Battery

Abstract

The utility model relates to the technical field of batteries, and discloses a battery, which comprises a shell with an accommodating cavity with an opening; the battery cell is arranged in the accommodating cavity and is provided with a positive tab and a negative tab, and the negative tab is connected with the shell; the shell cover covers the opening and comprises a first shell cover body, a second shell cover body and a first insulating part, the first shell cover body is connected with the shell, the first insulating part is located between the first shell cover body and the second shell cover body, a first through hole is formed in the first shell cover body, and a second through hole corresponding to the first through hole is formed in the first insulating part; the positive tab comprises a connecting part connected with the battery cell and an extending part connected with the second shell cover; and the second insulating part covers one side, deviating from the shell cover, of the extension part of the positive tab and is in contact with the second shell cover. And the second insulating part prevents the negative plate of the battery cell from contacting with the second shell cover and the positive lug, so that short circuit caused by contact between the negative plate of the inner ring of the battery cell and the second shell cover and the positive lug is avoided.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to batteries. Background Technology

[0002] With the development and progress of technology, people's demand for wearable devices, such as Bluetooth headsets, sports watches, and smart bracelets, is growing. These smart wearable devices often require small rechargeable button batteries for power. Button batteries are also known as coin cells.

[0003] A button cell battery typically includes a casing, a battery cell and electrolyte disposed within the casing, and a cover fixed to the casing. The cover includes a first cover, a second cover, and an insulating layer. The first cover is welded to the casing, and the casing is connected to the negative electrode tab of the battery cell. The second cover is connected to the positive electrode tab of the battery cell. The insulating layer is disposed between the first and second covers. An insulating element is disposed on the side of the battery cell facing the cover, thus insulating the negative electrode from the second cover and the positive electrode tab. When welding the negative electrode tab to the casing, a welding pin needs to be inserted through a through-hole in the battery cell, and through-holes also need to be made in the insulating element. This can cause the inner ring of the battery cell's negative electrode to come into contact with the second cover or the positive electrode tab, resulting in a short circuit and posing a safety risk. Utility Model Content

[0004] In view of this, the present invention provides a battery to solve the problem of short circuit between the negative electrode of the inner ring of the battery cell and the second shell cover or positive electrode tab.

[0005] This utility model provides a battery, comprising: a casing with an open receiving cavity; a battery cell disposed within the receiving cavity, the battery cell having a positive electrode tab and a negative electrode tab, the negative electrode tab being connected to the casing; a casing cover disposed at the opening, the casing cover comprising a first casing cover, a second casing cover, and a first insulating member, the first casing cover being connected to the casing, the first insulating member being located between the first casing cover and the second casing cover, the first casing cover having a first through hole, the first insulating member having a second through hole corresponding to the first through hole, the positive electrode tab including a connecting portion connected to the battery cell and an extension portion connected to the second casing cover; and a second insulating member covering the side of the extension portion of the positive electrode tab away from the casing cover and in contact with the second casing cover.

[0006] Beneficial effects: By covering the positive electrode tab on the side away from the casing and connecting it to the second casing, the negative electrode plate of the inner ring of the cell can be prevented from short-circuiting with the second casing and the positive electrode tab. Furthermore, by covering the positive electrode tab on the side away from the casing and eliminating the insulating element on the end face of the cell, a gap is formed between the second insulating element and the end face of the cell. Compared to the prior art where the end face of the cell is insulated, the electrolyte can only enter the electrode from the lower end face of the cell. This embodiment, by forming a gap between the end face of the cell and the second insulating element, allows the electrolyte to enter the electrode from both the gap and the lower end face of the cell. This improves the absorption of electrolyte by the cell during the electrolyte injection process, thereby increasing the CPK of the injected electrolyte.

