Single battery, battery pack and electric equipment
By setting up a staggered diaphragm layer structure with different cutoff temperatures in the single cell, the control short circuit occurs in a fixed area and preferentially dissipate heat through large surfaces, the problem of thermal runaway in the single cell is solved, the duration of thermal runaway is extended, and the safety and thermal management efficiency of the single cell are improved.
Patent Information
- Application Number
- CN202422137400.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-30
- Publication Date
- 2025-08-01
- Estimated Expiration
- 2034-08-30
AI Technical Summary
When the temperature is too high, the existing single-cell batteries are prone to rapid overall thermal runaway, resulting in short-circuit between the positive electrode plate and the negative electrode plate, causing thermal runaway.
The first diaphragm layer and the second diaphragm layer with different cutoff temperatures are arranged interlaced. The cutoff temperature of the first diaphragm layer is higher than that of the second diaphragm layer, ensuring that when the temperature of the single cell rises, the second diaphragm layer first melts, and then the first diaphragm layer melts, controlling the short circuit to occur in a fixed area and dissipate heat through a large surface, extending the duration of thermal runaway.
By controlling short circuits and heat dissipation in segments, the duration of thermal runaway is extended, the risk of single batteries is reduced, safety is improved, and thermal management is facilitated by the battery management system.
Smart Images
Figure CN223181324U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the technical field of batteries, and particularly relates to a single battery, a battery pack, and an electrical device. Background Art
[0002] At present, a single battery usually includes a positive electrode sheet and a negative electrode sheet, and a separator layer is arranged between the positive electrode sheet and the negative electrode sheet for insulation. When the temperature of the single battery is too high, the separator layer will shrink and melt due to heat, resulting in the contact short circuit between the positive electrode sheet and the negative electrode sheet, and then causing the single battery to quickly have an overall thermal runaway. Summary of the Utility Model
[0003] Purpose of this application: This application provides a single battery, which is used to solve the problem that when the temperature of the single battery is too high, the single battery quickly has an overall thermal runaway; this application also provides a battery pack; this application also provides an electrical device.
[0004] Technical solution: This application provides a single battery, including:
[0005] A housing and an electrode assembly arranged inside the housing; the electrode assembly includes a plurality of first type electrode sheets and a plurality of second type electrode sheets arranged in a staggered and stacked manner along a first direction X;
[0006] A plurality of first separator layers, the first separator layers are arranged between at least one of the first type electrode sheets and at least one of the second type electrode sheets adjacent to each other;
[0007] A plurality of second separator layers, the second separator layers are arranged between at least one of the first type electrode sheets and at least one of the second type electrode sheets adjacent to each other, and the second separator layers are arranged on both sides of the first separator layers along the first direction X;
[0008] Wherein, the cut-off temperature of the first separator layer is T1, the cut-off temperature of the second separator layer is T2, and the single battery satisfies: T1 > T2.
[0009] In some embodiments, the number of the first separator layers is equal to the number of the second separator layers.
[0010] In some embodiments, the single battery includes a middle region, and two edge regions arranged on both sides of the middle region along the first direction X; the first separator layers are arranged in the middle region, and the second separator layers are arranged in the edge regions.
[0011] In some embodiments, the number of the second separator layers in the two edge regions is equal.
[0012] In some embodiments, the single battery satisfies:
[0013] 1.23 ≥ T1 / T2 ≥ 1.07.
[0014] In some embodiments, the cut-off temperature of the first separator layer ranges from 150 to 160 °C.
[0015] In some embodiments, the cut-off temperature of the second separator layer ranges from 130 to 140 °C.
[0016] In some embodiments, the first separator layer and the second separator layer each include and are not both any one of a polyethylene separator layer, a polypropylene separator layer, a polyimide separator layer, a polyester separator layer, a non-woven separator, and a ceramic-coated separator.
[0017] Correspondingly, the present application further provides a battery pack including the single battery as described in any one of the above embodiments.
[0018] Correspondingly, the present application further provides an electrical device including the battery pack as described in the above embodiments.
