Battery cell, battery device, energy storage device, and electric device

Abstract

A battery cell, a battery device, an energy storage device, and an electric device. The battery comprises a casing, an electrode assembly, and an overcharge protection mechanism. The casing comprises a first wall, the electrode assembly is arranged in the casing, and the overcharge protection mechanism is arranged on the first wall. The electrode assembly comprises a gas-generating agent, and the gas-generating agent comprises at least one of carbonate, oxalate or chloride. The battery cell can effectively improve the reliability of the battery device.

Description

Battery cell, battery device, energy storage device and electric device Cross-reference to Related Applications

[0001] This application claims priority to Chinese Patent Application No. 202410756060.X, filed on June 12, 2024, entitled “Battery cell, battery device, energy storage device and electric device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of battery, in particular, relates to a battery cell, a battery device, an energy storage device and an electric device. BACKGROUND

[0003] Energy saving and emission reduction is the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their energy-saving and environmentally friendly advantages. For electric vehicles, battery technology is an important factor for their development.

[0004] In the development of battery technology, how to improve the reliability of the battery device is a technical problem that needs to be solved in battery technology. SUMMARY

[0005] The present application provides a battery cell, a battery device, an energy storage device and an electric device. The technical solution provided by the present application can effectively improve the reliability of the battery device.

[0006] In a first aspect, the present application provides a battery cell. The battery cell includes a housing, an electrode assembly and an overcharge protection mechanism. The housing has a first wall, the electrode assembly is arranged in the housing, and the overcharge protection mechanism is arranged on the first wall. The electrode assembly includes a gas generating agent, and the gas generating agent includes at least one of a carbonate salt, an oxalate salt or a chloride salt.

[0007] In the above-mentioned solution, by arranging the gas generating agent in the electrode assembly, when the voltage of the battery cell increases to a certain extent due to overcharge or other misuse conditions, the gas generating agent will decompose to generate gas before the main electrochemical substances of the battery cell, so that the internal pressure of the battery cell increases in advance to trigger the overcharge protection mechanism (safety short circuit device (SSD) or current interrupt device (CID)) in advance to achieve overcharge protection, thereby reducing the risk of thermal runaway of the battery cell due to the decomposition of the main electrochemical substances of the battery cell to generate a large amount of heat, and further improving the reliability of the battery.

[0008] According to some embodiments of the present application, the gas generating agent includes at least one of a carbonate salt of lithium, sodium, potassium, magnesium, calcium or aluminum.

[0009] In the above solution, by including at least one of carbonates of lithium, sodium, potassium, magnesium, calcium or aluminum in the gas generating agent, the gas generated by the decomposition of the gas generating agent includes carbon dioxide, which can trigger the overcharge protection mechanism in advance, and improve the anti-explosion performance of the battery monomer, thereby effectively improving the reliability of the battery.

[0010] According to some embodiments of the present application, the gas generating agent includes at least one of lithium carbonate, lithium oxalate or lithium chloride.

[0011] In the above solution, by including at least one of lithium carbonate, lithium oxalate or lithium chloride in the gas generating agent, the gas generating agent can be decomposed at a suitable voltage, thereby balancing the normal charging and discharging of the battery monomer and the timeliness of the overcharge protection, and thereby improving the reliability of the battery monomer.

[0012] According to some embodiments of the present application, the electrode assembly includes a pole piece, and the gas generating agent is disposed on the pole piece.

[0013] In the above solution, by disposing the gas generating agent on the pole piece, on the one hand, the process of disposing the gas generating agent on the pole piece is simple, which can effectively reduce the impact of the gas generating agent on the manufacturing efficiency of the battery monomer, and on the other hand, the gas generating agent can be effectively provided with an electric decomposition condition, and the gas can be effectively decomposed to trigger the overcharge protection mechanism in advance, thereby realizing the timeliness of the overcharge protection, and thereby improving the reliability of the battery monomer.

[0014] According to some embodiments of the present application, the pole piece includes a positive pole piece, and the gas generating agent is disposed on the positive pole piece.

[0015] According to some embodiments of the present application, the positive pole piece includes a positive current collector and a positive active material layer coated on the surface of the positive current collector, and the gas generating agent is disposed on the positive active material layer.

[0016] In the above solution, by disposing the gas generating agent on the positive active material layer, the impact of the gas generating agent on the charging and discharging performance of the battery monomer can be effectively reduced, the charging and discharging performance of the battery monomer and the timeliness of the overcharge protection can be balanced, and thereby the reliability of the battery can be effectively improved.

[0017] According to some embodiments of the present application, the positive active material layer includes a positive active material, a binder, a conductive agent and a gas generating agent.

[0018] In the above solution, the positive active material layer is mixed with the gas generating agent, which can make the gas generating agent decompose to generate gas before the main electrochemical substances of the battery monomer when the voltage of the battery monomer increases to a certain extent due to misuse such as overcharge, so that the internal pressure of the battery monomer increases in advance to trigger the overcharge protection mechanism to realize overcharge protection, thereby improving the reliability of the battery.

[0019] According to some embodiments of the present application, the mass percentage of the gas generating agent in the positive electrode active material layer is 0.1% to 10%.

[0020] In the above scheme, by setting the mass percentage of the gas generating agent in the positive electrode active material layer to 0.1% to 10%, the charge-discharge performance of the battery monomer and the timeliness of the overcharge protection can be considered.

[0021] According to some embodiments of the present application, the mass percentage of the gas generating agent in the positive electrode active material layer is 0.5% to 5.0%.

[0022] In the above scheme, by setting the mass percentage of the gas generating agent in the positive electrode active material layer to 0.5% to 5.0%, the charge-discharge performance of the battery monomer and the timeliness of the overcharge protection can be further considered.

[0023] According to some embodiments of the present application, the positive electrode sheet includes a positive electrode current collector, a gas generating layer, and a positive electrode active material layer, the positive electrode active material layer is arranged between the positive electrode current collector and the gas generating layer, and the gas generating layer includes a gas generating agent, a binder, and a conductive agent.

[0024] In the above scheme, on the one hand, the process is simple, the gas generating layer is easy to coat, and the timeliness of the overcharge protection is beneficial to improve the reliability of the battery device; on the other hand, compared with the current scheme of adding an activator to stimulate the gas generating agent, the battery monomer provided by some embodiments of the present application can make the gas generating agent decompose to generate gas to trigger the overcharge protection mechanism when the voltage reaches a certain value, thereby facilitating the control of the mass and volume energy density of the battery monomer, and making the mass and volume energy density of the battery device high.

[0025] According to some embodiments of the present application, the positive electrode sheet includes a positive electrode current collector, a gas generating layer, and a positive electrode active material layer, the gas generating layer is arranged between the positive electrode current collector and the positive electrode active material layer, and the gas generating layer includes a gas generating agent, a binder, and a conductive agent.

[0026] In the above scheme, the gas generating layer can be arranged on the positive electrode current collector before the coating process, on the one hand, the process is simple, the gas generating layer is easy to coat, and the timeliness of the overcharge protection is beneficial to improve the reliability of the battery device; on the other hand, compared with the current scheme of adding an activator to stimulate the gas generating agent, the battery monomer provided by some embodiments of the present application can make the gas generating agent decompose to generate gas to trigger the overcharge protection mechanism when the voltage reaches a certain value, thereby facilitating the control of the mass and volume energy density of the battery monomer, and making the mass and volume energy density of the battery device high.

[0027] According to some embodiments of the present application, the battery monomer further includes a first electrode terminal, and the first wall is arranged in insulation. The overcharge protection mechanism includes a first deformation member, the first deformation member is electrically connected with the first wall, and the first deformation member is configured to be deformable to be electrically connected with the first electrode terminal.

[0028] In the above scheme, by arranging the first deformation member, when the internal pressure of the battery monomer reaches a certain degree, for example, the first threshold value, the first deformation member is deformed to be electrically connected with the first electrode terminal, so that the positive and negative electrodes of the battery monomer are short-circuited to cause internal short circuit, so that the electrical connection member in the battery monomer is melted due to the large current generated by the short circuit, so as to cut off the charging and discharging circuit of the battery monomer, thereby playing the role of overcharge protection, and reducing the risk of thermal runaway of the battery monomer, thereby making the battery device have higher reliability.

[0029] According to some embodiments of the present application, the first electrode terminal comprises a first conductive member and a first pole, the first conductive member and the first pole are connected with each other, the first conductive member is arranged outside the first wall and insulated from the first wall, and the first pole is electrically connected with the electrode assembly. The first deformation member is configured to be deformed to contact the first conductive member to electrically connect the first pole with the first wall.

[0030] In the above scheme, by arranging the first conductive member outside the first wall, on the one hand, it is convenient to connect with the external bus member, and on the other hand, it is beneficial to the deformation of the first deformation member towards the outside under the action of the internal pressure to effectively conduct the first electrode terminal and the first wall, thereby realizing overcharge protection and improving the reliability of the battery device.

[0031] According to some embodiments of the present application, the battery monomer further comprises a first insulating member, at least part of the first insulating member is arranged between the first conductive member and the first wall.

[0032] In the above scheme, by arranging the first insulating member between the first wall and the first conductive member, the first wall and the first conductive member can be effectively insulated and isolated, the risk of internal short circuit of the battery monomer caused by short circuit between the first wall and the first conductive member is reduced, and the reliability of the battery device is high. Especially in the energy storage device with high working voltage, by arranging the first insulating member between the first wall and the first conductive member, the risk of thermal runaway of the energy storage device caused by the high-voltage electricity of the shell due to the out-of-control of the remaining battery monomers in the battery device conducting the first wall and the first conductive member to cause internal short circuit of the battery monomer is effectively reduced.

[0033] According to some embodiments of the present application, the resistance value of the first insulating member is greater than or equal to 200 megaohms.

[0034] In the above scheme, by setting the resistance value of the first insulating member to be greater than or equal to 200 megaohms, the insulation and high-voltage resistance between the first conductive member and the first wall can be effectively improved, the insulation and pressure demand of the energy storage device can be effectively adapted, the risk of internal short circuit of the battery monomer caused by the external voltage breaking through the first insulating member to conduct the first wall and the first conductive member is reduced, and the energy storage device has higher reliability.

[0035] According to some embodiments of the present application, the first wall has a first electrode lead-out hole, and the first pole passes through the first electrode lead-out hole; the battery monomer further comprises a second insulating member, at least part of the second insulating member is arranged between the hole wall of the first electrode lead-out hole and the first pole.

[0036] In the above scheme, by arranging the second insulating member between the hole wall of the first electrode lead-out hole and the first pole, the first wall and the first pole can be effectively insulated and isolated, the risk of internal short circuit of the battery monomer caused by short circuit between the first wall and the first pole is reduced, and the reliability of the battery device is high.

[0037] According to some embodiments of the present application, the outer circumferential surface of the first pole is formed with a first flange, and part of the second insulating member is located between the first flange and the inner side surface of the first wall in the thickness direction of the first wall.

[0038] In the above scheme, by arranging part of the second insulating member between the first flange and the inner side surface of the first wall, on the one hand, the first pole and the first wall can be effectively insulated and isolated, and on the other hand, the movement of the first pole in the thickness direction of the first wall can be limited, so that the first electrode terminal is stably arranged on the first wall.

[0039] According to some embodiments of the present application, the resistance value of the second insulating member is greater than or equal to 200 megaohms.

[0040] In the above scheme, by setting the resistance value of the second insulating member to be greater than or equal to 200 megaohms, the insulation and high-voltage resistance between the first pole and the first wall can be effectively improved, the insulation and pressure resistance demand of the energy storage device can be effectively adapted, the risk of internal short circuit of the battery monomer caused by the external voltage breaking through the second insulating member to conduct the first wall and the first pole is reduced, and the energy storage device has high reliability.

[0041] According to some embodiments of the present application, the surface of the first conductive member facing the first wall is provided with a first protrusion, and the first protrusion is used to contact the first deformation member.

[0042] In the above scheme, by arranging the first protrusion on the side of the first conductive member facing the first wall, the travel of the first deformation member after deformation and contacting the first conductive member can be shortened, the sensitivity and timeliness of overcharge protection can be effectively improved, and the reliability of the battery device is improved.

[0043] According to some embodiments of the present application, the first deformation member comprises a first contact part, a first deformation part and a first connecting part, the first deformation part is arranged on the outer circumferential surface of the first contact part, the first connecting part is arranged on the end of the first deformation part away from the first contact part, the first connecting part is connected with the first wall, and the first deformation part is configured to be deformable to make the first contact part contact the first conductive member.

[0044] In the above scheme, the first deformation member is simple in structure and easy to manufacture. The first contact portion is caused to contact the first conductive member by stress deformation of the first deformation portion, so that the overcharge protection function can be effectively achieved, and the reliability of the battery device is high.

[0045] According to some embodiments of the present application, the maximum thickness of the first deformation portion is less than the maximum thickness of the first connecting portion, and the maximum thickness of the first deformation portion is less than the maximum thickness of the first contact portion.

[0046] In the above scheme, by setting the thickness of the first deformation portion to be small, the first contact portion can be caused to contact the first conductive member due to deformation of the first deformation portion when the internal pressure of the battery cell reaches a certain degree, so that the overcharge protection function can be effectively achieved in time, and the reliability of the battery device is improved.

[0047] According to some embodiments of the present application, the battery cell further comprises a second electrode terminal and a second deformation member. The second electrode terminal is insulated from the first wall. The second deformation member is electrically connected to the first wall, and is configured to be deformable to electrically connect to the second electrode terminal.

