Battery cell, battery, and electric device

Abstract

The application relates to a battery monomer, a battery and a power utilization device. The battery monomer comprises a shell with a containing cavity, an electrode assembly arranged in the containing cavity and a protective film arranged on the outer surface of the shell. The protective film comprises a main body area and an edge area arranged on at least one side of the main body area. The thickness of the protective film in the edge area is smaller than that in the main body area. Thus, the edge lifting problem of the edge area can be improved, the stability of the protective film and the battery monomer is improved, and the service life of the battery monomer is improved.

Description

Technical Field

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

[0002] Rechargeable batteries are becoming increasingly widely used in the market, and the demand for battery performance stability is also rising. To prevent the battery cell casing from being corroded by external environmental factors such as moisture, oxygen, acids, and alkalis, and to extend the battery cell's lifespan and maintain stable performance, a protective film is typically applied to the outer surface of the battery cell casing. However, in practical applications, it has been found that the adhesion stability between the protective film and the casing is poor, thus affecting the battery cell's lifespan. Summary of the Invention

[0003] Therefore, it is necessary to provide a battery cell, battery, and power device to address the problem of poor adhesion stability between the protective film and the battery cell casing.

[0004] A first aspect of this application provides a battery cell, comprising:

[0005] The shell has a receiving cavity;

[0006] Electrode assembly, disposed within the receiving cavity; and

[0007] A protective film is disposed on the outer surface of the housing; the protective film includes a main body area and an edge area located on at least one side of the main body area, and the thickness of the protective film in the edge area is less than the thickness in the main body area.

[0008] The aforementioned battery cell, through structural optimization of the protective film, has a larger thickness in the main body area and a thinner thickness in the edge area. The thinner edge area is less prone to lifting, thus improving the edge lifting problem, enhancing the stability of the adhesion between the protective film and the battery cell, enabling the protective film to play a stable insulating role, and extending the service life of the battery cell.

[0009] In some embodiments, the thickness of the protective film in the edge region is 0.05 mm to 0.3 mm; and / or,

[0010] The thickness of the protective film in the main body area is 0.1mm to 2.0mm, and can be selected as 0.2mm to 1.0mm.

[0011] By controlling the thickness of the protective film in the edge area within the above range, the edge area can have better anti-lifting performance.

[0012] By controlling the thickness of the protective film in the main body area within the above-mentioned range, the main body area can have better insulation and protection.

[0013] In some embodiments, the ratio of the thickness of the protective film in the edge region to the thickness in the main body region is (0.05~0.8):1, optionally (0.05~0.5):1. Controlling the thickness ratio allows for a better balance between good protection in the main body region and good anti-lifting performance in the edge region.

[0014] In some embodiments, the size of the edge region is ≥4mm, optionally 4mm~40mm, in the direction from one end of the edge region adjacent to the main body region to the other end. Controlling the size W of the edge region 102 to ≥4mm can further improve the edge region lifting problem, improve the adhesion stability between the protective film and the shell, and extend the service life of the battery cell.

[0015] In some embodiments, the main body region of the protective film includes a first insulating polymer substrate, a second insulating polymer substrate, and a heat-insulating film layer, wherein the first insulating polymer substrate and the second insulating polymer substrate are stacked, and the heat-insulating film layer is disposed between the first insulating polymer substrate and the second insulating polymer substrate.

[0016] The aforementioned protective film uses a first insulating polymer substrate and a second insulating polymer substrate with a heat-insulating film layer in between. The heat-insulating film layer provides heat insulation. The first and second insulating polymer substrates not only provide multiple insulation protections for the battery cells but also protect the heat-insulating film layer, ensuring its stable heat insulation performance. Thus, the protective film simultaneously provides insulation and heat insulation, giving the battery cells both physical protection against seepage and thermal isolation. Furthermore, because the protective film is tightly bonded to the battery cells, it provides relatively stable protection. Therefore, when used in batteries, this protective film can effectively prevent and delay battery thermal runaway.

[0017] In some embodiments, the stiffness of the heat insulation film layer is ≥190mm, and can be selected as 190mm~200mm.

[0018] The rigidity of the heat insulation film layer is within this range, while maintaining good flexibility, making it easy to roll up and wrap around the outside of the battery cell for better adhesion.

[0019] In some embodiments, the thickness of the heat insulation film layer is 0.2 mm to 0.5 mm.

[0020] By controlling the thickness of the heat insulation film within this range, good heat insulation can be achieved while maintaining a relatively small thickness.

[0021] In some embodiments, the thermal conductivity of the insulating film layer at 25°C is 0.01 W / (m·K) to 0.03 W / (m·K).

[0022] The heat insulation film has a low thermal conductivity, thus providing good heat insulation; it combines ultra-thin characteristics with high-efficiency heat insulation effect.

[0023] In some embodiments, the heat insulation film layer comprises one or more of an organic support material heat insulation pad and an inorganic support material heat insulation pad.

[0024] In some embodiments, the organic support material insulation pad includes one or more of porous silicone flexible insulation pads and polymer aerogel insulation pads; the inorganic support material insulation pad includes fiberglass cloth.

[0025] All of the above-mentioned heat insulation film layers have good flexibility and heat insulation properties. Compared with fiberglass cloth, porous silicon heat insulation layer and polymer aerogel heat insulation layer have better flexibility and heat insulation properties, and can better adhere to the insulating polymer substrate to form a flexible protective film.

[0026] In some embodiments, the edge region of the protective film includes a first insulating polymer substrate and a second insulating polymer substrate stacked together. Thus, compared to the main body region, the edge region omits the heat-insulating film layer, thereby making the thickness of the protective film in the edge region less than the thickness in the main body region.

[0027] In some embodiments, the housing includes a first wall and a second wall adjacent to the first wall, the main body region is located on the outer surface of the first wall, and the edge region is located on the outer surface of the second wall;

[0028] Optionally, the housing includes a third wall adjacent to the first wall and opposite to the second wall, and the protective film includes two edge regions located on opposite sides of the main body area, the two edge regions being located on the outer surfaces of the second wall and the third wall, respectively.

[0029] In some embodiments, the housing includes a body and an end cap, the body including a side plate and a bottom plate, the side plate being connected to the bottom plate, the bottom plate and the side plate enclosing a receiving cavity having an opening at one end, and the end cap being used to seal the opening;

[0030] The side plate is the first wall; of the bottom plate and the end cap, one is the second wall and the other is the third wall.

[0031] The aforementioned battery cell, through structural optimization of the protective film, has a thinner edge area and a thicker main body area on the outer surface of the side plate, while a thinner edge area is located on the outer surface of the bottom plate and / or end cap. This improves the problem of edge lifting at the top and / or bottom of the battery cell, enhances the stability of the adhesion between the protective film and the battery cell, enables the protective film to play a stable insulating role, and extends the service life of the battery cell.

[0032] A second aspect of this application provides a battery comprising the battery cell provided in the first aspect of this application.

[0033] A third aspect of this application provides an electrical device comprising at least one of the battery cell provided in the first aspect of this application and the battery provided in the second aspect of this application.

[0034] The battery and power supply device of this application include the battery cell provided in the first aspect of this application, and therefore have at least the same advantages as the battery cell.

