Battery cover and power battery

Abstract

The battery cover and power battery disclosed in the present application belong to the field of battery technology. The battery cover includes a top cover assembly and an insulating bracket, the top cover assembly is used for fixed connection with a housing, the housing and the top cover assembly form an accommodation space for accommodating a core pack, the top cover assembly is used for welding to a tab of the core pack, the insulating bracket is accommodated in the accommodation space, the insulating bracket and the top cover assembly form an accommodation chamber for accommodating the tab, and the insulating bracket is provided with a notch through which the tab penetrates. The battery cover and power battery of the present application solve the problem that the shaped area of ​​the tab is inserted upside down into the core pack, and can avoid short circuits, improving the safety and reliability of the power battery.

Description

Technical Field

[0001] This application claims the priority of the Chinese patent application with the application number 202222673198.2 filed with the Chinese Patent Office on October 11, 2022, and all the contents of the said application are incorporated into this application by reference.

[0002] This application relates to the technical field of batteries, for example, battery covers and power batteries.

Background Art

[0003] The battery includes a housing, a core pack with tabs, and a cover plate. The core pack is stored in the accommodation space formed by the housing and the cover plate. When assembling, the core pack is stored in the housing, the tabs are flattened by ultrasonic welding, and welded to the battery cover plate by laser to become an integral body. Then, the cover plate is fixed to the housing, and the tabs are bent and provided between the cover plate and the cell, thereby maximizing the utilization rate of the internal space. However, when closing the cover, there is a problem that the tab shaping area is inserted upside down into the core pack, which may cause a short circuit.

Summary of the Invention

Means for Solving the Problems

[0004] This application provides a battery cover and a power battery, which solve the problem that the tab shaping area is inserted upside down into the core pack, thus avoiding short circuits and improving the safety and reliability of the power battery. In the first aspect, the battery cover provided by the embodiment of this application is a top cover assembly used for fixed connection with the housing, wherein the housing and the top cover assembly form an accommodation space for accommodating the core pack, and the top cover assembly used for welding with the tabs of the core pack, An insulating bracket housed in the accommodation space, which forms an accommodation chamber for housing the top cover assembly and the tab, and has a notch through which the tab penetrates. In one example, the top cover assembly is detachably connected to the insulating bracket. In one example, the insulating bracket includes two bracket bodies, the two bracket bodies are respectively connected to the top cover assembly, and the notch is formed between the two bracket bodies. In one example, the notch is provided with an R chamfer or a C chamfer along the thickness direction of the insulating bracket.

[0005] In one example, the tab is provided with a weld mark covered with an insulating adhesive. In one example, the accommodation chamber is a rectangular parallelepiped-shaped cavity. In one example, the tab is bent in a Z shape and is provided in the accommodation chamber. In one example, the insulating bracket is in contact with the core pack. In one example, the insulating bracket is provided with a through hole communicating with the accommodation chamber. In one example, the core pack is covered with a protective film, and / or The outside of the housing is covered with a protective film, and / or A protective adhesive is attached to the tab.

[0006] In one example, the top cover assembly A cover plate fixedly connected to the housing, Upper plastic and lower plastic fixed on both sides of the cover plate, and the lower plastic is the upper plastic and lower plastic connected to the insulating bracket, A pole penetrating through the upper plastic, the cover plate, and the lower plastic and welded to the tab. In one example, the lower plastic and / or the insulating bracket are / is provided with Recessed portion which forms a storage chamber with the lower plastic and the insulating bracket. In one example, the notch is disposed opposite to the lower block at the pole end.

[0007] In a second aspect, the power battery provided by the embodiments of the present application includes a housing, a core pack, and the battery cover. The core pack and the insulating bracket are accommodated in an accommodation space. The tab of the core pack is welded to the top cover assembly, and the tab is stored in a storage chamber.

