Battery cell, battery pack and energy storage system

Abstract

The utility model provides a battery cell, a battery pack and an energy storage system. The battery cover plate specifically comprises a cover plate, a pole and an insulating ring. The cover plate is provided with a mounting hole and comprises an upper plastic part, a top cover piece and a lower plastic part. And the mounting hole penetrates through the upper plastic part, the top cover sheet and the lower plastic part. And the pole is mounted in the mounting hole. The sealing ring is arranged between the peripheral surface of the pole and the inner wall of the mounting hole; and the upper plastic part, the top cover piece and the lower plastic part are respectively propped against the sealing ring. And a gap is formed between the peripheral surface of the sealing ring and the inner wall of the lower plastic part. At least one opening of the gap is covered with an insulator. In the battery cell provided by the invention, the insulating part covers the opening of the gap, the phenomenon that the electrolyte is electrically connected with the pole and the top cover plate can be improved, the sealing insulativity between the sealing ring and the cover plate is improved, and the insulating part can also increase the creepage distance between the pole and the top cover plate, so that the safety of the battery cell is improved.

Description

Technical Field

[0001] The present application relates to the field of energy technologies, and particularly to a battery cell, a battery pack, and an energy storage system. Background Art

[0002] Lithium batteries have characteristics such as high energy density and long cycle life, and are widely used in fields such as energy storage, electric vehicles, and standby power. As an important part of the structural components of a battery, the battery cover plate has functions such as sealing, insulation, current conduction, and shaping. Specifically, the battery cover plate includes a cover plate and a terminal post. The cover plate is provided with a mounting hole, and the terminal post is installed in the mounting hole. In order to improve the sealing performance of the battery cover plate, a sealing ring is sleeved on the outer periphery of the terminal post. However, the non-metallic part of the existing cover plate usually adopts an injection molding process. In order to facilitate demolding, the non-metallic part is provided with an inclination angle, a concave point, or a cut corner. In this way, after the battery cover plate is assembled, there is still a gap between the terminal post and the cover plate, and the insulating seal of the cover plate cannot be fully achieved, and safety problems such as arc ignition, explosion, etc. may occur during subsequent use of the battery. Summary of the Utility Model

[0003] The present application provides a battery cell, a battery pack, and an energy storage system to improve the sealing insulation of the battery cell cover plate and increase the creepage distance between the terminal post and the top cover sheet, thereby improving the safety of the battery cell.

[0004] In a first aspect, the present application provides a battery cell. The battery cell specifically includes a cover plate, a terminal post, and a housing. The housing is used to accommodate the core package, and the cover plate is covered on the housing. The cover plate is provided with a mounting hole for mounting the terminal post. The cover plate includes an upper plastic part, a top cover sheet, and a lower plastic part. The top cover sheet is located between the upper plastic part and the lower plastic part, and the lower plastic part is arranged close to the core package. The mounting hole penetrates through the upper plastic part, the top cover sheet, and the lower plastic part. A sealing ring is sleeved on the outer periphery of the terminal post. The sealing ring is located between the outer peripheral surface of the terminal post and the inner wall of the mounting hole, and the upper plastic part, the top cover sheet, and the lower plastic part are respectively in contact with the sealing ring. There is a gap between the inner wall of the lower plastic part and the outer peripheral surface of the sealing ring. The gap has two openings, one of the two openings is arranged towards the terminal post, and the other opening is arranged towards the top cover sheet. At least one of the two openings is covered with an insulating part.

[0005] In the battery cell of the present application, a sealed space is formed after the cover plate and the housing are closed, and the core package can be accommodated in this sealed space. When manufacturing the cover plate, first, the pole post and the sealing ring are installed in the top cover sheet, and the sealing ring is located between the pole post and the top cover sheet. At this time, the sealing ring is squeezed by the pole post and the top cover sheet, so that the pole post and the top cover sheet are relatively fixed, and the gap between the pole post and the top cover sheet is sealed, realizing the sealing performance of the top cover sheet. Subsequently, the upper plastic part and the lower plastic part are respectively injection-molded on both sides of the top cover sheet. To facilitate demolding, the inner wall of the lower plastic part is provided with an inclination angle, concave points or cut corners, etc., so that there is a gap between the outer peripheral surface of the sealing ring and the inner wall of the lower plastic part. When the electrolyte infiltrates into this gap, there is a risk of electrical connection between the pole post and the top cover sheet. In the present application, at least one of the two openings of the gap is covered with an insulating part, which can improve the phenomenon of the electrolyte electrically connecting the pole post and the top cover sheet, improve the sealing insulation between the sealing ring and the cover plate, and the insulating part can also increase the creepage distance between the pole post and the top cover sheet, thereby improving the safety of the battery cell.