[0035] Details of one or more embodiments of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0036] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0037] Figure 1 This is a schematic diagram of the structure of a battery cell according to one embodiment of this application;

[0038] Figure 2 This is an exploded structural diagram of a battery cell according to an embodiment of this application;

[0039] Figure 3 This is a schematic diagram of the structure of a battery cell according to one embodiment of this application;

[0040] Figure 4 This is a top view of the protective film according to an embodiment of this application.

[0041] Figure 5 for Figure 4 The right view of the protective film shown;

[0042] Figure 6 for Figure 4 The diagram shows a cross-sectional view of the protective film along the AA direction.

[0043] Figure 7 for Figure 4 The diagram shows a cross-sectional structure of the protective film in the BB direction;

[0044] Figure 8 This is a schematic diagram of the cross-sectional structure of the protective film in the AA direction according to another embodiment of this application;

[0045] Figure 9 This is a schematic diagram of the cross-sectional structure of the protective film in the AA direction according to another embodiment of this application;

[0046] Figure 10 This is a schematic diagram of the cross-sectional structure of the protective film in the AA direction according to another embodiment of this application;

[0047] Figure 11 This is a schematic diagram of the cross-sectional structure of the protective film in the BB direction according to another embodiment of this application;

[0048] Figure 12 This is a schematic diagram of the overall structure of the protective film according to an embodiment of this application;

[0049] Figure 13 This is a schematic diagram of a battery according to one embodiment of this application;

[0050] Figure 14 This is a schematic diagram of an electrical device in which a battery is used as a power source, according to one embodiment of this application.

[0051] Explanation of reference numerals in the attached figures:

[0052] 100. Protective film; 110. First insulating polymer substrate; 120. Second insulating polymer substrate; 130. Heat insulation film layer; 141. First adhesive layer; 142. Second adhesive layer; 143. Third adhesive layer; 144. Fourth adhesive layer; 150. Release film; 101. Main body area; 102. Edge area;

[0053] 20. Battery cell; 200. Casing; 210. Body; 211. Side plate; 212. Bottom plate; 220. End cap; 300. Electrode assembly;

[0054] 30. Battery; 32. Heat insulation pad;

[0055] 40. Electrical appliances; 42. Controllers; 44. Motors. Detailed Implementation

[0056] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0057] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0058] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0059] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0060] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0061] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0062] Currently, judging from market trends, the application of batteries is becoming increasingly widespread. Batteries, especially power batteries, are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as other fields. With the continuous expansion of the application areas of power batteries, the market demand is also constantly increasing.

[0063] A battery cell (also called a battery cell) is the smallest unit that makes up a battery. A battery can include one or more battery cells, and multiple battery cells can be connected in series, parallel, or a combination of both. A combination of both means that multiple battery cells are connected in both series and parallel.

[0064] Multiple battery cells can be interconnected and arranged in a specific order, then directly housed within a casing to assemble a battery. Alternatively, multiple battery cells can be first assembled into a battery module, then interconnected to form a whole, and finally housed within a casing to form a battery.

[0065] Regarding the aforementioned issue of poor adhesion stability between the protective film and the battery cell casing, this application found that a significant reason is that the edges of the protective film are prone to curling after folding, which affects the adhesion stability between the protective film and the casing, thus reducing the insulating effect of the protective film. In particular, the curling problem becomes more pronounced when the thickness of the protective film increases.

[0066] Therefore, this application optimizes the structure of the protective film, making the thickness of the protective film thinner at the edge, thus improving the problem of edge lifting at the top and / or bottom of the battery cell, enhancing the stability of the protective film's adhesion to the battery cell, enabling the protective film to play a stable insulating and isolating role, and extending the service life of the battery cell.

[0067] One or more embodiments of this application provide a battery cell, a protective film, a battery, and an electrical device.

[0068] Please see Figure 1 , Figure 2 and Figure 3 In a first aspect, this application provides a battery cell 20, including a housing 200, an electrode assembly 300, and a protective film 100 (e.g., Figure 3 (As shown).

[0069] The housing 200 has a receiving cavity.

[0070] The electrode assembly 300 is disposed within the receiving cavity.

[0071] Protective film 100 is provided on the outer surface of housing 200; please refer to Figure 3 and Figure 4 The protective film 100 includes a main body region 101 and an edge region 102 located on at least one side of the main body region 101. The thickness of the protective film 100 in the edge region 102 is less than the thickness in the main body region 101.

[0072] The aforementioned battery cell 20, through structural optimization of the protective film 100, makes the main body area 101 of the protective film 100 thicker and the edge area 102 of the protective film 100 thinner. The thinner edge area 102 is less prone to lifting, thus improving the edge lifting problem of the edge area 102, enhancing the stability of the adhesion between the protective film 100 and the battery cell 20, enabling the protective film 100 to play a stable insulating and isolating role, and extending the service life of the battery cell 20.

[0073] Understandably, edge region 102 refers to the area located at and encompassing the edge of protective film 100. Understandably, the main body region 101 is thicker than edge region 102, and a portion of the main body region 101 may be located at the edge of protective film 100, or it may not be located at the edge of protective film 100 at all.

[0074] Please see Figure 4 and Figure 5 In some embodiments of this application, the ratio of the thickness h1 of the protective film 100 in the edge region 102 to the thickness h2 in the main body region 101 is (0.05~0.8):1; as examples, it can be 0.05:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, or any value within the range formed by any two of the above point values ​​as endpoints. Further, the ratio of the thickness h1 of the protective film 100 in the edge region 102 to the thickness h2 in the main body region 101 is (0.05~0.5):1, and can be optionally (0.1~0.5):1. Controlling the thickness ratio of the two can better balance the good protective effect of the main body region 101 and the good anti-lifting performance of the edge region 102.

[0075] In some embodiments of this application, the thickness h1 of the protective film 100 in the edge region 102 is 0.05 mm to 0.3 mm, and can be selected as 0.05 mm to 0.2 mm or 0.1 mm to 0.3 mm. As an example, the thickness h1 of the protective film 100 in the edge region 102 can be 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, or any value within the range formed by any two of the above point values ​​as endpoints. Controlling the thickness h1 of the protective film 100 in the edge region 102 within the above range can give the edge region 102 better anti-lifting performance.

[0076] In some embodiments of this application, the thickness h2 of the protective film 100 in the main body region 101 is 0.1 mm to 2.0 mm, optionally 0.1 mm to 1.0 mm or 0.2 mm to 1.0 mm, optionally 0.2 mm to 0.5 mm. As an example, the thickness h2 of the protective film 100 in the main body region 101 can be 0.1 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2 mm, or any value within the range formed by any two of the above point values ​​as end values. By controlling the thickness h2 of the protective film 100 in the main body region 101 to be within the aforementioned range, the main body region 101 can have better insulation and protective effects. Further, the thickness h2 of the protective film 100 in the main body region 101 is 0.3mm to 1.0mm, and can be selected as 0.4mm to 1.0mm.

