of the upper and lower surfaces of the electrode lead to enhance the sealing degree with the battery case and at the same time ensure an electrically insulated state.

[0095] As an example, the positive electrode is manufactured by applying a positive electrode mixture containing a positive electrode active material on a positive electrode current collector and then drying. The positive electrode mixture may further selectively contain a binder, a conductive material, a filler, etc. as necessary.

[0096] The positive electrode current collector is manufactured, for example, with a thickness of 3 to 500 μm. Such a positive electrode current collector is not particularly limited as long as it does not induce a chemical change in the battery and has high conductivity. For example, it may be one or more selected from the group consisting of stainless steel, aluminum, nickel, titanium, fired carbon, surface-treated aluminum, and surface-treated stainless steel. The surface treatment may be, for example, surface treatment with one or more selected from the group consisting of carbon, nickel, titanium, and silver.

[0097] Also, the positive electrode current collector can, for example, form fine irregularities on its surface to enhance the adhesive force of the positive electrode active material, and various forms such as films, sheets, foils, nets, porous bodies, foams, and non-woven bodies are possible.

[0098] The positive electrode active material is a substance capable of causing an electrochemical reaction. As a lithium transition metal oxide, it contains two or more transition metals. For example, lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), etc., which are layered compounds substituted with one or two or more transition metals; lithium manganese oxide substituted with one or two or more transition metals; lithium nickel-based oxides represented by the chemical formula LiNi 1-y M y O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn, or Ca, and contains one or more of the above elements, and 0.01 ≦ y ≦ 0.7); Li 1+z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2, Li 1+z Ni 0.4 Mn 0.4 Co 0.2 O2, etc., such as Li 1+z Ni b Co 1-(b+c+d) M d O (2-e) A e(Here, -0.5 ≤ z ≤ 0.5, 0.1 ≤ b ≤ 0.8, 0.1 ≤ c ≤ 0.8, 0 ≤ d ≤ 0.2, 0 ≤ e ≤ 0.2, b + c + d < 1, M = Al, Mg, Cr, Ti, Si or Y, and A = F, P or Cl) lithium nickel cobalt manganese composite oxide represented by; chemical formula Li 1+x M 1-y M y PO 4-z X z (Here, M = transition metal, preferably Fe, Mn, Co or Ni, M = Al, Mg or Ti, X = F, S or N, -0.5 ≤ x ≤ +0.5, 0 ≤ y ≤ 0.5, 0 ≤ z ≤ 0.1) olivine-type lithium metal phosphate represented by, and the like, but not limited thereto.

[0099] The conductive material is added, for example, in an amount of 1 to 30% by weight based on the total weight of the mixture containing the positive electrode active material, the conductive material and the binder. Such a conductive material is not particularly limited as long as it has conductivity without inducing chemical changes in the battery. For example, graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black; conductive fibers such as carbon fibers and metal fibers; metal powders such as aluminum powder and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives and carbon fluoride; One or more selected from the group consisting of may be used.

[0100] The binder is a component that helps the binding of the active material and the conductive material and the like and the binding to the current collector, and is added, for example, in an amount of 1 to 30% by weight based on the total weight of the mixture containing the positive electrode active material, the conductive material and the binder.

[0101] The binder may be, for example, one or more selected from the group consisting of polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, and fluororubber.

[0102] The filler is selectively used as a component for suppressing the expansion of the electrode, does not induce chemical changes in the battery, and is not particularly limited as long as it is a fibrous material. For example, olefin polymers such as polyethylene and polypropylene; and / or fibrous substances such as glass fiber and carbon fiber are used.

[0103] The negative electrode is manufactured, for example, by applying a negative electrode mixture containing a negative electrode active material onto a negative electrode current collector and then drying it. The negative electrode mixture may contain components such as a conductive material, a binder, and a filler as described above, if necessary.