[0006] The above-mentioned insulating part covers the opening of the gap. Specifically, the projection of the insulating part along the axial direction of the pole post covers the corresponding opening. This projection partially overlaps with the projection of the sealing ring along the axial direction, and this projection partially overlaps with the projection of the lower plastic part along the axial direction, so that the insulating part can seal this gap.

[0007] In a possible implementation manner, one of the above-mentioned openings of the gap is covered with an insulating part. The surface of the insulating part facing away from the gap that covers this one opening abuts against the pole post, and the sealing ring and the lower plastic part respectively abut against the surface of the insulating part that covers this one opening and faces the gap. In this technical solution, the insulating part seals the gap on the side of the gap facing the core package, and can block the electrolyte from infiltrating into the gap.

[0008] In practical applications, in order to fix the terminal post in the mounting hole, a step is provided on the outer peripheral surface of the terminal post, and the step is arranged close to the core package. The inner wall of the mounting hole is also correspondingly provided with a corresponding step so that the step and the corresponding step are in shape fit to limit the terminal post and prevent the terminal post from displacing relative to the cover plate. Specifically, the step of the terminal post includes two adjacent surfaces, one of the two surfaces is perpendicular to the axial direction of the terminal post, and the other of the two surfaces is located between the aforementioned one surface and the core package and is perpendicular to the aforementioned one surface. The aforementioned one surface and the aforementioned other surface are connected to form a step. One of the openings of the gap faces the aforementioned one surface. One side surface of the sealing ring perpendicular to the axial direction abuts against the aforementioned one surface, and one side surface of the insulating part covering the aforementioned one opening and facing away from the gap abuts against at least the aforementioned one surface. In this technical solution, both the sealing ring and the insulating part are arranged at the step, which can block the electrolyte from entering between the terminal post and the mounting hole at the position where the terminal post is close to the core package, thereby reducing the distance of electrolyte intrusion and further improving the safety of the battery cell.

[0009] In a possible implementation manner, the cross-sectional shape of the insulating part covering the aforementioned one opening along the axial direction of the terminal post is L-shaped, and the two surfaces of the step respectively abut against the insulating part covering the aforementioned one opening. In this way, a part of the insulating part extends in the direction towards the core package between the terminal post and the lower plastic part, which can block the electrolyte from entering the cover plate, and the L-shaped insulating part is convenient for positioning the position of the insulating part on the surface of the terminal post.

[0010] In another possible implementation manner, the cross-sectional shape of the insulating part covering the aforementioned one opening along the axial direction is linear, and the insulating part covering the aforementioned one opening can be embedded into one of the surfaces of the step, which can relatively fix the insulating part to the terminal post to avoid the insulating part displacing relative to the gap after long-term use.

[0011] In another possible implementation manner, the other opening of the gap is covered with an insulating part. One side surface of the insulating part covering the aforementioned other opening and facing away from the gap abuts against the top cover piece, and the sealing ring and the lower plastic part respectively abut against one side surface of the insulating part covering the aforementioned other opening and covering the gap. In this technical solution, the insulating part seals the gap on the side of the gap away from the core package, so that even if the electrolyte enters the gap, the insulating part can block the electrolyte from contacting the top cover piece.

[0012] In a possible implementation manner, the insulating part covering the aforementioned other opening can be embedded into one side surface of the top cover piece facing the gap, which can relatively fix the insulating part to the top cover piece to avoid the insulating part displacing relative to the gap after long-term use.

[0013] In a possible implementation, the insulating member can be an independent part for easy installation and disassembly. Specifically, the insulating member includes an insulating ring. The thickness of the insulating ring in the axial direction of the pole column is greater than or equal to 10 microns and less than or equal to 8 mm, so as to ensure the structural reliability of the insulating ring while enabling the insulating ring to play a good insulating role.

[0014] In this application, the insulating ring includes any one of an organic insulating ring, an inorganic insulating ring, and an organic-inorganic composite insulating ring. For example, the insulating ring can be made of one or more of ceramics, liquid crystal polymer (LCP), polyethylene glycol terephthalate (PET), polyethylene (PE), polypropylene (PP), fluororubber, polyphenylene sulfide (PPS).

[0015] In a possible implementation, the insulating member can also be directly fabricated on the surface of the pole column and / or the top cover sheet. Specifically, the insulating member can include an insulating film. The thickness of the insulating film is greater than or equal to 10 microns and less than or equal to 200 microns, so as to ensure the fixation of the insulating film on the surface of the pole column and / or the top cover sheet while enabling the insulating film to play a good insulating role. In another possible implementation, the insulating member can also include the above-mentioned insulating ring and the above-mentioned insulating film. In this way, the insulating ring and the insulating film can provide double insulating sealing to further improve the safety of the battery cell.

