Battery cell and battery pack

Abstract

This application discloses a battery cell and a battery pack, relating to the field of power battery technology. In the battery cell, an electrode assembly is disposed within a housing; a top cover is connected to the housing along a first direction; an insulating member is disposed within the housing, located on the side of the top cover near the electrode assembly; a connecting piece is disposed within the housing and electrically connected to the electrode assembly; a first end of a resistor is connected to the top cover, and a second end of the resistor passes through the insulating member along the first direction and is connected to the connecting piece; the top cover and the resistor have mutually cooperating mating parts. The resistor can conduct electricity to form a short circuit between the top cover and the connecting piece when the temperature of the battery cell continuously rises, causing the battery to discharge rapidly to a low charge level, thereby reducing the battery's charge level. Even if thermal runaway of the battery cell is triggered, the risk of the discharged battery catching fire or exploding is reduced. This improves battery safety and reduces the risk of thermal runaway propagation.

Description

Technical Field

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

[0002] With environmental issues becoming increasingly prominent, a low-carbon economy has become the mainstream of future economic development. The increasingly severe air pollution situation has further promoted the rise of new energy vehicles. Hybrid vehicles and pure electric vehicles, as representatives of new energy vehicles, have gradually gained recognition from manufacturers and consumers. Power batteries, as the main power source for new energy vehicles, have become one of the key components of electric vehicles.

[0003] During the use of lithium-ion batteries, individual battery cells may experience thermal runaway. Excessively high thermal runaway temperatures can cause deformation of the battery cell's top cover, leading to a short circuit between the negative electrode connector and the top cover. Utility Model Content

[0004] The purpose of this application is to provide a battery cell to solve the technical problem of short circuit between the negative electrode connector and the top cover caused by excessively high thermal runaway temperature of the battery cell, and to provide a battery pack including the battery cell.

[0005] To achieve the above objectives, a first aspect of this application provides a battery cell having a first orientation. The battery cell includes: a housing; an electrode assembly disposed within the housing; a top cover connected to the housing along the first orientation; an insulating member disposed within the housing, the insulating member being located on the side of the top cover near the electrode assembly; a connecting piece disposed within the housing, the connecting piece being electrically connected to the electrode assembly; and a resistor, a first end of which is connected to the top cover, and a second end of which passes through the insulating member along the first orientation and is connected to the connecting piece; one of the top cover and the resistor has a first mating portion, and the other has a second mating portion for engaging with the first mating portion.

[0006] In some embodiments, the first mating part is a protrusion and the second mating part is a groove; the first mating part protrudes in the direction close to the electrode assembly, and the second mating part is recessed in the direction close to the electrode assembly along the first direction, with the first mating part located inside the second mating part.

[0007] In some embodiments, the first mating part is a groove and the second mating part is a protrusion; the first mating part is recessed in the direction of approaching the electrode assembly, and the second mating part protrudes in the direction of approaching the electrode assembly along the first direction, and the second mating part is located inside the first mating part.

[0008] In some embodiments, one of the connecting piece and the resistor is provided with a third mating portion, which is disposed opposite to the first mating portion along a first direction, and the other is provided with a fourth mating portion for the third mating portion to engage.

[0009] In some embodiments, the third mating part is configured as a protrusion and the fourth mating part is configured as a groove. The third mating part protrudes in the direction away from the electrode assembly, and the fourth mating part is recessed in the direction away from the electrode assembly. The third mating part is located inside the fourth mating part.

[0010] In some embodiments, the resistor includes at least two first main body portions and a connecting portion. The two ends of the first main body portions pass through an insulating member along a first direction. The connecting portion is connected to two adjacent first main body portions to form a second mating portion and a fourth mating portion. The second mating portion and the fourth mating portion are spaced apart along the first direction.

[0011] In some embodiments, the third mating part is a groove, the fourth mating part is a protrusion, the third mating part is recessed in the direction away from the electrode assembly, the fourth mating part is protruded in the direction away from the electrode assembly, and the fourth mating part is located inside the third mating part.

