Injection-molded cover plate, battery cell and battery pack

Abstract

An injection-molded cover plate, a battery cell and a battery pack. The injection-molded cover plate comprises: a cover plate body (10) connected to terminal posts (20), wherein the cover plate body (10) is provided with an expansion zone (11) and a non-expansion zone (12); a preset size of the cover plate body (10) in a first direction (D1) is A0, and a preset size thereof in a second direction (D2) is B0; injection-molded members (30) are arranged between the cover plate body (10) and the terminal posts (20); before the injection-molded members (30) are assembled, the size of the expansion zone (11) in the first direction (D1) is A, where A=A0-1 / [(10-16)t2] mm; and / or the size of the expansion zone (11) in the second direction (D2) is B, where B=B0-1 / [(10-16)t1] mm. After the cover plate body (10) and the terminal posts (20) are assembled by means of injection molding, the expansion zone (11) expands until the size of the expansion zone (11) is highly consistent with the size of the non-expansion zone (12), such that it is ensured that the shape and size precision of the cover plate body (10) after injection molding meets design requirements, thereby improving the size consistency and yield of the injection-molded cover plate.

Description

Injection molded cover, battery cell and battery pack

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application with application number 202410108737.9 and title “Injection molded cover, battery cell and battery pack” filed with the China Patent Office on January 26, 2024, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to an injection-molded cover plate, a battery cell, and a battery pack. Background Art

[0004] Lithium-ion batteries have become the most widely used secondary batteries due to their high energy density, excellent cycle performance, high operating voltage, and lack of memory effect. They are widely used as power batteries in electric vehicles and energy storage applications, leading to increasing demands for their performance and safety. The lithium battery cover is a critical component in lithium-ion batteries. Its function is to weld to the battery shell to form a sealed cavity, preventing electrolyte leakage and potentially safety accidents. The cover also stabilizes the internal pressure of the battery and protects against external interference.

[0005] At present, the injection-molded cover mainly consists of three parts: a bare aluminum plate, a lower plastic, and a pole. The assembly method is to position the bare aluminum sheet, the pole, and the lower plastic, and then perform injection molding between the pole and the bare aluminum sheet to fix their relative positions. However, when the pole is close to the edge of the cover, due to the influence of injection molding expansion, the length and width of the bare aluminum sheet are partially enlarged after the pole and the bare aluminum sheet are fixed by injection molding, which makes it difficult to assemble the cover and the shell, thereby affecting the yield rate of the battery cell and the production efficiency and quality of the battery pack.

[0006] Application Contents

[0007] In view of this, the purpose of this application includes providing an injection-molded cover plate, battery cell and battery pack, so as to solve to a certain extent the technical problem that the pole of the injection-molded cover plate is close to the edge of the cover plate in the prior art, and due to the influence of injection molding material expansion, the pole and the bare aluminum sheet are locally enlarged in length and width after injection molding and fixation, which makes it difficult to assemble the cover plate and the shell, and further affects the yield of the battery cell and the production efficiency and quality of the battery pack.

[0008] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present application are as follows:

[0009] The present application provides an injection-molded cover plate, comprising:

[0010] pole;

[0011] A cover plate body is connected to the pole, and a material expansion area and a non-material expansion area are formed on the cover plate body; a preset size of the cover plate body in the first direction is A0, in mm, and a preset size in the second direction is B0, in mm;

[0012] An injection molded part, disposed between the cover plate body and the pole;

[0013] Before the injection molded part is assembled, the size of the swelling area in the first direction is A, A=A0-1 / [(10~16)t2]mm, t2 is the distance between the injection molded part and the edge of the cover plate body in the first direction; and / or, the size of the swelling area in the second direction is B, B=B0-1 / [(10~16)t1]mm, t1 is the distance between the injection molded part and the edge of the cover plate body in the second direction; t1 is 1.5mm to 15mm; and / or, t2 is 2mm to 20mm.

[0014] In the above technical solution, further, the material expansion area in the first direction and / or the non-material expansion area in the second direction are formed into a symmetrical structure.

[0015] In any of the above technical solutions, further, the cover plate body is formed into a strip structure extending along the first direction.

[0016] In any of the above technical solutions, further, at least one material expansion zone is provided. When a plurality of material expansion zones are provided, the plurality of material expansion zones are arranged at intervals along the first direction.