[0016] In a second aspect, this application provides a battery pack. The battery pack specifically includes a battery case, a power module, and at least one battery cell of the first aspect. Among them, the power module and at least one battery cell are located inside the battery case, and the power module is electrically connected to at least one battery cell. In the battery pack of this application, the insulating member of the battery cell cover plate can cover the gap between the sealing ring and the lower plastic part, which can not only improve the sealing insulation between the sealing ring and the cover plate, but also increase the creepage distance between the pole column and the top cover sheet, thereby improving the safety of the battery pack.

[0017] In a third aspect, this application provides an energy storage system. The energy storage system includes a power converter and at least one battery pack of the second aspect. The power converter is used to perform power conversion on the electric energy output by an external power source and then output it to at least one battery pack. In the energy storage system of this application, the insulating sealing and safety of the battery pack are relatively good, which is beneficial to improving the safety of the energy storage system. Description of the Drawings

[0018] Figure 1 Schematic diagram of the battery cell provided by the embodiment of this application;

[0019] Figure 2 Top view of the cover plate and the terminal post provided by the embodiment of the present application;

[0020] Figure 3 is Figure 2 A schematic cross-sectional view of the cover plate and the terminal post in the [FIGURE] along the A-A direction;

[0021] Figure 4 is Figure 3 A partial schematic view of the cover plate, the terminal post and the sealing ring in the [FIGURE];

[0022] Figure 5 A schematic view of the creepage distance between the terminal post and the top cover sheet without setting the insulating part;

[0023] Figure 6 is Figure 2 Another cross-sectional view of the cover plate and the terminal post in the [FIGURE] along the A-A direction;

[0024] Figure 7 is Figure 6 A partial schematic view of the cover plate, the terminal post and the sealing ring in the [FIGURE];

[0025] Figure 8 is Figure 2 Another cross-sectional view of the cover plate and the terminal post in the [FIGURE] along the A-A direction;

[0026] Figure 9 is Figure 8 A partial schematic view of the cover plate, the terminal post and the sealing ring in the [FIGURE];

[0027] Figure 10 is Figure 2 Another cross-sectional view of the cover plate and the terminal post in the [FIGURE] along the A-A direction;

[0028] Figure 11 is Figure 10 A partial schematic view of the cover plate, the terminal post and the sealing ring in the [FIGURE];

[0029] Figure 12 is Figure 2 Another cross-sectional view of the cover plate and the terminal post in the [FIGURE] along the A-A direction;

[0030] Figure 13 is Figure 12 A partial schematic view of the cover plate, the terminal post and the sealing ring in the [FIGURE];

[0031] Figure 14 Another partial schematic view of the cover plate, the terminal post and the sealing ring provided by the embodiment of the present application;

[0032] Figure 15 is Figure 2 Another cross-sectional view of the cover plate and the terminal post in the [FIGURE] along the A-A direction;

[0033] Figure 16 Schematic diagram of the battery pack provided by the embodiment of the present application.

[0034] Reference numerals:

[0035] 10 - battery cell

[0036] 11 - housing

[0037] 12 - cover plate

[0038] 13 - terminal

[0039] 14 - explosion-proof valve

[0040] 15 - sealing ring

[0041] 16 - gap

[0042] 17 - insulating part

[0043] 20 - battery pack

[0044] 21 - battery case

[0045] 121 - mounting hole

[0046] 122 - upper plastic part

[0047] 123 - top cover sheet

[0048] 124 - lower plastic part

[0049] 131 - positive terminal

[0050] 132 - negative terminal

[0051] 133 - first limiting groove

[0052] 161 - first opening

[0053] 162 - second opening

[0054] 171 - first insulating part

[0055] 172 - second insulating part

[0056] 173 - insulating film

[0057] 174 - insulating ring

[0058] 1211 - positive mounting hole

[0059] 1212 - negative mounting hole

[0060] 1231 - second limiting groove Detailed implementation manners

[0061] To make the objectives, technical solutions, and advantages of this application clearer, the following will further describe this application in detail with reference to the accompanying drawings.

[0062] To facilitate the understanding of the battery cell, battery pack, and energy storage system provided in the embodiments of this application, the following describes their application scenarios. The energy storage system of this application can be used in multiple application scenarios such as industrial and commercial energy storage and power station energy storage. Industrial and commercial energy storage can include, for example, small industrial and commercial (small factories, etc.) energy storage, medium-sized industrial and commercial energy storage, large-scale industrial and commercial energy storage, photovoltaic energy storage and charging stations energy storage, small and medium-sized microgrids (islands, etc.) energy storage, etc. Power station energy storage can include, for example, wind-solar-storage power stations, grid energy storage power stations, large-scale microgrid power stations, etc. In addition, the energy storage system can also be used in application scenarios such as data centers and vehicle charging stations.