[0007] In one alternative embodiment, the second cover is located on the side of the first cover away from the battery cell, and the second cover has a lower protrusion protruding toward the side where the battery cell is located, with a portion of the lower protrusion located in the first through hole; or, the second cover is located on the side of the first cover close to the battery cell, and the second cover includes an upper protrusion protruding toward the side of the first cover, with a portion of the upper protrusion located in the first through hole.

[0008] Beneficial effects: When the second cover is located on the side of the first cover closer to the cell, the welding area of ​​the positive electrode tab and the second cover is larger, which can improve the welding strength and welding stability of the positive electrode tab. It can also avoid the insulating adhesive on the positive electrode tab, preventing the weld marks of the positive electrode tab and the second cover from being too close to the insulating adhesive, causing the insulating adhesive to melt.

[0009] In one optional embodiment, when the second cover has a lower protrusion, an injection hole is provided on the lower protrusion, and the second insulating member has a third through hole corresponding to the injection hole, the diameter of the third through hole being larger than the diameter of the injection hole; and / or, the outer radius R1 of the second insulating member is less than or equal to the length L of the extension.

[0010] Beneficial effects: It does not affect the injection efficiency during liquid injection, ensuring efficiency and preventing the third through hole from being too small and obstructing the injection hole, thus reducing injection efficiency. The outer radius of the second insulating component is less than or equal to the length of the extension, preventing wrinkles in the second insulating component and reducing the risk of short circuits.

[0011] In one alternative embodiment, the battery cell has a fourth through hole corresponding to the first through hole, the second insulating member has a third through hole corresponding to the fourth through hole, the diameter of the third through hole is smaller than the diameter of the fourth through hole, and / or, in the thickness direction of the battery, the projection of the third through hole is located within the projection of the fourth through hole.

[0012] Beneficial effects: The diameter of the third through hole is smaller than that of the fourth through hole, which allows the second insulating component to completely cover the battery cell, effectively preventing the negative electrode tab of the inner ring of the battery cell from contacting the lower protrusion and the positive electrode tab. This achieves good insulation between the negative electrode tab of the inner ring of the battery cell and the lower protrusion and the positive electrode tab, avoiding short circuits between the negative electrode plate of the battery cell and the lower protrusion. After assembly, the short circuit rate is reduced to 0%. At the same time, the projection of the third through hole is located within the projection of the fourth through hole, which ensures that there is a second insulating layer between the inner side of the battery cell and the second shell cover. The projections of the electrode plates on the inner side of the battery cell are all covered by the second insulating layer.

[0013] In one alternative embodiment, when the second cover has a downward protrusion, the outer diameter D1 of the second insulating member is greater than the diameter D3 of the downward protrusion and smaller than the outer diameter D2 of the first cover.

[0014] Beneficial effects: The outer diameter D1 of the second insulating part is larger than the diameter of the lower protrusion and smaller than the outer diameter D2 of the first shell cover 301. This not only avoids short circuits between the negative electrode plate of the inner ring of the battery cell and the lower protrusion and positive electrode tab, but also controls the amount of material used in the second insulating part and reduces costs.

[0015] In one alternative embodiment, a third insulating member is provided on the lower surface of the first housing cover, and the projection of the third insulating member on the lower surface of the first housing cover at least partially overlaps with the projection of the second insulating member on the lower surface of the first housing cover.

[0016] Beneficial effects: The third insulating component insulates the positive electrode tab from the first cover, preventing short circuits caused by contact between the positive electrode tab and the first cover, and achieving good insulation between the positive electrode tab and the first cover.

[0017] In one alternative implementation, the edge of the third insulator extends beyond the edge of the second insulator.

[0018] Beneficial effects: When the third and second insulating components do not overlap, less material is used for both components, saving costs. If the third and second insulating components completely overlap, and the third insulating component is also placed on the lower protrusion, the insulation effect between the negative electrode plate of the inner ring of the battery cell and the lower protrusion and positive electrode tab is better.

[0019] In one alternative embodiment, a protective element is provided on the side of the positive electrode tab facing the connection between the first cover and the housing.