[0017] In any of the above technical solutions, further, the length dimension of the cover plate body is (40+X)±(0.03-0.08) mm, and X≥0.

[0018] In any of the above technical solutions, further, the width dimension of the cover plate body is (11+Y)±(0.03-0.08) mm, and Y≥0.

[0019] In any of the above technical solutions, further, at least one pole is provided.

[0020] In any of the above technical solutions, further, when a plurality of poles are provided, the non-material expansion area is provided between two adjacent poles.

[0021] In any of the above technical solutions, further, along the first direction or along the second direction, the total size of the non-material expansion area is not less than the total size of the material expansion area.

[0022] In any of the above technical solutions, further, the injection molded part is formed into a closed annular structure to cover the circumferential side wall of the pole.

[0023] In any of the above technical solutions, further, the injection molded cover plate further includes:

[0024] A pressure relief member is provided in the non-material expansion area in the first direction.

[0025] In any of the above technical solutions, further, the injection molded cover plate further includes:

[0026] The liquid injection hole passes through the cover plate body, and the liquid injection hole is arranged in the non-material expansion area in the first direction.

[0027] The present application also provides a battery cell formed by assembling the injection molded cover plate in any of the above technical solutions.

[0028] The present application also provides a battery pack comprising the above-mentioned battery cells assembled.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] The injection molded cover provided in this application includes:

[0031] pole;

[0032] A cover plate body is connected to the pole, and a material expansion area and a non-material expansion area are formed on the cover plate body; a preset size of the cover plate body in the first direction is A0, in mm, and a preset size in the second direction is B0, in mm;

[0033] An injection molded part, disposed between the cover plate body and the pole;

[0034] Before the injection molded part is assembled, the size of the swelling area in the first direction is A, A=A0-1 / [(10~16)t2]mm, t2 is the distance between the injection molded part and the edge of the cover plate body in the first direction; and / or, the size of the swelling area in the second direction is B, B=B0-1 / [(10~16)t1]mm, t1 is the distance between the injection molded part and the edge of the cover plate body in the second direction; t1 is 1.5mm to 15mm; and / or, t2 is 2mm to 20mm.

[0035] The injection-molded cover provided in the present application optimizes the shape of the cover body, and sets a swelling area and a non-swelling area on the cover body. In the first direction and the second direction, the size of the swelling area is smaller than the size of the non-swelling area, so that after the cover body and the pole are injection-molded and assembled, the swelling area expands to a size that is highly consistent with the size of the non-swelling area, thereby ensuring that the shape accuracy and dimensional accuracy of the injection-molded cover after injection molding meet the design requirements, reducing the risk of dimensional deviation of the injection-molded cover, and improving the dimensional consistency and yield of the injection-molded cover, thereby ensuring that the injection-molded cover and the shell are convenient and reliable to assemble, thereby ensuring the yield of the battery cell and the assembly efficiency and quality of the battery pack.

[0036] The battery cell provided in the present application includes the above-mentioned injection-molded cover plate, and therefore has all the beneficial effects of the above-mentioned injection-molded cover plate, which will not be repeated here.

[0037] The battery pack provided in the present application includes the above-mentioned battery cells, and therefore has all the beneficial effects of the above-mentioned battery cells, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0039] FIG1 is a cross-sectional view of the structure of an injection-molded cover plate provided in an embodiment of the present invention;

[0040] FIG2 is a schematic structural diagram of an injection molded cover plate provided in an embodiment of the present invention;

[0041] 3 is a schematic diagram showing the distribution structure of the material expansion area and the non-material expansion area in the cover plate body in the first direction of the injection molded cover plate provided by an embodiment of the present invention;

[0042] 4 is a schematic diagram of the distribution structure of the material expansion area and the non-material expansion area in the cover plate body in the second direction of the injection-molded cover plate provided by an embodiment of the present invention;

[0043] FIG5 is a schematic diagram showing the positions of t1 and t2 on the cover plate body of the injection-molded cover plate provided by an embodiment of the present invention;

[0044] FIG6 is a schematic structural diagram of a positive electrode cover plate in another structure of an injection-molded cover plate provided in an embodiment of the present invention;

[0045] FIG7 is a schematic structural diagram of a negative electrode cover plate in another structure of an injection-molded cover plate provided in an embodiment of the present invention.

