Battery monomer, battery device and electric device

Abstract

The utility model discloses a battery monomer, a battery device and a power utilization device. The battery cell comprises a shell, the shell is provided with an accommodating space, and the accommodating space accommodates an electrode assembly; the heating circuit is conductively connected with the electrode assembly, the heating circuit comprises at least one thermistor and at least one heating resistor which are connected in series, and the thermistor is contained in the containing space; the thermistor is configured so that the resistance value decreases as the temperature increases when the sensing temperature is between a first predetermined temperature threshold and a second predetermined temperature threshold, and the heating resistor is configured so as to be capable of heating when a current flows therethrough. The resistance value of the thermistor at the first preset temperature threshold value is 1 * 103 to 1 * 106 times of the resistance value of the thermistor at the second preset temperature threshold value. According to the application, under the condition that the sensed temperature rises to the preset temperature threshold value, rapid discharging can be realized through the heating circuit, so that the residual electric quantity of the single battery is reduced, and the risks of thermal runaway and thermal diffusion are reduced.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to battery cells, battery devices, and power-consuming devices. Background Technology

[0002] New energy batteries are being used more and more widely in daily life and industry. For example, new energy vehicles equipped with batteries are already widely used. In addition, batteries are being used more and more in the field of energy storage.

[0003] In battery-powered new energy vehicles, batteries can provide all or part of the power. In these applications, there is a risk of thermal runaway due to excessively high internal temperatures in individual battery cells. Therefore, reducing the risk of thermal runaway in individual battery cells is one of the key research topics in the industry. Utility Model Content

[0004] To address the aforementioned technical problems, this application provides a battery cell, a battery device, and an electrical device.

[0005] This application is achieved through the following technical solution.

[0006] A first aspect of this application provides a battery cell, the battery cell including a housing with a receiving space for accommodating an electrode assembly; and a heating circuit electrically connected to the electrode assembly. The heating circuit includes at least one thermistor and at least one heating resistor connected in series. The thermistor is housed in the receiving space, and the thermistor is configured such that its resistance decreases as the temperature increases when the sensed temperature is between a first predetermined temperature threshold and a second predetermined temperature threshold. The heating resistor is configured to generate heat when current flows through it. The second predetermined temperature threshold is higher than the first predetermined temperature threshold, and the resistance of the thermistor at the first predetermined temperature threshold is 1 to 10^3 to 10^6 times its resistance at the second predetermined temperature threshold.

[0007] Because the battery cell has an internal heating circuit, which includes a thermistor and a heating resistor connected in series, when the internal temperature of the battery cell gradually rises to the second predetermined temperature threshold, the resistance of the thermistor drops rapidly. The electrode assembly and the heating circuit form a conductive loop, and the external short circuit is quickly discharged through the heating circuit. This reduces the remaining charge of the battery cell, increases the thermal runaway critical temperature of the battery cell, reduces the risk of thermal runaway and thermal diffusion, and improves the reliability of the battery cell.

[0008] In addition, the heating resistor can dissipate the electrical energy of the battery cell by generating heat when the battery cell is discharging rapidly, which can further improve the discharge rate while avoiding the risk of local overheating.

[0009] Furthermore, the resistance of the thermistor decreases rapidly as the temperature rises, causing the current flowing through the heating circuit to gradually increase, which can reduce the charge of a single battery cell to a certain extent before reaching the second predetermined temperature threshold.

[0010] In some embodiments, the battery cell further includes an end cap, the housing has an opening, and the end cap is used to close the opening; the heating resistor includes a resistance wire connected to the end cap on the side of the end cap along the thickness direction near the electrode assembly.

[0011] Therefore, the resistance wire, acting as a load connected to the electrode assembly, can convert the electrical energy of the battery cells into heat energy, thereby increasing the discharge rate of the heating circuit. Furthermore, the connection between the resistance wire and the end cap allows heat generated inside the electrode assembly to be transferred to the end cap, reducing the risk of heat accumulation at the electrode assembly.

[0012] In some embodiments, the electrode assembly has a first surface, which is the plane with the largest area of ​​the electrode assembly, and the thermistor is disposed on the first surface.

[0013] As a result, the area of ​​the first surface is larger, which expands the selection of the thermistor's installation location, allowing for more flexible placement of the thermistor according to the internal structure of the battery cell.

[0014] In some embodiments, the thermistor is disposed at the center of the first surface.

[0015] Since the thermistor is located at the center of the first surface, it can more sensitively monitor the center that heats up faster when the temperature of the electrode assembly rises, thereby improving the sensitivity of the heating circuit and enabling it to respond to situations where the temperature exceeds the second predetermined temperature threshold in a timely and accurate manner, effectively reducing the risk of thermal runaway.

[0016] In some embodiments, the two first surfaces are located on opposite sides of the electrode assembly along a first direction, and the heating circuit includes a plurality of thermistors connected in series, the thermistors being disposed on at least one of the first surfaces.

[0017] Therefore, by adding thermistors, the flexibility of thermistor layout can be further improved. For example, the number and placement can be flexibly selected based on factors such as the shape of the electrode assembly and the arrangement of the battery cells. In addition, multiple thermistors can also expand the monitoring coverage, shorten the response time of the heating circuit, and improve the response speed.

[0018] In some embodiments, the battery cell is a cylindrical battery, and the thermistor is disposed on the cylindrical surface of the electrode assembly.

[0019] This expands the application scenarios of heating circuits, allowing them to be reused in more types of battery cells and improving their adaptability.

