Battery cell and battery pack

Abstract

A battery cell and a battery pack, relating to the technical field of batteries. The battery cell comprises: a housing (100) having a first direction, the housing (100) enclosingly forming an accommodating cavity (500), a pressure relief port (104) being provided on the housing (100), and the accommodating cavity (500) being in communication with the pressure relief port (104); a cell (200) and an electrolyte, disposed in the accommodating cavity (500); an explosion-proof valve (300), connected to the housing (100) and covering the pressure relief port (104); and a protective film (400), located on a side of the explosion-proof valve (300) facing the accommodating cavity (500), the area of an orthographic projection area of the protective film (400) onto the housing (100) along the first direction being S1 square millimeters, and the area of an orthographic projection of the explosion-proof valve (300) onto the housing (100) along the first direction being S2 square millimeters, where S1>S2. The protective film (400) covers the explosion-proof valve (300) and seals the explosion-proof valve (300). The protective film (400) covers the explosion-proof valve (300) from the inner side of the housing (100), and is further sealed to prevent the electrolyte from contacting the explosion-proof valve (300), so that the explosion-proof valve (300) is not easily corroded.

Description

Single cells and battery packs

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on November 22, 2023, with application number 202323164478.1 and invention name “Single Cell and Battery Pack”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a single cell and a battery pack. Background Art

[0003] Power batteries are equipped with explosion-proof valves. When the gas pressure inside the battery reaches a certain value, the valve explodes and releases the gas. However, during battery use, the electrolyte easily comes into contact with the explosion-proof valve, causing corrosion and shortening the service life of the valve. Summary of the Invention

[0004] The embodiments of the present application provide a single cell and a battery pack, wherein the explosion-proof valve is not easily corroded.

[0005] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0006] On the one hand, a single cell battery is provided, comprising: a shell having a first direction, the shell being arranged to form a accommodating cavity, a pressure relief port being opened on the shell, the accommodating cavity and the pressure relief port being connected; a battery cell and an electrolyte being arranged in the accommodating cavity; an explosion-proof valve being connected to the shell and covering the pressure relief port; a protective film being located on a side of the explosion-proof valve facing the accommodating cavity, the orthographic projection area of ​​the protective film on the shell along the first direction being S1 square millimeters, and the orthographic projection area of ​​the explosion-proof valve on the shell along the first direction being S2 square millimeters, wherein S1>S2, the protective film covers the explosion-proof valve and seals the explosion-proof valve.

[0007] In some embodiments, the housing includes a shell and a cover plate, the shell is arranged to form the accommodating cavity, the shell has an opening connected to the accommodating cavity, the cover plate covers the opening, and the pressure relief port is arranged on the shell and / or the cover plate.

[0008] In some embodiments, the setting positions of the pressure relief port and the protective film satisfy any one of the following three methods: Method 1: the pressure relief port is provided on the shell, and the protective film is connected to the inner surface of the shell facing the accommodating cavity; Method 2: the pressure relief port is provided on the cover plate, and the protective film is connected to the inner surface of the cover plate facing the accommodating cavity; Method 3: the pressure relief ports are respectively provided on the shell and the cover plate, and an explosion-proof valve is provided corresponding to each pressure relief port, and the protective films are respectively provided on the inner surface of the shell facing the accommodating cavity and the inner surface of the cover plate facing the accommodating cavity to cover the explosion-proof valve.

[0009] In some embodiments, the shell also has a second direction intersecting with the first direction, the cover plate includes a first end cover and a second end cover, the opening includes a first opening and a second opening, the first opening and the second opening are arranged on both sides of the shell along the second direction, the first end cover covers the first opening, and the second end cover covers the second opening, the pressure relief port is arranged on the first side wall of the shell, an exhaust bracket is provided between the battery cell and the first side wall, the exhaust bracket forms a pressure relief channel connecting the accommodating cavity and the pressure relief port, the exhaust bracket and the first side wall are sealed and fitted; the protective film is sealed and connected to the side of the exhaust bracket facing the battery cell; the protective film is connected to the side of the exhaust bracket facing the battery cell.

[0010] In some embodiments, the exhaust bracket includes a frame, which supports the battery cell on one side along the first direction, and supports the first side wall on the other side opposite to the first direction. The frame is provided with a hollow area, and the hollow area forms the pressure relief channel; the periphery of the protective film is sealed with the frame.

[0011] In some embodiments, 1.1<S1 / S2<4.0, or 1.5<S1 / S2<4.0.