[0048] In the above scheme, by providing the second deformation member, when the internal pressure of the battery cell reaches a certain degree, for example, a second threshold value, the second electrode terminal is caused to electrically connect to the second wall by deformation of the second deformation member, so that the short circuit of the first deformation member and the first electrode terminal is caused to melt the electrical connection member in the battery cell due to a large current generated by the short circuit, so as to cut off the charging and discharging circuit of the battery cell, thereby achieving the overcharge protection function and reducing the risk of thermal runaway of the battery cell, and thereby improving the reliability of the battery device. On the other hand, since the first electrode terminal and the second electrode terminal are insulated from the first wall under normal working conditions, the shell of the battery cell can be uncharged, which is beneficial to the energy storage device formed by the battery cell, and the risk of sparking breakdown between two adjacent battery cells in the energy storage device is small.

[0049] According to some embodiments of the present application, the second electrode terminal is a negative electrode terminal, so that the minimum pressure value for deforming the second deformation member is greater than the minimum pressure value for deforming the first deformation member.

[0050] In the above scheme, when the second electrode terminal is a negative electrode terminal, by making the minimum pressure value for deforming the second deformation piece greater than the minimum pressure value for deforming the first deformation piece, the second deformation piece can be deformed when the pressure inside the battery monomer is greater than the first deformation piece. On the one hand, the battery monomer can have an overcharge protection function, on the other hand, the risk of the second deformation piece being turned over to cause the shell to be negatively charged and corroded by the electrolyte due to gas production inside the battery monomer under non-overcharge abuse conditions can be reduced, thereby ensuring the integrity of the shell to a certain extent, reducing the risk of electrolyte leakage, and thus providing the reliability of the battery device.

[0051] In a second aspect, some embodiments of the present application provide a battery device comprising a plurality of battery monomers as provided in the first aspect.

[0052] In a third aspect, some embodiments of the present application provide an energy storage device comprising a plurality of battery monomers as provided in the first aspect and / or a battery device as provided in the second aspect.

[0053] According to some embodiments of the present application, the capacity of the battery monomer is greater than or equal to 280 Ah.

[0054] In a fourth aspect, some embodiments of the present application provide a power consumption device comprising a battery monomer as provided in the first aspect, the battery monomer being used to provide electrical energy.

[0055] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0057] FIG. 1 is a schematic view of a vehicle in some embodiments of the present application;

[0058] FIG. 2 is a schematic view of an energy storage device in some embodiments of the present application;

[0059] FIG. 3 is a perspective exploded view of a battery in some embodiments of the present application;

[0060] FIG. 4 is a perspective exploded view of a battery monomer in some embodiments of the present application;

[0061] FIG. 5 is a schematic view of a first pole piece in some embodiments of the present application;

[0062] FIG. 6 is a schematic view of a positive electrode tab in some embodiments of the present application;

[0063] FIG. 7 is a schematic view of a positive electrode tab in some embodiments of the present application;

[0064] FIG. 8 is a perspective exploded view of a partial structure of a battery cell in some embodiments of the present application;

[0065] FIG. 9 is a schematic view of an internal structure of a partial structure of a battery cell in some embodiments of the present application;

[0066] FIG. 10 is a schematic view of a first wall, a first electrode terminal, and a first deformation member in some embodiments of the present application;

[0067] FIG. 11 is a schematic view of a first deformation member in some embodiments of the present application;

[0068] FIG. 12 is a schematic view of a first wall, a second electrode terminal, and a second deformation member in some embodiments of the present application.

[0069] FIG. 13 is a schematic view of a second deformation member in some embodiments of the present application.

[0070] The embodiments of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot be used to limit the protection scope of the present application.

[0071] ​Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application; the use of the terms "including," "comprising," or "having" and variations thereof herein is intended to be broad and encompass the terms "consisting of" and "consisting essentially of" and variations thereof. Unless otherwise noted, the terms "including" and "comprising" are open-ended and do not exclude the presence of unrecited elements or limitations.

[0072] In the description of the embodiments of the present application, the technical terms "first", "second", and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0073] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0074] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent: A exists, A and B exist, and B exists. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0075] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0076] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0077] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mount", "connect", "connect", "fix", and other terms should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0078] In the present application, the battery cell can include a lithium ion secondary battery, a lithium ion primary battery, a lithium-sulfur battery, a sodium lithium ion battery, a sodium ion battery, or a magnesium ion battery, etc. The embodiments of the present application are not limited thereto. The battery cell can be in the shape of a rectangular parallelepiped or other shapes, etc. The embodiments of the present application are also not limited thereto. The battery referred to in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. The battery device generally includes a box for packaging one or more battery cells. The box can to some extent avoid the influence of liquid or other foreign matters on the charging or discharging of the battery cell.

[0079] The battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode tab, a negative electrode tab, and a separator. The battery cell mainly relies on the movement (e.g. deintercalation) of metal ions between the positive electrode tab and the negative electrode tab to work. The positive electrode tab includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector that is not coated with the positive electrode active material layer protrudes from the positive electrode current collector that has been coated with the positive electrode active material layer, and the positive electrode current collector that is not coated with the positive electrode active material layer serves as a positive electrode tab. Taking a lithium ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode tab includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector that is not coated with the negative electrode active material layer protrudes from the negative electrode current collector that has been coated with the negative electrode active material layer, and the negative electrode current collector that is not coated with the negative electrode active material layer serves as a negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon, etc. In order to ensure a certain degree of safety from melting under a large current, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly can be a winding type structure or a stacking type structure, and the embodiments of the present application are not limited thereto.

[0080] The battery cell further includes a housing, an electrode assembly, and an electrolyte disposed inside the housing. The housing has a first wall provided with an electrode terminal connected with the electrode assembly, the electrode terminal being used for input and output of electric energy. Generally, the electrode terminal includes a conductive piece outside the first wall for connecting a busbar to achieve input and output of electric energy, and a pole post at least partially inside the first wall for connecting a tab.

[0081] The development of battery technology needs to consider various design factors, such as performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge rate, and in addition, the reliability of the battery device.

[0082] To reduce the risk of thermal runaway of the battery cell under abuse conditions such as overcharging, some battery cells currently have an overcharge protection mechanism. The overcharge protection mechanism can include an SSD (safety short circuit device) or a CID (current interrupt device) triggered by a certain pressure. Illustratively, the battery cell is provided with a short circuit component, which includes a deformation piece electrically connected with the housing. Under abuse conditions such as overcharging, when the internal pressure of the battery cell grows to a certain extent, for example, reaches a threshold, the deformation piece deforms under the action of the internal pressure to electrically connect with the conductive piece, causing the housing and the electrode terminal to be short-circuited, resulting in internal short-circuit of the battery cell, and the internal electrical connection component of the battery cell is fused due to the large current generated by the short circuit, thereby cutting off the charge / discharge circuit of the battery cell, playing a role in overcharge protection. However, the corresponding time of the internal pressure of the battery cell is slow under the action of heat / voltage, and there is a risk that the internal temperature of the battery cell has accumulated to a high level, but the internal pressure has not reached the threshold, and the overcharge protection mechanism has not been triggered, affecting the reliability of the battery device.

[0083] In view of this, to improve the problem that the internal pressure of the battery cell currently grows slowly, resulting in that the internal temperature of the battery cell has accumulated to a high level, but the internal pressure has not reached the threshold, resulting in that the overcharge protection mechanism has not been triggered, affecting the reliability of the battery device, some embodiments of the present application provide a battery cell. The battery includes a housing, an electrode assembly, and an overcharge protection mechanism. The housing has a first wall, the electrode assembly is disposed inside the housing, and the overcharge protection mechanism is disposed on the first wall. The electrode assembly includes a gas generator, and the gas generator includes at least one of a carbonate, an oxalate, or a chloride.

[0084] In the above scheme, by arranging the gas generating agent in the electrode assembly, when the voltage of the battery monomer increases to a certain extent due to misuse such as overcharging, the gas generating agent decomposes to generate gas before the main electrochemical substance of the battery monomer, so that the internal pressure of the battery monomer increases in advance to trigger the overcharge protection mechanism in advance to achieve overcharge protection, thereby reducing the risk of thermal runaway of the battery monomer due to the decomposition of the main electrochemical substance of the battery monomer to generate a large amount of heat, and further improving the reliability of the battery device.

[0085] The technical solutions described in the embodiments of the present application are suitable for battery devices and energy storage devices using battery monomers and / or battery devices, and power consumption devices using battery monomers and / or battery devices.

[0086] The energy storage device can include an energy storage container, an energy storage cabinet, etc. For example, the energy storage cabinet can include a cabinet body and one or more battery monomers arranged on the cabinet body. In some embodiments, the capacity of each battery monomer in the energy storage device can be greater than or equal to 280 Ah (ampere-hour).

[0087] The power consumption device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, and an electric tool, etc. The vehicle can be a new energy vehicle, which can be a pure electric vehicle, a hybrid vehicle, or an extended range vehicle, etc. The spacecraft includes an airplane, a rocket, a space shuttle, a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric plane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, etc.

[0088] The following embodiments are described for convenience with the power consumption device being a vehicle as an example.

[0089] FIG. 1 is a schematic diagram of a vehicle in some embodiments of the present application.

[0090] The interior of the vehicle 1000 can be provided with the controller 200, the motor 300, and the battery device 100, the controller 200 being configured to control the battery device 100 to supply power to the motor 300. For example, the battery can be arranged at the bottom or the front or the rear of the vehicle 1000. The battery device 100 can be used to supply power to the vehicle 1000, for example, the battery device 100 can be used as the operating power source of the vehicle 1000, and can be used for the circuit system of the vehicle 1000, for example, for the power demand of the vehicle 1000 during starting, navigation, and operation. In another embodiment of the present application, the battery device 100 can not only be used as the operating power source of the vehicle 1000, but also can be used as the driving power source of the vehicle 1000, to replace or partially replace the fuel or natural gas to provide driving power for the vehicle 1000.

[0091] Referring to FIG. 2, FIG. 2 is a schematic diagram of an energy storage device according to some embodiments of the present application.

[0092] The energy storage device 2000 can include a cabinet 2001 and a plurality of battery devices 100. The plurality of battery devices 100 can be arranged in the cabinet 2001. The plurality of battery devices 100 can be connected in series, in parallel, or in a hybrid manner.

[0093] Referring to FIG. 3, FIG. 3 is a perspective exploded view of a battery according to some embodiments of the present application.

[0094] The battery device 100 includes a battery cell 10 and a box 30, and the battery cell 10 is accommodated in the box 30. The box 30 is configured to provide an accommodation space for the battery cell 10, and the box 30 can have various structures. In some embodiments, the box 30 can include a first box part 31 and a second box part 32, the first box part 31 and the second box part 32 are overlapped with each other, and the first box part 31 and the second box part 32 together define an accommodation space for accommodating the battery cell 10. The second box part 32 can be a hollow structure with one end open, and the first box part 31 can be a plate structure, the first box part 31 is overlapped with the open end of the second box part 32, so that the first box part 31 and the second box part 32 together define the accommodation space; the first box part 31 and the second box part 32 can also be hollow structures with one side open, and the open end of the first box part 31 is overlapped with the open end of the second box part 32. Of course, the box 30 formed by the first box part 31 and the second box part 32 can have various shapes, such as a cylinder, a cuboid, etc.

[0095] In the battery device 100, the battery cell 10 can be one or a plurality of battery cells, and each battery cell 10 can be fixed to the box 30 by a connecting member (such as a bolt), or each battery cell 10 can be fixed to the box 30 by an adhesive.

[0096] Some embodiments of the present application provide a battery cell 10. Please refer to FIG. 4, which is a perspective exploded view of the battery cell 10 according to some embodiments of the present application.

[0097] The battery cell 10 includes a housing 11, an electrode assembly 12, and an overcharge protection mechanism 13 (please refer to FIG. 9). The housing 11 has a first wall 111, the electrode assembly 12 is disposed in the housing 11, and the overcharge protection mechanism 13 is disposed on the first wall 111. The electrode assembly 12 includes a gas generating agent, which includes at least one of a carbonate, an oxalate, or a chloride.

[0098] The housing 11 is a component for accommodating the electrode assembly 12, and can also be used to accommodate an electrolyte, such as an electrolyte solution. Please refer to FIG. 4, in some embodiments, the housing 11 includes a shell 110 and an end cover. The shell 110 has an accommodation cavity formed inside for accommodating the electrode assembly 12, and has an opening communicating with the accommodation cavity, and the end cover is coupled to the opening of the shell 110 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 12 and the electrolyte. The end cover can be connected to the shell 110 by welding, bonding, clamping, or other connection methods. Optionally, the housing 11 can also include a bottom plate, and the shell 110 has two openings at both ends, one of which is closed by the end cover and the other of which is closed by the bottom plate.

[0099] In some embodiments, the material of the housing 11 can be metal or a combination of metal and non-metal. For example, the housing 11 can be made of metal, such as aluminum, copper, iron, steel, or aluminum alloy; or for example, part of the housing 11 can be made of metal, and the rest can be made of non-metal, such as the end cover of the housing 11 can be made of metal, and the shell 110 or other parts of the housing 11 can be made of non-metallic material.

[0100] In some embodiments, the housing 11 can be a sealed structure or a non-sealed structure. As an example, when the housing 11 is a sealed structure, the housing 11 can protect the electrode assembly 12 and prevent leakage of the electrolyte, etc. When the housing 11 is a non-sealed structure, the housing 11 can protect the electrode assembly 12, and a sealing bag can be further included between the housing 11 and the electrode assembly 12, which is used to package the electrode assembly 12 and the electrolyte, etc. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum plastic film.

[0101] In some embodiments, when assembling the battery cell 10, the electrode assembly 12 can be first placed into the case 110, and the electrolyte is filled into the case 110, and then the end cover is covered on the opening of the case 110 to complete the assembly of the battery cell 10. Alternatively, in some embodiments, when assembling the battery cell 10, the electrode assembly 12 can be first placed into the case 110, and then the end cover is covered on the opening of the case 110, and then the electrolyte is filled into the case 110 through the liquid injection hole of the end cover, and then the liquid injection hole is closed to complete the assembly of the battery cell 10.