[0012] In some embodiments, the resistor includes a second mating portion, a second main body portion, and a fourth mating portion connected sequentially along a first direction. The two ends of the second main body portion are disposed in an insulating member along the first direction. The second mating portion is connected to one end of the second main body portion away from the electrode assembly, and the fourth mating portion is connected to one end of the second main body portion near the electrode assembly.

[0013] In some embodiments, the battery cell further has a second direction perpendicular to the first direction, and the electrode assembly has a tab that is connected to the electrode body in the first direction; the battery cell also includes a terminal post that passes through the top cover, and a connecting piece that connects the terminal post and the tab in the first direction, wherein the terminal post and resistors are arranged at intervals along the second direction, and there are multiple resistors, which are disposed at both ends of the top cover along the second direction, and the terminal post is located between two adjacent resistors.

[0014] A second aspect of this application provides a battery pack including the battery cells described above.

[0015] The technical advantage of this application lies in the fact that a resistor is connected between the top cover and the connecting piece. Under normal circumstances, the resistor is in an insulating state, meaning the top cover and the connecting piece are insulated from each other and cannot form a conductive path, thus not affecting the normal operation of the battery. When the temperature of the battery cell continues to rise, the heat transfer will first cause the resistor to reach its conduction temperature, thus forming a short circuit between the top cover and the connecting piece, prompting the battery to discharge rapidly to a low charge, thereby reducing the battery's charge level. When the temperature of the battery cell further rises to the thermal runaway temperature, even if thermal runaway of the battery cell is triggered, the low charge level at this time significantly reduces the risk of fire and explosion. At the same time, it also avoids the phenomenon that excessively high thermal runaway temperatures can cause the top cover to deform, resulting in a short circuit between the top cover and the positive / negative electrode connecting piece, generating sparks. This improves the safety of battery use and reduces the risk of the spread of thermal runaway from the battery cell. Attached Figure Description

[0016] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the structure of a battery cell provided in Embodiment 1 of this application.

[0018] Figure 2 This is a cross-sectional view of a battery cell provided in Embodiment 1 of this application.

[0019] Figure 3 for Figure 2 Enlarged view of part A in the middle.

[0020] Figure 4 This is a cross-sectional view of the resistor provided in Embodiment 1 of this application.

[0021] Figure 5 This is a cross-sectional view of a battery cell provided in Embodiment 2 of this application.

[0022] Figure 6 for Figure 5 Enlarged view of part A' in the middle.

[0023] Figure 7 This is a partial cross-sectional view of a battery cell provided in Embodiment 3 of this application.

[0024] Figure 8 This is a partial cross-sectional view of a battery cell provided in Embodiment 4 of this application.

[0025] Figure 9 This is a cross-sectional view of a battery cell provided in Embodiment 5 of this application.

[0026] Figure 10 This is a schematic diagram of the battery pack provided in an embodiment of this application.

[0027] The components in the attached diagram are labeled as follows:

[0028] 1-Shell; 10-Cavity; 11-Opening; 2-Electrode assembly; 21-Electrode body; 22-Electrode tab; 3-Top cover; 31-First mating part; 4-Insulator; 5-Connecting piece; 51-Third mating part; 6-Resistor; 61-Second mating part; 62-Fourth mating part; 601-First main body; 602-Connecting part; 603-Second main body; 7-Terminal post; 100-Battery cell; 200-Box; 300-Box cover. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0030] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used 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, and therefore should not be construed as a limitation of this application. 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 indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0032] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0033] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0034] Thermal runaway refers to an abnormal reaction occurring inside a battery, causing a rapid rise in battery temperature and triggering a chain reaction that generates a large amount of heat and gas. When a single battery cell experiences thermal runaway, the increased temperature leads to accelerated decomposition and reaction of internal battery materials, producing even more heat and gas. During thermal runaway, the top cover deforms due to excessive temperature. At this point, the insulation protection of the positive / negative electrode connection of the battery cell fails, easily causing a short circuit with the top cover and generating sparks. Ultimately, this can lead to the battery cell igniting and causing uncontrollable heat spread within electrical equipment, severely impacting safety performance.

