Battery, battery pack and energy storage system

Abstract

The utility model provides a battery, a battery pack and an energy storage system, and belongs to the technical field of batteries. The battery comprises a battery cell top cover and a battery cell, and the battery cell top cover covers the top of the battery cell; the battery cell top cover comprises a top cover sheet, an anti-explosion valve and at least two protective films, the top cover sheet is provided with a through hole, and each protective film is provided with an air hole; the explosion-proof valve is located in the through hole, the at least two protective films sequentially cover the explosion-proof valve and are opposite to the battery cell, a gap is formed between the protective film closest to the explosion-proof valve and the explosion-proof valve, a gap is formed between every two adjacent protective films, and the positions of the air holes of every two adjacent protective films are relatively staggered. According to the battery, electrolyte entering the anti-explosion valve can be reduced, and even the electrolyte can be prevented from entering the anti-explosion valve, so that the protection effect on the anti-explosion valve is improved, and the air tightness in the battery cell is ensured.

Description

Technical Field

[0001] The present disclosure relates to the field of battery technology, and in particular to a battery, a battery pack and an energy storage system. Background Art

[0002] If batteries, such as lithium-ion batteries, are used improperly in applications, such as overcharging, short-circuiting, or using in a high-temperature environment, a large amount of gas will be generated inside the battery cell, increasing its internal pressure, and the battery is prone to explosion. In order to prevent the battery from exploding due to improper use, an explosion-proof valve is usually arranged on the top cover of the battery cell. When the internal pressure of the battery cell increases, the explosion-proof valve is pushed open to achieve the purpose of pressure relief.

[0003] In order to prevent foreign objects from damaging the explosion-proof valve, a protective film is usually placed above the explosion-proof valve to protect it. After the protective film is placed, a closed space is formed between the protective film and the explosion-proof valve. In addition, since the battery preparation process involves high-temperature treatment, in order to avoid the protective film wrinkling and deforming due to excessive air pressure in the closed space between the protective film and the explosion-proof valve during high-temperature treatment, and thus causing the protective film to fail, ventilation holes are generally opened on the protective film.

[0004] However, once air holes are opened on the protective film, during the battery preparation process, such as when pouring electrolyte into the battery cell, the electrolyte will splash from the injection hole onto the protective film, and the electrolyte will overflow from the injection hole and flow onto the protective film. Once a large amount of electrolyte accumulates on the protective film, the electrolyte will flow along the air holes to the explosion-proof valve, and corrode the explosion-proof valve. After the explosion-proof valve is corroded, the air tightness inside the battery cell will be reduced. Utility Model Content

[0005] The present disclosure provides a battery, a battery pack and an energy storage system. The battery can reduce the amount of electrolyte entering the explosion-proof valve, and can even prevent the electrolyte from entering the explosion-proof valve, thereby enhancing the protection of the explosion-proof valve and ensuring the airtightness inside the battery cell.

[0006] In a first aspect, a battery is provided, the battery comprising a battery cell top cover and a battery cell, the battery cell top cover covering the top of the battery cell;

[0007] The battery cell top cover comprises a top cover sheet, an explosion-proof valve and at least two protective films, the top cover sheet has a through hole, and each protective film has a vent hole;

[0008] The explosion-proof valve is located in the through hole, and the at least two protective films sequentially cover the explosion-proof valve on the side facing away from the battery core. There is a gap between the protective film closest to the explosion-proof valve and the explosion-proof valve, and there is a gap between two adjacent protective films. The air holes of the two adjacent protective films are relatively staggered.

[0009] In the scheme shown in the present disclosure, there are multiple protective films, which are sequentially covered on the top of the explosion-proof valve, and the air holes of any two adjacent protective films are staggered. The flow path of the electrolyte from the air holes of the outermost protective film to the air holes of the innermost protective film can be enlarged. Once the flow path is relatively long, the electrolyte will evaporate and remain on the protective film during the flow, and gradually decrease, so that a small amount of electrolyte falls on the explosion-proof valve, or no electrolyte falls on the explosion-proof valve, thereby enhancing the protection of the explosion-proof valve and ensuring good air tightness inside the battery cell.