[0077] Please see Figure 4 In some embodiments of this application, the dimension W of the edge region 102 is ≥4mm in the direction from one end adjacent to the main body region 101 to the other end. Controlling the dimension W of the edge region 102 to ≥4mm can further improve the problem of edge region 102 lifting, improve the adhesion stability between the protective film 100 and the shell 200, and extend the service life of the battery cell 20. Understandably, the dimension W of the edge region 102 is the width of the edge region 102, and the direction from one end adjacent to the main body region 101 to the other end is the width direction of the edge region 102.

[0078] Taking the planar unfolded structure of the protective film 100 as a reference, the direction from one end of the edge region 102 adjacent to the main body region 101 to the other end is the extension direction from the main body region 101 to the edge region 102.

[0079] In one specific example, the planar unfolded structure of the protective film 100 is square, and further, rectangular. In one specific example, the planar unfolded structure of the main body area 101 is square, and further, rectangular; in one specific example, the planar unfolded structure of the edge area 102 is square, and further, rectangular.

[0080] The housing 200 includes a first wall and a second wall adjacent to the first wall. In some embodiments, a main body region 101 is located on the outer surface of the first wall, and an edge region 102 is located on the outer surface of the second wall. It is understood that the main body region 101 being located on the outer surface of the first wall may be partially or entirely located on the outer surface of the first wall; similarly, it is understood that the edge region 102 being located on the outer surface of the second wall may be partially or entirely located on the outer surface of the second wall, for example, at least the edges of the edge region 102 may be located on the outer surface of the second wall.

[0081] Further, the housing 200 includes a third wall adjacent to the first wall and opposite to the second wall. Further, the protective film 100 includes two edge regions 102 located on opposite sides of the main body region 101, the two edge regions 102 being located on the outer surfaces of the second and third walls, respectively. Understandably, the edge regions 102 being located on the outer surface of the third wall can be partially or entirely located on the outer surface of the third wall; for example, at least the edges of the edge regions 102 can be located on the outer surface of the third wall.

[0082] Please see Figure 2 and Figure 3 In some embodiments, the housing 100 includes a body 210 and an end cap 220. The body 210 includes a side plate 211 and a bottom plate 212. The side plate 211 is connected to the bottom plate 212. The bottom plate 212 and the side plate 211 enclose a receiving cavity with an opening at one end. The end cap 220 is used to seal the opening.

[0083] Furthermore, the side plate 211 is the first wall; of the bottom plate 212 and the end cap 220, one is the second wall and the other is the third wall. In other words, the main body area 101 is located on the outer surface of the side plate 211, and the edge area 102 is located on the outer surface of the bottom plate 212 and / or the end cap 220.

[0084] The aforementioned battery cell 20, through structural optimization of the protective film 100, makes the thickness of the edge area 102 of the protective film 100 thinner, and when the protective film 100 covers the outer surface of the housing 200, the thicker main body area 101 is provided on the outer surface of the side plate 211, and the thinner edge area 102 is provided on the outer surface of the bottom plate 212 and / or end cap 220. This improves the problem of edge lifting of the edge area 102 in the folded areas such as the top and / or bottom of the battery cell 20, enhances the stability of the adhesion between the protective film 100 and the battery cell 20, enables the protective film 100 to play a stable insulating and isolation role, and improves the service life of the battery cell 20.

[0085] Understandably, the edge region 102 can be located on the outer surface of the housing 200. For example, in other examples, both the main body region 101 and the edge region 102 may be located on the side plate 211, or the entire protective film 100 may be located on the side plate 211.

[0086] Furthermore, it is not recommended that the size W of the edge region 102 exceed the thickness of the battery cell 20, i.e., the thickness of the bottom plate 212 and / or end cap 220 of the housing 200. If the size W of the edge region 102 is too large, exceeding the thickness of the battery cell 20, the edge region 102 will not only be located on the bottom plate 212 and / or end cap 220 of the battery cell 20, but the edge region 102 extending beyond the protective film 100 will also adhere to the outer surface of the side plate 211 of the battery cell 20, easily leading to lifting problems and low material utilization. Therefore, the edge region 102 is located on the bottom plate 212 and / or end cap 220 of the housing 200 and does not extend beyond the bottom plate and / or end cap 220 of the housing 200; that is, the edge region 102 is located within the outer surface of the bottom plate 212 and / or end cap 220 of the housing 200. Specifically, based on the thickness of the battery cell 20, the size W of the edge region 102 can be adjusted within the range of 4 mm to the thickness of the battery cell 20.

[0087] In some examples, the size W of the edge region 102 is 4mm to 40mm, and can be selected as 8mm to 40mm. In some examples, the size W of the edge region 102 is 4mm to 20mm. In some examples, the size W of the edge region 102 is 4mm to 15mm, and can be selected as 4mm to 8mm.

[0088] The edge region 102 is located on the outer surface of the base plate 212 and / or the end cap 220, meaning that the edge region 102 may be located on one or both of the base plate 212 and the end cap 220, and may be located on part or all of the outer surface thereon.

[0089] In some examples, edge region 102 is located on the outer surface of the base plate; in some examples, edge region 102 is located on a portion of the outer surface of the base plate 212. In some examples, edge region 102 is located on a portion of the outer surface of the end cap 220 to provide space for exposing the pole of the end cap.

[0090] Please see Figure 4 and Figure 5 In some embodiments of this application, the protective film 100 includes two edge regions 102 located on opposite sides of the main body region 101. Further, the main body region 101 is disposed on the outer surface of the side plate 211, and the two edge regions 102 are respectively located on the outer surfaces of the bottom plate and the end cap 220.

[0091] Understandably, the protective film 100 may include one or more layers of insulating polymer substrate. Understandably, without changing the layer structure of the protective film 100, the thickness difference between the edge region 102 and the main body region 101 can be achieved by adjusting the thickness of the protective film 100 in the edge region 102 and the main body region 101, or by adjusting the number of layers in the layer structure of the protective film 100.

[0092] In some embodiments, the main body region 101 of the protective film 100 includes a first insulating polymer substrate 110 and a heat insulation film layer 130, and the edge region 102 of the protective film 100 includes the first insulating polymer substrate 110 but does not contain the heat insulation film layer 130. Therefore, the thickness of the protective film 100 in the edge region 102 is less than the thickness in the main body region 101.

[0093] Please see Figure 5 and Figure 6 In some embodiments of this application, the main body area 101 of the protective film 100 includes a first insulating polymer substrate 110, a second insulating polymer substrate 120 and a heat insulation film layer 130. The first insulating polymer substrate 110, the second insulating polymer substrate 120 and the heat insulation film layer 130 are stacked, and the heat insulation film layer 130 is disposed between the first insulating polymer substrate 110 and the second insulating polymer substrate 120.

[0094] Traditional protective films are generally composed of polymer substrates and are adhered to the outside of battery cells via an adhesive layer. Their main function is to insulate the battery cells and prevent electrolyte leakage. The protective film 100 of this application, while retaining the insulating properties of traditional protective films, incorporates a heat-insulating film layer, giving it heat-insulating properties. The heat-insulating film layer 130 provides heat insulation. The first insulating polymer substrate 110 and the second insulating polymer substrate 120 not only provide multiple layers of insulation protection for the battery cells 20 but also protect the heat-insulating film layer 130, ensuring its stable heat-insulating performance. Thus, the protective film 100 simultaneously provides insulation and heat insulation, giving the battery cells 20 both physical protection against seepage and thermal isolation, thereby improving the battery's insulation and heat-insulating performance and effectively preventing and delaying battery thermal runaway. Furthermore, due to the good flexibility of the protective film 100, it adheres tightly to the battery cells 20, providing relatively stable protection.