[0063] In existing battery cells, the cover plate usually includes a top cover sheet made of a metal material and a plastic part made of a plastic material. Among them, the pole post can be directly installed in the mounting hole of the top cover sheet, and a sealing ring is provided between the pole post and the top cover sheet. After the pole post and the top cover sheet are installed, the plastic part can be directly formed on the surface of the top cover sheet by an injection molding process. To facilitate the removal of the cover plate from the injection mold, the inner wall of the injection mold can be provided with an inclination angle, concave points, or cut corners, resulting in a situation where the inner wall of the demolded plastic part does not fully match the shape of the sealing ring, and there are gaps. In this way, the electrolyte may penetrate into the cover plate along these gaps, causing the pole post and the top cover sheet to be electrically connected when the battery cell is working, thereby causing safety problems such as arc ignition and explosion.

[0064] In view of this, this application provides a battery cell, a battery pack, and an energy storage system to improve the sealing insulation of the battery cell cover plate and increase the creepage distance between the pole post and the top cover sheet, thereby improving the safety of the battery cell.

[0065] It should be noted that the terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to limit this application. As used in the specification and appended claims of this application, the singular forms "a", "an", "the", "above-mentioned", "said", and "this" are also intended to include expressions such as "one or more", unless clearly indicated to the contrary in the context.

[0066] References to "one embodiment" or "some embodiments" or the like described in this specification mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "comprising", "including", "having" and their variants mean "including but not limited to", unless otherwise specifically emphasized.

[0067] Figure 1 Schematic diagram of the battery cell provided for the embodiment of the present application. As Figure 1 shown, the battery cell 10 may include a housing 11, a cover plate 12, and a terminal post 13. The housing 11 is used to accommodate the core package. The cover plate 12 covers the housing 11 and forms a sealed space, and the aforementioned core package is located in this sealed space. Figure 2 Top view of the cover plate and the terminal post provided for the embodiment of the present application, Figure 3 is Figure 2 a cross-sectional schematic view of the cover plate and the terminal post along the A-A direction in Figure 2 and Figure 3 shown, the cover plate 12 is provided with mounting holes 121, the terminal post 13 is installed in the mounting holes 121, and the terminal post 13 is used for electrically connecting with the tab of the core package. The cover plate 12 includes an upper plastic part 122, a top cover piece 123, and a lower plastic part 124, and the top cover piece 123 is located between the upper plastic part 122 and the lower plastic part 124. The mounting holes 121 penetrate through the upper plastic part 122, the top cover piece 123, and the lower plastic part 124. In actual application, the mounting holes 121 include a positive electrode mounting hole 1211 and a negative electrode mounting hole 1212. The terminal post 13 includes a positive electrode post 131 and a negative electrode post 132. The positive electrode post 131 is installed in the positive electrode mounting hole 1211, and the negative electrode post 132 is installed in the negative electrode mounting hole 1212. Further, the cover plate 12 may further include an explosion-proof valve 14. When the battery cell 10 is in thermal runaway, the internal air pressure of the battery cell 10 increases, and by opening the explosion-proof valve 14, high-temperature gas and electrolyte can be released to avoid explosion of the battery cell 10. In order to improve the sealing performance of the cover plate 12, a sealing ring 15 is provided in the mounting holes 121. The sealing ring 15 is sleeved on the outer periphery of the terminal post 13, and the sealing ring 15 is located between the outer peripheral surface of the terminal post 13 and the inner wall of the mounting holes 121. The upper plastic part 122, the top cover piece 123, and the lower plastic part 124 are respectively in contact with the sealing ring 15.

[0068] When assembling the cover plate 12 and the terminal post 13, first relatively fix the terminal post 13 and the top cover piece 123, and install the sealing ring 15 between the terminal post 13 and the top cover piece 123. Then, directly fabricate the upper plastic part 122 and the lower plastic part 124 on the surface of the top cover piece 123 through an injection molding process. Figure 4 For Figure 3 a partial schematic view of the middle cover plate, the terminal post and the sealing ring. As Figure 3 and Figure 4 shown, for demolding, the inner wall of the lower plastic part 124 is provided with an inclination angle, concave points or cut corners, so that there is a gap 16 between the inner wall of the lower plastic part 124 and the outer peripheral surface of the sealing ring 15. The gap 16 has a first opening 161 and a second opening 162. The first opening 161 is arranged towards the terminal post 13, and the second opening 162 is arranged towards the top cover piece 123. At least one of the first opening 161 and the second opening 162 is covered with an insulating part 17. It should be noted that Figure 3 and Figure 4 the cross-sectional shape of the gap 16 along the axial direction of the terminal post 13 (as shown by the dotted line in Figure 3 ) is only for illustration, and in actual application, the gap 16 can also be of other shapes.

