Battery cell, battery device, and electric device

Abstract

This application provides a battery cell, a battery device, and an electrical device, belonging to the technical field of new energy batteries. The battery cell includes a casing, electrode assembly, a thermistor, and an insulating component. The thermistor is a positive temperature coefficient thermistor, comprising a first connecting portion, a fusible portion, and a second connecting portion connected in sequence. The fusible portion includes multiple fusible links spaced apart from each other. Within a preset temperature range, the resistance value of the fusible portion is greater than the resistance values ​​of the first connecting portion and the second connecting portion. The first connecting portion is electrically connected to the electrode assembly, and the second connecting portion is electrically connected to the electrode terminals. The insulating component is disposed between the first and second connecting portions, and at least two fusible links are separated by the insulating component. When the battery cell is subjected to a large current, the fusible portion melts first, cutting off the internal circuit of the battery cell, providing overcurrent protection, improving the battery cell's resistance to thermal runaway, and enhancing the safety and reliability of the battery cell.

Description

Technical Field

[0001] This application belongs to the technical field of new energy batteries, and more specifically, relates to a battery cell, a battery device, and an electrical device. Background Technology

[0002] With the increasing popularity of new energy batteries, battery safety has become a growing concern. One of the common safety issues encountered during battery use is thermal runaway.

[0003] A battery cell is the basic unit of a battery device. Thermal runaway of a battery device usually starts from the thermal runaway of a single battery cell. Therefore, it is necessary to improve the structure of the battery cell to reduce the probability of thermal runaway, thereby preventing thermal runaway and improving the safety of battery use. At the same time, it is not necessary to excessively affect the normal use of the battery cell. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell, a battery device, and an electrical device to alleviate the thermal runaway problem of a battery cell under instantaneous high current impact, reduce the impact on the normal overcurrent of the battery cell, and improve the safety of battery use.

[0005] In a first aspect, this application provides a battery cell, which includes a casing, an electrode assembly, a thermistor, and an insulating member. The casing has a receiving cavity and electrode terminals are provided on the casing. The electrode assembly is disposed within the receiving cavity. The thermistor is a positive temperature coefficient thermistor, which includes a first connecting portion, a fusible portion, and a second connecting portion connected in sequence. The fusible portion includes a plurality of fusible links spaced apart from each other, with one end of each fusible link connected to the first connecting portion and the other end connected to the second connecting portion. Within a preset temperature range, the resistance value of the fusible link is greater than the resistance values ​​of the first connecting portion and the second connecting portion. The thermistor is disposed within the receiving cavity, and the first connecting portion is electrically connected to the electrode assembly, and the second connecting portion is electrically connected to the electrode terminals. The insulating member is located between the first connecting portion and the second connecting portion, and at least two fusible links are separated by the insulating member.

[0006] By adopting the above scheme, the resistance values ​​of the first and second connecting parts are smaller than those of the fuse section. This results in a lower overall resistance value of the thermistor, which helps reduce the internal resistance of the battery cell during normal overcurrent, lowers the energy consumption of the battery cell, and reduces the heat generation of the battery cell. The resistance value of the thermistor is primarily generated by the fuse section. Since the resistance change trend of the thermistor is directly proportional to the temperature change trend, when a large current passes through the battery cell, the thermistor heats up, causing its temperature to rise. This increases the thermistor's resistance value. Because the resistance value of the fuse section is greater than that of the first and second connecting parts, under the same current, the fuse section generates more heat and its resistance value increases faster. Temperature and resistance mutually promote each other during the passage of large current, causing the fuse section to melt first, cutting off the internal circuit of the battery cell, providing overcurrent protection, improving the battery cell's resistance to thermal runaway, and enhancing the safety and reliability of the battery cell. Therefore, the above-mentioned solution of this application enables the battery cell to have a large overcurrent flow during normal use and the battery cell to melt quickly under high current impact, thus taking into account both the normal use performance of the battery cell and the safety performance under high current impact, thereby improving the safety of the battery cell.

[0007] Furthermore, to achieve a certain current-carrying capacity, the current-carrying area of ​​the fuse needs to reach a certain value. If the fuse is set as a single piece, compared to multiple fuse links, the fuse will be thicker. Under current conditions, the temperature difference between the inside and the surface of the fuse is larger, making it less likely to melt compared to multiple thinner fuse links. Therefore, setting it as multiple fuse links is beneficial to improving the thermistor's response capability to large currents, that is, improving the thermistor's sensitivity and reliability.

[0008] By placing an insulating element between at least two fuse posts, arcing between the two separated fuse posts can be prevented, further improving the safety of the battery cell.

[0009] In some embodiments, the flow area of ​​the fuse portion is smaller than the flow area of ​​the first connection portion and smaller than the flow area of ​​the second connection portion.

[0010] The smaller the current-carrying area, the greater the resistance, and the faster the heating rate under high current, the faster the resistance increases. Therefore, by adopting the above scheme, the resistance of the fuse part can be made greater than the resistance of the first connection part and the resistance of the second connection part, so that the fuse part can melt and break in time under high current.

[0011] In some embodiments, the flow area of ​​the fuse portion is greater than or equal to 10% of the flow area of ​​the first connection portion, and less than or equal to 30% of the flow area of ​​the first connection portion;

[0012] And / or, the flow area of ​​the fuse portion is greater than or equal to 10% of the flow area of ​​the second connection portion, and less than or equal to 30% of the flow area of ​​the second connection portion.

[0013] By adopting the above scheme, the resistance value of the fuse part is greater than that of the first connection part and the second connection part, so that the fuse part can respond to the large current impact and melt first. At the same time, it can reduce the impact of the overcurrent caused by the small overcurrent area of ​​the fuse part on the overcurrent of the battery cell under normal use. Thus, the fuse part can take into account both the normal overcurrent under normal use of the battery cell and the timely melting under the large current impact.

[0014] In some embodiments, the dimension of the fuse rod perpendicular to the flow direction is greater than or equal to 1 mm and less than or equal to 5 mm.

[0015] By adopting the above scheme, the smaller the diameter of the fuse column, the smaller the internal and external temperature difference, the larger the resistance value, and the faster the fuse fuse to blow under high current, resulting in more timely fuse blowing. However, when the diameter of the fuse column is too small, there will be problems such as high manufacturing difficulty and difficulty in guaranteeing the overcurrent effect under normal use. Therefore, controlling the diameter of the fuse column within the above range not only improves the fuse column's response capability to high current, but also reduces the processing and manufacturing difficulty, and reduces the impact on the overcurrent effect of the fuse column when the battery cell is in normal use.

[0016] In some embodiments, the dimension of the fuse rod in the flow direction is greater than or equal to 2 mm and less than or equal to 10 mm.

[0017] By adopting the above scheme, the larger the size of the fuse post in the current-passing direction, the longer the circuit at the fuse post, the higher the resistance value of the fuse post, the faster the heating and melting speed under high current, and the better the melting effect. However, when the size of the fuse post in the current-passing direction is too large, the fuse post will occupy too much space inside the casing, reducing the energy density of the battery cell. Therefore, setting the height of the fuse post within the above range improves the timely melting effect of the fuse post while reducing the impact on the energy density of the battery cell.

[0018] In some embodiments, the housing includes a housing and an end cap, with electrode terminals disposed on the end cap; a thermistor is disposed between the electrode assembly and the end cap.

[0019] The battery cell also includes a sealing ring, which is located between the thermistor and the housing to seal the thermistor and the housing.

[0020] By adopting the above solution, the electrolyte in the space where the electrode assembly is located can be prevented from flowing from the edge of the thermistor to the side where the end cap is located, thereby improving the stability of the internal structure of the battery cell.

[0021] In some embodiments, the insulating element and the sealing ring are integrally formed.

[0022] By adopting the above solution, the number of parts is reduced, the insulation components and sealing rings can be manufactured simultaneously, and the assembly steps of the insulation components, sealing rings and thermistors are reduced, thereby improving the manufacturing efficiency of battery cells and reducing costs.

[0023] In some embodiments, the first connecting portion includes a first material, the second connecting portion includes a second material, and the fusible portion includes a third material. Within a preset temperature range, and when the first material, the second material, and the third material are under the same temperature conditions, the resistance value of the third material is greater than the resistance value of the first material and greater than the resistance value of the second material.

[0024] By utilizing the different resistance values ​​of the materials of the fuse section, the first connection section, and the second connection section, the resistance value of the fuse section can be greater than that of the first connection section and the second connection section, enabling the thermistor to handle both normal overcurrent during normal use of the battery cell and timely fuse-off during high current surges.

[0025] In some embodiments, the first connection portion is adapted to the structure of the electrode assembly near the thermistor side; and / or, the second connection portion is adapted to the structure of the electrode terminal near the thermistor side.

