A battery cell, a battery, and an electric device

Abstract

The application provides a battery cell, a battery and a power utilization device. The battery cell comprises a housing assembly, wherein the housing assembly comprises a pressure relief device and a gas generating coating; the gas generating coating is arranged on at least one inner surface of the housing assembly; and the gas generating coating comprises a gas generating agent, the gas generating agent comprising an auxiliary gas generating agent and an organic compound gas generating agent, the auxiliary gas generating agent comprising an inorganic compound gas generating agent and / or an oxalate compound. The battery cell of the application can brake the pressure relief device at a lower internal temperature in the early stage of abnormal heat generation inside the battery cell, so as to reduce the temperature and / or pressure inside the battery cell in advance, and further reduce the risk of thermal runaway of the battery cell.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Technology

[0002] In the design of battery cells, if the internal temperature of a battery cell rises abnormally, the internal pressure may also increase rapidly, potentially increasing the risk of thermal runaway. Therefore, how to provide a battery cell that reduces the risk of thermal runaway is a pressing technical problem that needs to be solved. Summary of the Invention

[0003] This application is made in view of the above-mentioned issues, and its purpose is to provide a battery cell, battery and power device that can reduce the risk of thermal runaway.

[0004] To achieve the above objectives, this application provides a battery cell, a battery, and an electrical device.

[0005] A first aspect of this application provides a battery cell including a housing assembly, wherein the housing assembly includes a pressure relief device and a gas-generating coating; the gas-generating coating is disposed on at least one inner surface of the housing assembly; the gas-generating coating includes a gas-generating agent, which includes an auxiliary gas-generating agent and an organic compound gas-generating agent, wherein the auxiliary gas-generating agent includes an inorganic compound gas-generating agent and / or an oxalate compound.

[0006] In this embodiment, the outer casing of the battery cell is provided with a gas-generating coating comprising an auxiliary gas-generating agent and an organic compound gas-generating agent. This coating generates inert gas when heated. While the auxiliary gas-generating agent, composed of inorganic compound gas-generating agents and / or oxalate compounds, has a lower decomposition temperature, the gas generated during the decomposition of these compounds simultaneously reduces the decomposition activation energy of the organic compound gas-generating agent, thereby lowering its decomposition temperature. Furthermore, the organic compound gas-generating agent produces a greater amount of gas than the inorganic compound gas-generating agent and / or oxalate compounds. Therefore, the combined use of the auxiliary gas-generating agent (inorganic compound gas-generating agent and / or oxalate compounds) and the organic compound gas-generating agent allows the gas-generating coating to generate more inert gas at a lower initial gas generation temperature. This allows the internal pressure of the battery cell to reach the conditions for a braking and pressure relief device at a lower internal temperature, thereby reducing the risk of combustion and explosion due to thermal runaway or thermal diffusion in the battery cell. In summary, the battery cell in this application embodiment can brake the pressure relief device at a lower internal temperature in the early stage of abnormal heat generation inside the battery cell, thereby reducing the internal temperature and / or pressure of the battery cell in advance, and thus reducing the risk of thermal runaway of the battery cell.

[0007] In any embodiment, the mass ratio Z of the auxiliary gas-generating agent to the organic compound gas-generating agent satisfies: 1:4≤Z≤3:7.

[0008] In this embodiment, the organic compound gas-generating agent is the main gas-generating agent and is used to generate a large amount of inert gas. The small amount of gas produced by the auxiliary gas-generating agent, which consists of inorganic compound gas-generating agents and / or oxalate compounds, is used to regulate the gas generation temperature and gas generation rate of the organic compound gas-generating agent. Therefore, when the auxiliary gas-generating agent has a smaller mass proportion than the organic compound gas-generating agent, the gas-generating coating containing the above-mentioned gas-generating agent can have a lower gas generation initiation temperature, while also ensuring that the gas generation amount of the gas-generating coating is sufficient to meet the pressure requirements of the braking pressure relief device inside the battery cell.

[0009] In any embodiment, the inorganic compound gas-generating agent comprises at least one of the following: sodium bicarbonate, sodium carbonate, and ammonium sulfate.

[0010] In the embodiments of this application, the gases and / or substances generated by the thermal decomposition of the inorganic compound gas-generating agent can reduce the decomposition activation energy and decomposition temperature of the organic compound gas-generating agent. Furthermore, the gases and / or substances generated by the thermal decomposition of the inorganic compound gas-generating agent can also catalyze the decomposition and gas-generating reaction of the organic compound gas-generating agent, thereby increasing the gas generation rate of the gas-generating coating.

[0011] In any embodiment, the oxalate compound comprises at least one of the following: ammonium hydrogen oxalate or calcium oxalate.

[0012] In the embodiments of this application, the gases and / or substances generated by the thermal decomposition of oxalate compounds can reduce the decomposition activation energy and decomposition temperature of the organic compound gas-generating agent. Furthermore, the gases and / or substances generated by the thermal decomposition of oxalate compounds can also catalyze the decomposition and gas-generating reaction of the organic compound gas-generating agent, thereby increasing the gas generation rate of the gas-generating coating.

[0013] In any embodiment, the organic compound gas-generating agent comprises at least one of the following: an azo compound, a sulfonyl hydrazine compound, or a nitroso compound.

[0014] In the embodiments of this application, an organic compound gas-generating agent is used to generate a large amount of inert gas, thereby braking the pressure relief device on the housing assembly.

