A battery top cover assembly and a battery cell

Abstract

The utility model relates to battery technical field especially relates to a battery top cover subassembly and battery monomer. The battery top cover subassembly includes top cover, buffer and check valve, and top cover is provided with liquid injection hole. Buffer sets up in the side of top cover to the direction of electric core. Along the axial direction of liquid injection hole, the projection of buffer and the projection of liquid injection hole at least partly overlap, and the circumferential side surface of buffer and the inner wall surface of liquid injection hole form liquid injection runner. Check valve sets up between buffer and liquid injection hole, and check valve communicates with liquid injection runner to make the one-way flow of electrolyte in liquid injection runner. The battery monomer includes above -mentioned battery top cover subassembly, and the buffer effect of electrolyte is played to buffer and direct action through buffer, avoids the direct impact of electrolyte to electric core, to avoid the diaphragm of electric core top to take place and turn over and lead to short circuit. Meanwhile, electrolyte disperses and flows along liquid injection runner, and the liquid injection efficiency is improved. In addition, check valve makes the one-way flow of electrolyte in liquid injection runner, and avoids the overflow.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery top cover assembly and a battery cell. Background Technology

[0002] In the top cover structure of lithium batteries, especially square lithium-ion batteries, the electrolyte injection hole is generally designed as a circular through hole. When adding electrolyte into the battery casing through the injection hole, the following problems usually occur: 1) The electrolyte rushes into the battery casing at high pressure, causing the separator on the top of the cell to fold. In severe cases, the cathode and anode may come into contact, resulting in a short circuit after charging; 2) The electrolyte flows into the battery casing from only one direction, resulting in low injection efficiency; 3) As energy density requirements increase, the remaining internal space of the battery casing, excluding the cell, becomes increasingly limited. It is difficult for the electrolyte to flow quickly into the bottom of the battery casing at the end of the injection, causing some electrolyte to overflow from the injection hole, resulting in leakage. Utility Model Content

[0003] The purpose of this invention is to provide a battery top cover assembly and a battery cell to prevent the separator of the battery cell from folding and causing a short circuit during the liquid injection process, while improving the liquid injection efficiency and preventing the problem of liquid overflow.

[0004] To achieve this objective, the technical solution adopted by this utility model is as follows:

[0005] A battery top cover assembly, comprising:

[0006] Top cover, wherein the top cover is provided with a liquid injection hole;

[0007] A buffer element is disposed on the side of the top cover facing the battery cell; along the axial direction of the injection hole, the projection of the buffer element at least partially overlaps with the projection of the injection hole, and an injection flow channel is formed between the circumferential side surface of the buffer element and the inner wall surface of the injection hole.

[0008] A check valve is provided between the buffer and the injection hole, and the check valve is connected to the injection channel to allow the electrolyte in the injection channel to flow out in one direction.

[0009] As an optional solution, along the axial direction of the injection hole, the check valve includes at least two valve body structures, each of which extends circumferentially along the injection hole.

[0010] The valve body structure furthest from the top cover is the lower valve body, and the valve body structure closest to the top cover is the upper valve body. A main flow channel is formed between the lower valve body and the upper valve body, and a secondary flow channel is formed between the upper valve body and the inner wall surface of the injection hole. Both the main flow channel and the secondary flow channel are connected to the injection flow channel, and the inlet direction of the main flow channel intersects with the inlet direction of the secondary flow channel.

[0011] As an optional solution, the upper valve body includes at least a first valve body and a second valve body, with the first valve body and the second valve body spaced apart along the radial direction of the injection hole;

[0012] A first flow channel is formed between the first valve body and the inner wall surface of the injection hole, and a second flow channel is formed between the second valve body and the inner wall surface of the injection hole. The inlet of the first flow channel is connected to the injection flow channel, and the outlet of the first flow channel is connected to the inlet of the second flow channel to form the secondary flow channel. The inlet of the first flow channel and the inlet of the second flow channel are also connected to the main flow channel.

