Cover plate assembly, battery cell and assembling method of battery cell

Abstract

The invention relates to the technical field of battery cells, and discloses a cover plate assembly, a battery cell and an assembling method of the battery cell, and the cover plate assembly comprises a cover plate body, a pressure relief structure and a top cover patch. According to the cover plate assembly with the structure, the protective film of the pressure relief structure and the top cover patch are integrally arranged, the cover plate assembly is mounted on the shell of the battery, the weak area of the cover plate assembly is opposite to the pressure relief structure, and the strength of the weak area is lower than that of other solid parts of the top cover patch, so that normal opening and pressure relief of the pressure relief structure can be ensured. The protective film and the top cover patch are integrally arranged, so that the number of the cover plate assembly and the number of battery cell parts are reduced while the functions of the protective film and the top cover patch are respectively realized, and the manufacturing cost of the cover plate assembly and the manufacturing cost of the battery cell can be reduced; and during mounting, the protective film and the top cover patch can be mounted at the same time only through one-step operation, so that the mounting process of the battery cell is effectively simplified, and the production efficiency of the battery cell is favorably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery cells, and in particular to a cover plate assembly, a battery cell and a method for assembling the battery cell. Background Art

[0002] like Figure 1 As shown, the battery cell includes a cover plate assembly, a shell and a pole group, and the cover plate assembly includes a cover plate body 1', poles and insulating parts and other structures. A mounting hole is provided on the cover plate body 1', and the pressure relief structure 2' is installed in the mounting hole. A protective film 4' is provided on the cover plate body outside the mounting hole. The protective film is used to prevent external impurities from falling into the pressure relief structure, and can also prevent external sharp objects from piercing the pressure relief structure. When assembling the battery cell, the protective film is first installed on the cover plate body. After the cover plate assembly is installed on the shell, a top cover patch 3' is affixed to the surface of the cover plate body to protect the cover plate assembly and realize the insulation of the cover plate assembly from the outside. The cover plate assembly has many parts, high production cost, and complicated installation process. Summary of the invention

[0003] In view of this, the present invention provides a cover plate assembly, a battery cell and a method for assembling the battery cell to solve the problem in the prior art that the cover plate assembly has many parts, high manufacturing cost and complex battery cell installation process.

[0004] In a first aspect, the present invention provides a cover plate assembly, comprising:

[0005] The cover plate body is provided with a first mounting hole;

[0006] A pressure relief structure, disposed in the first mounting hole;

[0007] A top cover patch is arranged on the outer wall surface of the cover plate body. A weak area is arranged on the top cover patch. The strength of the weak area is lower than the strength of other solid parts of the top cover patch. The weak area is arranged above the first mounting hole. The pressure relief structure can break through the weak area when it is opened.

[0008] Beneficial effects: The cover plate assembly of this structure sets the protective film of the pressure relief structure and the top cover patch as one piece. The cover plate assembly is installed on the battery shell, and its weak area is arranged opposite to the pressure relief structure. The strength of the weak area is lower than the strength of other solid parts of the top cover patch. The strength of the weak area is sufficient to ensure that the pressure can break through the weak area when the pressure relief structure is opened, thereby ensuring the normal opening and pressure relief of the pressure relief structure. When the weak area is not broken, it can protect the pressure relief structure inside it, prevent foreign particles and impurities from entering the pressure relief structure, which is conducive to ensuring the normal working effect of the pressure relief structure, and prevent foreign sharp objects from damaging the pressure relief structure; the top cover patch plays an insulating protection role. The protective film and the top cover patch are set as one piece, which reduces the number of cover plate assemblies and battery cell parts while realizing the functions of the protective film and the top cover patch respectively, and can reduce the production cost of the cover plate assembly and the battery cell; during installation, only one step is required to install the protective film and the top cover patch at the same time, which effectively simplifies the installation process of the battery cell and is conducive to improving the production efficiency of the battery cell.

[0009] In an optional embodiment, a score line is provided at the outer edge of the weak zone, and the thickness of the score line is less than the thickness of the top cover patch.