[0035] To address the aforementioned issues, the battery cell provided in this application includes a resistor connected between the top cover and the connecting piece. Under normal circumstances, the resistor is in an insulating state, meaning the top cover and connecting piece are insulated from each other, preventing the formation of a conductive path and thus not affecting the normal operation of the battery. When the temperature of the battery cell rises continuously, heat transfer first causes the resistor to reach its conduction temperature, creating a short circuit between the top cover and the connecting piece, prompting the battery to discharge rapidly to a low charge level, thereby reducing the battery's charge. When the temperature of the battery cell further rises to the thermal runaway temperature, even if thermal runaway is triggered, the low charge level significantly reduces the risk of fire and explosion. Simultaneously, it avoids the phenomenon of the top cover deforming due to excessively high thermal runaway temperatures, causing a short circuit between the top cover and the positive / negative electrode connecting pieces, thus improving battery safety and reducing the risk of thermal runaway propagation from the battery cell. A detailed description follows with reference to the accompanying drawings.

[0036] like Figure 1 As shown, the battery cell 100 has two intersecting directions that are perpendicular to the first direction Z, the second direction X, and the third direction Y. The first direction Z is the height direction of the battery cell 100, the second direction X is the length direction of the battery cell 100, and the third direction Y is the width direction of the battery cell 100.

[0037] The battery cell 100 includes, but is not limited to, lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and this disclosure does not limit this type. The battery pack is the power supply for the electrical device. The electrical device can be a mobile phone, portable device, laptop, electric vehicle, electric car, ship, spacecraft, electric toy, and power tool, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0038] like Figure 1 and Figure 2 As shown, the battery cell 100 includes a housing 1, an electrode assembly 2, a top cover 3, an insulating component 4, a connecting piece 5, and a resistor 6.

[0039] The housing 1 has a receiving cavity (not shown) and an opening 11 communicating with the receiving cavity. The electrode assembly 2 is disposed in the receiving cavity of the housing 1, which can provide a good working environment for the electrode assembly 2 and other important structures in the battery. The housing 1 plays a certain role in protecting these structures and preventing them from being damaged by external factors.

[0040] like Figure 2 As shown, the top cover 3 is connected to the housing 1 along the first direction Z. Specifically, the top cover 3 is used to close the opening 11 of the housing 1 so that the housing 1 forms a sealed space.

[0041] like Figure 2 As shown, the insulating component 4 is disposed inside the housing 1, and is located on the side of the top cover 3 near the electrode assembly 2. Specifically, the insulating component 4 can be a lower plastic, which is disposed between the top cover 3 and the connecting piece 5 to achieve insulation between the two.

[0042] like Figure 2 As shown, the connecting piece 5 is disposed within the housing 1 and is electrically connected to the electrode assembly 2. The battery cell 100 also includes a terminal post 7, and the connecting piece 5 is used to connect the electrode assembly 2 and the terminal post 7. The connecting piece 5 provides a low-resistance path 6, allowing current to be efficiently conducted from the electrode assembly 2 to the terminal post 7, thereby improving the overall performance of the battery. Furthermore, the connecting piece 5 helps to evenly distribute the heat generated inside the battery, reducing the risk of localized overheating and thus extending the battery's lifespan.

[0043] In some embodiments, such as Figure 2As shown, the electrode assembly 2 has an electrode body 21 and a tab 22, with the tab 22 connected to the electrode body 21 in the first direction Z. The battery cell 100 also includes a terminal post 7, which is arranged at intervals with resistors 6 along the second direction X. There are multiple resistors 6, which are located at both ends of the top cover 3 along the second direction X. The terminal post 7 is located between two adjacent resistors 6, which reduces the length of the current transmission path, thereby reducing resistor loss and improving the energy efficiency of the battery.

