Battery cell
By setting up holes and protruding parts on the plastic parts, and using laser melting to form a blocking part, the protection film welding quality in lithium -ion batteries is difficult to control and difficulty in equipment maintenance, and stable connection and efficient production have been achieved.
Patent Information
- Application Number
- CN202420445085.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-07
- Publication Date
- 2025-01-28
- Estimated Expiration
- 2034-03-07
AI Technical Summary
The welding quality of the protective film in existing lithium-ion batteries is difficult to control, and the equipment is difficult to maintain, which affects product quality and production efficiency.
By setting up the hole and protruding parts on the plastic parts, and the blocking part of the part of the flip through the protruding part, the laser melting is used to form a blocking part to realize the connection between the protective film and the plastic parts to avoid direct welding.
A stable connection between the protective film and the plastic parts reduces the difficulty of welding, avoids the difficulty of welding temperature errors and equipment maintenance, and improves product quality and production efficiency.
Smart Images
Figure CN222422024U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of lithium ion batteries, in particular to a battery core. Background Art
[0002] Existing lithium-ion batteries usually include a shell, a cover plate, and a bare cell arranged in the shell. The bare cell is coated with a protective film to protect the bare cell. After the protective film is coated on the bare cell, it is usually welded to the plastic part of the cover plate to fix and constrain the protective film. At present, the welding of the protective film usually includes two methods: pulse hot melt welding and laser welding. Laser welding uses the heat generated by the focused laser beam for welding. During laser welding, the protective film and the plastic part need to fit well, but the plastic part in the cell is thin due to space, weight and other conditions, and it is difficult to withstand a large clamping force. Therefore, the laser welding of the protective film is still in the laboratory stage and is difficult to be applied on a large scale in industry. Pulse hot melt welding generates instantaneous high temperature through metal hot melt strips, so that the protective film and the plastic part are melted and connected, and there is a welding temperature error that is difficult to control, affecting product quality. At the same time, hot melt welding requires regular replacement of Teflon tape and hot melt wire, which makes it difficult to maintain welding equipment and affects product production efficiency. Utility Model Content
[0003] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a battery cell for solving the problems in the prior art of difficult control of welding quality and difficulty in equipment maintenance when welding the protective film.
[0004] In order to achieve the above-mentioned object and other related objects, the utility model provides a battery cell, comprising:
[0005] a housing having an opening,
[0006] A bare battery cell, wherein the bare battery cell is arranged in the housing,
[0007] The cover plate includes a cover plate body and a plastic part. The cover plate body is covered on the opening of the shell. The plastic part is located in the shell and between the cover plate body and the bare cell.
[0008] A protective film, the protective film covers the bare battery cell and the plastic part,
[0009] The protective film is provided with a through hole corresponding to the plastic part, and a protruding portion protruding and passing through the through hole is provided on the outer surface of the plastic part cooperating with the protective film, and a blocking portion is provided on the portion of the protruding portion passing through the through hole, and the normal direction of the connection between the outer surface of the plastic part and the protruding portion is the protruding direction of the protruding portion, and along the protruding direction of the protruding portion, the projection of the blocking portion is at least partially located outside the projection of the through hole.
[0010] Optionally, the bare cell has a pole ear, the opening of the shell is arranged corresponding to the pole ear of the bare cell, and the cover plate further includes a pole arranged on the cover plate body, and the pole ear is electrically connected to the pole.
[0011] Optionally, the bare cell has two pole ears, the two pole ears are a positive pole ear and a negative pole ear, and the positive pole ear and the negative pole ear are respectively located at two opposite ends of the bare cell.
[0012] The shell is provided with the openings corresponding to the positive electrode ear and the negative electrode ear respectively, there are two cover plates, and the two cover plates are respectively provided corresponding to the two openings of the shell, and the positive electrode ear and the negative electrode ear are respectively electrically connected to the poles corresponding to the cover plates.
[0013] Optionally, along the protruding direction of the protruding portion, a height difference between the top of the blocking portion and the plastic part is 0.3 mm to 0.79 mm.
[0014] Optionally, along the protruding direction of the protruding portion, a height difference between an edge of the cover plate body close to the protruding portion and a top of the blocking portion is 0.65 mm to 0.94 mm.
[0015] Optionally, there are multiple protrusions, and the multiple protrusions are arranged in sequence around the plastic part.
