Secondary battery and electric device

Abstract

The present application discloses a secondary battery and an electric device. The secondary battery comprises a battery body and a casing for accommodating the battery body, wherein the battery body comprises a positive electrode sheet, an electrolyte, and a negative electrode sheet; a pouch is arranged between the battery body and the casing, the pouch is provided with powder of a hydrogen storage alloy, and the hydrogen absorption pressure of the hydrogen storage alloy is 0.3 MPa-0.5 MPa.

Description

Secondary batteries and electrical equipment

[0001] Priority information

[0002] This application claims priority and benefit to patent application 202510124928.9, filed with the China National Intellectual Property Administration on January 26, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of secondary batteries, specifically relating to a secondary battery and an electrical device. Background Technology

[0004] Secondary batteries are widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power plants, as well as in many fields such as power tools, electric bicycles, electric motorcycles, electric cars, military equipment, and aerospace.

[0005] As is well known, the thermal runaway problem of secondary batteries is very important. When a secondary battery experiences thermal runaway, it can be triggered by a variety of factors, and the proportion of gas produced during thermal runaway is large. Some of the produced gases can also act as combustion gases, which can lead to more serious runaway consequences or open flames that may further induce other runaway events. Summary of the Invention

[0006] In view of the technical problems existing in the background art, this application provides a secondary battery, which aims to reduce the occurrence of thermal runaway in secondary batteries.

[0007] To achieve the above objectives, the first aspect of this application proposes a secondary battery, which includes a battery body and a casing for housing the battery body. The battery body includes a positive electrode, an electrolyte, and a negative electrode. A plastic sealing bag is provided between the battery body and the casing, and the plastic sealing bag contains hydrogen storage alloy powder. The hydrogen absorption pressure of the hydrogen storage alloy is 0.3 MPa-0.5 MPa.

[0008] This application includes at least the following beneficial effects: The secondary battery of this application includes a hydrogen storage alloy, which can absorb hydrogen generated by the battery at 0.3MPa-0.5MPa. Moreover, the hydrogen storage alloy is in powder form, with a large contact area with the gas, which can rapidly absorb the flammable hydrogen gas inside the secondary battery before thermal runaway, thereby reducing the risk of thermal runaway of the secondary battery.

[0009] In some embodiments, the volume average particle size Dv50 of the hydrogen storage alloy is 2 μm-25 μm. This reduces the risk of thermal runaway in the secondary battery.

[0010] In some embodiments, the volume average particle size Dv50 of the hydrogen storage alloy is 2 μm-10 μm. This reduces the risk of thermal runaway in the secondary battery.

[0011] In some embodiments, the BET specific surface area of ​​the hydrogen storage alloy is 1 m². 2 / g-10m 2 / g. This can reduce the risk of thermal runaway in secondary batteries.

[0012] In some embodiments, the BET specific surface area of ​​the hydrogen storage alloy is 5 m². 2 / g-10m 2 / g. This can reduce the risk of thermal runaway in secondary batteries.

[0013] In some embodiments, the air permeability of the plastic-sealed bag is 100s / 100mL-1000s / 100mL.

[0014] In some embodiments, the air permeability of the plastic-sealed bag is 100s / 100mL-500s / 100mL.

[0015] In some embodiments, the material of the plastic-sealed bag includes at least one of polyethylene, polypropylene, EPDM rubber, or nitrile rubber.

[0016] In some embodiments, the amount of hydrogen storage alloy added to the secondary battery is 0.005 g / Ah to 2.4 g / Ah.

[0017] In some embodiments, the amount of hydrogen storage alloy added to the secondary battery is 0.04 g / Ah to 0.8 g / Ah.

[0018] In some embodiments, the negative electrode sheet includes a negative current collector and an interface modification layer disposed on at least one side of the negative current collector, the interface modification layer including an adhesive and a conductive agent.

[0019] In some embodiments, the thickness of the interface modification layer is 0.5 μm-5 μm.

[0020] In some embodiments, the electrolyte includes a solvent, which includes at least one of an ether solvent or an ester solvent.

[0021] In some embodiments, the solvent includes an ether solvent, which includes at least one of 1,2-dimethoxypropane, dimethoxymethane, ethylene glycol dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, pentaethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, or 1,3-dioxopentane.

[0022] In some embodiments, the hydrogen storage alloy includes magnesium-based alloys, titanium-based alloys, or LaNi alloys. y M z At least one of the following, wherein M includes at least one of Zr, Mn, Mg, Zn, Al, Ti, Fe, Cu, Co, Bi or Ca, 2≤y≤9, 0≤z≤5, and 7≤y+z≤9. This can reduce the risk of thermal runaway in secondary batteries.

[0023] In some embodiments, the secondary battery satisfies at least one of the following conditions:

[0024] The magnesium-based alloy and / or the titanium-based alloy contain iron; M includes at least one of Ti, Mn, Mg, Zr, Bi, or Fe; the titanium-based alloy includes TiNi. 0.5 Fe 0.5 Ti2Ni 0.5 Fe 0.5 At least one of the following; the magnesium alloy includes Mg2Ni 0.5 Fe 0.5 Mg2Al 0.5 Fe 0.5 Mg2Cr 0.5 Fe 0.5 or Mg2Te 0.5 Fe 0.5 At least one of them. This can reduce the risk of thermal runaway in secondary batteries.

[0025] In some embodiments, the hydrogen storage alloy comprises LaNi 6.2 Mg 0.2 Ti 0.8 LaNi 5.5 Mn 0.6 Fe 0.4 Bi 0.5 LaNi 7.5 Mn 0.2 Fe 0.4 Bi 0.9 LaNi2Ti 3.5 Fe 0.4 Zr 0.5 Bi0.6 LaNi9, LaNi7, TiNi 0.5 Fe 0.5 or Mg2Ni 0.5 Fe 0.5 At least one of them. This can reduce the risk of thermal runaway in secondary batteries.

[0026] In some embodiments, the battery body includes: an electrode assembly including the positive electrode and the negative electrode, the electrode assembly being housed within the housing, with a gap formed between the electrode assembly and the housing; an electrolyte including an electrolyte solution, the electrolyte solution being housed within the housing, a portion of the electrolyte solution being immersed in the electrode assembly, and a portion of the electrolyte solution being housed in a portion of the gap; and a gas storage structure housed within the housing, the gas storage structure being at least partially located in another portion of the gap, at least a portion of the gas storage structure being the hydrogen storage alloy.

[0027] In some embodiments, the housing includes a first wall and a second wall disposed opposite to each other, the first wall supporting the electrode assembly, and at least a portion of the gap being formed between the second wall and the electrode assembly, with at least a portion of the gas storage structure disposed between the electrode assembly and the second wall.

[0028] In some embodiments, a first insulating element is provided between the second wall and the electrode assembly; the gas storage structure is disposed between the first insulating element and the second wall, and / or the gas storage structure is disposed between the first insulating element and the electrode assembly.

[0029] In some embodiments, the second wall faces one side of the first insulator, and / or the first insulator faces one side of the second wall and is connected to the gas storage structure, and / or the electrode assembly faces one side of the first insulator, and / or the first insulator faces one side of the electrode assembly and is connected to the gas storage structure.

[0030] In some embodiments, a tab space is formed between the first insulating member and the electrode assembly, the tab space accommodating the tab, and at least a portion of the gas storage structure is disposed within the tab space.

[0031] In some embodiments, the electrode space includes: a folded electrode region accommodating the electrode and a void region located around the folded electrode region, at least a portion of the gas storage structure being disposed in the folded electrode region, and / or the void region.

[0032] In some embodiments, the gas storage structure is provided in the gap between adjacent electrodes within the electrode tab region, and / or in the gap between the electrode tab and the outer casing.

[0033] In some embodiments, the first insulating member has a receiving cavity that is open to one side of the second wall and / or to one side of the electrode assembly to receive the gas storage structure, and the receiving cavity is in communication with the gap.

[0034] In some embodiments, the first insulating member includes a limiting portion that protrudes toward the electrode assembly, and the accommodating cavity is formed in the limiting portion.

[0035] In some embodiments, the second wall is provided with an explosion-proof element configured to rupture when the pressure inside the housing reaches a set condition to release gas from the housing, and the first insulating element has a connecting portion for connecting the internal space of the housing with the explosion-proof element, and at least a portion of the gas storage structure is disposed in the connecting portion.

[0036] In some embodiments, the connecting portion is configured as a connecting groove formed on the first insulating member, the connecting groove extending along the side surface of the first insulating member facing the electrode assembly to the side surface of the first insulating member opposite to the electrode assembly.

[0037] In some embodiments, the housing has a third wall that is connected to the first wall and the second wall, and at least a portion of the gas storage structure is disposed between the third wall and the electrode assembly.

[0038] In some embodiments, a second insulating element is provided between the third wall and the electrode assembly, and the gas storage structure is disposed between the second insulating element and the third wall, and / or the gas storage structure is disposed between the second insulating element and the electrode assembly.

[0039] In some embodiments, the third wall faces the side surface of the second insulator, and / or the side surface of the second insulator facing the third wall is connected to the gas storage structure, and / or the electrode assembly faces the side surface of the second insulator, and / or the side surface of the second insulator facing the electrode assembly is connected to the gas storage structure.

[0040] In some embodiments, the second insulating member has a receiving cavity that is open to the side facing the third wall and / or to the side facing the electrode assembly to receive the gas storage structure, and the receiving cavity is in communication with the gap.

[0041] In some embodiments, the second insulating member includes a limiting portion that protrudes toward the electrode assembly, and the accommodating cavity is formed in the limiting portion.

[0042] In some embodiments, a tab space is formed between the second insulating member and the electrode assembly, the tab space accommodating the tab, and at least a portion of the gas storage structure is disposed within the tab space.

[0043] In some embodiments, the electrode space includes: a folded electrode region accommodating the electrode and a void region located around the folded electrode region, with at least a portion of the gas storage structure disposed in the void region.

[0044] In some embodiments, the gas storage structure located between the third wall and the electrode assembly is disposed adjacent to the second wall, and the maximum distance between the gas storage structure and the second wall is less than or equal to 5 mm.

[0045] In a second aspect of this application, an electrical device is proposed, including the secondary battery described in the first aspect of this application.

[0046] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0047] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0048] Figure 1 is a schematic diagram of an electrical device according to an embodiment of this application;

[0049] Figure 2 is a schematic diagram of a battery device according to an embodiment of this application;

[0050] Figure 3 is a schematic diagram of a battery cell according to an embodiment of this application;

[0051] Figure 4 is a schematic diagram of the disassembly of a battery cell according to an embodiment of this application;

[0052] Figure 5 is a schematic diagram of the end cap according to the first embodiment of this application;

[0053] Figure 6 is a schematic diagram of a battery cell according to the first embodiment of this application;

[0054] Figure 7 is a cross-sectional view of a single battery cell according to the first embodiment of this application from one angle;

[0055] Figure 8 is a cross-sectional view of a battery cell according to the first embodiment of this application from another angle;

[0056] Figure 9 is a cross-sectional view of a single battery cell according to the first embodiment of this application from another angle;

[0057] Figure 10 is a schematic diagram of a battery cell according to the second embodiment of this application;

[0058] Figure 11 is a cross-sectional view of a single battery cell according to a second embodiment of this application from one angle;

[0059] Figure 12 is a schematic diagram of a battery cell according to the third embodiment of this application;

[0060] Figure 13 is a cross-sectional view of a battery cell according to a third embodiment of this application from one angle;

[0061] Figure 14 is a schematic diagram of a battery cell according to the fourth embodiment of this application;

[0062] Figure 15 is a cross-sectional view of a battery cell according to the fourth embodiment of this application from one angle;

[0063] Figure 16 is a schematic diagram of an end cap according to a fifth embodiment of this application;

[0064] Figure 17 is a cross-sectional schematic diagram of the end cap according to the fifth embodiment of this application;

[0065] Figure 18 is a schematic diagram of the end cap according to the sixth embodiment of this application;

[0066] Figure 19 is a cross-sectional schematic diagram of the end cap according to the sixth embodiment of this application;

[0067] Figure 20 is a schematic diagram of a battery cell according to the seventh embodiment of this application;

[0068] Figure 21 is a schematic diagram of the end cap according to the eighth embodiment of this application;

[0069] Figure 22 is a cross-sectional schematic diagram of the end cap according to the eighth embodiment of this application. Detailed Implementation

[0070] The embodiments of the technical solution of this application are described in detail below. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.

[0071] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0072] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0073] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0074] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0075] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0076] Currently, judging from market trends, the application of rechargeable batteries is becoming increasingly widespread. Rechargeable batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace, among other fields.

[0077] Existing secondary battery products are triggered by a variety of factors during thermal runaway, and the proportion of gas produced during thermal runaway is large, generally 30%-60% H2. During the thermal runaway process, H2 also acts as a combustion gas, which can lead to more serious runaway consequences or open flames that may further induce other runaway events.

[0078] Existing methods for reducing thermal runaway in secondary batteries include measures that prevent it from the source, such as the selection of electrolyte solvents, choosing non-flammable solvents, and adding flame retardants to the battery. However, these methods require additional consideration of system changes and design to reduce failure, which is usually difficult to balance the electrical performance of secondary batteries, and flame retardants are generally expensive.

[0079] In this embodiment, since thermal runaway of the secondary battery generates a large amount of gas, analysis of the gas composition during thermal runaway reveals that the proportion of H2 is generally high at the moment of thermal runaway. Therefore, if the generated hydrogen gas can be absorbed before thermal runaway, the probability of thermal runaway can be greatly reduced. Thus, this embodiment incorporates a hydrogen storage alloy in the secondary battery, with a hydrogen absorption pressure of 0.3 MPa-0.5 MPa. Since the internal pressure of the secondary battery during normal operation is generally below 0.3 MPa, and the valve opening pressure during thermal runaway is generally between 0.5 MPa and 0.7 MPa, when thermal runaway occurs... During control, the internal pressure increases sharply. The hydrogen absorption pressure range of the hydrogen storage alloy is controlled between 0.3MPa and 0.5MPa. Furthermore, the hydrogen storage alloy is in powder form and packaged in a sealed bag, providing a large contact area with the gas. The alloy can absorb H2 generated by overcharging of the secondary battery and the rapidly generated H2 during runaway, thus mitigating the runaway problem caused by H2 as a flammable and explosive combustion-supporting gas. This effectively alleviates and delays the thermal runaway of the secondary battery, reducing its occurrence. In other words, the hydrogen storage alloy does not absorb hydrogen during normal use of the secondary battery, but absorbs flammable and explosive hydrogen components before the valve is opened, thereby improving the battery's tolerance temperature limit or mitigating thermal runaway. In addition, the hydrogen storage alloy has good compatibility with various secondary battery systems, eliminating the need to consider changes to the battery system, and its cost is also relatively low.