[0012] In some embodiments, the protective film has a thickness of 0.005 mm to 1.5 mm.

[0013] In some embodiments, the frame includes a first side located on one side of the pressure relief channel and a second side located on the other side of the pressure relief channel, the first side is provided with a first protrusion extending toward the pressure relief channel, the second side is provided with a second protrusion extending toward the pressure relief channel, and the first protrusion and the second protrusion are staggered.

[0014] In some embodiments, a sink is provided on a side of the first sidewall facing the accommodating cavity, and the protective film is disposed in the sink.

[0015] On the other hand, a battery pack is provided, comprising the above-mentioned single battery.

[0016] In the single cell and battery pack provided in the embodiments of the present application, an electrolyte is disposed within a housing cavity, and a protective film is disposed on the side of the explosion-proof valve facing the housing cavity, that is, the protective film is disposed on the side of the explosion-proof valve facing the electrolyte. The orthographic projection area of ​​the protective film in a first direction is larger than the orthographic projection area of ​​the explosion-proof valve in the first direction, that is, the protective film can completely cover the explosion-proof valve, thereby isolating the electrolyte from the explosion-proof valve, preventing electrochemical corrosion caused by contact between the explosion-proof valve and the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] FIG1 exemplarily shows a structural diagram of a single cell;

[0019] FIG2 exemplarily shows an exploded view of a single cell;

[0020] FIG3 exemplarily shows a partial exploded view of the structure of a single battery;

[0021] FIG4 exemplarily shows a partial exploded view of the structure of a single battery;

[0022] FIG5 exemplarily shows a partial structural diagram of a single cell;

[0023] FIG6 is a partial enlarged view of point I in FIG3 ;

[0024] FIG7 exemplarily shows a partial exploded view of the structure of a single battery;

[0025] FIG8 exemplarily shows a partial structural diagram of a single cell;

[0026] FIG9 exemplarily shows a structural diagram of another single cell;

[0027] FIG10 exemplarily shows an exploded view of another single battery;

[0028] FIG11 exemplarily shows a partial exploded view of another single battery;

[0029] FIG12 exemplarily shows a structural diagram of a top cover sheet;

[0030] FIG13 exemplarily shows a partial enlarged view of the top cover sheet;

[0031] FIG. 14 exemplarily shows a partial structural diagram of another single cell.

[0032] Figure markings: 101-positive pole; 102-negative pole; 103-liquid filling port; 104-pressure relief port; 105-sunk platform; 106-through hole; 100-shell; 110-shell; 110a-first opening; 110b-second opening; 111-first side wall; 120-cover plate; 121-top cover plate; 122-insulating member; 130-first end cover; 140-second end cover; 150-exhaust bracket; 151-frame; 152-pressure relief channel; 153-first side; 154-second side; 155-first protrusion; 156-second protrusion; 200-battery cell; 300-explosion-proof valve; 400-protective film; 500-accommodation chamber. Specific embodiments

[0033] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] In the embodiments of the present application, words such as "first", "second", "third", and "fourth" are used to distinguish between identical or similar items with basically the same functions and effects. This is only for the purpose of clearly describing the technical solutions of the embodiments of the present application, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0035] In the embodiments of the present application, “a plurality of” means two or more, and “at least one” means one or more, unless otherwise clearly defined.

[0036] In the embodiments of the present application, the terms "upper" and "lower" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0037] The present application provides a battery pack, which can be a power battery pack used in electric vehicles to provide power to the electric vehicle's drive motor, etc. Of course, the battery pack can also be other types of battery packs, such as those used in electric bicycles and electric motorcycles. The present application does not limit the type of battery pack or its application scenario.

[0038] The battery pack includes a housing and a single battery mounted within the housing. The housing protects the internal single batteries from impact. The housing may include a mounting cavity, in which the single battery is mounted. The housing may contain multiple single batteries or just one. When multiple single batteries are mounted within the housing, they may be connected in series or in parallel.

[0039] The battery pack may also include a thermal management component connected to the individual cells to regulate the temperature of the individual cells. For example, multiple individual cells are arranged in an array, and the arrayed multiple individual cells form multiple cell groups. Each cell group includes multiple individual cells. The multiple individual cells within a battery group are arranged sequentially along a straight line, and the multiple cell groups are arranged in intervals perpendicular to the straight line. The thermal management component is located between two adjacent cell groups, with one side of the thermal management component connected to the individual cells in one cell group and the opposite side of the thermal management component connected to the individual cells in the other cell group.