[0020] In some embodiments, the thermistor is a negative temperature coefficient thermistor.

[0021] Therefore, the resistance of the thermistor can decrease significantly as the temperature rises, and the current through the heating circuit gradually increases, thus gradually reducing the remaining charge.

[0022] In some embodiments, the thermistor is configured such that its resistance can drop below 0.01 ohms when the sensed temperature is not lower than the second predetermined temperature threshold.

[0023] Therefore, when the sensed temperature exceeds the second predetermined temperature threshold, the resistance of the thermistor becomes extremely small, further increasing the current flowing through the heating circuit. This allows for rapid discharge via an external short circuit, reducing the remaining charge of the battery cell.

[0024] In some embodiments,

[0025] When the sensed temperature is not lower than the second predetermined temperature threshold, the resistance R2 of the heating resistor is 2 to 10 times the total resistance R3 of the thermistor, and the resistance R2 of the heating resistor is not less than 0.02 ohms and not more than 0.1 ohms.

[0026] Therefore, the ratio of the resistance of the heating resistor to that of the thermistor is within a suitable range, which can prevent the temperature rise at the thermistor from being too high and affecting the state of the electrode assembly.

[0027] In some embodiments, the resistance R2 of the heating resistor is 3 to 5 times the total resistance R3 of the thermistor.

[0028] Therefore, by further controlling the resistance value of the heating resistor and the ratio of the thermistor to a suitable range, it is easier to accurately control the heat at the heating resistor and the thermistor, thereby improving the reliability of the heating circuit.

[0029] In some embodiments, the first predetermined temperature threshold is not higher than 25°C, and the second predetermined temperature threshold is not lower than 60°C and not higher than 150°C.

[0030] Since the first predetermined temperature threshold and the second predetermined temperature threshold are within a suitable range, the first predetermined temperature threshold and the second predetermined temperature threshold can be set according to factors such as the capacity, material, and structure of the battery cell, thus enabling the adaptation to more types of battery cells.

[0031] In some embodiments, the nominal voltage of the battery cell is in the range of 2.5V to 5V.

[0032] Therefore, it can be adapted to various thermal management solutions for battery cells, thereby improving the reliability of various battery cells.

[0033] In some embodiments, when the sensed temperature is below a second predetermined temperature threshold, the current flowing through the heating circuit does not exceed 10% of the self-discharge current of the battery cell.

[0034] Therefore, when the temperature is below the second predetermined temperature threshold, the resistance of the heating circuit can be adjusted to reduce the power loss caused by the heating circuit and extend the service life of the battery cell.

[0035] A second aspect of this application provides a battery device including a plurality of battery cells as described in the first aspect of this application.

[0036] Since the battery device includes the battery cell of the first aspect of the present application, the reliability of the battery device can be improved.

[0037] In some embodiments, a plurality of the battery cells are arranged with their large faces facing each other.

[0038] Therefore, during the thermal diffusion process of the battery device, the heat transferred from other battery cells can be transferred to the interior of battery cells that have not yet thermally runaway through a large area, causing the resistance of their thermistors to decrease, the heating circuit to discharge, and reducing the risk of thermal diffusion of the battery device.

[0039] A third aspect of this application provides an electrical device, including a battery cell as described in the first aspect of this application and a battery device as described in the second aspect of this application, wherein the battery cell or the battery device is used to store or provide electrical energy.

[0040] Since the power device includes a battery cell from the first aspect of the present application or a battery device from the second aspect of the present application, the reliability of the power device can be improved.

[0041] This application enables rapid discharge via a heating circuit when the internal temperature of a battery cell rises to a temperature threshold, thereby reducing the remaining charge of the battery cell, lowering the risk of thermal runaway and thermal diffusion, and improving the reliability of the battery cell. Attached Figure Description

[0042] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0043] Figure 1This application provides structural schematic diagrams of vehicles for some embodiments;

[0044] Figure 2 Exploded perspective view of a battery device provided for some embodiments of this application;

[0045] Figure 3 An exploded perspective view of a battery cell provided for some embodiments of this application;

[0046] Figure 4 Schematic diagrams of the structure of a battery cell provided for some embodiments of this application;

[0047] Figure 5 A schematic AA cross-sectional view of a battery cell provided for some embodiments of this application;

[0048] Figure 6 BB cross-sectional schematic diagram of a battery cell provided for some embodiments of this application;

[0049] Figure 7 A schematic AA cross-sectional view of a battery cell provided for other embodiments of this application;

[0050] Figure 8 The resistance-temperature diagram of a thermistor provided for some embodiments of this application.

[0051] Explanation of reference numerals in the attached figures

[0052] 1. Battery cell; 2. Housing; 3. Electrode assembly; 3A. First surface; 3B. Tab; 4. Heating circuit; 5. Thermistor; 6. Heating resistor; 7. End cap; 8. Electrode terminal; 100. Battery assembly; 101. Housing; 102. Cover; 103. Base plate; 200. Controller; 300. Motor; 1000. Vehicle. Detailed Implementation

[0053] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0054] 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 limit the application; the terms “comprising” and “having” and any variations thereof are intended to cover non-exclusive inclusion.

[0055] In the description of the embodiments of this application, technical terms such as "first," "second," and "third" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0056] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0057] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects are in an "or" relationship.

[0058] In the description of the embodiments of this application, the technical terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0059] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0060] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical term "contact" should be interpreted broadly, and can be direct contact, contact through an intermediate medium layer, contact between two contacting parties with substantially no interaction force, or contact between two contacting parties with interaction force.