[0008] In the battery cover and the power battery provided by the present application, the core pack and the insulating bracket are accommodated in an accommodation space, the tab of the core pack is welded to the top cover assembly, the tab is stored in a storage chamber, and the storage chamber provides the space occupied by the tab, which can avoid scattering between the core pack and the top cover assembly, and the structural stability is improved. The insulating bracket effectively isolates the tab from the core pack, solves the problem of reverse insertion into the core pack caused by the shaping of the tab, can avoid short circuits, and improves the safety and reliability and yield of the power battery.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] In the description of the present application, unless otherwise clearly specified and limited, the terms "coupling", "connection", and "fixing" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection, and may be a mechanical or electrical connection, a direct connection, an indirect connection through a medium, or an internal communication between two elements or an interaction relationship between two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to specific situations.

[0011] In the present application, unless otherwise clearly specified and limited, the second feature being "above" or "below" the first feature includes the case where the first feature and the second feature are in direct contact, and also includes the case where the first feature and the second feature are not in direct contact and are in contact through another feature therebetween. Further, the first feature being "above", "upper", or "upper surface" of the second feature includes the case where the first feature is directly above or obliquely above the second feature, or simply that the first feature has a higher horizontal height than the second feature. The first feature being "below", "lower", or "lower surface" of the second feature includes the case where the first feature is directly below or obliquely below the second feature, or simply that the first feature has a lower horizontal height than the second feature.

[0012] As shown in FIGS. 1 to 5, the power battery provided in this embodiment includes a housing 3, a core pack 4, and a battery cover. This embodiment further provides a battery cover, which includes a top cover assembly 1 and an insulating bracket 2. The top cover assembly 1 is used for fixed connection with the housing 3. The housing 3 and the top cover assembly 1 constitute an accommodation space for accommodating the core pack 4, and the top cover assembly 1 is used for welding with the tab 41 of the core pack 4. The insulating bracket 2 is accommodated in the accommodation space. The insulating bracket 2 and the top cover assembly 1 constitute a storage chamber P for storing the tab 41, and the insulating bracket 2 is provided with a notch 23 through which the tab 41 penetrates.

[0013] When the above battery cover is used in the power battery, the core pack 4 and the insulating bracket 2 are accommodated in the accommodation space. The tab 41 of the core pack 4 is welded to the top cover assembly 1, and the tab 41 is stored in the storage chamber P. The storage chamber P provides the space occupied by the tab 41, and it can avoid the scattering of the tab 41 between the core pack 4 and the top cover assembly 1, and the structural stability is improved. By effectively isolating the tab 41 and the core pack 4, the insulating bracket 2 solves the problem that the shaping area of the tab 41 caused by the shaping of the tab 41 is inserted into the core pack 4 upside down, can avoid short circuits, and improves the safety and reliability and yield of the power battery.

[0014] In one aspect, the power battery is a blade battery. In another aspect, the power battery may be other batteries without limitation.

[0015] In one aspect, as shown in FIGS. 3 and 7, the top cover assembly 1 includes a cover plate 11, an upper plastic 12, a lower plastic 13, and a pole 14. The cover plate 11 is fixedly connected to the housing 3. The upper plastic 12 and the lower plastic 13 are respectively fixed to both sides of the cover plate 11, and the lower plastic 13 is connected to the insulating bracket 2. The pole 14 penetrates through the lower plastic 13, the cover plate 11, and the upper plastic 12 and is welded to the tab 41. The cover plate 11 is usually an aluminum plate, and short - circuits are prevented by arranging the upper plastic 12 and the lower plastic 13. Further, the pole 14 is provided with a lower block 141 on the side facing the core pack 4. Since the cross - sectional area of the lower block 141 is relatively large, the connection area with the tab 41 is increased, and the reliability of the structure is improved. In one aspect, the notch 23 is arranged opposite to the lower block 141 at the end of the pole 14, so that the notch 23 can easily pass through after the tab 41 and the lower block 141 are welded. In one aspect, Recessed portion 132 is provided on the lower plastic 13, and the lower plastic 13 and the insulating bracket 2 constitute the storage chamber P. In another aspect, 132 may be provided on the insulating bracket 2 so as to constitute the storage chamber P. Recessed portion In another aspect, 132 may be provided on either the lower plastic 13 or the insulating bracket so as to constitute the storage chamber P. It is not limited because it is specifically arranged according to the actual situation. For example, in order to avoid the lower plastic 13 affecting the welding of the lower block 141 and the tab 41, no lower plastic 13 is left in the area of the lower block 141. In one aspect, the storage chamber P is a rectangular parallelepiped - shaped cavity, which increases the storage space and facilitates the arrangement of the tab 41. For example, the length of the notch 23 = the width of the tab 41+2 - 5 mm, and the depth of the notch 23 = the thickness of the tab 41+1 - 2 mm. Recessed portion