[0010] In a possible implementation, the first vent hole of the first protective film and the second vent hole of the second protective film of the two adjacent protective films are both located on the straight line L where the maximum aperture connection line of the through hole is located;

[0011] The first air hole is located between the center point of the first protective film and a first position A, and is close to the first position A; the second air hole is located between the center point of the second protective film and a second position B, and is close to the second position B;

[0012] Among them, the first position A is the intersection of the straight line L where the maximum aperture line is located and the first protective film, the second position B is the intersection of the straight line L where the maximum aperture line is located and the second protective film, and the first position A and the second position B are located on opposite sides of the center line of the through hole.

[0013] In the solution shown in the present disclosure, the first vent hole is as close to the first position A as possible, and the second vent hole is as close to the second position B as possible, thereby increasing the center distance between the first vent hole and the second vent hole on the straight line L. The flow path of the electrolyte from the vent hole of the outermost protective film to the vent hole of the innermost protective film is further increased. The longer the flow path, the more electrolyte is lost during the flow, and the less electrolyte enters the explosion-proof valve, or even no electrolyte flows into the explosion-proof valve, further improving the protection of the explosion-proof valve.

[0014] In a possible implementation manner, the protective film farthest from the explosion-proof valve is higher than the outer surface of the top cover sheet.

[0015] In the scheme disclosed in the present invention, the outermost protective film is higher than the outer surface of the top cover sheet, which can prevent the electrolyte overflowing from the injection hole from flowing into the outermost protective film, thereby reducing the electrolyte entering the outermost protective film. Once the electrolyte accumulated on the outermost protective film is relatively small, then the electrolyte flowing to the innermost protective film is even less, and the electrolyte falling on the explosion-proof valve is even less, further reducing or even preventing the corrosion of the explosion-proof valve by the electrolyte.

[0016] In a possible implementation manner, the protective film closest to the explosion-proof valve is higher than the outer surface of the top cover sheet.

[0017] In the scheme shown in the present disclosure, the innermost protective film is higher than the outer surface of the top cover sheet, which means that all protective films are higher than the outer surface of the top cover sheet. Then, the outermost protective film is relatively high from the outer surface of the top cover sheet. On the one hand, it further prevents the electrolyte overflowing from the injection hole from flowing onto the outermost protective film. On the other hand, when the electrolyte is injected into the injection hole, it is not easy for the electrolyte to splash onto the outermost protective film, or the amount of electrolyte splashing onto the outermost protective film is reduced. It can be seen that this scheme can reduce the electrolyte accumulated on the outermost protective film, thereby reducing the electrolyte flowing into the explosion-proof valve.

[0018] In a possible implementation, the battery cell top cover further includes at least one circle of bosses, wherein the bosses are located on the outer surface of the top cover sheet and surround the through holes;

[0019] A protective film higher than the outer surface of the top cover sheet is fixed on a circle of bosses.

[0020] In the scheme shown in the present disclosure, the number of bosses is equal to the number of protective films higher than the top cover sheet. For example, if the number of protective films higher than the top cover sheet is one, then the number of bosses is one circle. For another example, if the number of protective films higher than the outer surface of the top cover sheet is multiple, then the number of bosses is multiple circles. These bosses are arranged in sequence along the radial direction of the through hole, and the height gradually increases from close to the through hole to away from the through hole.

[0021] In a possible implementation manner, a width of the boss along a radial direction of the through hole is greater than or equal to 0.5 mm and less than or equal to 1 mm.

[0022] In the solution shown in the present disclosure, the width of the boss is between 0.5 mm and 1 mm, which can increase the fixing area between the protective film and the boss, so that the protective film is more firmly fixed on the boss and prevent the protective film from falling off.

[0023] In a possible implementation manner, the protective film closest to the explosion-proof valve is fixed to the outer surface of the top cover sheet.

[0024] In the solution shown in the present disclosure, since the protective film is relatively thin, the protective film fixed on the outer surface of the top cover sheet is equivalent to being flush with the outer surface of the top cover sheet.

[0025] In a possible implementation, the protective film farthest from the explosion-proof valve is lower than or flush with the top of the pole on the outer surface of the top cover sheet.

[0026] In the solution shown in the present disclosure, in the battery assembly, it is generally necessary to install an insulating bracket above the top cover of the battery cell, and the aluminum strip is arranged on the insulating bracket and connected to the pole such as welding. If the outermost protective film is higher than the top of the pole, then the insulating bracket will be raised or lifted by the outermost protective film, increasing the difficulty of battery assembly. Therefore, the outermost protective film is lower than or flush with the top of the pole, which can reduce the difficulty of battery assembly and improve the battery assembly efficiency.

[0027] In a second aspect, a battery pack is provided, comprising a plurality of batteries as described in the first aspect, wherein the plurality of batteries are connected in series or in parallel.