[0044] Understandably, the connecting piece 5 may include a positive connecting piece and a negative connecting piece, the tab 22 may include a positive tab and a negative tab, and the terminal 7 may include a positive terminal and a negative terminal. The positive tab is connected to the positive terminal via the positive connecting piece, and the negative tab is connected to the negative terminal via the negative connecting piece. Therefore, the positive and negative connecting pieces provide a clear current path, enabling current to be effectively conducted from the electrode assembly 2 to the corresponding terminal 7, ensuring the normal charging and discharging function of the battery.

[0045] like Figure 2 As shown, the first end of resistor 6 is connected to the top cover 3, and the second end of resistor 6 passes through the insulating member 4 and is connected to the connecting piece 5 along the first direction Z. It can be understood that the insulating member 4 has a through hole for mounting resistor 6 and can achieve the insulation effect between the top cover 3 and the connecting piece 5.

[0046] Resistor 6 can be a negative temperature coefficient thermistor (NTC). NTC thermistors utilize functional materials with extremely high resistivity at low or room temperature, extremely low resistivity at high temperature, and strong overcurrent capability, such as metal oxides like manganese oxide, cobalt oxide, and nickel oxide, and semiconductor crystals like germanium and silicon, but are not limited to these two types. Within the specified operating temperature range of -10℃ to 60℃ for the battery cell 100, the NTC resistance is >0.5MΩ, indicating it is in an insulating state.

[0047] Therefore, when the internal temperature of the battery cell 100 reaches above 100°C, the NTC resistance is ≤10Ω. The resistor 6 connected between the top cover 3 and the connecting piece 5 conducts the two, so that the top cover 3, the negative electrode connecting piece 5, and the positive electrode connecting piece 5 form a short circuit loop, which discharges the battery (such as a lithium-ion battery) quickly, and the NTC operating temperature is above 1000°C.

[0048] In some embodiments, such as Figure 3As shown, one of the top cover 3 and the resistor 6 has a first mating part 31, and the other has a second mating part 61 for the first mating part 31 to engage with. Through the snap-fit ​​design of the first mating part 31 and the second mating part 61, a stable connection is formed between the top cover 3 and the resistor 6, reducing relative movement between components and improving the overall structural stability of the battery. Furthermore, this mating design simplifies the battery assembly process, enabling components to be quickly and accurately positioned and connected, thus improving production efficiency.

[0049] In some embodiments, such as Figure 3 As shown, one of the connecting piece 5 and the resistor 6 is provided with a third mating part 51, which is disposed opposite to the first mating part 31 along the first direction Z. The other is provided with a fourth mating part 62 for the third mating part 51 to engage. Through the snap-fit ​​design of the third mating part 51 and the fourth mating part 62, a stable connection is formed between the top cover 3 and the resistor 6, reducing relative movement between components and improving the overall structural stability of the battery. Furthermore, this mating design simplifies the battery assembly process, enabling components to be quickly and accurately positioned and connected, thus improving production efficiency.

[0050] The aforementioned "the third mating part 51 and the first mating part 31 are arranged opposite each other along the first direction Z" is equivalent to the first mating part 31, the second mating part 61, the third mating part 51 and the fourth mating part 62 being located on the same straight line in the first direction Z. In this way, when the battery cell 100 experiences thermal runaway, the thermally runaway battery cell 100 can quickly form a short circuit circuit, thereby quickly discharging the battery and enhancing the safety and reliability of the battery.

[0051] In some embodiments, such as Figures 2 to 8 As shown, one of the first mating part 31 and the second mating part 61 is configured as a groove, and the other of the first mating part 31 and the second mating part 61 is configured as a protrusion; and / or, one of the third mating part 51 and the fourth mating part 62 is configured as a groove, and the other of the third mating part 51 and the fourth mating part 62 is configured as a protrusion. Several examples are given below to explain the above.