[0102] The case 11 can be in various shapes, such as a cylindrical structure or a prismatic structure. The shape of the case 11 can be determined according to the specific shape of the electrode assembly 12. For example, if the electrode assembly 12 is in a cylindrical structure, a cylindrical structure of the case 11 can be selected. If the electrode assembly 12 is in a flat structure, the case 11 can be square.

[0103] The electrode assembly 12 includes a first electrode sheet, a second electrode sheet, and a separator. The first electrode sheet and the second electrode sheet are opposite in polarity, for example, the first electrode sheet is a positive electrode sheet 124, and the second electrode sheet is a negative electrode sheet. The separator is between the first electrode sheet and the second electrode sheet and serves as a separation function. The electrode assembly 12 can be in a wound structure or a stacked structure, and the embodiments of the present application are not limited thereto. In some embodiments, the separator can be a PP (polypropylene) porous membrane, a PE (polyethylene) porous membrane, a polyimide porous membrane, and a porous membrane formed by various polymer composites.

[0104] Please refer to FIG. 5, which is a schematic diagram of the first electrode sheet in some embodiments of the present application. In some embodiments, the first electrode sheet is a positive electrode sheet 124, which includes a positive electrode current collector 1240 and a positive electrode active material layer 1241 coated on at least one side of the positive electrode current collector 1240 in the thickness direction.

[0105] In some embodiments, the positive electrode current collector 1240 without the positive electrode active material layer 1241 is protruded to form a positive electrode tab.

[0106] In some embodiments, the material of the positive current collector 1240 can include an aluminum foil, an aluminum foam, an aluminum composite current collector (a current collector with an aluminum metal layer on both surfaces of a high-molecular support layer in the middle), a nickel foil, a nickel foam, or the like. In some embodiments, the positive active material in the positive active material layer 1241 includes one or a mixture of several of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium-containing phosphate of an olivine structure, for example, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, or the like. In some embodiments, the binder in the positive active material layer 1241 is selected from at least one of vinylidene fluoride, a vinylidene fluoride-hexafluoropropylene copolymer, a polyacrylate, a sodium salt of carboxymethyl cellulose, a butadiene-styrene rubber, a polyurethane, an ethylene-vinyl acetate copolymer, and an ethylene-acrylic acid copolymer. In some embodiments, the dispersant in the positive active material layer 1241 is selected from polyvinylpyrrolidone or the like. In some embodiments, the conductive agent in the positive active material layer 1241 is selected from at least one of conductive carbon black (Super P), acetylene black, Ketjen black, carbon fiber, carbon nanotube, graphene, activated carbon, graphite sheet, graphite particle, and mesocarbon microbead.

[0107] In some embodiments, the positive electrode sheet 124 can be prepared by dispersing the components described above for preparing the positive electrode sheet 124, such as the positive active material, the conductive agent, the binder, and any other components, in a solvent (for example, N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on the positive current collector 1240; and performing processes such as drying, cold pressing, or the like to obtain the positive electrode sheet 124.

[0108] In some embodiments, the negative electrode tab includes a negative electrode current collector and a negative electrode active material layer 1241 coated on at least one side of the negative electrode current collector in the thickness direction. The negative electrode current collector not coated with the negative electrode active material layer 1241 protrudes from the negative electrode current collector coated with the negative electrode active material layer 1241, and the negative electrode current collector not coated with the negative electrode active material layer 1241 serves as a negative electrode tab. In some embodiments, the material of the negative electrode current collector can include a copper foil, a copper alloy foil, a nickel foil, a stainless steel foil, a titanium foil, a foamed nickel, a foamed copper, or a polymer substrate coated with a conductive metal, wherein the conductive metal includes but is not limited to copper, nickel, or titanium, and the material of the polymer substrate includes but is not limited to at least one of polyethylene, polypropylene, ethylene propylene copolymer, polyethylene terephthalate, polyethylene naphthalate, and polyphenylene terephthalamide. In some embodiments, the negative electrode active material in the negative electrode active material layer includes a carbon material, lithium monomer, an alloy of lithium and other metal elements or non-metal elements, wherein the carbon material includes but is not limited to at least one of hard carbon, soft carbon, amorphous carbon, nanostructured carbon material, etc., all of which can be obtained through commercial channels. The metal elements include tin (Sn), zinc (Zn), aluminum (Al), magnesium (Mg), silver (Ag), gold (Au), gallium (Ga), indium (In), foil (Pt), etc., and the non-metal elements include boron (B), carbon (C), silicon (Si), etc.

[0109] In some embodiments, the electrolyte functions to conduct ions between the positive electrode tab 124 and the negative electrode tab. The application does not have specific limitations on the type of electrolyte, which can be selected as needed. For example, the electrolyte can be liquid, gel, or all-solid-state. In some embodiments, the electrolyte uses an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent. In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoroboric oxalate, lithium difluorophosphoric oxalate, and lithium tetrafluorophosphoric oxalate. In some embodiments, the solvent can 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, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclobutane sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0110] In some embodiments, the electrolyte solution can also optionally include an additive. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and can also include an additive capable of improving certain performance of the battery, such as an additive capable of improving overcharge performance of the battery, an additive capable of improving high-temperature or low-temperature performance of the battery, etc.

[0111] In some embodiments, the first wall 111 is part of the structure of the housing 110. The first wall 111 can be used to support the first electrode terminal 14, such that the first electrode terminal 14 is in a stable state to achieve input and output of electric energy. In some embodiments, the first wall 111 can be part of the housing 110, such as a side wall or a bottom wall of the housing 110. In some embodiments, the first wall 111 can be an end cap. The first electrode terminal 14 is electrically connected to the electrode assembly 12, for example, to allow current to flow into or out of the first tab 120 via the first electrode terminal 14. The first electrode terminal 14 and the first tab 120 have the same polarity. In some embodiments, the first electrode terminal 14 is made of a metal material, such as aluminum, copper, iron, aluminum, steel, alloy, or composite metal. In some embodiments, the first electrode terminal 14 can be connected to the first tab 120 of the electrode assembly 12 via the first adapter 121 or the first electrode terminal 14 can be directly connected to the first tab 120. In some embodiments, the first tab 120 of the electrode assembly 12 is composed of a plurality of first sub-tabs stacked together, and the first adapter 121 can be welded at one end to the first tab 120 and at the other end to the first electrode terminal 14. In some embodiments, the first wall 111 can also be provided with a second electrode terminal 16, which can be connected to the second tab 122 via a second adapter 123. The second electrode terminal 16 has a polarity opposite to that of the first electrode terminal 14, for example, the first electrode terminal 14 is positive and the second electrode terminal 16 is negative.

[0112] The overcharge protection mechanism 13 is a component provided on the first wall 111, and the overcharge protection mechanism 13 can be used to achieve overcharge protection of the battery cell 10. For example, when the battery cell 10 is in an overcharge or other abuse condition, the overcharge protection mechanism 13 can be triggered by the internal pressure of the battery cell 10, so as to take corresponding action to achieve the purpose of cutting off the charge and discharge circuit of the battery cell 10.

[0113] Exemplarily, the overcharge protection mechanism 13 can comprise a short-circuit component (SSD), which can comprise a deformation member (e.g. a flip tab), the deformation member being electrically connected with the first wall 111, the first electrode terminal 14 being insulatedly arranged on the first wall 111. When the battery cell 10 is in an overcharge or other abuse condition, the internal pressure increases, and when the internal pressure reaches a certain level, the deformation member deforms to electrically connect with the first electrode terminal 14, thereby turning on the first wall 111 and the first electrode terminal 14, so that the internal positive and negative electrodes of the battery cell 10 are short-circuited, and the large current generated instantaneously can melt the electrical connection component inside the battery cell 10, thereby cutting off the charging and discharging circuit of the battery cell 10, thereby playing a role of overcharge protection. The melted electrical connection component can comprise the first adapter 121 and / or the second adapter 123. Exemplarily, the first adapter 121 has a first melting portion, the thickness or width dimension of the first melting portion can be smaller than that of the rest of the first adapter 121, so that when a larger current passes through, the first melting portion can be melted, thereby breaking the current path of the first tab 120 and the first electrode terminal 14.

[0114] Exemplarily, the overcharge protection mechanism 13 can comprise a circuit-breaking component (CID), which can comprise a deformation member and a current-cutting structure. The first electrode terminal 14 can be connected with the first adapter 121 through the circuit-breaking component. When the battery cell 10 is in an overcharge or other abuse condition, the internal pressure increases, and when the internal pressure reaches a certain level, the deformation member deforms to pull apart the current-cutting structure, so that the circuit of the first electrode terminal 14 and the first adapter 121 is broken, thereby cutting off the charging and discharging circuit of the battery cell 10, thereby playing a role of overcharge protection.

[0115] The “electrode assembly 12 comprises a gas generating agent” can be understood as that the electrode assembly 12 contains the gas generating agent, i.e. the gas generating agent is inside the housing 11 when the electrode assembly 12 is assembled in the housing 11.

[0116] The gas generating agent is configured to decompose to generate gas to trigger the overcharge protection mechanism 13

[0117] In some embodiments, the gas generating agent is a voltage sensitive gas generating agent. The "voltage sensitive gas generating agent" can be understood as a gas generating agent that generates gas under the stimulation of voltage change, for example, after the charging voltage reaches a certain threshold, the gas generating agent will decompose and generate gas. In some embodiments, the voltage at which the gas generating agent decomposes is greater than the normal operating voltage of the battery cell 10, and the voltage at which the gas generating agent decomposes can be less than the voltage at which the main electrochemical substance of the battery cell 10 decomposes to generate gas. For example, taking the battery cell 10 of the lithium iron phosphate system as an example, the normal operating voltage of the battery cell 10 of the lithium iron phosphate system is generally less than 3.7 volts, for example, 3.65V, and the voltage at which the main electrochemical substance decomposes to generate gas is 4.5 volts. Therefore, a gas generating agent that decomposes to generate gas at a voltage between 3.7 volts and 4.5 volts can be selected.

[0118] In some embodiments, the gas generating agent can be included in the positive electrode sheet 124. In some embodiments, the gas generating agent can be included in the separator. In some embodiments, the gas generating agent can be included in the negative electrode sheet.

[0119] For example, the positive electrode sheet 124 includes a gas generating agent. In one case, the gas generating agent can be contained in the positive electrode active material layer 1241. In another case, the gas generating agent can be formed into a gas generating layer 1242, which can be located on the side of the positive electrode active material layer 1241 away from the positive electrode current collector 1240, or the gas generating layer 1242 can be located between the positive electrode active material layer 1241 and the positive electrode current collector 1240.

[0120] In the above scheme, by providing a voltage sensitive gas generating agent in the electrode assembly 12, when the battery cell 10 is caused to overcharge or the like under abuse conditions, the voltage of the battery cell 10 increases to a certain extent, so that the gas generating agent decomposes to generate gas before the main electrochemical substance of the battery cell 10, so that the internal pressure of the battery cell 10 increases in advance to make the overcharge protection mechanism 13 (safety short circuit device (SSD) or current interrupt device (CID)) be triggered in advance to achieve overcharge protection, thereby reducing the risk of thermal runaway of the battery cell 10 due to the decomposition of the main electrochemical substance of the battery cell 10 to generate a large amount of heat, and thereby improving the reliability of the battery device.

[0121] According to some embodiments of the present application, the gas generating agent includes at least one of a carbonate salt, an oxalate salt, or a chloride salt.

[0122] In some embodiments, the gas generating agent can include at least one of a carbonate salt, an oxalate salt, or a chloride salt. For example, in some embodiments, the gas generating agent can include a carbonate salt. For example, in some embodiments, the gas generating agent can include an oxalate salt. In some embodiments, the gas generating agent can include a chloride salt. In some embodiments, the gas generating agent can include any two of a carbonate salt, an oxalate salt, or a chloride salt. In some embodiments, the gas generating agent can include all of a carbonate salt, an oxalate salt, and a chloride salt.

[0123] In some embodiments, the carbonate salt can include at least one of lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, or aluminum carbonate. In some embodiments, the oxalate salt can include at least one of lithium oxalate, sodium oxalate, potassium oxalate, magnesium oxalate, calcium oxalate, or aluminum oxalate. In some embodiments, the chloride salt can include at least one of lithium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, or aluminum chloride.

[0124] In the above scheme, when the gas generating agent includes at least one of a carbonate salt, an oxalate salt, or a chloride salt, the gas can be effectively decomposed to trigger the overcharge protection mechanism 13 in advance when the operating voltage of the battery cell 10 is at a specific value and less than the decomposition voltage of the main electrochemical substance of the battery cell 10, thereby balancing the normal charging and discharging of the battery cell 10 and the timeliness of the overcharge protection, and further improving the reliability of the battery cell 10.

[0125] According to some embodiments of the present application, the gas generating agent includes at least one of a carbonate salt of lithium, sodium, potassium, magnesium, calcium, or aluminum.

[0126] In some embodiments, the gas generating agent can include at least one of lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, or aluminum carbonate.

[0127] For example, the gas generating agent can include lithium carbonate, which decomposes into lithium oxide and carbon dioxide when the charging voltage of the battery cell 10 is greater than 4.3 volts.

[0128] In the above scheme, by including at least one of a carbonate salt of lithium, sodium, potassium, magnesium, calcium, or aluminum in the gas generating agent, the gas generated by the decomposition of the gas generating agent can include carbon dioxide, which can trigger the overcharge protection mechanism 13 in advance and improve the anti-explosion performance of the battery cell 10, thereby effectively improving the reliability of the battery device.

[0129] According to some embodiments of the present application, the gas generating agent includes at least one of lithium carbonate, lithium oxalate, or lithium chloride.

[0130] In some embodiments, the gas generating agent can include lithium carbonate, which decomposes into lithium oxide and carbon dioxide when the charging voltage of the battery cell 10 is greater than its normal operating voltage by a certain degree.