[0013] As an alternative, along the axial direction of the injection hole, the upper valve body is inclined away from the top cover, and the lower valve body is inclined towards the top cover. The upper valve body and the lower valve body are inclined in opposite directions and at different angles.

[0014] As an optional configuration, the upper valve body has an inclination angle of 20°-45° and the lower valve body has an inclination angle of 5°-20° in a direction parallel to the top cover.

[0015] As an optional solution, the top cover includes an insulating component and a cover plate. The insulating component is disposed on the side of the cover plate close to the battery cell. The insulating component has a first through hole, and the cover plate has a second through hole. The second through hole communicates with the first through hole to form the liquid injection hole. The buffer component is disposed on the surface of the insulating component away from the cover plate.

[0016] The buffer includes a boss that protrudes toward the surface of the cover plate; the boss includes a guide ramp and a plane, the plane being away from the insulating member, the guide ramp being circumferentially arranged around the boss and connecting to the plane, and the liquid injection channel being formed between the guide ramp and the inner wall surface of the first through hole.

[0017] As an optional solution, the buffer also includes a bracket, and at least two brackets are provided at circumferential intervals along the boss. The two ends of the brackets are respectively connected to the guide slope and the inner wall of the first through hole, and a check valve is provided between two adjacent brackets.

[0018] As an optional embodiment, the inner wall surface of the first through hole includes a first inclined surface and a second inclined surface connected together. Both the first inclined surface and the second inclined surface are inclined along the axial direction toward the injection hole. The first inclined surface forms a first hole segment, and the second inclined surface forms a second hole segment. The plane extends into the first hole segment; and / or, the inclination angle of the first inclined surface is less than the inclination angle of the guide inclined surface, and the inclination angle of the second inclined surface is greater than the inclination angle of the guide inclined surface.

[0019] As an optional solution, the distance between the plane and the upper surface of the cover plate is 3mm-10mm.

[0020] A battery cell includes the aforementioned battery top cover assembly.

[0021] The beneficial effects of this utility model are as follows:

[0022] This invention proposes a battery top cover assembly in which the projection of a buffer element along the axial direction of the injection hole at least partially overlaps with the projection of the injection hole. An injection channel is formed between the circumferential side of the buffer element and the inner wall of the injection hole. Electrolyte entering the injection hole falls onto the buffer element and flows into the battery casing through the injection channel. This allows the buffer element to buffer and guide the electrolyte during injection, preventing direct impact of the electrolyte on the battery cells inside the casing and reducing the impact pressure of the electrolyte. This helps prevent the separator at the top of the battery cells from folding and causing a short circuit. Simultaneously, the electrolyte flows dispersedly along the injection channel, improving injection efficiency. A check valve ensures unidirectional outflow of electrolyte from the injection channel, preventing reverse flow and overflow during injection, thus improving the reliability of the injection process.

[0023] This utility model proposes a battery cell including the aforementioned battery top cover assembly. The buffer component acts as a buffer and guide during electrolyte filling, preventing the electrolyte from directly impacting the battery cell inside the battery casing, thus avoiding short circuits caused by the diaphragm at the top of the cell folding over. Simultaneously, the electrolyte flows dispersedly along the injection channel, improving injection efficiency. The check valve allows the electrolyte in the injection channel to flow out in one direction, preventing reverse flow of the electrolyte and overflow during the injection process, thereby improving the reliability of the injection process. Attached Figure Description

[0024] Figure 1 This is a top view of the battery top cover assembly provided in this embodiment of the utility model;

[0025] Figure 2 yes Figure 1 Sectional view along the middle AA direction;

[0026] Figure 3 yes Figure 2 Enlarged view of the structure at point B;

[0027] Figure 4 This is a partial top view of the battery top cover assembly provided in this embodiment of the present invention;

[0028] Figure 5 This is a partial bottom view of the battery top cover assembly provided in this embodiment of the utility model;

[0029] Figure 6This is a longitudinal sectional view of the battery top cover assembly provided in this embodiment of the utility model.

