Battery cell, battery and battery pack

Abstract

The invention provides a battery cell, a battery and a battery pack, the battery cell comprises a positive plate, a negative plate, a diaphragm and a first thermal insulation layer, the diaphragm is laminated between the positive plate and the negative plate, the positive plate, the diaphragm and the negative plate are wound or stacked to form a pole core, and the first thermal insulation layer is arranged between the positive plate and the negative plate. The first heat insulation layer is stacked between the positive plate and the diaphragm or between the negative plate and the diaphragm or between the diaphragm and the diaphragm. In the application, after the battery cell generates heat, the first heat insulation layer can prevent the heat from being transversely conducted to the outer layer, and only a heat conduction channel in the tab direction is reserved. When heated by an external heat source, the thermal runaway time of the inner roll core is prolonged, and the safety is greatly improved.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and more particularly to a battery cell, battery, and battery pack. Background Technology

[0002] Ultra-large capacity battery cells are the industry goal in the battery cell field. However, as the capacity of battery cells increases, the severity of thermal runaway increases significantly. This makes it impossible to effectively guarantee the safety performance of ultra-large capacity battery cells, thus affecting the development of battery cells. Summary of the Invention

[0003] The embodiments of this application provide a battery cell, a battery, and a battery pack. In this embodiment, the battery cell is developing towards ultra-large capacity and high energy density while effectively slowing down the internal heat spread of the battery cell and improving the safety performance of the battery cell.

[0004] In a first aspect, embodiments of this application provide a battery cell, which includes a positive electrode, a negative electrode, a separator, and a first heat insulation layer. The separator layer is stacked between the positive electrode and the negative electrode. The positive electrode, the separator, and the negative electrode are wound or stacked to form an electrode core. The first heat insulation layer is stacked between the positive electrode and the separator, or between the negative electrode and the separator, or between the separators.

[0005] In this embodiment, since the first heat insulation layer is stacked between the positive electrode and the separator, or between the negative electrode and the separator, or between separators, that is, the first heat insulation layer is located inside the electrode core, the electrode core can be divided into two parts by the first heat insulation layer. Through the heat insulation effect of the first heat insulation layer, the heat accumulation between the two parts can be interrupted, thereby effectively reducing the maximum heat accumulation temperature of the two parts, and thus effectively reducing the probability of thermal runaway in the two parts. Especially for cells with high energy density and large capacity, the first heat insulation layer can effectively reduce the risk of internal thermal runaway of the cell, and reduce the probability of thermal runaway of the cell. This can effectively solve the contradictory problem of high capacity of a single cell and increased risk of thermal runaway, thus providing a safe basis for improving the capacity of a single cell.

[0006] Furthermore, since the first insulation layer is located between the two sections, it can reduce or block the heat conduction to the other section when one section experiences a short circuit or is heated by an external heat source (such as another thermally runaway cell). This delays the time it takes for the other section to experience thermal runaway, and consequently delays the time it takes for the cell to fully thermally runaway. This provides more time to control the thermal runaway of the cell and avoids affecting more cells. It is understood that controlling the thermal runaway of the cell can be achieved by increasing the flow rate of the heating or cooling medium, or by spraying fire-fighting media, etc.

[0007] Furthermore, due to the heat-insulating effect of the first insulation layer, heat accumulation can be effectively reduced, thereby lowering the maximum temperature of a single cell within a certain timeframe after thermal runaway occurs. This delays the temperature rise when thermal runaway occurs in a single cell, thus reducing the impact on other cells and preventing or delaying the occurrence of thermal runaway in other cells.

[0008] In some embodiments, the battery cell includes a first portion formed by winding or stacking a positive electrode, a separator, and a negative electrode, and a second portion formed by winding or stacking the same materials. The first and second portions constitute the battery core and are located on opposite sides of two pairs of first thermal insulation layers. In this embodiment, the first thermal insulation layer effectively reduces the probability of thermal runaway in the first and second portions. It also delays the time for complete thermal runaway of the battery cell, providing more time to control thermal runaway and preventing further thermal runaway in other battery cells.

[0009] In some embodiments, the battery cell has a square structure, and at least a portion of the first heat insulation layer is stacked with the positive electrode, separator, and negative electrode in the thickness direction of the battery cell. In this embodiment, since the thermal conductivity of the battery cell is relatively low in its thickness direction, the heat accumulation problem in its thickness direction is also relatively more serious. As a result, the temperature of the middle part in the thickness direction is usually the highest due to the heat accumulation effect. In this embodiment, since at least a portion of the first heat insulation layer is stacked with the positive electrode, separator, and negative electrode in the thickness direction of the battery cell, the first part and the second part are located on opposite sides of the first heat insulation layer in the thickness direction of the battery cell. This effectively blocks the heat conduction between the first part and the second part, preventing the heat from the first part and the heat from the second part from accumulating together due to the heat accumulation effect. This effectively reduces the heat accumulation of the battery cell and lowers the maximum temperature of the battery cell.

[0010] In some embodiments, the projected area of ​​the first thermal insulation layer in the thickness direction of the battery cell is not less than 2 / 3 of the projected area of ​​the electrode core. In this embodiment, since the areas on opposite sides in the thickness direction of the battery cell are relatively larger, and the projection of the first thermal insulation layer in the thickness direction of the battery cell is not less than 2 / 3 of the projected area of ​​the electrode core, it can be ensured that the isolation area of ​​the first thermal insulation layer is not less than 2 / 3 of the projected area of ​​the electrode core. Within this range, the problem of easy heat accumulation in individual battery cells can be effectively solved, and the maximum temperature of individual battery cells during operation or thermal runaway can be effectively reduced.

[0011] In some embodiments, the battery cell further includes a positive tab and a negative tab. The positive tab and the core are arranged in the height direction of the battery cell, and the positive electrode plate is connected to the positive tab. The negative tab and the core are arranged in the height direction of the battery cell, and the negative electrode plate is connected to the negative tab. In the height direction of the battery cell, the end of the first heat insulation layer near the positive and negative tabs protrudes from the core. In this embodiment, because the end of the first heat insulation layer facing the positive and negative tabs protrudes from the end of the core in the height direction of the battery cell, the heat generated by the core can be blocked as much as possible in the thickness direction of the battery cell, and the heat generated by the core can be conducted as much as possible along the height direction of the battery cell. The positive and negative tabs of the battery cell are located in the height direction of the battery cell and are located on the side of the core facing the top cover. Therefore, the heat generated by the core can be transferred to the aluminum busbar on the top cover through the positive and negative tabs as much as possible, thereby effectively improving the heat dissipation effect of the battery cell in the height direction. The improved heat dissipation effect in the height direction of the battery cell can also reduce the heat accumulation in the core.

[0012] In some embodiments, the first thermal insulation layer is used for thermal insulation and to restrict the passage of metal cations from the battery cell. In this embodiment, since the first thermal insulation layer is used to restrict the passage of metal cations from the battery cell, that is, the porosity of the first thermal insulation layer is low, which is not conducive to the passage of metal cations. Thus, the low porosity of the first thermal insulation layer achieves just the right thermal insulation effect, thereby improving the thermal runaway delay capability of the first thermal insulation layer.