[0028] In a third aspect, an energy storage system is provided, comprising a power converter and at least one battery pack as described in the second aspect; the power converter is used to convert the voltage output by the battery pack into power and output it to a power grid or a load, and / or to convert the voltage output by an external power supply into power and output it to the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of a battery provided by an exemplary embodiment of the present disclosure;

[0030] Figure 2 is a schematic top view of two adjacent protective films provided by an exemplary embodiment of the present disclosure;

[0031] Figure 3 It is a schematic diagram of the structure of a battery cell top cover provided by an exemplary embodiment of the present disclosure, in which the innermost protective film is fixed to the outer surface of the top cover sheet, and the outermost protective film is fixed to the boss;

[0032] Figure 4 It is a schematic diagram of the structure of a battery cell top cover provided by an exemplary embodiment of the present disclosure, in which the innermost protective film is fixed to a sink, and the outermost protective film is fixed to the outer surface of a top cover sheet;

[0033] Figure 5 It is a schematic structural diagram of a cell top cover with two circles of bosses located on the outer surface of a top cover sheet provided by an exemplary embodiment of the present disclosure;

[0034] Figure 6 It is a schematic structural diagram of a battery cell top cover having a recessed groove on the outer surface of a top cover sheet provided by an exemplary embodiment of the present disclosure;

[0035] Figure 7 yes Figure 1 A schematic diagram of the partial structure of the battery cell top cover located on the left side of the through hole;

[0036] Figure 8 It is a structural schematic diagram of a battery module formed by multiple batteries connected in series or in parallel.

[0037] Description of Reference Numerals

[0038] 1. Top cover; 11. Through hole; 12. Liquid injection hole; 13. Sink.

[0039] 2. Explosion-proof valve.

[0040] 3. Protective film; 3A. First protective film; 3B. Second protective film; 3C. Innermost protective film; 3D. Outermost protective film.

[0041] 31, ventilation holes; 31A, first ventilation holes; 31B, second ventilation holes; 31C, innermost ventilation holes; 31D, outermost ventilation holes.

[0042] 4. Pole.

[0043] 5. Boss; 5A, innermost boss; 5B, outermost boss.

[0044] 10. Battery cell top cover; 20. Battery cell. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0046] This embodiment provides a battery, which can be any type of battery with an explosion-proof valve, such as a lithium-ion battery. Figure 1 The diagram shows the structure of the battery. Figure 1 As shown, the battery includes a cell top cover 10 and a cell 20 , wherein the number of the cell 20 is one or more, the cell top cover 10 and the cell 20 correspond one to one, and each cell top cover 10 covers the top of a cell 20 .

[0047] The structural features of the battery cell top cover are introduced below.

[0048] Continue to refer Figure 1 As shown, the battery cell top cover comprises a top cover sheet 1, and the top cover sheet 1 has a liquid injection hole 12 running through the thickness direction, and the liquid injection hole 12 is used for injecting electrolyte into the battery cell. Figure 1 As shown, the battery cell top cover also includes two poles 4, one as a positive pole and the other as a negative pole.

[0049] Because the battery has explosion-proof function, please refer to Figure 1 As shown, the battery cell top cover also includes an explosion-proof valve 2, and the top cover sheet 1 also has a through hole 11 that runs through the thickness direction, and the explosion-proof valve 2 is installed in the through hole 11. For example, referring to Figure 1As shown, the explosion-proof valve 2 is installed at the bottom end of the through hole 11 close to the battery cell 20. Of course, the explosion-proof valve 2 can also be installed in the middle position of the through hole 11, or the explosion-proof valve 2 can also be installed at the top of the through hole 11 away from the battery cell 20. Among them, this embodiment does not limit the specific position of the explosion-proof valve 2 in the through hole 11, and the explosion-proof valve 2 can be located at the bottom end of the through hole 11 for example in the drawings.

[0050] refer to Figure 1 As shown, the injection hole 12 is close to the through hole 11 , so when the electrolyte is injected into the injection hole 12 , the electrolyte will splash from the injection hole 12 into the through hole 11 , and corrode the explosion-proof valve 2 .

[0051] So, continue to refer to Figure 1 As shown, the battery cell top cover also includes a protective film 3, wherein the material of the protective film 3 can be polypropylene (PP). The number of protective films 3 is two or more (two are used as an example in the figure), and these protective films 3 are sequentially covered on the top of the explosion-proof valve 2 facing away from the battery cell to prevent electrolyte and foreign matter from falling on the explosion-proof valve 2.