[0030] The component names and labels in the diagram are as follows:

[0031] 1. Top cover; 11. Insulating component; 110. First through hole; 111. First inclined surface; 112. Second inclined surface; 12. Cover plate;

[0032] 2. Buffer component; 21. Boss; 211. Guide ramp; 212. Plane; 22. Bracket;

[0033] 3. Check valve; 31. Lower valve body; 32. Upper valve body; 321. First valve body; 322. Second valve body; 33. Main flow channel; 34. Secondary flow channel; 341. First flow channel; 342. Second flow channel. Detailed Implementation

[0034] To make the technical problem solved by this utility model, the technical solution adopted, and the technical effect achieved clearer, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining this utility model and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this utility model are shown in the accompanying drawings, not all of them.

[0035] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0036] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0037] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0038] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0039] This embodiment proposes a battery cell, which includes a battery casing, a battery cell, and a battery top cover assembly. The battery cell is installed inside the battery casing, and the battery top cover assembly seals the opening at the top of the battery casing to ensure that the battery cell is in a sealed environment.

[0040] like Figure 1 and Figure 2 As shown, this embodiment also proposes a battery top cover assembly, which includes a top cover 1 with a liquid injection hole. Specifically, the top cover 1 includes an insulating member 11 and a cover plate 12. The insulating member 11 is disposed on the side of the cover plate 12 near the battery cell. The insulating member 11 has a first through hole 110, and the cover plate 12 has a second through hole. The second through hole communicates with the first through hole 110 to form a liquid injection hole.

[0041] When adding electrolyte into the battery casing through the injection hole, the following problems usually occur: 1) The electrolyte rushes into the battery casing at high pressure above the cell, causing the separator on the top of the cell to fold. In severe cases, the cathode and anode may come into contact, resulting in a short circuit after charging; 2) The electrolyte flows into the battery casing from only one direction, resulting in low injection efficiency; 3) As energy density requirements increase, the remaining internal space of the battery casing, excluding the cell, becomes increasingly limited. It is difficult for the electrolyte to flow quickly into the bottom of the battery casing at the end of the injection, causing some electrolyte to overflow from the injection hole, resulting in the problem of electrolyte overflow.

[0042] To solve the above problems, such as Figure 2 and Figure 3 As shown, the battery top cover assembly also includes a buffer 2 and a check valve 3. The buffer 2 is located on the side of the top cover 1 facing the battery cell. Along the axial direction of the injection hole ( Figure 3 The projection of the buffer element 2 (in the vertical direction) at least partially overlaps with the projection of the injection hole, and an injection channel is formed between the circumferential side surface of the buffer element 2 and the inner wall surface of the injection hole. A check valve 3 is disposed between the buffer element 2 and the injection hole, and the check valve 3 is connected to the injection channel to allow the electrolyte in the injection channel to flow out in one direction.

[0043] Along the axial direction of the injection hole, the projection of the buffer 2 at least partially overlaps with the projection of the injection hole. An injection channel is formed between the circumferential side of the buffer 2 and the inner wall of the injection hole. The electrolyte entering the injection hole falls onto the buffer 2 and flows into the battery casing through the injection channel. This allows the buffer 2 to act as a buffer and guide during electrolyte filling, preventing the electrolyte from directly impacting the battery cells inside the battery casing and reducing the impact pressure of the electrolyte. This helps prevent the diaphragm at the top of the battery cells from folding and causing a short circuit. Simultaneously, the electrolyte flows dispersedly along the injection channel, improving injection efficiency. A check valve 3 ensures unidirectional outflow of the electrolyte within the injection channel, preventing reverse flow of the electrolyte and overflow during the injection process, thus improving the reliability of the injection process.