[0013] In some embodiments, the electrode core is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet. The first heat insulation layer is wound at least 360 degrees along the winding direction. Specifically, the first heat insulation layer surrounds the outside of the first portion, and the second portion surrounds the outside of the first portion. In this embodiment, since the first heat insulation layer surrounds the first portion at least 360 degrees, it wraps around the first portion at least once, thus essentially completely isolating the inner first portion and the outer second portion. This minimizes heat conduction between the first and second portions, improving the heat insulation effect and thermal runaway prevention capability of the first heat insulation layer.

[0014] In some embodiments, the battery cell includes two sets of positive electrode sheets, separators, and negative electrode sheets. One set of positive electrode sheets, separators, and negative electrode sheets is wound to form a first part, and the other set is wound to form a second part. The start and end ends of the winding direction of a first heat insulation layer are connected to form a closed loop structure, and the first heat insulation layer is located between the first and second parts. In this embodiment, the connection of the start and end ends makes the first heat insulation layer form a closed loop structure. That is, the first part and the second part are not formed by winding the same set of positive electrode sheets, separators, and negative electrode sheets. The heat conduction between the first part and the second part is essentially completely blocked by the first heat insulation layer, thereby greatly reducing the heat transfer efficiency between the first part and the second part, delaying the thermal runaway time, and mitigating the severity of the final thermal runaway. In addition, since the first part and the second part are not formed by winding the same set of positive electrode sheets, separators, and negative electrode sheets, the winding process of the first part and the first heat insulation layer can be separated from the winding process of the second part, thereby improving process flexibility and manufacturing efficiency.

[0015] In some embodiments, the thickness of the first portion in the thickness direction of the cell is 1-2 times the thickness of the second portion. In this embodiment, the electrode core is divided into two parts by a first thermal insulation layer to reduce the risk of thermal runaway in both parts, thereby reducing the risk of thermal runaway in the cell.

[0016] In some embodiments, the first heat insulation layer is wound to form an annular structure with a notch. A portion of the positive electrode, separator, and negative electrode are located inside the annular structure formed by the first heat insulation layer, while another portion of the positive electrode, separator, and negative electrode protrudes through the notch and surrounds the outside of the first heat insulation layer. In this embodiment, the electrode core can be formed by winding the same set of positive electrode, separator, and negative electrode, ensuring that the electrolyte flows and interacts between the inner and outer sides of the first heat insulation layer through the notch, thereby improving the uniformity of the electrolyte at various positions within the electrode core.

[0017] In some embodiments, the electrode core is formed by stacking multiple positive electrode sheets, separators, and negative electrode sheets, with the stacking direction of the multiple positive electrode sheets, separators, and negative electrode sheets being the thickness direction of the battery cell. The first heat insulation layer is also stacked with the multiple positive electrode sheets, separators, or negative electrode sheets in the thickness direction of the battery cell. In this embodiment, since the stacking direction of the multiple positive electrode sheets, separators, and negative electrode sheets and the first heat insulation layer is the thickness direction of the battery cell, not only can the first heat insulation layer achieve a heat insulation effect, but the process is also simple and easy to manufacture.

[0018] In some embodiments, the first and second portions of the cell have the same thickness along the thickness direction. That is, the first thermal insulation layer is located at the 1 / 2 mark of the electrode core along the thickness direction. In this embodiment, the cell is divided into two portions by the first thermal insulation layer to reduce the risk of thermal runaway in both portions, thereby reducing the risk of thermal runaway in the entire cell.

[0019] In some embodiments, the battery cell further includes a second heat insulation layer, which surrounds the outer side of the electrode core. A positive electrode sheet, a separator, or a negative electrode sheet is stacked between the second heat insulation layer and the first heat insulation layer. In this embodiment, the second heat insulation layer provides heat insulation for two adjacent battery cells to reduce the maximum temperature of the battery as a whole during charging and discharging or during thermal runaway.

[0020] In some embodiments, the thermal conductivity of the first insulation layer is less than or equal to 0.3 W / m. · k, the first thermal insulation layer has a temperature tolerance greater than 200℃. In this embodiment, when the temperature tolerance of the first thermal insulation layer is greater than 200℃, that is, below 200℃, the first thermal insulation layer can guarantee its thermal insulation performance. By reasonably setting the first thermal insulation layer, the temperature after failure can be effectively controlled, the heat transfer efficiency between the first and second parts can be reduced, the thermal runaway area of ​​the battery cell can be reduced, the severity of the final thermal runaway can be mitigated, and the thermal runaway time can be delayed.

[0021] In some embodiments, the first thermal insulation layer includes a porous vacuum silicon thermal insulation layer, mica paper, fiberglass cloth, or polytetrafluoroethylene layer. In this embodiment, since the porous vacuum silicon thermal insulation layer, mica paper, fiberglass cloth, or polytetrafluoroethylene layer all have strong thermal insulation capabilities, they can effectively insulate the heat and effectively reduce the risk of thermal runaway of the battery cell after separating the electrode core.

[0022] In some embodiments, the thickness of the first thermal insulation layer is 0.05mm-1mm, and the thickness of the separator is 9μm-16μm. In this embodiment, within this range, the thermal insulation effect and stability of the first thermal insulation layer can be guaranteed, effectively reducing the maximum temperature of the battery cell. Consequently, the separator does not need to bear a large amount of thermal insulation, thus effectively reducing the separator thickness and improving the overall energy density of the battery cell.

[0023] Secondly, embodiments of this application provide a battery, including a casing and a cell located within the casing as described in any of the first aspects.

[0024] Thirdly, embodiments of this application provide a battery pack, which includes a housing and a plurality of batteries located inside the housing. The batteries include a plurality of cells as described in any of the first aspects, and the plurality of batteries are arranged in the cavity of the housing.

[0025] Fourthly, embodiments of this application provide an energy storage device, including a battery cell as described in any of the first aspects.

[0026] Fifthly, embodiments of this application provide a vehicle including a battery cell as described in any of the first aspects.

[0027] Sixthly, embodiments of this application provide a method for manufacturing a wound battery cell, comprising:

[0028] The first part is formed by winding the positive electrode, the separator, and the negative electrode.

[0029] The first insulation layer surrounds the outside of the first part;

[0030] The positive electrode, separator, and negative electrode are wound around the outside of the first heat insulation layer to form a second part.

