Top sealing tool, battery cell and battery pack

Abstract

The invention relates to the technical field of battery cells, and discloses a top sealing tool, a battery cell and a battery pack, and the top sealing tool comprises a supporting plate and a pressing plate. The height f of the limiting step and 2t of the two layers of packaging films meet the condition that f / 2t is greater than or equal to 0.83, so that the height of the limiting step can be prevented from being too small, the total thickness of the two layers of packaging films after heat sealing can be ensured, overmelting of the packaging films caused by overpressure can be avoided, the bonding force between the PP layer and the non-PP layer of the packaging films can be ensured, stripping of the PP layer and the non-PP layer in the use process of the battery cell can be avoided, and the service life of the battery cell can be prolonged. The sealing performance of the tab of the battery cell can be ensured; meanwhile, the height f of the limiting step and 2t of the two layers of packaging films meet the condition that f / 2t is smaller than or equal to 0.9, so that the height of the limiting step can be prevented from being too large, the thickness of the two layers of packaging films after heat sealing can be prevented from being too large, sufficient hot pressing of the packaging films is guaranteed, insufficient hot pressing strength is avoided, and the packaging strength between the two layers of packaging films after heat sealing can be guaranteed; and the sealing performance of the tab of the battery cell can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of battery cells, and particularly to a top-sealing tooling, a battery cell and a battery pack. Background Art

[0002] A soft-pack battery cell includes a pole group and a packaging film, etc. The packaging film protects the pole group. During the assembly process of the packaging film and the pole group, a receiving groove is first stamped and formed at a specified position of the packaging film, the pole group is placed in the receiving groove, and then the packaging film is folded and heat-sealed to complete the packaging of the pole group.

[0003] During the top-sealing process of the battery cell, a top-sealing tooling is used. The top-sealing tooling includes a support plate and a pressing plate. First, the sealing edge of the battery cell is placed on the support plate, and the pressing plate moves downward to press against the sealing edge of the battery cell. The pressing plate generates heat to complete the pressing of the sealing edge. During the heat-sealing process, the downward stroke of the pressing plate is controlled to control the hot-pressing process. If the downward distance of the pressing plate is too large, it is easy to cause overpressure, resulting in over-melting of the packaging film and affecting the sealing performance of the battery cell; if the downward distance of the pressing plate is insufficient, the packaging film cannot be fully hot-pressed, the heat melting of the packaging film is insufficient, the packaging strength is insufficient, and the packaging film is easy to crack during subsequent use, which will also affect the sealing performance of the battery cell. Summary of the Invention

[0004] In view of this, the present invention provides a top-sealing tooling, a battery cell and a battery pack to solve the problem that the top-sealing tooling in the prior art is prone to overpressure and over-melting or insufficient hot-pressing strength during heat-sealing, thus affecting the sealing performance of the battery cell.

[0005] In a first aspect, the present invention provides a top-sealing tooling, including:

[0006] A support plate;

[0007] A pressing plate, adapted to be pressed above the support plate; at least one side in the length direction of one of the top surface of the support plate and the bottom surface of the pressing plate is provided with a limiting step, and a positioning post is provided on the limiting step; the height of the limiting step is f, and the thickness of the single-layer packaging film of the battery cell is t, and the units of f and t are mm, and 0.83 ≤ f / 2t ≤ 0.9; the support plate or the pressing plate is provided with a positioning hole cooperating with the positioning post, and the positioning post is inserted into the positioning hole.