[0040] Among them, the connection between the thermal management component and the single cell refers to any combination method in which the heat generated by the single cell can be transferred to the thermal management component through heat transfer. The thermal management component can be in direct contact or physical connection with the single cell, or the thermal management component can be connected to the single cell through other heat-conducting media to achieve heat transfer.

[0041] In actual application, the box body may be provided with a charging interface for charging and a discharging interface for discharging, and the installation cavity in the box body may also be provided with modules such as a battery management system.

[0042] Figure 1 exemplarily shows a structural diagram of a single cell, and Figure 2 exemplarily shows an exploded view of a single cell. As shown in Figures 1 and 2, a single cell includes a housing 100, an explosion-proof valve 300, a battery cell 200, and an electrolyte (not shown).

[0043] The housing 100 encloses a housing cavity 500, within which the battery cells 200 and electrolyte are disposed. A pressure relief vent 104 is provided on the housing 100, communicating with the housing cavity 500. An explosion-proof valve 300 is connected to the housing 100 and covers the pressure relief vent 104. When the pressure within the housing cavity 500 exceeds a preset value, the explosion-proof valve 300 ruptures, allowing the high-temperature, high-pressure gas within the housing cavity 500 to escape from the battery cells through the pressure relief vent 104.

[0044] In actual applications, the explosion-proof valve 300 is usually made of metal. When the electrolyte comes into contact with the explosion-proof valve 300, the explosion-proof valve 300 is prone to electrochemical corrosion, resulting in weakening or damage of the explosion-proof valve 300.

[0045] In view of this, the single battery provided in the embodiment of the present application has a protective film 400 provided on the side of the explosion-proof valve 300 facing the accommodating cavity 500. The protective film 400 isolates the electrolyte and the explosion-proof valve 300, thereby preventing the explosion-proof valve 300 from contacting the electrolyte and causing electrochemical corrosion.

[0046] The single cell provided in this application is described in detail below with reference to specific embodiments.

[0047] Example 1

[0048] As shown in FIG. 1 to FIG. 8 , the single battery includes a housing 100 , an explosion-proof valve 300 , a battery core 200 , an electrolyte (not shown in the figures), and a protective film 400 .

[0049] The housing 100 encloses a housing cavity 500, within which the battery cells 200 and electrolyte are disposed. A pressure relief vent 104 is provided on the housing 100, communicating with the housing cavity 500. An explosion-proof valve 300 is connected to the housing 100 and covers the pressure relief vent 104. When the pressure within the housing cavity 500 exceeds a preset value, the explosion-proof valve 300 ruptures, allowing the high-temperature, high-pressure gas within the housing cavity 500 to be discharged from the battery cells through the pressure relief vent 104. A protective film 400 is located on the side of the explosion-proof valve 300 facing the housing cavity 500. The orthographic projection area of ​​the protective film 400 along the first direction Y on the housing 100 is S1 square millimeters, while the orthographic projection area of ​​the explosion-proof valve 300 along the first direction Y on the housing 100 is S2 square millimeters, where S1>S2. The protective film 400 covers and seals the explosion-proof valve 300.

[0050] In the embodiment of the present application, the orthographic projection area of ​​the protective film 400 and the explosion-proof valve 300 in the first direction Y is not limited, as long as the orthographic projection area of ​​the protective film 400 in the first direction Y is larger than the orthographic projection area of ​​the explosion-proof valve 300 in the first direction Y.

[0051] For example, 1.1 < S1 / S2 < 4.0. This means that the orthographic projection area of ​​the protective film 400 in the first direction Y is 10% larger than the orthographic projection area of ​​the explosion-proof valve 300 in the first direction Y. This ensures that the protective film 400 completely isolates the explosion-proof valve 300 from the electrolyte, preventing contact between the explosion-proof valve 300 and the electrolyte. Furthermore, the area of ​​S1 is smaller than 4S2 to avoid setting S1 too large, which would occupy too much space in the accommodating cavity 500 and affect the battery's energy density.

[0052] For example, 1.5 < S1 / S2 < 4.0. That is, the orthographic projection area of ​​the protective film 400 in the first direction Y is 50% larger than the orthographic projection area of ​​the explosion-proof valve 300 in the first direction Y, thereby completely isolating the explosion-proof valve 300 from the electrolyte and preventing the explosion-proof valve 300 from contacting the electrolyte.