[0026] By adopting the above scheme, the setting of the fuse only needs to consider the temperature coefficient of resistance, without having to take into account the connection with the electrode assembly and electrode terminals. The thermistor is more feasible and the design is simpler.

[0027] In some embodiments, the thermistor is made of a polymer-based material or a ceramic-based material.

[0028] By adopting the above scheme, the polymer-based material is a composite material in which conductive fillers are dispersed in a polymer matrix. The melting principle of the polymer-based material is as follows: at room temperature, the conductive fillers form a conductive path with very low resistance; when the temperature rises to the polymer melting point (i.e., the switching temperature), the polymer expands in volume, destroying the conductive path and causing the resistance to rise sharply.

[0029] Ceramic matrix materials are composite materials formed by doping rare earth elements into electronic ceramic materials. The melting principle of ceramic matrix materials is as follows: at room temperature, the material has very low resistance and can pass current normally; when the temperature rises and reaches the Curie point of the material, the internal crystal structure undergoes a phase transition, changing from a ferroelectric phase to a paraelectric phase. The spontaneous polarization of the material disappears, a grain boundary barrier appears, destroying the conductive path and causing the resistance to rise sharply.

[0030] Both of the above types of materials can achieve a positive correlation between the resistance of the thermistor and temperature, enabling the effective fusing of the fuse under high current impact, thus providing more options for realizing the solution of this application.

[0031] In some embodiments, when the material of the thermistor includes a polymer-based material, the polymer-based material includes at least one of polyethylene / carbon black composite material, polyethylene / carbon nanotube composite material, polyethylene / graphene composite material, polyvinylidene fluoride composite material, and epoxy resin-based composite material; and / or, when the material of the thermistor includes a ceramic-based material, the ceramic-based material includes at least one of barium titanate-based ceramic and bismuth vanadate-based ceramic.

[0032] The polymer-based and ceramic-based materials provided above can both achieve a positive correlation between the resistance of the thermistor and temperature, providing more and more specific options for realizing the solution of this application.

[0033] In some embodiments, the housing is configured as an annular columnar structure that is closed relative to the external environment, with a first hole formed in the middle of the annular columnar structure, and the electrode assembly disposed around the hole wall of the first hole.

[0034] By adopting the above scheme, the electrode assembly is arranged around the hole wall of the first hole, so that when the battery cell is in use, the heat in the middle of the electrode assembly can be dissipated through the first hole, thus slowing down the heating rate in the middle of the electrode assembly.

[0035] In some embodiments, the thermistor is provided with a through hole, the wall of the first hole passes through the through hole, and the thermistor and the wall of the first hole are insulated and sealed together.

[0036] By adopting the above scheme, the position of the thermistor relative to the first hole is the same as the position of the electrode assembly relative to the first hole, facilitating the connection between the thermistor and the electrode assembly. During normal operation of the battery cell, the heat from the thermistor can also be dissipated through the first hole, slowing down the temperature rise rate of the battery cell at the thermistor and resulting in a slower resistance increase during normal operation. The insulated and sealed design between the thermistor and the wall of the first hole prevents electrolyte leakage from the space containing the electrode assembly through the space between the thermistor and the wall of the first hole, ensuring the normal operation of the battery cell.

[0037] In some embodiments, the battery cell further includes an adapter electrically connecting the thermistor and the electrode assembly; and / or, the adapter electrically connecting the electrode terminals and the thermistor.

[0038] Compared to direct connection between the thermistor and electrode assembly, or direct connection between the electrode terminals and the thermistor, this setup eliminates the need for the thermistor's material and structure to accommodate both the electrode assembly and electrode terminals. Instead, it uses an adapter as an intermediary to adapt to the structures of both the electrode assembly and electrode terminals, thus reducing the difficulty of processing, manufacturing, and material selection for the thermistor.

[0039] In some embodiments, an adapter that electrically connects the thermistor and the electrode assembly is disposed between the thermistor and the electrode assembly, and the electrode assembly is provided with an electrode tab on the side near the adapter; the adapter is provided with a slot, the slot opening facing the electrode assembly; the electrode tab is inserted into the slot and connected to the adapter within the slot.

[0040] By adopting the above solution, the slot opening faces the electrode assembly. After the tab extends from the electrode assembly, it can be directly inserted into the slot without bending or with only a slight bending, and connected to the adapter in the slot. Compared with the connection method of the tab and adapter in the prior art, the above solution of this application can reduce the bending damage and defects that occur during the connection of the tab and adapter, and improve the yield of the connection link between the tab and adapter.

[0041] In some embodiments, the adapter is integrated with the thermistor.

[0042] By adopting the above solution, the number of components in a single battery cell is reduced, thereby lowering the assembly cost of the battery cell.

[0043] In some embodiments, the adapter is made of aluminum or copper.

[0044] Typically, the positive electrode material of an electrode assembly is aluminum, and the negative electrode material is copper. Correspondingly, the positive electrode tab is made of aluminum, and the negative electrode tab is made of copper. Setting the material of the adapter to be the same as that of the positive or negative electrode tab can reduce the resistance between the adapter and the positive or negative electrode tab, thereby reducing the internal resistance of the battery cell during normal use.

[0045] Secondly, this application provides a battery device including a plurality of battery cells as described in any of the embodiments of the first aspect above.

[0046] Thirdly, this application provides an electrical device that includes a battery cell as described in any of the embodiments of the first aspect above, or a battery device as described in any of the embodiments of the second aspect, wherein the battery cell or the battery device provides power to the electrical device. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of an electrical device provided in an embodiment of this application.

[0049] Figure 2This is an exploded view of a battery device provided in an embodiment of this application.

[0050] Figure 3 This is an exploded structural diagram of the first type of battery cell provided in the embodiments of this application.

[0051] Figure 4 This is a schematic diagram of the structure of a thermistor provided in an embodiment of this application.

[0052] Figure 5 for Figure 4 The image shows a cross-sectional view of the thermistor taken from the fused section.

[0053] Figure 6 A cross-sectional view of the second type of thermistor provided in this application embodiment, taken from the fused portion.

[0054] Figure 7 A cross-sectional view of the third type of thermistor provided in the embodiments of this application, cut from the fused portion.

[0055] Figure 8 A cross-sectional view of the fourth type of thermistor provided in the embodiments of this application, cut from the fused portion.

[0056] Figure 9 This is a side view of an assembly structure of a thermistor and an insulating component provided in an embodiment of this application.

[0057] Figure 10 for Figure 9 A cross-sectional view at section AA in the middle.

[0058] Figure 11 for Figure 9 The sectional view is obtained by cutting the assembled structure along a section parallel to the first direction.

[0059] Figure 12 This is a schematic diagram of the assembly of a thermistor and a sealing ring provided in an embodiment of this application.

[0060] Figure 13 for Figure 12 A sectional view at section BB in the middle.

[0061] Figure 14 This is a structural diagram of an insulating component and a sealing ring integrally formed according to an embodiment of this application.

[0062] Figure 15 This is an exploded structural diagram of the second type of battery cell provided in the embodiments of this application.

[0063] Figure 16 This is an exploded structural diagram of the third type of battery cell provided in the embodiments of this application.

[0064] Figure 17 This is a schematic diagram of the structure of an adapter provided in an embodiment of this application.

[0065] Figure 18 This is an exploded structural diagram of the fourth type of battery cell provided in the embodiments of this application.

[0066] The following are the labeling elements in the figure:

[0067] 01. Vehicle; 1000. Battery unit; 2000. Controller; 3000. Motor;

[0068] 1100, Box body; 1110, Structural panel;

[0069] 1200, Battery cell; 1210, Casing; 1211, Housing; 1212, End cap; 1213, First hole; 1220, Electrode assembly; 1221, Tab; 1230, Electrode terminal; 1240, Thermistor; 1241, First connection part; 1242, Fuse part; 1243, Second connection part; 1244, Fuse post; 1245, Through hole; 1250, Insulator; 1251, Through hole sealing ring; 1260, Sealing ring; 1280, Adapter; 1281, Slot; 1300, Explosion-proof valve; X, First direction. Detailed Implementation

[0070] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0071] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0072] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", 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 this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0073] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

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

[0075] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0076] With the increasing popularity of new energy batteries, battery safety has become a growing concern. One of the common safety issues during battery use is thermal runaway, which is typically caused by high-current surges.

[0077] There are many reasons why a battery device may experience a large current surge. For example, connecting the battery device to a circuit with a voltage much higher than its rated voltage can cause a momentary large current to the battery device; using a charging device with a charging rate that is not compatible with the original charging rate to charge the battery device at a high rate can cause the battery to be subjected to a large current; if the battery device is damaged or aged, continuing to use the battery device under such circumstances may result in high-rate overcharging or over-discharging, causing the battery device to be subjected to a large current, and so on.