[0010] Beneficial effect: When the pressure relief structure is opened, the high pressure breaks through the score line, so that the weak area is broken from the score line as a whole, so as to form an exhaust channel on the top cover patch, and the high-pressure gas is discharged from the exhaust channel to achieve pressure relief. The weak area structure is simple and reliable, which can effectively ensure the opening and pressure relief of the pressure relief structure.

[0011] In an optional embodiment, the score line is arranged around the weakened area.

[0012] Beneficial effect: When the pressure relief structure is opened, the weak area is completely separated from the top cover patch along the score line area to form an exhaust hole on the top cover patch. The exhaust hole is unobstructed outside, which can ensure the exhaust rate and improve the pressure relief rate of the battery cell.

[0013] In an optional embodiment, the thickness of the weak area is less than or equal to the thickness of the top cover patch.

[0014] Beneficial effect: The weak area is located inside the score line, and the thickness of the weak area is less than or equal to the thickness of the top cover patch, so that the weak area is easily broken to form an exhaust channel when subjected to high-pressure impact.

[0015] In an optional embodiment, the top cover patch is provided with adhesive backing, the top cover patch is adhered to the cover plate body, an air intake channel is provided on the weak area, and the air intake channel is connected to the pressure relief structure.

[0016] Beneficial effect: During the air tightness test, helium is sprayed into the pressure relief mechanism through the air inlet channel, and the helium permeation is detected on one side of the inner wall surface of the cover body to realize the air tightness test of the pressure relief structure.

[0017] In an optional embodiment, the thickness of the top cover patch is t, 0.15mm≤t≤0.5mm.

[0018] Beneficial effect: t≥0.15mm, such a setting can prevent the top cover patch from being pierced by external sharp objects due to its thin thickness, which is conducive to ensuring the insulation protection effect of the top cover patch. At the same time, t≤0.5mm, such a setting can prevent the top cover patch from being too thick and causing an increase in its material cost.

[0019] In an optional embodiment, the circumferential outer edge of the top cover patch is spaced apart from the circumferential outer edge of the cover plate body.

[0020] Beneficial effect: This arrangement can prevent the top cover patch from interfering with the welding of the cover plate body and the shell.

[0021] In an optional embodiment, the distance between the circumferential outer edge of the top cover patch and the circumferential outer edge of the cover plate body is d, and 1.5 mm≤d≤5 mm.

[0022] Beneficial effect: This arrangement can ensure that there is sufficient spacing between the circumferential outer edge of the top cover patch and the circumferential outer edge of the cover body to avoid interference during welding of the cover body and the shell, and at the same time prevent the spacing between the two from being too large to affect the insulation protection effect of the top cover patch.

[0023] In a second aspect, the present invention further provides a battery cell, comprising any one of the above-mentioned cover plate assembly, a shell and a pole group, the shell is provided with an opening, the pole group is arranged in the shell, and the cover plate assembly is arranged on the opening. The battery cell includes the cover plate assembly, which has the same technical effect as the cover plate assembly, and will not be repeated here.

[0024] In a second aspect, the present invention further provides a method for assembling a battery cell, which is used to assemble the above-mentioned battery cell, comprising:

[0025] The pole group is arranged in the housing;

[0026] Installing the pressure relief structure in the first mounting hole;

[0027] Fixing the top cover patch on the outer wall surface of the cover body to form a cover assembly;

[0028] The cover plate body is welded to the shell.

[0029] Beneficial effects: By adopting the battery cell assembly method, the top cover patch can be directly fixed on the outer wall surface of the cover body when assembling the battery cell to complete the installation of the explosion-proof valve protective film and the top cover patch, which can simplify the assembly steps and improve the production efficiency of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 An exploded diagram of the battery cell described in the background technology of the present invention;

[0032] Figure 2 A top view of the battery cell described in the background technology of the present invention;

[0033] Figure 3 is a schematic diagram of a top cover patch in a cover plate assembly according to an embodiment of the present invention;

[0034] Figure 4 is a schematic diagram of a top cover patch in a cover plate assembly according to another embodiment of the present invention;