[0044] Specifically, the buffer 2 is disposed on the surface of the insulating member 11 away from the cover plate 12. The buffer 2 includes a boss 21 that protrudes toward the surface of the cover plate 12. The boss 21 includes a guide ramp 211 and a plane 212. The plane 212 is away from the insulating member 11. The guide ramp 211 is arranged circumferentially around the boss 21 and connects to the plane 212. A liquid injection channel is formed between the guide ramp 211 and the inner wall surface of the first through hole 110.

[0045] In this embodiment, the boss 21 has a frustum structure. Along the axial direction of the injection hole, the boss 21 has a small end and a large end. The end face of the small end of the boss 21 is the aforementioned plane 212, and the guide slope 211 is inclined. The boss 21 is coaxially arranged with the injection hole, and the small end with the plane 212 extends into the injection hole, making the injection channel approximately annular. The guide slope 211 guides the flow of electrolyte. Since the plane 212 is the top surface of the boss 21, it blocks and withstands the impact of the electrolyte. During injection, the electrolyte first impacts the plane 212 and flows into the battery casing through the injection channel, preventing the electrolyte from directly impacting the battery cell in a columnar shape. This avoids the separator at the top of the battery cell from folding and causing a short circuit, thus improving the protection of the battery cell.

[0046] like Figure 4 and Figure 5 As shown, the buffer 2 also includes brackets 22. At least two brackets 22 are spaced apart circumferentially on the boss 21. The two ends of the brackets 22 are connected to the guide slope 211 and the inner wall of the first through hole 110, respectively. A check valve 3 is provided between each pair of adjacent brackets 22. By setting brackets 22 on the boss 21, on the one hand, the boss 21 is connected to the insulating component 11 through the brackets 22, realizing the stable installation of the buffer 2 on the top cover 1; on the other hand, by setting at least two brackets 22, the electrolyte flow channel is divided into multiple independent flow channels, so that the electrolyte can flow into the battery casing from different independent flow channels, realizing the dispersed flow of the electrolyte, avoiding the electrolyte from converging in the battery casing, further reducing the impact force of the electrolyte, and preventing the separator of the battery cell from folding and causing a short circuit.

[0047] In this embodiment, the boss 21 and the bracket 22 are integrally formed, and the bracket 22 is a rib structure on the surface of the guide slope 211. Each check valve 3 is connected to two adjacent brackets 22 at both ends along the circumference of the injection hole. The guide slope 211 has four brackets 22 protruding at equal intervals along the circumference of the boss 21 to divide the injection channel into four independent channels, so that the electrolyte flows evenly into the battery casing from four directions, realizing the uniform flow of electrolyte in multiple directions. In other embodiments, the number of brackets 22 can be two, three, or more than five, which is not specifically limited here.

[0048] like Figure 3 As shown, the inner wall surface of the first through hole 110 includes a first inclined surface 111 and a second inclined surface 112 connected together. Both the first inclined surface 111 and the second inclined surface 112 are inclined along the axial direction toward the injection hole. The first inclined surface 111 forms a first hole segment, and the second inclined surface 112 forms a second hole segment. The plane 212 extends into the first hole segment. The inclination angle of the first inclined surface 111 is smaller than the inclination angle of the guide inclined surface 211, and the inclination angle of the second inclined surface 112 is larger than the inclination angle of the guide inclined surface 211. The first inclined surface 111 and the second inclined surface 112, together with the guide inclined surface 211, form an injection channel. Since the inclination angle of the first inclined surface 111 is smaller than that of the second inclined surface 112, the cross-sectional area of ​​the injection channel gradually decreases in the first hole section and gradually increases in the second hole section along the flow direction of the electrolyte. The cross-section of the injection channel at the intersection of the first hole section and the second hole section is the smallest, and a negative pressure environment is formed here to quickly draw the electrolyte into the battery casing, thereby improving the injection efficiency.