[0078] When a battery device is subjected to a high current surge, the temperature and pressure inside the battery cell rise rapidly. If this continues for a long time, it may damage the internal structure of the battery cell, affect its electrical performance, or even cause thermal runaway, seriously affecting the service life and safety of the battery device.

[0079] In related technologies, batteries are equipped with a Battery Management System (BMS). The BMS can intelligently manage and maintain the battery, monitor its status, and mitigate the aforementioned problems, reducing the probability of overcharging and over-discharging, thereby extending the battery's lifespan. However, when individual battery cells experience high current surges, the BMS struggles to adjust them in a timely manner.

[0080] Based on this, this application proposes a scheme to use a thermistor with a positive temperature coefficient (PTC) in a battery cell. This scheme involves placing the thermistor in the casing of the battery cell and connecting the thermistor to the internal circuit of the battery cell. For example, the thermistor can be connected between the electrode terminals and the electrode assembly, so that the current must pass through the thermistor when the battery cell is in use. In this case, once the battery cell is subjected to a large current surge, the heat generated causes the resistance value of the thermistor to rise rapidly, thereby cutting off the circuit of the battery cell, providing overcurrent protection for the battery cell, improving the battery's resistance to thermal runaway, and enhancing the battery's safety and reliability.

[0081] The battery disclosed in this application can be used in electrical devices that use batteries as a power source or in various energy storage systems that use batteries as energy storage elements. Electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0082] For ease of explanation, the following embodiments will be described using vehicle 01 as an example of an electrical device.

[0083] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 01 provided in some embodiments of this application. The vehicle 01 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery device 1000 is installed inside the vehicle 01. The battery device 1000 can be located at the bottom, front, or rear of the vehicle 01. The battery device 1000 can be used to power the vehicle 01; for example, the battery device 1000 can serve as the operating power source for the vehicle 01. The vehicle 01 may also include a controller 2000 and a motor 3000. The controller 2000 is used to control the battery device 1000 to supply power to the motor 3000, for example, to meet the power needs of the vehicle 01 during starting, navigation, and driving.

[0084] In some embodiments of this application, the battery device 1000 can not only serve as the operating power source for the vehicle 01, but also as the driving power source for the vehicle 01, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 01.

[0085] Please refer to Figure 2 , Figure 2This is an exploded structural diagram of a battery device 1000 provided in some embodiments of this application. The battery device 1000 includes a housing 1100 and battery cells 1200, with the battery cells 1200 housed within the housing 1100. The housing 1100 provides space for the battery cells 1200, and the housing 1100 can adopt various structures.

[0086] like Figure 2 As shown, in some embodiments, the housing 1100 is a hollow structure defined by multiple structural plates 1110. The structural plates 1110 are plate-like structures and can be made of steel plates, iron plates, rigid plastic plates, etc. The multiple structural plates 1110 can be fixed using methods such as cable ties, bolts, or snap-fits to define the space for accommodating the battery cells 1200. Depending on the number and structural requirements of the battery cells 1200, the space accommodating the battery cells 1200 can be a cuboid space, a cylindrical space, a prism space, etc.

[0087] In the battery device 1000, there can be multiple battery cells 1200. These multiple battery cells 1200 can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that the multiple battery cells 1200 are connected in both series and parallel. The multiple battery cells 1200 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 1200 is housed within the housing 1100. Alternatively, the battery device 1000 can also consist of multiple battery cells 1200 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is also housed within the housing 1100. The battery device 1000 may also include other structures; for example, the battery device 1000 may also include a busbar component for realizing the electrical connection between the multiple battery cells 1200.

[0088] Each battery cell 1200 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 1200 can be cylindrical, flat, cuboid, or other shapes.

[0089] Please refer to Figure 3 , Figure 3 This is an exploded structural diagram of a battery cell 1200 provided in some embodiments of this application. The battery cell 1200 refers to the smallest unit constituting the battery device 1000. As shown, the battery cell 1200 includes a housing 1210, an electrode assembly 1220, and other functional components.

[0090] Typically, the outer casing 1210 consists of a housing 1211 and an end cap 1212. The end cap 1212 is a component that covers the opening of the housing 1211 to isolate the internal environment of the battery cell 1200 from the external environment. The shape of the end cap 1212 can be adapted to the shape of the housing 1211 to fit it. Optionally, the end cap 1212 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 1212 is less prone to deformation under pressure and impact, allowing the battery cell 1200 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 1230 can be provided on the end cap 1212. The electrode terminals 1230 can be used for electrical connection with the electrode assembly 1220 for outputting or inputting electrical energy into the battery cell 1200. In some embodiments, the end cap 1212 may also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 1200 reaches a threshold. The end cap 1212 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating structure may also be provided on the inner side of the end cap 1212. The insulating structure can be used to isolate the electrical connection components in the housing 1211 from the end cap 1212 to reduce the risk of short circuit. For example, the insulating structure can be plastic, rubber, etc.

[0091] The housing 1211 is a component used to cooperate with the end cap 1212 to form the internal environment of the battery cell 1200, wherein the formed internal environment can accommodate the electrode assembly 1220, electrolyte, and other components. The housing 1211 and the end cap 1212 can be independent components. An opening can be provided on the housing 1211, and the end cap 1212 closes the opening to form the internal environment of the battery cell 1200. Alternatively, the end cap 1212 and the housing 1211 can be integrated. Specifically, the end cap 1212 and the housing 1211 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 1211, the end cap 1212 closes the housing 1211. The housing 1211 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 1211 can be determined according to the specific shape and size of the electrode assembly 1220. The shell 1211 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special restrictions on this.

[0092] Electrode assembly 1220 is a component in battery cell 1200 where electrochemical reactions occur. The housing 1211 may contain one or more electrode assemblies 1220. Electrode assembly 1220 may be formed by stacking and winding positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of electrode assembly 1220, while the portions of the positive and negative electrode sheets without active material each constitute tabs 1221. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of battery device 1000, active ions, such as lithium ions, reversibly insert and extract between the positive and negative electrode sheets to achieve charging and discharging. The tabs 1221 connect to electrode terminals 1230 to form a current loop.

[0093] Please refer to Figure 3 and Figure 4 , Figure 3 This is an exploded structural diagram of the first type of battery cell provided in the embodiments of this application. Figure 4 This application provides a schematic diagram of the structure of a thermistor. For example... Figure 3 and Figure 4 As shown, this application embodiment provides a battery cell 1200, which includes a housing 1210, an electrode assembly 1220, and a thermistor 1240. The housing 1210 has a receiving cavity and electrode terminals 1230 are provided on the housing 1210. The electrode assembly 1220 is disposed in the receiving cavity. The thermistor 1240 is a positive temperature coefficient thermistor, which includes a first connecting portion 1241, a fuse portion 1242, and a second connecting portion 1243 connected in sequence. Within a preset temperature range, the resistance value of the fuse portion 1242 is greater than the resistance values ​​of the first connecting portion 1241 and the second connecting portion 1243. The thermistor 1240 is disposed in the receiving cavity, and the first connecting portion 1241 is electrically connected to the electrode assembly 1220, and the second connecting portion 1243 is electrically connected to the electrode terminal 1230.

[0094] The housing 1210 includes a housing 1211 and an end cap 1212. The electrode terminal 1230 can be located on the housing 1211 or on the end cap 1212. The housing 1211 can also serve as the electrode terminal 1230 through electrical connection with the electrode assembly 1220. Figure 3 The illustration is based on the example of electrode terminal 1230 being located on end cap 1212.

[0095] The thermistor 1240 is a type of thermistor whose resistance is positively correlated with temperature. That is, the resistance of the thermistor 1240 increases with increasing temperature; the higher the temperature, the greater the resistance. When the resistance increases to a certain level, current can no longer pass through the thermistor 1240, or only a very small current in the microampere range can pass through it. This phenomenon is referred to as thermistor 1240 melting. After the thermistor 1240 melts, the circuit of the battery cell 1200 is broken, the rate of temperature and voltage rise within the battery cell 1200 slows down, and the temperature and pressure within the battery cell 1200 gradually return to normal, thus providing timely protection for the battery cell 1200.

[0096] The first connecting part 1241 is electrically connected to the electrode assembly 1220, and the second connecting part 1243 is electrically connected to the electrode terminal 1230. Therefore, the structure and material selection of the fuse part 1242 only need to consider whether it can be melted at a preset temperature or current, without having to consider whether it can be reasonably connected to the electrode assembly 1220 and the electrode terminal 1230. This greatly reduces the design difficulty of the fuse part 1242.

[0097] The first connecting part 1241 can be electrically connected to the electrode assembly 1220 through direct connection or indirect connection.