[0019] Advantageous effects: Compared with the prior art, a single battery provided by an embodiment of the present application, by disposing the first separator layer between at least one first type of electrode and at least one second type of electrode adjacent to each other, and disposing the second separator layer between at least one first type of electrode and at least one second type of electrode adjacent to each other, and the second separator layer is arranged on both sides of the first separator layer along the first direction X; the cut-off temperature of the first separator layer is T1, and the cut-off temperature of the second separator layer is T2, and the single battery satisfies: T1 > T2. When the temperature of the single battery is too high, due to the lower cut-off temperature, the second separator layer will first contract and melt, resulting in the first type of electrode and the second type of electrode on both sides of the second separator layer coming into contact and short-circuiting to generate heat, and the single battery releases heat in the first stage at the position where the second separator layer is disposed. After a period of time, as the temperature of the single battery continues to rise, the first separator layer with a higher cut-off temperature will then contract and melt, resulting in the first type of electrode and the second type of electrode on both sides of the first separator layer coming into contact and short-circuiting to generate heat, avoiding the simultaneous contraction of the first separator layer and the second separator layer, and the single battery releases heat in the second stage at the position where the first separator layer is disposed, prolonging the duration of thermal runaway of the single battery and improving the safety of the single battery.
[0020] It can be understood that, compared with the prior art, a battery pack provided by an embodiment of the present application includes all the technical features and technical effects of the above single battery, which will not be elaborated herein.
[0021] It can be understood that, compared with the prior art, an electrical device provided by an embodiment of the present application includes all the technical features and technical effects of the above battery pack, which will not be elaborated herein. Description of the Drawings
[0022] The following will, in conjunction with the accompanying drawings, clearly and completely describe the technical solutions in the embodiments of the present application through a detailed description of the specific embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present application.
[0023] Figure 1 It is the first structural schematic diagram of the single cell provided by the embodiment of the present application;
[0024] Figure 2 It is the second structural schematic diagram of the single cell provided by the embodiment of the present application;
[0025] Figure 3 It is the third structural schematic diagram of the single cell provided by the embodiment of the present application;
[0026] Figure 4 It is the fourth structural schematic diagram of the single cell provided by the embodiment of the present application;
[0027] Figure 5 It is the first short - circuit schematic diagram of the single cell provided by the embodiment of the present application;
[0028] Figure 6 It is the second short - circuit schematic diagram of the single cell provided by the embodiment of the present application.
[0029] Reference numerals: 10 - housing; 20 - electrode assembly; 21 - first - type electrode plate; 22 - second - type electrode plate; 30 - first separator layer; 40 - second separator layer; 50 - intermediate region; 60 - edge region; X - first direction. Specific Embodiments
[0030] The following will, in conjunction with the accompanying drawings in the embodiments of the present application, clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present application.
[0031] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, an electrical connection, or a connection that allows mutual communication; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances. In the description of the present application, "a plurality of" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features.
[0032] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present application.
[0033] Please refer to Figure 1 , Figure 1Schematically shows a first structural schematic diagram of a single cell provided by an embodiment of the present application. The present application provides a single cell, including: a housing 10, an electrode assembly 20 disposed inside the housing 10, a plurality of first separator layers 30, and a plurality of second separator layers 40; the electrode assembly 20 includes a plurality of first type electrode plates 21 and a plurality of second type electrode plates 22 arranged in a staggered and stacked manner along a first direction X, the plurality of first type electrode plates 21 are electrically connected to each other, and the plurality of second type electrode plates 22 are electrically connected to each other; the first type electrode plates 21 and the second type electrode plates 22 have different polarities; the first separator layer 30 is disposed between at least one adjacent first type electrode plate 21 and at least one second type electrode plate 22; the second separator layer 40 is disposed between at least one adjacent first type electrode plate 21 and at least one second type electrode plate 22, and the second separator layer 40 is arranged on both sides of the first separator layer 30 along the first direction X; wherein, the cut-off temperature of the first separator layer 30 is T1, and the cut-off temperature of the second separator layer 40 is T2, and the single cell satisfies: T1 > T2. In the embodiment of the present application, the different polarities of the first type electrode plates 21 and the second type electrode plates 22 mean that when the first type electrode plates 21 are positive electrode plates, the second type electrode plates 22 are negative electrode plates, or when the first type electrode plates 21 are negative electrode plates, the second type electrode plates 22 are positive electrode plates. Thus, by providing the first separator layer 30 and the second separator layer 40, when the temperature of the single cell is too high, due to the lower cut-off temperature, the second separator layer 40 will first shrink and melt, causing the first type electrode plates 21 and the second type electrode plates 22 on both sides of the second separator layer 40 to contact and short-circuit and generate heat, and the single cell releases heat in the first stage at the position where the second separator layer 40 is provided. After a period of time, as the temperature of the single cell continues to rise, the first separator layer 30 with a higher cut-off temperature will then shrink and melt, causing the first type electrode plates 21 and the second type electrode plates 22 on both sides of the first separator layer 30 to contact and short-circuit and generate heat, preventing the first separator layer 30 and the second separator layer 40 from shrinking simultaneously, and the single cell releases heat in the second stage at the position where the first separator layer 30 is provided, prolonging the duration of thermal runaway of the single cell and improving the safety of the single cell.