[0053] For example, the value of S1 / S2 may be any two of the following: 1.2, 1.4, 1.6, 1.7, 1.9, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, and 3.8. Within this range, the protective film 400 completely isolates the explosion-proof valve 300 from the electrolyte, preventing contact between the explosion-proof valve 300 and the electrolyte. At the same time, it also avoids occupying too much space in the accommodating chamber 500 and affecting the energy density of the battery.

[0054] As the area of ​​the protective film 400 increases, the area of ​​the protective film 400 used to cover the connection gradually increases (for example, the area of ​​the area where the protective film 400 is used to cover the connection with the housing 100), and the better the covering and sealing effect of the protective film 400, the electrolyte can be prevented from penetrating from the edge of the sealed connection of the protective film 400 and then contacting the explosion-proof valve 300.

[0055] In actual use, the protective film 400 is destroyed before the explosion-proof valve 300. The high-temperature, high-pressure gas in the accommodating chamber 500 contacts the protective film 400, causing it to break. After the protective film 400 is broken, the high-temperature, high-pressure gas in the accommodating chamber 500 contacts the explosion-proof valve 300, causing it to break, allowing the high-temperature, high-pressure gas to be discharged through the pressure relief port 104.

[0056] In order to make the protective film 400 be destroyed before the explosion-proof valve 300 , the tensile strength of the protective film 400 is less than or equal to the tensile strength of the explosion-proof valve 300 , and / or the melting point of the protective film 400 is less than or equal to the melting point of the explosion-proof valve 300 .

[0057] Illustratively, the tensile strength of the protective film 400 is less than 0.6 MPa.

[0058] Illustratively, the melting point of the protection film 400 is 40° C. to 200° C.

[0059] The protective film 400 may be made of plastic to prevent electrochemical corrosion between the protective film 400 and the electrolyte.

[0060] Illustratively, the material of the protective film 400 is one of PET, PC, PI, and PT.

[0061] The thickness of the protective film 400 can be 0.005 mm to 1.5 mm. The thinner the protective film 400 is, the lower the tensile strength of the protective film 400 is, and the smaller the space occupied by the internal space of the single battery is, which is conducive to improving the energy density of the single battery.

[0062] The electrolyte is disposed within the accommodating chamber 500, and the protective film 400 is disposed on the side of the explosion-proof valve 300 facing the accommodating chamber 500, that is, the protective film 400 is disposed on the side of the explosion-proof valve 300 facing the electrolyte. The orthographic projection area of ​​the protective film 400 on the housing 100 in the first direction Y is larger than the orthographic projection area of ​​the explosion-proof valve 300 on the housing 100 in the first direction Y. That is, the protective film 400 can completely cover the explosion-proof valve 300, thereby isolating the explosion-proof valve 300 from the electrolyte and preventing the explosion-proof valve 300 from contacting the electrolyte and causing electrochemical corrosion.

[0063] Continuing with Figures 1 to 3 , the housing 100 includes a shell 110 and a cover plate 120 . The cover plate 120 includes a first end cap 130 and a second end cap 140 . The first end cap 130, the second end cap 140, and the shell 110 enclose a receiving cavity 500 . The shell 110 has openings communicating with the receiving cavity 500 . The openings include a first opening 110 a and a second opening 110 b . The first opening 110 a and the second opening 110 b are disposed on opposite sides of the shell 110 along the second direction X. The pressure relief vent 104 is disposed on the shell 110 . The first end cap 130 covers the first opening 110 a , and the second end cap 140 covers the second opening 110 b . In other words, the single cell has a dual-pass structure.

[0064] In actual application, the housing 110 can be made of metal material (such as aluminum), and the pressure relief port 104 can be set on the housing 110. A mature metal processing technology can be used, which makes the processing simpler.

[0065] Illustratively, the first end cover 130 is provided with a positive electrode column 101 , and the second end cover 130 is provided with a negative electrode column.

[0066] At this time, the housing 110 is in a hollow cylindrical shape as a whole. The housing 110 includes two opposite ends along the second direction X, one end of which is a first opening 110 a and the other end of which is a second opening 110 b .

[0067] For example, as shown in FIG4 , the housing 110 is generally in the shape of a rectangular cylinder and includes a first side wall 111, a second side wall 112, a third side wall 113, and a fourth side wall 114 connected in sequence. The first side wall 111 and the third side wall 113 are disposed opposite each other, and the second side wall 112 and the fourth side wall 114 are disposed opposite each other, and the second side wall 112 and the fourth side wall 114 are disposed opposite each other to the large surface of the battery cell 200.