[0098] Similarly, the second connecting part 1243 is electrically connected to the electrode terminal 1230. This can be achieved by directly connecting the second connecting part 1243 to the electrode terminal 1230, or by indirectly connecting the second connecting part 1243 to the electrode terminal 1230.

[0099] Taking the direct connection between the first connecting part 1241 and the electrode assembly 1220 as an example, in order to better connect with the electrode assembly 1220 and reduce the resistance at the connection point, the first connecting part 1241 can be adapted to the structure of the electrode assembly 1220 near the thermistor 1240. For example, if the electrode assembly 1220 is cylindrical and the tab 1221 is located at one end of the cylinder, then the structure of the first connecting part 1241 can be disc-shaped, and the end face of the first connecting part 1241 near the tab 1221 at least covers the area where the tab 1221 is located. This allows the tabs 1221 in different areas to be connected to the first connecting part 1241 at close range, resulting in lower resistance at the connection point between the first connecting part 1241 and the electrode assembly 1220 and easier connection.

[0100] Similarly, the second connection portion 1243 can be adapted to the structure of the electrode terminal 1230 near the thermistor 1240 to reduce the connection resistance between the second connection portion 1243 and the electrode terminal 1230. This will not be elaborated further in the embodiments of this application.

[0101] Furthermore, the materials of the first connecting part 1241 and the second connecting part 1243 can be the same as or different from the fusible part 1242, as long as the resistance value of the fusible part 1242 is greater than the resistance value of the first connecting part 1241 and the resistance value of the second connecting part 1243 within the preset temperature range.

[0102] The preset temperature range includes the temperature range of the thermistor 1240 under normal overcurrent conditions, and the temperature range of the thermistor 1240 when a large current flows through it until it melts. For example, when the battery cell 1200 is in normal use, the current flows normally through the thermistor 1240, and the thermistor 1240 heats up normally. Under this temperature condition, the resistance value of the fuse part 1242 is greater than the resistance values ​​of the first connection part 1241 and the second connection part 1243. When a large current flows through the thermistor 1240, the temperature of the thermistor 1240 rises sharply. When the temperature of the thermistor 1240 rises to any value, the resistance value of the fuse part 1242 is greater than the resistance values ​​of the first connection part 1241 and the second connection part 1243.

[0103] For example, the preset temperature range can be -40°C to 150°C.

[0104] Furthermore, the preset temperature range refers to the overall temperature conditions of the thermistor 1240, not the individual temperature conditions of the fuse 1242, the first connection 1241, and the second connection 1243. Under any temperature conditions, there may be slight differences between the temperature of the fuse 1242 and the temperatures of the first connection 1241 and the second connection 1243, but these differences do not affect the overall temperature conditions of the thermistor 1240.

[0105] By adopting the above solution, compared with the fuse part 1242, the resistance values ​​of the first connecting part 1241 and the second connecting part 1243 are smaller. This results in a smaller overall resistance value of the thermistor 1240, which helps to reduce the internal resistance value of the battery cell 1200 during normal overcurrent, reduce the energy consumption of the battery cell 1200, and reduce the heat generation of the battery cell 1200. The resistance value of the thermistor 1240 is mainly generated by the fuse part 1242. When a large current passes through the battery cell 1200, the thermistor 1240 heats up, and with the temperature of the thermistor 1240 rising, its resistance value also increases accordingly. During this process, since the resistance of the fuse 1242 is greater than that of the first connection 1241 and the second connection 1243, the temperature of the fuse 1242 increases the fastest. Correspondingly, the rate of increase in the resistance of the fuse 1242 is also faster than that of the first connection 1241 and the second connection 1243. This causes the fuse 1242 to melt first, cutting off the internal circuit of the battery cell 1200, providing overcurrent protection for the battery cell 1200, improving the battery cell 1200's resistance to thermal runaway, and enhancing the safety and reliability of the battery cell 1200.

[0106] Therefore, the above-mentioned solution of this application enables the battery cell 1200 to have a large overcurrent flow during normal use, and the battery cell 1200 can quickly melt and break under high current impact, thus taking into account both the normal use performance of the battery cell 1200 and the safety performance under high current impact, thereby improving the safety of the battery cell 1200.

[0107] In the above scheme, there are several ways to make the resistance value of the fuse 1242 greater than the resistance value of the first connecting part 1241 and greater than the resistance value of the second connecting part 1243. For example, it can be achieved by making the material of the fuse 1242 different from the materials of the first connecting part 1241 and the second connecting part 1243; it can also be achieved by making the structure of the fuse 1242 different from the structures of the first connecting part 1241 and the second connecting part 1243; or it can be achieved by making both the material and structure of the fuse 1242 different from the materials and structures of the first connecting part 1241 and the second connecting part 1243. The following embodiments illustrate several specific implementation schemes.

[0108] In some embodiments, the first connecting portion 1241 includes a first material, the second connecting portion 1243 includes a second material, and the fusible portion 1242 includes a third material. Within a preset temperature range, and when the first material, the second material, and the third material are under the same temperature conditions, the resistance value of the third material is greater than the resistance value of the first material and greater than the resistance value of the second material.

[0109] The first material and the second material can be the same or different.

[0110] By utilizing the different resistance values ​​of the materials of the fuse part 1242, the first connecting part 1241, and the second connecting part 1243, the resistance value of the fuse part 1242 can be made greater than the resistance values ​​of the first connecting part 1241 and the second connecting part 1243, so that the thermistor 1240 can both withstand normal overcurrent during normal use of the battery cell 1200 and timely fuse during high current surges.

[0111] In some embodiments, the flow area of ​​the fuse portion 1242 is smaller than the flow area of ​​the first connecting portion 1241 and smaller than the flow area of ​​the second connecting portion 1243.

[0112] The current-carrying area of ​​any part of the thermistor 1240 refers to the cross-sectional area of ​​that part perpendicular to the current-carrying direction, where the current-carrying direction is the direction in which the current flows. For example, as... Figure 3 and Figure 4 As shown, in the battery cell 1200, the current flows through the thermistor 1240 along the first direction X. The current-carrying area of ​​the thermistor 1240 is the cross-sectional area of ​​the thermistor perpendicular to the first direction X.

[0113] The size of the current-carrying area in different parts of the 1240 thermistor affects the resistance value of that part. Generally, the smaller the current-carrying area, the larger the resistance value of the corresponding part, the faster the heating rate under high current, and the faster the resistance value increases.

[0114] Therefore, by adopting the above scheme, the resistance value of the fuse part 1242 can be made greater than the resistance value of the first connection part 1241 and the resistance value of the second connection part 1243, so that the fuse part 1242 can be melted in time under high current.

[0115] In some embodiments, the flow area of ​​the fuse portion 1242 is greater than or equal to 10% of the flow area of ​​the first connecting portion 1241 and less than or equal to 30% of the flow area of ​​the first connecting portion 1241; and / or, the flow area of ​​the fuse portion 1242 is greater than or equal to 10% of the flow area of ​​the second connecting portion 1243 and less than or equal to 30% of the flow area of ​​the second connecting portion 1243.

[0116] The fusible link 1242 may satisfy only that its flow area is greater than or equal to 10% of the flow area of ​​the first connecting part 1241 and less than or equal to 30% of the flow area of ​​the first connecting part 1241, or it may satisfy only that its flow area is greater than or equal to 10% of the flow area of ​​the second connecting part 1243 and less than or equal to 30% of the flow area of ​​the second connecting part 1243, or it may simultaneously satisfy that the flow area of ​​the fusible link 1242 is greater than or equal to 10% of the flow area of ​​the first connecting part 1241 and less than or equal to 30% of the flow area of ​​the first connecting part 1241, and that the flow area of ​​the fusible link 1242 is greater than or equal to 10% of the flow area of ​​the second connecting part 1243 and less than or equal to 30% of the flow area of ​​the second connecting part 1243.

[0117] Although a smaller current-passing area of ​​the fuse 1242 is more conducive to timely fuse-breaking under high current, when the current-passing area of ​​the fuse 1242 is too small, the resistance of the fuse 1242 during normal overcurrent of the battery cell 1200 will be too large, resulting in increased internal resistance of the battery cell 1200, decreased output current, increased heat generation of the battery cell 1200 during normal use, and affecting the electrochemical performance and lifespan of the battery cell 1200.

[0118] The above-mentioned solution of this application limits the overcurrent area of ​​the fuse part 1242 by the overcurrent area of ​​the first connecting part 1241 and the second connecting part 1243, so that the overcurrent area of ​​the fuse part 1242 is within a suitable range. This ensures that the resistance value of the fuse part 1242 is greater than the resistance values ​​of the first connecting part 1241 and the second connecting part 1243, thereby enabling the fuse part 1242 to preferentially melt in response to large current surges. At the same time, it reduces the impact of an excessively small overcurrent area of ​​the fuse part 1242 on the overcurrent of the battery cell 1200 under normal use. Thus, the fuse part 1242 can take into account both the normal overcurrent under normal use of the battery cell 1200 and timely melting under large current surges.