[0104] The negative electrode current collector is manufactured to have a thickness of, for example, 3 to 500 μm. Such a negative electrode current collector is not particularly limited as long as it does not induce chemical changes in the battery and has high conductivity. For example, one or more selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, fired carbon, surface-treated copper, surface-treated stainless steel, and an aluminum-cadmium alloy may be used. The surface treatment may be, for example, surface-treated with one or more selected from the group consisting of carbon, nickel, titanium, and silver.

[0105] Also, similar to the positive electrode current collector, the negative electrode current collector can also form fine irregularities on the surface to strengthen the binding force of the negative electrode active material, and may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a non-woven fabric body.

[0106] The negative electrode active material is, for example, carbon such as graphitizable carbon and graphite-based carbon; Li x Fe2O3(0≦x≦1), Li x WO2(0≦x≦1), Sn x Me 1-x Me y O z (Me: Mn, Fe, Pb, Ge; Me: Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0≦x≦1; 1≦y≦3; 1≦z≦8) and other metal composite oxides; lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, Sb2O6, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5; conductive polymers such as polyacetylene; and one or more selected from the group consisting of Li-Co-Ni-based materials may be used.

[0107] The binder, conductive material, and components added as necessary are the same as those described for the positive electrode. In some cases, a filler may be selectively added as a component for suppressing the expansion of the negative electrode. Such a filler does not induce chemical changes in the battery and, if it is a fibrous material, is not particularly limited. For example, olefin-based polymers such as polyethylene and polypropylene; and / or fibrous substances such as glass fibers and carbon fibers are used.

[0108] In addition, the negative electrode mixture may further contain other components such as a viscosity regulator and an adhesion promoter, either selectively or in a combination of two or more.

[0109] The viscosity regulator is a component that adjusts the viscosity of the electrode mixture so that the mixing process of the electrode mixture and the coating process on its current collector are facilitated. For example, it may be added at 1 to 30% by weight based on the total weight of the negative electrode active material, conductive material, binder, and filler. Examples of such a viscosity regulator include, but are not limited to, carboxymethyl cellulose and / or polyvinylidene fluoride. In some cases, the above-described solvent can also serve as a viscosity regulator.

[0110] The adhesion promoter is an auxiliary component added to improve the adhesion of the active material to the current collector, and may be added in an amount of 10% by weight or less with respect to the binder, or more than 0% by weight and up to 10% by weight. Examples include oxalic acid, adipic acid, formic acid, acrylic acid derivatives, itaconic acid derivatives, and the like.

[0111] The separator is located between the positive electrode and the negative electrode, electrically insulates the positive electrode and the negative electrode from each other, and can be formed in the form of a porous membrane so that lithium ions and the like can pass through each other between the positive electrode and the negative electrode. Such a separator can be composed of, for example, a porous membrane using polyethylene, polypropylene, or a composite film thereof.

[0112] The electrolyte is for moving lithium ions generated by the electrochemical reaction of the electrodes during charge and discharge of the secondary battery, and may be an electrolytic solution, a solid electrolyte, and / or a semi-solid electrolyte.

[0113] The electrolytic solution may be, for example, a non-aqueous electrolytic solution containing a lithium salt.

[0114] The non-aqueous electrolytic solution containing a lithium salt is composed of, for example, an electrolytic solution and a lithium salt. The electrolytic solution can include, for example, a non-aqueous organic solvent, an organic solid electrolyte, an inorganic solid electrolyte, and the like.

[0115] As an example, the non-aqueous organic solvent may be an aprotic organic solvent. Specifically, it may be at least one selected from the group consisting of N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran (franc), 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triphosphate ester, trimethoxymethane, dioxolane derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ether, methyl propionate, and ethyl propionate.

[0116] As an example, for the organic solid electrolyte, at least one selected from the group consisting of a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, a polyaditation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, and a polymer containing an ionic dissociation group may be used.

[0117] As an example, the inorganic solid electrolyte may be at least one selected from the group consisting of a nitride, a halide, and a sulfate of Li. Specifically, it may be at least one selected from Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, and Li3PO4-Li2S-SiS2.

[0118] The lithium salt is a substance that is easily soluble in the non-aqueous electrolyte. As an example, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10, one or more selected from the group consisting of LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, (CF3SO6)2NLi, lithium chloroborane, lithium lower aliphatic carboxylate, lithium 4-phenylborate, and imide may be used.