[0068] The pressure relief vent 104 can be provided on the first sidewall 111 of the housing 110. For example, when the battery is in use, the first sidewall 111 faces the ground. When the battery is used in an electric vehicle, when the battery discharges high-temperature, high-pressure gas through the pressure relief vent 104, the gas is directed toward the ground rather than the driver's cabin, improving the safety of the electric vehicle.

[0069] As shown in Figures 4 to 7 , an exhaust bracket 150 may be provided between the battery cell 200 and the first sidewall 111. The exhaust bracket 150 forms a pressure relief channel 152 connecting the accommodating cavity 500 and the pressure relief port 104. Figure 4 shows the exhaust bracket 150 in one position during installation, and Figure 5 shows the exhaust bracket 150 in its fully installed state.

[0070] The exhaust bracket 150 can space the battery cell 200 and the first side wall 111 by a certain distance, thereby forming a pressure relief connection between the battery cell 200 and the first side wall 111 , and high-temperature and high-pressure gas can be discharged out of the single battery through the pressure relief channel 152 and the pressure relief port 104 .

[0071] The protective film 400 can be located on the side of the exhaust bracket 150 facing the battery cell 200, and the exhaust bracket 150 and the first side wall 111 are sealed and fitted together; the protective film 400 is sealed and connected to the side of the exhaust bracket 150 facing the battery cell 200, that is, the force exerted by the battery cell 200 on the exhaust bracket 150 causes the exhaust bracket 150 to squeeze the protective film 400 toward the first side wall 111, so that the connection between the protective film 400 and the first side wall 111 is tighter, and the electrolyte is not easy to pass through the connection between the protective film 400 and the first side wall 111 and contact the explosion-proof valve 300.

[0072] There are many ways to connect the protective film 400 and the first side wall 111. The edge of the protective film 400 can be connected to the first side wall 111 by hot melting, or the protective film 400 can be connected to the first side wall 111 by bonding, etc.

[0073] As shown in Figure 6, a recessed platform 105 may be provided on the side of the first sidewall 111 facing the accommodating cavity 500. The protective film 400 is disposed within the recessed platform 105, thereby facilitating the installation and positioning of the protective film 400. Furthermore, the provision of the recessed platform 105 can reduce the space occupied by the protective film 400 within the accommodating cavity 500, thereby increasing the energy density of the single battery cell.

[0074] As shown in Figures 7 and 8, the exhaust bracket 150 may include a frame 151. The frame 151 supports the battery cell 200 on one side along the first direction Y. The frame 151 is connected to the first sidewall 111 on the other side opposite to the first direction Y. The frame 151 has a hollow area, and the hollow area forms a pressure relief channel 152. Figure 7 shows a schematic diagram before the protective film 400 is connected to the frame 151, and Figure 8 shows a schematic diagram after the protective film 400 is connected to the frame 151.

[0075] The protective film 400 can also be set on the side of the exhaust bracket 150 away from the first side wall 111, and the periphery of the protective film 400 is sealed with the frame 151, and the frame 151 can be sealed with the first side wall 111, so that the protective film 400, the frame 151 and the first side wall 111 together form a closed pressure relief channel 152. Because the frame 151 is sealed with the first side wall 111 and the protective film 400 is sealed with the edge, the electrolyte cannot enter the pressure relief channel 152 under normal conditions, thereby preventing the explosion-proof valve 300 from contacting the electrolyte and causing electrochemical corrosion. When the protective film 400 is damaged by high temperature or high pressure, the electrolyte can enter the pressure relief channel 152.

[0076] Continuing with reference to Figure 7, the frame 151 includes a first side 153 located on one side of the pressure relief channel 152 and a second side 154 located on the other side opposite to the pressure relief channel 152. The first side 153 is provided with a first protrusion 155 extending toward the pressure relief channel 152, and the second side 154 is provided with a second protrusion 156 extending toward the pressure relief channel 152. The first protrusion 155 and the second protrusion 156 are staggered.

[0077] By providing the first protrusion 155 and the second protrusion 156 , the structural strength of the frame 151 is improved, and the connection area between the protective film 400 and the frame 151 can be increased, so that the sealing connection between the protective film 400 and the frame 151 is better.