[0080] The secondary battery disclosed in this application can be used in electrical devices that use batteries as a power source or in various energy storage systems that use batteries as energy storage elements. Electrical devices may include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

[0081] The first aspect of this application discloses a secondary battery, which includes a battery body and a casing for housing the battery body. The battery body includes a positive electrode, an electrolyte, and a negative electrode. A plastic sealing bag is provided between the battery body and the casing, and the plastic sealing bag contains hydrogen storage alloy powder. The hydrogen absorption pressure of the hydrogen storage alloy is 0.3 MPa-0.5 MPa.

[0082] As an example, the hydrogen absorption pressure of a hydrogen storage alloy can be 0.3MPa-0.49MPa, 0.35MPa-0.45MPa, 0.38MPa-0.4MPa, etc. It can be understood that the hydrogen absorption pressure refers to the pressure at which the hydrogen storage alloy can absorb hydrogen gas, which is the effective absorption pressure range of hydrogen gas. That is to say, within the range of 0.3MPa-0.5MPa, the hydrogen storage alloy can absorb hydrogen gas.

[0083] It is understood that the "hydrogen absorption pressure of the hydrogen storage alloy" can be determined using methods known in the art, such as the following methods:

[0084] The following measurements were taken using the H2PCT-1153 3-channel fully automated hydrogen storage material performance testing system (Yangzhou Yinghui Zhiyue):

[0085] Pressure sensors: 2 full-range absolute pressure sensors (0-10MPa) and 1 sensor (0-15MPa), with an accuracy of 0.04%FS; Temperature sensors: RT-100℃, RT-300℃, RT-500℃; The furnace can be programmed to heat up; The temperature sensors are placed outside the sample chamber; The sample chamber volume is (H15mm×12mm); The sample chamber and test pipeline are connected via quick connectors.

[0086] The PCT curves (pressure-concentration isotherms) of the hydrogen storage materials were tested to determine the hydrogen absorption and desorption kinetics.

[0087] The gas cylinders consist of three 1000ml cylinders and three 150ml cylinders. The entire pipeline can withstand a pressure of 1×10⁻⁶. -6 The hydrogen pressure is -15 MPa. The vacuum pump used is an Edwards vacuum pump (equipped with a hose, and the exhaust gas is discharged outdoors).

[0088] The hydrogen absorption pressure of the hydrogen storage alloy was determined from the PCT curve.

[0089] The secondary battery in this application embodiment includes a hydrogen storage alloy with a hydrogen absorption pressure of 0.3MPa-0.5MPa. Since the internal pressure of the secondary battery before assembly or during normal operation is generally lower than 0.3MPa, the secondary battery can basically not absorb hydrogen gas before assembly, during the unsealed stage, and during normal operation, which does not affect the saturation of the hydrogen storage alloy and thus does not affect its absorption of flammable hydrogen gas in the secondary battery. Since the internal pressure of the secondary battery is 0.3MPa-0.5MPa at the moment of thermal runaway, the hydrogen storage alloy can absorb the H2 generated by overcharging of the secondary battery and the H2 rapidly generated during runaway. Moreover, the hydrogen storage alloy is placed in the plastic seal bag between the battery body and the shell in powder form, which has a large contact area with the generated H2 and can achieve rapid absorption of H2 before the battery spray valve. This improves the failure problem of H2 as a flammable and explosive combustion-supporting gas during thermal runaway, effectively alleviates and delays the thermal runaway of the secondary battery, and reduces the occurrence of thermal runaway of the secondary battery.

[0090] The hydrogen storage alloy is disposed between the battery body and the outer casing. This reduces the probability of the hydrogen storage alloy reacting with the electrolyte. The hydrogen storage alloy does not affect the operation of the battery body and does not require additional space. The hydrogen storage alloy can rapidly absorb hydrogen gas when it is generated, reducing the internal pressure of the secondary battery, lowering the risk of thermal runaway, and extending the battery's lifespan.

[0091] It is understandable that hydrogen storage alloys are alloys that can react with hydrogen and absorb it. The reaction process with hydrogen is as follows: first, hydrogen is catalyzed and decomposed into hydrogen atoms on its surface, and then the hydrogen atoms enter the interior of the hydrogen storage alloy lattice to generate metal hydrides, thus achieving the purpose of hydrogen storage.

[0092] It is understood that the material of the hydrogen storage alloy in the embodiments of this application can be determined using an X-ray diffractometer.

[0093] It is understood that the hydrogen storage alloy of this application embodiment can be placed in any location of the secondary battery. This application does not impose any restrictions. The specific location will be described in detail below.

[0094] In some embodiments of this application, the volume average particle size Dv50 of the hydrogen storage alloy is 2μm-25μm, for example, it can be 2μm-24μm, 5μm-20μm, 10μm-15μm, 12μm-13μm, etc. Controlling the volume average particle size Dv50 of the hydrogen storage alloy within this range results in a large specific surface area. This ensures a large contact area between the hydrogen storage alloy and the hydrogen gas during the instantaneous generation of a large amount of hydrogen gas in the secondary battery's thermal runaway. This allows for rapid contact and reaction with the hydrogen gas, absorbing the hydrogen gas generated by the secondary battery, thereby mitigating the failure of H2 as a flammable and explosive combustion-supporting gas during thermal runaway. This can effectively alleviate and delay the thermal runaway of the secondary battery, reducing its occurrence. Furthermore, it can also reduce the risk of combustion and explosion caused by excessively small hydrogen storage alloy particle size. In other embodiments of this application, the volume average particle size Dv50 of the hydrogen storage alloy is 2μm-10μm.

[0095] It is understood that the volume average particle size Dv50 refers to the particle size corresponding to a cumulative volume distribution percentage of 50%. The volume average particle size Dv50 of hydrogen storage alloys can be determined using methods known in the art, for example, by the following methods:

[0096] Referring to the standard GB / T 19077-2016, a laser diffraction scattering particle size analyzer (Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK) was used.

[0097] In some embodiments of this application, the BET specific surface area of ​​the hydrogen storage alloy is 1 m². 2 / g-10m 2 / g, for example, could be 1m 2 / g-9.9m 2 / g, 1m 2 / g-9m 2 / g, 2m 2 / g-8m 2 / g, 3m 2 / g-7m 2 / g, 4m 2 / g-6m 2 The BET specific surface area of ​​the hydrogen storage alloy is controlled within the above range. A large specific surface area ensures a large contact area between the hydrogen storage alloy and hydrogen gas during the instantaneous generation of a large amount of hydrogen gas in the secondary battery's thermal runaway. This allows for rapid contact and reaction with the hydrogen, absorbing the hydrogen gas generated by the secondary battery. This mitigates the failure of H2 as a flammable and explosive combustion-supporting gas during thermal runaway, effectively alleviating and delaying the occurrence of secondary battery thermal runaway. Furthermore, it reduces the risk of combustion and explosion caused by an excessively large specific surface area of ​​the hydrogen storage alloy. In some other embodiments of this application, the BET specific surface area of ​​the hydrogen storage alloy is 5m². 2 / g-10m 2 / g.

[0098] In this application, BET specific surface area has a well-known meaning in the art and can be determined using instruments and methods known in the art. For example, it can be tested using the nitrogen adsorption specific surface area analysis method according to GB / T 19587-2017, and calculated using the BET (Brunauer Emmett Teller) method. The testing instrument can be the Tri-Star 3020 specific surface area and pore size analyzer from Micromeritics, USA.

[0099] In some embodiments of this application, a plastic sealing bag is provided between the battery body and the outer casing. The plastic sealing bag contains powdered hydrogen storage alloy. Placing the hydrogen storage alloy in powder form within the plastic sealing bag and fixing the bag between the battery cell and the outer casing provides a large contact area between the powdered hydrogen storage alloy and hydrogen gas, enabling rapid absorption of hydrogen gas when it is generated. This mitigates the failure of H2 as a flammable and explosive combustion-supporting gas during thermal runaway, effectively alleviating and delaying thermal runaway of the secondary battery and reducing its occurrence. Furthermore, using a plastic sealing bag to hold the hydrogen storage alloy powder reduces the probability of the hydrogen storage alloy scattering and affecting battery stability.

[0100] In other embodiments of this application, a sealed plastic bag containing hydrogen storage alloy powder is placed at the top of the battery casing, such as on the top cover. Since hydrogen has a low density, most of the generated hydrogen gas concentrates at the top of the secondary battery. Placing the hydrogen storage alloy at the top, such as on the top cover, further improves the efficiency of the reaction between the hydrogen storage alloy and hydrogen, enhancing the hydrogen absorption effect. This can further mitigate the failure of H2 as a flammable and explosive combustion-supporting gas during thermal runaway, effectively alleviating and delaying thermal runaway of the secondary battery, and reducing its occurrence.

[0101] In some embodiments of this application, the air permeability of the plastic-sealed bag is 100s / 100mL-1000s / 100mL. For example, the air permeability of the plastic seal bag can be 100s / 100mL-900s / 100mL, 200s / 100mL-800s / 100mL, 300s / 100mL-700s / 100mL, 400s / 100mL-600s / 100mL, etc. It can be understood that in the embodiments of this application, air permeability refers to the time required for 100mL of gas to pass through the plastic seal bag from the outside to the inside. Taking an air permeability of 1000s / 100mL as an example, it means that 100mL of gas takes 1000s to pass through the plastic seal bag. Specifically, by controlling the air permeability of the plastic seal bag within the above range, the hydrogen gas generated during the thermal runaway of the secondary battery can quickly pass through the plastic seal bag and enter its interior to react with the hydrogen storage alloy, thereby improving the failure problem of H2 as a flammable and explosive combustion-supporting gas during thermal runaway. This can effectively alleviate and delay the thermal runaway of the secondary battery and reduce the occurrence of thermal runaway of the secondary battery. In some other embodiments of this application, the air permeability of the plastic-sealed bag is 100s / 100mL-500s / 100mL.

[0102] It is understandable that the "air permeability of a plastic sealable bag" can be measured using the following methods:

[0103] Air permeability analysis was performed using the MP010 Gurley method, with the test method referring to GB / T 458-2008.

[0104] In some embodiments of this application, the material of the plastic seal bag includes at least one of polyethylene, polypropylene, EPDM rubber, or nitrile rubber. The aforementioned plastic seal bag has high air permeability, allowing hydrogen gas generated instantaneously during thermal runaway of the secondary battery to rapidly enter the bag and fully react with the hydrogen storage alloy powder. This mitigates the failure of H2 as a flammable and explosive combustion-supporting gas during thermal runaway, effectively alleviating and delaying thermal runaway of the secondary battery and reducing its occurrence.

[0105] In some embodiments of this application, the amount of hydrogen storage alloy added to the secondary battery is 0.005 g / Ah-2.4 g / Ah. For example, it can be 0.005 g / Ah-2.3 g / Ah, 0.01 g / Ah-2.2 g / Ah, 0.5 g / Ah-2.1 g / Ah, 1 g / Ah-2 g / Ah, 1.5 g / Ah-1.8 g / Ah, etc. Controlling the amount of hydrogen storage alloy added to the secondary battery within the above range is sufficient to absorb the rapidly generated H2 during the thermal runaway of the secondary battery, thereby improving the failure problem of H2 as a flammable and explosive combustion-supporting gas during thermal runaway, which can effectively alleviate and delay the thermal runaway of the secondary battery; it can also reduce the impact of excessive hydrogen storage alloy addition on the battery's energy density. In other embodiments of this application, the amount of hydrogen storage alloy added is 0.04 g / Ah-0.8 g / Ah.

[0106] It is understandable that when the amount of hydrogen storage alloy added is 0.04g / Ah-0.8g / Ah, the thermal runaway performance and energy density of the battery can be better balanced.

[0107] It is understood that the amount of hydrogen storage alloy added, i.e., the mass of hydrogen storage alloy added per unit Ah of secondary battery, can be determined using methods known in the art, such as the following methods:

[0108] The secondary battery is disassembled, the hydrogen storage alloy is removed, weighed, and then divided by the capacity of the secondary battery to obtain the amount of hydrogen storage alloy to be added.

[0109] Test method for secondary battery capacity: Select the secondary battery to be tested, and use a secondary battery charge / discharge machine and a high / low temperature chamber to test the full charge capacity and discharge capacity of the secondary battery at a standard rate at 25℃. The discharge capacity is the capacity value of the secondary battery. The charge / discharge rate is 0.33C (C represents the rated capacity of the secondary battery. The charge / discharge current is the rate multiplied by the rated capacity of the secondary battery, which is based on the capacity of the secondary battery as defined in the GBT certification document).

[0110] In some embodiments of this application, the negative electrode sheet includes a negative current collector and an interface modification layer disposed on at least one side of the negative current collector. The interface modification layer includes a binder and a conductive agent. That is, there is no active metal in the negative electrode sheet, and the prepared battery is called a negative electrode-free battery. The setting of the interface modification layer can make the active metal (alkali metal) uniformly deposited on the surface of the interface modification layer, thereby improving the cycle performance of the battery.