[0052] For ease of introduction, refer to Figure 1 As shown in the figure, the protective film 3 located at the innermost layer is referred to as the innermost protective film 3C, and the protective film 3 located at the outermost layer is referred to as the outermost protective film 3D.

[0053] In one example, in order to prevent the protective film 3 from bulging and falling off due to the increase of the internal pressure between the protective film 3 and the explosion-proof valve 2 when the ambient temperature or air pressure changes during the preparation of the battery, the reference Figure 1 As shown, each protective film 3 has air pores 31, wherein, for the convenience of introduction, the air pores 31 on the outermost protective film 3D are recorded as outermost air pores 31D, and the air pores 31 on the innermost protective film 3C are recorded as innermost air pores 31C.

[0054] The shape of the air holes 31 can be circular, elliptical, quadrilateral, or long linear.

[0055] Because multiple protective films 3 are sequentially covered on the explosion-proof valve 2, in order to avoid close contact, the air vent 31 becomes ineffective. Figure 1 As shown, the innermost protective film 3C closest to the explosion-proof valve 2 has a gap with the explosion-proof valve 2, and there is also a gap between two adjacent protective films 3.

[0056] Continue to refer Figure 1As shown, the positions of the air holes 31 of two adjacent protective films 3 are staggered. For example, the vertical projections of the two air holes 31 in the horizontal plane where the top cover sheet 1 is located are far apart.

[0057] In this way, during the process of injecting liquid into the injection hole 12, even if the electrolyte splashes onto the outermost protective film 3D farthest from the explosion-proof valve 2, the electrolyte needs to flow from the outermost vent hole 31D on the outermost protective film 3D to the innermost vent hole 31C on the innermost protective film 3C before it can fall on the explosion-proof valve 2. Because the vent holes 31 of any two adjacent protective films 3 in the multiple protective films 3 are staggered, the flow path of the electrolyte is lengthened. The electrolyte will evaporate during the flow and will also hang on (i.e. remain on) the surface of the protective film 3, thereby reducing or even preventing the electrolyte from falling on the explosion-proof valve 2, thereby enhancing the protection of the explosion-proof valve 2 and ensuring good air tightness inside the battery cell.

[0058] As can be seen from the above, the farther the air holes 31 of two adjacent protective films 3 are from each other in the horizontal direction, the less electrolyte will fall on the explosion-proof valve 2. Figure 2 As shown, it is a top view schematic diagram of any two adjacent protective films 3, Figure 2 The protective film 3 indicated by the dotted line represents the protective film 3 located below, which is denoted as the first protective film 3A. Figure 2 The protective film 3 indicated by the solid line in the middle indicates the protective film 3 at the upper position, which is recorded as the second protective film 3B. The vent holes 31 of the first protective film 3A are recorded as first vent holes 31A, and the vent holes 31 of the second protective film 3B are recorded as second vent holes 31B.

[0059] refer to Figure 2 As shown, the first air hole 31A and the second air hole 31B are both located on the straight line L where the maximum aperture connection line of the through hole 11 is located, and the first air hole 31A is located between the center point of the first protective film 3A and the first position A, and is closer to the first position A, and the second air hole 31B is located between the center point of the second protective film 3B and the second position B, and is closer to the second position B.

[0060] Among them, Figure 2 The first position A is the intersection of the straight line L where the maximum aperture line is located and the first protective film 3A, and the second position B is the intersection of the straight line L where the maximum aperture line is located and the second protective film 3B, and the first position A and the second position B are located on the opposite sides of the center line of the through hole 11.

[0061] The first position A and the second position B are located on the opposite sides of the center line of the through hole 11, that is, on the straight line L, one of the first position A and the second position B is located on the left side of the center line of the through hole 11, and the other is located on the right side of the center line of the through hole 11. The center line of the through hole 11 is a straight line passing through the center of the through hole 11 and perpendicular to the protective film 3. It can also be said that the center line of the through hole 11 is a straight line passing through the center of the through hole 11. Figure 2 The straight line is at position O in the middle and perpendicular to the protective film 3.

[0062] In this way, the first ventilation hole 31A is as close to the first position A as possible, and the second ventilation hole 31B is as close to the second position B as possible, so that the center distance between the first ventilation hole 31A and the second ventilation hole 31B on the straight line L can be increased.