[0049] It should be noted that, as Figure 6 As shown, the inclination angle of the first inclined surface 111 is the angle α between the first inclined surface 111 and the cover plate 12, the inclination angle of the guide inclined surface 211 is the angle between the guide inclined surface 211 and the cover plate 12, and the inclination angle of the second inclined surface 112 is the angle β between the second inclined surface 112 and the cover plate 12.

[0050] like Figure 3As shown, the distance H1 between the plane 212 and the upper surface of the cover plate 12 in this embodiment is 3mm-10mm. Specifically, the distance H1 can be 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm, etc., so that there is a suitable distance between the boss 21 and the cover plate 12, so as to balance the electrolyte injection efficiency and the size of the battery top cover assembly. If the distance H1 is too small, the distance between the plane 212 and the cover plate 12 is too close, which reduces the volume of the first through hole 110, which is not conducive to the rapid injection of electrolyte and reduces the electrolyte injection efficiency; if the distance H1 is too large, the distance between the plane 212 and the cover plate 12 is too far, which increases the height of the battery top cover assembly, thereby increasing the space occupied by the buffer 2 in the battery casing.

[0051] like Figure 3 As shown, along the axial direction of the injection hole, the check valve 3 includes at least two valve body structures, each extending circumferentially along the injection hole. The valve body structure furthest from the top cover 1 is the lower valve body 31, and the valve body structure closest to the top cover 1 is the upper valve body 32. A main flow channel 33 is formed between the lower valve body 31 and the upper valve body 32, and a secondary flow channel 34 is formed between the upper valve body 32 and the inner wall of the injection hole. Both the main flow channel 33 and the secondary flow channel 34 are connected to the injection flow channel, and the inlet direction of the main flow channel 33 intersects the inlet direction of the secondary flow channel 34.

[0052] Since most of the electrolyte in the injection hole flows from the main flow channel 33 to the battery casing, and a small portion flows from the secondary flow channel 34 to the battery casing, the electrolyte is dispersed, further reducing the impact force of the electrolyte on the battery cell. This reduces the risk of short circuit caused by separator folding. When reverse electrolyte flow occurs (i.e., electrolyte flows from the battery casing to the injection hole), the electrolyte at the inlet of the main flow channel 33 collides and impacts with the electrolyte flowing out of the inlet of the secondary flow channel 34. This impact force between the electrolytes prevents the electrolyte from flowing back out of the main flow channel 33, achieving a good anti-reverse flow effect and ensuring unidirectional flow of electrolyte within the check valve 3, thus preventing overflow.

[0053] In this embodiment, the check valve 3 includes only two valve body structures, namely, an upper valve body 32 and a lower valve body 31 arranged in a stacked manner, so that the check valve 3 has a main flow channel 33, which helps to reduce the volume and installation space of the check valve 3. In other embodiments, the check valve 3 can also be provided with a multi-layer valve body structure, such as three or four layers or more, so that the check valve 3 has multiple main flow channels 33.

[0054] like Figure 3As shown, the upper valve body 32 includes at least a first valve body 321 and a second valve body 322, which are spaced apart along the radial direction of the injection hole. A first flow channel 341 is formed between the first valve body 321 and the inner wall surface of the injection hole, and a second flow channel 342 is formed between the second valve body 322 and the inner wall surface of the injection hole. The inlet of the first flow channel 341 communicates with the injection flow channel, and the outlet of the first flow channel 341 communicates with the inlet of the second flow channel 342 to form a secondary flow channel 34. The inlets of both the first flow channel 341 and the second flow channel 342 are also connected to the main flow channel 33. The secondary flow channel 34 includes a first flow channel 341 and a second flow channel 342 that are connected. The inlet of the first flow channel 341 is also the inlet of the secondary flow channel 34, so that the inlet direction of the first flow channel 341 intersects with the inlet direction of the main flow channel 33. The inlet direction of the second flow channel 342 also intersects with the main flow channel 33. That is, the inlet of the second flow channel 342 is not parallel to the main flow channel 33. When the electrolyte flows in reverse, the electrolyte in the second flow channel 342 forms a blocking impact on the electrolyte in the main flow channel 33. Then, some electrolyte enters the first flow channel 341 and forms a blocking impact on the electrolyte at the inlet of the main flow channel 33 at the inlet of the first flow channel 341. This achieves a double blocking effect to prevent the electrolyte in the main flow channel 33 from flowing in reverse, thereby improving the backflow prevention effect of the check valve 3.