[0111] Furthermore, the secondary battery containing the aforementioned negative electrode is an alkali metal battery. Specifically, an alkali metal battery refers to a battery that uses an active metal as the negative electrode, such as lithium metal or sodium metal. In these types of secondary batteries, the active metal ions on the negative electrode, such as lithium and sodium, are relatively active and will undergo side reactions with water, solvents in the electrolyte, and residual alkali in the positive electrode active material, resulting in a large amount of gas production, with H2 accounting for >90% of the gas. For the aforementioned batteries where the main gas produced is hydrogen, by incorporating a hydrogen storage alloy into the battery, the hydrogen produced in the battery can be absorbed, reducing the excessive internal pressure of the secondary battery, with better results. The cycle life of the aforementioned secondary batteries is significantly improved.

[0112] It's understandable that a "negative electrode-free battery" refers to a battery where no negative electrode active material is added during the battery manufacturing stage. However, a negative electrode current collector is still present. A negative electrode-free battery is simply a special type of alkali metal battery (such as lithium metal batteries and sodium metal batteries), not a battery that truly lacks a negative electrode. In actual operation, the negative electrode still contains an active metal (such as lithium metal or sodium metal). The negative electrode in a negative electrode-free battery includes a bare negative electrode current collector (such as copper). Taking a lithium battery as an example, during battery charging, active metal ions such as Li... + The lithium metal is extracted from the positive electrode and deposited on the negative electrode current collector to form a lithium negative electrode. During subsequent battery discharge, the deposited lithium metal dissolves and is reinserted into the positive electrode.

[0113] In some embodiments of this application, the thickness of the interface modification layer is 0.5 μm-5 μm. For example, it can be 0.5 μm-4.9 μm, 1 μm-4 μm, 2 μm-3 μm, etc. Controlling the thickness of the interface modification layer within the above range can further enable the active metal (alkali metal) to be uniformly deposited on the surface of the interface modification layer, thereby improving the cycle performance of the battery.

[0114] It is understood that the "thickness of the interface modification layer" is a well-known definition in the art and can be measured using methods known in the art, such as the following methods:

[0115] General steps and relevant parameters for cross-sectional polishing of interface repair layer thickness using the Zeiss Sigma 300 ion polishing system:

[0116] Ion polishing steps:

[0117] Secure the negative electrode sample to the sample stage using conductive adhesive, ensuring the sample is flat and has good conductivity. Turn on the Zeiss Sigma 300 ion polishing system, preheat the equipment, and set the initial operating parameters, including ion beam energy, tilt angle, and polishing time. Perform an initial cut using a lower ion beam energy to quickly remove impurities from the sample surface. Adjust the sample stage tilt angle and use an ion beam to bevel the sample cross-section to create a suitable observation section. Gradually reduce the ion beam energy and meticulously polish the sample surface to minimize surface damage. Perform final polishing at lower energies until the sample surface achieves the required smoothness and clarity. After polishing, clean the sample surface with an appropriate solvent to remove residual polishing solution. Dry the sample in preparation for SEM observation. Remove the polished sample from the ion polishing system and transfer it to the SEM sample chamber. Observe the sample under SEM. Use the built-in scale of the device to measure the thickness of the interface modification layer and analyze the thickness distribution of the interface modification layer cross-section (generally, test 2-3 samples at different locations, measuring the thickness of each sample at 50µm intervals, and take the average thickness of the tested samples as the average thickness output (combined with EDS analysis to distinguish the current collector part, the thickness of the remaining part is marked as the thickness of the interface modification layer). Due to consistency and testing errors, the average thickness output is retained with 0 / 5 decimal places.

[0118] Ion source: Argon (Ar) is usually used as the ion source.

[0119] Ion beam energy: 1-2 keV may be used for initial cutting, and reduced to 0.5-1 keV during the polishing stage.

[0120] Tilt angle: Adjust as needed, usually between 5-15 degrees.

[0121] Polishing time: Adjusted according to the sample material and polishing effect, which may range from a few minutes to tens of minutes.

[0122] Working distance: The distance between the ion beam and the sample surface, typically 3-5 mm.

[0123] In some embodiments of this application, the electrolyte includes a solvent, which includes at least one of ether solvents or ester solvents. It is understood that ether solvents refer to organic solvents containing ether groups, and ester solvents refer to organic solvents containing ester groups. When a secondary battery containing the above solvents experiences thermal runaway, H2 is rapidly generated. The hydrogen storage alloy of this application embodiment can quickly absorb the large amount of hydrogen generated, thereby improving the failure problem of H2 as a flammable and explosive combustion-supporting gas during thermal runaway. This can effectively alleviate and delay the thermal runaway of the secondary battery, allowing the hydrogen storage alloy to absorb the hydrogen, reducing the internal pressure of the secondary battery, and extending the battery's lifespan.

[0124] In some embodiments of this application, the solvent includes ether solvents, which include at least one of 1,2-dimethoxypropane, dimethoxymethane, ethylene glycol dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, pentaethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, or 1,3-dioxopentane. The aforementioned ether solvents are compatible with various secondary batteries, especially alkali metal batteries. Furthermore, secondary batteries containing these solvents rapidly generate H2 during thermal runaway. The hydrogen storage alloy of this application embodiment can quickly absorb the large amount of hydrogen generated, thereby improving the failure problem of H2 as a flammable and explosive combustion-supporting gas during thermal runaway. It can effectively alleviate and delay the thermal runaway of the secondary battery, allowing the hydrogen storage alloy to absorb the hydrogen, reduce the internal pressure of the secondary battery, and extend the life of the secondary battery.

[0125] In some embodiments of this application, the hydrogen storage alloy includes magnesium-based alloys, titanium-based alloys, or LaNi alloys. y M z At least one of the following, wherein M includes at least one of Zr, Mn, Mg, Zn, Al, Ti, Fe, Cu, Co, Bi or Ca, 2≤y≤9, 0≤z≤5, and 7≤y+z≤9.

[0126] As an example, y can be 2-8.9, 3-7, 4-6, etc.

[0127] z can be 0.1-4.9, 1-4, 2-3, etc.

[0128] y+z can be 7-8.9, 7.5-8.5, 8-8.5, etc. Controlling the content of doping elements and nickel within the above range can increase the minimum hydrogen absorption pressure of the hydrogen storage alloy, making its hydrogen absorption pressure 0.3MPa-0.5MPa.

[0129] In other embodiments, M includes at least one of Ti, Mn, Mg, Zr, Bi, or Fe.

[0130] The hydrogen storage alloy described above has a hydrogen absorption pressure of 0.3MPa-0.5MPa, which ensures that it does not absorb hydrogen gas before secondary battery assembly, during the unsealed stage, or during normal operation. This does not affect the saturation of the hydrogen storage alloy or its ability to absorb flammable hydrogen gas within the secondary battery. Furthermore, it has a hydrogen absorption platform, requiring a relatively high internal battery pressure (0.3MPa-0.5MPa). The internal pressure (0.3MPa-0.5MPa) before the battery spray valve enables rapid H2 absorption. This allows the flammable hydrogen gas inside the secondary battery to be absorbed before thermal runaway, reducing the risk of thermal runaway.

[0131] In some embodiments of this application, the magnesium alloy and / or the titanium alloy contain iron. The doping of iron can increase the hydrogen absorption pressure of the hydrogen storage alloy to 0.3MPa-0.5MPa. The internal pressure (0.3MPa-0.5MPa) before the battery valve can achieve rapid absorption of H2, thereby reducing the occurrence of thermal runaway of the secondary battery.

[0132] In some embodiments of this application, the titanium alloy includes TiNi. 0.5 Fe 0.5 or Ti2Ni 0.5 Fe 0.5 At least one of the following, titanium alloys refer to alloys containing titanium. The aforementioned titanium alloys contain iron as a dopant, which can increase their hydrogen absorption pressure to 0.3MPa-0.5MPa. This allows them to absorb H2 generated by overcharging of the secondary battery and H2 rapidly generated during battery failure. The internal pressure (0.3MPa-0.5MPa) before the battery valve enables rapid absorption of H2, thereby improving the failure problem of H2 as a flammable and explosive combustion-supporting gas during thermal runaway. This can effectively alleviate and delay the thermal runaway of the secondary battery and reduce the occurrence of thermal runaway.

[0133] In some embodiments of this application, the magnesium alloy includes Mg2Ni. 0.5 Fe 0.5 Mg2Al 0.5 Fe 0.5 Mg2Cr 0.5 Fe 0.5 or Mg2Te 0.5 Fe 0.5 At least one of the following. Magnesium alloys refer to alloys containing magnesium. The aforementioned magnesium alloys contain iron as a dopant, which can increase their hydrogen absorption pressure to 0.3MPa-0.5MPa. This allows them to absorb H2 generated by overcharging of the secondary battery and the rapidly generated H2 during battery failure. The internal pressure (0.3MPa-0.5MPa) before the battery valve enables rapid absorption of H2, thereby mitigating the problem of H2 acting as a flammable and explosive combustion-supporting gas during thermal runaway. This can effectively alleviate and delay the thermal runaway of the secondary battery, reducing its occurrence.

[0134] In some embodiments of this application, the hydrogen storage alloy comprises La 0.5 Ni 4.5 Y 0.5 LaNi 3.5 Mn 0.2 YBi 0.3 LaNi 3.5 Mn 0.6 Y 0.4 Bi0.5 LaNi 3.5 Mn 0.2 Y 0.4 Bi 0.9 LaTi 3.5 Fe 0.4 Zr 0.5 Bi 0.6 LaTi 3.5 Fe 0.4 Zr 0.5 Mg 0.6 LaNi 4.26 Al 0.08 Mg 0.16 Or La 0.7 Mg 0.3 Ni 2.8 Co 0.3 At least one of the following. The hydrogen absorption pressure of the above-mentioned hydrogen storage alloy is 0.3MPa-0.5MPa, which can absorb H2 generated by overcharging of the secondary battery and H2 generated rapidly during failure. The internal pressure (0.3MPa-0.5MPa) before the battery spray valve can achieve rapid absorption of H2, thereby improving the failure problem of H2 as a flammable and explosive combustion-supporting gas during thermal runaway. It can effectively alleviate and delay the thermal runaway of the secondary battery and reduce the occurrence of thermal runaway of the secondary battery.

[0135] This application does not limit the preparation method of the above-mentioned hydrogen storage alloy. As an example, the preparation method of the above-mentioned hydrogen storage alloy may be: mixing the metal elements corresponding to each element of the hydrogen storage alloy in the molar ratio shown in the chemical formula, heating and melting under air-isolated conditions, and cooling to obtain the hydrogen storage alloy.

[0136] Typically, a battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. During charging and discharging, active metal ions repeatedly insert and extract between the positive and negative electrodes. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing ions to pass through.

[0137] In some embodiments of this application, the positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one side of the positive current collector, wherein the positive active material layer includes the aforementioned irreversible positive electrode additive.

[0138] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0139] In some embodiments of this application, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0140] In some embodiments of this application, when the battery is a lithium secondary battery, the positive electrode active material may be a positive electrode active material known in the art for lithium-ion batteries.

[0141] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure may include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. The modified compounds of the above materials may be for doping modification and / or surface coating modification of the materials.

[0142] During the charging and discharging process of a battery, Li undergoes insertion / extraction and consumption, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this application, the molar Li content refers to the initial state of the material, i.e., the state before material addition. After charge-discharge cycles, the molar Li content changes when the positive electrode active material is applied to the battery system.

[0143] In the examples of positive electrode active materials in this application, the molar content of O is only a theoretical value. Oxygen release from the crystal lattice will cause changes in the molar content of oxygen, and the actual molar content of O will fluctuate.

[0144] In some embodiments of this application, when the battery is a sodium secondary battery, the positive electrode active material may be a positive electrode active material known in the art for sodium-ion batteries.

[0145] As an example, the positive electrode active material may include at least one of the following materials: sodium transition metal oxides, polyanionic compounds, and Prussian blue sodium compounds, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. The modified compounds of the above materials may be for doping modification and / or surface coating modification of the materials.

[0146] In some embodiments of this application, the transition metal in the sodium transition metal oxide can be at least one selected from Ti, V, Mn, Co, Ni, Fe, Zn, V, Zr, Ce, Cr, and Cu. The chemical formula of the sodium transition metal oxide can satisfy Na y MO2, wherein M includes at least one of Ti, V, Mn, Co, Ni, Fe, Zn, V, Zr, Ce, Cr, and Cu, and 0 < y ≤ 1.

[0147] In some embodiments of this application, the polyanionic compound may be a compound containing sodium ions, transition metal ions, or a tetrahedral (YO4) structure. n- A class of compounds with anionic units. The transition metal may include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce; Y may include at least one of P, S, and Si; n represents (YO4). n-The price state.

[0148] In some embodiments of this application, the polyanionic compound may also be a sodium ion, transition metal ion, or tetrahedral (YO4) compound. n- A class of compounds containing anionic units and halide anions. Transition metals may include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce; Y may include at least one of P, S, and Si, where n represents (YO4). n- The valence state of halogens can include at least one of F, Cl, and Br.

[0149] In some embodiments of this application, the polyanionic compound may also be a tetrahedral compound containing sodium ions (YO4). n- Anionic unit, polyhedral unit (ZO) y ) m+ And a class of compounds with optional halide anions. M may include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce, Y may include at least one of P, S and Si, and n represents (YO4). n- The valence state, Z represents transition metal, m represents (ZO) y ) m+ The valence state of halogens can include at least one of F, Cl, and Br.

[0150] As an example, polyanionic compounds can satisfy the chemical formulas NaFePO4, Na3V2(PO4)3 (sodium vanadium phosphate, abbreviated as NVP), Na4Fe3(PO4)2(P2O7), NaM'PO4F (M' includes at least one of V, Fe, Mn and Ni), and Na3(VO y )2(PO4)2F 3-2y At least one of (0≤y≤1).

[0151] In some embodiments of this application, Prussian blue compounds may be compounds containing sodium ions, transition metal ions, and cyanide ions (CN). - A class of compounds. Transition metals may include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce.

[0152] As an example, Prussian blue compounds can satisfy the chemical formula Na a Me b Me' c (CN)6, wherein Me and Me' each independently include at least one of Ni, Cu, Fe, Mn, Co, and Zn, 0 < a ≤ 2, 0 < b < 1, and 0 < c < 1.