[0046] Figure numerals: 10 - cover body; 11 - material expansion area; 12 - non-material expansion area; 101 - positive electrode cover; 102 - negative electrode cover; 20 - pole; 21 - positive pole; 22 - negative pole; 30 - injection molded part; 40 - pressure relief part; 50 - liquid injection hole; 60 - lower plastic; D1 - first direction; D2 - second direction. DETAILED DESCRIPTION

[0047] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0048] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application.

[0049] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of this application.

[0050] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0052] The following describes the injection-molded cover plate, battery cell, and battery pack according to the embodiments of the present application with reference to FIG1 to FIG7 .

[0053] The pole 20 is connected to the cover body 10, and the injection molded part 30 is arranged between the cover body 10 and the pole 20. The injection molded part 30 is formed by an injection molding process. The injection molded part 30 is formed into a closed annular structure to cover the circumferential side wall of the pole 20, thereby ensuring a reliable connection between the pole 20 and the cover body 10.

[0054] A swelling area 11 and a non-swelling area 12 are formed on the cover body 10. The injection molded part 30 can expand the size of the swelling area 11 in the first direction D1 and / or the second direction D2, so that after the injection molded cover is assembled, the size of the swelling area 11 in the first direction D1 and / or the second direction D2 is increased compared to before assembly.

[0055] The preset size of the cover body 10 in the first direction D1 is A0, in mm, and the preset size in the second direction D2 is B0, in mm, where the preset sizes A0 and B0 are the design sizes of the cover body 10, that is, the sizes required for smooth assembly with the battery cell shell; before the injection molded part 30 is assembled between the pole 20 and the cover body 10, the size of the expansion area 11 in the first direction D1 is A, A=A0-1 / [(10~16)t2]mm, where t2 is the distance between the injection molded part 30 and the edge of the cover body 10 in the first direction. distance; and / or, the size of the swelling area 11 in the second direction D2 is B, B = B0-1 / [(10~16)t1] mm, wherein t1 is the distance between the edge of the injection molded part 30 and the cover body 10 in the second direction, so that after the cover body 10 and the pole 20 are injection molded and assembled, the swelling area 11 expands to a size that is highly consistent with the size of the non-swelling area 12, thereby ensuring that the shape accuracy and dimensional accuracy of the injection molded cover after injection molding meet the design requirements, reducing the risk of dimensional deviation of the injection molded cover, and improving the consistency and yield of the dimensional quality of the injection molded cover.

[0056] Preferably, t1 is 1.5 mm to 15 mm, and / or t2 is 2 mm to 20 mm. When t1 and / or t2 are within the above-defined ranges, the parameters calculated using the limiting conditions of A = A0-1 / [(10-16)t2] mm and / or B = B0-1 / [(10-16)t1] mm can ensure that the shape accuracy and dimensional accuracy of the injection-molded cover plate after injection molding meet the design requirements.

[0057] It should be noted that the expansion of the cover body 10 after assembly is related to the distance from the edge of the injection molded part 30 to the edge of the cover body 10. The smaller the distance, the more serious the expansion. In addition, as shown in Figure 5, the distances t1 and t2 between the edges of the injection molded part 30 and the cover body 10 are the shortest distances from the injection molded part 30 to the long side or short side of the cover body 10, respectively.

[0058] Preferably, when the two conditions of A=A0-1 / [(10-16)t2]mm and B=B0-1 / [(10-16)t1]mm are satisfied at the same time, the overall precision of the injection molded cover plate is the highest.

[0059] It should be noted that the division method of the material expansion area 11 and the non-material expansion area 12 is to determine whether there is a large size difference compared to the preset size A0 or B0 during measurement only along the first direction D1 or along the second direction D2. The areas divided in Figures 3 and 4 cannot be combined and defined.

[0060] It should be further explained that, preferably, the first direction D1 is perpendicular to the second direction D2 , the first direction D1 is the length direction of the cover body 10 , and the second direction D2 is the width direction of the cover body 10 .