[0031] Seventhly, embodiments of this application provide a method for manufacturing stacked battery cells, comprising:

[0032] Multiple positive electrode plates, separators, and negative electrode plates are stacked to form the first part;

[0033] A first heat insulation layer is stacked on top of the first part;

[0034] Multiple positive electrode plates, separators, and negative electrode plates are stacked on the first heat insulation layer to form the second part. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0036] Figure 1 This is a schematic diagram of the structure of a battery pack provided in an embodiment of this application;

[0037] Figure 2 This is a schematic diagram of the structure of a battery provided in an embodiment of this application;

[0038] Figure 3 A schematic diagram of another battery structure provided in this application;

[0039] Figure 4 This is a schematic diagram of the structure of a wound battery cell provided in an embodiment of this application;

[0040] Figure 5 This is a schematic diagram of a stacked battery cell structure provided in an embodiment of this application;

[0041] Figure 6 This is a schematic diagram showing the stacking direction between the electrode layer structure and the first heat insulation layer at a certain location of the battery cell;

[0042] Figure 7 for Figure 6 A schematic diagram of the electrode layer structure in the middle;

[0043] Figure 8A This is a side view of a battery cell without a first heat insulation layer during testing.

[0044] Figure 8B This is a side view of an experimental battery cell with a first heat insulation layer.

[0045] Figure 9 A schematic diagram of the structure of a wound pole core and a first heat insulation layer in accordance with an embodiment of this application;

[0046] Figure 10 for Figure 9 A sectional view;

[0047] Figure 11 A schematic diagram of another structure for the combination of a wound pole core and a first heat insulation layer provided in an embodiment of this application;

[0048] Figure 12 for Figure 11 A sectional view;

[0049] Figure 13 A schematic diagram of another structure for the combination of a wound pole core and a first heat insulation layer provided in an embodiment of this application;

[0050] Figure 14 for Figure 13 A sectional view;

[0051] Figure 15 A schematic diagram of a stacked electrode core and a first heat insulation layer provided in an embodiment of this application;

[0052] Figure 16 This is a schematic diagram of the structure of another battery cell provided in an embodiment of this application;

[0053] Figure 17 A manufacturing process diagram of a wound-structured battery cell provided in an embodiment of this application;

[0054] Figure 18 This is a process diagram illustrating the fabrication of a stacked battery cell provided in an embodiment of this application.

[0055] Figure label:

[0056] X: Length direction of the battery cell; Y: Thickness direction of the battery cell; Z: Height direction of the battery cell; L: Stacking direction;

[0057] 1. Battery pack; 2. Housing; 3. Battery; 4. Shell; 5. Outer shell; 6. Top cover; 7a. Positive terminal; 7b. Negative terminal; 8. Battery cell;

[0058] 10. Electrode core; 101. First part; 102. Second part; 11. Electrode layer structure; 111. Positive electrode; 112. Negative electrode; 113. Separator;

[0059] 20. First insulation layer; 21. Starting end; 22. Ending end; 23. Notch;

[0060] 31. Positive electrode ear; 32. Negative electrode ear;

[0061] 40. Second insulation layer. Detailed Implementation

[0062] The following section will first explain some of the terms used in the embodiments of this application.

[0063] The terms "first," "second," "third," "fourth," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0064] In this specification, the terms "vertical" and "parallel" are explained.

[0065] Perpendicularity: The perpendicularity defined in this application is not limited to an absolute perpendicular intersection (with an included angle of 90 degrees). It is permissible for non-absolute perpendicular intersections caused by factors such as assembly tolerances, design tolerances, and structural flatness. It is permissible for errors within a small angular range, such as an assembly error range of 80 to 100 degrees, which can all be understood as a perpendicular relationship.

[0066] Parallelism: The parallelism defined in this application is not limited to absolute parallelism. This definition of parallelism can be understood as basic parallelism, allowing for situations where the parallelism is not absolute due to factors such as assembly tolerances, design tolerances, and structural flatness. These situations may lead to the sliding mating part and the first door panel not being absolutely parallel, but this application also defines such situations as parallelism.

[0067] Figure 1 This is a schematic diagram of the structure of a battery pack 1 provided in an embodiment of this application. Figure 1 The battery pack 1 in the embodiment can be applied to energy storage devices, such as photovoltaic energy storage devices, industrial and commercial energy storage cabinets, container energy storage cabinets, and battery cabinets in data centers.

[0068] Reference Figure 1The battery pack 1 includes a housing 2 and multiple batteries 3 arranged within the housing 2. It is understood that the multiple batteries 3 can be arranged in a single row or multiple rows. In this embodiment, even with an ultra-large capacity, the batteries 3 can effectively reduce the probability of thermal runaway and effectively delay the time of thermal runaway, effectively reducing the impact of thermal runaway batteries 3 on non-thermal runaway batteries 3, thus improving the safety of the battery pack 1.

[0069] In some embodiments, the battery 3 is generally rectangular. Of course, in other embodiments, the battery 3 can also be other flat or cylindrical structures, etc.

[0070] It is understandable that multiple batteries 3 can be electrically connected through aluminum busbars to achieve series or parallel connection of multiple batteries 3. Specifically, multiple batteries 3 can be connected in series or parallel by connecting their terminals to aluminum busbars.

[0071] Figure 2 This is a schematic diagram of the structure of a battery 3 provided in an embodiment of this application; Figure 3 A schematic diagram of another battery 3 provided in this application;

[0072] The battery 3 in this application embodiment can be a lithium-ion battery 3, a sodium-ion battery 3, or other types of battery 3. For example, the negative electrode active material can be one or more of graphite, soft carbon, hard carbon, etc. For example, the positive electrode active material can be one or more of lithium iron phosphate, lithium cobalt oxide, lithium nickel cobalt manganese oxide, NaxMO2 (M is a transition metal atom, 0 < X ​​≤ 1), Prussian blue and its homologues, polyanions (phosphates, fluorinated phosphates, pyrophosphates, and sulfates), etc.

[0073] Reference Figure 2 and Figure 3 The battery 3 includes a housing 4 and a cell 8 located inside the housing 4.

[0074] The housing 4 includes an outer shell 5 with an opening at the top and a top cover 6 for sealing the opening of the outer shell 5. After the top cover 6 covers the opening of the outer shell 5, it together with the outer shell 5 forms the inner cavity of the housing 4, and the battery cell 8 is disposed in the inner cavity of the housing 4.

[0075] It is understandable that the number of battery cells 8 inside the cavity of the casing 4 can be one or more.

[0076] The top cover 6 is provided with a positive terminal 7a and a negative terminal 7b. The positive terminal 7a is connected to the positive tab 31 of the battery cell 8, and the negative terminal 7b is connected to the negative tab 32 of the battery cell 8.

[0077] Reference Figure 2 , Figure 2In the embodiment, the battery cell 8 is a wound battery cell 8, that is, the battery cell 8 is formed by winding.

[0078] Reference Figure 3 , Figure 3 In the embodiment, the battery cell 8 is a stacked battery cell 8, that is, the battery cell 8 is formed by stacking.

[0079] Figure 4 This is a schematic diagram of the structure of a wound battery cell 8 provided in an embodiment of this application; Figure 5 This is a schematic diagram of a stacked battery cell 8 provided in an embodiment of this application; Figure 6 A schematic diagram showing the stacking direction L between the electrode layer structure and the first heat insulation layer 20 at a certain location of the battery cell 8; Figure 6 The schematic diagrams in the embodiments can be applied to Figure 4 The wound cell 8 in the embodiment is also applicable to Figure 5 Stacked battery cell 8 in the embodiment.