[0131] In some embodiments, the gas generating agent includes lithium oxalate, and when the charging voltage of the battery cell 10 is greater than its normal operating voltage to a certain extent, the decomposition product of the lithium oxalate can include carbon dioxide and lithium oxide.

[0132] In some embodiments, the gas generating agent includes lithium chloride, and when the charging voltage of the battery cell 10 is greater than its normal operating voltage to a certain extent, the decomposition product of the lithium chloride can include chlorine and metallic lithium.

[0133] In the above scheme, by including at least one of lithium carbonate, lithium oxalate or lithium chloride in the gas generating agent, the gas generating agent can be decomposed at a suitable voltage, so as to take into account the normal charging and discharging of the battery cell 10 and the timeliness of the overcharge protection, thereby making the reliability of the battery cell 10 high.

[0134] According to some embodiments of the present application, the electrode assembly 12 includes a pole piece, and the gas generating agent is arranged on the pole piece.

[0135] In some embodiments, the "gas generating agent arranged on the pole piece" can include the following schemes: the gas generating agent is arranged in the active material layer 1241, or the gas generating agent is a separate structure layer, for example, the gas generating agent is formed into a gas generating layer 1242, and the gas generating layer 1242 is arranged on the pole piece. For example, the active material, the binder, the conductive agent and the gas generating agent are added to the solvent in a certain mass ratio and uniformly mixed to form an active material slurry, the active material slurry is coated on the current collector, and after drying, cold pressing and other processes, the active material layer 1241 is formed.

[0136] For example, the gas generating agent is formed into a gas generating layer 1242, and the gas generating layer 1242 is a separate structure layer in the pole piece. For example, the binder, the conductive agent and the gas generating agent are added to the solvent in a certain mass ratio and uniformly mixed to form a gas generating slurry, the gas generating slurry is coated on the current collector or the active material layer 1241, and after drying, cold pressing and other processes, the gas generating layer 1242 is formed.

[0137] In the above scheme, by arranging the gas generating agent on the pole piece, on the one hand, the process of arranging the gas generating agent on the pole piece is simple, which can effectively reduce the influence of arranging the gas generating agent on the manufacturing efficiency of the battery cell 10, and on the other hand, the gas generating agent can be effectively provided with an electric decomposition condition, and the gas can be effectively decomposed to trigger the overcharge protection mechanism 13 in advance, so as to realize the timeliness of the overcharge protection, thereby making the reliability of the battery cell 10 high.

[0138] According to some embodiments of the present application, the pole piece includes a positive pole piece 124, and the gas generating agent is arranged on the positive pole piece 124.

[0139] In some embodiments, the gas generating agent can be disposed in the positive electrode tab 124, for example, the gas generating agent can be disposed in the positive electrode active material layer 1241. Alternatively, in some embodiments, the gas generating agent is formed into a gas generating layer 1242, which is disposed between the positive electrode current collector 1240 and the positive electrode active material layer 1241, or between the positive electrode current collector 1240 and the gas generating layer 1242.

[0140] According to some embodiments of the present application, please refer to FIG. 5, the positive electrode tab 124 includes a positive electrode current collector 1240 and a positive electrode active material layer 1241 coated on the surface of the positive electrode current collector 1240, and the gas generating agent is disposed in the positive electrode active material layer 1241.

[0141] In some embodiments, the gas generating agent can be a material in the positive electrode active material layer 1241, that is, the gas generating agent is contained in the positive electrode active material slurry. For example, the positive electrode active material (lithium iron phosphate), the binder (polyvinylidene fluoride), the conductive agent (conductive carbon black) and the gas generating agent (lithium carbonate) are added into the solvent in a certain mass ratio and uniformly mixed to form a positive electrode active material slurry, the positive electrode active material slurry is coated on the positive electrode current collector 1240, and after drying, cold pressing and other processes, the active material layer 1241 is formed, and through slitting, die cutting and other processes, the positive electrode tab 124 is formed.

[0142] In the above scheme, by disposing the gas generating agent in the positive electrode active material layer 1241, the influence of the gas generating agent on the charge and discharge performance of the battery monomer 10 can be effectively reduced, the timeliness of the overcharge protection and the charge and discharge performance of the battery monomer 10 can be considered, and the reliability of the battery device can be effectively improved.

[0143] According to some embodiments of the present application, the positive electrode active material layer 1241 includes a positive electrode active material, a binder, a conductive agent and a gas generating agent.

[0144] In some embodiments, the positive electrode active material layer 1241 can be composed of a positive electrode active material, a binder, a conductive agent and a gas generating agent. For example, the positive electrode active material layer 1241 can be prepared by mixing the positive electrode active material, the binder, the conductive agent and the gas generating agent in the solvent and through coating, drying and other processes.

[0145] In some embodiments, the binder includes but is not limited to polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer, polyacrylate, sodium carboxymethyl cellulose, butadiene-styrene rubber, polyurethane, ethylene-vinyl acetate copolymer or ethylene-acrylic acid copolymer, etc. The conductive agent includes but is not limited to conductive carbon black (Super P), acetylene black, ketjen black, carbon fiber, carbon nanotube, graphene, activated carbon, graphite sheet or graphite particle, etc.

[0146] Exemplarily, the positive electrode active material (lithium iron phosphate (LFP)), the binder (polyvinylidene fluoride (PVDF)), the conductive agent (Super P), and the gas generating agent lithium carbonate are added into N-methyl pyrrolidone solvent in a mass ratio of 96.5:1.5:1.5:0.5, uniformly mixed to form a slurry, uniformly coated on an aluminum foil, and then dried, cold-pressed, divided, and laser-cut to form the positive electrode sheet 124.

[0147] In the above scheme, the positive electrode active material layer 1241 is composed of a positive electrode active material, a binder, a conductive agent, and a gas generating agent. On the one hand, the mixture of the gas generating agent can decompose and generate gas before the main electrochemical substances of the battery monomer 10 to increase the internal pressure of the battery monomer 10 to trigger the overcharge protection mechanism 13 to achieve overcharge protection when the battery monomer 10 is overcharged or in other abuse conditions, thereby improving the reliability of the battery device. On the other hand, compared with the current scheme of adding an activator to activate the gas generating agent, in some embodiments of the present application, the positive electrode active material layer 1241 can be composed of a positive electrode active material, a binder, a conductive agent, and a gas generating agent. The battery monomer 10 can decompose and generate gas to trigger the overcharge protection mechanism 13 when the voltage reaches a certain value, and the mass and volume energy density is higher, so the energy density and reliability of the battery monomer are considered.

[0148] According to some embodiments of the present application, the mass ratio of the gas generating agent in the positive electrode active material layer 1241 is 0.1% to 10%.

[0149] In some embodiments, when the positive electrode active material layer 1241 contains a gas generating agent, the mass ratio of the gas generating agent in the positive electrode active material layer 1241 can be not less than 0.1% and not more than 10%. For example, the mass ratio of the gas generating agent in the positive electrode active material layer 1241 can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 5%, 5.1%, 5.2%, 9.5%, 9.5%, 9.6%, 9.7%, 9.8%, 9.9%, 10%, or any value between two adjacent values.

[0150] Exemplarily, the positive electrode active material (lithium iron phosphate (LFP)), the binder (polyvinylidene fluoride (PVDF)), the conductive agent (Super P), and the gas generating agent lithium carbonate are added into N-methyl pyrrolidone solvent in a mass ratio of 96.5:1.5:1.5:0.5, uniformly mixed to form a slurry, uniformly coated on an aluminum foil, and then dried, cold-pressed, divided, and laser-cut to form the positive electrode sheet 124.

[0151] In the above scheme, by setting the mass ratio of the gas generating agent in the positive electrode active material layer 1241 to 0.1% to 10%, the charge-discharge performance of the battery monomer 10 and the timeliness of overcharge protection can be considered.

[0152] According to some embodiments of the present application, the mass ratio of the gas generating agent in the positive electrode active material layer 1241 is 0.5% to 5%.

[0153] In some embodiments, when the positive electrode active material layer 1241 contains a gas generating agent, the mass ratio of the gas generating agent in the positive electrode active material layer 1241 can be no less than 0.5% and no more than 5.0%, for example, the mass ratio of the gas generating agent in the positive electrode active material layer 1241 can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.2%, 1.3%, 1.4%, 1.5%, …, 4.8%, 4.9%, 5.0% or any value between two adjacent values.

[0154] For example, the positive electrode active material (lithium iron phosphate (LFP)), the binder (polyvinylidene fluoride (PVDF)), the conductive agent (Super P), and the gas generating agent lithium carbonate are added to the N-methyl pyrrolidone solvent in a mass ratio of 96:1.5:1.5:1.0, uniformly mixed to form a slurry, and then uniformly coated on an aluminum foil. After drying, cold pressing, slitting, and laser cutting, the positive electrode sheet 124 is formed.

[0155] In the above scheme, by setting the mass ratio of the gas generating agent in the positive electrode active material layer 1241 to 0.5% to 1.5%, the charge-discharge performance of the battery monomer 10 and the timeliness of overcharge protection can be further considered.

[0156] According to some other embodiments of the present application, please refer to FIG. 6, which is a schematic diagram of the positive electrode sheet 124 in some other embodiments of the present application. The positive electrode sheet 124 includes a positive electrode current collector 1240, a gas generating layer 1242, and a positive electrode active material layer 1241, the positive electrode active material layer 1241 is arranged between the positive electrode current collector 1240 and the gas generating layer 1242, and the gas generating layer 1242 includes a gas generating agent, a binder and a conductive agent.

[0157] In some embodiments, the gas generating agent is arranged between the positive electrode active material layer 1241 and the positive electrode current collector 1240 in the form of a gas generating layer 1242.

[0158] In some embodiments, the binder includes, but is not limited to, polyvinylidene fluoride (PVDF), vinylidene-hexafluoropropylene copolymer, polyacrylate, sodium carboxymethyl cellulose, styrene butadiene rubber, polyurethane, ethylene-vinyl acetate copolymer, or ethylene-acrylic acid copolymer, etc. The conductive agent includes, but is not limited to, conductive carbon black (Super P), acetylene black, ketjen black, carbon fiber, carbon nanotube, graphene, activated carbon, graphite sheet, or graphite particle, etc.

[0159] In some embodiments, the gas generating layer can be composed of a gas generating agent, a binder, and a conductive agent. Exemplarily, a positive electrode active material (lithium iron phosphate (LFP)), a binder (polyvinylidene fluoride (PVDF)), and a conductive agent (Super P) are added into a solvent (N-methyl pyrrolidone) in a certain mass ratio, uniformly mixed to form a slurry, and then uniformly coated on an aluminum foil to form a positive electrode active material layer 1241 after drying. A binder (polyvinylidene fluoride (PVDF)), a conductive agent (Super P), and a gas generating agent (lithium carbonate) are added into a solvent (N-methyl pyrrolidone) in a certain mass ratio, uniformly mixed to form a slurry, and then uniformly coated on the positive electrode active material layer 1241 to form a gas generating layer 1242 after drying. After processes such as cold pressing and slitting, a positive electrode sheet 124 is formed.

[0160] In the above scheme, on the one hand, the process is simple, the gas generating layer 1242 is easy to coat, and the timeliness of overcharge protection is improved to improve the reliability of the battery device. On the other hand, compared with the current scheme of adding an activator to trigger the gas generating agent, the gas generating layer in the battery monomer 10 provided by some embodiments of the present application can be composed of a gas generating agent, a binder, and a conductive agent, so that the battery monomer 10 can make the gas generating agent decompose to generate gas to trigger the overcharge protection mechanism 13 when the voltage reaches a certain value, thereby facilitating the control of the mass and volume energy density of the battery monomer 10, and making the mass and volume energy density of the battery device high.

[0161] According to some other embodiments of the present application, please refer to FIG. 7, which is a schematic diagram of a positive electrode sheet 124 in some other embodiments of the present application. The positive electrode sheet 124 includes a positive electrode current collector 1240, a gas generating layer 1242, and a positive electrode active material layer 1241. The gas generating layer 1242 is arranged between the positive electrode current collector 1240 and the positive electrode active material layer 1241, and includes a gas generating agent, a binder, and a conductive agent.

[0162] In some embodiments, the gas generating agent is disposed between the positive active material layer 1241 and the positive current collector 1240 in a state of the gas generating layer 1242. In some embodiments, the binder includes, but is not limited to, polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer, polyacrylate, sodium carboxymethyl cellulose, butadiene-styrene rubber, polyurethane, ethylene-vinyl acetate copolymer, or ethylene-acrylic acid copolymer, etc. The conductive agent includes, but is not limited to, conductive carbon black (Super P), acetylene black, ketjen black, carbon fiber, carbon nanotube, graphene, activated carbon, graphite flake, or graphite particle, etc.

[0163] In some embodiments, the gas generating layer 1242 is composed of the gas generating agent, the binder, and the conductive agent. For example, the binder (polyvinylidene fluoride (PVDF)), the conductive agent (Super P), and the gas generating agent (lithium carbonate) are added to a solvent (N-methylpyrrolidone) in a certain mass ratio, uniformly mixed to form a slurry, uniformly coated on an aluminum foil, and dried to form the gas generating layer 1242. The positive active material (lithium iron phosphate (LFP)), the binder (polyvinylidene fluoride (PVDF)), and the conductive agent (Super P) are added to the N-methylpyrrolidone solvent in a certain mass ratio, uniformly mixed to form a slurry, uniformly coated on the gas generating layer 1242, and dried to form the positive active material layer 1241. After cold pressing and slitting, the positive electrode sheet 124 is formed.