[0119] When the overall flow area of ​​the fuse section 1242 is fixed, the flow area of ​​the fuse section 1242 may include only one region or multiple independent regions. Correspondingly, the fuse section 1242 may include one fuse structure or multiple independent fuse structures. The multiple independent fuse structures are respectively connected to the first connecting part 1241 and the second connecting part 1243, and each has its own flow.

[0120] Specifically, such as Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, Figure 5 for Figure 4 The image shows a cross-sectional view of the thermistor taken from the fused section. Figure 6 , Figure 7 and Figure 8 Cross-sectional views of three other different thermistors taken from their fuse sections are shown. Please refer to... Figures 4 to 8 In some embodiments, the fuse portion 1242 includes a plurality of fuse posts 1244 spaced apart from each other, with one end of each fuse post 1244 connected to a first connecting portion 1241 and the other end connected to a second connecting portion 1243.

[0121] Each fuse pin 1244 can be cylindrical, prismatic, or tubular, etc. There are gaps between different fuse pins 1244 so that they are not connected to each other. For example, in... Figure 5 In the illustrated embodiment, the multiple fuse holders are cylindrical with equal dimensions; Figure 6 In the illustrated embodiment, the multiple fuse bars are strip-shaped columns of varying sizes; in Figure 7 In the illustrated embodiment, the multiple fuse bars are strip-shaped columns of equal size, although the shape of the fuse bars in this embodiment is similar to... Figure 6 They are roughly the same, but their arrangement is different. Figure 6 The embodiments shown are different; in Figure 8 In the illustrated embodiment, the multiple fuse pillars are prism-shaped with rounded corners at the edges to reduce tip discharge.

[0122] In all the above situations, each fuse post 1244 constitutes an independent fuse structure. To achieve a certain current-carrying capacity, the current-carrying area of ​​the fuse portion 1242 needs to reach a certain value. If the fuse portion 1242 is set as a single piece, compared to setting multiple fuse posts 1244, the fuse portion 1242 will be thicker. Under current conditions, the temperature difference between the inside and the surface of the fuse portion 1242 is larger, making it less likely to melt compared to multiple thinner fuse posts 1244. Therefore, setting multiple fuse posts 1244 is beneficial to improving the response capability of the thermistor 1240 to large currents, that is, improving the sensitivity and reliability of the thermistor 1240.

[0123] In some embodiments, the dimension of the fuse rod 1244 perpendicular to the flow direction is greater than or equal to 1 mm and less than or equal to 5 mm.

[0124] Fuse column 1244 can be Figure 5 , Figure 6 , Figure 7 and Figure 8 The structure shown in any of the accompanying drawings may also be other structures not listed in this application, such as the fuse column 1244 being a quadrangular prism or other irregular structure.

[0125] In the above case, the fuse column 1244 has multiple directions perpendicular to the flow direction. The dimensions in the multiple directions can be the same or different, as long as the dimensions in the multiple directions are greater than or equal to 1 mm and less than or equal to 5 mm.

[0126] For example, the fuse rod 1244 is cylindrical, and the diameter of the fuse rod 1244 can be 1 mm, 3.2 mm, 4 mm, 5 mm, etc.

[0127] Understandably, the smaller the dimension of a single fuse element 1244 perpendicular to the current flow direction, the smaller the temperature difference between the inside and outside of the fuse element 1244, the higher the resistance of the fuse element 1244, the faster it heats up and melts under high current, and the better the fusing effect. However, when the dimension of the fuse element 1244 perpendicular to the current flow direction is too small, there will be problems with manufacturing difficulty and difficulty in guaranteeing the current flow performance under normal use.

[0128] Therefore, in this embodiment of the application, the dimensions of the fuse post 1244 perpendicular to the current direction are controlled within the above-mentioned range, which not only improves the fusing effect of the fuse post 1244 under high current, but also reduces the processing and manufacturing difficulty of the fuse post 1244, and to a certain extent ensures good current flow of the fuse post 1244 when the battery cell 1200 is in normal use.

[0129] In some embodiments, the dimension of the fuse rod 1244 in the flow direction is greater than or equal to 2 mm and less than or equal to 10 mm.

[0130] The dimension of the fuse column 1244 in the current-passing direction refers to the actual length of the current passing through the fuse column 1244. For example, if the fuse column 1244 is bent, the current path on the fuse column 1244 is also bent. In this case, the dimension of the fuse column 1244 in the current-passing direction is the actual total length of the fuse column 1244 after bending.

[0131] In another specific example, such as Figure 3 and Figure 4 As shown, when the thermistor 1240 is subjected to current along the first direction X, and the first connecting part 1241, the fuse post 1244, and the second connecting part 1243 are arranged sequentially along the first direction X, since the two ends of the fuse post 1244 are respectively connected to the first connecting part 1241 and the second connecting part 1243, the dimension of the fuse post 1244 in the current-passing direction is the distance between the first connecting part 1241 and the second connecting part 1243.

[0132] The dimensions of the fuse rod 1244 in the flow direction can be 2 mm, 4 mm, 5 mm, 8 mm, 8.5 mm, 10 mm, etc.

[0133] The larger the dimension of the fuse post 1244 in the current-passing direction, the longer the circuit at the fuse post 1244, the higher the resistance value of the fuse post 1244, the faster the heating and melting speed under high current, and the better the melting effect. However, when the dimension of the fuse post 1244 in the current-passing direction is too large, the fuse post 1244 will occupy too much space inside the casing 1210, reducing the energy density of the battery cell 1200. In this embodiment of the application, the dimension of the fuse post 1244 in the current-passing direction is set within the above-mentioned range, which improves the melting effect of the fuse post 1244 and reduces the impact on the energy density of the battery cell 1200.

[0134] When a battery cell 1200 includes multiple fuse posts 1244, if the distance between any two fuse posts 1244 is too close, the air between the fuse posts 1244 may be broken down, and an electric arc may be generated between the fuse posts 1244. That is, adjacent fuse posts 1244 may be electrically connected, which will affect the current flow inside the battery cell 1200 and is not allowed.

[0135] Figure 9 This is a side view of an assembly structure of a thermistor and an insulating component provided in an embodiment of this application. Figure 10 for Figure 9 A cross-sectional view at section AA in the middle. Figure 11 for Figure 9 The assembly structure shown is a cross-sectional view obtained by cutting along a section parallel to the first direction X. To prevent arcing between adjacent fuse posts 1244, as... Figure 9 , Figure 10 and Figure 11 As shown, in some embodiments, the battery cell 1200 further includes an insulating member 1250, which is located between the first connecting portion 1241 and the second connecting portion 1243, and at least two fuse posts 1244 are separated by the insulating member 1250.

[0136] The material of the insulating component 1250 can be any insulating material such as plastic, ceramic, or mica.

[0137] The dimension of the insulating member 1250 in the first direction X is equal to the distance between the first connecting portion 1241 and the second connecting portion 1243, so that adjacent fuse posts 1244 can be insulated and isolated by the insulating member throughout the entire range along the first direction X.

[0138] The number of insulating elements 1250 can be multiple, and multiple insulating elements 1250 are respectively disposed between two adjacent fuse posts 1244. The number of insulating elements 1250 can also be one, with different parts of the single insulating element 1250 located between adjacent fuse posts 1244 to achieve insulation isolation of the fuse posts 1244.

[0139] For example, in some embodiments, the insulating member 1250 is plate-shaped and has multiple through holes, with each fusible link 1244 located within one of the through holes. In this embodiment, the area outside the through holes of the insulating member 1250 serves as an insulating barrier between adjacent fusible links 1244.

[0140] As can be seen, by setting up the insulating component 1250, even if the two fuse posts 1244 are close together, the probability of arcing between the two fuse posts 1244 can be reduced, which greatly improves the safety and current stability of the battery cell 1200.

[0141] Figure 12 This is a schematic diagram illustrating the assembly of a thermistor and a sealing ring, as provided in an embodiment of this application. Figure 3 and Figure 12 In some embodiments, the housing 1210 includes a housing 1211 and an end cap 1212, with electrode terminals 1230 disposed on the end cap 1212; a thermistor 1240 is disposed between the electrode assembly 1220 and the end cap 1212. The battery cell 1200 also includes a sealing ring 1260, which is disposed between the thermistor 1240 and the housing 1211 to seal the thermistor 1240 and the housing 1211.

