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 priority to a Chinese patent application with application number 202222673198.2 filed with the China Patent Office on October 11, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of battery technology, for example, battery covers and power batteries. [Background technology]

[0003] The battery includes a housing, a core pack with tabs, and a cover plate, and the core pack is accommodated in a storage space formed by the housing and the cover plate. During assembly, the core pack is accommodated in the housing, the tabs are flattened by ultrasonic welding, and laser welded to the cover plate of the battery to be one piece. The cover plate is then fixed to the housing, and the tabs are folded to be between the cover plate and the cells, maximizing the utilization of the internal space. However, there is a problem that the shaped area of ​​the tabs is inserted upside down into the core pack when the cover is closed, which may result in a short circuit. Summary of the Invention [Means for solving the problem]

[0004] The present application provides a battery cover and a power battery, which solves the problem of the tab shaped area being inserted upside down into the core pack, thereby avoiding short circuits and improving the safety and reliability of the power battery. In the first aspect, the battery cover provided in the embodiment of the present application includes: a top cover assembly for fixedly connecting to a housing, the housing and the top cover assembly defining an accommodating space for accommodating a core pack, the top cover assembly for welding to a tab of the core pack; The insulating bracket is received in the receiving space, the insulating bracket defining a storage chamber for storing the top cover assembly and the tab, the insulating bracket having a notch through which the tab passes. In one example, the top cover assembly is removably connected to the isolation bracket. In one example, the insulating bracket includes two bracket bodies, each of which is connected to the top cover assembly, and the notch is formed between the two bracket bodies. In one example, the cutout is provided with an R-chamfered portion or a C-chamfered portion along the thickness direction of the insulating bracket.

[0005] In one example, the tab has a weld mark that is covered with an insulating adhesive. In one example, the storage chamber is a cavity having a rectangular parallelepiped shape. In one example, the tab is bent into a Z-shape and is disposed in the chamber. In one example, the insulating bracket abuts against the core pack. In one example, the insulating bracket has a through hole communicating with the storage chamber. In one example, the core pack is covered with a protective film; and / or the exterior of the housing is covered with a protective film; and / or The tab has a protective adhesive applied to it.

[0006] In one example, the top cover assembly comprises: a cover plate fixedly connected to the housing; an upper plastic and a lower plastic secured to opposite sides of the cover plate, the lower plastic being connected to the insulating bracket; a pole extending 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 provided with a groove, and the lower plastic and the insulating bracket form a containment chamber. In one example, the notch is located opposite a lower block of the pole end.

[0007] In a second aspect, the power battery provided in the embodiment of the present application includes a housing, a core pack, and the battery cover, wherein the core pack and the insulating bracket are accommodated in an accommodation space, and a 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 power battery provided by the present application, the core pack and the insulating bracket are accommodated in the accommodation space, the tab of the core pack is welded to the top cover assembly, and the tab is accommodated in the storage chamber, which provides a space for the tab to occupy, thereby preventing the core pack from scattering between the core pack and the top cover assembly, and improving the structural stability. The insulating bracket effectively isolates the tab from the core pack, thereby solving the problem of the core pack being inserted upside down due to the shaping of the tab, and thus avoiding short circuits, thereby improving the safety reliability and yield of the power battery. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a front view showing a power battery according to a specific embodiment of the present application. [Diagram 2] FIG. 2 is a side view of FIG. [Diagram 3] FIG. 2 is a schematic diagram showing the structure of a battery cover according to a specific embodiment of the present application. [Figure 4] FIG. 4 is a bottom view of FIG. 3. [Diagram 5] 5 is a cross-sectional view taken along line A-A in FIG. [Figure 6] FIG. 13 is an exploded view of the battery cover from another perspective. [Figure 7] FIG. 13 is an exploded view of the battery cover from another perspective. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0011] In this application, unless expressly specified and limited otherwise, a second feature being "above" or "below" a first feature includes the case where the first feature and the second feature are in direct contact with each other, and also includes the case where the first feature and the second feature are not in direct contact with each other, but are in contact with each other through another feature between them. In addition, a first feature being "above," "upper," or "on the upper surface" of a second feature includes the case where the first feature is directly above or diagonally above the second feature, or simply the first feature is higher in the horizontal direction than the second feature. A first feature being "below," "below," or "on the lower surface" of a second feature includes the case where the first feature is directly below or diagonally below the second feature, or simply the first feature is lower in the horizontal direction than the second feature.