[0016] Optionally, the protective film surrounds the plastic component and the bare battery cell for at least one circle.
[0017] Optionally, the protrusion is cylindrical, and the through hole is a circular hole matching the protrusion.
[0018] Optionally, the protective film is a polyethylene terephthalate film.
[0019] Optionally, the blocking portion is connected to the protruding portion in a T shape.
[0020] Optionally, the blocking portion is formed by laser melting and then solidifying the portion of the protrusion that passes through the protective film.
[0021] As described above, the battery cell of the utility model has the following beneficial effects: since the protective film is provided with a through hole corresponding to the plastic part, a protrusion is provided on the outer surface of the plastic part and the protective film, the protrusion protrudes and passes through the through hole, and a blocking part is provided on the part of the protrusion passing through the through hole, and the normal direction of the connection between the outer surface of the plastic part and the protrusion is the protrusion direction of the protrusion, and along the protrusion direction of the protrusion, the projection of the blocking part is at least partially located outside the projection of the through hole. The normal direction of the connection between the outer surface of the plastic part and the protrusion is also the separation direction between the protective film and the plastic part, and the blocking part can block the protective film in the separation direction between the protective film and the plastic part, thereby avoiding the separation of the protective film and the plastic part, and realizing the connection between the protective film and the plastic part. The blocking part can be formed by melting the part of the protrusion passing through the protective film by laser or other methods, and then cooling and solidifying, without directly welding the protective film and the plastic part, thereby reducing the difficulty of connecting the protective film and the plastic part. At the same time, the thickness of the plastic part at the protrusion position is increased, avoiding problems such as welding through the plastic part, which is conducive to reducing the defective rate of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 The structure of the bare battery cell and the plastic part before being covered with a protective film in the embodiment of the utility model is shown in FIG. Figure 1 ;
[0023] Figure 2 The structure of the bare battery cell and the plastic part before being covered with a protective film in the embodiment of the utility model is shown in FIG. Figure 2 ;
[0024] Figure 3 It is a schematic diagram of the structure of the bare battery cell and the plastic parts after being covered with a protective film in the embodiment of the utility model;
[0025] Figure 4 It is a schematic diagram of the structure of two opposite pole ears on the bare electrode in the embodiment of the utility model;
[0026] Figure 5 This is a schematic diagram of the structure of the plastic part in the embodiment of the utility model;
[0027] Figure 6 It is a partial cross-sectional schematic diagram of the connection position between the protrusion and the protective film in the embodiment of the utility model;
[0028] Figure 7 This is a schematic diagram of the structure before a laser device is used to form a blocking portion in an embodiment of the utility model;
[0029] Figure 8 It is a schematic diagram of the structure after a blocking portion is formed by using a laser device in an embodiment of the utility model.
[0030] Description of reference numerals:
[0031] Bare battery cell 1, protective film 2, plastic part 3, cover body 4, protrusion 5, through hole 6, blocking part 7, pole 8, pole ear 9, lens pressing block 10, supporting leg 11, laser 12, and through hole 13. DETAILED DESCRIPTION
[0032] The following is a description of the implementation of the present invention by means of specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.
[0033] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the utility model, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the utility model, should still fall within the scope of the technical content disclosed by the utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the utility model. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the utility model without substantial change of the technical content.
[0034] At present, the protective film is usually connected to the plastic parts of the battery cell by welding. The specific welding methods usually include pulse hot melt welding and laser welding.
[0035] The following problems are prone to occur when using pulse hot melt welding: the temperature of hot melt welding is difficult to control with high precision, and the actual temperature error of hot melt welding is more than ±5%. If the hot melt welding temperature is too low, the hot melt tension will be insufficient after the protective film and the plastic parts are welded, and if the hot melt welding temperature is too high, it is easy to cause the protective film to be burned through, which will affect the product quality. At the same time, when using hot melt welding, the hot melt wire used for heating needs to be replaced frequently, resulting in frequent shutdowns, affecting production efficiency, and the welding position is prone to molten beads, wire drawing and other phenomena, affecting product quality. Finally, since the metal hot melt bar of hot melt welding directly acts on the protective film, it is prone to wire drawing, adhesion and other phenomena. Therefore. When performing hot melt welding, a layer of polytetrafluoroethylene (PTFE) tape is usually pasted on the hot melt bar, and it is replaced regularly according to the use effect, which makes the maintenance of hot melt welding inconvenient and reduces the hot melt effect.