[0142] Compared to the housing 1211, the end cap 1212 is generally simple in shape and easy to process. The electrode terminal 1230 is set on the end cap 1212. The electrode terminal 1230 can be set on the end cap 1212 before the end cap 1212 is assembled with the housing 1211, making the connection between the electrode terminal 1230 and the end cap 1212 more convenient.

[0143] Since the electrode terminal 1230 is located on the end cover 1212, the thermistor 1240 is located between the electrode assembly 1220 and the end cover 1212. This means that the thermistor 1240 is located between the electrode assembly 1220 and the electrode terminal 1230, which facilitates the electrical connection of the thermistor 1240 to the electrode terminal 1230 and the electrode assembly 1220 respectively.

[0144] In the battery cell 1200, the electrolyte serves to facilitate ion conduction between the positive and negative electrodes. Therefore, only the electrode assembly 1220 requires electrolyte wetting, while other components do not. In fact, electrolyte wetting may affect the performance and circuit structure of other components. For example, if electrolyte fills the spaces between the fusible links 1244, current cannot flow between the first connection 1241 and the second connection 1243 through multiple links alone. This will affect the fusing of the fusible links 1244, thus hindering the thermistor 1240 from performing optimally.

[0145] In this embodiment, by setting a sealing ring 1260 between the thermistor 1240 and the housing 1211, a seal can be achieved between the thermistor 1240 and the housing 1211. This prevents the electrolyte in the space where the electrode assembly 1220 is located from flowing from the gap between the thermistor 1240 and the housing 1211 to the side of the thermistor 1240 away from the electrode assembly 1220, thereby improving the stability of the internal structure of the battery cell 1200.

[0146] The sealing ring 1260 can be an elastic sealing ring, such as rubber. During the assembly of the thermistor 1240 and the housing 1211, the sealing ring 1260 is compressed and deformed, filling the space between the thermistor 1240 and the housing 1211, thereby achieving a seal between the thermistor 1240 and the housing 1211.

[0147] Therefore, by adopting the above solution, it is possible to prevent the electrolyte in the space where the electrode assembly 1220 is located from flowing from the edge of the thermistor 1240 to the side where the end cover 1212 is located, thus affecting the circuit structure of the battery cell 1200 and improving the stability of the internal structure of the battery cell 1200.

[0148] Figure 13 for Figure 12 A sectional view at section BB in the middle. Figure 14 This is a structural diagram illustrating an embodiment of the present application where an insulating element and a sealing ring are integrally formed. Figure 13 and Figure 14 As shown, in some embodiments, the insulating element 1250 and the sealing ring 1260 are integrally formed.

[0149] In other words, the insulating element 1250 and the sealing ring 1260 are made of the same material and are naturally connected together without the aid of other connecting structures.

[0150] For example, both the insulating component 1250 and the sealing ring 1260 are made of rubber and are integrally molded using thermoplastic molding.

[0151] By adopting the above solution, the insulating component 1250 and the sealing ring 1260 are combined into one part, reducing the number of components. In this case, the insulating component 1250 and the sealing ring 1260 can be manufactured simultaneously and assembled with the thermistor 1240 in one step, reducing the assembly steps of the insulating component 1250, the sealing ring 1260 and the thermistor 1240, improving the manufacturing efficiency of the battery cell 1200 and reducing costs.

[0152] Please combine Figure 3 , Figure 13 and Figure 14In one specific embodiment, the battery cell 1200 is a cylindrical battery, the casing 1211 is cylindrical with openings at both ends, the end cap 1212 is a circular plate and is disposed at the opening at the end of the casing 1211, and the electrode assembly 1220 is installed inside the casing 1211. The first connecting portion 1241 and the second connecting portion 1243 are both circular plates, and the fuse portion 1242 includes a plurality of cylindrical fuse rods 1244, which are evenly distributed between the first connecting portion 1241 and the second connecting portion 1243. The insulating component 1250 is disc-shaped and has a through hole 1245 for the fusible link 1244 to pass through. The edge of the insulating component 1250 is provided with a flange that is thicker than the insulating component 1250. The flange is configured as a sealing ring 1260. The sealing ring 1260 extends to the outer periphery of the first connecting portion 1241 on the side near the first connecting portion 1241 and insulates and seals the first connecting portion 1241 with the housing 1211. The sealing ring 1260 extends to the outer periphery of the second connecting portion 1243 on the side near the second connecting portion 1243 and insulates and seals the second connecting portion 1243 with the housing 1211.

[0153] The above-described embodiment is a specific structural scheme when the battery cell 1200 of this application is configured as a cylindrical battery. It can be seen that in the above scheme, the insulating component 1250, the thermistor 1240 and the sealing ring 1260 achieve good cooperation through reasonable structural design, forming an integral structure. During assembly, the integral structure consisting of the thermistor 1240, the insulating component 1250 and the sealing ring 1260 can be assembled into the housing 1211 in one go. The number of parts is small, and the assembly is simple and quick.

[0154] In some embodiments, the thermistor 1240 is made of a polymer-based material or a ceramic-based material.

[0155] By adopting the above scheme, the polymer-based material is a composite material in which conductive fillers are dispersed in a polymer matrix. The melting principle of the polymer-based material is as follows: at room temperature, the conductive fillers form a conductive path with very low resistance, which can be used for normal overcurrent under normal use of the battery cell 1200; when the temperature rises to the polymer melting point (i.e., the switching temperature), the polymer volume expands, destroying the conductive path, causing the resistance to rise sharply, and the internal circuit of the battery cell 1200 is disconnected from the thermistor 1240.

[0156] Ceramic matrix materials are composite materials formed by doping rare earth elements into electronic ceramic materials. The melting principle of ceramic matrix materials is as follows: at room temperature, the material has very low resistance and can pass current normally; when the temperature rises and reaches the Curie point of the material, the internal crystal structure undergoes a phase transition, changing from a ferroelectric phase to a paraelectric phase. The spontaneous polarization of the material disappears, a grain boundary barrier appears, destroying the conductive path and causing the resistance to rise sharply.

[0157] Both of the above types of materials can achieve a positive correlation between the resistance of the thermistor 1240 and temperature, providing an alternative solution for realizing the embodiments of this application.

[0158] Furthermore, the state change that the above two types of materials undergo during the melting process is a solid-to-solid change. Compared with materials that need to undergo a solid-to-liquid state change during melting, when the above two types of materials are used as thermistors 1240, there is no need to consider the flow problem after the melting part 1242 melts into a liquid state. In the absence of a large current, there is no risk that the internal circuit of the battery cell 1200 will be reconnected due to the flow of liquid.

[0159] After the high current disappears, as the temperature of the thermistor 1240 decreases, its crystal structure gradually recovers, and its resistance value also decreases. The thermistor 1240 then conducts again, allowing the battery cell 1200 to continue operating. Therefore, the melting of the thermistor 1240, formed from the two types of materials mentioned above, is reversible and will not cause permanent damage to the battery cell 1200.

[0160] The following examples further illustrate polymer-based materials and ceramic-based materials.

[0161] In some embodiments, when the material of the thermistor 1240 includes a polymer-based material, the polymer-based material includes at least one of polyethylene / carbon black composite material, polyethylene / carbon nanotube composite material, polyethylene / graphene composite material, polyvinylidene fluoride composite material, and epoxy resin-based composite material.

[0162] Polyethylene / carbon black composite material refers to a composite material with polyethylene as the matrix and carbon black as the conductive filler.

[0163] Polyethylene / carbon nanotube composite material refers to a composite material with polyethylene as the matrix and carbon nanotubes as the conductive filler.

[0164] Polyethylene / graphene composite material refers to a composite material with polyethylene as the matrix and graphene or its derivatives as conductive fillers.

[0165] Polyvinylidene fluoride composite material refers to a composite material that uses polyvinylidene fluoride or its copolymers as the polymer matrix and does not contain other conductive fillers.

[0166] Epoxy resin-based composite materials refer to composite materials that use thermosetting epoxy resin as the matrix and dopants in other conductive fillers.

[0167] All the polymer-based materials provided in the above embodiments can be used as materials for the thermistor 1240, providing optional solutions for realizing the function of the thermistor 1240 in the embodiments of this application.

[0168] In some embodiments, when the thermistor 1240 is made of a ceramic-based material, the ceramic-based material includes at least one of barium titanate-based ceramic and bismuth vanadate-based ceramic.

[0169] Ceramic-based materials refer to doped ceramic-based semiconductor ceramic composite materials. Their effect originates from the change of grain boundary potential barrier, and the switching temperature is usually determined by the Curie point of the material.

[0170] Barium titanate-based ceramics are composite materials formed by doping barium titanate (BaTiO3) with rare earth elements (such as Y, Nb, Sb, etc.) to make it semiconductor.