[0061] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms "parallel" and "perpendicular" are both allowed to have a certain degree of tolerance and / or error, including cases of being approximately parallel and approximately perpendicular.

[0062] The following is a detailed description of this application.

[0063] Currently, new energy batteries are being used more and more widely in daily life and industry. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of power batteries, the market demand is also constantly increasing.

[0064] In many applications, there is a risk of thermal runaway due to excessively high internal temperatures in individual battery cells. This occurs when the internal temperature of a battery cell gradually rises, accumulating heat and eventually leading to irreversible thermal runaway. Furthermore, the heat generated can rapidly radiate to surrounding cells and be conducted to them, causing even more severe heat diffusion. Therefore, reducing the risk of thermal runaway in individual battery cells is a key research topic in the industry.

[0065] Through research and design, the resistance-temperature characteristics of the thermistor are utilized. When the internal temperature of a battery cell rises to a certain threshold, the resistance of the thermistor drops rapidly, causing the battery cell to short-circuit and discharge rapidly. This can increase the critical temperature for thermal runaway of the battery cell and reduce the risk of thermal runaway and thermal diffusion.

[0066] Based on this design concept, this application designs a battery cell, which includes a casing with a receiving space for accommodating an electrode assembly; a heating circuit electrically connected to the electrode assembly; and at least one thermistor and at least one heating resistor connected in series. The thermistor is housed within the receiving space, and its resistance decreases as the temperature increases when the sensed temperature is between a first predetermined temperature threshold and a second predetermined temperature threshold. The heating resistor is configured to generate heat when current flows through it. The second predetermined temperature threshold is higher than the first predetermined temperature threshold, and the resistance of the thermistor at the first predetermined temperature threshold is 1 to 10^3 to 10^6 times its resistance at the second predetermined temperature threshold.

[0067] Because the battery cell has an internal heating circuit, which includes a thermistor and a heating resistor connected in series, the thermistor's resistance rapidly decreases as the sensed temperature gradually rises to a second predetermined temperature threshold. This creates a conductive loop between the electrode assembly and the heating circuit, enabling rapid external short-circuit discharge. This reduces the remaining charge in the battery cell, raises its thermal runaway critical temperature, lowers the risk of thermal runaway and thermal propagation, and improves the battery cell's reliability. Furthermore, the heating resistor dissipates the battery cell's energy during rapid discharge, further increasing the discharge rate while preventing localized overheating.

[0068] In the following embodiments, for ease of explanation, a vehicle 1000 is used as an example of an electrical device according to an embodiment of this application. The description is as follows with reference to the accompanying drawings.

[0069] Figure 1 The diagram illustrates the structure of a vehicle 1000 as provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Figure 1 As shown, a battery device 100 is installed inside the vehicle 1000. The battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0070] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0071] Figure 2 This is an exploded perspective view of the battery device 100 provided in an embodiment of this application. Figure 2 As shown, the battery device 100 includes a base plate 103, a cover 102, and at least one battery cell 1. The cover 102 covers the base plate 103, thereby forming a space for accommodating the battery cell 1.

[0072] In the embodiments of this application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0073] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0074] Although not illustrated, a single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0075] In some embodiments, the electrode assembly has tabs (not shown) that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0076] In some embodiments, the electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0077] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0078] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0079] In some embodiments, such as Figure 3 As shown, the housing includes a shell 2 and an end cap 7. The shell 2 has an opening, and the end cap 7 closes the opening to form a sealed space for accommodating electrode components and electrolytes. The shell 2 may have one or more openings. The end cap 7 may also have one or more.

[0080] In some embodiments, the housing can be a sealed structure or a non-sealed structure. As an example, when the housing is a non-sealed structure, it serves to protect the electrode assembly, and a sealing bag is included between the housing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film. When the housing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0081] In some embodiments, such as Figure 3As shown, at least one electrode terminal 8 is provided on the outer casing, and the electrode terminal 8 is electrically connected to the tab 3B. The electrode terminal 8 can be directly connected to the tab 3B, or it can be indirectly connected to the tab 3B through a current collector (not shown). The electrode terminal 8 can be provided on the end cover 7, or it can be provided on the housing 2.

[0082] The emissions from battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of the separator, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0083] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0084] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0085] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0086] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing by fixing the battery module in the housing.

[0087] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0088] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0089] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0090] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0091] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0092] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0093] Below, refer to Figures 3 to 8 Some embodiments of this application will be described in detail.

[0094] Figure 3 An exploded perspective view of a battery cell provided for some embodiments of this application; Figure 4 Schematic diagrams of the structure of a battery cell provided for some embodiments of this application; Figure 5 A schematic AA cross-sectional view of a battery cell provided for some embodiments of this application; Figure 6 BB cross-sectional schematic diagram of a battery cell provided for some embodiments of this application; Figure 7 A schematic AA cross-sectional view of a battery cell provided for other embodiments of this application; Figure 8 The resistance-temperature diagram of a thermistor provided for some embodiments of this application.

[0095] In some embodiments of this application, for ease of explanation, a first direction, a second direction, and a third direction are defined. These directions intersect each other; intersecting includes perpendicularly intersecting. To facilitate understanding of the embodiments of this application, the embodiments shown in Figures 3 to 7 are illustrated using the example of the first direction, second direction, and third direction being perpendicularly intersecting. However, those skilled in the art should understand that the embodiments of this application are not limited to the case where these three directions intersect perpendicularly. For ease of explanation, as... Figure 3 As shown by the arrows in Figure 7, the direction of arrow Y is the first direction, the direction of arrow X is the second direction, and the direction of arrow Z is the third direction. Sometimes, the direction that arrow Z points to along the third direction is called "up," and its opposite direction is called "down."