[0036] The principle of laser welding is to use the heat generated by the focused laser beam to melt the material and then weld it. Directly using laser to overlap the protective film and plastic parts for laser welding, the following problems are likely to occur: When overlapping extremely thin plastic parts, more requirements are placed on the light wave performance of the plastic parts. The light wave transmittance of the upper plastic part should be good, while the light wave absorption of the lower plastic part should be good. Therefore, the laser welding effect is poor at the overlapping positions such as the side of the protective film. At the same time, when laser lap welding is used between the protective film and the plastic part, the protective film and the plastic part must be completely pressed. If there is a gap between the protective film and the plastic part, it will cause welding explosion points and affect product quality. Considering factors such as weight and volume, the thickness of the plastic parts in the battery cell is currently very thin, unable to withstand a large clamping force, and difficult to clamp, resulting in the use of laser welding between the protective film and the plastic part still remaining in the laboratory stage and difficult to apply on a large scale.
[0037] See also Figures 1 to 8 In view of the above shortcomings, this embodiment provides a battery cell, including a shell, a bare battery cell 1 and a cover. The shell has an opening, the bare battery cell 1 is arranged in the shell, the cover includes a cover body 4 and a plastic part 3, the cover body 4 is covered on the opening of the shell, and the plastic part 3 is located in the shell and between the cover body 4 and the bare battery cell 1.
[0038] The bare battery cell 1 and the plastic part 3 are covered with a protective film 2 , and the protective film 2 is provided with a through hole 6 corresponding to the plastic part 3 . A protruding portion 5 is provided on the outer surface where the plastic part 3 and the protective film 2 cooperate, and the protruding portion 5 passes through the through hole 6 .
[0039] A blocking portion 7 is provided on the portion of the protrusion 5 passing through the through hole 6. The normal direction of the connection between the outer surface of the plastic part 3 and the protrusion 5 is the protruding direction of the protrusion 5. Along the protruding direction of the protrusion 5, the projection of the blocking portion 7 is at least partially located outside the projection of the through hole 6.
[0040] The protruding direction of the protrusion 5 is the normal direction of the connection between the outer surface of the plastic part 3 and the protrusion 5, that is, the separation direction when the protective film 2 and the plastic part 3 are separated. The blocking part 7 can block the protective film 2 in the separation direction between the protective film 2 and the plastic part 3, thereby preventing the protective film 2 from being separated from the plastic part 3 and achieving the connection between the protective film 2 and the plastic part 3. The blocking part 7 can be formed by melting the part of the protrusion 5 that passes through the protective film 2 by means of laser 12 or the like and then cooling and solidifying. There is no need for direct welding between the protective film 2 and the plastic part 3, which reduces the difficulty of connecting the protective film 2 and the plastic part 3. At the same time, the thickness of the plastic part 3 is increased at the position of the protrusion 5, which avoids problems such as welding penetration of the plastic part 3, which is conducive to reducing the defective rate of the battery cell.
[0041] Specifically, Figure 7 and Figure 8As shown, in this embodiment, the portion of the protrusion 5 passing through the protective film 2 is melted by a lens pressing block 10 in cooperation with a focused laser 12. After the protrusion 5 is melted, it flows toward the protective film 2 under the action of the pressing block, and the coverage size projected in the protruding direction of the protrusion 5 becomes larger. Then, it is cooled to form a blocking portion 7, which blocks the through hole 6 of the protective film 2, thereby realizing the connection between the protective film 2 and the plastic part 3. After the protrusion 5 in the molten state contacts the protective film 2, it can also have a limited bonding effect with the protective film 2, thereby enhancing the connection strength between the plastic part 3 and the protective film 2.
[0042] In this embodiment, the lens block 10 is made of a transparent material, and the laser 12 can penetrate the lens block 10 and focus on the protrusion 5, thereby heating and melting the portion of the protrusion 5 that passes through the through hole 6 of the protective film 2. At the same time, a support leg 11 is provided below the lens block 10, and the support leg 11 can limit the pressing height of the lens block 10, thereby ensuring the height of the blocking portion 7 after melting, thereby ensuring the strength of the blocking portion 7 in the protruding direction.