[0153] During the charging and discharging process of a battery, sodium (Na) undergoes insertion / extraction and consumption, resulting in varying molar Na content at different discharge states. In the examples of positive electrode active materials in this application, the molar Na content refers to the initial state of the material, i.e., the state before material addition. After charge-discharge cycles, the molar Na content changes when the positive electrode active material is applied to the battery system.

[0154] In the examples of positive electrode active materials for sodium-ion batteries in this application, the molar content of O is only a theoretical value. Oxygen release from the crystal lattice will cause changes in the molar content of oxygen, and the actual molar content of O will fluctuate.

[0155] In some embodiments of this application, the positive electrode active material layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0156] In some embodiments of this application, the positive electrode active material layer may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0157] In some embodiments of this application, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder, positive irreversible additive and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0158] In some embodiments of this application, the negative electrode sheet includes a negative current collector and a negative active material layer disposed on at least one side of the negative current collector.

[0159] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0160] In some embodiments of this application, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0161] In some embodiments of this application, the negative electrode active material may be any negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and titanates. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. When the battery is a lithium-ion battery, the titanate includes lithium titanate; when the battery is a sodium-ion battery, the titanate includes sodium titanate. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0162] In some embodiments of this application, the negative electrode active material layer may optionally include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0163] In some embodiments of this application, the negative electrode active material layer may optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0164] In some embodiments of this application, the negative electrode active material layer may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0165] In some embodiments of this application, the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0166] In some embodiments of this application, the battery includes a lithium metal negative electrode or a sodium metal negative electrode. In this case, the negative electrode includes a negative current collector and an active material layer disposed on at least a portion of the surface of the negative current collector. The active material layer includes at least one of elemental lithium metal or a lithium metal alloy. Alternatively, the active material includes at least one of sodium metal or a sodium metal alloy.

[0167] In some embodiments of this application, the lithium metal alloy has the chemical formula LiR, where R includes at least one of tin, zinc, aluminum, magnesium, silver, gold, gallium, indium, platinum, boron, carbon, or silicon.

[0168] In some other embodiments of this application, the sodium metal alloy has the chemical formula NaR1, where R1 includes at least one of tin, zinc, aluminum, magnesium, silver, gold, gallium, indium, platinum, boron, carbon, or silicon.

[0169] In some embodiments of this application, when a lithium metal negative electrode sheet is used, the preparation method is as follows: lithium foil or lithium metal alloy is coated onto the current collector by single-sided rolling, and then cut into negative electrode sheets.

[0170] In some other embodiments of this application, when a sodium metal negative electrode sheet is used, the preparation method is as follows: sodium foil or sodium metal alloy is coated onto the current collector by single-sided rolling, and then cut into negative electrode sheets.

[0171] In some embodiments of this application, the battery may also be a negative electrode-free battery, wherein no negative electrode active material is added to the negative electrode active material layer or no negative electrode active material layer is provided when preparing the negative electrode sheet.

[0172] This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or completely solid.

[0173] In some embodiments of this application, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0174] In some embodiments of this application, when the battery is a lithium-ion battery, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, or lithium tetrafluorooxalate phosphate.

[0175] In some embodiments of this application, when the battery is a sodium-ion battery, the electrolyte salt may include at least one of sodium hexafluorophosphate, sodium difluorooxalate borate, sodium tetrafluoroborate, sodium dioxalate borate, sodium perchlorate, sodium hexafluoroarsenate, sodium bis(fluorosulfonyl)imide, sodium trifluoromethanesulfonate, or sodium bis(trifluoromethanesulfonyl)imide.

[0176] In some embodiments of this application, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, ethylene glycol dimethyl ether, methyl ethyl sulfone, or diethyl sulfone.

[0177] In some embodiments of this application, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0178] This application does not impose any particular restrictions on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0179] In some embodiments of this application, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, or polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0180] The secondary batteries of this application include single-cell battery forms, battery module forms, and battery pack forms. The following description, with appropriate reference to the accompanying drawings, will illustrate the single-cell battery, battery module, and battery pack of this application.

[0181] In some embodiments of this application, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly by a winding process or a stacking process.

[0182] In some embodiments of this application, the battery cell may include an outer packaging. This outer packaging can be used to encapsulate the aforementioned electrode assembly and electrolyte.

[0183] In some embodiments of this application, the outer packaging of the battery cell can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the secondary battery can also be a soft pack, such as a pouch-type soft pack. The material of the soft pack can be plastic, and examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0184] It is understood that the secondary battery mentioned in this application refers to a single battery cell. A secondary battery is a single battery cell that can be recharged after discharge to activate the active materials and continue to be used.

[0185] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which may form a battery array, and the multiple battery cells may be connected in series, parallel, or in a mixed configuration via a busbar.

[0186] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells, such as forming a battery array.

[0187] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0188] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0189] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0190] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0191] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0192] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0193] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0194] The technical solutions described in the embodiments of this application are applicable to battery devices and electrical devices that use battery devices.

[0195] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0196] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0197] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle provided in some embodiments of this application. A battery device 200 is installed inside the vehicle, and the battery device 200 can be located at the bottom, front, or rear of the vehicle. The battery device 200 can be used to power the vehicle; for example, the battery device 200 can serve as the vehicle's operating power source.

[0198] The vehicle may also include a controller 500 and a motor 400. The controller 500 controls the battery device 200 to supply power to the motor 400, which serves as a load, for example, for the power needs of the vehicle during starting, navigation and driving.

[0199] In some embodiments of this application, the battery device 200 can not only serve as the operating power source for the vehicle, but also as the driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0200] Please refer to Figure 2, which is an exploded view of a battery device 200 provided in some embodiments of this application. The battery device 200 includes a housing 600 for accommodating individual battery cells 100.

[0201] The housing 600 is a component that houses the individual battery cells 100. The housing 600 provides placement space for multiple battery cells 100 and can adopt various structures. In some embodiments, the housing 600 may include a tray and a cover, which overlap to define a placement space for accommodating the battery cells 100. The tray and cover can be of various shapes, such as cuboids, cylinders, etc. The tray can be a hollow structure open on one side, and the cover can also be a hollow structure open on one side, with the open side of the cover overlapping the open side of the tray, thus forming a housing 600 with placement space. Alternatively, the tray can be a hollow structure open on one side, and the cover can be a plate-like structure, overlapping the open side of the tray, thus forming a housing 600 with placement space. As an example, the battery cell 100 can be a cylindrical battery cell 100, a prismatic battery cell 100, or a battery cell 100 of other shapes (such as a pouch battery cell 100), and this application does not impose any particular limitations.

[0202] In the battery device 200, there can be one or more battery cells 100. If there are multiple battery cells 100, they can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 100 are connected in both series and parallel. Alternatively, multiple battery cells 100 can be first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed manner to form a whole, which is then housed within the housing 600. Another option is that all battery cells 100 can be directly connected in series, parallel, or in a mixed manner, and then the whole consisting of all battery cells 100 is housed within the housing 600.

[0203] The battery cell 100 serves as the smallest energy unit of the battery device 200. The battery device 200 includes multiple battery cells 100. Each battery cell 100 includes a housing 10, an end cap 11, and an electrode assembly 20 disposed within the housing 10.

[0204] The battery cell 100 includes: a housing 10, an end cap 11, and an electrode assembly 20. The housing 10 is used to define an accommodating space with an installation opening. The housing 10 can be a pouch structure that wraps around the electrode assembly 20 for a pouch battery, or it can be constructed as a hard shell structure, with the electrode assembly 20 disposed therein.

[0205] For example, the housing 10 may include a base plate and a side plate. The side plate surrounds the periphery of the base plate and defines an accommodating space with a mounting opening. The electrode assembly 20 and other functional components may be disposed in the accommodating space. The end cap 11 covers the mounting opening of the housing 10 to isolate the internal environment of the battery cell 100 from the external environment. The shape of the end cap 11 is adapted to the shape of the housing 10. The end cap 11 may be supported by a material with a certain hardness and strength (such as aluminum alloy or carbon fiber plate). The end cap 11 can effectively protect the safety and reliability of the internal components of the housing 10 when squeezed or impacted.

[0206] In some embodiments, the end cap 11 may also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 100 reaches a threshold. The end cap 11 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating member may also be provided on the inner side of the end cap 11. The insulating member can be used to isolate the electrical connection components within the housing 10 from the end cap 11 to reduce the risk of short circuits. For example, the insulating member can be plastic, rubber, etc., and an insulating sheet can also be provided between the electrode assembly 20 and the housing 10 to achieve insulation protection.

[0207] The outer casing 10 is a component used to cooperate with the end cap 11 to form the internal environment of the battery cell 100, wherein the formed internal environment can accommodate the electrode assembly 20, electrolyte, and other components. The outer casing 10 and the end cap 11 can be independent components. A mounting opening can be provided on the outer casing 10, and the end cap 11 closes the opening at the mounting opening to form the internal environment of the battery cell 100. The outer casing 10 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the outer casing 10 can be determined according to the specific shape and size of the electrode assembly 20. The material of the outer casing 10 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this.

[0208] Electrode assembly 20 is the component in the battery cell 100 where electrochemical reactions occur. The casing 10 may contain one or more electrode assemblies 20. The electrode assembly 20 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly 20, while the portions of the positive and negative electrode sheets without active material each constitute a tab 21. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery device 200, the positive and negative active materials react with the electrolyte, and the tabs 21 connect to the electrode terminals 13 to form a current loop.

[0209] In related technologies, some battery systems (such as alkali metal batteries) produce a large amount of gas and produce gas rapidly during long-term cycling and storage. A considerable proportion of the gas is flammable and explosive hydrogen. The safety risk of the battery cell 100 is high. Not only is the gas emitted flammable, but the internal pressure is also high, which can easily lead to premature valve opening. The gas produced by the battery cell 100 needs to be discharged or treated in a timely manner.

[0210] It should be noted that common alkali metal batteries (including but not limited to lithium metal batteries, sodium metal batteries, potassium metal batteries, zinc metal batteries, and aluminum metal batteries) exhibit very significant differences in gas production patterns (including gas production amount, gas composition, and gas production rate) compared to secondary alkali ion batteries (such as lithium ion batteries, sodium ion batteries, and sodium-lithium ion batteries) during long-term charge and discharge processes.

[0211] Specifically, during the cycling and storage of battery cell 100, the amount of gas produced within battery cell 100 can accumulate rapidly in a short period of time, compressing the internal residual space of battery cell 100, and even causing the gas to be unable to be released, directly triggering the explosion-proof valve. At the same time, the gas produced by alkali metal batteries is often accompanied by reactive gases such as hydrogen and oxygen.

[0212] Based on the technical drawbacks of alkali metal batteries, such as large and rapid gas production, a high proportion of chemically active hydrogen, and the high risk of gas production and direct emission, the battery cell 100 of this application further incorporates a gas storage structure 30 within the casing 10 to rapidly absorb the produced gas within the casing 10. This maintains stable internal pressure within the battery cell 100, reducing the probability of premature valve opening and extending the service life of the battery cell 100. Furthermore, it improves venting and reduces the amount of hydrogen directly emitted, thereby enhancing safety.

[0213] The following description, with reference to Figures 1-22, describes a battery cell (secondary battery) 100, a battery device 200, and an electrical device 300 according to embodiments of this application.

[0214] As shown in Figures 3 and 4, this application provides a secondary battery 100, including: an electrode assembly 20, an electrolyte, and a gas storage structure 30. The electrode assembly 20 is housed within a housing 10 and includes a positive electrode and a negative electrode. A gap is formed between the electrode assembly 20 and the housing 10. The electrolyte includes an electrolyte solution, which is housed within the housing 10. A portion of the electrolyte solution is immersed in the electrode assembly 20, and a portion of the electrolyte solution is housed in a part of the gap. The gas storage structure 30 is housed within the housing 10 and is at least partially located in the other part of the gap. At least a portion of the gas storage structure 30 is a hydrogen storage alloy.

[0215] The electrode assembly 20, electrolyte, and gas storage structure 30 are all disposed inside the outer casing 10. The electrolyte is filled inside the outer casing 10, and the gas storage structure 30 is used to absorb the gas (including but not limited to hydrogen) generated inside the outer casing 10.

[0216] Specifically, the internal space of the housing 10 is slightly larger than the size of the electrode assembly 20, so that after the electrode assembly 20 is assembled into the housing 10, a gap is formed between the housing 10 and the electrode assembly 20. The electrolyte is injected into the housing 10 and is suitable for wetting the electrode assembly 20 and filling at least part of the gap. The other part of the gap can be used to set the gas storage structure 30, so that the gas storage structure 30 can be set inside the housing 10 and can be separated from the electrolyte.

[0217] It should be noted that the outer casing 10 can be disposed inside the housing 600 of the battery device 200, and the electrolyte can be located below the outer casing 10 under the action of gravity. The upper part of the gap of the outer casing 10 can be used to accommodate the gas storage structure 30, and at least part of the gas storage structure 30 is a hydrogen storage alloy so that the gas storage structure 30 can absorb the hydrogen generated during the charging and discharging of the battery cell 100.

[0218] It is understood that other portions of the gap may include: a gap portion defined between the upper sidewall of the housing 10 and the upper side of the electrode assembly 20, and a gap portion defined between other sidewalls of the housing 10 on the periphery of the upper sidewall and other sidewalls of the electrode assembly 20 on the periphery of the upper sidewall and adjacent to a portion of the upper sidewall of the housing 10, the two gap portions collectively defining other portions of the gap.

[0219] For example, the housing 10 defines an accommodating space, the electrode assembly 20 is disposed within the accommodating space, the electrolyte is filled within the accommodating space and is suitable for wetting the electrode assembly 20, the gas storage structure 30 is disposed within the accommodating space, and the battery cell 100 is configured as an alkali metal battery. During the charging and discharging process, the electrolyte and the electrode assembly 20 react to generate a large amount of hydrogen gas, and the gas storage structure 30 can absorb the hydrogen gas to reduce gas accumulation inside the housing 10, thereby maintaining the pressure stability inside the housing 10, reducing the probability of the housing 10 bulging or premature valve opening, extending the service life of the battery cell 100, and reducing or even avoiding the emission of hydrogen gas to the outside, thereby improving the safety of the space where the battery cell 100 is located, and thus improving the safety of the battery cell 100 in use.