[0095] By placing the heat insulation film 130 in the middle with the first insulating polymer substrate 110 and the second insulating polymer substrate 120, it is possible to prevent dust and electrolyte from seeping into the heat insulation film 130 and causing the heat insulation performance of the heat insulation film 130 to deteriorate. Therefore, the heat insulation film 130 can be protected so that it can stably perform its heat insulation performance.

[0096] In some embodiments, the stiffness of the heat insulation film layer 130 is ≥190mm; as an example, the stiffness of the heat insulation film layer 130 may be 190mm, 192mm, 195mm, 198mm, 200mm or any value within the range formed by any two of the above point values ​​as end values; further, the stiffness of the heat insulation film layer 130 is 190mm~200mm.

[0097] In this application, the test method for the stiffness of the heat insulation film layer 130 is as follows. Ambient temperature: 22.8℃, humidity: 56.4%RH, ambient temperature and humidity requirements: temperature 25±3℃, humidity 45%~75%RH; refer to GB / T 7689.4-2013, specifically as follows: (1) Sample: size 250mm*50mm*1mm, the initial thickness is tested according to method 4.3.2 in GB / T 7689.4-2013; (2) Test method: the sample is placed flat on a high platform, one end is fixed to the platform 50mm, and the other end is suspended 200mm. The drooping height of the suspended end is measured to obtain the stiffness.

[0098] The rigidity of the heat insulation film layer 130 has good flexibility within this range, which allows the battery protective film 100 to have good overall flexibility while maintaining a relatively thin thickness, making it easy to roll up and also easy to wrap around the outside of the battery cell 20, so as to better fit with the battery cell 20. Understandably, the protective film 100 is a flexible film layer.

[0099] The elastic modulus of the heat insulation film layer 130 has good flexibility within this range, which allows the protective film 100 to have good overall flexibility while also having a relatively thin thickness, making it easy to roll up and also easy to wrap around the outside of the battery cell 20, so as to better fit with the battery cell 20.

[0100] Please continue reading. Figure 5 and Figure 7 In some embodiments of this application, the heat-insulating film layer 130 is not provided in the edge region 102. The edge region 102 of the protective film 100 includes a first insulating polymer substrate 110 and a second insulating polymer substrate 120 stacked together. Further, in the edge region 102, the heat-insulating film layer 130 is not provided between the first insulating polymer substrate 110 and the second insulating polymer substrate 120; the two are directly connected by hot pressing or an adhesive layer. Thus, compared to the main body region 101, the heat-insulating film layer 130 is omitted in the edge region 102, thereby making the thickness of the protective film 100 in the edge region 102 less than the thickness of the main body region 101.

[0101] Furthermore, in some examples, the battery also includes a water-cooling component. For example, the water-cooling component is located at the bottom of the battery cell 20, i.e., on the outer side of the bottom plate of the battery cell 20. The edge area 102 does not have a heat insulation film layer 130, which does not affect the cooling effect of the water-cooling component and is beneficial to improving the heat dissipation effect of the battery cell 20. In addition, the edge area 102 without a heat insulation film layer 130 has better flexibility and is beneficial for folding operations.

[0102] In some embodiments of this application, the thickness of the heat insulation film layer 130 is 0.2 mm to 0.5 mm. Controlling the thickness of the heat insulation film layer 130 within this range allows for good heat insulation while maintaining a relatively small thickness. As an example, the thickness of the heat insulation film layer 130 is 0.2 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, or any two of the above values ​​as endpoints. Further, the thickness of the heat insulation film layer 130 is 0.2 mm to 0.35 mm.

[0103] In this paper, the following method can be used to detect the thickness of each part of the protective film 100. The equipment used is a Mitutoyo 547-301 thickness gauge with an accuracy of ≤0.01mm. During the test, the test surfaces of the protective film 100 and the Mitutoyo 547-301 thickness gauge should be kept parallel to the ground. The test positions are the four corners and the central area, a total of 5 points. The average value of the 5 points is taken as the test value.

[0104] In some embodiments of this application, the thermal conductivity of the heat insulation film 130 at 25°C is 0.01 W / (m·K) to 0.03 W / (m·K). The heat insulation film 130 has a low thermal conductivity, thus providing good heat insulation while maintaining both ultra-thin characteristics and high-efficiency heat insulation.

[0105] As an example, the thermal conductivity of the heat insulation film layer 130 at 25°C can be 0.01 W / (m·K), 0.015 W / (m·K), 0.02 W / (m·K), 0.025 W / (m·K), 0.03 W / (m·K), or within a range defined by any two of the above values ​​as endpoints. Further, the thermal conductivity of the heat insulation film layer 130 at 25°C is 0.01 W / (m·K) to 0.02 W / (m·K).

[0106] In some embodiments of this application, the heat insulation film layer 130 comprises a laminate of one or more of organic support material heat insulation pads and inorganic support material heat insulation pads. Further, the organic support material heat insulation pad includes, but is not limited to, one or more of porous silicone flexible heat insulation pads and polymer aerogel heat insulation pads; further, the inorganic support material heat insulation pad includes, but is not limited to, fiberglass cloth. Further, the heat insulation film layer 130 comprises a laminate of one or more of porous silicone flexible heat insulation pads, polymer aerogel heat insulation pads, and fiberglass cloth. The above-mentioned heat insulation film layer 130 has a porous structure and possesses good flexibility and heat insulation performance. By placing the heat insulation film layer 130 in the middle through the first insulating polymer substrate 110 and the second insulating polymer substrate 120, the problem of dust and electrolyte leakage into the porous structure of the heat insulation film layer 130, leading to a significant deterioration in the heat insulation performance of the heat insulation film layer 130, can be prevented. Therefore, the heat insulation film layer 130 can be protected, allowing it to stably perform its heat insulation performance.

[0107] Furthermore, porous silica flexible thermal insulation pads include, but are not limited to, porous vacuum silica thermal insulation cotton. Porous vacuum silica thermal insulation cotton is a cross-linked sheet-like flexible thermal insulation material comprising a polymer framework and nanoporous vacuum silica. Further, porous vacuum silica thermal insulation cotton is a flexible sheet insulation material prepared by combining porous vacuum silica oxide material with a polymer framework material through a vacuum cross-linking, vaporization, and high-pressure drying process.

[0108] When the heat insulation film layer 130 includes the above-mentioned multiple layers, any two adjacent layers can be bonded together by an adhesive layer.

[0109] Compared to fiberglass cloth, porous silicone flexible thermal insulation pads and polymer aerogel thermal insulation pads offer better flexibility and thermal insulation properties, allowing for better adhesion to an insulating polymer substrate to form a flexible protective film. Optionally, the thermal insulation film layer 130 comprises one or more layers of porous silicone flexible thermal insulation pads and polymer aerogel thermal insulation pads. More preferably, the thermal insulation film layer 130 comprises a porous silicone flexible thermal insulation pad.