[0061] Preferably, the length dimension of the cover body 10 (i.e., the dimension in the first direction D1) is: (40+X)±(0.03~0.08) mm, X≥0; the width dimension of the cover body 10 (i.e., the dimension in the second direction D2) is: (11+Y)±(0.03~0.08) mm, Y≥0, wherein the length dimension of the cover body 10 corresponds to the preset dimension A0, and the width dimension of the cover body 10 corresponds to the preset dimension B0, thereby limiting the parameter range of the above-mentioned preset dimensions A0 and B0, thereby improving the reliability of the above-mentioned limiting conditions of A=A0-1 / [(10~16)t2]mm and / or B=B0-1 / [(10~16)t1]mm, and further ensuring that the shape accuracy and dimensional accuracy of the injection molded cover after injection molding meet the design requirements. In order to prove the validity and reliability of the limiting conditions of A=A0-1 / [(10~16)t2]mm and / or B=B0-1 / [(10~16)t1]mm, the verification test is as follows:

[0062] Preferably, two poles 20 are provided on the cover body 10 and are spaced apart along the first direction D1. The injection molded parts 30 are arranged in one-to-one correspondence with the poles 20. Two expansion areas 11 are also correspondingly provided. The actual measured size of one expansion area 11 in the second direction D2 is B1, and the actual measured size of the other expansion area 11 in the second direction D2 is B2. The non-expansion area 12 is arranged between the two expansion areas 11, and its actual measured size in the second direction D2 is B3.

[0063] In Test 1, B0 is 35±0.05 mm, t1=2 mm, and B=B0-1 / [(10-16)×2] mm. Test 1 is compared with examples in the prior art (Comparative Example 1 and Comparative Example 2) in which the width of the cover plate is abnormal due to the injection molding of the pole 20 and the bare aluminum sheet. The parameters B1, B2, and B3 in the comparative examples with abnormal width are measured in the same manner as the parameters B1, B2, and B3 in Test 1. The test results are shown in Table 1:

[0064] Table 1 Dimensional parameters of B1, B2 and B3 in the second direction D2 before and after injection molding

[0065] In the second test, B0 is 35±0.05 mm, t1=3.5 mm, and B=B0-1 / [(10-16)×3.5] mm. The second test is compared with the examples in the prior art (Comparative Examples 3 and 4) in which the width of the cover plate is abnormal due to the injection molding of the pole 20 and the bare aluminum sheet. The parameters B1, B2, and B3 in the comparative examples with abnormal width are measured in the same manner as the parameters B1, B2, and B3 in the second test. The test results are shown in Table 2:

[0066] Table 2 Dimensional parameters of B1, B2 and B3 in the second direction D2 before and after injection molding

[0067] In Test 3, B0 is 35±0.05 mm, t1=5 mm, and B=B0-1 / [(10-16)×5] mm. Test 3 is compared with examples in the prior art (Comparative Examples 5 and 6) in which the width of the cover plate is abnormal due to the injection molding of the pole 20 and the bare aluminum sheet. The parameters B1, B2, and B3 in the comparative examples with abnormal width are measured in the same manner as the parameters B1, B2, and B3 in Test 3. The test results are shown in Table 3:

[0068] Table 3 Dimensional parameters of B1, B2 and B3 in the second direction D2 before and after injection molding

[0069] Referring to Table 1, Table 2 and Table 3, it can be seen that in Test 1, Test 2 and Test 3, B0 is within the parameter limit range of (11+Y)±(0.03~0.08)mm, Y≥0, t1 is between 1.5mm and 15mm, and the sizes of B1 and B2 before injection molding are smaller than the size of B3, while the sizes of the two swelling areas 11 after injection molding are increased, so that the sizes of B1 and B2 after injection molding are respectively close to the sizes of B3 before and after injection molding, thereby confirming that reducing the size of the swelling area 11 by 1 / [(10~16)t1]mm on the basis of the preset size B0 before injection molding can ensure the consistency of the overall width size of the cover plate body 10 after injection molding.

[0070] In Comparative Examples 1 to 6, the sizes of B1, B2 and B3 are approximately the same before injection molding, but the sizes of B1 and B2 increase after injection molding, while the size of B3 does not change after injection molding, resulting in an abnormal width of the cover plate after injection molding and fixing, making it difficult to assemble the injection molded cover plate and the battery cell shell.

[0071] Preferably, along the second direction D2, the material expansion area 11 is arranged in the middle, and the actual measured size of the material expansion area 11 in the first direction D1 is A1. The two non-material expansion areas 12 are respectively arranged on the upper and lower sides of the material expansion area 11, and the actual measured size of one of the non-material expansion areas 12 in the first direction D1 is A2, and the actual measured size of the other non-material expansion area 12 in the first direction D1 is A3.