[0015] In any embodiment, the mass percentage G of the gas-generating agent in the gas-generating coating satisfies: 95% ≤ G ≤ 98%.

[0016] In the embodiments of this application, the mass ratio of the gas-generating agent in the gas-generating coating can ensure that the gas generation of the gas-generating coating meets the conditions of the braking pressure relief device, while also allowing the gas-generating coating to accommodate other gas-generating catalysts, thereby further improving the gas generation effect of the gas-generating coating.

[0017] In any embodiment, the gas-generating coating further includes at least one of the following: a gas-generating catalyst, a gas-generating aid, and a binder.

[0018] Optionally, the gas-producing catalyst comprises at least one of the following: ZnO, Fe2O3, MgO, CaO.

[0019] Optionally, the gas production booster is Mg3Si4O 10 (OH)2.

[0020] Optionally, the adhesive comprises at least one of the following: polyvinylidene fluoride, polymethyl acrylate, styrene-butadiene rubber, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, polyvinyl alcohol, and polyurethane.

[0021] In any embodiment, the mass percentage C of the gas-generating catalyst in the gas-generating coating satisfies: 0.1% ≤ C ≤ 1%.

[0022] In any embodiment, the mass percentage A of the gas-generating aid in the gas-generating coating satisfies: 0 < A ≤ 2%.

[0023] In any embodiment, the mass percentage B of the binder in the gas-generating coating satisfies: 0.5% ≤ B ≤ 5%.

[0024] In this embodiment, the gas-generating catalyst in the gas-generating coating accelerates the decomposition of the gas-generating agent at high temperatures, thereby facilitating the rapid generation of a large amount of inert gas. Furthermore, when the inorganic compound gas-generating agent in the gas-generating coating reacts with the gas-generating aid Mg3Si4O... 10 When used in conjunction with (OH)2, it can increase the decomposition reaction area of ​​the inorganic compound gas-generating agent, thereby promoting the gas-generating reaction of the inorganic compound gas-generating agent. The binder in the gas-generating coating is used to bond the gas-generating coating to the inner surface of the battery cell's outer casing assembly.

[0025] In any embodiment, the housing assembly further includes: a housing having an opening; a cover plate covering the opening; and a gas-generating coating disposed on the inner surface of the bottom of the housing opposite the cover plate.

[0026] In this embodiment, the gas-generating coating is disposed at the bottom of the housing, thereby increasing the path of the inert gas generated by the gas-generating coating inside the battery cell (or inside the housing assembly). This allows the inert gas generated by the gas-generating coating when heated to pass through more areas inside the battery cell, thereby allowing more heat from the battery cell components to be discharged from the battery cell along with the inert gas through the pressure relief device.

[0027] In any embodiment, the mass m1 of the gas-generating coating and the mass m2 of the battery cell satisfy the following relationship: 0.006 ≤ m1 / m2 ≤ 0.0144.

[0028] In the embodiments of this application, since the design braking conditions of the pressure relief device are related to the mass of the battery cell itself, controlling the ratio of the mass of the gas-generating coating to the mass of the battery cell can ensure that the amount of gas-generating coating applied is sufficient to ensure that the internal pressure of the battery cell reaches the condition for braking the pressure relief device when the target temperature is reached, thereby reducing the risk of combustion and explosion of the battery cell due to thermal runaway or thermal diffusion.

[0029] In any embodiment, the coverage R of the gas-generating coating on at least one inner surface of the housing assembly satisfies: 80% ≤ R ≤ 100%.

[0030] In this embodiment, the gas-generating coating has sufficient coverage on the inner surface of the housing assembly, thereby increasing the surface area of ​​the gas-generating coating, which in turn allows the gas-generating agent in the gas-generating coating to fully carry out the gas-generating reaction, and also helps the gas-generating coating to fully discharge the generated inert gas from the gas-generating coating.

[0031] In any embodiment, the thickness L of the gas-generating coating on at least one inner surface of the housing assembly satisfies: 1 mm ≤ L ≤ 3 mm.

[0032] In the embodiments of this application, the thickness of the gas-generating coating can ensure that the amount of gas-generating coating applied meets the conditions of the braking pressure relief device, while also taking into account the internal space distribution of the battery cell, thereby reducing the risk of thermal runaway of the battery cell while taking into account the performance of the battery cell.

[0033] A second aspect of this application provides a battery, including the battery cell of the first aspect of this application.

[0034] A third aspect of this application provides an electrical device comprising a battery cell of the first aspect of this application and / or a battery of the second aspect of this application. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a housing assembly according to one embodiment of this application.

[0036] Figure 2 This is a schematic diagram of the housing according to one embodiment of this application.

[0037] Figure 3 This is a schematic diagram of the housing according to another embodiment of this application.

[0038] Figure 4 This is a schematic diagram of the housing according to another embodiment of this application.

[0039] Figure 5 This is another schematic diagram of the housing according to yet another embodiment of this application.

[0040] Figure 6 This is a schematic diagram of a battery cell according to one embodiment of this application.

[0041] Figure 7 This is a schematic diagram of a battery module according to one embodiment of this application.

[0042] Figure 8 This is a schematic diagram of a battery according to one embodiment of this application.

[0043] Figure 9 yes Figure 8 An exploded view of a battery according to one embodiment of this application is shown.

[0044] Figure 10 This is a schematic diagram of an electrical device in which a single battery cell is used as a power source according to one embodiment of this application.