[0220] It should be noted that alkali metal batteries produce a large amount of gas and produce gas rapidly, which causes the pressure inside the casing 10 to rise rapidly in a short period of time. In this application, at least part of the gas storage structure 30 is located between the electrolyte surface and the top wall, which can improve the absorption efficiency of the gas storage structure 30 so that the absorption efficiency of the gas storage structure 30 can match the gas production rate, realize the immediate production and absorption of hydrogen inside the casing 10, and thus keep the pressure inside the casing 10 stable.

[0221] According to the embodiments of this application, the battery cell 100 has a gas storage structure 30 provided inside the outer casing 10, and the gas storage structure 30 can be located in another part of the gap. The gas storage structure 30 absorbs the hydrogen generated inside the outer casing 10, thereby reducing the probability of valve opening, extending the service life of the battery cell 100, reducing the amount of hydrogen emitted, improving safety, and improving absorption efficiency. This allows the hydrogen absorption rate to match the hydrogen generation rate, so that the pressure inside the outer casing 10 can be kept stable, reducing the probability of a sharp increase in pressure inside the outer casing 10 and maintaining internal pressure stability.

[0222] According to some embodiments of this application, the housing 10 includes a first wall 10a and a second wall 10b, the first wall 10a and the second wall 10b are disposed opposite to each other, the first wall 10a supports the electrode assembly 20, and at least a portion of the gap is formed between the second wall 10b and the electrode assembly 20, and at least a portion of the gas storage structure 30 is disposed between the electrode assembly 20 and the second wall 10b.

[0223] Specifically, the first wall 10a and the second wall 10b can be arranged opposite each other in the height direction, with the first wall 10a located below and adapted to carry and support the electrode assembly 20, while the second wall 10b is arranged opposite to the first wall 10a, and at least part of the gap is formed between the second wall 10b and the electrode assembly 20, and a gas storage structure 30 can be arranged in the gap between the second wall 10b and the electrode assembly 20.

[0224] Thus, the first wall 10a supports the electrode assembly 20 and is opposite to the second wall 10b, so that the electrolyte surface is located between the second wall 10b and the first wall 10a. The gas storage structure 30 is further disposed adjacent to the second wall 10b and is at least partially located between the electrolyte surface and the second wall 10b. That is, the gas storage structure 30 can be completely located between the electrolyte surface and the second wall 10b, or partially located between the electrolyte surface and the second wall 10b. The gas storage structure 30 located between the electrolyte surface and the second wall 10b has a larger contact area with hydrogen, which can improve the absorption efficiency of hydrogen generated inside the outer casing 10.

[0225] It is understood that the outer shell 10 can be a prism, such as a quadrangular prism or a hexagonal prism. The second wall 10b and the first wall 10a are relative concepts, meaning they are two opposing walls. These two walls can be defined by two opposing surfaces on the outer shell 10. For example, if the outer shell of the battery cell 100 is a quadrangular prism, the battery cell 100 includes a large surface area (the surface with the largest surface area), a battery end face (the surface from which the electrode terminals 13 are led), and a battery side face (the surface with a smaller surface area than the large surface area and adjacent to the battery end face and the large surface area). The two opposing large surface areas can be formed as the second wall 10b and the first wall 10a, respectively. The two opposing battery side faces can be formed as either the second wall 10b or the first wall 10a. The surfaces can be formed as a first wall 10a and a second wall 10b, respectively. That is, in the embodiment where the outer shell 10 of the battery cell 100 is a quadrangular prism, the battery cell 100 can be a square battery (i.e., the orthographic projection outline of the outer shell 10 is square), such as a conventional square battery (shortest length), a short-blade battery (length greater than a square battery but less than a long-blade battery), or a long-blade battery (longest length). The first wall 10a can be the large surface of the battery, the side surface of the battery, or the end surface of the battery. In the embodiment where the battery cell 100 is formed as a cylindrical battery, the first wall 10a can be the end surface or the side surface of the cylindrical battery. In the embodiment where the first wall 10a is the side surface of the cylindrical battery, the gas storage structure 20 can also be provided on the side surface, such as in the gap between the side surface of the outer shell 10 and the electrode assembly 20 to avoid the tabs 21, adapters, and other structures.

[0226] Similarly, it can be understood that the electrode assembly has a large electrode assembly surface 24, an electrode assembly end surface 23, and an electrode assembly side surface 22. The large electrode assembly surface 24 is opposite to the large battery surface, the electrode assembly side surface 22 is opposite to the battery side surface, and the electrode assembly end surface 23 is opposite to the battery end surface.

[0227] As shown in Figures 5, 6, 7, 8 and 9, according to some embodiments of this application, a first insulating member 40a is provided between the second wall 10b and the electrode assembly 20, a gas storage structure 30 is disposed between the first insulating member 40a and the second wall 10b, and / or, the gas storage structure 30 is disposed between the first insulating member 40a and the electrode assembly 20.

[0228] Specifically, the first insulating member 40a is used for insulation protection between the electrode assembly 20 and the second wall 10b. A gas storage structure 30 can be provided between the second wall 10b and the first insulating member 40a, or between the first insulating member 40a and the electrode assembly 20, or on the side of the first insulating member 40a facing the second wall 10b and the side of the first insulating member 40a facing the electrode assembly 20. This allows for more placement positions of the gas storage structure 30, enabling it to come into more full contact with the gas generated inside the outer casing 10, thereby improving the gas absorption effect and effectively maintaining the internal pressure of the outer casing 10. This reduces the probability of a sharp increase in internal pressure and improves the stability and reliability of the battery cell 100.

[0229] It is understood that an insulating element can be provided between the electrode assembly 20 and the housing 10. The housing 10 may include a housing body and an end cap 11 covering the housing body. A lower plastic can be provided between the electrode assembly 20 and the end cap 11, and an insulating sheet can be provided between the electrode assembly 20 and the housing 12. In some embodiments, the end cap 11 of the battery cell 100 defines a second wall 10b, in which case the first insulating element 40a can be a lower plastic. In other embodiments, the housing 12 of the battery cell 100 defines a second wall 10b, in which case the first insulating element 40a can be an insulating sheet.

[0230] According to some embodiments of this application, the second wall 10b faces the side surface of the first insulating member 40a, and / or the side surface of the first insulating member 40a facing the second wall 10b is connected to the gas storage structure 30, and / or the electrode assembly 20 faces the side surface of the first insulating member 40a, and / or the side surface of the first insulating member 40a facing the electrode assembly 20 is connected to the gas storage structure 30.

[0231] For example, in embodiments where the gas storage structure 20 is disposed on the side surface of the second wall 10b facing the first insulating member 40a, or where the gas storage structure 20 is disposed on the side surface of the first insulating member 40a facing the second wall 10b, the influence of electrolyte level fluctuations on the gas storage structure 20 can be reduced. In embodiments where the gas storage structure 20 is disposed on the side surface of the first insulating member 40a facing the electrode assembly 20, or on the side surface of the first insulating member 40a facing the second wall 10b, the gas storage structure 20 can be assembled into the housing 10 simultaneously with the first insulating member 40a, which can reduce assembly difficulty. In embodiments where the gas storage structure 20 is disposed on the side surface of the electrode assembly 20 facing the first insulating member 40a, the electrode assembly 20 can be assembled simultaneously with the gas storage structure 20, which can also reduce assembly difficulty.

[0232] In other words, the gas storage structure 30 can be disposed on the second wall 10b, or on the side surface of the first insulating member 40a facing the second wall 10b, or on the side surface of the first insulating member 40a facing the electrode assembly 20, or on the side surface of the electrode assembly 20 facing the first insulating member 40a.

[0233] This allows for a larger area within the battery cell 100 used to fix the gas storage structure 30, which not only improves the stability and reliability of the gas storage structure 30 but also reduces the difficulty of setting up the gas storage structure 30 and increases the processing efficiency of the battery cell 100.

[0234] As shown in Figures 6, 7, 8 and 9, according to some embodiments of this application, a tab space is formed between the first insulating member 40a and the electrode assembly 20, the tab space accommodates the tab, and at least a partial gas storage structure 30 is provided in the tab space.

[0235] Among them, the surface of the first insulating member 40a facing the electrode assembly 20 forms an electrode space for accommodating the electrode tab 21 between the electrode assembly 20 and the electrode assembly 20, and at least a partial gas storage structure 30 is provided in the electrode space.

[0236] In other words, there is a gap between the first insulating member 40a and the electrode assembly 20, and this gap can define the tab space, in which at least a partial gas storage structure 30 can be provided.

[0237] In this way, the gap space inside the outer shell 10 can be fully utilized, which can not only improve the gas absorption capacity of the gas storage structure 30, but also limit the electrode assembly 20 through the gas storage structure 30, thereby improving the fixation stability and reliability of the electrode assembly 20 inside the outer shell 10.

[0238] In some embodiments, the tab space includes: a tab region a accommodating the tab 21 and a void region b located around the tab region a, wherein at least a portion of the gas storage structure 30 is disposed in the tab region a and / or the void region b.

[0239] In other words, in some embodiments, a gas storage structure 30 can be provided in the tab region a, and in other embodiments, a gas storage structure 30 can be provided in the gap region b. In a preferred embodiment, a gas storage structure 30 can be provided in both the tab region a and the gap region b.

[0240] It should be noted that the electrode assembly 20 includes one or more bare cells. The bare cells can be a wound structure (wound core) formed by stacking and winding positive electrode sheets, separator film and negative electrode sheets, or a stacked structure (stacked core) formed by stacking positive electrode sheets, separator film and negative electrode sheets, cutting and stacking them. The wound core or stacked core has tabs 21 leading out. The tabs 21 are connected to the electrode terminals 13 on the end cover 11. A lower plastic (i.e., the first insulating member 40a) can be provided between the electrode terminals 13 and the end cover 11. There is a gap between the lower plastic and the electrode assembly 20, and the tabs 21 are located in the gap. The corresponding gas storage structure 30 can also be provided in the gap and avoid the tabs 21.

[0241] For example, the gap between the lower plastic and the electrode assembly 20 can be divided into two parts. The first part is the part without the tab 21 (see Figures 6 and 8, i.e., gap region b), and the second part is the part with the tab 21 (see Figures 7 and 9, tab region a). The gap region b can be filled with the gas storage structure 30 in whole or in part, while the tab region a can be filled with the gas storage structure 30 while avoiding the tab 21.

[0242] In this way, the gas storage structure 30 is positioned more reasonably. On the one hand, it can be located between the electrolyte surface and the second wall 10b, so that the gas storage structure 30 can fully contact the gas generated inside the outer shell 10, thereby improving the absorption efficiency and absorption effect. On the other hand, it can make full use of the gap between the first insulating member 40a and the electrode assembly 20, thereby improving the space utilization rate. The overall volume of the gas storage structure 30 is larger, and the hydrogen absorption capacity is stronger, so that it can absorb more hydrogen and thus better maintain the stability of the internal pressure of the outer shell 10.

[0243] It should be noted that, as shown in Figures 6 and 8, the gas storage structure 30 is set in the gap region b, which can play an auxiliary supporting role for the electrode assembly 20, making the electrode assembly 20 more stable in the shell 10 and reducing the probability of movement. It can also improve the safety and reliability of the battery cell 100, as shown in Figures 7 and 9. The tab region a has a tab 21, and the gas storage structure 30 is set in the tab region a. While supporting and limiting the electrode assembly 20, it can also shape and limit the tab 21, preventing the tab 21 from being inserted into the shell, and further improving the reliability and stability of the electrode assembly 20.

[0244] Furthermore, within the tab region a, a gas storage structure 30 is provided in the gap between adjacent tabs 21, and / or in the gap between the tab 21 and the outer shell 20.

[0245] Specifically, the bare cell has a wound or stacked structure, and the tabs 21 of multiple positive electrode plates are connected to the positive terminal, and the tabs 21 of multiple negative electrode plates are connected to the negative terminal. There are gaps between the tabs 21 of multiple positive electrode plates and between the tabs 21 of multiple negative electrode plates. At least part of the gas storage structure 30 can be filled in these gaps. At the same time, there is also a gap between the tabs 21 and the outer casing 20, which can also be filled with the gas storage structure 30.

[0246] It is understandable that filling the gap between adjacent tabs 21 with a gas storage structure 30 can improve the air intake effect, support the tabs 21, reduce the deformation of the tabs 21, and improve the reliability and stability of the connection between the tabs 21 and the electrode terminal 13. Filling the gap between the tabs 21 and the outer shell 20 with a gas storage structure 30 can limit the tabs 21, reduce the movement of the tabs 21, and improve the reliability of the battery cell 100.

[0247] As shown in FIG5, according to some embodiments of the present application, the first insulating member 40a has a receiving cavity 41, which is open on the side facing the second wall 10b and / or on the side facing the electrode assembly 20 to receive the gas storage structure 30, and the receiving cavity 41 is in communication with the gap.

[0248] In other words, the first insulating member 40a can be used to achieve insulation between the end cap 11 and the electrode assembly 20. The first insulating member 40a can generally be formed into a plate structure, and one or more accommodating cavities 41 can be opened on the plate, and the gas storage structure 30 is disposed in the accommodating cavity 41.

[0249] Therefore, under the premise of absorbing the gas generated inside the outer shell 10, the gas storage structure 30 can be set inside the accommodating cavity 41 of the first insulating member 40a. Setting the gas storage structure 30 has less impact on the internal space of the outer shell 10 and can also take into account the energy density.

[0250] The lower plastic is located between the second wall 10b and the electrode assembly 20, and a gas storage structure 30 can be provided between the outer shell 10 and the lower plastic, and a gas storage structure 30 can also be provided between the lower plastic and the electrode assembly 20.

[0251] In other words, in some embodiments, the gas storage structure 30 is disposed between the lower plastic and the outer shell 10, in other embodiments, the gas storage structure 30 is disposed between the lower plastic and the electrode assembly 20, and in preferred embodiments, the gas storage structure 30 can be disposed between the lower plastic and the outer shell 10 and between the lower plastic and the electrode assembly 20.