[0016] In one aspect, as shown in FIG. 6, since the notch 23 is provided with an R chamfer or a C chamfer 231 along the thickness direction of the insulating bracket 2, burrs are generated on the notch 23, and it is possible to avoid the tab 41 of the core pack 4 being damaged by the burrs in an application scenario with high strength and vibration. For example, the dimensions of the R chamfer or the C chamfer 231 may be 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm or 1.0 mm, but are not limited thereto.

[0017] In one aspect, in order to increase the energy density as much as possible within the range where the tab 41 can be accommodated, the height of the lower plastic 13 is determined according to the thickness of the shaped tab 41 to be accommodated, and the size of the storage chamber P is set according to the actual situation. For example, the height of the lower plastic 13 = the number of layers of the tab 41 * the thickness of the foil * 3 * the correction coefficient. When used for storing the positive tab 41, the correction coefficient of the height of the lower plastic 13 is adjusted in the range of 1.5 to 2.5. When used for storing the negative tab 41, the correction coefficient of the height of the lower plastic 13 is adjusted in the range of 1.2 to 2.0.

[0018] In one aspect, as shown in FIGS. 6 and 7, the top cover assembly 1 and the insulating bracket 2 are detachably connected, so that it is possible to avoid the insulating bracket 2 falling off during the assembly of the core pack 4, improve the stability and reliability of the connection, and make the detachment and attachment convenient. For example, the insulating bracket 2 is covered by the lower plastic 13, and the insulating bracket 2 and the lower plastic 13 are engaged and connected. In this embodiment, the lower plastic 13 is provided with a nesting hole 131, the insulating bracket 2 is provided with a nesting member 24, and the nesting member 24 is engaged with the nesting hole 131. In another embodiment, the insulating bracket 2 may be provided with a nesting hole 131, and the lower plastic 13 may be provided with a nesting member 24, and is not limited thereto. For example, a plurality of sets of nesting holes 131 and nesting members 24 may be provided, and the number may be 4, 6, or 8, but is not limited thereto, as long as they are symmetrically distributed on both sides of the lower plastic 13 and the insulating bracket 2.

[0019] For example, the top cover assembly 1 further includes an insulating sealing ring, and by being provided between the pole 14 and the cover plate 11, it is possible to avoid short - circuits while ensuring the sealing performance of the accommodation space.

[0020] In one aspect, as shown in FIG. 3, the top cover assembly 1 is provided with an injection hole 17. After the housing 3 and the battery cover are assembled, the electrolyte is injected into the accommodation space through the injection hole 17. The electrolyte is a path for ion movement. For example, to prevent leakage of the electrolyte, the top cover assembly 1 further includes a seal 5 for sealing the injection hole 17. For example, the seal 5 includes sealing rubber particles and a sealing aluminum sheet. By packing the sealing rubber particles into the injection hole 17 according to the injection hole 17, the sealing effect of the core pack 4 is enhanced. The sealing aluminum sheet is used to weld and seal the injection hole 17.

[0021] In one aspect, as shown in FIG. 3, the top cover assembly 1 further includes an insulating plate 16. By providing the insulating plate 16 on the side away from the cover plate 11 of the upper plastic 12, the reliability of the structure is improved.

[0022] For example, the housing 3 may be an aluminum housing, and the cover plate 11 may be an aluminum plate. The cover plate 11 and the housing 3 are connected by welding. The welding is performed by press - spot welding during which the number of press - spot welds may be 6EA, 8EA, 10EA, etc., but is not limited thereto, and the number of press - spot welds is symmetrically distributed. In one aspect, the top cover assembly 1 further includes an insulating cover 15 attached to the cover plate 11 to prevent the pole 14 and the cover plate 11 from short - circuiting due to external connection.