[0072] In Test 4, A0 is 165±0.05 mm, t2=2.5 mm, and A=A0-1 / [(10-16)×2.5] mm. Test 4 is compared with examples in the prior art (Comparative Examples 7 and 8) in which the length of the cover plate is abnormal due to the injection molding of the pole 20 and the bare aluminum sheet. The parameters A1, A2, and A3 in the comparative examples with abnormal width are measured using the same method as the parameters A1, A2, and A3 in Test 4. The test results are shown in Table 4:

[0073] Table 4 Dimensional parameters of A1, A2 and A3 in the first direction D1 before and after injection molding

[0074] In Test 5, A0 is 165±0.05 mm, t2=4 mm, and A=A0-1 / [(10-16)×4] mm. Test 5 is compared with examples in the prior art (Comparative Examples 9 and 10) in which the length of the cover plate is abnormal due to the injection molding of the pole 20 and the bare aluminum sheet. The parameters A1, A2, and A3 in the comparative examples with abnormal width are measured using the same method as the parameters A1, A2, and A3 in Test 5. The test results are shown in Table 5:

[0075] Table 5 Dimensional parameters of A1, A2 and A3 in the first direction D1 before and after injection molding

[0076] In Test 6, A0 is 165±0.05 mm, t2=5.5 mm, and A=A0-1 / [(10-16)×5.5] mm. Test 6 is compared with examples in the prior art (Comparative Examples 11 and 12) in which the length of the cover plate is abnormal due to the injection molding of the pole 20 and the bare aluminum sheet. The parameters A1, A2, and A3 in the comparative examples with abnormal width are measured using the same method as the parameters A1, A2, and A3 in Test 6. The test results are shown in Table 6:

[0077] Table 6 Dimensional parameters of A1, A2 and A3 in the first direction D1 before and after injection molding

[0078] Referring to Tables 4, 5 and 6, it can be seen that in Tests 4, 5 and 6, A0 is located at (40+X)±(0.03~0.08)mm, X≥0, t2 is located between 2mm and 20mm, and the size of A1 before injection molding is smaller than the sizes of A2 and A3. After injection molding, the swelling area 11 expands under the action of the injection molded part 30, so that the size of A1 increases relative to before injection molding, and the size of A1 after injection molding is similar to the sizes of A2 and A3 before and after injection molding, thereby confirming that reducing the preset size A0 by 1 / [(10~16)t2]mm before injection molding can ensure the consistency of the overall length size of the cover plate body 10 after injection molding.

[0079] In Comparative Examples 7 to 12, the sizes of A1, A2, and A3 are approximately the same before injection molding, but the size of A1 increases after injection molding, while the sizes of A2 and A3 remain unchanged, resulting in an abnormal length of the cover plate after injection molding and fixing, making it difficult to assemble the injection molded cover plate with the battery cell shell.

[0080] In summary, Tests 1 to 6 can prove that the limiting conditions of A=A0-1 / [(10~16)t2]mm and / or B=B0-1 / [(10~16)t1]mm can ensure that the shape accuracy and dimensional accuracy of the injection molded cover plate after injection molding meet the design requirements, reduce the risk of dimensional deviation of the injection molded cover plate, and improve the consistency and yield of the injection molded cover plate size.

[0081] It should be noted that the difference in the measurement parameters of the non-expansion area 12 before and after injection molding is due to measurement errors and is unavoidable.

[0082] It should be further explained that, in the actual measurement process, the specific parameters of A1, A2 and A as well as B1, B2 and B3 can be determined by taking the average of multiple measurements.

[0083] Preferably, as shown in Figure 2, the pole 20 is located in the middle position of the cover body 10 in the first direction D1 and / or the second direction D2, so that the expansion area 11 forms a symmetrical structure in the first direction D1, and / or the non-expansion area 12 forms a symmetrical structure in the second direction D2, thereby ensuring that the injection molded part 30 evenly expands the expansion area 11, thereby further ensuring that the shape accuracy and dimensional accuracy of the injection molded cover after injection molding meet the design requirements.

[0084] Preferably, as shown in Figure 3 or Figure 4, along the first direction D1 or along the second direction D2, the total size of the non-expansion area 12 is not less than the total size of the expansion area 11, that is, in the first direction D1 or the second direction D2 of the cover body 10, there is at least one expansion area 11 and non-expansion area 12. When there are multiple expansion areas 11 and / or non-expansion areas 12, the total size of the expansion area 11 (or non-expansion area 12) is the sum of the sizes of each expansion area 11 (or non-expansion area 12) in the first direction D1 or the second direction D2. This ensures that the area of ​​the entire cover body 10 that expands and deforms after injection molding is smaller, which is conducive to ensuring the overall shape accuracy of the cover body 10 after injection molding.