[0078] As an option, the pressure relief port 104 can also be set on one or both of the first end cover 130 or the second end cover 140, and the setting position of the protective film 400 corresponds to the pressure relief port 104, and is connected to the inner surface of the first end cover 130 and / or the second end cover 140 facing the accommodating cavity 500.

[0079] Alternatively, the pressure relief port 104 may be provided on one or both of the first end cap 130 and the second end cap 140, and the housing 110 may also be provided with the pressure relief port 104. The protective film 400 is provided at a position corresponding to the pressure relief port 104 and is connected to the inner surface of the first end cap 130 and / or the second end cap 140 facing the accommodating cavity 500, as well as the inner surface of the housing 110 facing the accommodating cavity 500.

[0080] Example 2

[0081] As shown in FIG. 9 to FIG. 14 , the single battery includes a housing 100 , an explosion-proof valve 300 , a battery cell 200 , an electrolyte (not shown in the figures), and a protective film 400 .

[0082] The housing 100 is arranged to form a receiving chamber 500, and the battery cell 200 and the electrolyte are disposed in the receiving chamber 500. A pressure relief vent 104 is provided on the housing 100, and the pressure relief vent 104 is in communication with the receiving chamber 500. The explosion-proof valve 300 is connected to the housing 100 and covers the pressure relief vent 104. When the pressure in the receiving chamber 500 exceeds a preset value, the explosion-proof valve 300 is damaged, and the high-temperature and high-pressure gas in the receiving chamber 500 can be discharged from the single battery through the pressure relief vent 104. The protective film 400 is located on the side of the explosion-proof valve 300 facing the receiving chamber 500. The orthographic projection area of ​​the protective film 400 along the first direction Y on the housing 100 is S1 square millimeters, and the orthographic projection area of ​​the explosion-proof valve 300 along the first direction Y on the housing 100 is S2 square millimeters, where S1>S2. The protective film 400 covers the explosion-proof valve 300.

[0083] Among them, in the embodiment of the present application, there is no limitation on the orthographic projection area of ​​the protective film 400 and the explosion-proof valve 300 on the housing 100 in the first direction Y, as long as the orthographic projection area of ​​the protective film 400 on the housing 100 in the first direction Y is larger than the orthographic projection area of ​​the explosion-proof valve 300 in the first direction Y.

[0084] For example, 1.1 < S1 / S2 < 4.0. This means that the orthographic projection area of ​​the protective film 400 in the first direction Y is 10% larger than the orthographic projection area of ​​the explosion-proof valve 300 in the first direction Y. This ensures that the protective film 400 completely isolates the explosion-proof valve 300 from the electrolyte, preventing contact between the explosion-proof valve 300 and the electrolyte. Furthermore, the area of ​​S1 is smaller than that of S2 to avoid setting S1 too large, which would occupy too much space in the accommodating cavity 500 and affect the battery's energy density.

[0085] For example, 1.5 < S1 / S2 < 4.0. That is, the orthographic projection area of ​​the protective film 400 in the first direction Y is 50% larger than the orthographic projection area of ​​the explosion-proof valve 300 in the first direction Y, thereby completely isolating the explosion-proof valve 300 from the electrolyte and preventing the explosion-proof valve 300 from contacting the electrolyte.

[0086] For example, the value of S1 / S2 may be any two of the following: 1.2, 1.4, 1.6, 1.7, 1.9, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, and 3.8. Within this range, the protective film 400 completely isolates the explosion-proof valve 300 from the electrolyte, preventing contact between the explosion-proof valve 300 and the electrolyte. At the same time, it also avoids occupying too much space in the accommodating chamber 500 and affecting the energy density of the battery.

[0087] As the area of ​​the protective film 400 increases, the area of ​​the connection covered by the protective film 400 gradually increases (for example, the area of ​​the area of ​​the protective film 400 used to cover the sealed connection with the housing 100). The better the sealing effect of the protective film 400, the better it can prevent the electrolyte from penetrating from the edge of the sealed connection of the protective film 400 and then contacting the explosion-proof valve 300.

[0088] In actual use, the protective film 400 is destroyed before the explosion-proof valve 300. The high-temperature, high-pressure gas in the accommodating chamber 500 contacts the protective film 400, causing it to break. After the protective film 400 is broken, the high-temperature, high-pressure gas in the accommodating chamber 500 contacts the explosion-proof valve 300, causing it to break, allowing the high-temperature, high-pressure gas to be discharged through the pressure relief port 104.