[0020] Beneficial effects: The protective device can prevent short circuits caused by contact between the positive electrode tab and the first cover or housing, achieving good insulation between the positive electrode tab and the first cover or housing, and reducing the risk of short circuits.

[0021] In one alternative embodiment, the projection of the protective member on the lower surface of the first housing cover at least partially overlaps with the projection of the second insulating member on the lower surface of the first housing cover.

[0022] Beneficial effects: When the protective component and the second insulating component do not overlap, the material usage of the protective component and the second insulating component is less, resulting in lower cost. When the protective component and the second insulating component completely overlap, the insulation effect between the positive electrode tab and the first cover or housing is better, further reducing the risk of short circuit.

[0023] In one alternative embodiment, a sealing element is provided on the side of the lower protrusion facing away from the battery cell, and the sealing element seals the liquid injection hole.

[0024] Beneficial effect: After injection, the injection port is sealed with a sealing device to prevent electrolyte leakage. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a cross-sectional view of a battery according to an embodiment of the present utility model;

[0027] Figure 2 for Figure 1 The diagram shows the structure of the cover, the second insulating component, and the third insulating component.

[0028] Figure 3 for Figure 2 The diagram shows the top view of the shell cover, second insulating component, third insulating component, and positive electrode plate before bending.

[0029] Figure 4 for Figure 1 The diagram shows the structure of the battery cell;

[0030] Figure 5 This is a partial cross-sectional view of another battery according to an embodiment of the present utility model;

[0031] Figure 6 A cross-sectional view of a battery in the prior art;

[0032] Figure 7 for Figure 6 The image shows a top view of the battery with the casing removed.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Shell;

[0035] 2. Battery cell; 201. Negative electrode tab; 202. Positive electrode tab; 2021. Connecting part; 2022. Extension part; 203. Positive electrode plate; 204. Separator; 205. Negative electrode plate; 206. Fourth through hole;

[0036] 3. Shell cover; 301. First shell cover; 3011. First through hole; 302. Second shell cover; 3021. Lower protrusion; 30211. Liquid injection hole; 3022. Upper protrusion; 303. First insulating component; 3031. Second through hole;

[0037] 4. Second insulating component; 401. Third through hole;

[0038] 5. Third insulating component;

[0039] 6. Sealing components. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0041] The following is combined Figures 1 to 5 The following describes embodiments of the present invention.

[0042] According to an embodiment of the present invention, a battery is provided, comprising: a housing 1, a battery cell 2, a housing cover 3, and a second insulating member 4. The housing 1 has an open receiving cavity; the battery cell 2 is disposed within the receiving cavity and has a positive electrode tab 202 and a negative electrode tab 201, the negative electrode tab 201 being connected to the housing 1; the housing cover 3 is disposed at the opening and includes a first housing cover 301, a second housing cover 302, and a first insulating member 303. The first housing cover 301 is connected to the housing 1, and the first insulating member 303 is located between the first housing cover 301 and the second housing cover 302. Between the two components, the first housing cover 301 has a first through hole 3011, and the first insulating member 303 has a second through hole 3031 corresponding to the first through hole 3011. The positive electrode tab 202 includes a connecting part 2021 connected to the battery cell 2 and an extension part 2022 connected to the second housing cover 302. The second insulating member 4 covers the side of the extension part 2022 of the positive electrode tab 202 away from the housing cover 3 and contacts the second housing cover 302 to prevent the negative electrode plate 205 of the battery cell 2 from contacting the second housing cover 302 and the positive electrode tab 202.

[0043] In the battery using this embodiment, the second insulating member covers the side of the positive electrode tab away from the casing and is connected to the second casing. This avoids short circuits between the negative electrode plate of the inner ring of the cell and the second casing and the positive electrode tab. Furthermore, by covering the positive electrode tab on the side away from the casing and removing the insulating member from the end face of the cell, a gap is formed between the second insulating member and the end face of the cell. Compared to the prior art where the end face of the cell has an insulating layer, the electrolyte can only enter the electrode from the lower end face of the cell. This embodiment, by forming a gap between the end face of the cell and the second insulating member, allows the electrolyte to enter the electrode from both the gap and the lower end face of the cell. This improves the cell's absorption of electrolyte during the electrolyte injection process, thereby increasing the CPK of the injected electrolyte.