[0052] In the first example, such as Figure 3 As shown, the first mating part 31 is a protrusion, and the second mating part 61 is a groove; the first mating part 31 protrudes towards the electrode assembly 2, and the second mating part 61 is recessed along the first direction Z towards the electrode assembly 2, with the first mating part 31 located within the second mating part 61. The third mating part 51 is a protrusion, and the fourth mating part 62 is a groove; the third mating part 51 protrudes away from the electrode assembly 2, and the fourth mating part 62 is recessed away from the electrode assembly 2, with the third mating part 51 located within the fourth mating part 62.

[0053] like Figure 3 and Figure 4 As shown, the resistor 6 includes at least two first main body portions 601 and at least one connecting portion 602. The two ends of the first main body portions 601 are inserted through the insulating member 4 along the first direction Z. The connecting portion 602 is connected between the two first main body portions 601 along a direction perpendicular to the first direction Z, and forms a second mating portion 61 and a fourth mating portion 62 that are spaced apart along the connecting portion 602 with the two first main body portions 601.

[0054] It is understandable that the cross-sectional view of resistor 6 is "H" shaped. With the connecting part 602 as the boundary, the upper surface of the connecting part 602 and the upper half of the two main body parts form the second mating part 61, and the lower surface of the connecting part 602 and the lower half of the two main body parts form the fourth mating part 62. Optionally, multiple first main body parts 601 form a column with a cavity 10, and the connecting part 602 is disposed in the cavity 10 to divide the column into two grooves (i.e., the second mating part 61 and the fourth mating part 62). These two grooves are symmetrically arranged in the first direction Z and the second direction, which facilitates the improvement of the installation efficiency of resistor 6.

[0055] In the second example, such as Figure 5 and Figure 6 As shown, the first mating part 31 is a groove, and the second mating part 61 is a protrusion; the first mating part 31 is recessed towards the electrode assembly 2, and the second mating part 61 protrudes towards the electrode assembly 2 along the first direction Z, and the second mating part 61 is located inside the first mating part 31. The third mating part 51 is a groove, and the fourth mating part 62 is a protrusion; the third mating part 51 is recessed away from the electrode assembly 2, and the fourth mating part 62 protrudes away from the electrode assembly 2, and the fourth mating part 62 is located inside the third mating part 51.

[0056] like Figure 6 As shown, the resistor 6 includes a second mating part 61, a second main body part 603 and a fourth mating part 62 connected sequentially along the first direction Z. The two ends of the second main body part 603 are inserted through the insulating member 4 along the first direction Z. The second mating part 61 is connected to the end of the second main body part 603 away from the electrode assembly 2, and the fourth mating part 62 is connected to the end of the second main body part 603 near the electrode assembly 2.

[0057] It is understandable that the resistor 6 has a "+" shaped cross-section in the first direction Z. The first mating part 31 protrudes from the upper end face of the second main body 603, and the fourth mating part 62 protrudes from the lower end face of the second main body 603. The first mating part 31 and the fourth mating part 62 are symmetrically arranged in the first direction Z and the second direction, which facilitates the improvement of the installation efficiency of the resistor 6.

[0058] In the third example, such as Figure 7As shown, the first mating part 31 is a protrusion, and the second mating part 61 is a groove; the first mating part 31 protrudes towards the electrode assembly 2, and the second mating part 61 is recessed along the first direction Z towards the electrode assembly 2, with the first mating part 31 located within the second mating part 61. The third mating part 51 is a groove, and the fourth mating part 62 is a protrusion; the third mating part 51 is recessed away from the electrode assembly 2, and the fourth mating part 62 protrudes away from the electrode assembly 2, with the fourth mating part 62 located within the third mating part 51.

[0059] In the fourth example, such as Figure 8 As shown, the first mating part 31 is a groove, and the second mating part 61 is a protrusion; the first mating part 31 is recessed towards the electrode assembly 2, and the second mating part 61 protrudes towards the electrode assembly 2 along the first direction Z, and the second mating part 61 is located inside the first mating part 31. The third mating part 51 is a protrusion, and the fourth mating part 62 is a groove; the third mating part 51 protrudes away from the electrode assembly 2, and the fourth mating part 62 is recessed away from the electrode assembly 2, and the third mating part 51 is located inside the fourth mating part 62.