[0063] For example, the shortest distance between the first vent hole 31A and the first position A is greater than or equal to 1 mm and less than or equal to 2 mm, and the shortest distance between the second vent hole 31B and the second position B is greater than or equal to 1 mm and less than or equal to 2 mm.

[0064] In a possible application mode, the protective film 3 can be first fixed on the explosion-proof valve 2, and then the air holes 31 can be opened on the protective film 3. For example, the innermost protective film 3C can be first fixed on the explosion-proof valve 2, and then the air holes 31 can be opened on the innermost protective film 3C. Then, another protective film 3 can be fixed on the innermost protective film 3C, and then the air holes 31 can be opened on the protective film 3. The horizontal spacing between the two air holes 31 can be as large as possible. The remaining protective films 3 can be fixed in this way.

[0065] It should be noted that the maximum aperture line of the through hole 11 described above is related to the specific shape of the through hole 11. For example, if the cross-sectional shape of the through hole 11 is circular, then the maximum aperture line is the diameter line. For another example, if the cross-sectional shape of the through hole 11 is elliptical, then the maximum aperture line is the major axis line. For another example, if the cross-sectional shape of the through hole 11 is rectangular or square, then the maximum aperture line is the diagonal line.

[0066] Next, the positional relationship of the plurality of protective films 3 will be described.

[0067] First, the outermost protective film 3 is introduced, its position relative to the outer surface of the top cover sheet 1 facing away from the battery cell, and its position relative to the top of the pole 4.

[0068] In one example, reference Figure 1 As shown, the protective film 3 farthest from the explosion-proof valve 2 , that is, the outermost protective film 3D, may be higher than the outer surface of the top cover sheet 1 .

[0069] In another example, the outermost protective film 3D may be flush with the outer surface of the top cover sheet 1. In another example, the outermost protective film 3D may also be lower than the outer surface of the top cover sheet 1.

[0070] The outermost protective film 3D is higher than the outer surface of the top cover sheet 1, which can prevent the electrolyte overflowing from the injection hole 12 from flowing into the outermost protective film 3D, thereby reducing the electrolyte entering the outermost protective film 3D. Once the electrolyte accumulated on the outermost protective film 3D is relatively small, then, based on the above, less electrolyte flows to the innermost protective film 3C, and less electrolyte falls on the explosion-proof valve 2, further reducing or even preventing the corrosion of the explosion-proof valve 2 by the electrolyte.

[0071] In one example, reference Figure 1 As shown, the outermost protective film 3D is lower than or flush with the top of the pole 4 on the outer surface of the top cover sheet 1. In battery assembly, it is generally necessary to install an insulating bracket above the top cover of the battery cell (refer to Figure 8 As shown in FIG. 1 , the aluminum strip is arranged on the insulating support and connected to the pole 4 (such as welding). If the outermost protective film 3D is higher than the top of the pole 4, the insulating support will be raised or lifted by the outermost protective film 3D, which increases the difficulty of assembling the battery. Therefore, the outermost protective film 3D is lower than or flush with the top of the pole 4, which can reduce the difficulty of assembling the battery and improve the assembly efficiency of the battery.

[0072] Next, the position of the other layer of the protective film 3 relative to the outer surface of the top cover sheet 1 facing away from the battery cell is introduced.

[0073] In one example, the protective film 3 closest to the explosion-proof valve 2, that is, the innermost protective film 3C, can be higher than the outer surface of the top cover sheet 1. Figure 1 As shown, the outermost protective film 3D and the innermost protective film 3C are both higher than the outer surface of the top cover sheet 1 .

[0074] In the solution where both the innermost protective film 3C and the outermost protective film 3D are higher than the outer surface of the top cover sheet 1 , the intermediate protective film 3 between the innermost layer and the outermost layer is also higher than the outer surface of the top cover sheet 1 .

[0075] In another example, the innermost protective film 3C may also be flush with the outer surface of the top cover sheet 1. Figure 3 As shown, the innermost protective film 3C is flush with the outer surface of the top cover sheet 1, and the outermost protective film 3D is higher than the outer surface of the top cover sheet 1. Then, the protective film 3 of the intermediate layer between the innermost layer and the outermost layer is also higher than the outer surface of the top cover sheet 1.