[0055] In this embodiment, the upper valve body 32 includes only a first valve body 321 and a second valve body 322, that is, two valve body structures are arranged radially at intervals along the injection hole, so that the secondary flow channel 34 forms two separate flow channels, thereby achieving double blocking impact on the electrolyte in the main flow channel 33. In other embodiments, the upper valve body 32 can also arrange more valve body structures radially at intervals along the injection hole as needed, such as three or four or more, so that the secondary flow channel 34 has multiple separate flow channels, thereby achieving multiple blocking impact on the electrolyte in the main flow channel 33, further improving the backflow prevention effect of the check valve 3.

[0056] It should be noted that, along the axial direction of the injection hole, the upper valve body 32 is inclined away from the top cover 1 (i.e., from top to bottom along the axial direction of the injection hole), while the lower valve body 31 is inclined towards the top cover 1 (from bottom to top along the axial direction of the injection hole). The inclination directions of the upper valve body 32 and the lower valve body 31 are opposite and their inclination angles are different. Specifically, both the upper valve body 32 and the lower valve body 31 are annular plates, and their longitudinal sections are approximately teardrop-shaped. The top and bottom of the upper valve body 32 gradually move away from the center of the injection hole, while the top and bottom of the lower valve body 31 gradually move closer to the center of the injection hole. When the electrolyte flows in reverse in the first flow channel 341 and the second flow channel 342, it flows from bottom to top and then from top to bottom, thus blocking the reverse flow of electrolyte in the main flow channel 33 and ensuring the backflow prevention effect of the check valve 3.

[0057] like Figure 6As shown, along the direction parallel to the top cover 1, the inclination angle of the upper valve body 32 is 20°-45°, and the inclination angle of the lower valve body 31 is 5°-20°. The inclination angle of the upper valve body 32 is the included angle α between the upper valve body 32 and the cover plate 12, and the included angle α can be 20°, 25°, 30°, 35°, 40°, or 45°, etc. The inclination angle of the lower valve body 31 is the included angle b between the lower valve body 31 and the cover plate 12, and the included angle b can specifically be 5°, 10°, 15°, or 20°, etc. Through the above arrangement, the main flow channel 33 has a suitable flow area to ensure the injection flow rate and injection efficiency of the electrolyte. If the tilt angles of the upper valve body 32 and the lower valve body 31 are both too small, the main flow channel 33 and the secondary flow channel 34 will tend to be horizontal, reducing the flow rate of the electrolyte and making it difficult to improve the electrolyte injection efficiency. If the tilt angles of the upper valve body 32 and the lower valve body 31 are both too large, the space occupied by the upper valve body 32 and the lower valve body 31 will be increased, that is, the height of the battery top cover assembly will be increased, thereby increasing the overall height and volume of the battery cell.

[0058] The above embodiments merely illustrate the basic principles and characteristics of this utility model. This utility model is not limited to the above embodiments. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A battery top cover assembly, characterized in that, include: Top cover (1), the top cover (1) is provided with a liquid injection hole; A buffer (2) is disposed on the side of the top cover (1) facing the battery cell; along the axial direction of the injection hole, the projection of the buffer (2) overlaps at least partially with the projection of the injection hole, and an injection flow channel is formed between the circumferential side surface of the buffer (2) and the inner wall surface of the injection hole. Check valve (3) is provided between the buffer (2) and the injection hole. The check valve (3) is connected to the injection channel so that the electrolyte in the injection channel flows out in one direction.