[0045] Figure 11 This is another schematic diagram of the housing according to one embodiment of this application.

[0046] Explanation of reference numerals in the attached figures:

[0047] 1 Battery; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Battery cell; 6 Housing assembly; 61 Housing; 611 Shell; 6111 First side wall; 6112 Second side wall; 6113 Third side wall; 612 Cover plate; 62 Pressure relief device; 63 Gas-generating coating; L Thickness; First direction X; Second direction Y; Third direction Z. Detailed Implementation

[0048] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the electrode plates, battery cells, battery modules, batteries, and power-consuming devices of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0049] 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.

[0050] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0051] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0052] 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.

[0053] During the research on the design of battery cells, the applicant discovered that when thermal runaway or thermal diffusion occurs inside the battery cell, the internal temperature of the battery cell rises rapidly, and the internal pressure of the battery cell may also increase rapidly, which may increase the risk of the battery cell burning and exploding.

[0054] In some related technologies, a heat-absorbing foamed coating is placed inside the battery cell to reduce the abnormal temperature rise rate inside the battery cell. However, while the foamed coating is designed to prevent thermal runaway or thermal diffusion within the battery cell, if abnormal heat generation occurs in the early stages inside the battery cell—that is, when the temperature inside the battery cell is lower than the conditions that would trigger thermal runaway—the foamed coating cannot reduce the temperature and / or pressure inside the battery cell in advance, thus failing to effectively reduce the risk of thermal runaway.

[0055] In view of this, embodiments of this application provide a battery cell including a casing assembly, wherein the casing assembly includes: a pressure relief device; a gas-generating coating disposed on at least one inner surface of the casing assembly; wherein the gas-generating coating comprises a gas-generating agent, including inorganic compound gas-generating agents and organic compound gas-generating agents; wherein the gas-generating coating generates gas upon heating to brake the pressure relief device. Thus, when abnormal heat generation begins inside the battery cell, the pressure relief device of the battery cell can brake at a lower internal temperature, thereby reducing the internal temperature and / or pressure of the battery cell in advance, and thus reducing the risk of thermal runaway of the battery cell.

[0056] [Battery cell]

[0057] In one embodiment of this application, a battery cell 5 is provided. The battery cell 5 includes a housing assembly 6.

[0058] like Figures 1 to 5 As shown, the housing assembly 6 includes a housing 61, a pressure relief device 62, and a gas-generating coating 63. The pressure relief device 62 is disposed on the housing 61. The gas-generating coating 63 is disposed on at least one inner surface of the housing 61. The gas-generating coating 63 contains a gas-generating agent, which includes an auxiliary gas-generating agent and an organic compound gas-generating agent. The auxiliary gas-generating agent includes an inorganic compound gas-generating agent and / or an oxalate compound.

[0059] Specifically, the gas-generating coating 63, containing auxiliary gas-generating agents and organic compound gas-generating agents, generates inert gas when heated. The amount of gas generated by the gas-generating coating 63 can force the pressure relief device 62 inside the housing assembly 6 to brake. In other words, the gas-generating coating 63 can generate gas when heated to brake the pressure relief device 62.

[0060] As an example, the gas-generating coating 63 can be disposed on one inner surface of the housing 61, or it can be disposed on two or more inner surfaces of the housing 61 simultaneously.

[0061] The pressure relief device 62 is actuated to release internal pressure or temperature when the internal pressure or temperature of the housing assembly 6 reaches a threshold. When the internal pressure or temperature of the housing assembly 6 reaches a predetermined threshold, the pressure relief device 62 actuates or a weak structure provided in the pressure relief device 62 is broken, thereby forming an opening or channel for the release of internal pressure or temperature. The threshold design varies depending on design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator housed in the housing assembly 6.

[0062] The pressure relief device 62 provided on the housing assembly 6 can be any of the possible pressure relief devices 62. For example, the pressure relief device 62 can be a temperature-sensitive pressure relief mechanism, which is configured to melt when the internal temperature of the housing assembly 6 with the pressure relief device 62 reaches a threshold; and / or, the pressure relief device 62 can be a pressure-sensitive pressure relief mechanism, which is configured to rupture when the internal air pressure of the housing assembly 6 with the pressure relief device 62 reaches a threshold.

[0063] In this embodiment, the outer casing of the battery cell is provided with a gas-generating coating comprising an auxiliary gas-generating agent and an organic compound gas-generating agent. This coating generates inert gas when heated. While the auxiliary gas-generating agent, composed of inorganic compound gas-generating agents and / or oxalate compounds, has a lower decomposition temperature, the gas generated during the decomposition of these compounds simultaneously reduces the decomposition activation energy of the organic compound gas-generating agent, thereby lowering its decomposition temperature. Furthermore, the organic compound gas-generating agent produces a greater amount of gas than the inorganic compound gas-generating agent and / or oxalate compounds. Therefore, the combined use of the auxiliary gas-generating agent (inorganic compound gas-generating agent and / or oxalate compounds) and the organic compound gas-generating agent allows the gas-generating coating to generate more inert gas at a lower initial gas generation temperature. This allows the internal pressure of the battery cell to reach the conditions for a braking and pressure relief device at a lower internal temperature, thereby reducing the risk of combustion and explosion due to thermal runaway or thermal diffusion in the battery cell. In summary, the battery cell in this application embodiment can brake the pressure relief device at a lower internal temperature in the early stage of abnormal heat generation inside the battery cell, thereby reducing the internal temperature and / or pressure of the battery cell in advance, and thus reducing the risk of thermal runaway of the battery cell.