[0096] The first aspect of this application provides a battery cell 1, such as... Figure 3As shown, the battery cell 1 includes a housing 2, which has a receiving space for accommodating an electrode assembly 3. The receiving space also accommodates a heating circuit 4, which is electrically connected to the electrode assembly 3. The heating circuit 4 includes at least one thermistor 5 and at least one heating resistor 6 connected in series. The thermistor 5 is configured to decrease its resistance as the temperature increases when the sensed temperature is between a first predetermined temperature threshold and a second predetermined temperature threshold. The heating resistor 6 is configured to generate heat when current flows through it. The second predetermined temperature threshold is higher than the first predetermined temperature threshold, and the resistance of the thermistor 5 at the first predetermined temperature threshold is 1*10^3 times to 1*10^6 times its resistance at the second predetermined temperature threshold.

[0097] It is understood that the housing 2 can be used to accommodate the electrode assembly 3, the electrolyte (not shown in the figure), and other components.

[0098] Optionally, the material of the shell 2 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not limit this.

[0099] Optionally, the housing 2 can be of various shapes and sizes. The shape of the housing 2 can be a cylinder, cuboid, polygonal prism, or other shapes, such as a hexagonal prism. It is understood that the shape of the housing 2 can be determined based on the specific shape and size of the electrode assembly 3. For example, if the electrode assembly 3 has a cylindrical structure, a cylindrical housing 2 can be used; if the electrode assembly 3 has a cuboid structure, a cuboid housing 2 can be used.

[0100] Electrode assembly 3 is the component in the battery cell 1 where the electrochemical reaction takes place. The housing 2 may contain one or more electrode assemblies 3. Electrode assembly 3 may have tabs 3B.

[0101] Optionally, the rise in sensing temperature can be caused by mechanical, electrical, or thermal abuse factors, and can occur during charging or discharging.

[0102] For example, the heating circuit 4 can be electrically connected to the tab 3B to form a circuit.

[0103] The thermistor 5 is a thermal element whose resistance changes with temperature, exhibiting high sensitivity, fast response, and good stability. When the sensed temperature is between a first predetermined temperature threshold and a second predetermined temperature threshold, the resistance decreases as the temperature increases; that is, the resistance of the thermistor 5 is negatively correlated with temperature. The thermistor 5 is a semiconductor ceramic made of two or more metal oxides such as manganese, copper, silicon, cobalt, iron, nickel, and zinc. The specific material of the thermistor 5 is not limited in this application embodiment.

[0104] For example, the sensed temperature can be the internal ambient temperature of the battery cell 1 sensed by the thermistor 5.

[0105] In a specific embodiment, such as Figure 8 As shown, the thermistor 5 has a high resistance at low temperatures, and its resistance gradually decreases as the temperature rises. At room temperature (25 degrees Celsius), the thermistor 5 has a high resistance. Taking the lithium battery cell 1 as an example, the current flowing through the heating circuit 4 is very small at this time. However, when the sensing temperature reaches or exceeds 60°C, the thermistor 5 drops to 0.01 ohms or below, causing the current flowing through the heating circuit 4 to increase rapidly. This discharges through the heating circuit 4, reducing the remaining charge and SOC (state of charge) of the battery cell 1, increasing the thermal runaway critical temperature of the battery cell 1, and reducing the risk and adverse effects of thermal runaway.

[0106] Optionally, a thermistor 5 can be installed inside the battery cell 1, or multiple thermistors 5 can be installed, and the multiple thermistors 5 are connected in series.

[0107] Optionally, the heating resistor 6 can be a resistance wire, an electrothermal film, or a semiconductor device, which generates heat when current flows through it, converting electrical energy into heat energy, and further consuming the remaining power of the battery cell 1 when a large current flows through the heating circuit 4.

[0108] Because the battery cell 1 is equipped with a heating circuit 4, which includes a thermistor 5 and a heating resistor 6 connected in series, the resistance of the thermistor 5 decreases rapidly as the internal temperature of the battery cell 1 gradually increases. The electrode assembly 3 and the heating circuit 4 form a conductive loop, and the external short circuit is quickly discharged through the heating circuit 4, which reduces the remaining charge of the battery cell 1, increases the thermal runaway critical temperature of the battery cell 1, reduces the risk of thermal runaway and thermal diffusion, and improves the reliability of the battery cell 1.

[0109] In addition, the heating resistor 6 can dissipate the electrical energy of the battery cell 1 by generating heat when the battery cell 1 is discharging rapidly, which can further improve the discharge rate while avoiding the risk of local overheating.

[0110] In the embodiments of this application, the second predetermined temperature threshold is higher than the first predetermined temperature threshold, and the resistance of the thermistor at the first predetermined temperature threshold is 1*10^3 times to 1*10^6 times the resistance at the second predetermined temperature threshold.

[0111] In a specific embodiment, such as Figure 8 As shown, the first predetermined temperature threshold can be 25℃, and the second predetermined temperature threshold can be 60℃. At room temperature (25℃), the thermistor 5 has a resistance of 10kΩ, but when the temperature is not lower than 60℃, the resistance of the thermistor 5 drops to 0.01Ω, which is a factor of 1*10^6.

[0112] As a result, the resistance of the thermistor 5 decreases rapidly when the temperature rises, causing the current flowing through the heating circuit 4 to gradually increase, which can reduce the charge of the battery cell 1 to a certain extent before reaching the second predetermined temperature threshold.