[0110] In some examples, the insulating film layer 130 is a stack of one or more of porous silicone flexible insulating pads, polymer aerogel insulating pads, and fiberglass cloth.

[0111] The polymer aerogel insulation pad includes, but is not limited to, one or more of the following laminates: melamine aerogel insulation pad, PI aerogel insulation pad (i.e., polyimide aerogel insulation pad), and PET aerogel insulation pad (polyethylene terephthalate aerogel insulation pad). When the polymer aerogel insulation pad includes multiple laminates as described above, any two adjacent layers can be bonded together by an adhesive layer.

[0112] Please see Figure 8In some embodiments of this application, the protective film 100 further includes a first adhesive layer 141 and a release film 150, with the protective film 100 disposed on the outer surface of the housing 200 via the first adhesive layer. Further, the release film 150 is disposed on the side of the second insulating polymer substrate 120 away from the heat-insulating film layer 130, and the first adhesive layer 141 is located between the second insulating polymer substrate 120 and the release film 150. That is, the first adhesive layer 141 adheres the release film 150 to one side of the second insulating polymer substrate 120. Thus, in use, the release film 150 can be removed to expose the first adhesive layer 141, and the protective film 100 can be adhered to a target location, such as the outer surface of the battery cell 20, via the first adhesive layer 141. Understandably, in the battery cell, the protective film 100 does not contain the aforementioned release film 150. Furthermore, when the protective film 100 is rolled up, the release film 150 can act as a separator between the layers of the protective film 100, serving an anti-adhesion function.

[0113] Furthermore, the first adhesive layer 141 includes, but is not limited to, one or more layers of acrylic pressure-sensitive adhesive (i.e., acrylic pressure-sensitive adhesive), polyurethane adhesive, and silicone adhesive. These adhesive layers have strong adhesion, which can improve the overall peel strength of the protective film 100. Optionally, the first adhesive layer 141 includes an acrylic pressure-sensitive adhesive layer. The first adhesive layer 141 is used to bond the battery cell 20. Using an acrylic pressure-sensitive adhesive layer is beneficial to improving the adhesion to the battery cell 20. The silicone adhesive layer is heat-resistant and has high structural strength.

[0114] Further, the thickness of the first adhesive layer 141 is 0.01mm to 0.4mm. As an example, the thickness of the first adhesive layer 141 is 0.01mm, 0.02mm, 0.03mm, 0.035mm, 0.036mm, 0.04mm, 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, or any two of the above values ​​as endpoints. Optionally, the thickness of the first adhesive layer 141 is 0.01mm to 0.036mm.

[0115] Furthermore, the release film 150 includes, but is not limited to, silicone release paper.

[0116] Furthermore, the thickness of the release film 150 is 0.2 mm.

[0117] Please see Figure 9 or Figure 10 In some embodiments of this application, the protective film 100 further includes a second adhesive layer 142, which is disposed between the first insulating polymer substrate 110 and the heat insulation film layer 130. By using the second adhesive layer 142 to bond the first insulating polymer substrate 110 and the heat insulation film layer 130 together, the adhesion between the first insulating polymer substrate 110 and the heat insulation film layer 130 can be improved.

[0118] Alternatively, please see Figure 6 or Figure 8 In some embodiments of this application, the first insulating polymer substrate 110 and the heat insulation film layer 130 are directly bonded together, for example by hot pressing or other methods. The first insulating polymer substrate 110 is directly bonded to the heat insulation film layer 130 under hot pressing.

[0119] Please continue reading. Figure 9 or Figure 10 In some embodiments of this application, the protective film 100 further includes a third adhesive layer 143, which is disposed between the second insulating polymer substrate 120 and the heat insulation film layer 130. Thus, the third adhesive layer 143 adheres the second insulating polymer substrate 120 and the heat insulation film layer 130 together, thereby improving the adhesion between them.

[0120] Alternatively, please see Figure 6 or Figure 8 In some embodiments of this application, the second insulating polymer substrate 120 and the heat insulation film layer 130 are directly bonded together, for example by hot pressing or other methods, and the second insulating polymer substrate 120 is directly bonded to the heat insulation film layer 130 by hot pressing.

[0121] Please continue reading. Figure 7 In some embodiments of this application, the first insulating polymer substrate 110 and the second insulating polymer substrate 120 are directly bonded together at the edge region 102 of the protective film 100, for example, by direct pressing. Understandably, the edge region 102 of the protective film 100 may also optionally include a release film 150.

[0122] Please continue reading. Figure 11 In other embodiments of this application, the edge region 102 of the protective film 100 further includes a fourth adhesive layer 144, which is disposed between the first insulating polymer substrate 110 and the second insulating polymer substrate 120. Thus, the fourth adhesive layer 144 adheres the first insulating polymer substrate 110 and the second insulating polymer substrate 120 together, thereby improving the adhesion between the two substrates. Understandably, the edge region 102 of the protective film 100 may also optionally include a release film 150.

[0123] Furthermore, when the structure of the main area 101 is as follows: Figure 10As shown, when the material includes a first insulating polymer substrate 110, a second adhesive layer 142, a heat-insulating film layer 130, a third adhesive layer 143, a second insulating polymer substrate 120, a first adhesive layer 141, and a release film 150 stacked sequentially, the fourth adhesive layer 144 of the edge region 102 can be formed in the same layer as one or both of the second adhesive layer 142 and the third adhesive layer 143 in the same process. Furthermore, the release film 150 of the edge region 102 and the release film 150 of the main body region 101 can be separately disposed, i.e., separated from each other, or they can be continuous film layers, i.e., a continuous whole film layer between the two release films 150. Furthermore, the adhesive layers in the edge region 102 and the main body region 101 used to bond the release film 150 and the second insulating polymer substrate 120 can be formed in the same layer in the same process, for example, both being the first adhesive layer 141.

[0124] Furthermore, the second adhesive layer 142 includes, but is not limited to, one or more of the following: an acrylic pressure-sensitive adhesive layer, a polyurethane adhesive layer, and a silicone adhesive layer.

[0125] Furthermore, the third adhesive layer 143 includes, but is not limited to, one or more of the following: an acrylic pressure-sensitive adhesive layer, a polyurethane adhesive layer, and a silicone adhesive layer.

[0126] Further, the fourth adhesive layer 144 includes, but is not limited to, one or more laminates of acrylic pressure-sensitive adhesive layers, polyurethane adhesive layers, and silicone adhesive layers. Understandably, the fourth adhesive layer 144 may be formed in the same process as the second adhesive layer 142 or the third adhesive layer 143. Further, the material of the fourth adhesive layer 144 may be the same as the material of the second adhesive layer 142 or the third adhesive layer 143. Further, the thickness of the fourth adhesive layer 144 may be the same as the thickness of the second adhesive layer 142 or the third adhesive layer 143.