[0069] In the above embodiment, after the cover plate 12 and the housing 11 are covered, a sealed space is formed, and the core package can be accommodated in this sealed space. When manufacturing the cover plate 12, first install the terminal post 13 and the sealing ring 15 in the top cover piece 123, and the sealing ring 15 is located between the terminal post 13 and the top cover piece 123. At this time, the sealing ring 15 is squeezed by the terminal post 13 and the top cover piece 123, so that the terminal post 13 and the top cover piece 123 are relatively fixed, and the gap between the terminal post 13 and the top cover piece 123 is sealed, realizing the sealing performance of the top cover piece 123. Subsequently, the upper plastic part 122 and the lower plastic part 124 are respectively injection-molded on both sides of the top cover piece 123. In the gap 16 between the outer peripheral surface of the sealing ring 15 and the inner wall of the lower plastic part 124, at least one opening is covered with the insulating part 17, which can improve the phenomenon that the electrolyte electrically connects the terminal post 13 and the top cover piece 123, improve the sealing insulation between the sealing ring 15 and the cover plate 12, and the insulating part 17 can also increase the creepage distance between the terminal post 13 and the top cover piece 123, thereby improving the safety of the battery cell 10.

[0070] The above-mentioned insulating part 17 covers the corresponding opening of the gap 16, and specifically, it can be set that the projection of the insulating part 17 along the axial direction of the pole column 13 covers this opening. In this embodiment, this projection can partially overlap with the projection of the sealing ring 15 along the axial direction of the pole column 13, and this projection also partially overlaps with the projection of the lower plastic part 124 along the axial direction of the pole column 13, so that the insulating part 17 can seal the gap 16. In other words, the sealing ring 15 and the lower plastic part 124 respectively have overlapping parts with the insulating part 17. In this way, while improving the sealing performance, the insulating part 17 can also increase the creepage distance between the pole column 13 and the top cover sheet 123, thereby improving the safety of the battery cell 10. In addition, after the battery cell 10 is used for a long time, the sealing ring 15 and the insulating part 17 may undergo a small amount of deformation. The overlapping part between the sealing ring 15 and the insulating part 17 can prevent the sealing ring 15 from detaching from the insulating part 17, thus not affecting the overall sealing performance and insulation performance of the cover plate 12.

[0071] It should be noted that the creepage distance refers to the shortest path measured along the insulating surface between two conductive components or between a conductive component and the equipment protection interface. In the use case, the insulating material around the conductor will be polarized, resulting in the insulating material showing a charged phenomenon.

[0072] Figure 5 It is a schematic diagram of the creepage distance between the pole column and the top cover sheet without setting the insulating part. As Figure 5 shown, when the insulating part 17 is not set, the electrolyte in the battery cell 10 infiltrates into the cover plate 12 from between the pole column 13 and the lower plastic part 124. When the electrolyte infiltrates into the gap 16, the electrolyte spreads along the inner wall of the lower plastic part 124 in the gap 16. Therefore, the creepage distance between the pole column 13 and the lower plastic part 124 is the first distance MO.

[0073] Please continue to refer to Figure 3 and Figure 4, in some embodiments of the present application, the first opening 161 of the gap 16 is covered with an insulating member 17. One side surface of the insulating member 17 covering the first opening 161, which faces away from the gap 16, abuts against the pole post 13. The sealing ring 15 and the lower plastic part 124 respectively abut against one side surface of the insulating member 17 covering the gap 16. That is to say, the insulating member 17 seals the gap 16 on the side facing the core package, so as to block the electrolyte from entering the gap 16 from the first opening 161. In this embodiment, since the insulating member 17 covers the gap 16, the pole post 13 is isolated from the gap 16. Therefore, the creepage distance between the pole post 13 and the top cover sheet 123 is MN, specifically including a first distance MO and a second distance NO. Among them, the first distance MO is along the inner wall surface of the lower plastic part 124 located in the gap 16, and the second distance NO is along the surface of the lower plastic part 124 that abuts against the insulating member 17. In practical applications, the shorter the creepage distance, the easier it is for the pole post 13 and the top cover sheet 123 to be electrically connected, resulting in the pole post 13 being short-circuited and burned out, affecting the safety of the battery cell 10. Therefore, the insulating member 17 increases the creepage distance between the pole post 13 and the top cover sheet 123, which can improve the safety of the battery cell 10.