[0044] It should be noted that CPK is an abbreviation for Process Capability Index.

[0045] In one embodiment, such as Figure 1 As shown, the second cover 302 is located on the side of the first cover 301 facing away from the battery cell 2. The second cover 302 has a lower protrusion 3021 protruding towards the side where the battery cell 2 is located, and part of the lower protrusion 3021 is located inside the first through hole 3011. Through the layered design of the first cover 301 and the second cover 302, the first cover 301 directly faces the battery cell 2, providing initial protection, while the second cover 302 acts as an external protective barrier to resist external impacts or environmental influences, providing more comprehensive protection for the battery cell 2. The lower protrusion 3021 facilitates connection with the positive electrode tab 202, achieving an effective connection between the tab and the second cover 302.

[0046] It is understood that in another embodiment, such as Figure 5 As shown, the second cover 302 is located on the side of the first cover 301 near the battery cell 2. The second cover 302 includes an upper protrusion 3022 protruding towards the side of the first cover 301, and a portion of the upper protrusion 3022 is located within the first through hole 3011. The larger welding area of ​​the positive electrode tab 202 and the second cover 302 can improve the welding strength and welding stability of the positive electrode tab 202. It can also avoid the insulating adhesive on the positive electrode tab 202, preventing the solder joints of the positive electrode tab 202 and the second cover 302 from being too close to the insulating adhesive, which could cause the insulating adhesive to melt.

[0047] In one embodiment, such as Figure 1 and Figure 2As shown, the lower protrusion 3021 has an injection hole 30211, and the second insulating member 4 has a third through hole 401 corresponding to the injection hole 30211. The diameter of the third through hole 401 is larger than the diameter of the injection hole 30211. If the diameter of the third through hole 401 is smaller than the diameter of the injection hole 30211, the second insulating member 4 will block part of the injection hole 30211, resulting in a fast injection speed and severely affecting the injection efficiency. Therefore, the diameter of the third through hole 401 of the second insulating member 4 is larger than the diameter of the injection hole 30211 of the lower protrusion 3021. This ensures that the injection efficiency is not affected during injection and thus avoids the injection efficiency being affected by the excessively small third through hole 401 blocking the injection hole 30211.

[0048] In one embodiment, such as Figure 1 and Figure 2 As shown, the battery cell 2 has a fourth through hole 206 corresponding to the first through hole 3011, and the diameter of the third through hole 401 is smaller than the diameter of the fourth through hole 206. If the diameter of the third through hole 401 is larger than the diameter of the fourth through hole 206, the lower protrusion 3021 and the positive electrode 203 can easily come into contact with the negative electrode 205 of the inner ring of the battery cell 2 and short-circuit. Therefore, the diameter of the third through hole 401 is smaller than the diameter of the fourth through hole 206, so that the second insulating member 4 completely covers the battery cell 2, effectively preventing the negative electrode 201 of the inner ring of the battery cell 2 from contacting the lower protrusion 3021 and the positive electrode 202, achieving good insulation between the negative electrode 201 of the inner ring of the battery cell 2 and the lower protrusion 3021 and the positive electrode 202, avoiding short circuit between the negative electrode 205 of the battery cell 2 and the lower protrusion 3021, and reducing the short-circuit rate to 0% after assembly.