[0080] Reference Figures 2-5 In some embodiments, the battery cell 8 includes an electrode core 10 and a first heat insulation layer 20. In the height direction Z of the battery cell 8, the positive electrode tab 31 and the negative electrode tab 32 are located on the side of the electrode core 10 facing the top cover 6, so as to be connected to the positive electrode post 7a and the negative electrode post 7b on the top cover 6.

[0081] Reference Figures 4-6 The electrode core 10 includes an electrode layer structure 11, such as... Figure 4 In the embodiment, the electrode core 10 of the battery cell 8 can be a wound structure formed by winding one or more electrode layer structures 11. For example... Figure 5 In the embodiment, the electrode core 10 of the battery cell 8 can be a stacked structure formed by stacking multiple electrode layer structures 11.

[0082] The electrode layer structure 11 and the first heat insulation layer 20 are stacked. It is understood that for the wound electrode core 10, the stacking direction L of the electrode layer structure 11 and the first heat insulation layer 20 at different positions may be different; for example, it may be consistent with the thickness direction Y of the cell 8, or it may be consistent with the length direction X of the cell 8, etc. For the stacked electrode core 10, the stacking direction L of the electrode layer structure 11 and the first heat insulation layer 20 is consistent with the thickness direction Y of the cell 8.

[0083] Figure 7 for Figure 6 A schematic diagram of the electrode layer structure 11 in the diagram.

[0084] Reference Figure 7In some embodiments, the electrode layer structure 11 includes a positive electrode 111, a negative electrode 112, and a separator 113 stacked between the positive electrode 111 and the negative electrode 112. That is, the positive electrode 111, the separator 113, and the negative electrode 112 are wound or stacked to form the electrode core 10.

[0085] For example, in some embodiments, the electrode layer structure 11 includes a positive electrode 111, a negative electrode 112, and two separators 113. A separator 113 is provided between the positive electrode 111 and the negative electrode 112. The separator 113 is used to prevent the positive electrode 111 and the negative electrode 112 from short-circuiting. At the same time, the separator 113 also allows the metal cations of the battery cell 8 to pass through the separator 113, so that the battery cell 8 can be charged and discharged normally. For example, for a lithium-ion battery cell 8, lithium ions can pass through the separator 113, and for a sodium-ion battery cell 8, sodium ions can pass through the separator 113.

[0086] In some embodiments, another separator 113 is located on the side of the positive electrode 111 facing away from the negative electrode 112, or the other separator 113 is located on the side of the negative electrode 112 facing away from the positive electrode 111, that is, the positive electrode 111 or the negative electrode 112 is located between the two separators 113. The other separator 113 is used to prevent the positive electrode 111 or the negative electrode 112 from short-circuiting during winding or stacking.

[0087] Reference Figures 4-7In some embodiments, the first heat insulation layer 20 is stacked between the positive electrode 111 and the separator 113, between the negative electrode 112 and the separator 113, or between two separators. Since the first heat insulation layer 20 is stacked between the positive electrode 111 and the separator 113, between the negative electrode 112 and the separator 113, or between two separators, that is, the first heat insulation layer 20 is disposed inside the electrode core 10, the electrode core 10 can be divided into two parts by the first heat insulation layer 20. Through the heat insulation effect of the first heat insulation layer 20, the heat accumulation between the two parts can be interrupted, thereby effectively reducing the maximum heat accumulation temperature of the two parts, and thus effectively reducing the probability of thermal runaway in the two parts. Especially for battery cells 8 with high energy density and large capacity, the first thermal insulation layer 20 can effectively reduce the risk of internal thermal runaway and the probability of thermal runaway in battery cells 8. This effectively solves the contradictory problem of high capacity and increased risk of thermal runaway in individual battery cells, providing a safe foundation for improving the capacity of individual battery cells. Furthermore, since the first thermal insulation layer 20 is located between the two parts, it can reduce or block the heat transfer to the other part when one part is short-circuited or heated by an external heat source (such as other thermally runaway battery cells), delaying the time for thermal runaway in the other part. This, in turn, delays the time for complete thermal runaway of battery cell 8, providing more time to control the thermal runaway of battery cell 8 and preventing the thermal runaway of more battery cells 8 from being affected. It is understood that the method of controlling the thermal runaway of battery cell 8 can be by increasing the flow rate of the hot and cold medium, or by spraying fire-fighting media, etc.

[0088] Reference Figures 4-7In some embodiments, the electrode core 10 includes a first portion 101 formed by winding or stacking a positive electrode sheet 111, a separator 113, and a negative electrode sheet 112, and a second portion 102 formed by winding or stacking the same materials. The first portion 101 and the second portion 102 together constitute the electrode core 10. The two portions of the electrode core 10 separated by a first heat insulation layer 20 are the first portion 101 and the second portion 102. In the stacking direction L of the first heat insulation layer 20 and the electrode layer structure 11, the first portion 101 and the second portion 102 are located on opposite sides of the first heat insulation layer 20. That is, the first portion 101, the first heat insulation layer 20, and the second portion 102 are arranged in the stacking direction L of the first heat insulation layer 20 and the electrode layer structure 11. It is understood that both the first portion 101 and the second portion 102 are formed by the electrode layer structure 11. For example, the first part 101 can be formed by winding or stacking electrode layer structures 11, such as by winding one electrode layer structure 11 or a portion or multiple electrode layer structures 11, or by stacking multiple electrode layer structures 11. Similarly, the second part 102 can be formed by winding or stacking electrode layer structures 11, such as by winding one electrode layer structure 11 or a portion or multiple electrode layer structures 11, or by stacking multiple electrode layer structures 11.

[0089] In this embodiment, since the first heat insulation layer 20 is located between the first part 101 and the second part 102, the heat accumulation between the first part 101 and the second part 102 can be blocked through the heat insulation effect of the first heat insulation layer 20. That is, the heat of the first part 101 can be blocked from being conducted to the second part 102, and the heat of the second part 102 can be blocked from being conducted to the first part 101. This can effectively reduce the maximum heat accumulation temperature of the first part 101 and the second part 102, thereby effectively reducing the risk of thermal runaway in the first part 101 and the second part 102. Especially for the battery cell 8 with high energy density and ultra-large capacity, the first heat insulation layer 20 can effectively reduce the risk of thermal runaway inside the battery cell 8 and reduce the probability of thermal runaway in the battery cell 8. This can effectively solve the contradictory problem of high capacity of battery cell 8 and increased risk of thermal runaway, and serve as a safe basis for improving the capacity of battery cell 8.