[0035] Figure 5 A schematic diagram of a top cover patch in a cover plate assembly according to another embodiment of the present invention;

[0036] Figure 6 is a schematic diagram of a top cover patch in a cover plate assembly according to an embodiment of the present invention;

[0037] Figure 7 is a schematic diagram of a top cover patch in a cover plate assembly according to another embodiment of the present invention;

[0038] Figure 8 An exploded diagram of a battery cell according to an embodiment of the present invention;

[0039] Fig. 9 A top view of a battery cell according to an embodiment of the present invention;

[0040] Fig.10 This is a top view of the battery cell after the top cover patch is removed according to an embodiment of the present invention.

[0041] Description of reference numerals:

[0042] 1', cover body; 2', pressure relief structure; 3', top cover patch; 4', protective film;

[0043] 1. Cover body; 2. Pressure relief structure; 3. Top cover patch; 31. Weak area; 311. Air intake channel; 32. Score line; 33. Adhesive backing; 4. Shell. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0045] like Figure 1 and Figure 2 As shown, the battery cell in the related art includes a cover plate assembly, a shell and a pole group. The cover plate assembly includes a cover plate body 1'. The cover plate body 1' is provided with a mounting hole. The pressure relief structure 2' is installed in the mounting hole. A protective film 4' is provided on the cover plate body outside the mounting hole. When installing the battery cell, the pressure relief structure is first installed in the mounting hole, and then the protective film is fixed on the cover plate body above the pressure relief structure to form a cover plate assembly. The cover plate assembly is then welded to the shell through the cover plate body, and finally the top cover patch 3' is fixed on the outer wall surface of the cover plate body. An avoidance hole is provided on the top cover patch, and the avoidance hole is arranged opposite to the protective film and the pressure relief structure to prevent the top cover patch from interfering with the opening and pressure relief of the pressure relief structure. This structure has many battery cell parts, and the protective film and the top cover patch need to be manufactured and installed separately, resulting in high battery cell manufacturing costs and complex installation processes.

[0046] Combine the following Figures 3 to 10 , describing an embodiment of the present invention.

[0047] According to an embodiment of the present invention, on the one hand, a cover plate assembly is provided, including a cover plate body 1, a pressure relief structure 2 and a top cover patch 3.

[0048] Among them, a first mounting hole is provided on the cover body 1; the pressure relief structure 2 is provided in the first mounting hole; the top cover patch 3 is provided on the outer wall surface of the cover body 1, and a weak area 31 is provided on the top cover patch 3. The strength of the weak area 31 is lower than the strength of other solid parts of the top cover patch 3. The weak area 31 is provided above the first mounting hole, and the pressure relief structure 2 can break through the weak area 31 when it is opened.

[0049] The cover plate assembly of this structure sets the protective film of the pressure relief structure 2 and the top cover patch 3 as one body. The cover plate assembly is installed on the battery housing 4. Its weak area 31 is arranged opposite to the pressure relief structure 2. The strength of the weak area 31 is lower than the strength of other solid parts of the top cover patch 3. The strength of the weak area 31 is sufficient to ensure that the pressure can break through the weak area 31 when the pressure relief structure 2 is opened, thereby ensuring the normal opening and pressure relief of the pressure relief structure 2. When the weak area 31 is not broken, it can protect the pressure relief structure 2 inside it, prevent foreign particles and impurities from entering the pressure relief structure 2, which is conducive to ensuring the normal working effect of the pressure relief structure 2, and prevent foreign sharp objects from damaging the pressure relief structure 2; the top cover patch 3 plays an insulating protection role. The protective film and the top cover patch 3 are set as one body, which reduces the number of cover plate assemblies and battery cell parts while realizing the functions of the protective film and the top cover patch 3 respectively, and can reduce the production cost of the cover plate assembly and the battery cell; during installation, the protective film and the top cover patch 3 can be installed at the same time in one step, which effectively simplifies the installation process of the battery cell and is conducive to improving the production efficiency of the battery cell.