[0043] Specifically, Figure 6 As shown in the figure, the Z direction is the protruding direction of the protrusion 5. In the protruding direction, the height difference between the top of the blocking part 7 and the plastic part 3 is h, and h is usually 0.3mm~0.79mm. When the overall size of the battery cell is fixed, if the height difference between the top of the blocking part 7 and the plastic part 3 in the protruding direction is too large, the size of the plastic part 3 will be reduced accordingly, the strength of the plastic part 3 will be reduced, and it will also be difficult to process. If the height difference between the top of the blocking part 7 and the plastic part 3 in the protruding direction is too small, the strength of the blocking part 7 and the connecting part is low, the blocking effect on the protective film 2 is reduced, and the protective film 2 is easily separated from the plastic part 3.
[0044] like Figure 6 As shown, in the protruding direction of the protrusion 5, the height difference between the edge of the cover body 4 close to the protrusion 5 and the top of the blocking part 7 is H, and H is usually 0.65mm~0.94mm. The edge of the cover body 4 is usually flush with the outer surface of the battery cell shell, and the bare battery cell 1 and the plastic part 3 need to be arranged in the shell. When the overall size of the battery cell is fixed, if the height difference between the edge of the cover body 4 and the top of the blocking part 7 in the protruding direction is too large, the size of the plastic part 3 needs to be reduced accordingly, the strength of the plastic part 3 is reduced, and it is also difficult to process. If the height difference between the top of the blocking part 7 and the edge of the cover body 4 is too small, it is easy to cause insufficient safety clearance between the inner wall of the shell and the blocking part 7, and the inner wall of the shell is easy to interfere with the blocking part 7 during the assembly process.
[0045] like Figure 1 to Figure 4As shown, there are multiple protrusions 5 on the plastic part 3, and the multiple protrusions 5 are arranged in sequence around the plastic part 3 to increase the connection effect between the protective film 2 and the plastic part 3. In this embodiment, the protrusions 5 are evenly arranged, the connection between the protective film 2 and the plastic part 3 is even, and the force is more balanced. In this embodiment, the protective film 2 surrounds the plastic part 3 and the bare battery cell 1 for at least one week to provide complete protection for the bare battery cell 1.
[0046] like Figure 1 to Figure 4 As shown, the protrusion 5 is cylindrical, and the through hole 6 is a circular hole matching the protrusion 5. The circular hole can reduce the stress concentration at the edge of the hole, which is beneficial to avoid the protective film 2 from tearing.
[0047] Specifically, in this embodiment, the protective film 2 is a polyethylene terephthalate film. Polyethylene terephthalate, referred to as PET, has excellent physical and mechanical properties, has the advantages of high operating temperature, fatigue resistance, friction resistance, good dimensional stability, and excellent electrical insulation, and is suitable for use inside the battery cell.
[0048] like Figure 6 As shown, in this embodiment, the blocking portion 7 is connected to the protruding portion 5 in a T-shape, and the blocking portion 7 can play a role in blocking the protective film 2 on both sides of the protruding portion 5. The protective film 2 is subjected to balanced force and the connection is reliable.
[0049] like Figure 2 to Figure 4 As shown, in this embodiment, the bare cell 1 has a tab 9, the opening of the shell is arranged corresponding to the tab 9 of the bare cell 1, the cover plate further comprises a pole 8 arranged on the cover plate body 4, and the tab 9 is electrically connected to the pole 8. The bare cell 1 can be electrically connected to the outside of the cell through the tab 9 and the pole 8.
[0050] Specifically, the bare cell 1 generally has two tabs 9, which are respectively a positive tab and a negative tab. In some embodiments, the positive tab and the negative tab are both located at the same end of the bare cell 1. Figure 4 As shown, in this embodiment, the positive pole ear and the negative pole ear are respectively located at opposite ends of the bare battery cell 1. The shell is provided with openings corresponding to the positive pole ear and the negative pole ear, respectively, and there are two cover plates, which are respectively provided corresponding to the two openings of the shell, and the positive pole ear and the negative pole ear are respectively electrically connected to the pole 8 of the corresponding cover plate. The specific arrangement of the pole ear 9 can be reasonably arranged according to the layout requirements of the battery cell.