[0090] Furthermore, since the first thermal insulation layer 20 is located between the first part 101 and the second part 102, it can reduce or block the heat conduction to the other part when one part experiences a short circuit or is heated by an external heat source (such as other thermally runaway cells 8), thus delaying the time when the other part experiences thermal runaway. This, in turn, delays the time when the cell 8 completely experiences thermal runaway, providing more time to control the thermal runaway of the cell 8 and preventing it from affecting more cells 8. It is understood that controlling the thermal runaway of the cell 8 can be achieved by increasing the flow rate of the hot and cold medium, or by spraying fire-fighting media, etc. Under the premise that the cell 8 only experiences localized thermal failure and does not experience severe thermal runaway, the first thermal insulation layer 20 can also effectively reduce the maximum heat accumulation temperature, thus reducing the impact on other normal cells 8.

[0091] Furthermore, due to the heat-insulating effect of the first insulation layer 20, heat accumulation can be effectively reduced, thereby lowering the maximum temperature of a single cell 8 within a certain period after thermal runaway, which delays the temperature rise when thermal runaway occurs in cell 8. This reduces the impact on other cells 8, avoiding or delaying the occurrence of thermal runaway in other cells 8.

[0092] For example, attached Figure 8A For battery 3 without the first heat insulation layer 20, attached Figure 8B For the battery 3 equipped with a first heat insulation layer 20, via an attached Figure 8A The experimental results shown in the attached figure indicate that, at a thermal runaway time of 3300 s, the highest temperature of battery 3 was 517.787℃. (The remaining text appears to be incomplete and requires further context.) Figure 8B As shown in the attached experimental results, when the thermal runaway time is 3300s, the highest temperature of battery 3 is 284.692℃. In other words, by setting the first heat insulation layer 20, the temperature rise of cell 8 during thermal runaway can be effectively delayed, thus providing more time to control the thermal runaway of cell 8.

[0093] It is understandable that the core 10 may include not only the first part 101 and the second part 102, but also more parts, such as the third part, the fourth part, etc., which are arranged in the same direction as the first part 101 and the second part 102.

[0094] In some embodiments, the thermal conductivity of the first insulation layer 20 is less than or equal to 0.3 W / m. · k. For example, the thermal conductivity of the first insulation layer 20 can be 0.1 W / m. · k, 0.15W / m · k, 0.2W / m · k, 0.25W / m ·k, etc. When the thermal conductivity of the first insulation layer 20 is less than 0.3 W / m · When k is used, the heat conduction between the first part 101 and the second part 102 can be effectively reduced or blocked, thereby achieving a heat insulation effect.

[0095] In order to extend the stable thermal insulation effect of the first thermal insulation layer 20 in more scenarios, in some embodiments, the first thermal insulation layer 20 not only has the function of thermal insulation, but can also withstand high temperatures. For example, in the state of thermal runaway of the battery cell 8, the first thermal insulation layer 20 can ensure its normal performance, and thus can still play the role of thermal insulation when the battery cell 8 is thermally runaway, thereby effectively reducing the overall temperature of the battery cell 8 when it is thermally runaway and delaying the spread of thermal runaway of the battery cell 8.

[0096] In some embodiments, the first heat insulation layer 20 has a temperature resistance greater than 200°C. Generally speaking, the melting point of the electrode layer structure 11 that makes up the electrode core 10 is usually below 200°C, so that when the temperature resistance of the first heat insulation layer 20 is greater than 200°C, that is, below 200°C, the first heat insulation layer 20 can ensure its heat insulation performance.

[0097] In some embodiments, after the first heat insulation layer 20 isolates the first part 101 and the second part 102, the temperature after failure can be effectively controlled by properly setting the first heat insulation layer 20, reducing the heat transfer efficiency between the first part 101 and the second part 102, reducing the thermal runaway area of ​​the battery cell 8, mitigating the degree of harm of the final thermal runaway, and delaying the thermal runaway time.

[0098] In some embodiments, the first thermal insulation layer 20 has a temperature tolerance greater than 300°C, such as 280°C or 270°C. Under the thermal insulation effect of the first thermal insulation layer 20, when the battery cell 8 experiences thermal runaway, the temperatures at which the first part 101 and the second part 102 experience thermal runaway are less than 300°C. Therefore, even when the first part 101 and the second part 102 experience thermal runaway, the thermal insulation performance of the first thermal insulation layer 20 can still be guaranteed. For example, see attached... Figure 8B The experimental results are shown in the attached figure. Due to the presence of the first heat insulation layer 20, the highest temperature of the battery cell 8 during a certain period of thermal runaway is 284.5℃. Since the first heat insulation layer 20 can withstand temperatures greater than 300℃, its heat insulation performance can still be guaranteed at this time.

[0099] It is understood that in some other embodiments, the temperature that the first insulation layer 20 can withstand may be 400°C, 500°C, 600°C, 700°C, 800°C, 900°C or higher.

[0100] In order to improve the heat insulation effect and heat insulation stability of the first heat insulation layer 20, in some embodiments, the first heat insulation layer 20 is used to restrict the passage of metal cations of the battery cell 8, that is, the metal cations cannot pass through the first heat insulation layer 20, that is, the porosity of the first heat insulation layer 20 is low, which is not conducive to the passage of metal cations. Thus, the low porosity of the first heat insulation layer 20 achieves just the right heat insulation effect, thereby improving the thermal runaway resistance of the first heat insulation layer 20.

[0101] In some embodiments, the first heat insulation layer 20 is a porous vacuum silicon heat insulation layer. Of course, in other embodiments, the first heat insulation layer 20 can also be a heat insulation layer made of materials such as mica paper, fiberglass cloth, or polytetrafluoroethylene. It can also be a heat insulation layer made of other materials that meet the requirements of high temperature resistance and low thermal conductivity.

[0102] Reference Figure 7 In some embodiments, the first heat insulation layer 20 is in contact with the separator 113 of the electrode layer structure 11 in the stacking direction L of the first heat insulation layer 20 and the electrode layer structure 11. It is understood that the electrode layer structure 11 may also include three separators 113. In this embodiment, since the positive electrode 111 and negative electrode 112 of the electrode layer structure 11 on both sides of the first heat insulation layer 20 are not only provided with the first heat insulation layer 20, but also with the separator 113, the probability of short circuit between the positive electrode 111 and negative electrode 112 of the electrode layer structure 11 on both sides of the first heat insulation layer 20 can be reduced. Moreover, with the mutual reinforcement of the first heat insulation layer 20 and the separator 113, the heat conduction barrier effect on the electrode layer structure 11 on both sides of the first heat insulation layer 20 can be improved.

[0103] Reference Figure 7 In some embodiments, the thickness of the first heat insulation layer 20 is 0.05mm-1mm, and the thickness of the separator 113 is 9μm-16μm. Within this range, the heat insulation effect and stability of the first heat insulation layer 20 can be guaranteed, effectively reducing the maximum temperature of the battery cell 8. Consequently, the separator 113 does not need to bear a large heat insulation burden, thus effectively reducing the thickness of the separator 113 and improving the overall energy density of the battery cell 8.