[0049] In one embodiment, such as Figure 1 and Figure 2 As shown, the outer diameter D1 of the second insulating member 4 is larger than the diameter D3 of the lower protrusion 3021 and smaller than the outer diameter D2 of the first cover 301. If the outer diameter of the second insulating member 4 is too large, more material is used, resulting in higher costs. If the outer diameter of the second insulating member 4 is too small, it cannot completely cover the lower protrusion 3021, which could easily lead to a short circuit between the negative electrode tab 201 of the inner ring of the battery cell 2 and the lower protrusion 3021 and positive electrode tab 202. Therefore, the outer diameter D1 of the second insulating member 4 is larger than the diameter of the lower protrusion 3021 and smaller than the outer diameter D2 of the first cover 301. This not only avoids short circuits between the negative electrode plate 205 of the inner ring of the battery cell 2 and the lower protrusion 3021 and positive electrode tab 202, but also controls the amount of material used in the second insulating member 4, reducing costs.

[0050] In one embodiment, the outer radius R1 of the second insulating member 4 is less than or equal to the length L of the extension 2022. If the outer radius of the second insulating member 4 exceeds the side of the positive electrode tab 202 away from the center of the cell 2, causing wrinkles to form on the end of the second insulating member 4 near the cell 2 body, it may lead to uneven thickness or local failure of the second insulating member 4, increasing the risk of short circuit. Therefore, by ensuring that the outer radius of the second insulating member 4 is less than or equal to the length of the extension 2022, wrinkles in the second insulating member 4 can be avoided, reducing the risk of short circuit.

[0051] In one embodiment, a third insulating member 5 is provided on the lower surface of the first housing cover 301. The third insulating member 5 is used to prevent the first housing cover 301 from contacting the positive electrode tab 202. The provision of the third insulating member 5 insulates the positive electrode tab 202 from the first housing cover 301, avoiding short circuits caused by contact between the positive electrode tab 202 and the first housing cover 301, and achieving good insulation between the positive electrode tab 202 and the first housing cover 301.

[0052] Furthermore, the first insulating component 303, the second insulating component 4, and the third insulating component 5 are all made of insulating adhesive, which has advantages such as excellent electrical insulation properties and good mechanical properties.

[0053] In one embodiment, the projection of the third insulating member 5 onto the lower surface of the first housing cover 301 and the projection of the second insulating member 4 onto the lower surface of the first housing cover 301 may not overlap, or may at least partially overlap. When the third insulating member 5 and the second insulating member 4 do not overlap, the amount of material used for the third insulating member 5 and the second insulating member 4 is less, saving costs. If the third insulating member 5 and the second insulating member 4 completely overlap, and the third insulating member 5 is also disposed on the lower protrusion 3021, the insulation effect between the negative electrode plate 205 of the inner ring of the battery cell 2 and the lower protrusion 3021 and the positive electrode tab 202 is better. In one embodiment, the edge of the third insulating member extends beyond the edge of the second insulating member, and the edge of the third insulating member extends beyond the edge of the battery cell, thereby isolating the battery cell and the housing cover and preventing the internal electrode plate of the battery cell from contacting the housing cover, which could lead to a short circuit.

[0054] In one embodiment, a protective element is provided on the side of the positive electrode tab 202 facing the connection between the first cover 301 and the housing 1. The protective element is used to prevent the positive electrode tab 202 from contacting the first cover 301 or the housing 1. The protective element can prevent the positive electrode tab 202 from short-circuiting due to contact with the first cover 301 or the housing 1, achieving good insulation between the positive electrode tab 202 and the first cover 301 or the housing 1, and reducing the risk of short circuit.

[0055] Specifically, the projection of the protective element on the lower surface of the first housing cover 301 and the projection of the second insulating element 4 on the lower surface of the first housing cover 301 may not overlap, or may at least partially overlap. When the protective element and the second insulating element 4 do not overlap, the amount of material used for both is less, resulting in lower cost. When the protective element and the second insulating element 4 completely overlap, the insulation effect between the positive electrode tab 202 and the first housing cover 301 or the housing 1 is better, further reducing the risk of short circuit.