[0064] In some embodiments, the mass ratio Z of the auxiliary gas-generating agent to the organic compound gas-generating agent satisfies: 1:4 ≤ Z ≤ 3:7.

[0065] Z can be 1:4, 4:15, 3:7 or any value within the above range, and this application does not limit it.

[0066] In this embodiment, the organic compound gas-generating agent is the main gas-generating agent and is used to generate a large amount of inert gas. The small amount of gas produced by the auxiliary gas-generating agent, which consists of inorganic compound gas-generating agents and / or oxalate compounds, is used to regulate the gas generation temperature and gas generation rate of the organic compound gas-generating agent. Therefore, when the auxiliary gas-generating agent has a smaller mass proportion than the organic compound gas-generating agent, the gas-generating coating containing the above-mentioned gas-generating agent can have a lower gas generation initiation temperature, while also ensuring that the gas generation amount of the gas-generating coating is sufficient to meet the pressure requirements of the braking pressure relief device inside the battery cell.

[0067] In some embodiments, the housing 61 includes a housing 611 and a cover 612.

[0068] like Figure 1 and Figure 2 As shown, the housing 611 has an opening, and a cover plate 612 covers the opening of the housing 611. The housing 611 includes two first sidewalls 6111 that are parallel to each other and perpendicular to a first direction X, two second sidewalls 6112 that are parallel to each other and perpendicular to a second direction Y, and a third sidewall 6113 that is perpendicular to a third direction Z. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0069] It is understandable that the third sidewall 6113 can also be referred to as the bottom of the shell 611, and the third sidewall 6113 can be opposite to the cover plate 612.

[0070] The housing 611 can be a hollow structure with openings at one or more ends. For example, if the housing 611 is a hollow structure with an opening at one end, a cover plate 612 can be correspondingly provided; if the housing 611 is a hollow structure with openings at opposite ends (in other words, without the aforementioned third sidewall 6113), two cover plates 612 can be provided, with the two cover plates 212 respectively covering the openings at both ends of the housing 211. Therefore, it can be understood that the pressure relief device 62 in this embodiment can be provided on one cover plate 612 or on two cover plates 612. In addition, this embodiment mainly takes the housing 611 as a hollow structure with an opening at one end as an example.

[0071] Specifically, the gas-generating coating 63 in this embodiment can be disposed on one inner surface of the housing 611, on one inner surface of the opening of the cover plate 612 facing the housing 611, or simultaneously on two or more inner surfaces of the housing 611 and / or the cover plate 612.

[0072] As an example, such as Figure 3As shown, the gas-generating coating 63 can be simultaneously disposed on both first sidewalls 6111 and both second sidewalls 6112 of the housing 611. It should be noted that the gas-generating coating 63 can also be disposed on only one or both first sidewalls 6111 of the housing 611, or only one or both second sidewalls 6112 of the housing 611, or even on one first sidewall 6111 and one second sidewall 6112 of the housing 611. Furthermore, Figure 3 The above embodiments are merely illustrative examples and are not intended to limit the scope of this application.

[0073] In the embodiments of this application, the gas-generating coating can be disposed on any one or more inner surfaces of the casing assembly of the battery cell, thereby increasing the surface area and / or mass of the gas-generating coating, so that the gas-generating agent in the gas-generating coating can fully carry out the gas-generating reaction.

[0074] Optionally, such as Figure 4 and Figure 5 As shown, the gas-generating coating 63 can also be disposed on the third side wall 6113 of the housing 611 (also referred to as the bottom of the housing 611).

[0075] In one possible scenario, the gas-generating coating 63 disposed on the third sidewall 6113 of the housing 611 is opposite to the cover plate 612.

[0076] In this embodiment, the gas-generating coating is disposed at the bottom of the housing, thereby increasing the path of the inert gas generated by the gas-generating coating inside the battery cell (or inside the housing assembly). This allows the inert gas generated by the gas-generating coating when heated to pass through more areas inside the battery cell, thereby allowing more heat from the battery cell components to be discharged from the battery cell along with the inert gas through the pressure relief device.

[0077] In some embodiments, the mass m1 of the gas-generating coating 63 and the mass m2 of the battery cell 5 satisfy the following condition: 0.006 ≤ m1 / m2 ≤ 0.0144.

[0078] It is understood that the mass of the battery cell 5 includes the mass of the housing assembly 6 and other battery cell components (e.g., positive and negative electrode plates) deployed inside the battery cell 5.

[0079] m1 / m2 can be 0.006, 0.008, 0.01, 0.012, 0.014, 0.0144 or any ratio within the above range, and this application does not limit it.

[0080] In the embodiments of this application, since the design braking conditions of the pressure relief device are related to the mass of the battery cell itself, controlling the ratio of the mass of the gas-generating coating to the mass of the battery cell can ensure that the amount of gas-generating coating applied is sufficient to ensure that the internal pressure of the battery cell reaches the condition for braking the pressure relief device when the target temperature is reached, thereby reducing the risk of combustion and explosion of the battery cell due to thermal runaway or thermal diffusion.

[0081] In some embodiments, the coverage R of the gas-generating coating 63 on at least one inner surface of the housing assembly 6 satisfies: 80% ≤ R ≤ 100%.