[0119] In addition, for the purpose of improving charge-discharge characteristics, flame retardancy, etc., as an example, one or more selected from the group consisting of pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, triamide hexaphosphate, nitrobenzene derivative, sulfur, quinoneimine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, and aluminum trichloride may be added to the non-aqueous electrolyte.

[0120] In addition, for imparting non-flammability, as an example, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride can be further included in the non-aqueous electrolyte, and for improving high-temperature storage characteristics, carbon dioxide gas can be further included, and FEC (Fluoro-Ethylene Carbonate), PRS (Propene sultone), etc. can be further included. Preferably, a lithium salt such as LiPF6, LiClO4, LiBF4, LiN(SO2CF3)2, etc. is added to a mixed solvent of a cyclic carbonate of EC or PC which is a high-dielectric constant solvent and a linear carbonate of DEC, DMC or EMC which is a low-viscosity solvent to produce a lithium salt-containing non-aqueous electrolyte.

[0121] The solid electrolyte may be, for example, one or more selected from the group consisting of an organic solid electrolyte, an inorganic solid electrolyte having ion conduction activity, and a composite solid electrolyte.

[0122] The semi-solid electrolyte may be, for example, a gel-like electrolyte obtained by adding a polymer additive to an electrolyte composed of a lithium salt, an additive, and an organic solvent.

[0123] The polymer additive may be, for example, one or more selected from the group consisting of POE (Polyethylene oxide) and PTFE (Polytetrafluoroethylene).

[0124] The electrode assembly includes electrode tabs. The electrode tabs are respectively connected to the positive electrode and the negative electrode of the electrode assembly, protrude to the outside on one side from the electrode assembly, and form a path through which electrons can move between the inside and the outside of the electrode assembly.

[0125] An electrode lead is connected to the electrode tab of the electrode assembly by spot welding or the like. And a part of the electrode lead is surrounded by an insulating portion. The insulating portion is limited to be located at a sealing portion where the upper case and the lower case of the battery case are heat-sealed, and adheres the electrode lead to the battery case. And it prevents the electricity generated from the electrode assembly from flowing to the battery case through the electrode lead, and maintains the sealing of the battery case. Therefore, such an insulating portion is manufactured from a non-conductive insulator having poor electrical conductivity.

[0126] As the insulating portion, an insulating tape that easily adheres to the electrode lead and has a relatively thin thickness is often used, but it is not limited thereto, and various members can be used as long as they can insulate the electrode lead.

[0127] One end of the electrode lead is connected to the electrode tab, and the other end protrudes to the outside of the electric case respectively. That is, the electrode lead includes a positive electrode lead with one end connected to the positive electrode tab and extending in the direction in which the positive electrode tab protrudes, and a negative electrode lead with one end connected to the negative electrode tab and extending in the direction in which the negative electrode tab protrudes. On the other hand, both the positive electrode lead and the negative electrode lead have the other end protruding to the outside of the battery case. Thereby, the electricity generated inside the electrode assembly can be supplied to the outside. Also, since the positive electrode tab and the negative electrode tab protrude in various directions respectively, the positive electrode lead and the negative electrode lead can also extend in various directions respectively.

[0128] The battery case can, for example, be composed of a laminated sheet structure of an inner layer / metal layer / external layer.

[0129] Since the inner layer is in direct contact with the electrode assembly, it must have insulation and electrolyte resistance. Also, for sealing with the outside, the sealing property, that is, the sealing part where the inner layers are thermally bonded to each other, must have excellent thermal bonding strength. As a material for such an inner layer, for example, one or more selected from the group consisting of polyolefin resins such as polypropylene, polyethylene, polyethylene acrylic acid, and polybutylene, which are excellent in chemical resistance and have good sealing properties, polyurethane resins, and polyamide resins may be used, but are not limited thereto. Polypropylene, which is excellent in mechanical physical properties such as tensile strength, rigidity, surface hardness, and impact resistance, and chemical resistance, is preferable.