[0012] As shown in Figures 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 form an accommodation space for accommodating the core pack 4, and the top cover assembly 1 is used for welding to a 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 form an accommodation chamber P for accommodating the tab 41, and the insulating bracket 2 is provided with a notch 23 through which the tab 41 passes.

[0013] When the above battery cover is used in a 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 accommodated in the accommodation chamber P, which provides a space occupied by the tab 41, and the tab 41 can be prevented from scattering between the core pack 4 and the top cover assembly 1, and the stability of the structure is good. The insulating bracket 2 effectively isolates the tab 41 from the core pack 4, thereby solving the problem that the shaping area of ​​the tab 41 is inserted upside down into the core pack 4, which is caused by the shaping of the tab 41, and thus a short circuit can be avoided, and the safety reliability and yield of the power battery are improved.

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

[0015] In one embodiment, as shown in FIG. 3 and FIG. 7, the top cover assembly 1 includes a cover plate 11, an upper plastic 12, a lower plastic 13, and a pole 14, and the cover plate 11 is fixedly connected to the housing 3. The upper plastic 12 and the lower plastic 13 are fixed to both sides of the cover plate 11, respectively, and the lower plastic 13 is connected to the insulating bracket 2. The pole 14 penetrates 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 the arrangement of the upper plastic 12 and the lower plastic 13 prevents short circuit. In addition, the pole 14 is provided with a lower block 141 on the side facing the core pack 4, and the cross-sectional area of ​​the lower block 141 is relatively large, so that the connection area with the tab 41 is increased and the reliability of the structure is improved. In one embodiment, the notch 23 is arranged opposite the lower block 141 at the end of the pole 14, so that the notch 23 can be easily passed after the tab 41 and the lower block 141 are welded. In one embodiment, the lower plastic 13 is provided with a groove 132, and the lower plastic 13 and the insulating bracket 2 form a storage chamber P. In another embodiment, the insulating bracket 2 may be provided with a groove 132 to form the storage chamber P. In another embodiment, the lower plastic 13 and the insulating bracket may be provided with a groove 132 to form the storage chamber P. There is no limitation because the arrangement is specific 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, the lower plastic 13 is not left in the area of ​​the lower block 141. In one embodiment, the storage chamber P is a cavity in the shape of a rectangular parallelepiped, which increases the storage space and makes it convenient to arrange the tab 41. For example, the length of the notch 23 = the width of the tab 41 + 2 to 5 mm, and the depth of the notch 23 = the thickness of the tab 41 + 1 to 2 mm.

[0016] 6, the notch 23 is provided with an R-chamfered portion or a C-chamfered portion 231 along the thickness direction of the insulating bracket 2, so that burrs are generated in the notch 23 and the tab 41 of the core pack 4 is prevented from being scratched by the burrs in applications where high-intensity vibration occurs. For example, the dimension of the R-chamfered portion or the C-chamfered portion 231 may be, but is not limited to, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, or 1.0 mm.

[0017] In one embodiment, in order to maximize the energy density within the range in which the tabs 41 can be accommodated, the height of the lower plastic 13 is determined according to the thickness of the shaped tabs 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 = number of layers of the tabs 41 * foil thickness * 3 * correction factor, when used to store the positive electrode tab 41, the correction factor of the height of the lower plastic 13 is adjusted in the range of 1.5 to 2.5, and when used to store the negative electrode tab 41, the correction factor of the height of the lower plastic 13 is adjusted in the range of 1.2 to 2.0.