[0104] In some embodiments, the battery cell 8 is generally square in shape. For example, refer to... Figure 4 For the wound-structure battery cell 8, both ends of the cell 8 along its length X are approximately arc-shaped. For example, refer to... Figure 5 For the stacked cell 8, the overall structure is closer to a regular square structure.

[0105] To effectively reduce heat accumulation in the 8 individual cells and lower their maximum temperature, refer to... Figure 4 and Figure 5In some embodiments, at least a portion of the first heat insulation layer 20 is stacked with the electrode layer structure 11 in the thickness direction Y of the cell 8. Since the thermal conductivity of the cell 8 is relatively low in its thickness direction, the heat accumulation problem in that direction is also relatively more severe. Therefore, under the effect of heat accumulation, the temperature in the middle portion of the thickness direction is usually the highest. In this embodiment, since at least a portion of the first heat insulation layer 20 is stacked with the electrode layer structure 11 in the thickness direction Y of the cell 8, the first portion 101 and the second portion 102 are located on opposite sides of the first heat insulation layer 20 in the thickness direction Y of the cell 8. This effectively blocks heat conduction between the first portion 101 and the second portion 102, preventing the heat from accumulating together due to the heat accumulation effect. This effectively reduces the heat accumulation in the individual cell 8 and lowers the maximum temperature of the individual cell 8.

[0106] Reference Figure 4 and Figure 5 For example, in some embodiments, in the thickness direction Y of the cell 8, the projection of the portion where the first heat insulation layer 20 and the electrode layer structure 11 overlap is not less than 2 / 3 of the projected area of ​​the electrode core 10. In this embodiment, since the areas on opposite sides of the cell 8 in the thickness direction are relatively larger, and the projection of the portion where the first heat insulation layer 20 and the electrode layer structure 11 overlap is not less than 2 / 3 of the projected area of ​​the electrode core 10, it can be ensured that the isolation area of ​​the first heat insulation layer 20 is not less than 2 / 3 of the projected area of ​​the electrode core 10. Within this range, the problem of easy heat accumulation in a single cell of the cell 8 can be effectively solved, and the maximum temperature of a single cell of the cell 8 during operation or thermal runaway can be effectively reduced.

[0107] It is understood that in some other embodiments, the projection of the portion of the first heat insulation layer 20 and the electrode layer structure 11 overlapping in the thickness direction Y of the cell 8 is not less than 3 / 4, 4 / 5, 5 / 6, etc. of the projected area of ​​the electrode core 10.

[0108] Reference Figure 4 and Figure 5 and Figure 7In some embodiments, the positive tab 31 is connected to the positive electrode plate 111, and the negative tab 32 is connected to the negative electrode plate 112. In the height direction Z of the cell 8, the end of the first heat insulation layer 20 near the positive tab 31 and the negative tab 32 protrudes from the electrode layer structure 11, that is, it protrudes from the end of the electrode core 10 in the height direction Z of the cell 8 where the positive tab 31 and the negative tab 32 are connected. In this embodiment, because the first heat insulation layer 20 protrudes from the electrode layer structure 11 at one end near the positive tab 31 and negative tab 32 in the height direction Z of the cell 8, the heat generated by the electrode core 10 can be blocked as much as possible in the thickness direction Y of the cell 8. Instead, the heat generated by the electrode core 10 is conducted as much as possible along the height direction Z of the cell 8. The positive tab 31 and negative tab 32 of the cell 8 are located in the height direction Z of the cell 8 and are on the side of the electrode core 10 facing the top cover 6. Thus, the heat generated by the electrode core 10 can be transferred as much as possible through the positive tab 31 and negative tab 32 to the aluminum busbar on the top cover 6, thereby effectively improving the heat dissipation effect of the cell 8. The improved heat dissipation effect in the height direction Z of the cell 8 can also reduce the heat accumulation of the electrode core 10.

[0109] It can be understood that, in some other embodiments, the two ends of the first heat insulation layer 20 may be flush with the two ends of the electrode core 10 in the height direction Z of the cell 8, or even located inside the two ends of the electrode core 10.

[0110] Figure 9 A schematic diagram of the structure of a wound pole core 10 and a first heat insulation layer 20 in accordance with an embodiment of this application; Figure 10 for Figure 9 A sectional view.

[0111] Reference Figure 9 and Figure 10 In some embodiments, the electrode core 10 is formed by winding an electrode layer structure 11, with a first heat insulation layer 20 surrounding the outside of the first portion 101, a second portion 102 surrounding the outside of the first portion 101, and the first heat insulation layer 20 located between the first portion 101 and the second portion 102. It is understood that the first heat insulation layer 20 surrounding the outside of the first portion 101 includes not only a complete circle of the first heat insulation layer 20 around the first portion 101, but also less than one circle.

[0112] Reference Figure 9 and Figure 10In some embodiments of this invention, the first heat insulation layer 20 surrounds the first portion 101 at least 360 degrees. In this embodiment, since the first heat insulation layer 20 surrounds the first portion 101 at least 360 degrees, it effectively surrounds the first portion 101 at least once, thereby essentially isolating the inner first portion 101 and the outer second portion 102 through the first heat insulation layer 20. This reduces heat conduction between the first portion 101 and the second portion 102 as much as possible, improving the heat insulation effect and thermal runaway prevention capability of the first heat insulation layer 20.

[0113] It is understood that the electrode core 10 in this embodiment can be formed by winding a single electrode layer structure 11. That is, the first part 101 and the second part 102 are formed by winding the same electrode layer structure 11, meaning that the first part 101 and the second part 102 are connected and not completely separated by the first heat insulation layer 20. Of course, the electrode core 10 in this embodiment can also be formed by winding multiple electrode layer structures 11. For example, the first part 101 and the second part 102 can be formed by winding two different electrode layer structures 11.

[0114] Reference Figure 9 and Figure 10 The battery cell 8 includes two sets of positive electrode plates 111, separators 113 and negative electrode plates 112. One set of positive electrode plates 111, separators 113 and negative electrode plates 112 are wound to form a first part 101, and the other set of positive electrode plates 111, separators 113 and negative electrode plates 112 are wound to form a second part 102. The starting end 21 and the ending end 22 of the first heat insulation layer 20 in the winding direction are connected to form a closed ring structure. The first heat insulation layer 20 is located between the first part 101 and the second part 102. In this embodiment, the first part 101 and the second part 102 are not formed by winding the same electrode layer structure 11. For example, the first part 101 can be formed by winding one electrode layer structure 11, and the second part 102 can be formed by winding another electrode layer structure 11. The first heat insulation layer 20 completely isolates the first part 101 and the second part 102, so the heat conduction between the first part 101 and the second part 102 is basically completely blocked by the first heat insulation layer 20, which can greatly reduce the probability of thermal runaway of the battery cell 8 due to heat accumulation. In addition, since the first part 101 and the second part 102 are not formed by winding the same electrode layer structure 11, the winding process of the first part 101 and the first heat insulation layer 20 can be carried out separately from the winding process of the second part 102, so as to improve process flexibility and improve manufacturing efficiency.