[0056] In one embodiment, a sealing member 6 is provided on the side of the lower protrusion 3021 facing away from the battery cell 2, and the sealing member 6 seals the liquid injection hole 30211. After liquid injection, the liquid injection hole is sealed by the sealing member 6 to prevent electrolyte leakage. Furthermore, the sealing member 6 is welded to the lower protrusion 3021.

[0057] Furthermore, the first cover 301 is made of metal and is welded to the housing 1. The first cover 301 and the housing 1 serve as the negative terminal of the battery. The second cover 302 is also made of metal and serves as the positive terminal of the battery. The second cover 302, serving as the positive terminal, is insulated from the first cover 301, serving as the negative terminal, by the first insulating member 303. The lower protrusion 3021 protrudes towards the receiving cavity, allowing the lower protrusion 3021 to directly face the inside of the housing 1, facilitating connection between the lower protrusion 3021 and the positive electrode tab 202.

[0058] Specifically, the battery also includes an electrolyte, which is disposed inside the casing 1. The cell 2 includes a positive electrode 203, a negative electrode 205, a separator 204, a positive electrode tab 202, and a negative electrode tab 201. The negative electrode tab 201 is connected to the negative electrode 205, and the positive electrode tab 202 is connected to the positive electrode 203. The positive electrode 203 and the negative electrode 205 are insulated and isolated by the separator 204. A fourth through hole 206 is provided in the middle of the cell 2. An insulating adhesive is applied to the side of the positive electrode tab 202 facing away from the cover 3, and this insulating adhesive is applied to the lower protrusion 3021, so that the lower protrusion 3021, the positive electrode tab 202 and the negative electrode 205 of the cell 2 are insulated, avoiding the risk of short circuit between the negative electrode 205 of the inner ring of the cell 2 and the lower protrusion 3021 and the positive electrode tab 202; the insulating adhesive is transferred from the end face of the core to the lower protrusion 3021 and the positive electrode tab 202 of the second housing 1, improving the cell 2's absorption and storage capacity of electrolyte during electrolyte injection, increasing the electrolyte injection volume (CPK), and improving the battery cycle capacity by increasing the electrolyte injection volume. The positive electrode 203 is connected to the lower protrusion 3021 through the positive electrode tab 202. An insulating adhesive is applied to the lower surface of the first cover 301, so that the positive electrode tab 202 of the cell 2 is insulated from the first cover 301, and the negative electrode 205 is connected to the housing 1 through the negative electrode tab 201.

[0059] In existing technologies, such as Figure 6 and Figure 7As shown, a second insulating component 4 is provided on the end face of the battery cell 2. When welding the negative electrode tab 201 to the housing 1, a welding needle needs to be inserted through the through hole of the battery cell 2, and a through hole also needs to be made on the second insulating component 4. The diameter of the through hole of the second insulating component 4 needs to be larger than the diameter of the through hole of the battery cell 2 to ensure that the negative electrode tab 201 is welded to the housing 1. Therefore, the inner ring negative electrode of the battery cell 2 cannot be covered by the second insulating component 4, which causes the inner ring negative electrode of the battery cell 2 to short-circuit with the second housing cover 302 or the positive electrode tab 202, posing a safety risk.

[0060] In this embodiment, a second insulating member 4 is provided on the positive electrode tab 202 and the lower protrusion 3021. The second insulating member 4 covers the side of the positive electrode tab 202 away from the shell cover 3 and is connected to the lower protrusion 3021. This can prevent the negative electrode plate 205 of the inner ring of the cell 2 from short-circuiting with the lower protrusion 3021 and the positive electrode tab 202. Furthermore, after the insulating member is removed from the end face of the cell 2, the absorption of electrolyte by the cell 2 can be improved during the electrolyte injection process, thereby increasing the amount of electrolyte injected (CPK).

[0061] The insulating adhesive on the end face of the battery cell 2 in the prior art was compared with the insulating adhesive on the positive electrode tab 202 and the lower protrusion 3021 in this embodiment. The test results are shown in Table 1 below.