[0164] In the above scheme, the gas generating layer 1242 can be disposed on the positive current collector 1240 before the coating process. On the one hand, the process is simple, the gas generating layer 1242 is easy to coat, and the timeliness of the overcharge protection is beneficial to improve the reliability of the battery device. On the other hand, compared with the current scheme of adding an activator to trigger the gas generating agent, the gas generating layer in the battery monomer 10 provided by some embodiments of the present application can be composed of the gas generating agent, the binder, and the conductive agent, so that the battery monomer 10 can trigger the overcharge protection mechanism 13 by decomposing the gas generating agent to generate gas when the voltage reaches a certain value, thereby facilitating the control of the mass and volume energy density of the battery monomer 10, and making the mass and volume energy density of the battery device high.

[0165] According to some embodiments of the present application, please refer to FIGS. 8-11. FIG. 8 is a perspective exploded view of a partial structure of the battery monomer 10 according to some embodiments of the present application, FIG. 9 is an internal structure schematic view of the partial structure of the battery monomer 10 according to some embodiments of the present application, FIG. 10 is a schematic view of the first wall 111, the first electrode terminal 14, and the first deformation piece 130 according to some embodiments of the present application, and FIG. 11 is a schematic view of the first deformation piece 130 according to some embodiments of the present application.

[0166] The battery cell 10 further comprises a first electrode terminal 14, which is insulatedly arranged on the first wall 111. The overcharge protection mechanism 13 comprises a first deformation member 130, which is electrically connected with the first wall 111, and is configured to be deformable to electrically connect with the first electrode terminal 14.

[0167] In some embodiments, the first electrode terminal 14 is a component mounted on the first wall 111, and is insulated from the first wall 111. For example, an insulating structure is arranged between the first electrode terminal 14 and the first wall 111. The first electrode terminal 14 is used to electrically connect with the electrode assembly 12, so that the current flows into or out of the first tab 120 through the first electrode terminal 14.

[0168] The overcharge protection mechanism 13 can be a short-circuit component. In some embodiments, the overcharge protection mechanism 13 comprises a first deformation member 130. The first deformation member 130 is mounted on the first wall 111, and is electrically connected with the first wall 111. In some embodiments, the first deformation member 130 can be made of a metal material, for example, the first deformation member 130 is made of aluminum, copper, iron, aluminum, steel, alloy or composite metal. In some embodiments, the first deformation member 130 can be welded to the inner side of the first wall 111.

[0169] The first deformation member 130 is a structure member that deforms under the internal pressure of the battery cell 10. The first deformation member 130 is used for overcharge protection of the battery cell 10. For example, the gas generating agent decomposes to generate gas when the voltage exceeds a threshold value, resulting in an increase in the internal pressure of the battery cell 10. When the internal pressure reaches a certain level, for example, a first threshold value, the first deformation member 130 deforms to electrically connect with the first electrode terminal 14, thereby connecting the first wall 111 and the first electrode terminal 14 and causing the internal positive and negative electrodes of the battery cell 10 to be short-circuited. In some embodiments, the first deformation member 120 deforms to directly or indirectly contact the first electrode terminal 14 to electrically connect with the first electrode terminal 14. "Indirect contact" can be understood as that a conductive structure is arranged between the first deformation member 120 and the first electrode terminal 14. When the internal pressure of the battery cell 10 increases to the first threshold value, the first deformation member 120 deforms to contact the conductive structure to electrically connect with the first electrode terminal 14.

[0170] Exemplarily, the battery cell 10 is provided with a single short-circuit component, the first electrode terminal 14 is electrically connected with the first tab 120 through the first adapter 121, the second tab 122 of the electrode assembly 12 can be electrically connected with the first wall 111, the second tab 122 is opposite in polarity to the first tab 120, the second tab 122 is directly or through the second adapter 123 connected with the first wall 111, or the second electrode terminal 16 is provided on the first wall 111, the second electrode terminal 16 is electrically connected with the first wall 111, and the second tab 122 is directly or through the second adapter 123 connected with the second electrode terminal 16. The gas generating agent is decomposed to generate gas due to the voltage exceeding the threshold value, resulting in an increase in the internal pressure of the battery cell 10, when the internal pressure reaches a certain degree, for example, the first threshold value, the first deformation member 130 is deformed to short-circuit the first electrode terminal 14 and the first wall 111, so that the positive and negative electrodes inside the battery cell 10 are short-circuited to cause an internal short circuit, and a large current generated instantaneously can melt the electrical connection member inside the battery cell 10, cutting off the charge and discharge circuit of the battery cell 10, thereby playing a role of overcharge protection. The melted electrical connection member can include the first adapter 121 and / or the second adapter 123. Exemplarily, the first adapter 121 has a first melting portion, the thickness or width dimension of the first melting portion can be smaller than that of the rest of the first adapter 121, so that when a larger current passes through, the first melting portion can be melted to disconnect the current path of the first tab 120 and the first electrode terminal 14.

[0171] Exemplarily, the battery cell 10 is provided with two short-circuit components corresponding to the positive and negative electrodes respectively, including the first deformation member 130 and the second deformation member 131. The first electrode terminal 14 is insulatedly mounted on the first wall 111, and the first electrode terminal 14 is electrically connected with the first tab 120 through the first adapter 121, and the second electrode terminal 16 is insulatedly mounted on the first wall 111, and the second electrode terminal 16 is connected with the second tab 122 through the second adapter 123. The second electrode terminal 16 is correspondingly provided with the second deformation member 131, the second deformation member 131 is electrically connected with the first wall 111, and the second deformation member 131 is used to deform to electrically connect with the second electrode terminal 16 to electrically connect the second electrode terminal 16 with the first wall 111 when the internal pressure of the battery cell 10 reaches a certain degree, for example, the second threshold value.

[0172] The gas generating agent decomposes to generate gas when the voltage exceeds a threshold value, causing the internal pressure of the battery monomer 10 to increase. When the internal pressure reaches a certain level, for example, a first threshold value, the first deformation member 130 deforms to contact the first conductive member 140, short-circuiting the first electrode terminal 14 and the first wall 111. When the internal pressure of the battery monomer 10 reaches a second threshold value, the second deformation member 131 deforms to short-circuit the second electrode terminal 16 and the first wall 111, thereby internally short-circuiting the positive and negative electrodes of the battery monomer 10. The large instantaneous current generated by the internal short circuit can melt the electrical connection member inside the battery monomer 10, thereby cutting off the charging and discharging circuit of the battery monomer 10 and achieving overcharge protection. The melted electrical connection member can include the first adapter 121 and / or the second adapter 123. For example, the first adapter 121 has a first melting portion that melts when a large current passes through, thereby breaking the current path between the first tab 120 and the first electrode terminal 14.

[0173] In the above scheme, by providing the first deformation member 130, when the internal pressure of the battery monomer 10 reaches a certain level, for example, a first threshold value, the first deformation member 130 deforms to electrically connect the first electrode terminal 14, thereby internally short-circuiting the positive and negative electrodes of the battery monomer 10. The large instantaneous current generated by the internal short circuit can melt the electrical connection member inside the battery monomer 10, thereby cutting off the charging and discharging circuit of the battery monomer 10 and achieving overcharge protection. In addition, it can reduce the risk of thermal runaway of the battery monomer 10, thereby improving the reliability of the battery device.

[0174] According to some embodiments of the present application, referring to FIG. 10, the first electrode terminal 14 includes a first conductive member 140 and a first pole 141, the first conductive member 140 and the first pole 141 are connected to each other, the first conductive member 140 is disposed outside the first wall 111 and is insulated from the first wall 111, and the first pole 141 is electrically connected to the electrode assembly 12. The first deformation member 130 is configured to deform to contact the first conductive member 140 to electrically connect the first pole 141 and the first wall 111.

[0175] In some embodiments, the first electrode terminal 14 comprises a first conductive piece 140 and a first pole 141. The first conductive piece 140 is located on the side of the first wall 111 facing away from the electrode assembly 12, and is used to connect with an external busbar component (e.g. a tab). Exemplarily, the first conductive piece 140 is welded with the busbar component. The first pole 141 is connected with the first tab 120 of the electrode assembly 12, and is exemplarily connected with the first tab 120 through the first adapter 121. The first conductive piece 140 and the first pole 141 are connected with each other, and the connection relationship between the first conductive piece 140 and the first pole 141 comprises welding, riveting, screw connection or integral forming, etc. Exemplarily, in some embodiments, the first conductive piece 140 and the first pole 141 are riveted with each other, the first conductive piece 140 is generally plate-shaped, the first conductive piece 140 is formed with a riveting hole, the first pole 141 is generally columnar, e.g. cylindrical or polygonal columnar, etc., a part of the first pole 141 passes through the first through hole 1111 of the first wall 111 and is riveted in the riveting hole, and another part is located in the shell 11 and connected with the first tab 120 through the first adapter 121.

[0176] In some embodiments, an insulating structure is arranged between the first conductive piece 140 and the first wall 111. Exemplarily, the first conductive piece 140 and the first wall 111 are insulated from each other through a first insulating piece 150.

[0177] In some embodiments, the first wall 111 is formed with a first through hole 1111, and the first deformation piece 130 seals the first through hole 1111. When the internal pressure of the battery monomer 10 is at a certain degree, the first deformation piece 130 can be deformed to pass through the first through hole 1111 and contact the first conductive piece 140.

[0178] In the above scheme, by arranging the first conductive piece 140 on the outside of the first wall 111, on the one hand, it is convenient to connect with the external busbar component, and on the other hand, it is beneficial for the first deformation piece 130 to deform towards the outside under the action of the internal pressure to effectively conduct the first electrode terminal 14 and the first wall 111, thereby realizing overcharge protection and improving the reliability of the battery device.

[0179] According to some embodiments of the present application, the battery monomer 10 further comprises a first insulating piece 150, at least part of the first insulating piece 150 is arranged between the first conductive piece 140 and the first wall 111.

[0180] In some embodiments, the first insulating member 150 is arranged between the first conductive member 140 and the first wall 111, and is configured to insulate the first conductive member 140 from the first wall 111. In some embodiments, the first insulating member 150 can be made of a material with a high resistance value, such as an organic insulating material, an inorganic insulating material, or a hybrid insulating material. For example, in some embodiments of the present application, the first insulating member 150 can be made of an insulating PPS (polyphenylene sulfide) material. In other embodiments, the first insulating member 150 can also be made of polypropylene, polyethylene, or other materials with insulating properties.

[0181] In some embodiments, a portion of the first insulating member 150 can be arranged between the first wall 111 and the first conductive member 140, and another portion of the first insulating member 150 can be arranged around the outer circumferential surface of the first conductive member 140.

[0182] In some embodiments, the first wall 111 is formed with a first electrode lead-out hole 1110, the first electrode post 141 is arranged through the first electrode lead-out hole 1110, a portion of the first insulating member 150 can be arranged between the first wall 111 and the first conductive member 140, a portion of the first insulating member 150 can be arranged around the outer circumferential surface of the first conductive member 140, and another portion of the first insulating member 150 can be arranged in the first electrode lead-out hole 1110 and between the first electrode post 141 and the hole wall of the first electrode lead-out hole 1110.

[0183] In the above scheme, by arranging the first insulating member 150 between the first wall 111 and the first conductive member 140, the first wall 111 and the first conductive member 140 can be effectively insulated, and the risk of internal short circuit of the battery cell 10 caused by short circuit between the first wall 111 and the first conductive member 140 can be reduced, so that the reliability of the battery device is high. In particular, in an energy storage device with a high working voltage, by arranging the first insulating member 150 between the first wall 111 and the first conductive member 140, the risk of internal short circuit of the battery cell 10 caused by high-voltage electricity in the shell 11 due to out-of-control of the remaining battery cells 10 in the battery, which leads to conduction of the high-voltage electricity to the first wall 111 and the first conductive member 140, can be effectively reduced, so that the risk of thermal runaway of the energy storage device is reduced.

[0184] According to some embodiments of the present application, the first insulating member 150 has a resistance value greater than or equal to 200 megaohms.

[0185] In some embodiments, the first insulating member 150 with a resistance value greater than or equal to 200 megaohms can be arranged between the first wall 111 and the first conductive member 140. That is, in some embodiments, the first insulating member 150 can have a resistance value of 200 megaohms, 210 megaohms, 220 megaohms, or greater.

[0186] In some embodiments, the resistance value of the first insulating member 150 can be measured by a universal meter test method, a bridge measurement method, a voltammetry method, an ohmmeter method, or the like. In some embodiments, the resistance value of the first insulating member 150 can be measured by a megohmmeter.

[0187] In the above scheme, by setting the resistance value of the first insulating member 150 to be greater than or equal to 200 megaohms, the insulation withstand voltage between the first conductive member 140 and the first wall 111 can be effectively improved, the insulation withstand voltage requirement of the energy storage device can be effectively adapted, and the risk of the external voltage breaking through the first insulating member 150 to conduct the first wall 111 and the first conductive member 140, thereby causing internal short circuit of the battery monomer 10, can be reduced, so that the energy storage device has higher reliability.

[0188] According to some embodiments of the present application, please refer to FIG. 8 and FIG. 10. The first wall 111 has a first electrode lead-out hole 1110, and the first pole 141 passes through the first electrode lead-out hole 1110. The battery monomer 10 further comprises a second insulating member 151, at least part of the second insulating member 151 is arranged between the hole wall of the first electrode lead-out hole 1110 and the first pole 141.

[0189] The first electrode lead-out hole 1110 is a through-hole structure penetrating through the first wall 111. Part of the first pole 141 is located inside the first electrode lead-out hole 1110, part of the first pole 141 is located outside the first wall 111 to be connected with the first conductive member 140, and another part of the first pole 141 is located inside the first wall 111 to be connected with the first adapter 121.