[0023] In one aspect, the core pack 4 is covered by a protective film. Coating the outside of the housing 3 with the protective film provides an insulating effect. The core pack 4 with the positive and negative tabs 41 ultrasonically welded is covered around by the protective film, preventing the core pack 4 from being scratched when placed in the housing. The inner protective film is a polymer material having insulation properties, high temperature resistance, and electrolyte corrosion resistance, and may be a PET member having adhesiveness on one side, but is not limited thereto.

[0024] In one aspect, by attaching a protective adhesive to the tab 41 for insulation design, a short circuit between the tab 41 and the aluminum housing 3 can be effectively avoided. For the core pack 4 with the protective film attached, an adhesive tape is attached to the tab 41, the width of the adhesive tape protrudes 2 - 10 mm from the width of the tab 41, the length of the adhesive tape covering the core pack 4 is 5 - 25 mm, and the adhesive tape covering the tab 41 is 0 - 5 mm away from the welding mark area. The protective adhesive of the tab 41 can ensure that the part of the cell placed in the housing in close contact with the aluminum housing is completely insulated.

[0025] The tab 41 of the core pack 4 is laser welded to the corresponding top cover. The length and width of the welding wire are designed according to the overcurrent capacity required by the cell, satisfying the power requirements of the cell. After the tab 41 and the top cover are welded, insulation treatment is performed in the area of the welding mark by dispensing or pasting. The width of the insulating adhesive layer or insulating adhesive tape should completely cover the tab 41, and the length should completely cover the tab 41 and the laser welding mark.

[0026] In one aspect, the core pack 4 is provided with positive and negative tabs 41, and the core pack 4 includes positive and negative electrode active materials, positive and negative electrode current collectors, and a separator. The active material is the solid-phase reaction interface where the electrochemical reaction of the battery occurs. After acquiring / losing the electrons of the current collector, it provides an electron channel for the movement of electrons. The separator isolates the electrons and allows the passage of ions.

[0027] In one aspect, the tab 41 is provided with a welding mark. Specifically, the tab 41 is flattened by flat-tooth ultrasonic welding. Compared with other deep-tooth weldings, the flat-tooth ultrasonic welding has a larger and smoother welding mark area. By welding the flattened tab 41 and the lower pole plate of the top cover by laser welding, the welding strength between the tab 41 and the top cover assembly 1 is enhanced, the overcurrent capacity of the battery is improved, and the welding reliability is increased. Each layer of the tab 41 is welded, and the size of the welding mark corresponds to the size of the welding wire when the tab 41 and the cover plate 11 are laser welded. The dimensions of the ultrasonic flat welding may be 10mm*20mm, 15mm*20mm, or 10mm*30mm, but are not limited thereto. The number of welding marks may be 1EA, 2EA, 3EA, but is not limited thereto. When the area of the welding mark permits, use only one welding mark as much as possible. The number of the core packs 4 may be 1EA, 2EA, 3EA, but is not limited thereto. Usually, the number of the core packs 4 of the blade battery does not exceed 2EA.

[0028] Since the insulating bracket 2 is attached after the tab 41 is bent and shaped, it is advantageous for the insulating bracket 2 to effectively fix the shaped tab 41 in the storage chamber P of the insulating bracket 2 and the lower plastic 13. In one aspect, as shown in FIG. 2, by bending the tab 41 in a Z shape and providing it in the storage chamber P, the tabs 41 are gathered and converged, and when attaching the bracket, it is convenient to load the shaped tab 41 into the storage chamber P.

[0029] In one aspect, the insulating bracket 2 abuts against the core pack 4 to fix the core pack 4, so that the core pack 4 does not shake and the reliability is improved.