[0085] Preferably, the cover body 10 is formed as a strip structure extending along the first direction D1, and at least one expanding material area 11 is provided. When multiple expanding material areas 11 are provided, the multiple expanding material areas 11 are arranged at intervals along the first direction D1. This avoids the situation where the expansion of the expanding material areas 11 affects each other when the size of the cover body 10 in the second direction D2 is small, resulting in the unreliability of the limiting conditions of A=A0-1 / [(10~16)t2]mm and / or B=B0-1 / [(10~16)t1]mm.

[0086] Preferably, at least one pole 20 is provided; when multiple poles 20 are provided, a non-expansion area 12 is provided between two adjacent poles 20, so as to avoid the two adjacent poles 20 from influencing each other when being injection molded on the cover body 10, resulting in accumulation of expansion deformation of the expansion area 11, making the limiting conditions of A=A0-1 / [(10~16)t2]mm and / or B=B0-1 / [(10~16)t1]mm unreliable.

[0087] Preferably, as shown in Figures 1 and 2, the injection molded cover plate further includes a pressure relief member 40 disposed on the cover plate body 10. When a battery cell fails and generates gas, the pressure relief member 40 promptly opens to discharge the gas within the battery cell, ensuring safe use. Preferably, the pressure relief member 40 is an explosion-proof valve mounted on the cover plate body 10, or an explosion-proof notch engraved on the cover plate body 10.

[0088] Preferably, the pressure relief member 40 is disposed in the non-expansion area 12 in the first direction D1 , so that during the injection molding process of the pole 20 and the cover body 10 , the non-expansion area 12 will not expand and deform, thereby ensuring that the performance of the pressure relief member 40 is not affected.

[0089] Preferably, the injection molded cover plate further includes an injection hole 50 extending through the cover plate body 10. An injection tube extends into the injection hole 50 to inject electrolyte into the battery cell. In a preferred embodiment, the injection hole 50 is located in the non-expansion area 12 in the first direction D1. This prevents expansion and deformation of the non-expansion area 12 during the injection molding process of the electrode 20 and the cover plate body 10, thereby ensuring that the shape and size of the injection hole 50 remain unchanged. This allows the injection tube and the injection hole 50 to be reliably assembled, thereby achieving smooth injection.

[0090] Preferably, the injection-molded cover further includes a lower plastic 60 , and the lower plastic 60 is assembled on a side of the cover body 10 facing the battery cell housing.

[0091] The pole 20 includes a positive pole and a negative pole. In the first embodiment, as shown in FIG2 , the positive pole and the negative pole are arranged on the same cover plate body 10. Thus, in the first embodiment, as shown in FIG3 , two expansion areas 11 corresponding to the two poles 20 are arranged in the first direction D1, and one non-expansion area 12 is arranged; and as shown in FIG4 , one expansion area 11 corresponding to the second direction D2 is arranged, and two non-expansion areas 12 are arranged and are respectively arranged on both sides of the expansion area 11 in the second direction D2.

[0092] Optionally, the battery cell is a blade battery cell, and the cover plate body includes a positive cover plate 101 and a negative cover plate 102, the pressure relief piece 40 is arranged on the positive cover plate 101, and the injection hole 50 is arranged on the negative cover plate 102; the positive electrode column 21 is installed on the positive cover plate 101 via the injection molded part 30, and the negative electrode column 22 is installed on the negative cover plate 102 via the injection molded part 30. Since only one electrode is provided on each cover plate body in the second embodiment, the positive cover plate 101 and the negative cover plate 102 are each provided with one material expansion area and one non-material expansion area in the length direction or the width direction.

[0093] According to an injection-molded cover plate provided by the present invention, a material expansion area and a non-material expansion area are set on the cover plate body by optimizing the shape of the cover plate body. In the first direction and the second direction, the size of the material expansion area is smaller than the size of the non-material expansion area, so that after the cover plate body and the pole are injection-molded and assembled, the material expansion area expands to a size that is highly consistent with the size of the non-material expansion area, thereby ensuring that the shape accuracy and dimensional accuracy of the injection-molded cover plate after injection molding meet the design requirements, reducing the risk of dimensional deviation of the injection-molded cover plate, and improving the dimensional consistency and yield of the injection-molded cover plate.