[0190] The second insulating member 151 is used for insulating and isolating the first pole 141 and the first wall 111. “At least part of the second insulating member 151 is arranged between the hole wall of the first electrode lead-out hole 1110 and the first pole 141” can be understood as that the second insulating member 151 is arranged between the hole wall of the first electrode lead-out hole 1110 and the outer peripheral surface of the first pole 141, or part of the second insulating member 151 is arranged between the hole wall of the first electrode lead-out hole 1110 and the outer peripheral surface of the first pole 141, and another part of the second insulating member 151 is arranged between the inner side surface of the first wall 111 and the first pole 141.

[0191] In some embodiments, the second insulating member 151 can be made of a material with a relatively high resistance value, such as an organic insulating material, an inorganic insulating material, or a mixed insulating material, etc. For example, in some embodiments of the present application, the material of the second insulating member 151 can include an insulating PPS (polyphenylene sulfide) material. In other embodiments, the second insulating member 151 can also be made of other materials with insulating properties, such as polypropylene, polyethylene, etc.

[0192] In the above scheme, by arranging the second insulating member 151 between the hole wall of the first electrode lead-out hole 1110 and the first pole 141, the first wall 111 and the first pole 141 can be effectively insulated and isolated, and the risk of internal short circuit of the battery monomer 10 caused by short circuit between the first wall 111 and the first pole 141 is reduced, so that the reliability of the battery device is high.

[0193] According to some embodiments of the present application, the outer peripheral surface of the first pole 141 is formed with a first flange 1410, and part of the second insulating member 151 is located between the first flange 1410 and the inner side surface of the first wall 111 along the thickness direction z of the first wall.

[0194] The first flange 1410 is a component formed on the outer peripheral surface of the first pole 141. In some embodiments, the first flange 1410 can have a ring structure around the circumference of the first pole 141. In other embodiments, the first flange 1410 can also have a block structure, and the number of first flanges 1410 can be one or more. When there are multiple first flanges 1410, the multiple first flanges 1410 can be arranged at intervals around the circumference of the first pole 141. The circumference of the first pole 141 can be a direction perpendicular to the axial direction of the first pole 141.

[0195] "Part of the second insulating member 151 is located between the first flange 1410 and the inner side surface of the first wall 111 along the thickness direction z of the first wall" can be understood as that part of the second insulating member 151 is located between the side of the first flange 1410 facing the first wall 111 and the inner side surface of the first wall 111 along the thickness direction z of the first wall. In some embodiments, the projection of the second insulating member 151 along the thickness direction z of the first wall can cover the first flange 1410. In some embodiments, the projection of the first flange 1410 along the thickness direction z of the first wall can cover the projection of the second insulating member 151.

[0196] In the above scheme, by arranging part of the second insulating member 151 between the first flange 1410 and the inner side surface of the first wall 111, on the one hand, the first pole 141 and the first wall 111 can be effectively insulated and isolated, and on the other hand, the movement of the first pole 141 in the thickness direction z of the first wall can be limited, so that the first electrode terminal 14 is stably arranged on the first wall 111.

[0197] According to some embodiments of the present application, the resistance value of the second insulating member 151 is greater than or equal to 200 megaohms.

[0198] In some embodiments, a second insulating member 151 with a resistance value greater than or equal to 200 megaohms can be arranged between the first wall 111 and the first pole 141. That is, in some embodiments, the resistance value of the second insulating member 151 can be 200 megaohms, 210 megaohms, 220 megaohms or greater.

[0199] In some embodiments, the resistance value of the second insulating member 151 can be measured by a universal meter test method, a bridge measurement method, a voltammetry method, an ohmmeter method, or the like. In some embodiments, the resistance value of the second insulating member 151 can be measured by a megohmmeter.

[0200] In the above scheme, by setting the resistance value of the second insulating member 151 to be greater than or equal to 200 megaohms, the insulation withstand voltage between the first pole 141 and the first wall 111 can be effectively improved, the insulation withstand voltage requirement of the energy storage device can be effectively met, the risk of external voltage breaking through the second insulating member 151 to conduct the first wall 111 and the first pole 141, and causing internal short circuit of the battery monomer 10 can be reduced, and the energy storage device has higher reliability.

[0201] According to some embodiments of the present application, referring to FIG. 10, the surface of the first conductive member 140 facing the first wall 111 is provided with a first protrusion 1400, and the first protrusion 1400 is used to contact the first deformation member 130.

[0202] The first protrusion 1400 protrudes from the surface of the first conductive member 140 facing the first wall 111 in a direction from the outside of the first wall 111 to the inside of the first wall 111. In some embodiments, the surface of the first conductive member 140 facing the first wall 111 is the inner surface of the first conductive member 140, and the first protrusion 1400 can exceed the side of the first insulating member 150 in contact with the inner surface of the first conductive member 140 in the direction from the outside of the first wall 111 to the inside of the first wall 111.

[0203] The first protrusion 1400 is used to contact the first deformation member 130. For example, when the internal pressure of the battery monomer 10 is at a first degree, the first deformation member 130 deforms in a direction from the inside of the first wall 111 to the outside of the first wall 111 and contacts the first protrusion 1400, so that the first wall 111 is conducted with the first electrode terminal 14.

[0204] In the above scheme, by providing the first protrusion 1400 on the side of the first conductive member 140 facing the first wall 111, the stroke of the first deformation member 130 after deformation and contacting the first conductive member 140 can be shortened, the sensitivity and timeliness of overcharge protection can be effectively improved, and the reliability of the battery can be improved.

[0205] According to some embodiments of the present application, please refer to FIG. 11. The first deformation member 130 includes a first contact portion 1300, a first deformation portion 1301, and a first connecting portion 1302. The first deformation portion 1301 is arranged on the outer circumferential surface of the first contact portion 1300. The first connecting portion 1302 is arranged on the end of the first deformation portion 1301 away from the first contact portion 1300. The first connecting portion 1302 is connected with the first wall 111. The first deformation portion 1301 is configured to be deformable so as to make the first contact portion 1300 contact with the first conductive member 140.

[0206] In some embodiments, the first deformation member 130 can be a first flip sheet. The edge of the first flip sheet is welded with the first wall 111. The first flip sheet is flipped to contact with the first conductive member 140 under the pressure.

[0207] In some embodiments, please refer to FIG. 11. The first deformation member 130 can include, from inside to outside, the first contact portion 1300, the first deformation portion 1301, and the first connecting portion 1302. The first contact portion 1300 can be in a columnar shape. The first contact portion 1300 is used to contact with the first conductive member 140. The first deformation member 130 is connected with the outer circumferential surface of the first contact portion 1300. The first deformation portion 1301 can be in a foil sheet shape and extend around the circumference of the first contact portion 1300. The first connecting portion 1302 can be in a ring structure and arranged on the end of the first deformation portion 1301 away from the first contact portion 1300. The first connecting portion 1302 is connected with the first wall 111, for example, welded with the first wall 111.

[0208] In some embodiments, the projection of the first convex portion 1400 along the thickness direction z of the first wall can cover the projection of the first contact portion 1300. In some embodiments, the projection of the first convex portion 1400 along the thickness direction z of the first wall can coincide with the projection of the first contact portion 1300. In some embodiments, the projection of the first contact portion 1300 along the thickness direction z of the first wall can cover the projection of the first convex portion 1400.

[0209] In the above scheme, the first deformation member 130 has a simple structure and is easy to manufacture. The first deformation portion 1301 is deformed under stress to make the first contact portion 1300 act to contact the first conductive member 140. This can effectively play a role in overcharge protection, making the battery device have high reliability.

[0210] According to some embodiments of the present application, the maximum thickness of the first deformation portion 1301 is less than the maximum thickness of the first connecting portion 1302, and the maximum thickness of the first deformation portion 1301 is less than the maximum thickness of the first contact portion 1300.

[0211] In some embodiments, the maximum thickness of the first deformation portion 1301 can be less than the maximum thickness of the first connecting portion 1302, and can also be less than the maximum thickness of the first contact portion 1300.

[0212] Exemplarily, the cross section of the first connecting portion 1302 can be square, and the thickness of the first connecting portion 1302 can be the size of the cross section of the first connecting portion 1302 in the thickness direction z of the first wall. The thickness of the first contact portion 1300 can be the size of the first contact portion 1300 in the thickness direction z of the first wall.

[0213] In the above scheme, by setting the thickness of the first deformation portion 1301 to be small, when the internal pressure of the battery monomer 10 is at a certain degree, the first contact portion 1300 contacts the first conductive member 140 due to the deformation of the first deformation portion 1301, thereby timely and effectively achieving overcharge protection, and further improving the reliability of the battery device.

[0214] According to some embodiments of the present application, please refer to FIG. 8 and FIG. 12, FIG. 12 is a schematic view of the first wall 111, the second electrode terminal 16 and the second deformation member 131 in some embodiments of the present application.

[0215] The battery monomer 10 further comprises a second electrode terminal 16 and a second deformation member 131. The second electrode terminal 16 is insulatedly arranged on the first wall 111. The second deformation member 131 is electrically connected with the first wall 111, and the second deformation member 131 is configured to be deformable to electrically connect with the second electrode terminal 16.

[0216] In some embodiments, the deformation of the second deformation member 131 can directly or indirectly contact the second electrode terminal 16 to electrically connect with the second electrode terminal 16. Exemplarily, the "indirect contact" can be understood as that a conductive structure is arranged between the second deformation member 131 and the second electrode terminal 16, and when the internal pressure of the battery monomer 10 increases to a certain degree, the second deformation member 131 deforms to contact the conductive structure to electrically connect with the second electrode terminal 16.

[0217] In some embodiments, the battery cell 10 further comprises a second electrode terminal 16 electrically connected with the second tab 122 of the electrode assembly 12 for connecting with external busbar components. The polarity of the second electrode terminal 16 is opposite to that of the first electrode terminal 14, for example, the first electrode terminal 14 is a positive electrode terminal and the second electrode terminal 16 is a negative electrode terminal. The second electrode terminal 16 is used to electrically connect with the electrode assembly 12 for making current flow into or out of the second tab 122 through the second electrode terminal 16. In some embodiments, the second electrode terminal 16 is made of metal material, for example, made of aluminum, copper, iron, aluminum, steel, alloy or composite metal. In some embodiments, the second electrode terminal 16 can be connected with the second tab 122 through a second adapter 123.

[0218] In some embodiments, the second electrode terminal 16 comprises a second conductive piece 160 and a second pole 161. The second conductive piece 160 is located outside the first wall 111 and is used to connect with external busbar components (for example, a tab). In some embodiments, the first wall 111 is formed with a second electrode lead-out hole 1112, the second pole 161 passes through the second electrode lead-out hole 1112 and is connected with the second tab 122 through the second adapter 123. The second conductive piece 160 and the second pole 161 are connected with each other. The connection relationship between the second conductive piece 160 and the second pole 161 includes welding, riveting, threaded connection or integral forming, etc. For example, in some embodiments, the second conductive piece 160 and the second pole 161 are riveted with each other, the second conductive piece 160 is generally plate-shaped, the second conductive piece 160 is formed with a riveting hole, the second pole 161 is generally columnar, for example, cylindrical or polygonal columnar, etc., part of the second pole 161 passes through the second electrode lead-out hole 1112 of the first wall 111 and is riveted in the riveting hole, and the other part is located inside the shell 11 and is connected with the second tab 122 through the second adapter 123.

[0219] In some embodiments, a third insulating piece 152 is arranged between the second conductive piece 160 and the first wall 111 for insulating and isolating the second conductive piece 160 and the first wall 111. A fourth insulating piece 153 is arranged between the second pole 161 and the first wall 111, for example, the fourth insulating piece 153 is arranged between the outer periphery of the second pole 161 and the hole wall of the third through hole.

[0220] In some embodiments, the third insulation member 152 and / or the fourth insulation member 153 can be made of a material with a high resistance value, such as an organic insulation material, an inorganic insulation material, or a hybrid insulation material, etc. For example, in some embodiments of the present application, the material of the third insulation member 152 and / or the fourth insulation member 153 can include an insulation PPS (polyphenylene sulfide) material. In other embodiments, the third insulation member 152 and / or the fourth insulation member 153 can also be made of polypropylene, polyethylene, or other materials with insulation properties.

[0221] In some embodiments, the resistance value of the third insulation member 152 and / or the fourth insulation member 153 can be in units of mega-ohms (MΩ). For example, in some embodiments of the battery cell 10 provided by the present application, the resistance value of the third insulation member 152 and / or the fourth insulation member 153 can be greater than or equal to 200 MΩ.

[0222] In some embodiments, the second deformation member 131 is a short-circuit component. The second deformation member 131 is installed on the first wall 111, and the second deformation member 131 is electrically connected to the first wall 111. In some embodiments, the second deformation member 131 can be made of a metal material, for example, the second deformation member 131 is made of aluminum, copper, iron, aluminum, steel, an alloy, or a composite metal. In some embodiments, the second deformation member 131 can be welded to the inner side of the first wall 111. In some embodiments, the first wall 111 is formed with a second through hole 1113, and the second deformation member 131 closes the second through hole 1113.

[0223] The second deformation member 131 is a structural member that deforms under the internal pressure of the battery cell 10. The second deformation member 131 is used for overcharge protection of the battery cell 10. For example, when the battery cell 10 is in an abuse working condition such as overcharge, the internal pressure increases, and when the internal pressure reaches a certain level, for example, a second threshold value, the second deformation member 131 deforms to contact the second conductive member 160 through the second through hole 1113, thereby causing the second electrode terminal 16 and the first electrode terminal 14 to be electrically connected to each other through the first wall 111, so that the positive and negative electrodes inside the battery cell 10 are short-circuited.

[0224] In some embodiments, the second deformation member 131 can be a flip piece that flips under the action of pressure. Similar to the first deformation member 130 described above, the second deformation member 131 can include a second contact portion, a second deformation portion, and a second connection portion. The second deformation portion is arranged on the outer peripheral surface of the second contact portion, the second connection portion is arranged on the end portion of the second deformation portion away from the second contact portion, and the second connection portion is connected to the first wall 111. The first deformation portion 1301 is configured to be deformable to cause the second contact portion to contact the second conductive member 160.