[0030] In one aspect, as shown in FIG. 4, the insulating bracket 2 includes two bracket bodies. The two bracket bodies are respectively connected to the top cover assembly 1, and a notch 23 is formed between the two bracket bodies. A recess may be provided in only one of the bracket bodies to form the notch 23 between the two bracket bodies, or recesses may be provided in both of the two bracket bodies to form the notch 23 between the two bracket bodies. Since both of the two bracket bodies are detachably connected to the lower plastic 13, the reliability of the connection is improved. The first bracket 21 and the second bracket 22 may be arranged to distinguish the two bracket bodies, and the sizes of the first bracket 21 and the second bracket 22 may be made different. Accordingly, an offset occurs in the position where the notch 23 is formed. It should be arranged according to the actual situation and is not limited thereto. It may be arranged according to the position when the tab 41 converges and is not limited thereto. For example, the first bracket 21 and the second bracket 22 may be made of the same material or different materials.

[0031] For example, the insulating bracket 2 is made of a material having sufficient hardness, has electrolyte corrosion resistance and high temperature resistance, and is not limited to the PP material. Its thickness is not limited to 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, and the height of the upper bracket corresponds to the height of the lower plastic 13. For example, as shown in FIG. 4, the insulating bracket 2 is provided with a through hole 25 communicating with the storage chamber P. The shape of the through hole 25 is not limited to circular or square, and the design of the through hole 25 is advantageous for the free flow of the electrolyte in the internal space of the cell.

[0032] This embodiment provides a manufacturing process for the core pack 4, including the first step of homogenizing the positive and negative electrodes, that is, dispersing each of the positive and negative electrode active materials uniformly in a solvent at a specific mass ratio together with a conductive agent and an adhesive; the second step of coating the positive and negative electrodes, that is, stably coating the uniformly dispersed positive and negative electrode slurries on the current collectors of the positive and negative electrodes; the third step of creating the positive and negative electrode sheets, that is, rolling the coated positive and negative electrode plates to a predetermined thickness and cutting them to a predetermined size; the fourth step of winding (or laminating) assembly, that is, winding (or laminating) the completed positive and negative electrode plates to form and assemble the core pack 4; the fifth step of baking, that is, baking the assembled battery in a vacuum oven to a predetermined moisture content; the sixth step of injection, that is, injecting the electrolyte into the battery and leaving it until the electrolyte completely penetrates the electrode plates; the seventh step of formation, activating the battery by formation and pumping negative pressure to discharge the gas generated by side reactions in the battery; and the eighth step of capacity classification, that is, performing hermetic welding on the battery after formation and classifying the capacity in a predetermined flow.

[0033] This embodiment provides an assembly process for a power battery. S1. Ultrasonic welding of the tabs 41. That is, welding the positive and negative tabs 41 of the core pack 4 respectively by a flat tooth welding process. S2. Coating the core pack 4 with a protective film. S3. Attaching a protective adhesive to the positive and negative tabs 41. S4. Welding the tab 41 and the top cover and attaching an adhesive (either from the positive tab 41 or the negative tab 41 is acceptable). S5. Bending and shaping of the tab 41. That is, performing a "Z" - shaped bending and shaping on the welded tab 41. S6. Installation of the insulating bracket 2. That is, the first bracket 21 and the second bracket 22 of the insulating bracket 2 are engaged with the lower plastic 13 in sequence, the shaping area of the tab 41 is completely inserted into the cavity formed by the upper and lower brackets and the lower plastic 13, and the tab 41 and the core pack 4 are completely isolated. S7. Place the core pack 4 into the housing. That is, the core pack 4 with the insulating bracket 2 attached is placed into the housing 3. S8. Close the top cover assembly 1 and perform press-spot welding. That is, the top cover and the corresponding housing 3 are closed, and press-spot welding is performed with a laser to fix the housing 3 to the cover plate 11. S9. Weld the tab 41 and the cover plate 11, apply an adhesive, laser-weld the tab 41 on the opposite side of the core pack 4 to the corresponding top cover assembly 1, and apply an adhesive to the welding mark to completely cover the welding mark and the tab 41. S10. Bend and shape the tab 41. That is, perform a "Z"-shaped bending and shaping on the welded tab 41 to converge the tab 41. S11. Installation of the insulating bracket 2. That is, the first bracket 21 and the second bracket 22 of the insulating bracket 2 are engaged with the lower plastic 13 in sequence, the nested part 24 of the insulating bracket 2 is completely fitted into the nesting hole 131 of the lower plastic 13, and the shaping area of the tab 41 is completely inserted into the storage chamber P formed by the insulating bracket 2 and the lower plastic 13, so as to completely isolate the tab 41 and the core pack 4. S12. Close the top cover assembly 1 and perform press-spot welding. That is, the cover plate 11 and the corresponding housing 3 are closed, and press-spot welding is performed with a laser to fix the cover plate 11 to the housing 3. Note that the number of spots is the same as that of the press-spot welding of the above cover plate 11. S13. Completely weld the cover plate 11. That is, laser-weld the cover plates 11 of the positive and negative electrodes of the cell and the housing 3 to completely seal the welding area.