[0082] R can be 80%, 85%, 90%, 95%, 100% or any value within the above range, and is not limited herein.

[0083] Specifically, the coverage of the gas-generating coating 63 on at least one inner surface of the housing assembly 6 may be the coverage on one inner surface, or the same coverage on two or more inner surfaces, or different coverage on two or more inner surfaces within the aforementioned range.

[0084] In this embodiment, the gas-generating coating has sufficient coverage on the inner surface of the housing assembly, thereby increasing the surface area of ​​the gas-generating coating, which in turn allows the gas-generating agent in the gas-generating coating to fully carry out the gas-generating reaction, and also helps the gas-generating coating to fully discharge the generated inert gas from the gas-generating coating.

[0085] In some embodiments, the thickness L of the gas-generating coating 63 on at least one inner surface of the housing assembly 6 satisfies: 1 mm ≤ L ≤ 3 mm.

[0086] L can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm or any value within the above range, and this application does not limit it.

[0087] Specifically, such as Figure 3 As shown, the thickness L of the gas-generating coating 63 disposed on the first sidewall 6111 in the first direction X satisfies the above-mentioned range, and the thickness L of the gas-generating coating 63 disposed on the second sidewall 6112 in the second direction Y also satisfies the above-mentioned range. Alternatively, as... Figure 5 As shown, the thickness L of the gas-generating coating 63 disposed on the third sidewall 6113 in the third direction Z satisfies the above-mentioned range.

[0088] In the embodiments of this application, the thickness of the gas-generating coating can ensure that the amount of gas-generating coating applied meets the conditions of the braking pressure relief device, while also taking into account the internal space distribution of the battery cell, thereby reducing the risk of thermal runaway of the battery cell while taking into account the performance of the battery cell.

[0089] In some embodiments, the auxiliary gas-generating agent may be an inorganic compound gas-generating agent, which includes at least one of the following: sodium bicarbonate, sodium carbonate, and ammonium sulfate.

[0090] In one possible scenario, when the inorganic gas-generating agent is sodium bicarbonate and / or sodium carbonate, the carbon dioxide and water produced during the thermal decomposition of the inorganic gas-generating agent can lower the activation energy of the organic gas-generating agent, thereby reducing its decomposition temperature. Furthermore, when the inorganic gas-generating agent is sodium bicarbonate, its weakly basic nature can interact with the acidic products produced during the decomposition of the organic gas-generating agent, altering the decomposition reaction pathway and further reducing its decomposition temperature.

[0091] Another possible scenario is that when the inorganic gas-generating agent is ammonium sulfate, the ammonia gas produced when the inorganic gas-generating agent decomposes under heat can provide an alkaline environment for the decomposition process of the organic gas-generating agent. This causes the acidic products produced during the decomposition of the organic gas-generating agent to interact with the base, thereby changing the decomposition reaction pathway of the organic gas-generating agent and ultimately lowering the decomposition temperature of the organic gas-generating agent.

[0092] In the embodiments of this application, the gases and / or substances generated by the thermal decomposition of the inorganic compound gas-generating agent can reduce the decomposition activation energy and decomposition temperature of the organic compound gas-generating agent. Furthermore, the gases and / or substances generated by the thermal decomposition of the inorganic compound gas-generating agent can also catalyze the decomposition and gas-generating reaction of the organic compound gas-generating agent, thereby increasing the gas generation rate of the gas-generating coating.

[0093] In some embodiments, the auxiliary gas-generating agent may also be an oxalate compound, which may be ammonium hydrogen oxalate and / or calcium oxalate.

[0094] In one possible scenario, when the auxiliary gas-generating agent in the gas-generating coating 63 is ammonium oxalate, the ammonia and water produced when ammonium oxalate decomposes upon heating can provide an alkaline environment for the decomposition process of the organic compound gas-generating agent. This allows the acidic products produced during the decomposition of the organic compound gas-generating agent to undergo acid-base interactions, thereby altering the decomposition reaction pathway of the organic compound gas-generating agent and ultimately lowering its decomposition temperature.

[0095] In another possible scenario, when the auxiliary gas-generating agent in the gas-generating coating 63 is calcium oxalate, the ammonia gas produced when calcium oxalate decomposes upon heating can provide an alkaline environment for the decomposition process of the organic compound gas-generating agent. This allows the acidic products produced during the decomposition of the organic compound gas-generating agent to undergo acid-base interactions, thereby altering the decomposition reaction pathway of the organic compound gas-generating agent and ultimately lowering its decomposition temperature.

[0096] In some embodiments, the organic compound gas-generating agent comprises at least one of the following: an azo compound, a sulfonyl hydrazine compound, or a nitroso compound.

[0097] In the embodiments of this application, an organic compound gas-generating agent is used to generate a large amount of inert gas, thereby braking the pressure relief device on the housing assembly.

[0098] In some embodiments, the mass percentage G of the gas-generating agent in the gas-generating coating 63 satisfies: 95% ≤ G ≤ 98%.

[0099] G can be 95%, 96%, 97%, 98% or any value within the above range, and this application does not limit it.

[0100] In this application, the mass ratio of the gas-generating agent in the gas-generating coating can ensure that the gas generation of the gas-generating coating meets the conditions of the brake pressure relief device, while also allowing the gas-generating coating to accommodate other gas-generating catalysts, thereby further improving the gas generation effect of the gas-generating coating.