[0225] In some embodiments, the second conductive member 160 is provided with a second protrusion 1600 facing the surface of the first wall 111, which is used to contact the second deformation member 131. In some embodiments, the projection of the second protrusion 1600 along the thickness direction z of the first wall can cover the projection of the second contact portion. In some embodiments, the projection of the second protrusion 1600 along the thickness direction z of the first wall can coincide with the projection of the second contact portion. In some embodiments, the projection of the second contact portion along the thickness direction z of the first wall can cover the projection of the second protrusion 1600.

[0226] In some embodiments, the first deformation member 130 deforms and releases the first conductive member 140 when the internal pressure of the battery cell 10 reaches a first threshold value, and the second deformation member 131 deforms and contacts the second conductive member 160 when the internal pressure of the battery cell 10 reaches a second threshold value. In some embodiments, the first threshold value and the second threshold value can be equal or not equal.

[0227] For example, when the battery cell 10 is in an abuse condition such as overcharge, the gas generating agent is decomposed, and the internal pressure of the battery cell 10 increases. When the internal pressure of the battery cell 10 reaches the first threshold value, the first deformation member 130 deforms to short the first electrode terminal 14 and the first wall 111. When the internal pressure of the battery cell 10 reaches the second threshold value, the second deformation member 131 deforms to short the second electrode terminal 16 and the first wall 111, so that the positive and negative electrodes inside the battery cell 10 are short-circuited to cause an internal short circuit. The large current generated instantaneously can melt the electrical connection member inside the battery cell 10, thereby cutting off the charging and discharging circuit of the battery cell 10, thereby playing a role of overcharge protection. The melted electrical connection member can include the first adapter 121 and / or the second adapter 123. For example, the first adapter 121 has a first melting portion, which can melt when a large current passes through, thereby breaking the current path of the first tab 120 and the first electrode terminal 14.

[0228] In the above scheme, by arranging the second deformation member 131, when the internal pressure of the battery monomer 10 reaches a certain degree, for example, the second threshold value, the second deformation member 131 deforms to be electrically connected with the second electrode terminal 16, so that the second electrode terminal 16 is electrically connected with the second wall, cooperating with the short circuit of the first deformation member 130 and the first electrode terminal 14, so that the electrical connection member inside the battery monomer 10 is fused due to the large current generated by the short circuit, so as to cut off the charging and discharging circuit of the battery monomer 10, thereby playing a role of overcharge protection, and reducing the risk of thermal runaway of the battery monomer 10, thereby making the battery device have higher reliability; on the other hand, because the first electrode terminal 14 and the second electrode terminal 16 are both insulated from the first wall 111 under normal working conditions, the shell 11 of the battery monomer 10 can be uncharged, which is beneficial to the energy storage device composed of the battery monomer 10, so that the risk of sparking breakdown between two adjacent battery monomers 10 in the energy storage device is small.

[0229] According to some embodiments of the present application, the second electrode terminal 16 is a negative electrode terminal, so that the minimum pressure value of the second deformation member 131 deforming is greater than the minimum pressure value of the first deformation member 130 deforming.

[0230] In some embodiments, the second electrode terminal 16 is a negative electrode terminal, that is, the second electrode terminal 16 is electrically connected with the negative electrode tab of the electrode assembly 12. When the internal pressure of the battery monomer 10 reaches the first threshold value, the first deformation member 130 deforms and contacts the first conductive member 140. When the internal pressure of the battery monomer 10 reaches the second threshold value and contacts the second conductive member 160, the second deformation member 131 deforms, and the second threshold value can be greater than the first threshold value.

[0231] The "second threshold value is greater than the first threshold value" can be understood as the second deformation member 131 is more difficult to deform than the first deformation member 130, that is, when the internal pressure of the battery monomer 10 further increases and exceeds the first threshold value, the second deformation member 131 deforms.

[0232] In some embodiments, the manufacturing material or structure of the second deformation member 131 can be changed to make the second deformation member 131 more difficult to deform than the first deformation member 130. For example, in some embodiments, the thickness of the second deformation part of the second deformation member 131 is greater than the thickness of the first deformation part 1301 of the first deformation member 130, so that the second deformation member 131 deforms to contact the second electrode terminal 16 only when it bears a larger pressure. Or, in some embodiments, a reinforcing structure, such as a reinforcing rib, a reinforcing concave-convex part, etc., is arranged on the second deformation part, so that the second deformation member 131 deforms to contact the second electrode terminal 16 only when it bears a larger pressure.

[0233] In some embodiments, the "second threshold value is greater than the first threshold value" can be understood as the second deformation member 131 needs to be in contact with the second electrode terminal 16 under the action of a greater pressure than the first deformation member 130, that is, when the internal pressure of the battery monomer 10 further increases and exceeds the first threshold value, the second deformation member 131 is in contact with the second electrode terminal 16. Illustratively, the distance between the second deformation member 131 and the second electrode terminal 16 can be increased, so that the second deformation member 131 needs to be deformed under the condition of a larger deformation amount to contact the second electrode terminal 16. For example, along the thickness direction z of the first wall, the distance between the second contact portion and the second electrode terminal 16 is greater than the distance between the first contact portion 1300 and the first electrode terminal 14.

[0234] In the above scheme, when the second electrode terminal 16 is a negative electrode terminal, by making the minimum pressure value for deforming the second deformation member 131 greater than the minimum pressure value for deforming the first deformation member 130, the second deformation member 131 can be deformed when the internal pressure of the battery monomer 10 is greater than the first deformation member 130. On the one hand, the battery monomer 10 can have an overcharge protection function, and on the other hand, the risk of the second deformation member 131 being turned over to cause the shell 11 to be negatively charged and corroded by the electrolyte due to gas production inside the battery monomer 10 under non-overcharge abuse conditions can be reduced, thereby ensuring the integrity of the shell 11 to some extent, reducing the risk of electrolyte leakage, and thus providing the reliability of the battery device.

[0235] According to some embodiments of the present application, a battery device is also provided, which has a plurality of battery monomers 10 described above. Referring to FIG. 3, the battery device 100 includes the battery monomer 10 and a box body, and the battery monomer 10 is contained in the box body. The box body is used to provide a containing space for the battery monomer 10, and the box body can adopt various structures.

[0236] In the battery device, the battery monomer 10 can be one or more, and each battery monomer 10 can be fixed to the box body by a connecting member (such as a bolt), or each battery monomer 10 can be fixed to the box body by an adhesive.

[0237] According to some embodiments of the present application, a battery device is also provided, which has a plurality of battery monomers 10 described above. Referring to FIG. 3, the battery device 100 includes the battery monomer 10 and a box body, and the battery monomer 10 is contained in the box body. The box body is used to provide a containing space for the battery monomer 10, and the box body can adopt various structures.

[0238] In some embodiments, the battery monomer 10 can first form a battery device, and one or more battery devices can be applied to an energy storage device. Referring to FIG. 2, the energy storage device 2000 can include a cabinet body 2001 and a plurality of battery devices 100. The plurality of battery devices 100 can be arranged in the cabinet body 2001. The plurality of battery devices 100 can be connected in series, in parallel, or in a hybrid manner.

[0239] According to some embodiments of the present application, the capacity of the battery cell 10 is greater than or equal to 280 Ah.

[0240] In some embodiments, the capacity of each battery cell 10 in the energy storage device 2000 can be greater than or equal to 280 Ah (ampere-hour). Exemplarily, in the energy storage device 2000, the capacity of the battery cell 10 can be selected from 280 Ah, 305 Ah, 306 Ah, 314 Ah, 315 Ah, 320 Ah, 325 Ah, 375 Ah, 560 Ah, 580 Ah, or other values greater than or equal to 280 Ah.

[0241] In the energy storage device 2000, by providing the battery cell 10 with the gas generating agent, when the energy storage device 2000 is in operation and charging the battery cell 10, timely and effective overcharge protection is achieved, the risk of thermal runaway of the battery cell 10 due to the decomposition of the main electrochemical substances of the battery cell 10 to generate a large amount of heat is reduced, and the risk of thermal runaway of the energy storage device 2000 is further reduced, so that the energy storage device 2000 has higher reliability.

[0242] According to some embodiments of the present application, a power utilization device is also provided, which includes the battery cell 10 described above. In some embodiments, the battery cell 10 is first configured into a battery device, and one or more battery devices are applied to the power utilization device.

[0243] In some embodiments, referring to FIG. 1, the power utilization device is a vehicle 1000. The interior of the vehicle 1000 can be provided with a controller 200, a motor 300, and a battery, and the controller 200 is used to control the battery device 100 to supply power to the motor 300.

[0244] Some embodiments of the present application provide a battery cell 10, please refer to FIG. 4-FIG. 12.

[0245] The battery cell 10 includes a housing 11, an electrode assembly 12, a first electrode terminal 14, a second electrode terminal 16, and an overcharge protection mechanism 13. The overcharge protection mechanism 13 can be a short-circuit component (SSD) or a circuit interrupting component (CID). Exemplarily, the overcharge protection mechanism 13 is a short-circuit component, which includes a first deformation member 130 and a second deformation member 131.

[0246] The housing 11 includes a shell 110 and a first wall 111. The first wall 111 is an end cover that closes the opening of the shell 110. In some embodiments, the first wall 111 can be made of an aluminum plate by stamping or milling processing, and the thickness of the cover plate is 2.0 mm. In some embodiments, the first wall 111 is provided with a pressure relief portion for relieving the pressure inside the battery cell 10. Exemplarily, the pressure relief portion is an explosion-proof valve provided on the end cover.

[0247] The first wall 111 is formed with a first through hole 1111, a first electrode lead-out hole 1110, a second through hole 1113 and a second electrode lead-out hole 1112. In some embodiments, the outer side surface of the first wall 111 can be milled to form a first sunken portion, the depth of the first sunken portion being 0.5 mm, and the first through hole 1111 and the first electrode lead-out hole 1110 being located in the first sunken portion. In some embodiments, the outer side surface of the first wall 111 can be milled to form a second sunken portion, the depth of the second sunken portion being 0.5 mm, and the second through hole 1113 and the second electrode lead-out hole 1112 being located in the first sunken portion. In some embodiments, the diameter of the first through hole 1111 can be 20 mm, and the diameter of the first electrode lead-out hole 1110 can be 10 mm.

[0248] The first electrode terminal 14, the first deformation piece 130, the second electrode terminal 16 and the second deformation piece 131 are mounted to the first wall 111. The first electrode terminal 14 includes a first conductive piece 140 arranged outside the first wall 111 and a first pole 141 electrically connected to the positive tab of the electrode assembly 12. A first insulating piece 150 is arranged between the first conductive piece 140 and the first wall 111, and a second insulating piece 151 is arranged between the first pole 141 and the first wall 111. The second electrode terminal 16 includes a second conductive piece 160 arranged outside the first wall 111 and a second pole 161 electrically connected to the negative tab of the electrode assembly 12. A third insulating piece 152 is arranged between the second conductive piece 160 and the first wall 111, and a fourth insulating piece 153 is arranged between the second pole 161 and the first wall 111.

[0249] In some embodiments, the length and width of the first insulating piece 150 can be equal to the length and width of the first sunken portion, the thickness of the first insulating piece 150 can be 2.7 mm, and the outer side surface of the first insulating piece 150 can be formed with a sunken portion by injection molding process, the depth of the sunken portion being 2.0 mm. The second insulating piece 151 can be in a cylindrical shape, the inner diameter thereof being 8 mm, the outer diameter thereof being 10 mm, and the height thereof being 3.0 mm. The length and width of the third insulating piece 152 can be equal to the length and width of the second sunken portion, the thickness of the third insulating piece 152 can be 2.7 mm, and the outer side surface of the third insulating piece 152 can be formed with a sunken portion by injection molding process, the depth of the sunken portion being 2.0 mm. The fourth insulating piece 153 can be in a cylindrical shape, the inner diameter thereof being 8 mm, the outer diameter thereof being 10 mm, and the height thereof being 3.0 mm.

[0250] In some embodiments, the first deformation member 130 is welded to the inner side of the first wall 111 and closes the first through hole 1111, and the second deformation member 131 is welded to the inner side of the first wall 111 and closes the second through hole 1113. The first deformation member 130 can be deformed to pass through the first through hole 1111 and contact the first conductive member 140, and the second deformation member 131 can be deformed to pass through the second through hole 1113 and contact the second conductive member 160. In some embodiments, the side of the first conductive member 140 facing the first wall 111 is provided with a first protrusion 1400 for contacting the first deformation member 130. The side of the second conductive member 160 facing the first wall 111 is provided with a second protrusion 1600 for contacting the second deformation member 131.

[0251] Exemplarily, the first deformation member 130 includes a first contact portion 1300, a first deformation portion 1301 provided on the outer circumferential surface of the first contact portion 1300, and a first connecting portion 1302 provided on the end of the first deformation portion 1301 away from the first contact portion 1300, and the first connecting portion 1302 is connected to the first wall 111. In some embodiments, the maximum thickness of the first connecting portion 1302 is 1.0 mm, the maximum thickness of the first deformation portion 1301 is 0.5 mm, the maximum thickness of the first contact portion 1300 is 2 mm, and the first contact portion 1300 is in a cylindrical shape with a circular cross section with a diameter of 7 mm.

[0252] Exemplarily, when the battery cell 10 is in an abuse condition such as overcharging, the internal pressure of the battery cell 10 increases. When the internal pressure of the battery cell 10 reaches a first threshold value, the first deformation member 130 deforms and contacts the first protrusion 1400. When the internal pressure of the battery cell 10 reaches a second threshold value, the second deformation member 131 deforms and contacts the second protrusion 1600, so that the positive and negative electrodes inside the battery cell 10 are short-circuited to cause an internal short circuit, and the large current generated instantaneously can melt the electrical connection member inside the battery cell 10, cutting off the charging and discharging circuit of the battery cell 10, thereby playing a role of overcharge protection.