[0034] It should be noted that the cut-off temperatures of the first separator layer 30 and the second separator layer 40 in the present application may refer to the melting point, but not only the melting point. The melting point is just one type of cut-off temperature. Specifically, the cut-off temperature refers to the temperature at which a certain process, reaction, system, or device reaches and stops at a certain specific state, and the melting point is the fixed temperature at which a substance changes from a solid state to a liquid state. Therefore, the melting point can be regarded as the cut-off temperature of the phase change of a substance from a solid state to a liquid state. That is to say, in some embodiments, the cut-off temperatures of the first separator layer 30 and the second separator layer 40 in the present application may be the melting point, but in some embodiments, the cut-off temperatures of the first separator layer 30 and the second separator layer 40 in the present application may also not be the melting point, as long as it can be achieved that when the separator layer reaches the cut-off temperature, the first type electrode plates 21 and the second type electrode plates 22 on both sides contact and short-circuit and generate heat.
[0035] Specifically, please refer to Figure 1 and also refer to Figure 5 and Figure 6 , Figure 5 which schematically shows the first short - circuit diagram of the single - cell battery provided by the embodiment of the present application; Figure 6 which schematically shows the second short - circuit diagram of the single - cell battery provided by the embodiment of the present application. In the embodiment of the present application, the cut - off temperatures of the first separator layer 30 and the second separator layer 40 are different, that is, the cut - off temperatures of the first separator layer 30 and the second separator layer 40 are different, so as to ensure that the second separator layer 40 and the first separator layer 30 shrink in sequence after being affected by high temperature. When the temperature of the single - cell battery begins to rise, due to the lower cut - off temperature, the second separator layer 40 first shrinks and melts, resulting in the contact short - circuit and heat generation between the first - type electrode sheets 21 and the second - type electrode sheets 22 on both sides of the second separator layer 40, and the single - cell battery releases heat in the first stage at the position where the second separator layer 40 is arranged. Since the second separator layer 40 is arranged on both sides of the first separator layer 30 along the first direction X and is closer to the large surface of the single - cell battery, the heat generated by the short - circuit of the second separator layer 40 can be quickly dissipated through the large surface of the single - cell battery. At this time, if the temperature of the single - cell battery decreases, the single - cell battery will not undergo further thermal runaway, which is equivalent to controlling the position of the thermal runaway of the single - cell battery at the position corresponding to the second separator layer 40 where heat dissipation is convenient, avoiding short - circuits at random positions inside the single - cell battery and improving the safety of the single - cell battery. If the temperature of the single - cell battery does not decrease in the first stage, when the temperature of the single - cell battery continues to rise, the first separator layer 30 with a higher cut - off temperature continues to shrink and melt, resulting in the contact short - circuit and heat generation between the first - type electrode sheets 21 and the second - type electrode sheets 22 on both sides of the first separator layer 30, and the single - cell battery releases heat in the second stage at the position where the first separator layer 30 is arranged. At this time, the heat needs to be dissipated through the first separator layer 30 and the second separator layer 40 and then through the housing 10, or through the first separator layer 30 and then through the housing 10. In this way, by setting the first separator layer 30 and the second separator layer 40, the short - circuit occurs in a fixed area of the single - cell battery and preferentially dissipates heat through the large surface of the single - cell battery. At the same time, by setting the first separator layer 30 and the second separator layer 40, the short - circuit of the single - cell battery is presented in a segmented form, reducing the short - circuit resistance of the single - cell battery, thereby slowing down the heat generation rate after the short - circuit of the single - cell battery and facilitating the thermal management of the battery management system. In addition, controlling the single - cell battery to release heat in two stages prolongs the duration of thermal runaway of the single - cell battery, so as to increase the reaction operation time for the thermal runaway of the single - cell battery, reduce the risk of the single - cell battery, and improve the safety of the single - cell battery.