[0018] In one embodiment, as shown in FIG. 6 and FIG. 7, the top cover assembly 1 and the insulating bracket 2 are detachably connected, so that the insulating bracket 2 can be prevented from falling off during the assembly of the core pack 4, and the stability and reliability of the connection can be improved and the installation and removal can be facilitated. 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, a nesting hole 131 is provided in the lower plastic 13, a nesting piece 24 is provided in the insulating bracket 2, and the nesting piece 24 is engaged in the nesting hole 131. In another embodiment, the insulating bracket 2 can be provided with a nesting hole 131, and the nesting piece 24 can be provided in the lower plastic 13, but is not limited thereto. For example, a plurality of sets of nesting holes 131 and nesting pieces 24 are provided, and the number of the nesting holes 131 and the nesting pieces 24 can be, but is not limited thereto, 4, 6, 8, and the like, 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 seal ring, which is disposed between the pole 14 and the cover plate 11, to ensure the hermeticity of the container space while avoiding short circuits.

[0020] In one embodiment, as shown in FIG. 3, the top cover assembly 1 is provided with an injection hole 17, and after the housing 3 and the battery cover are assembled, the electrolyte is injected into the receiving space through the injection hole 17. The electrolyte is a passage for ion migration. For example, the top cover assembly 1 further includes a seal 5 for sealing the injection hole 17 to prevent leakage of the electrolyte. For example, the seal 5 includes sealing rubber particles and a sealing aluminum sheet, and the sealing rubber particles are aligned with the injection hole 17 and filled into the injection hole 17, thereby enhancing the sealing effect of the core pack 4. The sealing aluminum sheet is used to weld and seal the injection hole 17.

[0021] In one embodiment, as shown in FIG. 3, the top cover assembly 1 further includes an insulating plate 16, which is provided on the side of the upper plastic 12 away from the cover plate 11, thereby improving the reliability of the structure.

[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, and the number of press spot welding spots may be, but is not limited to, 6EA, 8EA, 10EA, and the number of press spot welding spots is symmetrically distributed. In one embodiment, 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 being short-circuited due to an external connection.

[0023] In one embodiment, the core pack 4 is covered with a protective film. The exterior of the housing 3 is covered with a protective film to provide an insulating effect. The core pack 4 to which the positive and negative electrode tabs 41 are ultrasonically welded is covered all around with a protective film to prevent the core pack 4 from being scratched when inserted into the housing. The inner protective film is a polymer material having insulating properties, high temperature resistance, and electrolyte corrosion resistance, and may be, but is not limited to, a PET material having adhesive properties on one side.

[0024] In one embodiment, a protective adhesive is applied to the tab 41 to provide an insulating design, which can effectively prevent a short circuit between the tab 41 and the aluminum housing 3. The core pack 4 with the protective film applied has an adhesive tape applied to the tab 41, the width of the adhesive tape extends beyond the width of the tab 41 by 2-10 mm, 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 welded area. The protective adhesive of the tab 41 can ensure that the part of the cell placed in the housing that is in close contact with the aluminum housing is completely insulated.

[0025] The tabs 41 of the core pack 4 are laser welded to the corresponding top cover. The length and width of the welding wire are designed according to the overcurrent capacity required for the cell, so as to meet the power requirements of the cell. After the tabs 41 and the top cover are welded, the welded area is insulated by dispensing or pasting, and the width of the insulating adhesive layer or insulating adhesive tape should completely cover the tabs 41, and the length should completely cover the tabs 41 and the laser welded area.

[0026] In one embodiment, the core pack 4 is provided with positive and negative tabs 41, and includes positive and negative active materials, positive and negative current collectors, and a separator. The active materials are the solid-state reaction interfaces where the electrochemical reactions of the battery occur and provide the electron channels for the movement of electrons after gaining / losing electrons from the current collectors, and the separator isolates the electrons and allows the passage of ions.