[0113] In the embodiments of this application, the first predetermined temperature threshold is not higher than 25°C, and the second predetermined temperature threshold is not lower than 60°C and not higher than 150°C.

[0114] It is understandable that the first and second predetermined temperature thresholds can be adjusted based on factors such as thermal management requirements and the capacity of the battery cell 1.

[0115] For example, the second predetermined temperature threshold may be 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, etc. Other values ​​will not be listed.

[0116] Since the first predetermined temperature threshold and the second predetermined temperature threshold are within a suitable range, the first predetermined temperature threshold and the second predetermined temperature threshold can be set according to factors such as the capacity, material, and structure of the battery cell 1, thus enabling the adaptation to more types of battery cells 1.

[0117] In the embodiments of this application, the thermistor 5 is a negative temperature coefficient thermistor.

[0118] For example, such as Figure 8 As shown, the resistance of a negative temperature coefficient (NTC) thermistor decreases significantly with increasing temperature.

[0119] Therefore, the resistance of thermistor 5 can decrease significantly as the temperature rises, and the current through the heating circuit gradually increases, thus gradually reducing the remaining charge.

[0120] In embodiments of this application, the thermistor 5 is configured such that its resistance can drop below 0.01 ohms when the sensed temperature is not lower than a second predetermined temperature threshold.

[0121] For example, such as Figure 8 As shown, the second predetermined temperature threshold is 60°C, and the resistance of the thermistor 5 is 0.01Ω.

[0122] Therefore, when the sensed temperature exceeds the second predetermined temperature threshold, the resistance of the thermistor 5 becomes extremely small, further increasing the current flowing through the heating circuit 4, thereby achieving rapid discharge through the external short circuit and reducing the remaining charge of the battery cell 1.

[0123] In the embodiments of this application, the battery cell 1 further includes an end cap 7, the housing 2 has an opening, and the end cap 7 is used to close the opening; the heating resistor 6 includes a resistance wire, which is connected to the side of the end cap 7 along the thickness direction near the electrode assembly 3.

[0124] In a specific embodiment, the thickness direction of the end cap 7 can be a third direction (Z).

[0125] Optionally, the housing 2 and the end cap 7 can be separate components. An opening can be provided on the housing 2, and the end cap 7 can be used to close the opening to form a space for receiving the battery cell 1.

[0126] Alternatively, the end cap 7 and the housing 2 can be integrated. Specifically, the end cap 7 and the housing 2 can form a common connection surface before other components are installed in the housing. When it is necessary to encapsulate the interior of the housing 2, the end cap 7 can then cover the housing 2.

[0127] For example, the end cap 7 and the housing 2 are independent components. The end cap 7 can be fixed to the housing 2 by welding and close the opening of the housing 2.

[0128] For example, the end cap 7 is provided with an electrode terminal 8, which can be electrically connected to the electrode assembly 3 to output electrical energy of the battery cell 1 or input electrical energy to the battery cell 1.

[0129] Optionally, the electrode terminal 8 is electrically connected to the tab 3B of the electrode assembly 3. This connection can be either a direct connection between the electrode terminal 8 and the tab 3B, or a connection between the electrode terminal 8 and the tab 3B via an adapter. This application does not limit the specific connection in this embodiment.

[0130] Optionally, the electrode terminal 8 can be made of one metal material or multiple metal materials, including but not limited to copper, aluminum, nickel, zinc, and iron. Alternatively, the electrode terminal 8 can be a single-piece molded component or composed of multiple separately molded parts connected together.

[0131] It is understood that a resistance wire is a component that generates heat through an electric current. When current passes through the resistance wire, electrical energy is converted into heat energy due to the resistance. This application does not limit the shape or material of the resistance wire.

[0132] For example, the resistance wire can be insulatedly connected to the end cap 7 by means of bonding or other methods.

[0133] For example, such as Figure 6 As shown, the resistance wire can be bonded to the weld between the end cap 7 and the housing 2. This ensures that the position of the resistance wire does not affect the flow of the electrolyte or interfere with other structures. Even when the resistance wire generates a high amount of heat, it will not cause side reactions in the electrolyte. Furthermore, the weld can absorb some of the generated heat.

[0134] In a specific embodiment, the electrode assembly 3 has two tabs 3B. For example... Figure 5 , Figure 7 As shown, along the second direction (X), the resistance wire can be positioned between the two tabs 3B without contacting them, reducing the risk of normal short circuit. The second direction (X) can be perpendicular to both the first direction (Y) and the third direction (Z).

[0135] Therefore, the resistance wire, as a load connected to the electrode assembly 3, can convert the electrical energy of the battery cell 1 into heat energy, thereby increasing the discharge rate of the heating circuit 4. In addition, the resistance wire is connected to the end cap 7, which can transfer the heat originally generated inside the electrode assembly 3 to the end cap 7, reducing the risk of heat accumulation at the electrode assembly 3.

[0136] In the embodiments of this application, such as Figure 3 As shown, the electrode assembly 3 has a first surface 3A, which is the plane with the largest area of ​​the electrode assembly 3, and the thermistor 5 is disposed on the first surface 3A.

[0137] Optionally, the electrode assembly 3 may have one or more first surfaces 3A.

[0138] Optionally, the thermistor 5 can be designed as a sheet structure to facilitate bonding to the first surface 3A.

[0139] Optionally, the thermistor 5 can be disposed on the first surface 3A by means of bonding or other methods.