[0036] Please refer to Figure 1, in some embodiments, the number of the first diaphragm layers 30 is equal to the number of the second diaphragm layers 40. It can be understood that the number of the first diaphragm layers 30 determines the heat release volume of the single battery in the first stage, and the number of the second diaphragm layers 40 determines the heat release volume of the single battery in the second stage. When the number of the first diaphragm layers 30 is equal to the number of the second diaphragm layers 40, the volume of the single battery for heat release in the two stages can be evenly divided, so as to reasonably utilize the internal space of the single battery and improve the safety of the single battery.
[0037] It can be understood that, please refer to Figure 3 and Figure 4 , Figure 3 which schematically shows a third structural diagram of the single battery provided by the embodiment of the present application; Figure 4 which schematically shows a fourth structural diagram of the single battery provided by the embodiment of the present application; The embodiment of the present application can also adjust the number of the first diaphragm layers 30 and the number of the second diaphragm layers 40 for different types of single batteries, so as to adjust the volume of the single battery for heat generation in the first stage and the volume for heat generation in the second stage.
[0038] Please refer to Figure 1 again, and refer to Figure 2 , Figure 2Schematically shows a second structural schematic diagram of a single battery provided by an embodiment of the present application. In some embodiments, the single battery includes an intermediate region 50, and two edge regions 60 disposed on both sides of the intermediate region 50 along the first direction X; the first separator layer 30 is disposed in the intermediate region 50, and the second separator layer 40 is disposed in the edge region 60. In the embodiment of the present application, the intermediate region 50 includes a plurality of first-type electrode sheets 21 and a plurality of second-type electrode sheets 22 stacked in the middle of the electrode assembly 20, and the edge region 60 is close to the large surface of the housing 10. The edge region 60 includes a plurality of first-type electrode sheets 21 and a plurality of second-type electrode sheets 22 disposed close to the housing 10 in the electrode assembly 20. Thus, by disposing the second separator layer 40 in the edge region 60, when the temperature of the single battery begins to rise, the second separator layer 40 with a lower cut-off temperature first shrinks and melts, causing the first-type electrode sheets 21 and the second-type electrode sheets 22 on both sides of the second separator layer 40 to contact and short-circuit and generate heat. The single battery releases heat in the first stage at the position where the second separator layer 40 is disposed, and the heat is dissipated through the large surface of the housing 10. Similarly, by disposing the first separator layer 30 in the intermediate region 50, when the temperature of the single battery continues to rise, the first separator layer 30 with a higher cut-off temperature shrinks and melts, causing the first-type electrode sheets 21 and the second-type electrode sheets 22 on both sides of the first separator layer 30 to contact and short-circuit and generate heat. The single battery releases heat in the second stage at the position where the first separator layer 30 is disposed, and the heat is dissipated through the large surface and the small surface of the housing 10 at the same time. Thus, by providing the edge region 60 and the intermediate region 50, the short circuit of the single battery occurs in a fixed region, and through the two-stage heat dissipation of the edge region 60 and the intermediate region 50, the duration of thermal runaway of the single battery is extended, the risk of thermal runaway of the single battery is further reduced, and the safety of the single battery is improved.
[0039] Please refer to again Figure 2 , in some embodiments, the number of the second separator layers 40 in the two edge regions 60 is equal. Specifically, the two edge regions 60 correspond to the two large surfaces of the single battery. Therefore, by setting the same number of the second separator layers 40 in the two edge regions 60, when the second separator layer 40 is heated and causes contraction and fusing, resulting in the first-type electrode sheets 21 and the second-type electrode sheets 22 on both sides of the first separator layer 30 to contact and short-circuit, the generated heat can be evenly dissipated through the two large surfaces of the single battery at the same time, avoiding excessive heat generation by the second separator layer 40 corresponding to the single large surface of the single battery and being difficult to dissipate in time, and improving the heat dissipation efficiency of the single battery through the two large surfaces.