[0027] In one embodiment, the tab 41 is provided with a weld mark. Specifically, the tab 41 is flattened by spur tooth ultrasonic welding, and the flat tooth ultrasonic welding has a larger and smoother weld mark area than other deep tooth welding. The flattened tab 41 and the lower electrode plate of the top cover are welded by laser welding, thereby strengthening the weld strength between the tab 41 and the top cover assembly 1, improving the overcurrent capability of the battery, and increasing the reliability of the weld. The tabs 41 of each layer are all welded, and the size of the weld mark corresponds to the size of the welding wire when laser welding the tab 41 and the cover plate 11. The size of the ultrasonic flat welding may be, but is not limited to, 10mm*20mm, 15mm*20mm, or 10mm*30mm. The number of the weld marks may be, but is not limited to, 1EA, 2EA, or 3EA. If the area of ​​the weld mark allows, only one weld mark is used as much as possible. The number of the core packs 4 may be, but is not limited to, 1EA, 2EA, or 3EA, and usually the number of the core packs 4 of the blade battery does not exceed 2EA.

[0028] Since the insulating bracket 2 is installed after the tabs 41 are bent and shaped, it is advantageous for the insulating bracket 2 to effectively fix the shaped tabs 41 to the storage chamber P of the insulating bracket 2 and the lower plastic 13. In one embodiment, as shown in Fig. 2, the tabs 41 are bent in a Z-shape and placed in the storage chamber P, so that the tabs 41 are gathered together, and it is convenient to insert the shaped tabs 41 into the storage chamber P when installing the bracket.

[0029] In one embodiment, the insulating bracket 2 abuts against the core pack 4 to fix the core pack 4, thereby preventing the core pack 4 from shaking and improving reliability.

[0030] In one embodiment, as shown in FIG. 4, the insulating bracket 2 includes two bracket bodies, each of which is 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 bracket body to form the notch 23 between the two bracket bodies, or a recess may be provided in both bracket bodies to form the notch 23 between the two bracket bodies. Both bracket bodies are detachably connected to the lower plastic 13, improving the reliability of the connection. 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 different, and accordingly, the position where the notch 23 is formed will be offset. However, the arrangement may be made according to the actual situation, and is not limited thereto. The arrangement may be made 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 with sufficient hardness, resistance to electrolyte corrosion and high temperature resistance, and is not limited to PP material, and its thickness is not limited to 0.5mm, 1.0mm, 1.5mm, 2.0mm, 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, and the shape of the through hole 25 is not limited to a circle or a square, and the design of the through hole 25 is favorable 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, which includes a first step of homogenizing the positive and negative electrodes, i.e., uniformly dispersing the positive and negative active materials together with a conductive agent and an adhesive in a solvent at a specific mass ratio; a second step of applying the positive and negative electrodes, i.e., stably applying the uniformly dispersed positive and negative electrode slurry to the positive and negative electrode current collectors; a third step of preparing the positive and negative electrode sheets, i.e., rolling the applied positive and negative electrode plates to a predetermined thickness and cutting them to a predetermined size; and a fourth step of winding (or stacking) assembly, i.e., winding (or stacking) the completed positive and negative electrode plates to form the core pack 4. the fifth step, baking, i.e., baking the assembled battery in a vacuum oven to a predetermined moisture content; the sixth step, injection, i.e., injecting electrolyte into the battery and leaving it until the electrolyte completely permeates the plates; the seventh step, formation, i.e., forming and activating the battery, and pumping the negative pressure to exhaust gas generated by side reactions in the battery; and the eighth step, capacity classification, i.e., sealing and welding the formed battery and classifying the capacity in a predetermined manner.