[0050] Optionally, in some embodiments, a notch line 32 is provided at the outer edge of the weak area 31, and the thickness of the notch line 32 is less than the thickness of the top cover patch 3. When the internal pressure of the battery cell increases abnormally, when the pressure relief structure 2 is opened, the high pressure breaks through the notch line 32, so that the weak area 31 as a whole is broken from the notch line 32 to form an exhaust channel on the top cover patch 3, and the high-pressure gas is discharged from the exhaust channel to achieve pressure relief. The weak area 31 has a simple and reliable structure, which can effectively ensure the pressure relief of the pressure relief structure 2.

[0051] In some embodiments, Figures 3 to 7 As shown, the score line 32 is arranged around the weak area 31. When the pressure relief structure 2 is opened, the weak area 31 is completely separated from the top cover patch 3 along the score line 32 to form an exhaust hole on the top cover patch 3. The exhaust hole is unobstructed outside, which can ensure the exhaust rate and improve the pressure relief rate of the battery cell.

[0052] In other embodiments, the score line 32 may also be partially disposed around the weak area 31 , so that when the pressure relief structure 2 is opened, the score line 32 may break through a portion of the weak area 31 to form an exhaust passage.

[0053] The area and shape of the weak area 31 correspond to the pressure relief structure 2. Optionally, in some embodiments, the cross section of the pressure relief structure 2 is elliptical, and the score line 32 and the weak area 31 are elliptical.

[0054] In some embodiments, the thickness of the weak area 31 is less than or equal to the thickness of the top cover patch 3. The weak area 31 is located inside the score line 32, and the thickness of the weak area 31 is less than or equal to the thickness of the top cover patch 3, so that the weak area 31 is ruptured to form an exhaust channel when subjected to high pressure impact.

[0055] In some embodiments, the thickness of the weakened area 31 is the same as the thickness of other parts of the top cover patch 3 .

[0056] In other embodiments, the thickness of the weak area 31 is smaller than the thickness of other portions of the top cover patch 3 .

[0057] like Figure 6 and Figure 7 As shown, in some optional embodiments, a backing adhesive 33 is provided on the top cover patch 3, the top cover patch 3 is bonded to the cover body 1, an air inlet channel 311 is provided on the weak area 31, and the air inlet channel 311 is connected to the pressure relief structure 2. After the pressure relief structure 2 is installed, its air tightness needs to be tested, the backing adhesive 33 is provided on the inner wall surface of the top cover patch 3 facing the cover body 1, and the air inlet channel 311 runs through the weak area 31 and the backing adhesive 33. When the air tightness is tested, helium is sprayed into the pressure relief mechanism through the air inlet channel 311, and the helium permeation is tested on one side of the inner wall surface of the cover body 1 to achieve the air tightness test of the pressure relief structure 2.

[0058] Optionally, in some embodiments, Figure 3 As shown, the air inlet channel 311 includes a through hole arranged on the weak area 31. During the air tightness test, helium is sprayed into the pressure relief structure 2 through the through hole. The through hole can be a circular hole, a rectangular hole, a triangular hole, etc.

[0059] In other embodiments, Figure 4 As shown, the air inlet channel 311 includes a gap structure arranged on the weak area 31 , and the gap structure is formed by scratches that penetrate the weak area 31 and the backing glue 33 .

[0060] In other embodiments, Figure 5 As shown, the air inlet channel 311 includes a notch arranged on the weak area 31 , and the notch extends from the weak area 31 to the edge of the top cover patch 3 .

[0061] like Figure 6 As shown, in some embodiments, the adhesive backing 33 covers the top cover patch 3 and is arranged toward the inner wall surface of the cover body 1. At this time, the air inlet channel 311 is located in the weak area 31, and the air inlet channel 311 is arranged opposite to the pressure relief structure 2 so that helium can be introduced into the pressure relief structure 2 during the air tightness test.

[0062] like Figure 7 As shown, in other embodiments, the adhesive 33 can be arranged around the outer edge of the inner wall surface of the top cover patch 3.