[0040] In some embodiments, the single cell satisfies: 1.23 ≥ T1 / T2 ≥ 1.07. In the embodiments of the present application, the cut-off temperature of the first separator layer 30 is T1, and the cut-off temperature of the second separator layer 40 is T2. Considering that the difference between T1 and T2 should not be too large to avoid the first separator layer 30 not taking effect in time, and the difference between T1 and T2 should not be too small to avoid too short an effective time of the second separator layer 40, the upper and lower limit values of T1 / T2 are set in the present application. By limiting T1 / T2 ≥ 1.07, the longest effective time of the second separator layer 40 is controlled, so that the first separator layer 30 takes effect in time, ensuring that the single cell can release heat in two stages through the first separator layer 30 and the second separator layer 40 when the temperature is continuously rising. By limiting 1.23 ≥ T1 / T2, the shortest effective time of the second separator layer 40 is controlled, so that the second separator layer 40 maintains a certain effective time, that is, ensuring that the single cell can release heat in two stages through the first separator layer 30 and the second separator layer 40 when the temperature is continuously rising, so as to extend the thermal runaway time of the single cell and improve the safety of the single cell.
[0041] In the embodiments of the present application, the single cell satisfies: the temperature range of the cut-off temperature of the first separator layer 30 is 150 to 160 °C. For example, the temperature of the cut-off temperature of the first separator layer 30 can be any value or a value between any two values among 150 °C, 151 °C, 152 °C, 153 °C, 154 °C, 155 °C, 156 °C, 157 °C, 158 °C, 159 °C, 160 °C.
[0042] In the embodiments of the present application, the single cell satisfies: the temperature range of the cut-off temperature of the second separator layer 40 is 130 to 140 °C. For example, the temperature of the cut-off temperature of the first separator layer 30 can be any value or a value between any two values among 130 °C, 131 °C, 132 °C, 133 °C, 134 °C, 135 °C, 136 °C, 137 °C, 138 °C, 139 °C, 140 °C.
[0043] In some embodiments, the first separator layer 30 and the second separator layer 40 respectively include, and are not simultaneously, any one of a polyethylene (PE) separator layer, a polypropylene (PP) separator layer, a polyimide (PI) separator layer, a polyester (PET) separator layer, a non-woven fabric separator, and a ceramic-coated separator. That is, the first separator layer 30 can be any one of a polyethylene separator layer, a polypropylene separator layer, a polyimide separator layer, a polyester separator layer, a non-woven fabric separator, and a ceramic-coated separator, and the second separator layer 40 can also be any one of a polyethylene separator layer, a polypropylene separator layer, a polyimide separator layer, a polyester separator layer, a non-woven fabric separator, and a ceramic-coated separator. And it should be ensured that the first separator layer 30 and the second separator layer 40 are different from each other to achieve different cut-off temperatures for the first separator layer 30 and the second separator layer 40, control the monomer battery to release heat in two stages through the sequential shrinkage of the second separator layer 40 and the first separator layer 30, extend the thermal runaway duration of the monomer battery, so as to increase the reaction operation time for the thermal runaway of the monomer battery, reduce the risk of the monomer battery, and improve the safety of the monomer battery.
[0044] In summary, a monomer battery provided by an embodiment of the present application includes: a housing 10, an electrode assembly 20 disposed inside the housing 10, a plurality of first separator layers 30, and a plurality of second separator layers 40; the electrode assembly 20 includes a plurality of first-type electrode sheets 21 and a plurality of second-type electrode sheets 22 arranged in a staggered and stacked manner along the first direction X, the plurality of first-type electrode sheets 21 are electrically connected to each other, and the plurality of second-type electrode sheets 22 are electrically connected to each other; the polarities of the first-type electrode sheets 21 and the second-type electrode sheets 22 are different; the first separator layer 30 is disposed between at least one adjacent first-type electrode sheet 21 and at least one second-type electrode sheet 22; the second separator layer 40 is disposed between at least one adjacent first-type electrode sheet 21 and at least one second-type electrode sheet 22, and the second separator layer 40 is arranged on both sides of the first separator layer 30 along the first direction X; wherein, the cut-off temperature of the first separator layer 30 is T1, and the cut-off temperature of the second separator layer 40 is T2, and the monomer battery satisfies: T1 > T₂. In this way, by providing the first separator layer 30 and the second separator layer 40, the short circuit occurs in a fixed area of the monomer battery, and heat dissipation is preferentially carried out through the large surface of the monomer battery. At the same time, by providing the first separator layer 3 and the second separator layer 40, the short circuit of the monomer battery is presented in a segmented form, reducing the short-circuit resistance of the monomer battery, thereby slowing down the heat generation rate after the short circuit of the monomer battery, which is convenient for the battery management system to perform thermal management. In addition, controlling the monomer battery to release heat in two stages extends the thermal runaway duration of the monomer battery, so as to increase the reaction operation time for the thermal runaway of the monomer battery, reduce the risk of the monomer battery, and improve the safety of the monomer battery.