[0115] It is understood that the starting end 21 and the ending end 22 of the first heat insulation layer 20 refer to the starting end 21 and the ending end 22 of the winding direction of the first heat insulation layer 20, and the winding direction of the first heat insulation layer 20 is the same as the winding direction of the electrode layer structure 11.

[0116] In some embodiments, in the thickness direction of the cell 8, the thickness L1 of the first portion 101 is 1-2 times the thickness L2 of the second portion 102. The electrode core 10 is divided into two portions by the first thermal insulation layer 20 to reduce the risk of thermal runaway of the two portions, thereby reducing the risk of thermal runaway of the cell 8.

[0117] Figure 11 A schematic diagram of another structure for the cooperation of a wound pole core 10 and a first heat insulation layer 20 provided in an embodiment of this application; Figure 12 for Figure 11 A sectional view. Figure 11 and Figure 12 Compared to Figure 9 and Figure 10 The main difference in the embodiment is that the starting end 21 and the ending end 22 of the first insulation layer 20 are not connected to form a closed ring structure.

[0118] Reference Figure 11 and Figure 12 In some embodiments, the first heat insulation layer 20 is wound to form an annular structure with a notch 23, that is, the starting end 21 and the ending end 22 of the first heat insulation layer 20 are not connected in the winding direction, thus forming the notch 23. Parts of the positive electrode 111, the separator 113, and the negative electrode 112 are located inside the annular structure formed by the first heat insulation layer 20, and other parts of the positive electrode 111, the separator 113, and the negative electrode 112 protrude from the notch 23 and surround the outside of the first heat insulation layer 20. In this embodiment, the electrode core 10 can be formed by winding the same set of positive electrode 111, separator 113, and negative electrode 112, which can ensure that the electrolyte between the inner and outer sides of the first heat insulation layer 20 flows and interacts through the notch 23, thereby improving the uniformity of the electrolyte at various positions of the electrode core 10.

[0119] Figure 13 A schematic diagram of the structure of another type of wound pole core 10 and first heat insulation layer 20 provided in the embodiments of this application; Figure 14 for Figure 13 A sectional view. Figure 13 and Figure 14 Compared to Figure 9 and Figure 10 The main difference in the embodiment is that the first insulation layer 20 surrounds the first part 101 less than 360 degrees.

[0120] Reference Figure 13 and Figure 14In some embodiments, the first heat insulation layer 20 is located at the center of the electrode core 10. The first heat insulation layer 20 is approximately perpendicular to the thickness direction Y of the battery cell 8. In the thickness direction Y of the battery cell 8, the thickness of the portions of the electrode core 10 located on both sides of the first heat insulation layer 20 is approximately the same. That is, in this embodiment, the first portion 101 and the second portion 102 are no longer in a surrounding relationship, but are in a basically symmetrical relationship with respect to the first heat insulation layer 20. In this embodiment, when winding the electrode layer structure 11, the first heat insulation layer 20 can be stacked at the starting position of the electrode layer structure 11, and the length of the first heat insulation layer 20 is less than the length of the battery cell 8. Then, the first heat insulation layer 20 is wound around the center of the electrode core 10 by winding. Since the first heat insulation layer 20 is located at the starting position of the electrode layer structure 11, this design eliminates the need to stop the winding process during winding, thus avoiding repeated adjustments to winding-related parameters, simplifying the process steps and ensuring precise winding.

[0121] Figure 15 This is a schematic diagram of a stacked pole core 10 and a first heat insulation layer 20 provided in an embodiment of this application.

[0122] Reference Figure 15 In some embodiments, the electrode core 10 is formed by stacking multiple electrode layer structures 11, with the stacking direction of the electrode layer structures 11 being the thickness direction Y of the battery cell 8. The stacking direction L of the first heat insulation layer 20 and the multiple electrode layer structures 11 is also the thickness direction Y of the battery cell 8. That is, the first part 101 and the second part 102 are arranged in the thickness direction Y of the battery cell 8. In this embodiment, since the stacking direction L of the multiple electrode layer structures 11 and the first heat insulation layer 20 is the thickness direction Y of the battery cell 8, not only can the first part 101 and the second part 102 be well isolated by the first heat insulation layer 20, achieving a heat insulation effect, but the process is also simple and easy to manufacture.

[0123] In some embodiments, the first portion 101 and the second portion 102 have the same thickness in the thickness direction Y of the cell 8.

[0124] It should be noted that there may be more than one first heat insulation layer 20, or even multiple layers, to isolate the ultra-large capacity electrode core 10 multiple times, so as to avoid the excessive temperature caused by heat accumulation in the electrode core 10.

[0125] For example, when the thickness of the ultra-large capacity battery cell 8 is very thick, multiple first heat insulation layers 20 can be used to isolate the electrode core 10 in more than three parts in the thickness direction Y of the battery cell 8. For example, a first heat insulation layer 20 can be provided at 1 / 3 and 2 / 3 of the thickness direction Y of the battery cell 8 respectively.

[0126] Similarly, for the wound cell 8, multiple first heat insulation layers 20 can be used to isolate the large-capacity electrode core 10 multiple times to avoid excessive temperature caused by heat accumulation in the electrode core 10.

[0127] Figure 16 This is a schematic diagram of another type of battery cell 8 provided in an embodiment of this application.

[0128] The battery cell 8 also includes a second heat insulation layer 40 surrounding the outer side of the electrode core 10, and an electrode layer structure 11 (e.g., ...) is provided between the second heat insulation layer 40 and the first heat insulation layer 20 in the stacking direction L. Figure 6 That is, the second heat insulation layer 40 and the first heat insulation layer 20 are spaced apart by the electrode layer structure 11 in the stacking direction L. The second heat insulation layer 40 provides heat insulation for two adjacent cells 8 to reduce the maximum temperature of the battery 3 as a whole during charging and discharging or thermal runaway.

[0129] In some embodiments, the second heat insulation layer 40 surrounds the electrode core 10 at least once to substantially completely surround the electrode core 10, thereby providing heat insulation for adjacent two cells 8 to reduce the maximum temperature of the battery 3 as a whole during charging and discharging or during thermal runaway.

[0130] Figure 17 This is a process diagram of the winding structure of the battery cell 8 provided in the embodiments of this application.

[0131] Reference Figure 17 For the wound-type battery cell 8, this application provides a manufacturing method for manufacturing the wound-type battery cell 8, which includes the following steps:

[0132] S101, the wound electrode layer structure 11 forms the first part 101; it is understood that the first part 101 can be wound into a cylindrical structure or into a roughly square structure, etc.

[0133] S102, The first heat insulation layer 20 surrounds the outside of the first part 101; it is understood that the first heat insulation layer 20 may surround the first part 101 for one or more times, or it may surround the first part 101 for less than one time, such as 180 degrees, 270 degrees, etc.