[0089] In order to make the protective film 400 be destroyed before the explosion-proof valve 300 , the tensile strength of the protective film 400 is less than or equal to the tensile strength of the explosion-proof valve 300 , and / or the melting point of the protective film 400 is less than or equal to the melting point of the explosion-proof valve 300 .

[0090] Illustratively, the tensile strength of the protective film 400 is less than 0.6 MPa.

[0091] Illustratively, the melting point of the protection film 400 is 40° C. to 200° C.

[0092] The protective film 400 may be made of plastic to prevent electrochemical corrosion between the protective film 400 and the electrolyte.

[0093] Illustratively, the material of the protective film 400 is one of PET, PC, PI, and PT.

[0094] The thickness of the protective film 400 can be 0.005 mm to 1.5 mm. The thinner the protective film 400 is, the lower the tensile strength of the protective film 400 is, and the smaller the space occupied by the internal space of the single battery is, which is conducive to improving the energy density of the single battery.

[0095] The electrolyte is disposed within the accommodating chamber 500, and the protective film 400 is disposed on the side of the explosion-proof valve 300 facing the accommodating chamber 500, that is, the protective film 400 is disposed on the side of the explosion-proof valve 300 facing the electrolyte. The orthographic projection area of ​​the protective film 400 in the first direction Y is larger than the orthographic projection area of ​​the explosion-proof valve 300 in the first direction Y, that is, the protective film 400 can completely cover the explosion-proof valve 300, thereby isolating the explosion-proof valve 300 from the electrolyte and preventing the explosion-proof valve 300 from contacting the electrolyte and causing electrochemical corrosion.

[0096] The housing 100 includes a shell 110 and a cover 120 . The shell 110 is configured to form a receiving cavity 500 . The shell 110 has an opening communicating with the receiving cavity. The cover 120 covers the opening. The pressure relief port 104 is provided on the cover 120 .

[0097] Illustratively, the cover plate 120 is provided with a positive electrode column 101 and a negative electrode column 102. The cover plate 120 may also be provided with a liquid injection port 103 through which electrolyte is injected.

[0098] The protective film 400 can be connected to the inner surface of the cover plate 120 facing the accommodating cavity 500. Continuing with Figure 11, the cover plate 120 includes a top cover sheet 121 and an insulating member 122. The insulating member 122 is located on the side of the top cover sheet 121 facing the accommodating cavity 500. The protective film 400 can be connected to the side of the top cover sheet 121 facing the accommodating cavity 500 and located between the top cover sheet 121 and the insulating member 122.

[0099] Exemplarily, as shown in FIG. 11 and FIG. 12 , the top cover sheet 121 is provided with a pressure relief port 104 , and the explosion-proof valve 300 is provided at the pressure relief port 104 .

[0100] As shown in Figure 13, a recessed platform 105 can be provided on the side of the first sidewall 111 facing the accommodating cavity 500. The protective film 400 is disposed within the recessed platform 105, thereby facilitating the installation and positioning of the protective film 400. Furthermore, the provision of the recessed platform 105 can reduce the space occupied by the protective film 400 within the accommodating cavity 500, thereby increasing the energy density of the single battery cell.

[0101] Of course, as shown in FIG14 , the protective film 400 can also be connected to the insulating member 122. In this case, the insulating member 122 is provided with a through hole 106, and the protective film 400 covers the through hole 106 and is sealed to the insulating member 122. The insulating member 122 is sealed to the top cover sheet 121, thereby isolating the protective film 400 from the electrolyte and the explosion-proof valve 300.

[0102] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A single cell battery, wherein: include: The housing (100) has a first direction (Y), the housing (100) is arranged to form a receiving cavity (500), a pressure relief port (104) is provided on the housing (100), and the receiving cavity (500) and the pressure relief port (104) are in communication; The battery cell (200) and the electrolyte are arranged in the accommodating cavity (500); An explosion-proof valve (300) connected to the housing (100) and covering the pressure relief port (104); The protective film (400) is located on a side of the explosion-proof valve (300) facing the accommodating chamber (500), and the orthographic projection area of ​​the protective film (400) on the housing (100) along the first direction (Y) is S1 square millimeters, and the orthographic projection area of ​​the explosion-proof valve (300) on the housing (100) along the first direction (Y) is S2 square millimeters, wherein S1>S2, and the protective film (400) covers the explosion-proof valve (300) and seals the explosion-proof valve (300).