[0127] Further, the thickness of the second adhesive layer 142 is 0.01mm to 0.4mm; as an example, the thickness of the second adhesive layer 142 is 0.01mm, 0.02mm, 0.03mm, 0.034mm, 0.035mm, 0.036mm, 0.04mm, 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, or within the range formed by any two of the above point values ​​as endpoints. Optionally, the thickness of the second adhesive layer 142 is 0.01mm to 0.034mm.

[0128] Further, the thickness of the third adhesive layer 143 is 0.01 mm to 0.4 mm. As an example, the thickness of the third adhesive layer 143 is 0.01 mm, 0.02 mm, 0.03 mm, 0.034 mm, 0.035 mm, 0.036 mm, 0.04 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, or any two of the above values ​​as endpoints. Optionally, the thickness of the third adhesive layer 143 is 0.01 mm to 0.034 mm.

[0129] Further, the thickness of the fourth adhesive layer 144 is 0.01 mm to 0.4 mm. As an example, the thickness of the third adhesive layer 143 is 0.01 mm, 0.02 mm, 0.03 mm, 0.034 mm, 0.035 mm, 0.036 mm, 0.04 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, or any two of the above values ​​as endpoints. Optionally, the thickness of the third adhesive layer 143 is 0.01 mm to 0.034 mm.

[0130] In some embodiments of this application, the first insulating polymer substrate 110 includes one of a PI (polyimide) substrate, a PP (polypropylene) substrate, and a PET (polyethylene terephthalate) substrate. In some embodiments of this application, the second insulating polymer substrate 120 includes one of a PI substrate, a PP substrate, and a PET substrate. These insulating polymer substrates not only have good insulation properties but also excellent resistance to acids and alkalis, corrosion, high voltage, and leave no residue. Therefore, the protective film 100 can be used not only as an insulating barrier but also as an anti-sticking film or a protective film.

[0131] In some embodiments of this application, the thickness of the first insulating polymer substrate 110 is 0.01 mm to 0.15 mm; as an example, the thickness of the first insulating polymer substrate 110 is 0.01 mm, 0.02 mm, 0.025 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.1 mm, 0.15 mm, or within a range formed by any two of the above values ​​as endpoints. Optionally, the thickness of the first insulating polymer substrate 110 is 0.025 mm to 0.05 mm.

[0132] In some embodiments of this application, the thickness of the second insulating polymer substrate 120 is 0.01 mm to 0.15 mm. As an example, the thickness of the second insulating polymer substrate 120 is 0.01 mm, 0.02 mm, 0.025 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.1 mm, 0.15 mm, or within a range defined by any two of the above values ​​as endpoints. Optionally, the thickness of the second insulating polymer substrate 120 is 0.025 mm to 0.05 mm.

[0133] exist Figure 6 or Figure 8 In a specific example, the first insulating polymer substrate 110 and the heat insulation film layer 130 are directly bonded together, and the second insulating polymer substrate 120 and the heat insulation film layer 130 are also directly bonded together. Further, in Figure 7 In a specific example, the protective film 100 further includes a first adhesive layer 141 and a release film 150, wherein the first adhesive layer 141 adheres the release film 150 to one side of the second insulating polymer substrate 120. Further, the first adhesive layer 141 is an acrylic pressure-sensitive adhesive layer.

[0134] exist Figure 9 or Figure 10 In a specific example, the protective film 100 further includes a second adhesive layer 142 and a third adhesive layer 143. The second adhesive layer 142 is disposed between the first insulating polymer substrate 110 and the heat insulation film layer 130, and the third adhesive layer 143 is disposed between the second insulating polymer substrate 120 and the heat insulation film layer 130. Further, in Figure 10 In a specific example, the protective film 100 further includes a first adhesive layer 141 and a release film 150, wherein the first adhesive layer 141 adheres the release film 150 to one side of the second insulating polymer substrate 120. Further, the first adhesive layer 141 is an acrylic pressure-sensitive adhesive layer; further, the second adhesive layer 142 and the third adhesive layer 143 are silicone adhesive layers.

[0135] In some embodiments of this application, the protective film 100 is adhered to the housing 200 by a first adhesive layer 141 disposed on the side of the second insulating polymer substrate 120 away from the heat insulation film layer 130.

[0136] Please see Figure 12 In some embodiments of this application, the protective film 100 is a roll before use. The protective film 100 is a strip-shaped flexible film layer; making it into a roll facilitates storage. In use, the protective film 100 is unrolled into a strip and wrapped around the outside of the battery cell 20. A single wrapping provides both insulation and heat insulation for the battery cell 20.

[0137] Specifically, in combination Figure 4The length direction of the main body area 101 and the edge area 102 is the same as the length direction of the strip-shaped protective film 100. The length direction of the strip-shaped protective film 100 is perpendicular to the width direction of the main body area 101 and the edge area 102.

[0138] In one specific example, a strip-shaped protective film 100 is rolled and wrapped along the entire outer surface of the side plate 211 of the body 210 in the longitudinal direction; and the width of the protective film 100 is greater than the height of the side plate 211 of the body 210. The protective film 100 covers the side plate 211 of the body 210, and the excess portion in the width direction covers at least part of the outer surface of the bottom plate and / or the outer surface of the end cap. This can better cover the edges of the battery cell 20, thereby better preventing electrolyte leakage.

[0139] Furthermore, the main body region 101 covers the side plate 211 of the main body 210, and the edge region 102 covers at least a portion of the outer surface of the base plate and the outer surface of the end cap. Furthermore, the width of the main body region 101 is equal to the height of the side plate 211 of the main body 210, such that the main body region 101 covers the side plate 211 of the main body 210 and is located within the outer surface of the side plate 211 of the main body 210. Furthermore, the main body region 101 overlaps with the outer contour of the side plate 211 of the main body 210, such that the main body region 101 completely covers the entire outer surface of the side plate 211, providing insulation and heat protection.

[0140] It is understood that the shape of the battery cell 20 includes, but is not limited to, square and cylindrical shapes, and the shape of the casing 200 includes, but is not limited to, square and cylindrical shapes. The protective film 100 can be fitted according to the shape of the battery cell 20.

[0141] For example, Figure 1 and Figure 2 The example shown is a square-structured battery cell 20. Both the battery cell 20 and the housing 200 are square in shape. The body 210 of the housing 200 includes a base plate and four side plates 211 connected to the base plate. Two of the larger side plates 211 form two relatively large sidewalls on the large surface of the battery cell 20. Specifically, a protective film 100 is disposed on the outer surfaces of the four side plates 211, as well as on a portion of the outer surface of the base plate and a portion of the outer surface of the end cap 220.

[0142] It is understandable that when two adjacent battery cells 20 are arranged, they are positioned with the larger sidewall facing each other.

[0143] It is understood that if the battery cell 20 and the casing 200 are cylindrical, the casing 200 includes cylindrical sidewalls (i.e., larger sidewalls) that form the large surface of the battery cell 20.

[0144] Furthermore, the housing 200 is a cuboid housing. The opening direction of the housing 200 is the height direction of the housing. In a specific example, one end of the housing 200 is open, and the open end is the top. In a specific example, both ends of the housing have openings, and the two openings are arranged opposite each other along the height direction of the housing.