[0063] In some optional embodiments, the thickness of the top cover patch 3 is t, 0.15mm≤t≤0.5mm. t≥0.15mm, such a setting can prevent the top cover patch 3 from being pierced by external sharp objects due to its too small thickness, which is conducive to ensuring the insulation protection effect of the top cover patch 3. At the same time, t≤0.5mm, such a setting can prevent the top cover patch 3 from being too thick and causing an increase in its material cost.

[0064] Optionally, the total thickness of the top cover patch 3 including the adhesive 33 is 0.3 mm.

[0065] In the cover plate assembly of the present structure, the protective film of the pressure relief structure 2 is integrally arranged with the top cover patch 3. The top cover patch 3 is first bonded to the cover plate body 1 to form a cover plate assembly, and then the cover plate assembly is welded to the shell 4 of the battery cell through the cover plate body 1. If the circumferential outer edge of the top cover patch 3 exceeds the circumferential outer edge of the cover plate body 1, or the circumferential outer edge of the top cover patch 3 is flush with the circumferential outer edge of the cover plate body 1, the top cover patch 3 will interfere with the welding of the cover plate body 1 and the shell 4. In order to avoid this problem, in some embodiments, the circumferential outer edge of the top cover patch 3 is spaced from the circumferential outer edge of the cover plate body 1, that is, the outer edge of the top cover patch 3 is located on the inner side of the outer edge of the cover plate body 1. This arrangement can prevent the top cover patch 3 from interfering with the welding of the cover plate body 1 and the shell 4.

[0066] In some optional embodiments, the spacing between the circumferential outer edge of the top cover patch 3 and the circumferential outer edge of the cover body 1 is d, 1.5mm≤d≤5mm. This setting can ensure that there is sufficient spacing between the circumferential outer edge of the top cover patch 3 and the circumferential outer edge of the cover body 1 to avoid interference during the welding process of the cover body 1 and the shell 4, and at the same time prevent the spacing between the two from being too large to affect the insulation protection effect of the top cover patch 3.

[0067] In some optional embodiments, the cover body 1 is in the shape of a rectangular plate, and the top cover patch 3 is in the shape of a rectangle. The cover assembly also includes a pole, and a liquid injection hole is provided on the cover body 1. The top cover patch 3 is also provided with a pole avoidance hole and a liquid injection avoidance hole, the pole avoidance hole is sleeved outside the pole, and the liquid injection avoidance hole is provided above the liquid injection hole, so as to inject electrolyte into the battery cell through the liquid injection avoidance hole.

[0068] In some embodiments, the weak area 31 of the top cover patch 3 is made of the same material as the other parts of the top cover patch 3. When the protective film of the pressure relief structure 2 and the top cover patch 3 are separately provided, the materials of the two are different, and different materials need to be used to make the protective film and the top cover patch 3 respectively, resulting in an increase in the material cost of the battery cell. After the protective film and the top cover patch 3 are integrally provided, the two are made of the same material to reduce the material cost.

[0069] Optionally, the material of the top cover patch 3 includes insulating materials such as PP, PET, PE, etc., and such a setting can achieve a good insulation protection effect.

[0070] Preferably, in some embodiments, the top cover patch 3 is made of a transparent material so that the shape of the pressure relief structure 2 can be observed inward through the top cover patch 3 .

[0071] In some optional embodiments, the pressure relief structure 2 includes an explosion-proof valve, and the cover plate body 1 includes a plain aluminum plate.

[0072] According to an embodiment of the present invention, on the other hand, a battery cell is provided, including the above-mentioned cover plate assembly, shell 4 and pole group, the shell 4 is provided with an opening, the pole group is arranged in the shell 4, and the cover plate assembly is arranged on the opening.