[0134] S103, the coiled electrode layer structure 11 is wound outside the first heat insulation layer 20 and forms a second part 102; the first part 101 and the second part 102 are combined to form the electrode core 10. It can be understood that the second part 102 and the first part 101 can be formed by the same electrode layer structure 11 or by different electrode layer structures 11.

[0135] S104. A second heat insulation layer 40 is placed around the outside of the pole core 10. It is understood that the second heat insulation layer 40 may surround the pole core 10 once or more, or it may surround the pole core 10 less than once, such as 180 degrees, 270 degrees, etc.

[0136] Through the above steps S101-S104, a wound battery cell 8 can be formed. The battery cell 8 made in this way has a first heat insulation layer 20, which can effectively reduce the maximum temperature of the battery cell 8 during charging and discharging, and reduce the risk of thermal runaway. The battery cell 8 manufactured by the manufacturing method in this embodiment has the same performance as the battery cell 8 mentioned above. Please refer to the above for details, which will not be repeated here.

[0137] After the battery cell 8 is formed through the above steps S101-S104, the battery cell 8 can be grouped together and then installed into the casing 4 to manufacture the battery 3.

[0138] Figure 18 This is a process diagram of the stacked structure of the battery cell 8 provided in the embodiments of this application.

[0139] Reference Figure 18 For the stacked battery cell 8, this application provides a manufacturing method for manufacturing the stacked battery cell 8, which includes the following steps:

[0140] S201, multiple electrode layer structures 11 are stacked to form the first part 101; it can be understood that the direction of the multiple electrode layer structures 11 stacked is the thickness direction Y of the cell 8.

[0141] S202, A first heat insulation layer 20 is stacked on the first part 101; that is, the first heat insulation layer 20 is stacked with the multiple electrode layer structures 11 constituting the first part 101; wherein the stacking direction L of the first heat insulation layer 20 and the first part 101 is the thickness direction Y of the cell 8.

[0142] S203, Multiple electrode layer structures 11 are stacked on the first heat insulation layer 20 to form a second part 102; the first part 101 and the second part 102 are combined to form an electrode core 10; it is understood that the electrode core 10 includes not only the first part 101 and the second part 102, but may also include other parts besides the first part 101 and the second part 102.

[0143] S204. In the stacking direction L of the multiple electrode layer structures 11, a second heat insulation layer 40 is stacked on both sides of the electrode core 10.

[0144] Through the above steps S201-S204, a stacked battery cell 8 can be formed. The battery cell 8 made in this way has a first heat insulation layer 20, which can effectively reduce the maximum temperature of the battery cell 8 during charging and discharging, and reduce the risk of thermal runaway. The battery cell 8 manufactured by the manufacturing method in this embodiment has the same performance as the battery cell 8 mentioned above. Please refer to the above for details, which will not be repeated here.

[0145] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A battery cell, characterized in that, The battery cell includes a positive electrode, a negative electrode, a separator, and a first heat insulation layer. The separator is stacked between the positive electrode and the negative electrode. The positive electrode, the separator, and the negative electrode are wound or stacked to form an electrode core. The first heat insulation layer is stacked between the positive electrode and the separator, or between the negative electrode and the separator, or between the separators.

2. The battery cell according to claim 1, characterized in that, The battery cell includes a first portion formed by winding or stacking the positive electrode, the separator, and the negative electrode, and a second portion formed by winding or stacking the positive electrode, the separator, and the negative electrode. The first portion and the second portion constitute the electrode core and are located on opposite sides of the first heat insulation layer.

3. The battery cell according to claim 1 or 2, characterized in that, The battery cell also includes a positive electrode tab and a negative electrode tab. The positive electrode tab and the electrode core are arranged in the height direction of the battery cell, and the negative electrode tab and the electrode core are arranged in the height direction of the battery cell. The positive electrode sheet is connected to the positive electrode tab, and the negative electrode sheet is connected to the negative electrode tab. In the height direction of the battery cell, the end of the first heat insulation layer near the positive electrode tab and the negative electrode tab protrudes from the electrode core.

4. The battery cell according to any one of claims 1-3, characterized in that, The first heat insulation layer is used to restrict the passage of metal cations from the battery cell.

5. The battery cell according to any one of claims 1-4, characterized in that, The electrode core is formed by winding the positive electrode, the separator, and the negative electrode, with the first heat insulation layer wound at least 360 degrees along the winding direction.

6. The battery cell according to claim 2, characterized in that, The battery cell includes two sets of positive electrode plates, a separator, and a negative electrode plate. One set of positive electrode plates, a separator, and a negative electrode plate are wound to form the first part, and the other set of positive electrode plates, a separator, and a negative electrode plate are wound to form the second part. The starting end and the ending end of the winding direction of the first heat insulation layer are connected to form a closed loop structure. The first heat insulation layer is located between the first part and the second part.

7. The battery cell according to claim 6, characterized in that, In the thickness direction of the battery cell, the thickness of the first portion is 1-2 times the thickness of the second portion.

8. The battery cell according to claim 5, characterized in that, The first heat insulation layer is wound to form an annular structure with a notch. Parts of the positive electrode, the separator, and the negative electrode are located inside the annular structure formed by the first heat insulation layer, and other parts of the positive electrode, the separator, and the negative electrode protrude from the notch and surround the outside of the first heat insulation layer.

9. The battery cell according to any one of claims 1-4, characterized in that, The electrode core is formed by stacking multiple positive electrode plates, the separator, and the negative electrode plates. The stacking direction of the multiple positive electrode plates, the separator, and the negative electrode plates is the thickness direction of the battery core. The stacking direction of the first heat insulation layer with the multiple positive electrode plates, the separator, or the negative electrode plates is the thickness direction of the battery core.

10. The battery cell according to claim 9, characterized in that, In the thickness direction of the battery cell, the first heat insulation layer is located at 1 / 2 of the electrode core.

11. The battery cell according to any one of claims 1-10, characterized in that, The battery cell also includes a second heat insulation layer, which surrounds the outside of the electrode core. The positive electrode, the separator, or the negative electrode is stacked between the second heat insulation layer and the first heat insulation layer.

12. The battery cell according to any one of claims 1-11, characterized in that, The thermal conductivity of the first insulation layer is less than or equal to 0.3 W / m. · k, the temperature resistance of the first insulation layer is greater than 200℃.

13. The battery cell according to any one of claims 1-12, characterized in that, The first heat insulation layer includes a porous vacuum silicon heat insulation layer, mica paper, glass fiber cloth, or polytetrafluoroethylene layer.

14. The battery cell according to any one of claims 1-13, characterized in that, The thickness of the first heat insulation layer is 0.05mm-1mm, and the thickness of the diaphragm is 9μm-16μm.

15. A battery, characterized in that, It includes a housing and a battery cell located within the housing as described in any one of claims 1-14.

16. A battery pack, characterized in that, The battery pack includes a housing and a plurality of batteries located within the housing, the batteries comprising a plurality of cells as described in any one of claims 1-14, the plurality of batteries being arranged in the cavity of the housing.

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