[0033] This embodiment provides an assembly process for a power battery, S1, ultrasonic welding of tabs 41. That is, the positive and negative tabs 41 of the core pack 4 are respectively welded by a spur welding process. S2, covering the core pack 4 with a protective film. S3, apply protective adhesive to positive and negative electrode tabs 41. S4: Weld the tab 41 and the top cover together, and apply adhesive (either the positive electrode tab 41 or the negative electrode tab 41). S5: Bend and shape the tab 41. That is, the welded tab 41 is bent and shaped in a "Z" shape. S6: Installation of the insulating bracket 2. That is, the first bracket 21 and the second bracket 22 of the insulating bracket 2 are sequentially engaged with the lower plastic 13, and 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: Insert the core pack 4 into the housing. That is, insert the core pack 4 with the insulating bracket 2 attached into the housing 3. S8: Close the top cover assembly 1 and perform press spot welding. That is, close the top cover and the corresponding housing 3, and perform press spot welding with a laser to fix the housing 3 to the cover plate 11. S9, the tab 41 and the cover plate 11 are welded together, adhesive is applied, and the tab 41 on the opposite side of the core pack 4 is laser welded to the corresponding top cover assembly 1, and adhesive is applied to the weld mark so as to completely cover the weld mark and the tab 41. S10: Bend and shape the tab 41. That is, the welded tab 41 is bent and shaped in a "Z" shape 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 sequentially engaged with the lower plastic 13, the insert 24 of the insulating bracket 2 is completely fitted into the insert hole 131 of the lower plastic 13, and the shaping region of the tab 41 is completely inserted into the storage chamber P consisting of the insulating bracket 2 and the lower plastic 13, thereby completely isolating the tab 41 and the core pack 4. S12: Close the top cover assembly 1 and perform press spot welding. That is, close the cover plate 11 and the corresponding housing 3, and perform press spot welding with a laser to fix the cover plate 11 to the housing 3, and the number of spots is the same as that of the press spot welding of the cover plate 11 described above. S13: Completely weld the cover plates 11. That is, the positive and negative cover plates 11 of the cell and the housing 3 are welded by laser welding, and the welded areas are completely sealed. [Explanation of symbols]

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

Claims

1. a top cover assembly (1) used for fixed connection with a housing (3), the top cover assembly (1) and the housing (3) forming an accommodation space for accommodating a core pack (4), the top cover assembly (1) used for welding to a tab (41) of the core pack (4); an insulating bracket (2) to be accommodated in the accommodation space, the insulating bracket (2) and the top cover assembly (1) forming a storage chamber (P) for storing the tab (41), the insulating bracket (2) having a notch (23) through which the tab (41) passes; Including, The top cover assembly (1) comprises: a cover plate (11) fixedly connected to the housing (3); an upper plastic (12) and a lower plastic (13) fixed to both sides of the cover plate (11), the lower plastic (13) being engaged and connected to the insulating bracket (2); a pole (14) extending through the upper plastic (12), the cover plate (11) and the lower plastic (13) and welded to the tab (41); The lower plastic (13) is provided with a recess (132), and the insulating bracket (2) is covered on the lower plastic (13), so that the lower plastic (13) and the insulating bracket (2) form the storage chamber (P); Height of the lower plastic (13) = Number of layers of the tab (41) * foil thickness * 3 * correction factor; When the storage chamber (P) is used to store a positive electrode tab, the correction coefficient is 1.5 to 2.5, and when the storage chamber (P) is used to store a negative electrode tab, the correction coefficient is 1.2 to 2.

0. Battery cover.

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

2. The battery cover according to claim 1.

3. The insulating bracket (2) includes two bracket bodies, each of which is connected to the top cover assembly (1), and the notch (23) is formed between the two bracket bodies.

2. The battery cover according to claim 1.

4. The notch (23) is provided with an R-chamfered portion or a C-chamfered portion (231) along the thickness direction of the insulating bracket (2).

2. The battery cover according to claim 1.

5. The tab (41) has a weld mark covered with insulating adhesive.

2. The battery cover according to claim 1.

6. The storage chamber (P) is a cavity having a rectangular parallelepiped shape.

2. 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).

2. The battery cover according to claim 1.

8. The insulating bracket (2) is in contact with the core pack (4).

2. 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).

2. The battery cover according to claim 1.

10. said core pack (4) being covered with a protective film; and / or The exterior of the housing (3) is covered with a protective film, and / or The tab (41) is provided with a protective adhesive.

2. The battery cover according to claim 1.

11. The notch (23) is disposed opposite the lower block (141) at the end of the pole (14).

2. The battery cover according to claim 1.

12. The battery cover includes 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 an insulating bracket (2) are accommodated in an accommodation space, a tab (41) of the core pack (4) is welded to a top cover assembly (1), and the tab (41) is stored in a storage chamber (P). Power battery.

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