[0101] In some embodiments, the gas-generating coating 63 further includes at least one of the following: a gas-generating catalyst, a gas-generating aid, and a binder.

[0102] In some embodiments, the gas-generating catalyst comprises at least one of the following: ZnO, Fe2O3, MgO, and CaO. Optionally, the mass percentage C of the gas-generating catalyst in the gas-generating coating 63 satisfies: 0.1% ≤ C ≤ 1%.

[0103] C can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or any value within the above range, and is not limited herein.

[0104] In the embodiments of this application, the gas-generating catalyst in the gas-generating coating can accelerate the decomposition of the gas-generating agent at high temperature, thereby helping to quickly generate a large amount of inert gas.

[0105] In some embodiments, the gas-generating booster is Mg3Si4O 10 (OH)2. Optionally, the mass percentage A of the gas-generating aid in the gas-generating coating 63 satisfies: 0 < A ≤ 2%.

[0106] A can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or any value within the above range, and is not limited herein.

[0107] In the embodiments of this application, when the inorganic compound gas-generating agent in the gas-generating coating reacts with the gas-generating aid Mg3Si4O 10 When (OH)2 is used in combination, it can increase the decomposition reaction area of ​​inorganic compound gas-generating agents, thereby promoting the gas-generating reaction of inorganic compound gas-generating agents.

[0108] In some embodiments, the binder comprises at least one of the following: polyvinylidene fluoride, polymethyl acrylate, styrene-butadiene rubber, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, polyvinyl alcohol, and polyurethane. Optionally, the mass percentage B of the binder in the gas-generating coating 63 satisfies: 0.5% ≤ B ≤ 5%.

[0109] B can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or any value within the above range, and is not limited herein.

[0110] In the embodiments of this application, the binder in the gas-generating coating is used to bond the gas-generating coating to the inner surface of the casing assembly of the battery cell.

[0111] In addition, the battery cell, battery module, battery and power device of this application will be described below with appropriate reference to the accompanying drawings.

[0112] Typically, a battery cell includes a positive electrode, a negative electrode, an electrolyte, and a separator. During charging and discharging, active ions move back and forth between the positive and negative electrodes, inserting and releasing. 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.

[0113] [Positive electrode plate]

[0114] In some embodiments, 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 substrate and a metal layer formed on at least one surface of the polymer 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 substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0115] In some embodiments, the positive electrode active material layer may employ positive electrode active materials known in the art for use in batteries. 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 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 NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure 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.

[0116] In some embodiments, 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.

[0117] In some embodiments, 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.

[0118] In some embodiments, the positive electrode sheet can be prepared by dispersing the positive active material, conductive agent, binder 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 current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0119] [Negative electrode plate]

[0120] The negative electrode includes a negative current collector and a negative electrode film layer disposed on the negative current collector.

[0121] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. The negative electrode current collector may be copper foil. The composite negative electrode 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 substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0122] In some embodiments, the negative electrode film layer includes a negative electrode active material. 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 one or more of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based material may be selected from one or more of elemental silicon, silicon-oxygen compounds, silicon-carbon compounds, silicon-nitrogen compounds, and silicon alloys. The tin-based material may be selected from one or more of elemental tin, tin oxide compounds, and tin alloys. 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.

[0123] In some embodiments, the negative electrode film layer may optionally include a binder. As an example, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0124] In some embodiments, the negative electrode film may optionally include a conductive agent. The conductive agent may be selected from one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0125] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0126] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode film, 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 then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0127] [Electrolytes]

[0128] The electrolyte acts as a conductor of ions between the positive and negative electrodes. 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 entirely solid.

[0129] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0130] In some embodiments, the electrolyte salt may be selected from 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, and lithium tetrafluorooxalate phosphate.

[0131] In some embodiments, the solvent may be selected from at least one of 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, methyl ethyl sulfone, and diethyl sulfone.

[0132] In some embodiments, 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.

[0133] [Isolation membrane]

[0134] In some embodiments, the battery cell also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0135] In some embodiments, the material of the separator can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can 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 can be the same or different, without particular limitation.

[0136] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0137] In some embodiments, the battery cell may include an outer packaging. This outer packaging can be used to encapsulate the electrode assembly and electrolyte described above.

[0138] In some embodiments, the outer packaging of the battery cell can be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the battery cell can also be a flexible package, such as a pouch. The material of the flexible package can be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0139] This application does not impose any particular limitation on the shape of the battery cell; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 6 The battery cell 5 is used as an example. Battery cell 5 may include the aforementioned housing assembly 6. The positive electrode, negative electrode, and separator may be formed into an electrode assembly via a winding or stacking process. The electrode assembly is encapsulated within the housing assembly 6. Electrolyte is immersed in the electrode assembly. The battery cell 5 may contain one or more electrode assemblies, which can be selected by those skilled in the art according to specific practical needs.

[0140] In some implementations, individual battery cells can be assembled into a battery module. The number of individual battery cells contained in a battery module can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery module.

[0141] Figure 7 This is battery module 4, used as an example. (See reference...) Figure 7 In battery module 4, multiple battery cells 5 can be arranged sequentially along the length of battery module 4. Of course, they can also be arranged in any other manner. Furthermore, these multiple battery cells 5 can be fixed in place using fasteners.

[0142] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple battery cells 5 are received.

[0143] In some embodiments, the battery modules described above can also be assembled into a battery. The number of battery modules contained in the battery can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery.