[0074] As Figure 4 and Figure 5 shown, in practical applications, in order to fix the pole post 13 in the mounting hole 121, a plurality of steps are provided on the outer peripheral surface of the pole post 13. Corresponding steps are also provided on the inner wall of the mounting hole 121 so that the above-mentioned plurality of steps and the corresponding steps are in shape fit and limit the pole post 13 to prevent the pole post 13 from displacing relative to the cover plate 12. The above-mentioned plurality of steps include a step close to the core package, and this step includes adjacent first surface S1 and second surface S2. Among them, the first surface S1 is perpendicular to the axial direction of the pole post 13, and the second surface S2 is located between the first surface S1 and the core package and is perpendicular to the first surface S1. The first surface S1 and the second surface S2 are connected to form a step. The first opening 161 of the gap 16 is arranged facing the first surface S1. One side surface of the sealing ring 15 perpendicular to the axial direction abuts against the first surface S1, and at least one side surface of the insulating member 17 covering the first opening 161, which faces away from the gap 16, abuts against the first surface S1. Both the sealing ring 15 and the insulating member 17 are arranged at the step, which can block the electrolyte from entering between the pole post 13 and the mounting hole 121 at the position where the pole post 13 is close to the core package, thereby reducing the distance of electrolyte intrusion and further improving the safety of the battery cell 10.

[0075] In the present application, the cross-sectional shape of the above-mentioned insulating member 17 in the axial direction of the pole post 13 is not specifically limited. As Figure 3 and Figure 4 shown, in one embodiment, the cross-sectional shape of the insulating member 17 covering the first opening 161 in the axial direction of the pole post 13 is a straight shape. Figure 6 ForFigure 2 Another schematic cross-sectional view of the middle cover plate and the pole column along the A-A direction Figure 7 is Figure 6 A partial schematic view of the middle cover plate, the pole column and the sealing ring. As Figure 6 and Figure 7 shown, in another embodiment, the cross-sectional shape of the insulating member 17 covering the first opening 161 along the axial direction of the pole column 13 is L-shaped. The first surface S1 and the second surface S2 of the above-mentioned step are respectively in contact with the insulating member 17. That is to say, the insulating member 17 includes a first part in contact with the first surface S1 and a second part in contact with the second surface S2. The first part and the second part are connected and form an L shape. In this embodiment, the second part of the insulating member 17 extends in the direction towards the core package between the pole column 13 and the lower plastic part 124, so as to prevent the electrolyte from infiltrating into the cover plate 12 and facilitate positioning the insulating member 17 at the corresponding position on the surface of the pole column 13. Correspondingly, the creepage distance between the pole column 13 and the top cover piece 123 includes a first distance MO and a second distance NO. Among them, the first distance MO is along the inner wall surface of the lower plastic part 124 located in the gap 16, and the second distance NO is along the surface of the lower plastic part 124 in contact with the insulating member 17.

[0076] In the above embodiment, the insulating member 17 can be arranged relatively independently of the pole column 13. Figure 8 is Figure 2 Another schematic cross-sectional view of the middle cover plate and the pole column along the A-A direction Figure 9 is Figure 8 A partial schematic view of the middle cover plate, the pole column and the sealing ring. As Figure 8 and Figure 9 shown, the cross-sectional shape of the insulating member 17 covering the first opening 161 along the axial direction of the pole column 13 is a straight shape, and the insulating member 17 can be embedded in the first surface S1 of the pole column 13. Specifically, a first limiting groove 133 is formed on the first surface S1 of the pole column 13, and the insulating member 17 is embedded in the first limiting groove 133, so that the insulating member 17 is relatively fixed to the pole column 13 to prevent the insulating member 17 from displacing relative to the gap 16. In this embodiment, the creepage distance between the pole column 13 and the top cover piece 123 includes a first distance MO and a second distance NO, where the first distance MO is along the inner wall surface of the lower plastic part 124 located in the gap 16, and the second distance NO is along the surface of the lower plastic part 124 in contact with the insulating member 17.

[0077] Figure 10 is Figure 2 Another schematic cross-sectional view of the middle cover plate and the pole column along the A-A direction Figure 11 is Figure 10 A partial schematic view of the middle cover plate, the pole column and the sealing ring. As Figure 10 and Figure 11As shown, in some other embodiments of the present application, the second opening 162 of the gap 16 is covered with an insulating member 17. One surface of the insulating member 17 covering the second opening 162, which faces away from the gap 16, abuts against the top cover sheet 123, and the sealing ring 15 and the lower plastic part 124 respectively abut against one surface of the insulating member 17 covering the gap 16. In this embodiment, the insulating member 17 covering the second opening 162 seals the gap 16 on the side of the gap 16 away from the core package. In this way, even if the electrolyte enters the gap 16, the insulating member 17 can prevent the electrolyte from contacting the top cover sheet 123. Correspondingly, the creepage distance between the pole column 13 and the top cover sheet 123 includes a first distance MO and a second distance NO, where the first distance MO is along the inner wall surface of the lower plastic part 124 located in the gap 16, and the second distance NO is along the surface of the lower plastic part 124 that abuts against the insulating member 17.