[0145] As a non-limiting example, the height of the housing 200 is 80mm to 210mm; as a non-limiting example, the length of the housing 200 is 90mm to 240mm; as a non-limiting example, the width of the housing 200 (i.e., the thickness of the battery cell 20) is 20mm to 80mm.

[0146] Furthermore, the battery cell 20 and the casing 200 are cuboid casings. The larger side surface of the battery cell 20 is perpendicular to the aforementioned width direction, and this larger side surface is the side surface formed by the two sides in the aforementioned length and height directions.

[0147] As a further, non-limiting example, the wall thickness of the housing is 0.5 mm to 0.8 mm.

[0148] Furthermore, the housing 200 is an aluminum alloy housing; for example, a three-series aluminum alloy housing or a five-series aluminum alloy housing.

[0149] Furthermore, the aluminum alloy of the three-element aluminum alloy shell comprises the following components by mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other individual elements ≤ 0.03%.

[0150] Furthermore, the aluminum alloy of the five-series aluminum alloy shell comprises the following components by mass percentage: aluminum ≥ 96.7%, copper ≤ 0.05% ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other individual element components ≤ 0.05%, and other element total components ≤ 0.15%.

[0151] Furthermore, an electrode post is provided protruding on the end cap 220. The electrode post is a component used to electrically connect with the electrode assembly 300 to conduct electrical energy from the electrode assembly 300.

[0152] Furthermore, during the connection process between the electrode assembly 300 and the electrode post, since the area where the electrode post can connect with the electrode assembly 300 is relatively small, a welded pressure ring is usually required to ensure a stable connection between the electrode assembly 300 and the electrode post. After setting the welded pressure ring, a sealing ring is required to increase the sealing between the electrode post and the end cap 220. In addition, to prevent the electrode assembly 300 from directly contacting other parts of the end cap 220 besides the electrode post, upper and lower plastic seals are also required between the electrode assembly 300 and the end cap 220 for insulation.

[0153] In addition, since the electrode assembly 300 can be a stacked electrode assembly or a wound electrode assembly, that is, it is formed by stacking or winding multiple layers of positive electrode sheets, negative electrode sheets, and separator films, the electrode assembly 300 is also connected in multiple layers simultaneously when connected to the electrode post. However, the area that the electrode post can connect to the electrode assembly 300 is relatively small. In order to enable the multi-layer structure of the electrode assembly 300 to connect more completely with the electrode post, a transition piece is also needed between the electrode assembly 300 and the electrode post to achieve mutual connection between the two.

[0154] Please see Figure 13 In a third aspect of this application, a battery 30 is provided, comprising the battery cell provided in the second aspect of this application.

[0155] In some embodiments, the battery 30 also includes a housing, in which individual battery cells are housed.

[0156] Furthermore, the battery 30 includes a plurality of battery cells, at least one of which is the aforementioned battery cell 20. In a specific example, all of the plurality of battery cells are the aforementioned battery cell 20.

[0157] Multiple battery cells in battery 30 can be connected in series, parallel, or a combination thereof. A combination thereof refers to multiple battery cells being connected in both series and parallel configurations.

[0158] Multiple battery cells can be interconnected and arranged in a certain order, and then directly placed into a housing to assemble a battery. Alternatively, multiple battery cells can be first assembled into a battery module, and then the multiple battery modules can be interconnected to form a whole. Finally, the entire battery module can be placed into a housing to form a battery 30.

[0159] In some embodiments, the battery 30 further includes a heat insulation pad 32 disposed between adjacent battery cells 20 and / or between the heat insulation pad 32 and the inner wall of the housing.

[0160] In some embodiments, the heat insulation pad 32 is disposed on the outer side of the larger sidewall of the battery cell 20. Further, the heat insulation pad 32 is disposed between the larger sidewalls of two adjacent battery cells 20.

[0161] A fourth aspect of this application provides an electrical device comprising at least one of the battery cell provided in the second aspect of this application and the battery provided in the third aspect of this application.

[0162] The aforementioned battery can be a power source for an electrical device or an energy storage unit for that device. Electrical devices can include, but are not limited to, mobile devices, electric vehicles, electric trains, ships, and satellites. Mobile devices can be, for example, mobile phones and laptops; electric vehicles can be, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc., but are not limited to these.

[0163] As an electrical device, individual battery cells or batteries can be selected according to its usage requirements.

[0164] Figure 14 This is an example of an electrical device 40. Electrical device 40 is a vehicle, which can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery 30 is installed inside the vehicle, and the battery 30 can be located at the bottom, front, or rear of the vehicle. The battery 30 can be used to power the vehicle; for example, the battery 30 can serve as the vehicle's operating power source. The vehicle may also include a controller 42 and a motor 44. The controller 42 is used to control the battery 30 to supply power to the motor 44, for example, to meet the power needs of the vehicle during starting, navigation, and driving.

[0165] In some embodiments of this application, the battery 30 can not only serve as the operating power source for the vehicle, but also as the driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0166] In some embodiments of this application, the electrical device 40 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the electrical device 40, a battery formed by multiple battery cells can be used as the power source.

[0167] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use a single battery cell as their power source.

[0168] The following are specific examples.

[0169] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0170] Example 1

[0171] like Figures 1 to 3 As shown, the battery cell of Embodiment 1 includes a housing 200, an electrode assembly 300, and a protective film 100. The housing 100 includes a body 210 and an end cap 220. The body 210 includes a side plate 211 and a bottom plate 212. The side plate 211 is connected to the bottom plate 212. The bottom plate 212 and the side plate 211 enclose a receiving cavity with an opening at one end. The end cap 220 is used to seal the opening. The electrode assembly 300 is disposed in the receiving cavity.

[0172] like Figure 4 As shown, the protective film 100 includes two edge regions 102 located on opposite sides of the main body region 101; the structure of the main body region 101 is as follows: Figure 10 As shown, the structure includes a first insulating polymer substrate 110, a second adhesive layer 142, a heat insulation film layer 130, a third adhesive layer 143, a second insulating polymer substrate 120, a first adhesive layer 141, and a release film 150, which are stacked sequentially. The edge region 102 also includes the first insulating polymer substrate 110, the second adhesive layer 142, the second insulating polymer substrate 120, the first adhesive layer 141, and the release film 150, which are stacked sequentially. The heat insulation film layer 130 and the third adhesive layer 143 of the main body region 101 are omitted. In addition, the first insulating polymer substrate 110, the second adhesive layer 142, the second insulating polymer substrate 120, the first adhesive layer 141, and the release film 150 are continuous film layers in a one-to-one correspondence between the main body region 101 and the edge region 102.

[0173] The first insulating polymer substrate 110 and the second insulating polymer substrate 120 are PET substrates with a thickness of 0.05 mm; the heat insulation film layer 130 is a porous vacuum silicone heat insulation cotton with a thickness of 0.35 mm; the stiffness of the heat insulation film layer 130 (test method as above) is 195 mm; the thermal conductivity of the heat insulation film layer 130 at 25℃ is 0.018 W / (m·K); the second adhesive layer 142 and the third adhesive layer 143 are silicone adhesive layers with a thickness of 0.035 mm; the first adhesive layer 141 is an acrylic pressure-sensitive adhesive layer with a thickness of 0.034 mm; and the release film 150 is an organosilicon release paper with a thickness of 0.2 mm.