[0252] Therefore, in the embodiment where the end cap 11 defines the second wall 10b, the gas storage structure 30 is disposed between the lower plastic and the outer shell 10, and / or between the lower plastic and the electrode assembly 20. The placement of the gas storage structure 30 is more reasonable, allowing more gas storage structures 30 to be located between the electrolyte surface and the second wall 10b, thereby improving the hydrogen absorption efficiency.

[0253] As shown in FIG5, according to some embodiments of the present application, the first insulating member 40a includes a limiting portion 42, which is located between the second wall 10b and the electrode assembly 20. The limiting portion 42 protrudes toward the electrode assembly 20 and pushes against the electrode assembly 20, and a receiving cavity is formed in the limiting portion 42.

[0254] That is, the lower plastic has a limiting part 42 for limiting the electrode assembly 20, and the limiting part 42 has a receiving cavity 41 on the side away from the electrode assembly 20, or the limiting part 42 has a receiving cavity 41 on the side facing the electrode assembly 20, and the gas storage structure 30 is disposed in the receiving cavity 41.

[0255] Specifically, the electrode assembly 20 has a positive electrode tab and a negative electrode tab, and the limiting part 42 on the lower plastic can include two limiting parts 42 located at both ends of the lower plastic. The multiple limiting parts 42 are used to press against and limit the electrode assembly 20, which can improve the fixing stability and reliability of the electrode assembly 20.

[0256] Furthermore, by setting the gas storage structure 30 within the accommodating cavity 41, on the one hand, there is no need to make major structural changes to the end cap 11 while setting the gas storage structure 30, and the thickness of the end cap 11 can remain unchanged to take into account the energy density of the battery cell 100. On the other hand, the gas storage structure 30 can be fixed by using the accommodating cavity 41 opened on the limiting part 42. The accommodating cavity 41 can limit the gas storage structure 30 to reduce the probability of the gas storage structure 30 shifting. The gas storage structure 30 is less affected by the fluctuation of the electrolyte level and can always be located above the electrolyte level, so that the absorption effect of the gas storage structure 30 is less affected by the fluctuation of the electrolyte and the effect of maintaining the internal pressure of the outer casing 10 is better.

[0257] Referring to Figure 5, according to some embodiments of this application, the second wall 10b is provided with an explosion-proof element 14, which is configured to break when the pressure inside the housing 10 reaches a set condition to release the gas inside the housing 10. The first insulating element 40a has a connecting portion for connecting the internal space of the housing 10 with the explosion-proof element 14, and at least a portion of the gas storage structure 30 is disposed in the connecting portion.

[0258] Among them, the explosion-proof component 14 is constructed as an explosion-proof valve, which can be assembled to the second wall 10b or integrally formed with the second wall 10b. A connecting part is formed on the first insulating component 40a. The connecting part is used to connect the internal space of the outer shell 10 with the outside. Therefore, the gas inside the outer shell 10 is suitable to enter the connecting part. The connecting part is provided with a corresponding gas storage structure 20, which can further increase the number of gas storage structures 20 to improve the gas intake effect and improve the space utilization rate.

[0259] It is understood that in some embodiments, the connecting portion is constructed as a connecting groove c formed on the first insulating member 40a. The connecting groove c extends along the side surface of the first insulating member 40a facing the electrode assembly 20 to the side surface of the first insulating member 40a away from the electrode assembly 20. This allows the gas inside the housing 10 to be discharged through the connecting groove c and the opened explosion-proof member 14 when the internal pressure of the housing 10 exceeds the pressure threshold that the explosion-proof member 14 can withstand, thereby realizing the timely release of the battery cell 100 and improving the reliability of the battery device 200.

[0260] Furthermore, a gas storage structure 30 can be further provided in the communicating groove c defined by the first insulating member 40a. The gas storage structure 30 can be provided in the first insulating member 40a to achieve gas absorption inside the outer casing 10. Under the premise of maintaining stable internal pressure, the internal space of the outer casing 10 can be fully utilized to improve the gas absorption effect while taking into account the energy density of the battery cell 100.

[0261] As shown in Figures 10 and 12, according to some embodiments of this application, a second insulating member 40b is provided between the third wall 10c and the electrode assembly 20, a gas storage structure 30 is disposed between the second insulating member 40b and the third wall 10c, and / or the gas storage structure 30 is disposed between the second insulating member 40b and the electrode assembly 20.

[0262] Specifically, the second insulating member 40b is used for insulation protection between the electrode assembly 20 and the third wall 10c. A gas storage structure 30 can be provided between the third wall 10c and the second insulating member 40b, or between the second insulating member 40b and the electrode assembly 20, or on the side of the second insulating member 40b facing the third wall 10c and the side of the second insulating member 40b facing the electrode assembly 20, so that there are more possible positions for the gas storage structure 30. The gas storage structure 30 can come into more full contact with the gas generated inside the outer casing 10, so as to improve the gas absorption effect.

[0263] It is understood that an insulating element can be provided between the electrode assembly 20 and the housing 10. The housing 10 may include a housing body and an end cap 11 covering the housing body. A lower plastic can be provided between the electrode assembly 20 and the end cap 11, and an insulating sheet can be provided between the electrode assembly 20 and the housing 12. In some embodiments, the end cap 11 of the battery cell 100 defines a third wall 10c, in which case the second insulating element 40b can be a lower plastic. In other embodiments, the housing 12 of the battery cell 100 defines a third wall 10c, in which case the second insulating element 40b can be an insulating sheet.

[0264] According to some embodiments of this application, the third wall 10c faces the side surface of the second insulating member 40b, and / or the side surface of the second insulating member 40b facing the third wall 10c is connected to the gas storage structure 30, and / or the electrode assembly 20 faces the side surface of the second insulating member 40b, and / or the side surface of the second insulating member 40b facing the electrode assembly 20 is connected to the gas storage structure 30.

[0265] For example, in embodiments where the gas storage structure 20 is disposed on the side surface of the third wall 10c facing the second insulating member 40b, or where the gas storage structure 20 is disposed on the side surface of the second insulating member 40b facing the third wall 10c, the influence of electrolyte level fluctuations on the gas storage structure 20 can be reduced. In embodiments where the gas storage structure 20 is disposed on the side surface of the second insulating member 40b facing the electrode assembly 20, and on the side surface of the second insulating member 40b facing the third wall 10c, the gas storage structure 20 can be assembled into the housing 10 simultaneously with the second insulating member 40b, which can reduce assembly difficulty. In embodiments where the gas storage structure 20 is disposed on the side surface of the electrode assembly 20 facing the second insulating member 40b, the electrode assembly 20 can be assembled simultaneously with the gas storage structure 20, which can also reduce assembly difficulty.

[0266] In other words, the gas storage structure 30 can be disposed on the third wall 10c, or on the side surface of the second insulating member 40b facing the third wall 10c, or on the side surface of the second insulating member 40b facing the electrode assembly 20, or on the side surface of the electrode assembly 20 facing the second insulating member 40b.

[0267] This allows for a larger area within the battery cell 100 used to fix the gas storage structure 30, which not only improves the stability and reliability of the gas storage structure 30 but also reduces the difficulty of setting up the gas storage structure 30 and increases the processing efficiency of the battery cell 100.

[0268] According to some embodiments of this application, the second insulating member 40b has a receiving cavity 41, which is open on the side facing the third wall 10c and / or on the side facing the electrode assembly 20 to receive the gas storage structure 30, and the receiving cavity 41 is in communication with the gap.

[0269] In other words, the second insulating member 40b can be used to achieve insulation between the end cap 11 and the electrode assembly 20. The second insulating member 40b can generally be formed into a plate structure, and one or more accommodating cavities 41 can be opened on the plate, and the gas storage structure 30 is disposed in the accommodating cavity 41.

[0270] Therefore, under the premise of absorbing the gas generated inside the outer shell 10, the gas storage structure 30 can be set inside the accommodating cavity 41 of the second insulating member 40b. Setting the gas storage structure 30 has less impact on the internal space of the outer shell 10 and can also take into account the energy density.

[0271] The lower plastic is located between the third wall 10c and the electrode assembly 20, and a gas storage structure 30 can be provided between the outer shell 10 and the lower plastic, and a gas storage structure 30 can also be provided between the lower plastic and the electrode assembly 20.

[0272] In other words, in some embodiments, the gas storage structure 30 is disposed between the lower plastic and the outer shell 10, in other embodiments, the gas storage structure 30 is disposed between the lower plastic and the electrode assembly 20, and in preferred embodiments, the gas storage structure 30 can be disposed between the lower plastic and the outer shell 10 and between the lower plastic and the electrode assembly 20.

[0273] Therefore, in the embodiment where the end cap 11 defines the third wall 10c, the gas storage structure 30 is disposed between the lower plastic and the outer shell 10, and / or between the lower plastic and the electrode assembly 20. The placement of the gas storage structure 30 is more reasonable, allowing more gas storage structures 30 to be located between the electrolyte surface and the second wall 10b, thereby improving the hydrogen absorption efficiency.

[0274] According to some embodiments of this application, the second insulating member 40b includes a limiting portion 42, which is located between the third wall 10c and the electrode assembly 20. The limiting portion 42 protrudes toward the electrode assembly 20 and pushes against the electrode assembly 20; a receiving cavity 41 is formed in the limiting portion 42.

[0275] That is, the lower plastic has a limiting part 42 for limiting the electrode assembly 20, and the limiting part 42 has a receiving cavity 41 on the side away from the electrode assembly 20, or the limiting part 42 has a receiving cavity 41 on the side facing the electrode assembly 20, and the gas storage structure 30 is disposed in the receiving cavity 41.

[0276] Specifically, the electrode assembly 20 has a positive electrode tab and a negative electrode tab, and the limiting part 42 on the lower plastic can include two limiting parts 42 located at both ends of the lower plastic. The multiple limiting parts 42 are used to press against and limit the electrode assembly 20, which can improve the fixing stability and reliability of the electrode assembly 20.

[0277] Furthermore, by setting the gas storage structure 30 within the accommodating cavity 41, on the one hand, there is no need to make major structural changes to the end cap 11 while setting the gas storage structure 30, and the thickness of the end cap 11 can remain unchanged to take into account the energy density of the battery cell 100. On the other hand, the gas storage structure 30 can be fixed by using the accommodating cavity 41 opened on the limiting part 42. The accommodating cavity 41 can limit the gas storage structure 30 to reduce the probability of the gas storage structure 30 shifting. The gas storage structure 30 is less affected by the fluctuation of the electrolyte level and can always be located above the electrolyte level, so that the absorption effect of the gas storage structure 30 is less affected by the fluctuation of the electrolyte and the effect of maintaining the internal pressure of the outer casing 10 is better.

[0278] According to some embodiments of this application, a tab space is formed between the second insulating member 40b and the electrode assembly 20, the tab space accommodates the tab 21, and at least a partial gas storage structure 30 is provided in the tab space.

[0279] Among them, the second insulating member 40b forms an electrode space for accommodating the electrode tab 21 between its side surface facing the electrode assembly 20 and the electrode assembly 20, and at least a partial gas storage structure 30 is provided in the electrode space.

[0280] In other words, there is a gap between the second insulating member 40b and the electrode assembly 20, and this gap can define the tab space, in which at least a partial gas storage structure 30 can be provided.

[0281] In this way, the gap space inside the outer shell 10 can be fully utilized, which can not only improve the gas absorption capacity of the gas storage structure 30, but also limit the electrode assembly 20 through the gas storage structure 30, thereby improving the fixation stability and reliability of the electrode assembly 20 inside the outer shell 10.

[0282] According to some embodiments of this application, the electrode space includes: a folded electrode region a that accommodates the electrode 21 and a void region b located around the folded electrode region a, with at least a portion of the gas storage structure 30 disposed in the void region b.

[0283] It should be noted that the tab 21 is connected to the electrode terminal 13 on the end cover 11. A lower plastic (i.e., the second insulating part 40b) can be provided between the electrode terminal 13 and the end cover 11. There is a gap between the lower plastic and the electrode assembly 20, and the tab 21 is located in the gap. The corresponding gas storage structure 30 can also be provided in the gap, while avoiding the tab 21.

[0284] For example, the gap between the lower plastic and the electrode assembly 20 can be divided into two parts: the first part is the part without the tab 21, and the second part is the part with the tab 21. The gap region b can be filled with the gas storage structure 30 in whole or in part, while the tab region a is located below the electrolyte surface, so the tab region a is not provided with the gas storage structure 30.

[0285] In this way, the gas storage structure 30 is positioned more reasonably. On the one hand, it can be located between the electrolyte surface and the third wall 10c, so that the gas storage structure 30 can fully contact the gas generated inside the outer shell 10, thereby improving the absorption efficiency and absorption effect. On the other hand, it can make full use of the gap between the second insulating member 40b and the electrode assembly 20, thereby improving the space utilization rate. The overall volume of the gas storage structure 30 is larger, and its hydrogen absorption capacity is stronger, allowing it to absorb more hydrogen and thus better maintain the stability of the internal pressure of the outer shell 10.

[0286] It should be noted that the gas storage structure 30 located between the third wall 10c and the electrode assembly 20 is disposed adjacent to the second wall 10b, and the maximum distance between it and the second wall 10b is less than or equal to 5mm.

[0287] Specifically, a gap is formed between the electrode assembly 20 and the housing 10, and a portion of the gap is used to contain the electrolyte. The other portion of the gap includes: a first other portion defined by the second wall 10b and the area opposite to the electrode assembly 20, and a second other portion defined by the electrode assembly 20 and the third wall 10c. The second other portion is the portion defined by the third wall 10c and the electrode assembly 20, which is located side-up in the placement direction and above the electrolyte based on the placement direction of the battery cell 100.

[0288] Therefore, the gas storage structure 30 located between the third wall 10c and the electrode assembly 20 is positioned adjacent to the second wall 10b, i.e., above it, and the maximum distance between it and the second wall 10b is less than or equal to 5mm, so as to ensure that the gas storage structure 30 located between the third wall 10c and the electrode assembly 20 can be positioned above the electrolyte surface, thereby improving the gas intake effect and gas intake efficiency.