[0078] In the above embodiment, the insulating member 17 covering the second opening 162 can be arranged relatively independently of the top cover sheet 123. Figure 12 For Figure 2 Another cross-sectional schematic diagram of the middle cover plate and the pole column along the A-A direction, Figure 13 For Figure 12 A partial schematic diagram of the middle cover plate, the pole column and the sealing ring. As Figure 12 And Figure 13 As shown, the cross-sectional shape of the insulating member 17 covering the second opening 162 along the axial direction of the pole column 13 is a straight shape, and the insulating member 17 can be embedded in one surface of the top cover sheet 123 facing the gap 16. Specifically, a second limiting groove 1231 is formed on one surface of the top cover sheet 123 facing the gap 16, and the insulating member 17 is embedded in the second limiting groove 1231, so that the insulating member 17 is relatively fixed to the top cover sheet 123, preventing the insulating member 17 from displacing relative to the gap 16. In this embodiment, the creepage distance between the pole column 13 and the top cover sheet 123 includes a first distance MO and a second distance NO, where the first distance MO is along the inner wall surface of the lower plastic part 124 located in the gap 16, and the second distance NO is along the surface of the lower plastic part 124 that abuts against the insulating member 17.

[0079] Figure 14 For another partial schematic diagram of the cover plate, the pole column and the sealing ring provided by the embodiment of the present application. As Figure 14As shown, in some other embodiments, both openings of the gap 16 are covered with an insulating member 17. Specifically, the first opening 161 of the gap 16 is covered with a first insulating member 171, and the second opening 162 is covered with a second insulating member 172. The first insulating member 171 and the second insulating member 172 seal the gap 16, further improving the sealing performance between the cover plate 12 and the pole column 13. In this embodiment, the creepage distance between the pole column 13 and the top cover piece 123 includes a first distance MO, a second distance NO, and a third distance N'O. Among them, the first distance MO is along the inner wall surface of the lower plastic part 124 located in the gap 16, the second distance NO is along the surface of the lower plastic part 124 that abuts against the first insulating member 171, and the third distance N'O is along the surface of the lower plastic part 124 that abuts against the second insulating member 172.

[0080] In the above embodiment, the insulating member 17 can be an independent part for easy installation and disassembly. Specifically, the insulating member 17 is an insulating ring. In some embodiments of the present application, the thickness of the insulating ring in the axial direction of the pole column 13 is greater than or equal to 10 microns and less than or equal to 8 millimeters, so as to ensure the structural reliability of the insulating ring while enabling the insulating ring to play a better insulating role.

[0081] In the present application, the insulating ring includes any one of an organic insulating ring, an inorganic insulating ring, and an organic-inorganic composite insulating ring. For example, the insulating ring can be made of at least one of ceramics, liquid crystal polymer (LCP), polyethylene glycol terephthalate (PET), polyethylene (PE), polypropylene (PP), fluororubber, and polyphenylene sulfide (PPS).

[0082] Figure 15 For Figure 2 Another cross-sectional schematic diagram of the middle cover plate and the pole column along the A-A direction. As Figure 15 As shown on the right side in the figure, in some other embodiments, the insulating member 17 can also be directly made on the surface of the pole column 13 and / or the top cover piece 123. Specifically, the insulating member 17 can be an insulating film 173. That is to say, the insulating film 173 can replace the insulating ring. In one embodiment, the thickness of the insulating film 173 is greater than or equal to 10 microns and less than or equal to 200 microns, so as to ensure the fixation of the insulating film 173 on the surface of the pole column 13 and / or the top cover piece 123 while enabling the insulating film 173 to play a better insulating role. In this embodiment, the position and shape of the insulating film 173 can be set according to the insulating ring in any of the above embodiments.

[0083] In the above embodiments, the insulating film 173 can adopt any one or more of the processes of vacuum coating, electroplating, electrophoresis, chemical coating, spraying, inkjet printing, brushing, scraping, and dip coating, so that the insulating film 173 can be directly fabricated on the outer peripheral surface of the terminal post 13 and / or the inner wall surface of the mounting hole 121.

[0084] As Figure 15 shown in the left side of the figure, in another embodiment, the insulating member 17 may also include the above-mentioned insulating ring 174 and the above-mentioned insulating film 173. In this way, the insulating ring 174 and the insulating film 173 can provide double insulating sealing performance to further improve the safety of the battery cell 10.