[0144] Figure 8 and Figure 9 This is battery 1 as an example. (See reference...) Figure 8 and Figure 9 The battery 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3, with the upper body 2 covering the lower body 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0145] In addition, this application also provides an electrical device, which includes at least one of the battery cell, battery module, or battery provided in this application. The battery cell, battery module, or battery can be used as a power source for the electrical device, or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0146] As the electrical device, a single battery cell, a battery module, or a battery can be selected according to its usage requirements.

[0147] Figure 10 This is an example of an electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of individual battery cells, batteries or battery modules can be used.

[0148] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use a single battery cell as their power source.

[0149] [Example]

[0150] 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.

[0151] Example 1

[0152] (1) Preparation of positive electrode sheet

[0153] I. Preparation of positive electrode slurry

[0154] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 O2, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) are dissolved in solvent N-methylpyrrolidone (NMP) at a weight ratio of 96.5:1.5:2 and thoroughly mixed to obtain the positive electrode slurry.

[0155] II. Preparation of Positive Electrode Sheet

[0156] The prepared positive electrode slurry was uniformly coated onto an aluminum foil current collector and dried at 110–150°C. After cold pressing and slitting, the positive electrode sheet was obtained.

[0157] (2) Preparation of negative electrode sheet

[0158] The negative electrode active material graphite, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), and thickener sodium carboxymethyl cellulose (CMC-Na) are dissolved in deionized water at a mass ratio of 96:1:1:2 and thoroughly mixed to prepare a negative electrode slurry. The negative electrode slurry is coated onto the negative electrode current collector copper foil, and then dried, cold-pressed, and slit to obtain the negative electrode sheet.

[0159] (3) Separating membrane

[0160] Polyethylene film was selected as the separator.

[0161] (4) Electrolyte

[0162] Ethyl carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1, and then LiPF6 was uniformly dissolved in the above solution at a concentration of 1 mol / L to obtain the electrolyte.

[0163] (5) Preparation of battery cells

[0164] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a barrier between the positive and negative electrodes. The cells are then wound to obtain a bare cell. Tabs are welded onto the bare cell, and the cell is placed in an aluminum shell. It is then baked at 80°C to remove water, followed by the injection of electrolyte and sealing. The cells then undergo a series of processes including settling, hot and cold pressing, formation, shaping, and capacity testing to produce a single battery cell.

[0165] The inner surface of the bottom of the aforementioned aluminum shell is coated with a 1mm thick gas-generating coating, which constitutes 100% of the surface. This coating comprises 20% sodium bicarbonate (an auxiliary gas-generating agent), 75% azodicarbonamide (an organic compound gas-generating agent), 1% zinc oxide (a catalyst), and 2% Mg3Si4O3 (a gas-generating aid). 10 (OH)2 and 2% by mass of polyvinylidene fluoride binder. The mass ratio of the gas-generating coating to the mass of the prepared battery cell is 0.006.

[0166] Example 2

[0167] The difference between Example 2 and Example 1 is that the thickness of the gas-generating coating is different, and the ratio of the mass of the gas-generating coating to the mass of the battery cell is different.

[0168] Example 3

[0169] The difference between Example 3 and Example 1 is that the thickness of the gas-generating coating is different, the ratio of the mass of the gas-generating coating to the mass of the battery cell is different, and the coating ratio of the gas-generating coating on the bottom of the casing is different.

[0170] Examples 4-5

[0171] The differences between Examples 4-5 and Example 1 are: the inorganic compound components of the auxiliary gas-generating agent are different, the mass ratio of the auxiliary gas-generating agent in the gas-generating coating is different, the components of the organic compound gas-generating agent are different, and the mass ratio of the organic compound gas-generating agent in the gas-generating coating is different.

[0172] Examples 6-7

[0173] The difference between Examples 6-7 and Example 1 is that the auxiliary gas-generating agent is composed of oxalate compounds.

[0174] Comparative Example 1

[0175] The difference between Comparative Example 1 and Example 1 is that no gas-generating coating is provided on the inner surface of the bottom of the outer shell.

[0176] The specific parameters of the battery cells in Examples 1-7 and Comparative Example 1 are shown in Table 1 below.

[0177] Table 1: Specific parameters of Examples 1-7 and Comparative Example 1

[0178] In addition, the battery cells in Examples 1-7 and Comparative Example 1 were subjected to performance tests. The test results are shown in Table 2 below.

[0179] Table 2: Performance test results of Examples 1-7 and Comparative Example 1

[0180] [Testing methods for individual battery cell parameters]

[0181] The battery cells being tested can be either freshly assembled and unformed, or battery cells removed from electrical devices (such as vehicles).

[0182] (1) Test of the braking condition of the pressure relief device when a single battery cell is overcharged

[0183] Under a test environment of 25°C, the prepared battery cells were charged to 100% SOC at a constant current of 1 / 3C. Then, the battery cells were overcharged at a constant current of 1 / 3C. When the pressure relief device of the battery cell was deactivated, the temperature at the center of the sidewall of the casing assembly was recorded (i.e., the deactivation temperature). When thermal runaway occurred in the battery cell, or 30 minutes after the pressure relief device was deactivated, the highest temperature at the center of the sidewall of the casing assembly was recorded. Specifically, "thermal runaway" refers to a significant temperature rise (i.e., >500°C) at the center of the sidewall of the casing assembly within a short period (i.e., within 10 seconds).