[0140] For example, the thermistor 5 can be bonded to the first surface 3A using thermally conductive adhesive. The thermally conductive adhesive has good thermal conductivity and insulation properties, which is beneficial for the thermistor 5 to monitor the temperature of the electrode assembly 3.

[0141] As another example, the thermistor 5 can be adhered to the insulating film covering the electrode assembly 3, and the insulating film can be a Mylar film.

[0142] In a specific embodiment, such as Figure 4 , Figure 5 , Figure 6 As shown, the battery cell 1 is a prismatic battery, and the electrode assembly 3 is approximately a cuboid. Along the first direction (Y), the large surface of the battery cell 1 is positioned opposite to the first surface 3A of the electrode assembly 3.

[0143] As a result, the area of ​​the first surface 3A is larger, which expands the selection of the mounting position of the thermistor 5, and the thermistor 5 can be set more flexibly according to the internal structure of the battery cell 1.

[0144] In an embodiment of this application, the thermistor 5 is disposed at the center of the first surface 3A.

[0145] It is understandable that the center refers to the geometric center of the first surface 3A.

[0146] Since the thermistor 5 is located at the center of the first surface 3A, it can more sensitively monitor the area that heats up faster when the temperature of the electrode assembly 3 rises, thereby improving the sensitivity of the heating circuit 4 and enabling it to respond to the situation where the temperature exceeds the second predetermined temperature threshold in a timely and accurate manner, thus effectively reducing the risk of thermal runaway.

[0147] In the embodiments of this application, such as Figure 6 As shown, two first surfaces 3A are located on both sides of the electrode assembly 3 along the first direction (Y), and the heating circuit 4 includes a plurality of thermistors 5 connected in series, with the thermistors 5 disposed on at least one first surface 3A.

[0148] Optionally, multiple thermistors 5 can be disposed on the same first surface 3A, or they can be disposed on different first surfaces 3A.

[0149] For example, such as Figure 7 As shown, four thermistors 5 can be disposed on the same first surface 3A. The first surface 3A is approximately quadrilateral, and the thermistors 5 can be distributed and disposed in the edge region of the first surface 3A.

[0150] For example, such as Figure 6 As shown, the two thermistors 5 can be disposed on different first surfaces 3A. The thermistors 5 can be disposed at the center of each first surface 3A.

[0151] It is understood that the number and installation position of the thermistors 5 in the embodiments of this application can be adjusted according to the shape, size and thermal management requirements of the electrode assembly 3, and are not limited to the embodiments shown in the figure.

[0152] Therefore, by adding thermistors 5, the flexibility of the thermistor layout can be further improved. For example, the number and placement can be flexibly selected based on factors such as the shape of the electrode assembly 3 and the arrangement of the battery cells 1. In addition, multiple thermistors 5 can also expand the monitoring coverage of the thermistors 5, shorten the response time of the heating circuit 4, and improve the response speed.

[0153] In the embodiments of this application, the battery cell 1 is a cylindrical battery, and the thermistor 5 is disposed on the cylindrical surface of the electrode assembly 3.

[0154] It is understandable that the electrode assembly 3 of the cylindrical battery is approximately cylindrical, and the thermistor 5 can be disposed on the outer side of the cylindrical surface of the electrode assembly 3.

[0155] This expands the application scenarios of the heating circuit 4, allowing it to be reused in more types of battery cells 1, thus improving the adaptability of the heating circuit 4.

[0156] In the embodiments of this application, when the sensed temperature is not lower than the second predetermined temperature threshold, the total resistance R1 of the heating circuit 4 satisfies: R1=U / (X / n).

[0157] in:

[0158] U is the nominal voltage of battery cell 1;

[0159] X represents the nominal capacity of battery cell 1; the unit is ampere-hour (Ah).

[0160] n is the number of hours that battery cell 1 discharges its nominal capacity;

[0161] In the embodiments of this application, when the sensed temperature is not lower than the second predetermined temperature threshold, the resistance R2 of the heating resistor 6 is 2 to 10 times the total resistance R3 of the thermistor 5, and the resistance R2 of the heating resistor 6 is not lower than 0.02 ohms and not higher than 0.1 ohms.

[0162] Optionally, if the sensed temperature is not lower than the second predetermined temperature threshold, R2 can be 2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, 6 times, 6.5 times, 7 times, 7.5 times, 8 times, 8.5 times, 9 times, 9.5 times, 10 times, etc., of R3, and other values ​​will not be listed.

[0163] Optionally, the resistance value R2 of the heating resistor 6 can be 0.02 ohms, 0.03 ohms, 0.04 ohms, 0.05 ohms, 0.06 ohms, 0.07 ohms, 0.08 ohms, 0.09 ohms, 0.1 ohms, etc. Other values ​​will not be listed.

[0164] Therefore, the resistance ratio is within a suitable range, which can prevent the temperature rise at the thermistor 5 from being too high and affecting the state of the electrode assembly 3.

[0165] Furthermore, when the sensed temperature is not lower than the second predetermined temperature threshold, the resistance R2 of the heating resistor 6 is 3 to 5 times the total resistance R3 of the thermistor 5.

[0166] For example, the thermistor 5 is connected in series with the heating resistor 6, and the total resistance R1 of the heating circuit 4 satisfies R1=R2+R3.

[0167] For example, the number of thermistors 5 is one, and R3 is the resistance value of a single thermistor 5.

[0168] As another example, there are multiple thermistors 5, which are connected in series, and R3 is the total resistance of the multiple thermistors 5 connected in series.