Explanation of symbols

[0034] 1 top cover assembly, 11 cover plate, 12 upper plastic, 13 lower plastic, 131 nested hole, 132 Recessed portion , 14 pole, 141 lower block, 15 insulating cover, 16 insulating plate, 17 injection hole, 2 insulating bracket, 21 first bracket, 22 second bracket, 23 notch, 231 C chamfer, 24 insert, 25 through hole, 3 housing, 4 core pack, 41 tab, 5 seal, P storage chamber.

Claims

1. A top cover assembly (1) used for a fixed connection with a housing (3), wherein the top cover assembly (1) and the housing (3) form an accommodation space for accommodating a core pack (4), and the top cover assembly (1) used for welding with a tab (41) of the core pack (4), An insulating bracket (2) accommodated in the accommodation space, wherein the insulating bracket (2) and the top cover assembly (1) form a storage chamber (P) for storing the tab (41), and the insulating bracket (2) provided with a notch (23) through which the tab (41) penetrates, comprising, The top cover assembly (1) A cover plate (11) fixedly connected to the housing (3), Upper plastic (12) and lower plastic (13) fixed to both sides of the cover plate (11), wherein the lower plastic (13) is engaged and connected to the insulating bracket (2), the upper plastic (12) and the lower plastic (13), The upper plastic (12), the cover plate (11), and the lower plastic (13) are provided with a pole (14) that penetrates through and is welded to the tab (41), The lower plastic (13) is provided with a recess (132), the insulating bracket (2) is covered on the lower plastic (13), and the lower plastic (13) and the insulating bracket (2) form the storage chamber (P), The height of the lower plastic (13) = the number of layers of the tab (41) * the thickness of the foil * 3 * correction factor, When the storage chamber (P) is used for storing the positive tab, the correction factor is 1.5 to 2.5, and when the storage chamber (P) is used for storing the negative tab, the correction factor is 1.2 to 2.0, Battery cover.

2. The top cover assembly (1) is detachably connected to the insulating bracket (2). The battery cover according to Claim 1.

3. The insulating bracket (2) includes two bracket bodies, the two bracket bodies are respectively connected to the top cover assembly (1), and the notch (23) is formed between the two bracket bodies. The battery cover according to Claim 1.

4. The notch (23) is provided with an R chamfer or a C chamfer (231) along the thickness direction of the insulating bracket (2). The battery cover according to claim 1.

5. The tab (41) is provided with a welding mark covered with an insulating adhesive. The battery cover according to claim 1.

6. The storage chamber (P) is a rectangular parallelepiped-shaped cavity. The battery cover according to claim 1.

7. The tab (41) is bent in a Z shape and is provided in the storage chamber (P). The battery cover according to claim 1.

8. The insulating bracket (2) is in contact with the core pack (4). The battery cover according to claim 1.

9. The insulating bracket (2) is provided with a through hole (25) communicating with the storage chamber (P). The battery cover according to claim 1.

10. The core pack (4) is covered with a protective film, and / or The outside of the housing (3) is covered with a protective film, and / or A protective adhesive is attached to the tab (41). The battery cover according to claim 1.

11. The notch (23) is arranged to face the lower block (141) at the end of the pole (14). The battery cover according to claim 1.

12. A housing (3), a core pack (4), and the battery cover according to any one of claims 1 to 11, wherein the core pack (4) and the insulating bracket (2) are accommodated in an accommodation space, the tab (41) of the core pack (4) is welded to the top cover assembly (1), and the tab (41) is stored in the storage chamber (P). Power battery.

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