[0184] Specifically, such as Figure 11 As shown, the "center position of the side wall of the housing assembly" can be a point Q on any side wall of the housing assembly (or housing) that is equidistant from the four vertices of that side wall, wherein point Q is located on a plane of any side wall of the housing assembly (or housing) that is away from the interior of the housing assembly.

[0185] (2) Test of the braking condition of the pressure relief device of the battery cell in the hot box

[0186] The prepared battery cells were charged to 100% SOC using a constant current of 1 / 3C. Then, the battery cells were placed in a hot chamber, and the chamber was heated to 60°C at a constant rate and held for 5 hours. Afterward, the hot chamber was heated at a rate of 5°C / min, holding for 30 minutes after each 5°C increase. The temperature inside the hot chamber (i.e., the braking temperature of the pressure relief device) was recorded when the pressure relief device of the battery cell was deactivated. The process was stopped if either of these two conditions occurred: thermal runaway of the battery cell or the hot chamber was held at 200°C for 3 hours. The temperature inside the hot chamber and the highest temperature at the center of the side wall of the outer casing assembly were obtained.

[0187] Referring to Examples 1-5 and Comparative Example 1, the battery cells in Examples 1-5 are equipped with a gas-generating coating comprising an inorganic compound gas-generating agent (also known as an auxiliary gas-generating agent) and an organic compound gas-generating agent. When the battery cell overcharges and heats up, the pressure relief device can be braked at a lower temperature, thereby reducing the risk of thermal runaway. In contrast, the battery cell in Comparative Example 1, without a gas-generating coating, requires a higher temperature to brake the pressure relief device when overcharged and heats up, and the battery cell also experiences thermal runaway.

[0188] As shown in Examples 6-7 and Comparative Example 1, when the auxiliary gas-generating agent of the gas-generating coating is oxalate, the pressure relief device can be braked at a lower temperature when the battery cell is overcharged and heated, thereby reducing the risk of thermal runaway of the battery cell.

[0189] 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 battery cell, characterized in that, The device includes a housing assembly, wherein the housing assembly includes a pressure relief device and a gas-generating coating; the gas-generating coating is disposed on at least one inner surface of the housing assembly; the gas-generating coating contains a gas-generating agent, the gas-generating agent including an auxiliary gas-generating agent and an organic compound gas-generating agent, the auxiliary gas-generating agent including an inorganic compound gas-generating agent and / or an oxalate compound.

2. The battery cell according to claim 1, characterized in that, The mass ratio Z of the auxiliary gas-generating agent to the organic compound gas-generating agent satisfies: 1:4 ≤ Z ≤ 3:

7.

3. The battery cell according to claim 1 or 2, characterized in that, The inorganic compound gas-generating agent comprises at least one of the following: sodium bicarbonate, sodium carbonate, and ammonium sulfate.

4. The battery cell according to any one of claims 1-3, characterized in that, The oxalate compound comprises at least one of the following: ammonium hydrogen oxalate or calcium oxalate.

5. The battery cell according to any one of claims 1-4, characterized in that, The organic compound gas-generating agent comprises at least one of the following: azo compounds, sulfonyl hydrazine compounds, and nitroso compounds.

6. The battery cell according to any one of claims 1-5, characterized in that, The mass percentage G of the gas-generating agent in the gas-generating coating satisfies: 95% ≤ G ≤ 98%.

7. The battery cell according to any one of claims 1-6, characterized in that, The gas-generating coating further includes at least one of the following: a gas-generating catalyst, a gas-generating aid, and a binder.

8. The battery cell according to claim 7, characterized in that, The gas-producing catalyst comprises at least one of the following: ZnO, Fe2O3, MgO, CaO; and / or, The gas-generating booster is Mg3Si4O 10 (OH)2; and / or, The adhesive comprises at least one of the following: polyvinylidene fluoride, polymethyl acrylate, styrene-butadiene rubber, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, polyvinyl alcohol, and polyurethane.

9. The battery cell according to claim 7 or 8, characterized in that, The mass percentage C of the gas-generating catalyst in the gas-generating coating satisfies: 0.1% ≤ C ≤ 1%; and / or, The mass percentage A of the gas-generating aid in the gas-generating coating satisfies: 0 < A ≤ 2%; and / or, The mass percentage B of the binder in the gas-generating coating satisfies: 0.5% ≤ B ≤ 5%.

10. The battery cell according to any one of claims 1-9, characterized in that, The housing assembly also includes: A housing having an opening; A cover plate that closes on the opening; The gas-generating coating is disposed on the inner surface of the bottom of the housing opposite to the cover plate.

11. The battery cell according to any one of claims 1-10, characterized in that, The mass m1 of the gas-generating coating and the mass m2 of the battery cell satisfy the following relationship: 0.006≤m1 / m2≤0.0144.

12. The battery cell according to any one of claims 1-11, characterized in that, The coverage R of the gas-generating coating on at least one inner surface of the housing assembly satisfies: 80% ≤ R ≤ 100%.

13. The battery cell according to any one of claims 1-12, characterized in that, The thickness L of the gas-generating coating on at least one inner surface of the housing assembly satisfies: 1mm ≤ L ≤ 3mm.

14. A battery, characterized in that, Includes the battery cell according to any one of claims 1-13.

15. An electrical appliance, characterized in that, It includes at least one of the following: the battery cell of any one of claims 1-13, and the battery of claim 14.

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