[0085] Based on the same technical concept, the present application also provides a battery pack. Figure 16 It is a schematic diagram of the battery pack provided by the embodiment of the present application. As Figure 16 shown, the battery pack 20 specifically includes a battery case 21, a power module, and at least one battery cell 10 of any of the above embodiments. Among them, the power module and at least one battery cell 10 are located inside the battery case 21, and the power module is electrically connected to at least one battery cell 10. The power module can be used to manage the charging and discharging of the battery cell 10 and obtain data such as the voltage, current, temperature, state of charge (SOC) parameter, and state of health (SOH) parameter of the battery cell 10. In the battery pack 20 of the present application, the cover plate 12 of the battery cell 10 is provided with an insulating member 17, and the insulating member 17 can cover the gap between the sealing ring 15 and the lower plastic part 124. In this way, not only can the sealing insulation performance between the sealing ring 15 and the cover plate 12 be improved, but also the creepage distance between the terminal post 13 and the top cover sheet 123 can be increased, thereby improving the safety of the battery pack 20.

[0086] Based on the same technical concept, the present application also provides an energy storage system. The energy storage system includes a power converter and at least one battery pack 20. The power converter is used to perform power conversion on the electric energy output by an external power supply and then output it to the aforementioned at least one battery pack 20. In the energy storage system of the present application, the insulating sealing performance and safety of the battery pack 20 are relatively good, which is beneficial to improving the safety of the energy storage system.

[0087] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A battery cell, characterized in that: The battery cell comprises a cover plate, a pole and a shell, wherein the shell is used to accommodate the core package, and the cover plate is arranged on the shell; The cover plate is provided with a mounting hole, and the mounting hole is used to mount the pole; the cover plate comprises an upper plastic part, a top cover sheet and a lower plastic part, the top cover sheet is located between the upper plastic part and the lower plastic part, and the lower plastic part is arranged close to the core package; the mounting hole passes through the upper plastic part, the top cover sheet and the lower plastic part; The outer circumference of the pole is sleeved with a sealing ring, the sealing ring is located between the outer circumferential surface of the pole and the inner wall of the mounting hole, and the upper plastic part, the top cover sheet and the lower plastic part are respectively in contact with the sealing ring; There is a gap between the outer peripheral surface of the sealing ring and the inner wall of the lower plastic part; the gap has two openings, one of the two openings is arranged toward the pole, and the other opening is arranged toward the top cover sheet; at least one of the two openings is covered with an insulating part.

2. The battery cell according to claim 1, characterized in that: The projection of the insulating member along the axial direction of the pole covers the corresponding opening, the projection partially overlaps with the projection of the sealing ring along the axial direction, and the projection partially overlaps with the projection of the lower plastic member along the axial direction.

3. The battery cell according to claim 1 or 2, characterized in that: One of the openings is covered by the insulating member, a side surface of the insulating member covering one of the openings facing away from the gap abuts against the pole, and the sealing ring and the lower plastic member respectively abut against a side surface of the insulating member covering one of the openings covering the gap.

4. The battery cell according to claim 3, characterized in that: The outer peripheral surface of the pole is provided with a step, and the step is arranged close to the core package; The step includes two adjacent surfaces, one of the two surfaces is perpendicular to the axial direction of the pole, the other of the two surfaces is located between the one of the surfaces and the core package and is arranged perpendicular to the one of the surfaces, the one of the surfaces is connected to the other surface and forms the step; and one of the openings is arranged toward the one of the surfaces; A side surface of the sealing ring perpendicular to the axial direction abuts against one of the surfaces; a side surface of the insulating member covering one of the openings and facing away from the gap abuts against at least one of the surfaces.

5. The battery cell according to claim 4, characterized in that: The insulating member covering the one of the openings has an L-shaped cross-section along the axial direction, and the two surfaces are respectively in contact with the insulating member covering the one of the openings.

6. The battery cell according to claim 4, characterized in that: The cross-sectional shape of the insulating member covering one of the openings along the axial direction is a straight line, and the insulating member covering one of the openings is embedded in one of the surfaces.

7. The battery cell according to claim 1 or 2, characterized in that: The other opening is covered by the insulating member, a side surface of the insulating member covering the other opening facing away from the gap abuts against the top cover sheet, and the sealing ring and the lower plastic member respectively abut against a side surface of the insulating member covering the other opening covering the gap.

8. The battery cell according to claim 7, characterized in that: The insulating member covering the other opening is embedded in a side surface of the top cover sheet facing the gap.

9. The battery cell according to claim 1 or 2, characterized in that: The insulating member comprises an insulating ring, and a thickness of the insulating ring along the axial direction of the pole is greater than or equal to 10 micrometers and less than or equal to 8 millimeters.

10. The battery cell according to claim 1 or 2, characterized in that: The insulating member includes an insulating film, and a thickness of the insulating film is greater than or equal to 10 micrometers and less than or equal to 200 micrometers.

11. A battery pack, characterized in that: The battery pack comprises a battery case, a power module and at least one battery cell as claimed in any one of claims 1 to 10, wherein the power module and at least one battery cell are located in the battery case, and the power module is electrically connected to at least one battery cell.

12. 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 11, wherein the power converter is used to convert the electric energy output by an external power source and output the electric energy to at least one of the battery packs.

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