[0130] The metal layer is in contact with the inner layer and corresponds to a barrier layer that prevents moisture and various gases from penetrating from the outside into the inside of the battery. Such a metal layer can, for example, use one or more selected from the group consisting of aluminum, aluminum alloys, copper, and iron alloys such as stainless steel, which are light and have excellent formability.

[0131] Also, an external layer is provided on the other side of the metal layer. The external layer can use a heat-resistant polymer that is excellent in tensile strength, moisture permeation prevention, and air permeation prevention so as to protect the electrode assembly and ensure heat resistance and chemical resistance. For example, polyamide or polyethylene terephthalate can be used, but is not limited thereto.

[0132] The secondary battery may preferably be a pouch-type battery. In this case, it can adsorb the gas generated inside the battery to prevent the risk of gas explosion or fire, and it has the advantage of being able to realize various sizes and shapes and having a high energy density.

[0133] As an example, in the secondary battery, the gas adsorption pack may be blocked from the outside air or may be opened. That is, before the battery operates normally or deteriorates due to its lifespan, the gas adsorption pack is in a state of being blocked from the outside air. When the battery deteriorates due to its lifespan or abnormal operation of the battery generates gas, the gas adsorption pack is opened and the gas adsorbent is released, thereby absorbing and removing the gas to ensure the stability of the battery, improving the performance of the battery by reducing the resistance of the battery, and having the advantage that the battery can be driven even after the gas adsorption pack is opened. Conventionally, when gas is generated inside the battery, a hole is made in the battery case to discharge and remove the gas. In such a case, there is a problem that the electrolyte and the like flow out from the battery case with the hole, and the battery cannot be driven any further.

[0134] A plurality of secondary batteries according to the present invention can be stacked in the vertical or horizontal direction to form a battery module. In this case, gas generated inside the battery case due to abnormal operation of the battery can be easily removed, and there is an effect that the battery can be driven even after the gas is removed.

[0135] Also, a plurality of the battery modules can be stacked in the vertical or horizontal direction to form a battery pack. In this case, gas generated inside the battery case due to abnormal operation of the battery can be easily removed, and there is an effect that the battery can be driven even after the gas is removed.

[0136] In the present invention, as an example, the manufacturing method of the secondary battery includes a step of applying a positive electrode active material slurry obtained by dissolving a positive electrode active material in a solvent to a positive electrode current collector, and applying a negative electrode active material slurry obtained by dissolving a negative electrode active material in a solvent to a negative electrode current collector to manufacture a positive electrode and a negative electrode; a step of interposing a separator between the manufactured positive electrode and negative electrode and laminating them to form a unit cell; a step of laminating the formed unit cells with each other to form an electrode assembly; and a step of accommodating the formed electrode assembly in a case having a gas adsorption portion attached to the inner wall of the case cover and injecting an electrolyte.

[0137] As another example, a method for manufacturing a secondary battery includes: applying a positive electrode active material slurry obtained by dissolving a positive electrode active material in a solvent to a positive electrode current collector, and applying a negative electrode active material slurry obtained by dissolving a negative electrode active material in a solvent to a negative electrode current collector to manufacture a positive electrode and a negative electrode; interposing a separator between the manufactured positive electrode and negative electrode and laminating them to form a unit cell; laminating the formed unit cells to each other to form an electrode assembly; installing the electrode assembly such that a gas adsorption part is located above the formed electrode assembly; and housing the electrode assembly provided with the gas adsorption part in a case and injecting an electrolyte.

[0138] Embodiments of the present invention will be described in detail based on the drawings.

[0139] FIG. 2 is a side view showing a gas adsorption part 20 housed inside a battery case cover 10 filled with an electrode assembly 110 and an electrolyte 120 in a battery 1 according to an embodiment of the present invention.

[0140] The gas adsorption part 20 is attached to the inner wall of the battery case cover 10, and a shape memory alloy 22 is installed between the inner wall of the case cover and the gas adsorption pack 21 in the gas adsorption part 20.