[0062] Table 1

[0063] Short circuit rate after cell assembly CPK injection volume Existing technology 3.19％ 1.13 This embodiment 0％ 1.41

[0064] As shown in Table 1, this embodiment reduces the short-circuit rate by 3.19% and increases the injection volume CPK to 1.41 compared to the prior art, demonstrating significant effects.

[0065] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery, characterized in that, include: The housing (1) has an open receiving cavity; A battery cell (2) is disposed in the receiving cavity. The battery cell (2) has a positive electrode tab (202) and a negative electrode tab (201). The negative electrode tab (201) is connected to the housing (1). A cover (3) is provided at the opening. The cover (3) includes a first cover (301), a second cover (302), and a first insulating member (303). The first cover (301) is connected to the housing (1). The first insulating member (303) is located between the first cover (301) and the second cover (302). The first cover (301) has a first through hole (3011). The first insulating member (303) has a second through hole (3031) corresponding to the first through hole (3011). The positive electrode tab (202) includes a connecting part (2021) connected to the battery cell (2) and an extension part (2022) connected to the second cover (302). The second insulating member (4) covers the side of the extension (2022) of the positive electrode tab (202) away from the cover (3) and contacts the second cover (302).

2. The battery according to claim 1, characterized in that, The second cover (302) is located on the side of the first cover (301) away from the battery cell (2). The second cover (302) has a lower protrusion (3021) protruding toward the side where the battery cell (2) is located, and a portion of the lower protrusion (3021) is located inside the first through hole (3011); or, the second cover (302) is located on the side of the first cover (301) close to the battery cell (2). The second cover (302) includes an upper protrusion (3022) protruding toward the side of the first cover (301), and a portion of the upper protrusion (3022) is located inside the first through hole (3011).

3. The battery according to claim 2, characterized in that, The second cover (302) has a lower protrusion (3021), on which a liquid injection hole (30211) is provided. The second insulating member (4) has a third through hole (401) corresponding to the liquid injection hole (30211), and the diameter of the third through hole (401) is larger than the diameter of the liquid injection hole (30211). And / or, the outer radius R1 of the second insulating member (4) is less than or equal to the length L of the extension (2022).

4. The battery according to claim 1, characterized in that, The cell (2) has a fourth through hole (206) corresponding to the first through hole (3011), and the second insulating member (4) has a third through hole (401) corresponding to the fourth through hole (206). The diameter of the third through hole (401) is smaller than the diameter of the fourth through hole (206), and / or, in the thickness direction of the battery, the projection of the third through hole (401) is located within the projection of the fourth through hole (206).

5. The battery according to any one of claims 2 to 3, characterized in that, The second cover (302) has a lower protrusion (3021), and the outer diameter D1 of the second insulating member (4) is greater than the diameter D3 of the lower protrusion (3021) and smaller than the outer diameter D2 of the first cover (301).

6. The battery according to any one of claims 1 to 4, characterized in that, A third insulating member (5) is provided on the lower surface of the first cover (301), and the projection of the third insulating member (5) on the lower surface of the first cover (301) at least partially overlaps with the projection of the second insulating member (4) on the lower surface of the first cover (301).

7. The battery according to claim 6, characterized in that, The edge of the third insulating member (5) extends beyond the edge of the second insulating member (4).

8. The battery according to any one of claims 1 to 4, characterized in that, The positive electrode tab (202) is provided with a protective member on the side facing the connection between the first cover (301) and the housing (1).

9. The battery according to claim 8, characterized in that, The projection of the protective member on the lower surface of the first cover (301) at least partially overlaps with the projection of the second insulating member (4) on the lower surface of the first cover (301).

10. The battery according to claim 3, characterized in that, A sealing member (6) is provided on the side of the lower protrusion (3021) away from the battery cell (2), and the sealing member (6) seals the liquid injection hole (30211).

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