[0076] In this case, all the protective films 3 are higher than the outer surface of the top cover sheet 1, or the innermost protective film 3C is flush with the outer surface of the top cover sheet 1, while the other layers of the protective films 3 are all higher than the outer surface of the top cover sheet 1, indicating that the outermost protective film 3D is relatively high relative to the outer surface of the top cover sheet 1. Then, when the liquid is injected into the injection hole 12, the electrolyte is not easy to splash onto the outermost protective film 3, thereby reducing the electrolyte accumulated on the outermost protective film 3D.

[0077] In one example, if Figure 4 As shown, the innermost protective film 3C may also be lower than the outer surface of the top cover sheet 1. In the solution where the innermost protective film 3C is lower than the outer surface of the top cover sheet 1, the protective films 3 of other layers located above the innermost protective film 3C, for example, the outermost protective film 3D, or the intermediate protective film 3, may be lower than the outer surface of the top cover sheet 1, may be flush with the outer surface of the top cover sheet 1, or may be higher than the outer surface of the top cover sheet 1. For example, referring to Figure 4 As shown, the outermost protective film 3D is flush with the outer surface of the top cover sheet 1 , and the innermost protective film 3C is lower than the outer surface of the top cover sheet 1 .

[0078] The above is the positional relationship of each layer of the protective film 3 relative to the outer surface of the top cover sheet 1. The structure for realizing the above positional relationship will be introduced below.

[0079] In one example, the protective film 3 which is higher than the outer surface of the top cover sheet 1 can be fixed on a boss which protrudes from the outer surface of the top cover sheet 1 , so as to be higher than the outer surface of the top cover sheet 1 .

[0080] Correspondingly, such as Figure 5 As shown, the cell top cover also includes a boss 5, which is located on the outer surface of the top cover sheet 1 and surrounds the through hole 11. Figure 1 As shown, the protective film 3 higher than the outer surface of the top cover sheet 1 is fixed on the surface of a circle of bosses 5 .

[0081] The number of circles of the boss 5 is equal to the number of the protective films 3 that are higher than the outer surface of the top cover sheet 1 .

[0082] For example, Figure 1 As shown, the number of protective films 3 higher than the outer surface of the top cover sheet 1 is two, then, if Figure 5 As shown, the number of bosses 5 is two. Figure 3 As shown, the number of the protective film 3 higher than the outer surface of the top cover sheet 1 is one, and thus the number of the bosses 5 is one circle.

[0083] For the solution where the number of protective films 3 above the outer surface of the top cover sheet 1 is two or more, the number of bosses 5 is two or more circles, refer to Figure 5As shown, these bosses 5 are arranged along the radial direction of the through hole 11, and the height of the boss 5 close to the through hole 11 is lower than the height of the boss 5 away from the through hole 11. A protective film 3 is fixed on each circle of bosses 5, so that these protective films 3 are higher than the outer surface of the top cover sheet 1.

[0084] In one example, in a solution where the number of bosses 5 is multiple, two adjacent bosses 5 can be fixed together (refer to Figure 5 As shown), there may also be a gap, which is not limited in this embodiment.

[0085] In one example, reference Figure 5 As shown, the inner wall of the boss 5 closest to the through hole 11 can be coplanar with the inner wall of the through hole 11. Of course, there can also be a horizontal spacing between the inner wall of the boss 5 closest to the through hole 11 and the inner wall of the through hole 11, such as the inner diameter of the boss 5 closest to the through hole 11 is larger than the inner diameter of the through hole 11, or the inner diameter of the boss 5 closest to the through hole 11 is smaller than the inner diameter of the through hole 11.

[0086] In one example, reference Figure 3 and Figure 4 As shown, the protective film 3 flush with the outer surface of the top cover sheet can be fixed on the outer surface of the top cover sheet 1 (the thickness of the protective film 3 is relatively thin and can be approximately regarded as flush with the outer surface of the top cover sheet 1).

[0087] In one example, the protective film 3 which is lower than the outer surface of the top cover sheet 1 can be fixed on the sink at the top end of the through hole 11 to be lower than the outer surface of the top cover sheet 1 .

[0088] Correspondingly, such as Figure 6 As shown, the outer surface of the top cover sheet 1 has a recess 13 around the through hole 11, referring to Figure 4 As shown, the protective film 3 below the outer surface of the top cover sheet 1 is fixed to the bottom of a circle of sink grooves 13 .

[0089] The number of circles of the sink grooves 13 is equal to the number of the protective films 3 below the outer surface of the top cover sheet 1 .

[0090] For example, Figure 4 As shown, the number of the protective film 3 below the outer surface of the top cover sheet 1 is one, then, Figure 6 As shown, the number of the sinks 13 is one circle.