[0171] Bismuth vanadate-based ceramics are composite materials formed by doping bismuth vanadate with rare earth elements (such as yttrium, niobium, antimony, etc.) to make it semiconductor.

[0172] The ceramic-based materials provided in the above embodiments can all be used as materials for the thermistor 1240, providing optional solutions for realizing the function of the thermistor 1240 in the embodiments of this application.

[0173] The polymer-based and ceramic-based materials provided above can both achieve a positive correlation between the resistance of the thermistor 1240 and temperature, providing more and more specific options for implementing the solutions of the embodiments of this application. In actual selection, the various parts of the thermistor 1240 can use the same material or different materials, as long as the resistance requirements of the embodiments of this application are met.

[0174] The following provides several more specific structures of the battery cell 1200, and explains the possible placement of the thermistor 1240 in the battery cell 1200 in conjunction with the specific structure of the battery cell 1200.

[0175] Figure 15 This is an exploded structural diagram of the second type of battery cell provided in an embodiment of this application. Figure 15 As shown, in some embodiments, the housing 1210 is configured as an annular columnar structure that is closed relative to the external environment, a first hole 1213 is formed in the middle of the annular columnar structure, and the electrode assembly 1220 is disposed around the hole wall of the first hole 1213.

[0176] The electrode assembly 1220 can be wrapped around the hole wall of the first hole 1213 and the outer peripheral wall of the housing 1210 to form a ring structure.

[0177] The structure of the battery cell 1200 allows heat in the middle of the electrode assembly 1220 to dissipate through the first hole 1213, slowing down the heating rate in the middle of the electrode assembly 1220 and extending the service life of the battery cell 1200.

[0178] Please continue to refer to Figure 15 In some embodiments, the thermistor 1240 is provided with a through hole 1245, the wall of the first hole 1213 passes through the through hole 1245, and the thermistor 1240 and the wall of the first hole 1213 are insulated and sealed together.

[0179] The insulation seal between the thermistor 1240 and the wall of the first hole 1213 can be achieved by setting an insulation seal structure between the side wall of the through hole 1245 and the wall of the first hole 1213. For example, a rubber ring is composited on the side wall of the through hole 1245. When the thermistor 1240 is installed in the housing 1210, the rubber ring is compressed and tightly abuts against the wall of the first hole 1213, thereby achieving an insulation seal between the thermistor 1240 and the wall of the first hole 1213.

[0180] Please combine Figure 12 , Figure 13 and Figure 14 In some embodiments, when the battery cell 1200 includes an insulating member 1250, the insulating member 1250 extends into the through hole 1245 to form a through hole sealing ring 1251, so as to achieve an insulating seal between the thermistor 1240 and the hole wall of the first hole 1213.

[0181] Since the wall of the first hole 1213 passes through the through hole 1245 on the thermistor 1240, when the battery cell 1200 is in normal use, the heat of the thermistor 1240 can also be dissipated through the wall of the first hole 1213, which slows down the heating rate of the battery cell 1200 at the thermistor 1240 and reduces the probability that the resistance of the thermistor 1240 will rise too quickly or even melt when the battery cell 1200 is in normal use.

[0182] An insulating seal is provided between the thermistor 1240 and the wall of the first hole 1213 to prevent electrolyte in the space where the electrode assembly 1220 is located from leaking through the space between the thermistor 1240 and the wall of the first hole 1213.

[0183] Figure 16 This is an exploded structural diagram of the third type of battery cell provided in an embodiment of this application. Figure 16 As shown, in some embodiments, the battery cell 1200 further includes an adapter 1280 electrically connected to the thermistor 1240 and the electrode assembly 1220; and / or, the adapter 1280 electrically connected to the electrode terminal 1230 and the thermistor 1240.

[0184] One or more adapters 1280 can be provided. When one adapter is provided, the adapter 1280 can electrically connect the thermistor 1240 and the electrode assembly 1220, or it can electrically connect the electrode terminal 1230 and the adapter 1280. When multiple adapters 1280 are provided, at least one adapter 1280 is electrically connected to the thermistor 1240 and the electrode assembly 1220, and another adapter 1280 is electrically connected to the electrode terminal 1230 and the thermistor 1240. The electrical connection can be a direct connection or an indirect connection.

[0185] Figure 16 The illustration only shows an adapter positioned between the thermistor 1240 and the electrode assembly 1220. The adapter 1280 can be made of copper, aluminum, or other metals. For example, when the adapter 1280 is connected to the positive electrode tab of the electrode assembly 1220, since the positive electrode tab is typically made of aluminum, the adapter 1280 can also be made of aluminum to reduce the contact resistance between the adapter 1280 and the positive electrode tab. When the adapter 1280 is connected to the negative electrode tab of the electrode assembly 1220, since the negative electrode tab is typically made of copper, the adapter 1280 can also be made of copper. Of course, the material of the adapter 1280 can also be different from the material of the connected tab 1221; neither will affect the circuit continuity between the electrode assembly 1220 and the thermistor 1240.

[0186] In the above embodiments of this application, the thermistor 1240 is electrically connected to the electrode assembly 1220 via an adapter 1280, and / or the electrode terminal 1230 and the thermistor 1240 are electrically connected via an adapter 1280. Compared with the direct connection between the thermistor 1240 and the electrode assembly 1220, and the direct connection between the electrode terminal 1230 and the thermistor 1240, the material and structure of the thermistor 1240 do not need to take into account the structures of the electrode assembly 1220 and the electrode terminal 1230. Instead, the adapter 1280 is used as an intermediate medium to adapt to the structures of the electrode assembly 1220 and the electrode terminal 1230 respectively, which reduces the processing and manufacturing difficulty and material selection difficulty of the thermistor 1240.

[0187] The following provides examples of possible structures for adapter 1280.

[0188] Figure 17 This is a schematic diagram of an adapter provided in an embodiment of this application. Please refer to... Figure 16 and Figure 17In some embodiments, an adapter 1280 that electrically connects the thermistor 1240 and the electrode assembly 1220 is disposed between the thermistor 1240 and the electrode assembly 1220. An electrode tab 1221 is provided on the side of the electrode assembly 1220 near the adapter 1280. A slot 1281 is provided on the adapter 1280, with the slot opening of the slot 1281 facing the electrode assembly 1220. The electrode tab 1221 is inserted into the slot 1281 and connected to the adapter 1280 within the slot 1281.

[0189] The electrode 1221 can be either a positive electrode or a negative electrode.

[0190] The slot 1281 may or may not pass through the adapter 1280. When the slot 1281 passes through the adapter 1280, the slot 1281 has two slots, one of which faces the electrode assembly 1220. When the slot 1281 does not pass through the adapter 1280, the slot 1281 has one slot, which faces the electrode assembly 1220.

[0191] Since the slot of the slot 1281 faces the electrode assembly 1220, the tab 1221, after extending from the electrode assembly 1220, can be directly inserted into the slot 1281 without bending or with only a slight bending, and connected to the adapter 1280 within the slot 1281. Compared with the connection method between the tab 1221 and the adapter 1280 in the prior art, the above solution of this application can reduce bending damage and the generation of poor solder joints and bad spots during the connection process between the tab 1221 and the adapter 1280, and improve the yield rate of the connection link between the tab 1221 and the adapter 1280.

[0192] The tabs 1221 and slots 1281 can be inserted in a one-to-one correspondence, or multiple tabs 1221 can be stacked and inserted into one slot 1281. After the tabs 1221 are inserted into the slots 1281, their connection with the adapter 1280 can be by welding, bonding, etc. Among them, welding can be laser welding, ultrasonic welding, etc., and bonding can be by conductive adhesive.

[0193] In some other embodiments, the adapter 1280 can also be configured as a sheet-like conductive sheet without a slot structure. One side of the conductive sheet is connected to the tab 1221, and the other side is connected to the thermistor 1240. This structure is relatively simple, and will not be described in detail in this embodiment of the application.

[0194] In some embodiments, the adapter 1280 is integrated with the thermistor 1240.

[0195] In this context, "integrated setup" refers to a single unit. Specifically, this integration can be achieved through integral manufacturing or by using other processes or structures to connect the adapter 1280 and the thermistor 1240 together, making them a single unit. When the adapter 1280 and the thermistor 1240 are connected using other processes or structures to form an integrated structure, the materials of the adapter 1280 and the thermistor 1240 can be the same or different. For example, the thermistor 1240 can be made of barium titanate-based ceramic material, while the adapter 1280 can be made of metal. The adapter 1280 and the thermistor 1240 can be bonded together using conductive adhesive to achieve the integrated setup.

[0196] In the scheme where the adapter 1280 and the thermistor 1240 are integrated, the adapter 1280 may not have a slot structure and may be connected to the tab 1221 using any connection scheme in related technologies, or a wider slot structure may be provided so that the tab 1221 can be inserted.