[0253] To improve the timeliness of overcharge protection and make the overcharge protection mechanism 13 be triggered faster, the electrode assembly 12 in the battery cell 10 provided in some embodiments of the present application includes a gas generating agent. The gas generating agent is a voltage-sensitive gas generating agent configured to decompose and generate gas to trigger the overcharge protection mechanism 13. The gas generating agent is selected from at least one of carbonates, oxalates or chlorides. Exemplarily, the gas generating agent can be selected from lithium carbonate.

[0254] In some embodiments, the gas generating agent can be dispersed in the positive electrode sheet 124, coated on the surface of the positive electrode active material layer 1241, or coated on the surface of the positive electrode current collector 1240. When the gas generating agent can be dispersed in the positive electrode sheet 124, it can be understood that the gas generating agent is dispersed in the positive electrode active material layer 1241, and the mass percentage of the gas generating agent in the positive electrode active material layer 1241 is 0.1% to 10%, for example, the mass percentage of the gas generating agent in the positive electrode active material layer 1241 is 1%.

[0255] One or more embodiments will be described in more detail below with reference to the following examples. Of course, these examples do not limit the scope of one or more embodiments.

[0256] Comparative Examples and Examples

[0257] Example 1

[0258]

Preparation of the positive electrode sheet

[0259] The positive electrode active material lithium iron phosphate (LFP), the binder polyvinylidene fluoride (PVDF), the conductive agent Super P, and the gas generating agent lithium carbonate were added to the N-methyl pyrrolidone solvent in a mass ratio of 96:1.5:1.5:1.0, uniformly mixed to form a slurry, and then uniformly coated on the positive electrode current collector (aluminum foil). After drying, cold pressing, slitting, and laser cutting, the positive electrode sheet was formed. See Table 1 for details.

[0260]

Preparation of the negative electrode sheet

[0261] The negative electrode active material graphite, the binder styrene-butadiene rubber SBR and carboxymethyl cellulose CMC, and the conductive agent Super P were added to the deionized water in a mass ratio of 97:1:1:1, uniformly mixed to form a slurry, and then uniformly coated on the copper foil. After drying, cold pressing, slitting, and laser cutting, the second electrode sheet was formed.

[0262]

Separator

[0263] The separator was a polyethylene separator coated with a ceramic coating on both sides.

[0264]

Electrolyte

[0265] The lithium salt was lithium hexafluorophosphate, the solvent was a mixture of dimethyl carbonate, ethylene carbonate, and methyl ethyl carbonate, and the additive was vinylene carbonate.

[0266]

Short circuit protection mechanism

[0267] The short circuit protection mechanism included a short circuit component (SSD). See Table 1 for details.

[0268]

Battery assembly

[0269] The positive electrode sheet, the separator, the negative electrode sheet and the like are stacked in sequence to form an electrode assembly, the electrode assembly and the end cover are integrated by welding, and then are put into the shell made of aluminum. Finally, the target battery is manufactured after welding, adding electrolyte and other processes.

[0270] Example 2

[0271] The difference from Example 1 is that the content of the gas generating agent is different, as shown in Table 1.

[0272] Example 3

[0273] The difference from Example 1 is that the content of the gas generating agent is different, as shown in Table 1.

[0274] Example 4

[0275] The difference from Example 1 is that the content of the gas generating agent is different, as shown in Table 1.

[0276] Example 5

[0277] The difference from Example 1 is that the overcharge protection mechanism is different, and the overcharge protection mechanism includes a circuit interrupting device (CID). Details are shown in Table 1.

[0278] Example 6

[0279] The difference from Example 1 is in the preparation of the first electrode sheet, as follows:

[0280] The binder polyvinylidene fluoride (PVDF), the conductive agent Super P, and the gas generating agent lithium carbonate are added to the N-methyl pyrrolidone solvent in a mass ratio of 30:10:60, uniformly mixed to form a slurry, and then uniformly coated on the positive current collector (aluminum foil) with a coating thickness of 0.5 μm. After drying, a gas generating layer is formed. Then the positive active material lithium iron phosphate (LFP), the binder polyvinylidene fluoride (PVDF), and the conductive agent Super P are added to the N-methyl pyrrolidone solvent in a mass ratio of 97:1.5:1.5, uniformly mixed to form a slurry, and then uniformly coated on the gas generating layer. Finally, after drying, cold pressing, slitting, and laser cutting, the positive electrode sheet is formed.

[0281] Example 7

[0282] The difference from Example 1 is in the preparation of the first electrode sheet, as follows:

[0283] The positive active material lithium iron phosphate (LFP), the binder polyvinylidene fluoride (PVDF), and the conductive agent Super P are added to the N-methyl pyrrolidone solvent in a mass ratio of 97:1.5:1.5, uniformly mixed to form a slurry, and then uniformly coated on the aluminum foil. After drying, a positive active material layer is formed.

[0284] Then the binder polyvinylidene fluoride (PVDF), conductive agent Super P, and gas generator lithium carbonate are added into N-methyl pyrrolidone solvent in a mass ratio of 30:10:60, uniformly mixed to form a slurry, and then uniformly coated on the positive active material layer, with a coating thickness of 0.5 μm. Finally, after drying, cold pressing, slitting, and laser die cutting, the positive electrode sheet is formed.

[0285] Example 8

[0286] The difference from Example 1 is that the content of the gas generator is different, as shown in Table 1.

[0287] Example 9

[0288] The difference from Example 1 is that the same content of the gas generator as in Example 1 is used, and the slurry is coated on the positive current collector, as shown in Table 1.

[0289] Example 10

[0290] The difference from Example 1 is that the same content of the gas generator as in Example 1 is used, and the slurry is coated on the positive active material layer, as shown in Table 1.

[0291] Example 11

[0292] The difference from Example 1 is that 1.0% of an activator, which is Li2CO3, is added.

[0293] Comparative Example 1

[0294] The difference from Example 1 is that no overcharge protection mechanism is provided, and the battery monomer does not include a gas generator. Details are shown in Table 1.

[0295] Comparative Example 2

[0296] The difference from Example 1 is that the battery monomer does not include a gas generator. Details are shown in Table 1.

[0297]

Test Methods

[0298] 1. DCR test: The battery monomer is charged to the cut-off voltage at a current of 0.5 times the capacity value, and then charged at a constant voltage until the current is less than 0.05 times the capacity value, and then left for 1 h. Then, it is discharged at a constant current of 0.5 times the capacity value for 1 h, left for 2 h, and then discharged at a constant current of 4 times the capacity value for 30 s. The DCR is the voltage difference before and after discharging for 30 s divided by the current value.

[0299] 2. Voltage 0V time test and battery cell state test: overcharge test was performed on the full-charged experimental battery cell. The full-charged battery cell was overcharged to 1.5 times of the charging cut-off voltage of the battery cell or the charging time reached 1 h through constant current mode (the current was 0.5 times of the capacity value of the battery cell). The charging cut-off time and the final battery cell state were recorded.

[0300] The test results of each embodiment and each comparative example are shown in Table 1. Table 1

[0301] As can be seen from Table 1, the results of the voltage 0V time test and the battery cell state test of the battery cell provided by each embodiment are better than the results of the voltage 0V time test and the battery cell state test of the battery cell provided by the comparative example.

[0302] In Table 1, the "voltage 0V time" can be understood as the time when the battery cell charging and discharging loop is broken, or the time when the overcharge protection mechanism is triggered. The "battery cell state" can be understood as the state of whether the pressure relief valve of the battery cell is opened.

[0303] Through the data comparison of Examples 1 to 8 and Comparative Examples 1 and 2, it can be obtained that compared with the battery cell without the gas generating agent, the overcharge protection mechanism of the battery cell including the gas generating agent in the electrode assembly can be triggered in advance, the battery cell achieves overcharge protection, and the pressure relief valve is not opened, thereby reducing the risk of thermal runaway of the battery cell caused by the decomposition of the main electrochemical substances of the battery cell to generate a large amount of heat, and the reliability of the battery cell is high.

[0304] The smaller the DCR value, the better the charge and discharge capacity of the battery cell. Through the data comparison of Examples 1, 9 and 10, it can be obtained that the charge and discharge capacity of the battery cell with the gas generating agent dispersed in the active material layer is better than that of the battery cell with the gas generating agent arranged on the surface of the active material layer, and the charge and discharge capacity of the battery cell with the gas generating agent dispersed in the active material layer is better than that of the battery cell with the gas generating agent arranged on the surface of the positive current collector.

[0305] In some embodiments of the present application, through the data comparison of Examples 1 and 11, it can be obtained that the charge and discharge capacity of the battery cell with the gas generating agent dispersed in the active material layer is better than that of the battery cell with the gas generating agent and the activator (Li2CO3) dispersed in the active material layer, and the battery cell with the gas generating agent dispersed in the active material layer can more trigger the overcharge protection mechanism in advance, which is beneficial to the improvement of the reliability of the battery cell.

[0306] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

A battery cell, wherein, The battery cell of claim 1, wherein: the gas generating agent comprises at least one of a carbonate, an oxalate, or a chloride of lithium, sodium, potassium, magnesium, calcium, or aluminum. The battery cell of claim 1 or 2, wherein: the gas generating agent comprises at least one of lithium carbonate, lithium oxalate, or lithium chloride. The battery cell of any one of claims 1-3, wherein: the electrode assembly comprises a tab; the gas generating agent is disposed on the tab. The battery cell of claim 4, wherein: the tab comprises a cathode tab, and the gas generating agent is disposed on the cathode tab. The battery cell of claim 5, wherein: the cathode tab comprises a cathode current collector and a cathode active material layer coated on a surface of the cathode current collector, and the gas generating agent is disposed on the cathode active material layer. The battery cell of claim 6, wherein: the cathode active material layer comprises a cathode active material, a binder, a conductive agent, and the gas generating agent. The battery cell of claim 6 or 7, wherein: a mass percentage of the gas generating agent in the cathode active material layer is 0.1% to 10%. The battery cell of claim 8, wherein: a mass percentage of the gas generating agent in the cathode active material layer is 0.5% to 5.0%. The battery cell of claim 5, wherein: the cathode tab comprises a cathode current collector, a gas generating layer, and a cathode active material layer, the cathode active material layer is disposed between the cathode current collector and the gas generating layer, and the gas generating layer comprises the gas generating agent, a binder, and a conductive agent. The battery cell of claim 5, wherein: the cathode tab comprises a cathode current collector, a gas generating layer, and a cathode active material layer, the gas generating layer is disposed between the cathode current collector and the cathode active material layer, and the gas generating layer comprises the gas generating agent, a binder, and a conductive agent. The battery cell of any one of claims 1-11, wherein: the battery cell further comprises a first electrode terminal, and the first electrode terminal is insulated from the first wall; the overcharge protection mechanism comprises a first deformable member, the first deformable member is electrically connected to the first wall, and the first deformable member is configured to be deformable to electrically connect to the first electrode terminal. The battery cell of claim 12, wherein: the first electrode terminal comprises a first conductive member and a first pole, the first conductive member and the first pole are connected to each other, the first conductive member is disposed outside the first wall and insulated from the first wall, and the first pole is electrically connected to the electrode assembly; the first deformable member is configured to be deformable to contact the first conductive member to electrically connect the first pole to the first wall. The battery cell of claim 13, wherein: ​ ​ ​ ​ ​ The battery cell further includes a first insulating member, at least a portion of the first insulating member being disposed between the first conductive member and the first wall. The battery cell according to claim 14, wherein The first insulating member has an electrical resistance value of 200 mega ohms or more. The battery cell according to any one of claims 13-14, wherein The first wall has a first electrode lead hole through which the first pole passes; The battery cell further includes a second insulating member, at least a portion of the second insulating member being disposed between a hole wall of the first electrode lead hole and the first pole. The battery cell according to claim 16, wherein The first pole has a first flange formed on an outer circumferential surface thereof, and in a thickness direction of the first wall, a portion of the second insulating member is located between the first flange and an inner side surface of the first wall. The battery cell according to claim 16 or 17, wherein The second insulating member has an electrical resistance value of 200 mega ohms or more. The battery cell according to any one of claims 13-18, wherein A surface of the first conductive member facing the first wall is provided with a first protrusion for contacting the first deformation member. The battery cell according to any one of claims 13-19, wherein The first deformation member includes a first contact portion, a first deformation portion disposed on an outer circumferential surface of the first contact portion, and a first connection portion disposed on an end portion of the first deformation portion facing away from the first contact portion, the first connection portion being connected to the first wall, the first deformation portion being configured to be deformable to allow the first contact portion to contact the first conductive member. The battery cell according to claim 20, wherein A maximum thickness of the first deformation portion is less than a maximum thickness of the first connection portion, and the maximum thickness of the first deformation portion is less than a maximum thickness of the first contact portion. The battery cell according to any one of claims 12-21, wherein The battery cell further includes: a second electrode terminal insulated from the first wall; a second deformation member electrically connected to the first wall, the second deformation member being configured to be deformable to electrically connect to the second electrode terminal. The battery cell according to claim 22, wherein The second electrode terminal is a negative electrode terminal, such that a minimum pressure value at which the second deformation member is deformed is greater than a minimum pressure value at which the first deformation member is deformed. A battery device, wherein, A battery device including a plurality of battery cells according to any one of claims 1-23. An energy storage device, wherein, A battery device including a plurality of battery cells according to any one of claims 1-23, and / or the battery device according to claim 24. The energy storage device of claim 25, wherein, The battery cell has a capacity of 280 Ah or more. An electric power utilization device, wherein, A battery cell according to any one of claims 1-23 for providing electrical energy. A battery cell according to any one of claims 1-23 for providing electrical energy.

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