[0174] The steps for attaching the protective film 100 to the housing 200 are as follows: The protective film 100 with the release film removed is attached to the outer surface of the housing 100. Specifically, the strip-shaped protective film 100 is rolled lengthwise and completely covers the outer surface of the side plate 211 of the body 210; the width of the main body area 101 of the protective film 100 is equal to the height of the side plate 211 of the body 210, the main body area 101 covers the side plate 211 of the body 210, and the two edge areas 102 are respectively attached to the outer surfaces of the base plate 212 and the side plate 211, as shown below. Figure 3 As shown. Specifically, the width of the edge region 102 is 4 mm.

[0175] The height of the housing 200 is 173mm, the length of the housing 200 is 200mm, and the width of the housing 200 (i.e. the thickness of the battery cell 20) is 56.9mm.

[0176] Example 2

[0177] It is basically the same as Example 1, except that the structure of the edge region 102 is adjusted. The structure of the edge region 102 includes a first insulating polymer substrate 110, a second insulating polymer substrate 120 and a first adhesive layer 141 stacked in sequence. The second adhesive layer 142 in Example 1 is omitted. It is formed by hot pressing. The thickness of the edge region 102 is different.

[0178] Example 3

[0179] It is basically the same as Example 1, except that the width of the edge area 102 is adjusted, as shown in Table 1.

[0180] Example 4

[0181] It is basically the same as Example 1, except that the thickness of the heat insulation film layer 130 is adjusted to be different, specifically a porous vacuum silicone heat insulation cotton with a thickness of 0.2 mm.

[0182] Example 5

[0183] It is basically the same as Example 1, except that the thickness of the heat insulation film layer 130 is adjusted to be different, specifically a porous vacuum silicone heat insulation cotton with a thickness of 0.5 mm.

[0184] The following are performance tests.

[0185] (1) Test of warping performance

[0186] The protective film is applied to the casing with a pressure of 2 kg, and rolled back and forth twice. Test method: The battery cell is left to stand at room temperature (25±3℃) for 48 hours. Afterwards, observe for any peeling and measure the height and length of any peeling points using a steel ruler.

[0187] If the observed area does not show any peeling; or if the peeling height is ≤4mm and the peeling length is ≤7mm, the area is considered to have passed the peeling test and is not counted as "peeling"; if the edge areas of the protective film of the battery cell all pass the peeling test, the battery cell is considered to have passed the peeling test and is not counted as "peeling".

[0188] If the height of the raised area is ≤4mm or the length of the raised area is ≤7mm, then the area is considered to have failed the raised area test and is counted as "raised area". If any area of ​​the edge region of the protective film of a battery cell fails the raised area test, then the battery cell is considered to have failed the raised area test and is counted as "raised area".

[0189] Table 1 shows the test results using 100 battery cells. The lift probability refers to the percentage of battery cells that failed the lift test out of the total number of battery cells tested.

[0190] Table 1 shows some parameters and test results of the battery cells prepared in each embodiment and comparative example. In Table 1, the thickness of the main body region 101 and the edge region 102 refers to the thickness in the battery cell, excluding the thickness of the release film; the thickness ratio refers to the ratio of the thickness of the edge region 102 to the thickness of the main body region 101 in the battery cell.

[0191] Table 1

[0192]

[0193] As can be seen from the above embodiments, the battery cell of this application optimizes the structure of the protective film, making the thickness of the main body area of ​​the protective film larger and the thickness of the edge area of ​​the protective film thinner. The thinner edge area is less likely to lift (the probability of lifting without a thinner edge area is about 20%). This improves the edge lifting problem, enhances the stability of the adhesion between the protective film and the battery cell, enables the protective film to play a stable insulating and isolating role, and improves the service life of the battery cell.

[0194] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0195] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery cell, characterized in that, include: The shell has a receiving cavity; The electrode assembly is disposed within the receiving cavity; as well as A protective film is disposed on the outer surface of the housing. The protective film includes a main body area and an edge area located on at least one side of the main body area. The thickness of the protective film in the edge area is less than the thickness in the main body area.

2. The battery cell according to claim 1, characterized in that, The thickness of the protective film in the edge region is 0.05 mm to 0.3 mm; and / or, The thickness of the protective film in the main body area is 0.1mm to 2.0mm, and can be selected as 0.2mm to 1.0mm.

3. The battery cell according to any one of claims 1 to 2, characterized in that, The ratio of the thickness of the protective film in the edge region to the thickness in the main body region is (0.05~0.8):1, and can be optionally (0.05~0.5):

1.

4. The battery cell according to any one of claims 1 to 3, characterized in that, The size of the edge region is ≥4mm, and can be selected as 4mm~40mm, from one end of the edge region adjacent to the main body region to the other end.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The main body area of ​​the protective film includes a first insulating polymer substrate, a second insulating polymer substrate, and a heat insulation film layer. The first insulating polymer substrate and the second insulating polymer substrate are stacked, and the heat insulation film layer is disposed between the first insulating polymer substrate and the second insulating polymer substrate.

6. The battery cell according to claim 5, characterized in that, The stiffness of the heat insulation film layer is ≥190mm, and can be selected as 190mm~200mm.

7. The battery cell according to any one of claims 5 to 6, characterized in that, The thickness of the heat insulation film layer is 0.2mm~0.5mm.

8. The battery cell according to any one of claims 5 to 7, characterized in that, The thermal conductivity of the heat insulation film layer at 25°C is 0.01 W / (m·K)~0.03 W / (m·K).

9. The battery cell according to any one of claims 5 to 8, characterized in that, The heat insulation film layer includes one or more of organic support material heat insulation pads and inorganic support material heat insulation pads in a laminate.

10. The battery cell according to claim 9, characterized in that, The organic support material insulation pad includes one or more of porous silicone flexible insulation pads and polymer aerogel insulation pads; the inorganic support material insulation pad includes fiberglass cloth.

11. The battery cell according to any one of claims 1 to 10, characterized in that, The edge region of the protective film includes a first insulating polymer substrate and a second insulating polymer substrate stacked together.

12. The battery cell according to any one of claims 1 to 11, characterized in that, The housing includes a first wall and a second wall adjacent to the first wall, the main body area is located on the outer surface of the first wall, and the edge area is located on the outer surface of the second wall; Optionally, the housing includes a third wall adjacent to the first wall and opposite to the second wall, and the protective film includes two edge regions located on opposite sides of the main body area, the two edge regions being located on the outer surfaces of the second wall and the third wall, respectively.

13. The battery cell according to claim 12, characterized in that, The housing includes a body and an end cap. The body includes a side plate and a bottom plate. The side plate is connected to the bottom plate. The bottom plate and the side plate together form a receiving cavity with an opening at one end. The end cap is used to seal the opening. The side plate is the first wall; of the bottom plate and the end cap, one is the second wall and the other is the third wall.

14. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 13.

15. An electrical appliance, characterized in that, It includes at least one of the battery cells according to any one of claims 1 to 13 and the battery according to claim 14.

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