[0091] For the solution where the number of protective films 3 below the outer surface of the top cover sheet 1 is two or more, the number of sinks 13 is two or more circles, refer to Figure 6As shown, these grooves 13 are arranged along the radial direction of the through hole 11, and the groove depth of the groove 13 close to the through hole 11 is greater than the groove depth of the groove 13 away from the through hole 11. A protective film 3 is fixed on each circle of grooves 13, so that these protective films 3 are all lower than the outer surface of the top cover sheet 1.

[0092] In another example, the protective film 3 below the outer surface of the top cover sheet 1 can also be fixed on the inner wall of the through hole 11. For example, the inner wall of the through hole 11 has a groove, the notch of the groove faces the through hole 11, and the protective film 3 is fixed on the groove wall of the groove. For another example, the protective film 3 below the outer surface of the top cover sheet 1 has an upward or downward flange, and the flange of the protective film 3 is directly fixed on the inner wall of the through hole 11.

[0093] In one example, in the solution where the protective film 3 is fixed to the boss 5, in order for the boss 5 to be able to support the protective film 3, the width of the boss 5 along the radial direction of the through hole 11 is greater than or equal to 0.5 mm and less than or equal to 1 mm. In this way, the fixing area between the protective film 3 and the surface of the boss 5 is relatively large, and the fixing of the protective film 3 and the boss 5 is relatively firm, so that the boss 5 can support the protective film 3.

[0094] In one example, in a solution where the number of bosses 5 is multiple circles, the multiple bosses 5 can be arranged with equal widths or with unequal widths, which is not limited in this embodiment.

[0095] For example, Figure 7 As shown, it is a schematic diagram of the structure of the battery cell top cover on one side of the through hole 11, Figure 7 The width of the outermost circle boss 5B is w2, and the width of the innermost circle boss 5A is w1. w1 and w2 can be equal or different, but both are greater than or equal to 0.5 mm and less than or equal to 1 mm. Among them, the outermost circle boss 5B is the outermost boss from the through hole 11, and the innermost circle boss 5A is the boss closest to the through hole 11.

[0096] Likewise, reference Figure 3 As shown, if the protective film 3 fixed on the outer surface of the top cover sheet 1 is the innermost protective film, or a protective film of a middle layer, then the horizontal distance between the inner wall of the boss 5 closest to the through hole 11 and the inner wall of the through hole 11 is greater than or equal to 0.5 mm and less than or equal to 1 mm. In this way, the fixing area between the protective film 3 fixed on the outer surface of the top cover sheet 1 and the top cover sheet 1 is relatively large, the fixing relationship is more firm, and the protective film is not easy to fall off.

[0097] Similarly, in the solution where the protective film 3 is fixed to the groove 13, the width of the groove 13 along the radial direction of the through hole 11 is greater than or equal to 0.5 mm and less than or equal to 1 mm, so that the fixing area between the protective film 3 and the bottom of the groove 13 is relatively large, the fixing of the protective film 3 to the groove 13 is relatively firm, and the protective film 3 is not easy to fall off.

[0098] In the present embodiment, there are multiple protective films 3, which are sequentially covered on the top of the explosion-proof valve 2, and the air holes 31 of any two adjacent protective films 3 are staggered, which can enlarge the flow path of the electrolyte from the air holes 31 of the outermost protective film 3 to the air holes 31 of the innermost protective film 3. Once the flow path is relatively long, the electrolyte will evaporate and remain on the protective film 3 during the flow, and gradually decrease, so that a small amount of electrolyte falls on the explosion-proof valve 2, or no electrolyte falls on the explosion-proof valve 2, thereby enhancing the protection of the explosion-proof valve 2 and ensuring the good air tightness inside the battery cell.

[0099] In addition, at least one of the multiple protective films 3 can be higher than the outer surface of the top cover sheet 1, which can prevent the electrolyte overflowing from the injection hole 12 from flowing into the outermost protective film 3, thereby reducing the electrolyte entering the outermost protective film 3. Once the electrolyte accumulated on the outermost protective film 3 is relatively small, then the electrolyte flowing to the innermost protective film 3 is even less, and the electrolyte falling on the explosion-proof valve 2 is even less, or even no electrolyte falls on the explosion-proof valve 2, further reducing or even avoiding the corrosion of the explosion-proof valve 2 by the electrolyte.