[0289] For example, as shown in Figures 10 and 12, the gas storage structure 30 disposed between the third wall 10c and the electrode assembly 20 is adjacent to the second wall 10b, and the maximum distance L1 between the structure and the second wall 10b is less than or equal to 5 mm.

[0290] As shown in Figure 10, in the second embodiment, the large surface of the battery defines the second wall 10b, the end face of the battery defines the third wall 10c, and the second insulating member 40b is a lower plastic. The maximum distance between the gas storage structure 30 disposed on the lower plastic near the second wall 10b and the second wall 10b can be 1mm, 2mm, 3mm, 4mm, 5mm, etc. With this arrangement, when the electrolyte is not fluctuating, the gas storage structure 30 can be entirely or at least partially located above the electrolyte surface. When the electrolyte surface fluctuates, the gas storage structure 30 is less affected by the fluctuation, and a larger portion of the gas storage structure 30 can be located above the electrolyte surface to ensure a stable and reliable hydrogen absorption effect.

[0291] As shown in Figure 12, in the third embodiment, a second wall 10b is defined on the side of the battery, a third wall 10c is defined on the end face of the battery, and the second insulating member 40b is a lower plastic. The maximum distance between the gas storage structure 30 disposed on the lower plastic near the second wall 10b and the second wall 10b can be 1mm, 2mm, 3mm, 4mm, 5mm, etc. With this configuration, when the electrolyte is not fluctuating, the gas storage structure 30 can be entirely or at least partially located above the electrolyte surface. When the electrolyte surface fluctuates, the gas storage structure 30 is less affected by the fluctuation, and a larger portion of the gas storage structure 30 can be located above the electrolyte surface to ensure a stable and reliable hydrogen absorption effect.

[0292] As shown in Figure 2, this application proposes a battery device 200, including: the battery cell 100 in the above embodiment.

[0293] According to the battery device 200 of the present application embodiment, a battery cell 100 is provided inside the housing 600, and a gas storage structure 30 is integrated inside the battery cell 100. The internal pressure of the battery cell 100 is more stable, and less hydrogen is emitted into the housing 600 during operation. This not only improves the service life of the battery device 200, but also improves the safety and reliability of the battery device 200 and reduces safety hazards.

[0294] As shown in Figure 3, this application provides an electrical device 300, including the battery device 200 in the above embodiment.

[0295] Referring to Figure 2, the battery device 200 has a housing 600, and the battery cells 100 can be arranged in an array within the housing 600. In embodiments where the battery cells 100 are constructed as square batteries in the vertical direction of the housing 600, the battery cells 100 can be arranged with the end cap 11 facing upward within the housing 600, and the gas storage structure 30 can be disposed between the end cap 11 and the electrode assembly 20, or disposed within the end cap 11. Alternatively, the battery cells 100 can be arranged with their battery sides facing upward within the housing 600, and the gas storage structure 30 can be disposed between the first side plate and the electrode assembly 20, or between the first side plate defining the second wall 10b near the end cap 11 and the electrode assembly 20. Alternatively, the battery cells 100 can be arranged with their battery sides facing upward within the housing 600, and the gas storage structure 30 can be disposed between the second side plate and the electrode assembly 20, or between the second side plate defining the second wall 10b near the end cap 11 and the electrode assembly 20.

[0296] Of course, the battery cell 100 can also be constructed as a cylindrical battery, with the axis of the cylindrical battery parallel to the vertical direction, and a gas storage structure 30 can be set inside the end cap 11 located on the top of the cylindrical battery.

[0297] The battery cell 100 of the present application embodiment will be described in detail below with reference to Figures 5-22.

[0298] First embodiment:

[0299] As shown in Figures 5, 6, 7, 8 and 9, in the first embodiment, the battery cell 100 is constructed as a square battery, the second wall 10b leads out the electrode terminal 13 and is defined by the end cap 11, the third wall 10c is the side of the battery and the large surface of the battery, the first insulating member 40a is the lower plastic and the second insulating member 40b is the insulating sheet.

[0300] The lower plastic has a accommodating cavity 41 in the limiting part 42 at both ends, and an exhaust channel facing the explosion-proof part 14 on the lower plastic. An electrode tab space is formed between the lower plastic and the electrode assembly 20. The electrode tab space includes a gap area b and a folded electrode tab area a. A gas storage structure 30 is set in the accommodating cavity 41, the exhaust channel, the gap area b and the folded electrode tab area a. A gas storage structure 30 is also set between the insulating sheet and the third wall 10c and between the insulating sheet and the electrode assembly 20.

[0301] Second embodiment:

[0302] As shown in Figures 10 and 11, in the second embodiment, the battery cell 100 is constructed as a square battery, the third wall 10c leads out the electrode terminal 13, and the second wall 10b is defined by the large surface of the battery. The third wall 10c is defined by the end cap 11. The first insulating member 40a is an insulating sheet, and the second insulating member 40b is a lower plastic.

[0303] The lower plastic has a accommodating cavity 41 in the limiting part 42 at both ends, and an electrode tab space is formed between the lower plastic and the electrode assembly 20. The electrode tab space includes a gap region b and a folded electrode tab region a. The gas storage structure 30 is provided in the accommodating cavity 41 and the gap region b adjacent to the second wall 10b. Gas storage structures 30 are also provided between the insulating sheet and the second wall 10b and between the insulating sheet and the electrode assembly 20.

[0304] As shown in Figures 12 and 13, in the third embodiment, the battery cell 100 is constructed as a square battery, the third wall 10c leads out the electrode terminal 13, and the second wall 10b is defined by the side of the battery. The third wall 10c is defined by the end cap 11. The first insulating member 40a is an insulating sheet, and the second insulating member 40b is a lower plastic.

[0305] The lower plastic has a accommodating cavity 41 in the limiting part 42 at both ends, and an electrode tab space is formed between the lower plastic and the electrode assembly 20. The electrode tab space includes a gap region b and a folded electrode tab region a. The gas storage structure 30 is provided in the accommodating cavity 41 and the gap region b adjacent to the second wall 10b. Gas storage structures 30 are also provided between the insulating sheet and the second wall 10b and between the insulating sheet and the electrode assembly 20.

[0306] As shown in Figures 14 and 15, in the fourth embodiment, the battery cell 100 is constructed as a square battery, the first wall 10a leads out the electrode terminal 13, the first insulating member 40a and the second insulating member 40b are both constructed as insulating sheets, and gas storage structures 30 are provided between the insulating sheet and the second wall 10b, between the insulating sheet and the third wall 10c, and between the insulating sheet and the electrode assembly 20, and the gas storage structure 30 between the third wall 10c and the electrode assembly 20 is located adjacent to the second wall 10b.

[0307] As shown in Figures 16 and 17, in the fifth embodiment, the battery cell 100 is constructed as a short-blade battery or a long-blade battery, the third wall 10c leads out the electrode terminal 13, the large surface of the battery defines the second wall 10b, the second insulating member 40b is constructed as a lower plastic, and the first insulating member 40a is constructed as an insulating sheet.

[0308] The lower plastic has limiting portions 42 at both ends of its length. Each limiting portion 42 has a receiving cavity 41. The receiving cavity 41 has a baffle 411 extending along the width direction of the lower plastic. The baffle 411 divides the lower plastic into multiple cavities. One or more cavities adjacent to the second wall 10b are provided with a gas storage structure 30. Gas storage structures 30 are also provided between the second wall 10b and the insulating sheet, and between the insulating sheet and the electrode assembly 20.

[0309] As shown in Figures 18 and 19, in the fifth embodiment, the battery cell 100 is constructed as a short-blade battery or a long-blade battery, the third wall 10c leads out the electrode terminal 13, the side of the battery defines the second wall 10b, the second insulating member 40b is constructed as lower plastic, and the first insulating member 40a is constructed as an insulating sheet.

[0310] The lower plastic has limiting portions 42 at both ends of its length. Each limiting portion 42 has a receiving cavity 41. The receiving cavity 41 has a baffle 411 extending along the length of the lower plastic. The baffle 411 divides the lower plastic into multiple cavities. A gas storage structure 30 is provided in one or more cavities adjacent to the second wall 10b. Gas storage structures 30 are also provided between the second wall 10b and the insulating sheet, and between the insulating sheet and the electrode assembly 20.

[0311] As shown in Figure 20, in the sixth embodiment, the battery cell 100 is constructed as a short-blade battery or a long-blade battery, the third wall 10c leads out the electrode terminal 13, the side of the battery or the large surface of the battery defines the second wall 10b, and the first insulating member 40a is constructed as an insulating sheet.

[0312] Among them, a gas storage structure 30 is also provided between the second wall 10b and the insulating sheet, and between the insulating sheet and the electrode assembly 20.

[0313] As shown in Figures 21 and 22, in the seventh embodiment, the battery cell 100 is constructed as a cylindrical battery, the second wall 10b leads out the electrode terminal 13, and the end cap 11 defines the second wall 10b. The first insulating member 40a is constructed as a lower plastic.

[0314] The end cap 11 has multiple limiting parts 42, and each of the multiple limiting parts 42 is equipped with a gas storage structure 30.

[0315] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0316] Example 1

[0317] Preparation of hydrogen storage alloys:

[0318] Rare earth metals La, Ni, Mg, and Ti were selected.

[0319] According to the molar ratio, the weighed bulk metal is placed in a zirconia crucible according to the designed process. The vacuum induction melting furnace is evacuated to a vacuum level of 1×10⁻⁶ before heating. -3The pressure was increased to above 100 MPa; then, 0.05 MPa of inert argon gas was introduced into the furnace as a protective gas; the heating temperature was adjusted to 1500℃; the liquid alloy was held at the molten state for 5 minutes; then, the uniformly mixed liquid metal was poured into a copper mold, cooled to room temperature in the furnace, and removed to obtain the master alloy ingot LaNi. 6.2 Mg 0.2 Ti 0.8 The hydrogen storage alloy powder was obtained by grinding. The volume average particle size (Dv50) of the hydrogen storage alloy was 5 μm, and the BET specific surface area was 7.9 m². 2 / g.

[0320] The hydrogen storage alloy powder was placed into a plastic-sealed bag made of polyethylene with an air permeability of 250s / 100mL.

[0321] 1. Preparation of positive electrode sheet

[0322] The positive electrode active material sodium iron pyrophosphate (NFPP), conductive agent carbon black (Super P), and binder polyvinylidene fluoride (PVDF) were thoroughly mixed in an appropriate amount of NMP solvent at a weight ratio of 90:5:5 to form a uniform positive electrode slurry. The positive electrode slurry was then coated onto the surface of the positive electrode current collector aluminum foil at a coating weight of 20 mg / cm². 2 After drying and cold pressing, a positive electrode sheet is obtained.

[0323] 2. Preparation of negative electrode sheet

[0324] Carbon nanotubes (CNTs) and sodium carboxymethyl cellulose (CMC) were thoroughly mixed in deionized water at a weight ratio of 50:50 to form an interface modification layer slurry. The interface modification layer slurry was then coated onto the surface of the negative electrode current collector copper foil (8 μm thick), with a single-sided thickness of 5 μm.

[0325] 3. Preparation of electrolyte

[0326] Sodium hexafluorophosphate (NaPF6) was added to diethylene glycol dimethyl ether in an argon-filled glove box with a water content of <1 ppm and stirred until homogeneous, resulting in an electrolyte with a NaPF6 concentration of 1.0 mol / L.

[0327] 4. Separating membrane

[0328] Polyethylene film is used as the separation membrane.

[0329] 5. Preparation of secondary batteries

[0330] The positive electrode, separator, and negative electrode obtained in the above steps are stacked in sequence, with the separator positioned between the positive and negative electrode to isolate them. The stacked components are then wound to form a battery cell. The battery cell is then installed in a casing, and a plastic bag containing hydrogen storage alloy powder is fixed to the underside of the top cover, adjacent to the tabs and occupying the lower plastic space. The amount of hydrogen storage alloy added is 0.4 g / Ah. After drying, electrolyte is injected. After formation and settling processes, the battery cell is obtained. After further assembly, electrolyte injection, formation aging, and other steps, the battery cell is produced.

[0331] The preparation methods of sodium-ion batteries in Examples 2-15 and Comparative Example 1 are the same as those in Example 1, except that the process of preparing the hydrogen storage alloy is different. Examples 2-8 are adjusted according to the different elements and ratios of the hydrogen storage alloy compared to Example 1, as shown in Table 1.

[0332] In Comparative Example 1, no hydrogen storage alloy was prepared, and no hydrogen storage alloy was placed in the battery. The hydrogen absorption pressure of Comparative Examples 2 and 3 is not within the range of this application.

[0333] Table 1

[0334] Example 16

[0335] Preparation of hydrogen storage alloys:

[0336] Same as Example 1.

[0337] 1. Preparation of positive electrode sheet

[0338] Lithium iron phosphate (LiFePO4), carbon nanotubes (CNTs), and metahexafluorophosphate (PHPF) were thoroughly mixed in N-methylpyrrolidone (NMP) at a mass ratio of 95:2:3 to form a uniform positive electrode slurry. This slurry was then coated onto the surface of a 15 μm thick aluminum foil current collector. After drying, cold pressing, and die-cutting, a 239 μm thick positive electrode sheet was obtained, with a single-sided thickness of 112 μm for the positive electrode active material layer. The coating weight of the positive electrode active material layer on the positive electrode sheet was 20 mg / cm³. 2 .

[0339] 2. Preparation of negative electrode sheet

[0340] The negative electrode active material hard carbon, conductive agent carbon black, and binder sodium carboxymethyl cellulose were thoroughly mixed in a deionized water solvent system at a mass ratio of 90:5:5 to obtain a negative electrode slurry. The negative electrode slurry was uniformly coated onto the negative electrode current collector copper foil. After the copper foil was dried at room temperature, it was transferred to a 120℃ oven to dry for 1 hour. Then, it was cold-pressed and slit to obtain a negative electrode sheet. Finally, the negative electrode sheet was printed to obtain the final electrode sheet.