[0141] FIG. 3 is a top view showing the gas adsorption part 20 housed inside a battery case cover 10 according to an embodiment of the present invention. Specifically, a shape memory alloy 22 is installed between the inside of the case cover and the gas adsorption pack 21.

[0142] FIG. 4 is a side view showing a gas adsorption part 20 housed inside a battery case cover 10 filled with an electrode assembly 110 and an electrolyte 120 in a battery 1 according to an embodiment of the present invention.

[0143] A gas adsorption part 20 is attached to the inner wall of the battery case cover 10, and a shape memory alloy 22 is installed on one side surface of a gas adsorption pack 21 in the gas adsorption part 20. The gas adsorption part 20 can also have the shape memory alloy 22 installed on both side surfaces of the gas adsorption pack 21.

[0144] FIG. 5 is a view showing from above the gas adsorption part 20 accommodated inside the battery case cover 10 according to an embodiment of the present invention. Specifically, a gas adsorption pack 21 is located inside the case cover, and a shape memory alloy 22 is located on one side surface of the gas adsorption pack 21. The gas adsorption part 20 can also have the shape memory alloy 22 installed on both side surfaces of the gas adsorption pack 21.

[0145] FIG. 6 is a diagram for explaining the change of the gas adsorption part 20 due to the rise in the internal temperature caused by gas generation in the secondary battery 1 according to a preferred embodiment of the present invention.

[0146] Referring to FIG. 6 and explaining, as described above, when the internal temperature rises due to gas generation, the shape memory alloy 22 bends into a predetermined shape toward the gas adsorption pack 21 and pierces through the gas adsorption pack 21. As a result, the accommodated gas adsorbent is released, so that overheating and fire of the battery can be controlled, and deformation of the case can be prevented.

[0147] FIG. 7 is a diagram for explaining the shape memory alloy 22 according to an embodiment of the present invention and the state in which its end is formed to be pointed.

[0148] Referring to FIG. 7 and explaining, the shape memory alloy 22 has a shape in which the thickness becomes thinner toward the end and the tip is pointed. In such a case, it is possible to more easily make a hole in or tear the gas adsorption pack 21.

[0149] FIG. 8 is a diagram for explaining the cross section of the shape memory alloy 22 according to an embodiment of the present invention, and is an enlarged view showing the cross section of the A-A section in FIG. 7.

[0150] The cross-section of the shape memory alloy 22 can have various shapes as shown in FIG. 8.

[0151] In FIG. 8(a), a plate-shaped cross-sectional shape is shown. In FIG. 8(b), a circular cross-sectional shape is shown. In FIG. 8(c), a square cross-sectional shape is shown. In FIG. 8(d), a triangular cross-sectional shape is shown. In addition, the cross-sectional shape of the shape memory alloy 22 may be changed to various shapes for implementation.

[0152] FIG. 9 shows perspective views of the shape memory alloy 22 before and after deformation.

[0153] Referring to FIG. 9(a), the shape memory alloy 22 is generally a thin cylindrical shape, becoming thinner towards the right end and having a pointed shape. At normal temperature, it is in a linearly deformed state. However, since it is restored to its pre-deformed shape within the shape recovery temperature range, the right end bends. The left end of the shape memory alloy 22 that does not bend within the shape recovery temperature range has a planar shape, while the right end that bends within the shape recovery temperature range has a pointed shape.

[0154] Referring to FIG. 9(b), the shape memory alloy 22 is generally a thin cylindrical shape, becoming thinner towards both ends and having a pointed shape. At normal temperature, it is in a linearly deformed state. However, when the temperature rises above the shape recovery temperature, since it is restored to its pre-deformed shape, both ends bend in the same direction.

[0155] Referring to FIG. 9(c), the shape memory alloy 22 is generally a thin and flat square columnar shape, becoming thinner towards the right end and having a pointed shape. At normal temperature, it is in a linearly deformed state. However, when the temperature rises above the shape recovery temperature, since it is restored to its pre-deformed shape, the right end bends. The left end of the shape memory alloy 22 that does not bend above the shape recovery temperature has a planar shape, while the right end that bends above the shape recovery temperature has a pointed shape.