[0060] In the four examples above, resistor 6 in the first and second examples has a symmetrical structure, while resistor 6 in the third and fourth examples has an asymmetrical structure. Although the structural forms of these four examples are different, in all four examples, resistor 6 remains in an insulating state during the normal use of the battery cell 100. That is, the top cover 3 and the connecting piece 5 are insulated from each other, and a conductive path cannot be formed, thus not affecting the normal operation of the battery. When the temperature of the battery cell 100 continues to rise, the heat transfer will first cause resistor 6 to reach the conduction temperature, so that the top cover 3 and the connecting piece 5 are electrically connected and a short circuit is formed, prompting the battery to discharge rapidly to a low charge, thereby reducing the battery's charge level. When the temperature of the battery cell 100 further rises to the thermal runaway temperature, even if thermal runaway of the battery cell 100 is triggered, the low charge level at this time can significantly reduce the risk of fire and explosion. At the same time, it also avoids the phenomenon that the top cover 3 deforms due to excessively high thermal runaway temperature, causing the top cover 3 to short-circuit with the positive / negative terminal connecting piece 5 and generate sparks, thereby improving the safety of battery use and reducing the risk of thermal runaway of the battery cell 100 spreading.

[0061] The general shape of the resistor 6 can be a cylinder, a cube, a cuboid, etc., and no special limitation is made here.

[0062] In some embodiments, the projected area of ​​resistor 6 along the first direction Z on connector 5 is less than or equal to one-third of the area of ​​connector 5. This reduces the impact of resistor 6 on the entire connector 5, thereby reducing resistance loss in the current transmission path and improving battery energy efficiency. Furthermore, it helps optimize current distribution on connector 5, reducing the risk of localized overheating and improving battery thermal management performance.

[0063] like Figure 1 and Figure 2 As shown, from Figure 1 As can be seen, both resistors 6 are cylinders with a height of, for example, 1.5 mm. The projected area of ​​resistor 6 along the first direction Z on the connecting piece 5 is, for example, 78.5 mm². The first mating part 31, the second mating part 61, the third mating part 51, and the fourth mating part 62 are all cylinders with a height of, for example, 0.5 mm. The projected area of ​​the first mating part 31 and the third mating part 51 along the first direction Z on the connecting piece 5 is, for example, 50.24 mm². When the temperature of the battery cell 100 exceeds 100°C, the resistance of 6 drops to 20 mΩ, and the connecting piece 5 of the lithium-ion battery cell is connected to the top cover 3 to form a short circuit, which discharges rapidly, reducing the energy during thermal runaway of the lithium-ion battery cell and lowering the maximum thermal runaway temperature of the lithium-ion battery cell by about 30%.

[0064] In the above embodiments, the resistor 6 connected to the positive terminal connector can be a positive terminal resistor (e.g., the left resistor), and the resistor 6 connected to the negative terminal connector can be a negative terminal resistor (e.g., the right resistor). Figure 2 and Figure 5 As shown, in these two embodiments, the structure of the positive resistor can be the same as that of the negative resistor, which helps to improve assembly efficiency. Figure 9 As shown, in this embodiment, the structure of the positive resistor can be different from the structure of the negative resistor. Figure 2 and Figure 5 Compared to the embodiment shown, the assembly efficiency of this embodiment is slightly more complicated.