[0341] 3. Preparation of electrolyte

[0342] In an argon-filled glove box with a water content of <1ppm, diethylene glycol dimethyl ether and tetrahydrofuran were mixed at a mass ratio of 1:3, and lithium hexafluorophosphate (LiPF6) was added. After stirring evenly, an electrolyte with a LiPF6 concentration of 1.0mol / L was obtained.

[0343] 4. Separating membrane

[0344] Polyethylene film is used as the separation membrane.

[0345] 5. Preparation of secondary batteries

[0346] The positive electrode, separator, and negative electrode obtained in the above steps are stacked in sequence, with the separator positioned between the positive and negative electrode to isolate them. The stacked components are then wound to form a battery cell. The battery cell is then installed in a casing, and a plastic bag containing hydrogen storage alloy powder is fixed to the underside of the top cover, adjacent to the tabs and occupying the lower plastic space. The amount of hydrogen storage alloy added is 0.4 g / Ah. After drying, electrolyte is injected. After formation and settling processes, the battery cell is obtained. After further assembly, electrolyte injection, formation aging, and other steps, the battery cell is produced.

[0347] The lithium-ion batteries of Examples 17-20 and Comparative Examples 4-6 were prepared using the same methods as those of Example 15, except that the battery preparation process was different.

[0348] In Comparative Example 4, no hydrogen storage alloy was prepared, and no hydrogen storage alloy was set in the secondary battery. The hydrogen absorption pressure of Comparative Examples 5 and 6 is not within the range of this application, as shown in Table 2.

[0349] Table 2

[0350] It is understandable that in Tables 1 and 2, the hydrogen absorption pressure of the hydrogen storage alloy refers to the pressure at which the hydrogen storage alloy begins to absorb hydrogen, which is the minimum hydrogen absorption pressure.

[0351] The secondary batteries of Examples 1-20 and Comparative Examples 1-6 were subjected to hot box tests to determine the failure temperature and the hydrogen content at failure. The characterization results are shown in Table 3.

[0352] 1. Place the secondary battery in a pressure vessel and conduct a stepped temperature rise-isothermal test to determine the failure temperature boundary and holding time. After the secondary battery fails, take samples of the gas from the pressure vessel to determine its composition.

[0353] (1) Secondary battery state: 100% SOC; Test secondary battery temperature: 22±5℃;

[0354] (2) Temperature sensing wire arrangement: arranged on the positive and negative terminals of the secondary battery casing, and at four points in the center of the large surface of the top cover and the large surface of the side of the secondary battery; multi-channel acquisition frequency: ≤0.1s;

[0355] (3) Assembly fixture: The fixture surface and screw must be insulated with Teflon; the fixture force is 3000N, the fixture must completely cover the large surface of the secondary battery, and the upper surface of the fixture is flush with the top cover of the secondary battery; the bottom of the secondary battery is suspended (10-20mm); the interface of the large surface of the secondary battery: fixture-secondary battery-fixture;

[0356] (4) Test procedure: Heat up to 60°C at a rate of 5°C / min and hold for 5 hours. Then, heat up to 5°C and hold for 30 minutes until the secondary battery thermally runs out of control or 24 hours.

[0357] 2. Gas composition analysis test: Gas chromatography-mass spectrometry (equipment model: 7890B-5977), gas composition analysis, detection standard, GB / T 9722-2006, sampling volume 1mL;

[0358] 1. Manual injection: If the gas composition is oxygen and nitrogen in a 1:4 ratio, the sample is introduced into the air; otherwise, it is not.

[0359] 2. Used to test the gas composition in secondary batteries; the detector is a TCD.

[0360] 3. The qualitative method is based on the retention time of the standard gas.

[0361] 4. The quantitative method was peak area normalization, and the results are shown in Table 3.

[0362] Table 3

[0363] As can be seen from Table 3, in the sodium secondary batteries of Examples 1-15 of this application, a hydrogen storage alloy with a hydrogen absorption pressure of 0.3MPa-0.5MPa is added to the battery, resulting in a higher failure temperature and a lower proportion of hydrogen gas at failure. Compared with Examples 1-15, the sodium secondary battery of Comparative Example 1 does not use a hydrogen storage alloy, and the hydrogen absorption pressures of Comparative Examples 2 and 3 are not within the range of this application. The failure temperature of the sodium secondary battery is lower, and the proportion of hydrogen gas at failure is significantly higher.

[0364] In the lithium secondary batteries of Examples 16-20 of this application, a hydrogen storage alloy with a hydrogen absorption pressure of 0.3MPa-0.5MPa is added to the battery. The failure temperature of the secondary battery is relatively high, and the proportion of hydrogen gas at failure is relatively low. Compared with Examples 16-20, the lithium secondary battery of Comparative Example 4 does not use a hydrogen storage alloy, and the hydrogen absorption pressure of Comparative Examples 5 and 6 is not within the range of this application. The failure temperature of the lithium secondary battery is lower, and the proportion of hydrogen gas at failure is significantly higher.

[0365] As can be seen, the secondary battery in this application embodiment includes a hydrogen storage alloy. The hydrogen storage alloy can absorb the hydrogen gas generated by the battery at 0.3MPa-0.5MPa, and can absorb the flammable hydrogen gas inside the secondary battery before thermal runaway, thereby reducing the risk of thermal runaway of the secondary battery.

[0366] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A secondary battery, wherein, The secondary battery includes a battery body and a casing for housing the battery body. The battery body includes a positive electrode, an electrolyte, and a negative electrode. A plastic sealing bag is provided between the battery body and the outer shell. The plastic sealing bag contains hydrogen storage alloy powder, and the hydrogen absorption pressure of the hydrogen storage alloy is 0.3MPa-0.5MPa.

2. The secondary battery according to claim 1, wherein, The volume average particle size Dv50 of the hydrogen storage alloy is 2μm-25μm.

3. The secondary battery according to claim 1 or 2, wherein, The volume average particle size Dv50 of the hydrogen storage alloy is 2μm-10μm.

4. The secondary battery according to any one of claims 1-3, wherein, The BET specific surface area of ​​the hydrogen storage alloy is 1 m². 2 / g-10m 2 / g.

5. The secondary battery according to any one of claims 1-4, wherein, The BET specific surface area of ​​the hydrogen storage alloy is 5m². 2 / g-10m 2 / g.

6. The secondary battery according to any one of claims 1-5, wherein, The air permeability of the sealed bag is 100s / 100mL-1000s / 100mL.

7. The secondary battery according to any one of claims 1-6, wherein, The air permeability of the sealed bag is 100s / 100mL-500s / 100mL.

8. The secondary battery according to any one of claims 1-7, wherein, The material of the plastic sealing bag includes at least one of polyethylene, polypropylene, EPDM rubber, or nitrile rubber.

9. The secondary battery according to any one of claims 1-8, wherein, In the secondary battery, the amount of hydrogen storage alloy added is 0.005 g / Ah to 2.4 g / Ah.

10. The secondary battery according to any one of claims 1-9, wherein, In the secondary battery, the amount of hydrogen storage alloy added is 0.04 g / Ah to 0.8 g / Ah.

11. The secondary battery according to any one of claims 1-10, wherein, The negative electrode sheet includes a negative current collector and an interface modification layer disposed on at least one side of the negative current collector, the interface modification layer including an adhesive and a conductive agent.

12. The secondary battery according to claim 11, wherein, The thickness of the interface modification layer is 0.5μm-5μm.

13. The secondary battery according to any one of claims 1-12, wherein, The electrolyte includes a solvent, which includes at least one of an ether solvent or an ester solvent.

14. The secondary battery according to claim 13, wherein, The solvent includes ether solvents, which include at least one of 1,2-dimethoxypropane, dimethoxymethane, ethylene glycol dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, pentaethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, or 1,3-dioxopentane.

15. The secondary battery according to any one of claims 1-14, wherein, The hydrogen storage alloy includes magnesium-based alloys, titanium-based alloys, or LaNi alloys. y M z At least one of them, Wherein, M includes at least one of Zr, Mn, Mg, Zn, Al, Ti, Fe, Cu, Co, Bi or Ca, 2≤y≤9, 1≤z≤5, and 7≤y+z≤9.

16. The secondary battery according to claim 15, wherein, The secondary battery satisfies at least one of the following conditions: The magnesium alloy and / or the titanium alloy contain iron. M includes at least one of Ti, Mn, Mg, Zr, Bi, or Fe; The titanium alloy includes TiNi. 0.5 Fe 0.5 or Ti2Ni 0.5 Fe 0.5 At least one of them; The magnesium alloy includes Mg2Ni 0.5 Fe 0.5 Mg2Al 0.5 Fe 0.5 Mg2Cr 0.5 Fe 0.5 or Mg2Te 0.5 Fe 0.5 At least one of them.

17. The secondary battery according to any one of claims 1-16, wherein, The hydrogen storage alloy includes LaNi 6.2 Mg 0.2 Ti 0.8 LaNi 5.5 Mn 0.6 Fe 0.4 Bi 0.5 LaNi 7.5 Mn 0.2 Fe 0.4 Bi 0.9 LaNi2Ti 3.5 Fe 0.4 Zr 0.5 Bi 0.6 LaNi9, LaNi7, TiNi 0.5 Fe 0.5 or Mg2Ni 0.5 Fe 0.5 At least one of them.

18. The secondary battery according to any one of claims 1-17, wherein, The battery body includes: An electrode assembly includes the positive electrode and the negative electrode, the electrode assembly is housed within the housing, and a gap is formed between the electrode assembly and the housing; An electrolyte, comprising an electrolyte solution contained within the housing, a portion of which is immersed in the electrode assembly, and a portion of which is contained within a portion of the gap; A gas storage structure, housed within the outer casing, wherein at least a portion of the gas storage structure is located in the other portion of the gap, and at least a portion of the gas storage structure is the hydrogen storage alloy.

19. The secondary battery as claimed in claim 18, wherein, The housing includes a first wall and a second wall, which are disposed opposite to each other. The first wall supports the electrode assembly, and at least a portion of the gap is formed between the second wall and the electrode assembly. At least a portion of the gas storage structure is disposed between the electrode assembly and the second wall.

20. The secondary battery according to claim 19, wherein, A first insulating element is provided between the second wall and the electrode assembly; The gas storage structure is disposed between the first insulating member and the second wall, and / or the gas storage structure is disposed between the first insulating member and the electrode assembly.

21. The secondary battery according to claim 20, wherein, The second wall faces the side surface of the first insulator, and / or the side surface of the first insulator facing the second wall is connected to the gas storage structure, and / or the electrode assembly faces the side surface of the first insulator, and / or the side surface of the first insulator facing the electrode assembly is connected to the gas storage structure.

22. The secondary battery according to claim 20, wherein, An electrode space is formed between the first insulating member and the electrode assembly, the electrode space accommodating the electrode, and at least a portion of the gas storage structure is provided within the electrode space.

23. The secondary battery according to claim 22, wherein, The electrode space includes: a folded electrode region accommodating the electrode and a void region located around the folded electrode region, at least a portion of the gas storage structure is disposed in the folded electrode region, and / or the void region.

24. The secondary battery according to claim 23, wherein, Within the area of ​​the folded tab, the gas storage structure is provided in the gap between adjacent tabs and / or in the gap between the tab and the outer shell.

25. The secondary battery according to claim 20, wherein, The first insulating member has a receiving cavity that is open to one side of the second wall and / or to one side of the electrode assembly to receive the gas storage structure, and the receiving cavity is in communication with the gap.

26. The secondary battery according to claim 25, wherein, The first insulating member includes a limiting portion that protrudes toward the electrode assembly, and the accommodating cavity is formed in the limiting portion.

27. The secondary battery according to claim 20, wherein, The second wall is provided with an explosion-proof component, which is configured to rupture when the pressure inside the housing reaches a set condition to release the gas inside the housing. The first insulating component has a connecting portion for connecting the internal space of the housing with the explosion-proof component, and at least a portion of the gas storage structure is disposed in the connecting portion.

28. The secondary battery according to claim 27, wherein, The connecting portion is constructed as a connecting groove formed on the first insulating member, the connecting groove extending along the side surface of the first insulating member facing the electrode assembly to the side surface of the first insulating member away from the electrode assembly.

29. The secondary battery according to claim 19, wherein, The outer casing has a third wall, which is connected to the first wall and the second wall respectively, and at least part of the gas storage structure is disposed between the third wall and the electrode assembly.

30. The secondary battery according to claim 29, wherein, A second insulating element is provided between the third wall and the electrode assembly, and the gas storage structure is disposed between the second insulating element and the third wall, and / or, the gas storage structure is disposed between the second insulating element and the electrode assembly.

31. The secondary battery according to claim 30, wherein, The third wall has a side surface facing the second insulator, and / or the second insulator has a side surface facing the third wall that is connected to the gas storage structure, and / or the electrode assembly has a side surface facing the second insulator, and / or the second insulator has a side surface facing the electrode assembly that is connected to the gas storage structure.

32. The secondary battery according to claim 30, wherein, The second insulating member has a receiving cavity that is open to the side facing the third wall and / or the side facing the electrode assembly to receive the gas storage structure, and the receiving cavity is in communication with the gap.

33. The secondary battery according to claim 32, wherein, The second insulating member includes a limiting portion that protrudes toward the electrode assembly, and the accommodating cavity is formed in the limiting portion.

34. The secondary battery according to claim 30, wherein, A tab space is formed between the second insulating member and the electrode assembly, the tab space accommodates the tab, and at least a portion of the gas storage structure is provided in the tab space.

35. The secondary battery according to claim 34, wherein, The electrode space includes: a folded electrode region for accommodating the electrode and a void region located around the folded electrode region, with at least a portion of the gas storage structure disposed in the void region.

36. The secondary battery according to any one of claims 29-35, wherein, The gas storage structure located between the third wall and the electrode assembly is disposed adjacent to the second wall, and the maximum distance between the gas storage structure and the second wall is less than or equal to 5 mm.

37. An electrical appliance, wherein, The secondary battery includes any one of claims 1-36.

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