[0100] This embodiment also provides a battery pack, which is an integral unit assembled from a plurality of the above-mentioned batteries, for storing and providing electric energy, wherein the plurality of batteries included in the battery pack are connected in series or in parallel. Figure 8 As shown, multiple batteries described above are connected in series or in parallel to form a battery module, and the battery modules are assembled to form a battery pack. The connection between multiple batteries can be through aluminum bars, which can be arranged as follows Figure 8 The insulating bracket is shown and connected to the battery terminal.

[0101] In one example, the battery pack includes not only the battery described above, but also a battery management system (BMS), a heat dissipation system, an electrical interface, and a housing.

[0102] Among them, the battery management system is used to monitor the status of each battery, control the charging and discharging process of each battery, and protect and balance each battery to ensure the safety and performance stability of the battery pack.

[0103] Among them, the heat dissipation system is used to control the temperature, prevent the battery from overheating, and maintain each battery within a relatively suitable temperature range.

[0104] The electrical interface is used for external connection to obtain electrical energy or transmit electrical energy to the outside.

[0105] Among them, the outer shell is used to protect internal components, such as batteries and battery management systems, and provide physical support and isolation for internal components, while ensuring the safety and reliability of the battery pack.

[0106] This embodiment also provides an energy storage system, which includes a power converter and at least one of the above-mentioned battery packs. The power converter is used to convert the voltage output by the battery pack into power and output it to the power grid or load, and / or to convert the voltage output by the external power supply into power and output it to the battery pack.

Claims

1. A battery, characterized in that: The battery comprises a cell top cover and a cell, wherein the cell top cover covers the top of the cell; The battery cell top cover comprises a top cover sheet (1), an explosion-proof valve (2) and at least two protective films (3); the top cover sheet (1) has a through hole (11), and each protective film (3) has a vent hole (31); The explosion-proof valve (2) is located in the through hole (11), the at least two protective films (3) sequentially cover the explosion-proof valve (2) on the side facing away from the battery core, a gap is provided between the explosion-proof valve (2) and the protective film (3) closest to the explosion-proof valve (2), a gap is provided between two adjacent protective films (3), and the air holes (31) of the two adjacent protective films (3) are relatively staggered in position.

2. The battery according to claim 1, characterized in that The first vent hole (31A) of the first protective film (3A) and the second vent hole (31B) of the second protective film (3B) of the two adjacent protective films (3) are both located on the straight line L where the maximum aperture connection line of the through hole (11) is located; The first vent hole (31A) is located between the center point of the first protective film (3A) and a first position A, and is close to the first position A; the second vent hole (31B) is located between the center point of the second protective film (3B) and a second position B, and is close to the second position B; The first position A is the intersection of the straight line L where the maximum aperture line is located and the first protective film (3A), and the second position B is the intersection of the straight line L where the maximum aperture line is located and the second protective film (3B), and the first position A and the second position B are located on different sides of the center line of the through hole (11).

3. The battery according to claim 1, characterized in that The protective film (3) farthest from the explosion-proof valve (2) is higher than the outer surface of the top cover sheet (1).

4. The battery according to claim 1, characterized in that The protective film (3) closest to the explosion-proof valve (2) is higher than the outer surface of the top cover sheet (1).

5. The battery according to claim 3 or 4, characterized in that: The battery cell top cover further comprises at least one circle of bosses (5), wherein the bosses (5) are located on the outer surface of the top cover sheet (1) and surround the through hole (11); A protective film (3) higher than the outer surface of the top cover sheet (1) is fixed on a circle of bosses (5).

6. The battery according to claim 5, characterized in that The width of the boss (5) along the radial direction of the through hole (11) is greater than or equal to 0.5 millimeters and less than or equal to 1 millimeter.

7. The battery according to claim 1, characterized in that The protective film (3) closest to the explosion-proof valve (2) is fixed on the outer surface of the top cover sheet (1).

8. The battery according to claim 1, characterized in that The protective film (3) farthest from the explosion-proof valve (2) is lower than or flush with the top of the pole (4) on the outer surface of the top cover sheet (1).

9. A battery pack, characterized in that: The battery pack comprises a plurality of batteries as described in any one of claims 1 to 8, and the plurality of batteries are connected in series or in parallel.

10. An energy storage system, characterized in that: The energy storage system includes a power converter and at least one battery pack as described in claim 9; the power converter is used to convert the voltage output by the battery pack into power and output it to a power grid or a load, and / or to convert the voltage output by an external power supply into power and output it to the battery pack.

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