[0197] By adopting the above solution, the adapter 1280 and the thermistor 1240 can be integrated and used as a whole, which reduces the number of parts in the battery cell 1200 and lowers the assembly cost of the battery cell 1200.

[0198] In some embodiments, the adapter 1280 is made of aluminum or copper.

[0199] Copper and aluminum are two materials with good electrical conductivity and low cost. Using them as materials for adapter 1280 can improve the conductivity of adapter 1280 and reduce the cost of adapter 1280.

[0200] Furthermore, in the electrode assembly 1220, the positive electrode tab is usually made of aluminum and the negative electrode tab is made of copper. In actual manufacturing, the material of the adapter 1280 can be set to be the same as the material of the connected tab 1221, thereby reducing the contact resistance between the adapter 1280 and the tab 1221, thereby reducing the internal resistance of the battery cell 1200 and improving the electrical performance of the battery cell 1200.

[0201] Figure 18 This is an exploded structural diagram of the fourth type of battery cell provided in an embodiment of this application. Figure 18As shown, in some embodiments, the battery cell includes a housing 1210, an electrode assembly 1220, a thermistor 1240, an insulator 1250, a sealing ring 1260, and an adapter 1280. The housing 1210 includes a shell 1211 and two oppositely arranged end caps 1212, which together form a receiving cavity. The electrode assembly 1220, the thermistor 1240, the insulator 1250, the sealing ring 1260, and the adapter 1280 are all located within the receiving cavity. The end caps 1212 are provided with electrode terminals 1230. The electrode assembly 1220 is provided with a tab 1221 on the side near the end cap 1212. From the tab 1221 to the electrode terminal 1230, the adapter 1280 and the thermistor 1240 are arranged sequentially. The insulator 1250 and the sealing ring 1260 are integrally formed and cooperate with the thermistor 1240 to form a whole according to the scheme described in the aforementioned embodiments.

[0202] In this embodiment, the specific structure, materials, and connection relationships between each component and other components can be referred to the description of the foregoing related embodiments, and will not be repeated in this embodiment of the application.

[0203] The solution of this embodiment combines the advantages of the battery cells in the aforementioned embodiments, and the resulting battery cell has a compact and reasonable structure. It can take into account both good overcurrent under normal use and timely melting under high current impact, and has good heat dissipation and is easy to assemble.

[0204] Please refer to Figure 2 This application also provides a battery device 1000, which includes a plurality of battery cells 1200 as described in any of the above embodiments.

[0205] Optionally, the multiple battery cells 1200 can be prismatic, cylindrical, or pouch cells. Figure 2 Take a cylindrical battery as an example.

[0206] Taking a cylindrical battery cell 1200 as an example, multiple battery cells 1200 can be arranged longitudinally along the axial direction to form a battery device 1000. Multiple battery cells 1200 can also be arranged laterally along the direction perpendicular to the axial direction to form a battery device 1000. Multiple battery cells 1200 can also be arranged longitudinally along the axial direction to form a module, and multiple modules can be arranged laterally to form a battery device 1000.

[0207] Multiple battery cells 1200 can be electrically connected through direct contact of electrode terminals 1230, or the electrode terminals 1230 of different battery cells 1200 can be connected by using a pad as a conductive medium to achieve electrical connection between battery cells 1200. Those skilled in the art can make the settings as needed.

[0208] Because the battery cell 1200 in any of the above embodiments is used, each battery cell 1200 constituting the battery device 1000 can have low internal resistance and high-efficiency current output during normal use, and can independently fuse when encountering large current, more accurately cutting off the electrical connection between the problematic battery cell and other battery cells, protecting the battery device 1000 and improving the safety of the battery device 1000.

[0209] This application provides an electrical device, including the battery device 1000 in any of the above embodiments, which provides power to the electrical device.

[0210] For details regarding the specific types of electrical devices and the power supply principle of the battery device 1000, please refer to the description in the aforementioned scheme; further details will not be repeated here.

[0211] Because of the increased safety of the battery device 1000, electrical devices using the aforementioned battery device 1000 are safer.

[0212] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A single battery cell, characterized in that: include: The housing has a receiving cavity, and the housing is provided with electrode terminals; The electrode assembly is disposed within the receiving cavity; A thermistor, specifically a positive temperature coefficient thermistor, comprises a first connecting portion, a fusible portion, and a second connecting portion that are sequentially electrically connected. The fusible portion includes a plurality of fusible links spaced apart from each other, with one end of each fusible link connected to the first connecting portion and the other end connected to the second connecting portion. Within a preset temperature range, the resistance value of the fusible portion is greater than the resistance values ​​of both the first and second connecting portions. The thermistor is disposed within the receiving cavity, and the first connecting portion is electrically connected to the electrode assembly, while the second connecting portion is electrically connected to the electrode terminals. An insulating element is disposed between the first connecting portion and the second connecting portion, and at least two of the fusible links are separated by the insulating element.

2. The battery cell as described in claim 1, characterized in that: The flow area of ​​the fuse is smaller than the flow area of ​​the first connection and smaller than the flow area of ​​the second connection.

3. The battery cell as described in claim 2, characterized in that: The current-passing area of ​​the fuse is greater than or equal to 10% of the current-passing area of ​​the first connection part, and less than or equal to 30% of the current-passing area of ​​the first connection part; And / or, the flow area of ​​the fuse portion is greater than or equal to 10% of the flow area of ​​the second connection portion, and less than or equal to 30% of the flow area of ​​the second connection portion.

4. The battery cell as described in claim 1, characterized in that: The dimension of the fuse rod perpendicular to the flow direction is greater than or equal to 1 mm and less than or equal to 5 mm.

5. The battery cell as described in claim 1, characterized in that: The dimension of the fuse rod in the flow direction is greater than or equal to 2 mm and less than or equal to 10 mm.

6. The battery cell as described in claim 1, characterized in that: The housing includes a shell and an end cap, with the electrode terminals disposed on the end cap; the thermistor is disposed between the electrode assembly and the end cap; The battery cell also includes a sealing ring, which is disposed between the thermistor and the housing to seal the thermistor and the housing.

7. The battery cell as described in claim 6, characterized in that: The insulating component is integrally formed with the sealing ring.

8. The battery cell as described in claim 1, characterized in that: The first connecting part includes a first material, the second connecting part includes a second material, and the fusible part includes a third material. Within the preset temperature range, and when the first material, the second material, and the third material are under the same temperature conditions, the resistance value of the third material is greater than the resistance value of the first material and greater than the resistance value of the second material.

9. The battery cell as described in claim 1, characterized in that: The first connection portion is adapted to the structure of the electrode assembly near the thermistor; And / or, the second connection portion is adapted to the structure of the electrode terminal on the side near the thermistor.

10. The battery cell as described in claim 1, characterized in that: The thermistor is made of polymer-based materials or ceramic-based materials.

11. The battery cell as described in claim 10, characterized in that: When the material of the thermistor includes a polymer-based material, the polymer-based material includes at least one of polyethylene / carbon black composite material, polyethylene / carbon nanotube composite material, polyethylene / graphene composite material, polyvinylidene fluoride composite material, and epoxy resin-based composite material. And / or, when the material of the thermistor includes a ceramic-based material, the ceramic-based material includes at least one of barium titanate-based ceramic and bismuth vanadate-based ceramic.

12. The battery cell as described in claim 1, characterized in that: The housing is configured as an annular columnar structure that is closed relative to the external environment, and a first hole is formed in the middle of the annular columnar structure, with the electrode assembly arranged around the hole wall of the first hole.

13. The battery cell as described in claim 12, characterized in that: The thermistor has a through hole, the wall of the first hole passes through the through hole, and the thermistor and the wall of the first hole are insulated and sealed together.

14. The battery cell as described in claim 1, characterized in that: The battery cell also includes an adapter, which electrically connects the thermistor to the electrode assembly; And / or, the adapter electrically connects the electrode terminals and the thermistor.

15. The battery cell as described in claim 14, characterized in that: The adapter that electrically connects the thermistor and the electrode assembly is disposed between the thermistor and the electrode assembly, and the electrode assembly has a tab on the side near the adapter; The adapter is provided with a slot, and the slot opening faces the electrode assembly; The electrode tab is inserted into the slot and connected to the adapter within the slot.

16. The battery cell as described in claim 14, characterized in that: The adapter is integrated with the thermistor.

17. The battery cell as described in claim 14, characterized in that: The adapter is made of aluminum or copper.

18. A battery device, characterized in that: It includes the battery cells described in any one of claims 1-17.

19. An electrical appliance, characterized in that, The device includes a battery cell as described in any one of claims 1-17, or a battery device as described in claim 18, wherein the battery cell or the battery device provides power to the electrical device.

Images