[0065] like Figure 10As shown, this application embodiment also provides a battery pack, including multiple battery cells 100 as described above, a housing 200, and a cover 300. The multiple battery cells 100 are disposed within the housing 200 and arranged to form a battery module. The cover 300 closes to the opening 11 of the housing 200 to seal the opening 11. In this battery pack, the heat of a single battery cell 100 continuously rises. The heat transfer first causes the resistor 6 to reach its conduction temperature, thus forming a short circuit between the top cover 3 and the connecting piece 5, causing the battery to discharge rapidly to a low charge level, thereby reducing the battery's charge. When the temperature of the battery cell 100 further rises to the thermal runaway temperature, even if thermal runaway of the battery cell 100 is triggered, the low charge level at this time significantly reduces the risk of fire and explosion. Simultaneously, it avoids the phenomenon where excessively high thermal runaway temperatures cause the top cover 3 to deform, resulting in a short circuit between the top cover 3 and the positive / negative electrode connecting piece 5, generating sparks. This improves the safety of battery use and reduces the risk of thermal runaway propagation from the battery cell 100.

[0066] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0067] The foregoing has provided a detailed description of a battery cell, battery pack, and electrical device provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, characterized by, The battery cell has a first orientation, and the battery cell includes: case; Electrode assembly, disposed within the housing; The top cover is connected to the housing along the first direction; An insulating element is disposed within the housing, and the insulating element is located on the side of the top cover near the electrode assembly; A connecting piece, disposed within the housing, is electrically connected to the electrode assembly; and A resistor, the first end of which is connected to the top cover, and the second end of which passes through the insulating member along the first direction and is connected to the connecting piece; one of the top cover and the resistor is provided with a first mating part, and the other is provided with a second mating part for the first mating part to engage.

2. The battery cell of claim 1, wherein, The first mating part is a protrusion, and the second mating part is a groove; the first mating part protrudes towards the electrode assembly, and the second mating part is recessed towards the electrode assembly along the first direction, with the first mating part located within the second mating part.

3. The battery cell according to claim 1, characterized in that, The first mating part is a groove, and the second mating part is a protrusion; the first mating part is recessed in the direction of approaching the electrode assembly, and the second mating part protrudes in the direction of approaching the electrode assembly along the first direction, and the second mating part is located inside the first mating part.

4. The battery cell according to claim 3, characterized in that, One of the connecting piece and the resistor is provided with a third mating part, which is arranged opposite to the first mating part along the first direction, and the other is provided with a fourth mating part for the third mating part to engage.

5. The battery cell according to claim 4, characterized in that, The third mating part is configured as a protrusion, and the fourth mating part is configured as a groove. The third mating part protrudes in the direction away from the electrode assembly, and the fourth mating part is recessed in the direction away from the electrode assembly. The third mating part is located within the fourth mating part.

6. The battery cell according to claim 5, characterized in that, The resistor includes at least two first main bodies and a connecting portion. The two ends of the first main bodies are inserted through the insulating member along the first direction. The connecting portion is connected to two adjacent first main bodies to form a second mating portion and a fourth mating portion. The second mating portion and the fourth mating portion are spaced apart along the first direction.

7. The battery cell according to claim 4, characterized in that, The third mating part is a groove, and the fourth mating part is a protrusion. The third mating part is recessed in the direction away from the electrode assembly, and the fourth mating part is protruding in the direction away from the electrode assembly. The fourth mating part is located inside the third mating part.

8. The battery cell according to claim 7, characterized in that, The resistor includes a second mating portion, a second main body portion, and a fourth mating portion connected sequentially along the first direction. The two ends of the second main body portion are inserted through the insulating member along the first direction. The second mating portion is connected to one end of the second main body portion away from the electrode assembly, and the fourth mating portion is connected to one end of the second main body portion near the electrode assembly.

9. The battery cell according to claim 1, characterized in that, The battery cell also has a second direction perpendicular to the first direction. The electrode assembly has a tab portion, which is connected to the electrode body in the first direction; The battery cell also includes a terminal post that passes through the top cover. The connecting piece connects the terminal post and the tab in the first direction. The terminal post and the resistor are arranged at intervals along the second direction. There are multiple resistors. The multiple resistors are arranged at both ends of the top cover along the second direction. The terminal post is located between two adjacent resistors.

10. A battery pack, characterized in that, include: The battery cell as described in any one of claims 1 to 9.

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