[0169] For example, the heating resistor 6 is a resistance wire, and the resistance value R2 of the heating resistor 6 is the resistance of the resistance wire.

[0170] In a specific embodiment, assuming the capacity of battery cell 1 is X amp-hours, the nominal voltage is 4.25V, and it is set to discharge completely in n hours, then the resistance R1 of the heating circuit 4 is 4.25 / (X / n). When R2 / R3 = 4:1, we can obtain R2 = R1 * 0.8, R3 = R1 * 0.2. The discharge time n can be adjusted according to thermal management requirements.

[0171] Therefore, the resistance of the heating circuit 4 can be adjusted according to the capacity and the predetermined discharge time to achieve rapid discharge, matching the capacity of the battery device 100 and improving the flexibility of discharge control. In addition, by further controlling the ratio of the resistance of the heating resistor 6 to the thermistor 5 within an appropriate range, it is easier to accurately control the heat at the heating resistor 6 and the thermistor 5, thereby improving the reliability of the heating circuit 4.

[0172] In some embodiments, the nominal voltage of the battery cell 1 is in the range of 2.5V to 5V.

[0173] For example, the nominal voltage can be 2.5V, 2.6V, 2.7V, 2.8V, 2.9V, 3.0V, 3.1V, 3.2V, 3.3V, 3.4V, 3.5V, 3.6V, 3.7V, 3.8V, 3.9V, 4.0V, 4.1V, 4.2V, 4.3V, 4.4V, 4.5V, 4.6V, 4.7V, 4.8V, 4.9V, or 5.0V. Other values ​​are not listed.

[0174] Therefore, it can be adapted to various thermal management schemes of battery cells 1, thereby improving the reliability of various battery cells 1.

[0175] In the embodiments of this application, when the sensed temperature is lower than the second predetermined temperature threshold, the current flowing through the heating circuit 4 does not exceed 10% of the self-discharge current of the battery cell 1.

[0176] Self-discharge of battery cell 1 refers to the phenomenon that battery cell 1 gradually reduces its charge due to internal chemical reactions when there is no external load.

[0177] For example, when the sensed temperature is below the second predetermined temperature threshold, that is, when the battery cell 1 is in normal condition, the current flowing through the heating circuit 4 can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% of the self-discharge current of the battery cell 1, etc. Other values ​​will not be listed.

[0178] Therefore, when the temperature is below the second predetermined temperature threshold, the resistance of the heating circuit 4 can be adjusted to reduce the power loss caused by the heating circuit 4 and extend the service life of the battery cell 1.

[0179] A second aspect of this application provides a battery device 100, including a plurality of battery cells 1 according to the first aspect of this application.

[0180] In a specific embodiment, such as Figure 2 As shown, the battery device 100 includes a housing 101 and a plurality of battery cells 1. The housing 101 includes a base plate 103 and a cover 102. The cover 102 covers the base plate 103 and can be fastened to the base plate 103 to form a sealed space to accommodate the battery cells 1.

[0181] Optionally, the individual battery cells 1 can be assembled into modules and housed in the housing 101.

[0182] Since the battery device 100 includes the battery cell 1 of the first aspect of the present application embodiment, the reliability of the battery device 100 can be improved.

[0183] In the embodiments of this application, such as Figure 2 As shown, multiple battery cells 1 are arranged with their large faces facing each other.

[0184] Therefore, during the thermal diffusion process of the battery device 100, the heat transferred from other battery cells 1 can be transferred to the interior of the battery cells 1 that have not yet thermally runaway through a large surface area, causing the resistance of the thermistor 5 to decrease, the heating circuit 4 to discharge, and reducing the risk of thermal diffusion of the battery device 100.

[0185] A third aspect of the present application provides an electrical device, including a battery cell 1 of the first aspect of the present application or a battery device 100 of the second aspect of the present application, wherein the battery cell 1 or the battery device 100 is used to store or provide electrical energy.

[0186] In a specific embodiment, such as Figure 1 As shown, the electrical device can be a vehicle 1000, and a battery device 100 is installed inside the vehicle 1000. The battery device 100 can be used to power the vehicle 1000.

[0187] Since the power device includes the battery cell 1 of the first aspect of the present application embodiment or the battery device 100 of the second aspect of the present application embodiment, the reliability of the power device can be improved.

[0188] The specific embodiments are described in detail below with reference to the accompanying drawings.

[0189] In this embodiment, a heating circuit 4 is installed inside the battery cell 1. When the internal temperature of the battery cell 1 begins to rise, the resistance of the thermistor 5 in the heating circuit 4 drops rapidly, and the heating circuit 4 discharges. The energy in the battery cell 1 is released as heat to the end cap 7 through the heating resistor 6 in the heating circuit 4, which prevents heat from accumulating at the electrode assembly 3. At the same time, as the SOC of the battery cell 1 decreases, the thermal runaway boundary of the battery cell 1 is raised, thereby avoiding the risk of thermal runaway or reducing the consequences of thermal runaway.

[0190] In addition, during high-temperature cycling of battery cell 1, this embodiment can prevent the battery cell 1 from overheating during fast charging. After the battery cell 1 is heated to a certain temperature during fast charging, it can be discharged, thereby avoiding the side reaction caused by excessive temperature leading to thermal runaway.

[0191] For example, such as Figure 5 , Figure 6 , Figure 7 As shown, the heating resistor 6 is a resistance wire. This resistance wire can be arranged inside the battery cell 1 at a position away from the electrode assembly 3 without affecting the internal structure of the battery cell 1. The thermistor 5 is generally arranged on the outside of the Mylar film of the electrode assembly 3.