[0156] FIG. 10 shows various shapes of the thin-film type shape memory alloy 22. Specifically, in FIG. 10(a), the shape memory alloy 22 is triangular, in FIG. 10(b), the shape memory alloy 22 is rhombic, in FIG. 10(c), the shape memory alloy 22 is pentagonal, and in FIG. 10(d), the shape memory alloy 22 is hexagonal.

Description of Signs

[0157] 1 Secondary battery 10 Battery case cover 20 Gas adsorption part 21 Gas adsorption pack 22 Shape memory alloy 110 Electrode assembly 120 Electrolyte 130 Electrode lead

Claims

**Claim 1**: A battery case for housing an electrode assembly and an electrolyte therein, comprising a battery case cover and a gas adsorption part housed inside the case, wherein the gas adsorption part includes a gas adsorption pack filled with a gas adsorbent and a shape memory alloy that bends when the internal temperature increases and pierces through the gas adsorption pack, and the gas adsorption part is characterized in that when the internal temperature of the case increases, the gas adsorption pack is opened. A battery case. **Claim 2** The battery case according to claim 1, wherein the shape memory alloy is one or more selected from the group consisting of nickel-titanium alloy (Ni-Ti), copper-zinc alloy (Cu-Zn), copper-cadmium alloy (Cu-Cd), nickel-aluminum alloy (Ni-Al), copper-zinc-aluminum alloy (Cu-Zn-Al), and copper-aluminum-nickel alloy (Cu-Al-Ni). **Claim 3** The battery case according to claim 1, wherein the shape memory alloy has a shape recovery temperature of 70 to 100°C. **Claim 4** The battery case according to claim 1, wherein the shape memory alloy has a one-way shape memory effect. **Claim 5** The battery case according to claim 1, wherein the gas adsorption part is attached to the inner wall of the battery case cover. **Claim 6** The battery case according to claim 1, wherein the gas adsorbent includes one or more selected from the group consisting of a gas adsorbing molecular sieve, a gas adsorbing metal, and a gas adsorbing substance. **Claim 7** The battery case according to claim 6, wherein the gas adsorbing molecular sieve is one or more selected from the group consisting of silica gel, carbon fiber, porous carbon material, porous metal oxide, porous gel, and zeolite. **Claim 8** The battery case according to claim 6, wherein the gas adsorbing metal is one or more selected from the group consisting of nickel (Ni), platinum (Pt), palladium (Pd), calcium (Ca), strontium (Sr), barium (Ba), thallium (Tl), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), and tungsten (W). **Claim 9** The gas adsorbent is BaTiO ３ , PB(Mg ３ Nb ２／３ )O ３ -PbTiO ３ (PMN-PT), hafnia (HfO ２ ), SrTiO ３ , SnO ２ , CeO ２ , MgO, NiO, CaO, ZnO, ZrO ２ , Y ２ O ３ , Al ２ O ３ , TiO ２ , sodium hydroxide (NaOH), calcium hydroxide (Ca(OH) ２ ) and potassium hydroxide (KOH), and is characterized by being one or more selected from the group consisting of: The battery case according to claim 6. **Claim 10** The battery case according to claim 1, wherein the gas adsorption pack comprises one or more selected from the group consisting of an olefin resin, a fluororesin, and a polyamide resin.

11. The battery case according to claim 1, wherein the gas adsorption part is installed such that a shape memory alloy is positioned between the inner wall of the battery case cover and the gas adsorption pack, or such that a shape memory alloy is positioned on the side surface of the gas adsorption pack positioned on the inner wall of the battery case cover.

12. A secondary battery comprising the battery case according to any one of claims 1 to 11, an electrode assembly housed inside the battery case, and an electrolyte filled inside the battery case.

13. The secondary battery according to claim 12, wherein in the secondary battery, the gas adsorption pack is blocked from the outside air or is in an unsealed state.

14. The secondary battery according to claim 12, wherein the secondary battery is a pouch-type battery.

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