[0094] According to a battery cell provided by the present invention, the battery cell includes the injection molded cover plate as described above. After the injection molded cover plate is assembled, the shape accuracy and dimensional accuracy meet the design requirements, thereby ensuring that the injection molded cover plate and the shell are assembled conveniently and reliably, thereby saving assembly time, improving assembly efficiency and the yield rate of the battery cell.

[0095] According to a battery pack provided by the present invention, the battery cells described above are connected to form a battery module. Since the injection-molded cover plate does not protrude from the battery cell shell, the multiple battery cells can be stacked on each other to improve the battery pack assembly efficiency and the space utilization inside the battery pack, increase the energy density, and effectively improve the battery life of the battery pack, thereby meeting the use requirements of the battery pack.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application. Industrial Applicability

[0097] The injection-molded cover plate, battery cell and battery pack provided in the present application can ensure that after the cover plate body and the pole are injection-molded and assembled, the expansion area expands to a size that is highly consistent with the size of the non-expansion area, thereby ensuring that the shape and dimensional accuracy of the cover plate body after injection molding meet the design requirements, thereby improving the consistency and yield of the injection-molded cover plate size.

Claims

1. An injection-molded cover plate, characterized in that, The injection-molded cover plate includes: Terminal post; Cover plate body, connected to the terminal post, with a bulging area and a non-bulging area formed on the cover plate body; the preset dimension of the cover plate body in the first direction is A0, in millimeters, and the preset dimension in the second direction is B0, in millimeters; Injection-molded part, arranged between the cover plate body and the terminal post; Before the injection-molded part is assembled, the dimension of the bulging area in the first direction is A, A = A0 - 1 / [(10 - 16)t2] mm, where t2 is the distance between the injection-molded part and the edge of the cover plate body in the first direction; and / or, the dimension of the bulging area in the second direction is B, B = B0 - 1 / [(10 - 16)t1] mm, where t1 is the distance between the injection-molded part and the edge of the cover plate body in the second direction; t1 is 1.5 mm to 15 mm; and / or, t2 is 2 mm to 20 mm.

2. The injection-molded cover plate according to claim 1, characterized in that, The bulging area is formed into a symmetric structure in the first direction and / or the non-bulging area is formed into a symmetric structure in the second direction.

3. The injection-molded cover plate according to claim 1 or 2, characterized in that, The cover plate body is formed into a strip structure extending along the first direction.

4. The injection-molded cover plate according to any one of claims 1 to 3, characterized in that, There is at least one bulging area. When there are multiple bulging areas, the multiple bulging areas are arranged at intervals along the first direction.

5. The injection-molded cover plate according to any one of claims 1 to 3, characterized in that The length dimension of the cover plate body is (40 + X) ± (0.03 - 0.08) mm, X ≥ 0.

6. The injection-molded cover plate according to any one of claims 1 to 3, characterized in that, The width dimension of the cover plate body is (11 + Y) ± (0.03 - 0.08) mm, Y ≥ 0.

7. [Corrected according to Rule 91 on 03.07.2024] The injection-molded cover plate according to any one of claims 1 to 3, characterized in that, There is at least one terminal post.

8. The injection-molded cover plate according to any one of claims 7, characterized in that When there are multiple terminal posts, a non-bulging area is arranged between two adjacent terminal posts.

9. The injection-molded cover plate according to any one of claims 1 to 3, characterized in that, Along the first direction or the second direction, the total dimension of the non-bulging area is not less than the total dimension of the bulging area.

10. The injection-molded cover plate according to any one of claims 1 to 3, characterized in that, The injection-molded part is formed into a closed annular structure to wrap around the circumferential side wall of the terminal post.

11. The injection-molded cover plate according to any one of claims 1 to 3, characterized in that, The injection-molded cover plate further includes: Pressure relief part, arranged in the non-bulging area in the first direction.

12. The injection-molded cover plate according to any one of claims 1 to 3, characterized in that, The injection-molded cover plate further includes: Liquid injection hole, penetrating through the cover plate body, and the liquid injection hole is arranged in the non-bulging area in the first direction.

13. A battery cell, characterized in that, Including the injection-molded cover plate according to any one of claims 1 to 12.

14. A battery pack, characterized in that, Including the battery cell according to claim 13.

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