[0073] In the battery cell of this structure, the protective film of the pressure relief structure 2 is integrated with the top cover patch 3. The strength of the weak area 31 is sufficient to allow the pressure to break through the weak area 31 when the pressure relief structure 2 is opened, thereby ensuring the normal opening and pressure relief of the pressure relief structure 2. When the weak area 31 is not broken, it can protect the pressure relief structure 2 inside it, preventing foreign particles and impurities from entering the pressure relief structure 2, which is beneficial to ensuring the normal working effect of the pressure relief structure 2, and preventing foreign sharp objects from damaging the pressure relief structure 2; the top cover patch 3 plays an insulating and protective role. The protective film and the top cover patch 3 are integrated, which reduces the number of cover plate components and battery cell parts while realizing the functions of the protective film and the top cover patch 3 respectively, and can reduce the production cost of the cover plate components and the battery cell; during installation, the protective film and the top cover patch 3 can be installed at the same time in one step, which effectively simplifies the installation process of the battery cell and is beneficial to improving the production efficiency of the battery cell.

[0074] According to an embodiment of the present invention, on the other hand, a method for assembling a battery cell is provided, which is used to assemble the above-mentioned battery cell, comprising:

[0075] The pole group is arranged in the housing 4;

[0076] Install the pressure relief structure 2 in the first installation hole;

[0077] The top cover patch 3 is fixed on the outer wall surface of the cover body 1 to form a cover assembly;

[0078] The cover body 1 is welded to the shell 4 .

[0079] The protective film and the top cover patch 3 of the explosion-proof valve in the related art are both separately arranged. At the same time, in order to avoid the top cover patch 3 interfering with the welding of the cover body 1 and the battery cell shell 4, the related art first fixes the protective film on the cover body 1 to protect the explosion-proof valve, welds the cover body 1 to the shell 4, and then glues and fixes the top cover patch 3 on the cover body 1. The battery cell installation steps are numerous and the battery cell assembly process is complicated.

[0080] The explosion-proof valve protective film and the top cover patch 3 are integrally arranged. By adopting the assembly method of the battery cell, the top cover patch 3 can be directly fixed on the outer wall surface of the cover body 1 when assembling the battery cell to complete the installation of the explosion-proof valve protective film and the top cover patch 3, which can simplify the assembly steps and improve the production efficiency of the battery cell.

[0081] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A cover plate assembly, characterized in that: include: The cover body is provided with a first mounting hole; A pressure relief structure, disposed in the first mounting hole; A top cover patch is arranged on the outer wall surface of the cover plate body. A weak area is arranged on the top cover patch. The strength of the weak area is lower than the strength of other solid parts of the top cover patch. The weak area is arranged above the first mounting hole. The pressure relief structure can break through the weak area when it is opened.

2. The cover plate assembly according to claim 1, characterized in that: The outer edge of the weak zone is provided with a scoring line, and the thickness of the scoring line is less than the thickness of the top cover patch.

3. The cover plate assembly according to claim 2, characterized in that: The score line is disposed around the weakened area.

4. The cover plate assembly according to any one of claims 1 to 3, characterized in that: The thickness of the weak area is less than or equal to the thickness of the top cover patch.

5. The cover plate assembly according to any one of claims 1 to 3, characterized in that: The top cover patch is provided with adhesive backing, the top cover patch is bonded to the cover plate body, an air intake channel is provided on the weak area, and the air intake channel is connected to the pressure relief structure.

6. The cover plate assembly according to any one of claims 1 to 3, characterized in that: The thickness of the top cover patch is t, 0.15mm≤t≤0.5mm.

7. The cover plate assembly according to any one of claims 1 to 3, characterized in that: The circumferential outer edge of the top cover patch is spaced apart from the circumferential outer edge of the cover plate body.

8. The cover plate assembly according to claim 7, characterized in that: The distance between the circumferential outer edge of the top cover patch and the circumferential outer edge of the cover plate body is d, 1.5mm≤d≤5mm.

9. A battery cell, characterized in that: It comprises the cover plate assembly, shell and pole group according to any one of claims 1 to 8, wherein the shell is provided with an opening, the pole group is arranged in the shell, and the cover plate assembly is arranged on the opening.

10. A method for assembling a battery cell, characterized in that: For assembling the battery cell according to claim 9, comprising: The pole group is arranged in the housing; Installing the pressure relief structure in the first mounting hole; The top cover patch is fixed on the outer wall surface of the cover body to form a cover assembly; and the cover body is welded to the shell.

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