[0045] Correspondingly, the present application further provides a battery pack, including the single battery in any of the above embodiments. The battery pack is used for storing and releasing electric energy, and may further include a box body and a plurality of the above battery monomers, and the plurality of battery monomers are accommodated in the box body. Among them, the battery pack may be a charge-discharge structure formed by combining a plurality of battery monomers, such as a battery module, a battery pack, a battery cluster, a battery stack, a battery tower, a battery array, etc. The battery monomer includes but is not limited to a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, a magnesium-ion battery, etc., and the embodiments of the present disclosure do not limit this.
[0046] It can be understood that, compared with the prior art, a battery pack provided by an embodiment of the present application includes all the technical features and technical effects of the above single battery, which will not be elaborated herein.
[0047] Correspondingly, the present application further provides an electrical device, including the battery pack in the above embodiment. The electrical device may be various types of devices such as a new energy vehicle, a computer, an energy storage power supply device, etc.
[0048] It can be understood that, compared with the prior art, an electrical device provided by an embodiment of the present application includes all the technical features and technical effects of the above battery pack, which will not be elaborated herein.
[0049] In the above embodiments, the descriptions of each embodiment have their own focuses. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.
[0050] The above has introduced in detail a single battery, a battery pack and an electrical device provided by the embodiments of the present application. Specific examples are used in the present application to elaborate the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A single cell, characterized in that, Comprising: A housing (10) and an electrode assembly (20) disposed inside the housing (10); the electrode assembly (20) includes a plurality of first type electrode sheets (21) and a plurality of second type electrode sheets (22) arranged in a first direction (X) and stacked in an interleaved manner; A plurality of first separator layers (30), the first separator layer (30) being disposed between at least one of the adjacent first type electrode sheets (21) and at least one of the second type electrode sheets (22); A plurality of second separator layers (40), the second separator layer (40) being disposed between at least one of the adjacent first type electrode sheets (21) and at least one of the second type electrode sheets (22), and the second separator layer (40) being arranged on both sides of the first separator layer (30) along the first direction (X); Wherein, the cut-off temperature of the first separator layer (30) is T1, the cut-off temperature of the second separator layer (40) is T2, and the single cell satisfies: T1 > T2.
2. The single cell according to claim 1, characterized in that, The number of the first separator layers (30) is equal to the number of the second separator layers (40).
3. The single cell according to claim 1, characterized in that, The single cell includes a middle region (50), and two edge regions (60) disposed on both sides of the middle region (50) along the first direction (X); the first separator layer (30) is disposed in the middle region (50), and the second separator layer (40) is disposed in the edge regions (60).
4. The single cell according to claim 3, characterized in that, The number of the second separator layers (40) in the two edge regions (60) is equal.
5. The single cell according to claim 1, characterized in that, The single cell satisfies: 1.23 ≥ T1 / T2 ≥ 1.
07.
6. The single cell according to claim 1, characterized in that, The temperature range of the cut-off temperature of the first separator layer (30) is 150 - 160 °C.
7. The single cell according to claim 1, characterized in that, The temperature range of the cut-off temperature of the second separator layer (40) is 130 - 140 °C.
8. The single cell according to claim 1, characterized in that, The first separator layer (30) and the second separator layer (40) respectively include and are not simultaneously any one of a polyethylene separator layer, a polypropylene separator layer, a polyimide separator layer, a polyester separator layer, a non-woven fabric separator, and a ceramic-coated separator.
9. A battery pack, characterized in that, Comprising a single cell according to any one of claims 1 to 8.
10. An electrical device, characterized in that, Comprising a battery pack according to claim 9.