[0051] In this embodiment, the plastic part 3 is disposed below the cover body 4 to support the cover body 4. Figure 5As shown, the plastic part 3 is provided with a through hole 13, and the pole ear 9 can pass through the through hole 13 to connect with the pole 8 provided on the cover body 4. In some embodiments, the through hole 13 is formed integrally during the injection molding of the plastic part 3. In other embodiments, the plastic part 3 is formed by combining two units, and the two plastic parts 3 are respectively provided with notches, and the notches on the two units are assembled to form the through hole 13.
[0052] In summary, in the battery cell of the utility model, since the protective film 2 is provided with a through hole 6 corresponding to the plastic part 3, a protrusion 5 is provided on the outer surface of the plastic part 3 that cooperates with the protective film 2, the protrusion 5 protrudes and passes through the through hole 6, and a blocking part 7 is provided on the part of the protrusion 5 that passes through the through hole 6, the normal direction of the connection between the outer surface of the plastic part 3 and the protrusion 5 is the protruding direction of the protrusion 5, and along the protruding direction of the protrusion 5, the projection of the blocking part 7 is at least partially located outside the projection of the through hole 6. The normal direction of the connection between the outer surface of the plastic part 3 and the protrusion 5 is also the separation direction between the protective film 2 and the plastic part 3, and the blocking part 7 can block the protective film 2 in the separation direction between the protective film 2 and the plastic part 3, thereby preventing the protective film 2 from being separated from the plastic part 3 and realizing the connection between the protective film 2 and the plastic part 3. The blocking portion 7 can be formed by melting the portion of the protrusion 5 that passes through the protective film 2 by laser 12 or other methods and then cooling and solidifying. There is no need to directly weld the protective film 2 and the plastic part 3, which reduces the difficulty of connecting the protective film 2 and the plastic part 3. At the same time, the thickness of the plastic part 3 at the protrusion 5 is increased, which is conducive to avoiding problems such as welding penetration of the plastic part 3 and improving the quality of the battery cell.
[0053] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.
Claims
1. A battery cell, characterized in that: include: a housing having an opening, A bare battery cell, wherein the bare battery cell is arranged in the housing, A cover plate, the cover plate comprises a cover plate body and a plastic part, the cover plate body is covered on the opening of the shell, the plastic part is located in the shell and between the cover plate body and the bare cell, and a protective film, the protective film covers the bare cell and the plastic part, The protective film is provided with a through hole corresponding to the plastic part, and a protruding portion protruding and passing through the through hole is provided on the outer surface of the plastic part cooperating with the protective film, and a blocking portion is provided on the portion of the protruding portion passing through the through hole, and the normal direction of the connection between the outer surface of the plastic part and the protruding portion is the protruding direction of the protruding portion, and along the protruding direction of the protruding portion, the projection of the blocking portion is at least partially located outside the projection of the through hole.
2. The battery cell according to claim 1, characterized in that: The bare cell has a tab, the opening of the shell is arranged corresponding to the tab of the bare cell, the cover plate also includes a pole arranged on the cover plate body, and the tab is electrically connected to the pole.
3. The battery cell according to claim 2, characterized in that: The bare cell has two pole ears, which are a positive pole ear and a negative pole ear, respectively. The positive pole ear and the negative pole ear are located at opposite ends of the bare cell. The shell is provided with the openings corresponding to the positive electrode ear and the negative electrode ear respectively, there are two cover plates, and the two cover plates are respectively provided corresponding to the two openings of the shell, and the positive electrode ear and the negative electrode ear are respectively electrically connected to the poles corresponding to the cover plates.
4. The battery cell according to claim 1, characterized in that: Along the protruding direction of the protruding portion, the height difference between the top of the blocking portion and the plastic part is 0.3 mm to 0.79 mm.
5. The battery cell according to claim 1, characterized in that: Along the protruding direction of the protruding portion, the height difference between the edge of the cover plate body close to the protruding portion and the top of the blocking portion is 0.65 mm to 0.94 mm.
6. The battery cell according to claim 1, characterized in that: There are multiple protrusions, and the multiple protrusions are arranged in sequence around the plastic part.
7. The battery cell according to claim 1, characterized in that: The protective film surrounds the plastic part and the bare battery cell.
8. The battery cell according to claim 1, characterized in that: The protrusion is cylindrical, and the through hole is a circular hole matching the protrusion.
9. The battery cell according to claim 1, characterized in that: The protective film is a polyethylene terephthalate film.
10. The battery cell according to claim 1, characterized in that: The blocking portion and the protruding portion are connected in a T shape.