[0192] Optionally, the resistance of the thermistor 5 decreases rapidly over a temperature range of 60-150℃. The heating circuit 4 can handle currents generally above 1C, and the heating power of the resistance wire is generally within 1H, which can reduce the SOC of the battery cell 1 to 0%.

[0193] For example, the resistance wire is integrated on the end cap 7, which does not affect the flow of electrolyte and will not cause side reactions in the electrolyte when the heat generation is high.

[0194] For example, the resistance wire can be fixed near the weld of the end cap 7 with ceramic glue, and the wire connecting the heating circuit 4 can withstand a current of 120A when different components are connected in series.

[0195] In a specific embodiment, the resistance of the thermistor 5 rapidly decreases to below 0.01Ω at 60℃ (i.e., the second predetermined temperature threshold), and is above 10kΩ at room temperature (25℃, the first predetermined temperature threshold); the resistance of the heating resistor 6 is 0.03Ω. Calculated with the voltage of battery cell 1 being 4.25V, the total resistance R1 of the heating circuit 4 is approximately 0.04Ω, and the line current is 106A. When the heating resistor 6 heats up, the SOC of battery cell 1 drops rapidly, and the probability of thermal runaway of battery cell 1 decreases.

[0196] During the thermal runaway of a single battery cell 1, the heat generated inside the electrode assembly 3 is transferred to the end cap 7 by the heating resistor 6. The heat cannot accumulate inside the battery cell 1 or at the electrode assembly 3, which reduces the risk of thermal runaway of a single battery cell 1 and also reduces the risk of thermal diffusion.

[0197] During the thermal diffusion process of the system, the heat transferred from the adjacent trigger battery cell 1 causes the internal temperature of battery cell 1 to rise, the resistance of the thermistor 5 to decrease, and the heating resistor 6 converts the energy of battery cell 1 into heat, thereby increasing the thermal runaway temperature of battery cell 1 and reducing the thermal diffusion risk of battery cell 1.

[0198] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0199] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0200] The above embodiments are merely illustrative of the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and all should be covered within the scope of protection claimed in this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of protection claimed.

Claims

1. A battery cell, characterized in that: include: A housing, wherein the housing is formed with a receiving space, and the receiving space receives the electrode assembly; a heating circuit, the heating circuit being conductively connected to the electrode assembly, The heating circuit comprises at least one thermistor and at least one heating resistor connected in series, the thermistor is accommodated in the accommodation space, and the thermistor is configured to decrease the resistance value as the temperature increases when the sensed temperature is between a first predetermined temperature threshold and a second predetermined temperature threshold, and the heating resistor is configured to generate heat when current flows therethrough; The second predetermined temperature threshold is higher than the first predetermined temperature threshold, and the resistance value of the thermistor at the first predetermined temperature threshold is 1*10^3 times to 1*10^6 times the resistance value at the second predetermined temperature threshold.

2. The battery cell according to claim 1, characterized in that: The battery cell further comprises an end cover, the housing has an opening, and the end cover is used to close the opening; The heating resistor includes a resistance wire, and the resistance wire is connected to a side of the end cover close to the electrode assembly along the thickness direction.

3. The battery cell according to claim 1, characterized in that: The electrode assembly has a first surface, which is a plane with the largest area of ​​the electrode assembly, and the thermistor is arranged on the first surface.

4. The battery cell according to claim 3, characterized in that: The thermistor is disposed at the center of the first surface.

5. The battery cell according to claim 3, characterized in that: The two first surfaces are located on both sides of the electrode assembly along the first direction. The heating circuit includes a plurality of thermistors connected in series. The thermistor is disposed on at least one of the first surfaces.

6. The battery cell according to claim 1, characterized in that: The battery cell is a cylindrical battery, and the thermistor is arranged on the cylindrical surface of the electrode assembly.

7. The battery cell according to claim 1, characterized in that: The thermistor is a negative temperature coefficient thermistor.

8. The battery cell according to claim 7, characterized in that: The thermistor is configured such that its resistance value can drop below 0.01 ohm when the sensed temperature is not lower than the second predetermined temperature threshold.

9. The battery cell according to any one of claims 1 to 8, characterized in that: When the sensed temperature is not lower than the second predetermined temperature threshold, the resistance R2 of the heating resistor is 2 to 10 times the total resistance R3 of the thermistor, and the resistance R2 of the heating resistor is not lower than 0.02 ohms and not higher than 0.1 ohms.

10. The battery cell according to claim 9, characterized in that: The resistance value R2 of the heating resistor is 3 to 5 times the total resistance value R3 of the thermistor.

11. The battery cell according to any one of claims 1 to 8, characterized in that: The first predetermined temperature threshold is not higher than 25°C, and the second predetermined temperature threshold is not lower than 60°C and not higher than 150°C.

12. The battery cell according to any one of claims 1 to 8, characterized in that: The nominal voltage of the battery cell is in the range of 2.5V to 5V.

13. The battery cell according to any one of claims 1 to 8, characterized in that: When the sensed temperature is lower than the first predetermined temperature threshold, the current flowing through the heating circuit does not exceed 10% of the self-discharge current of the battery cell.

14. A battery device, characterized in that: The invention comprises a plurality of battery cells according to any one of claims 1 to 13.

15. The battery device according to claim 14, characterized in that: The plurality of battery cells are arranged with their large surfaces facing each other.

16. An electrical device, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 13, the battery device according to claim 14 or claim 15, wherein the battery cell or the battery device is used for storing or providing electric energy.

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