2. The single cell according to claim 1, wherein: The housing (100) comprises a shell (110) and a cover plate (120); the shell (110) is arranged to surround the accommodating cavity (500); the shell (110) has an opening (12) communicating with the accommodating cavity (500); the cover plate (120) covers the opening (12); and the pressure relief port (104) is arranged on the shell (110).

3. The single cell according to claim 1, wherein: The housing (100) comprises a shell (110) and a cover plate (120); the shell (110) is arranged to surround the accommodating cavity (500); the shell (110) has an opening (12) communicating with the accommodating cavity (500); the cover plate (120) covers the opening (12); and the pressure relief port (104) is arranged on the cover plate (120).

4. The single cell according to claim 1, wherein: The housing (100) comprises a shell (110) and a cover plate (120); the shell (110) is arranged to surround the accommodating cavity (500); the shell (110) has an opening (12) communicating with the accommodating cavity (500); the cover plate (120) covers the opening (12); and the pressure relief port (104) is arranged on the shell (110) and the cover plate (120). 5 . The single cell according to claim 1 , wherein 1.1<S1 / S2<4.0, or 1.5<S1 / S2<4.

0.

6. The single cell according to any one of claims 2 to 4, wherein: The arrangement positions of the pressure relief port (104) and the protective film (400) satisfy any one of the following three methods: Mode 1: The pressure relief port (104) is disposed on the housing (110), and the protective film (400) is connected to the inner surface of the housing (110) facing the accommodating cavity (500); Mode 2: The pressure relief port (104) is arranged on the cover plate (120), and the protective film (400) is connected to the inner surface of the cover plate (120) facing the accommodating cavity (500); Method three: The pressure relief port (104) is respectively provided on the shell (110) and the cover plate (120), and an explosion-proof valve (300) is correspondingly provided for each pressure relief port (104); and the protective film (400) is respectively provided on the inner surface of the shell (110) facing the accommodating chamber (500) and the inner surface of the cover plate (120) facing the accommodating chamber (500) to cover the explosion-proof valve (300).

7. The single cell according to claim 6, wherein: 1.1<S1 / S2<4.0, or 1.5<S1 / S2<4.

0.

8. The single cell according to any one of claims 2 to 4, wherein: The housing (100) further has a second direction (X) intersecting the first direction (Y); the cover plate (120) comprises a first end cover (130) and a second end cover (140); the opening (12) comprises a first opening (110a) and a second opening (110b); the first opening (110a) and the second opening (110b) are arranged on both sides of the housing (110) along the second direction (X); the first end cover (130) covers the first opening (110a); and the second end cover (140) covers the second opening (110b); The pressure relief port (104) is arranged on a first side wall (111) of the housing (110); an exhaust bracket (150) is arranged between the battery cell (200) and the first side wall (111); the exhaust bracket (150) forms a pressure relief channel (152) connecting the accommodating cavity (500) and the pressure relief port (104); the exhaust bracket (150) and the first side wall (111) are arranged in a sealing manner; The protective film (400) is sealingly connected to a side of the exhaust bracket (150) facing the battery core (200).

9. The single cell according to claim 8, wherein: 1.1<S1 / S2<4.0, or 1.5<S1 / S2<4.

0.

10. The single cell according to claim 8, wherein: The exhaust bracket (150) comprises a frame (151), the frame (151) supports the battery cell (200) on one side along the first direction (Y), the frame (151) is connected to the first side wall (111) on the other side opposite to the first direction (Y), and the frame (151) is provided with a hollow area, and the hollow area forms the pressure relief channel (152); The periphery of the protective film (400) is covered and connected to the frame (151).

11. The single cell according to claim 10, wherein: 1.1<S1 / S2<4.0, or 1.5<S1 / S2<4.

0.

12. The single cell according to claim 1, wherein: The thickness of the protective film (400) is 0.005 mm to 1.5 mm.

13. The single cell according to claim 10, wherein: The frame (151) comprises a first edge (153) located on one side of the pressure relief channel (152) and a second edge (154) located on the other side of the pressure relief channel (152), the first edge (153) being provided with a first protrusion (155) extending toward the pressure relief channel (152), the second edge (154) being provided with a second protrusion (156) extending toward the pressure relief channel (152), and the first protrusion (155) and the second protrusion (156) being arranged alternately.

14. The single cell according to claim 8, wherein: A sink (105) is provided on a side of the first side wall (111) facing the accommodating cavity (500), and the protective film (400) is arranged in the sink (105).

15. A battery pack, wherein: The invention comprises a single cell according to any one of claims 1 to 14.

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