2. The battery top cover assembly according to claim 1, characterized in that, Along the axial direction of the injection hole, the check valve (3) includes at least two valve body structures, each of which extends circumferentially along the injection hole. The valve body structure away from the top cover (1) is the lower valve body (31), and the valve body structure close to the top cover (1) is the upper valve body (32). A main flow channel (33) is formed between the lower valve body (31) and the upper valve body (32), and a secondary flow channel (34) is formed between the upper valve body (32) and the inner wall surface of the injection hole. Both the main flow channel (33) and the secondary flow channel (34) are connected to the injection flow channel, and the inlet direction of the main flow channel (33) intersects with the inlet direction of the secondary flow channel (34).

3. The battery top cover assembly according to claim 2, characterized in that, The upper valve body (32) includes at least a first valve body (321) and a second valve body (322), and the first valve body (321) and the second valve body (322) are spaced apart along the radial direction of the injection hole; A first flow channel (341) is formed between the first valve body (321) and the inner wall surface of the injection hole, and a second flow channel (342) is formed between the second valve body (322) and the inner wall surface of the injection hole. The inlet of the first flow channel (341) is connected to the injection flow channel, and the outlet of the first flow channel (341) is connected to the inlet of the second flow channel (342) to form the secondary flow channel (34). The inlets of the first flow channel (341) and the second flow channel (342) are also connected to the main flow channel (33).

4. The battery top cover assembly according to claim 2, characterized in that, Along the axial direction of the injection hole, the upper valve body (32) is inclined away from the top cover (1), and the lower valve body (31) is inclined towards the top cover (1). The upper valve body (32) and the lower valve body (31) are inclined in opposite directions and at different angles.

5. The battery top cover assembly according to claim 4, characterized in that, Along the direction parallel to the top cover (1), the upper valve body (32) has an inclination angle of 20°-45°, and the lower valve body (31) has an inclination angle of 5°-20°.

6. The battery top cover assembly according to any one of claims 1-5, characterized in that, The top cover (1) includes an insulating component (11) and a cover plate (12). The insulating component (11) is disposed on the side of the cover plate (12) close to the battery cell. The insulating component (11) is provided with a first through hole (110). The cover plate (12) is provided with a second through hole. The second through hole communicates with the first through hole (110) to form the liquid injection hole. The buffer component (2) is disposed on the surface of the insulating component (11) away from the cover plate (12). The buffer (2) includes a boss (21) that protrudes toward the surface of the cover plate (12); the boss (21) includes a guide slope (211) and a plane (212) that is away from the insulating member (11); the guide slope (211) is arranged around the circumference of the boss (21) and connects to the plane (212); the guide slope (211) and the inner wall surface of the first through hole (110) form the liquid injection channel.

7. The battery top cover assembly according to claim 6, characterized in that, The buffer (2) also includes a bracket (22). The boss (21) is provided with at least two brackets (22) spaced apart in the circumferential direction. The two ends of the bracket (22) are respectively connected to the inner wall surface of the guide slope (211) and the first through hole (110). The check valve (3) is provided between two adjacent brackets (22).

8. The battery top cover assembly according to claim 6, characterized in that, The inner wall surface of the first through hole (110) includes a first inclined surface (111) and a second inclined surface (112) connected together. The first inclined surface (111) and the second inclined surface (112) are both inclined along the axial direction toward the injection hole. The first inclined surface (111) forms a first hole segment, and the second inclined surface (112) forms a second hole segment. The plane (212) extends into the first hole segment. And / or, the inclination angle of the first inclined surface (111) is smaller than the inclination angle of the guide inclined surface (211), and the inclination angle of the second inclined surface (112) is larger than the inclination angle of the guide inclined surface (211).

9. The battery top cover assembly according to claim 6, characterized in that, The distance between the plane (212) and the upper surface of the cover plate (12) is 3mm-10mm.

10. A single battery cell, characterized in that, Includes the battery top cover assembly according to any one of claims 1-9.

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