[0008] Beneficial effects: When the top-sealing tooling of this structure is in use, first place the encapsulation edge of the battery cell on the support plate, move the pressure plate downward to press on the upper side of the encapsulation edge, and insert the positioning post into the positioning hole to guide the downward movement of the pressure plate. When the bottom surface of the pressure plate or the top surface of the support plate touches the limit step, the pressure plate stops pressing down. The pressure plate is limited by the limit step, and the downward pressing stroke of the pressure plate can be accurately controlled; the bottom surface of the battery cell encapsulation film is located on the top surface of the support plate, and the height of the limit step is the total thickness of the two layers of encapsulation film on both sides of the tab after hot pressing. The height f of the limit step and the two layers of encapsulation film 2t satisfy f / 2t≥0.83. In this way, it can prevent the height of the limit step from being too small, ensure the total thickness of the two layers of encapsulation film after heat sealing, avoid over-pressing resulting in over-melting of the encapsulation film, ensure the bonding force between the PP layer and the non-PP layer of the encapsulation film, avoid peeling between the PP layer and the non-PP layer during the use of the battery cell, and ensure the sealing performance at the tab of the battery cell; at the same time, the height f of the limit step and the two layers of encapsulation film 2t satisfy f / 2t≤0.9. Such a setting can prevent the height of the limit step from being too large, prevent the thickness of the two layers of encapsulation film from being too large after heat sealing, ensure sufficient hot pressing of the encapsulation film, avoid insufficient hot pressing strength, ensure the encapsulation strength between the two layers of encapsulation film after heat sealing, and ensure the sealing performance at the tab of the battery cell.

[0009] In an optional embodiment, the positioning post is cylindrical, and the diameter of the positioning post is d1, where 4mm≤d1≤50mm.

[0010] Beneficial effects: In this way, the diameter of the positioning post can be controlled within a suitable size to ensure its structural strength, and at the same time, it can avoid waste of materials and space caused by too large a diameter of the positioning post.

[0011] In an optional embodiment, the depth h of the positioning post inserted into the positioning hole is 3mm≤h≤50mm.

[0012] Beneficial effects: In this way, the depth h of the positioning post inserted into the positioning hole can be controlled within a suitable range to ensure the depth of the positioning post inserted into the positioning hole, avoid slipping at the positioning part of the pressure plate and the support plate when pressing up and down, ensure the positioning effect of the positioning post, and thus can effectively hot press the encapsulation film; at the same time, it can also reduce waste of materials and space and improve the space utilization rate of the top-sealing tooling.

[0013] In an optional embodiment, a first chamfered inclined surface is provided on the outer peripheral wall of the end of the positioning post away from the limit step. The horizontal width w between the end of the first chamfered inclined surface facing the center of the positioning post and the outer peripheral wall of the root of the positioning post satisfies 0.2mm≤w≤d1 / 3.

[0014] Beneficial effects: Such a setting can prevent the inclination angle of the first chamfered slope from being too small, ensuring its guiding effect. At the same time, it can prevent the inclination angle of the first chamfered slope from being too large due to w being too large, and prevent the top of the positioning post from being too sharp, avoiding damage to the pressing plate and operators, and ensuring the safety during the operation of the jacking tooling.

[0015] In an alternative embodiment, the included angle between the first chamfered slope and the end face of the positioning post is g, and 100° ≤ g ≤ 150°.

[0016] Beneficial effects: This can control the g angle and the inclination angle of the first chamfered slope within a suitable range, ensuring the guiding effect of the first chamfered slope and ensuring the rapid docking of the positioning post and the positioning hole.

[0017] In an alternative embodiment, a second chamfered slope is provided at the orifice of the positioning hole. Along the height direction of the top-sealing tooling, the distance between the end of the second chamfered slope facing the inside of the positioning hole and the end face of the positioning hole is C, and 0.2 mm ≤ C ≤ 5 mm.

[0018] Beneficial effects: Such a setting can control the inclination angle of the second chamfered slope within a suitable range, facilitating the sliding of the positioning post into the positioning hole.

[0019] In an alternative embodiment, a support post is provided on the support plate or the pressing plate, the limiting step is provided on the support post, and the horizontal distance between the outer peripheral wall of the positioning post and the outer peripheral wall of the support post is L, and L ≥ 2 mm.

[0020] Beneficial effects: Such a setting can ensure that there is a sufficient area of support posts around the outer periphery of the positioning post, ensuring the support area of the support posts, thereby being able to ensure the support of the support posts for the positioning post, avoiding dimensional deformation of the positioning post or the limiting step after multiple press-fittings, ensuring the height of the limiting step, and thus being able to control the thickness of the encapsulation film within a suitable range after heat-sealing.

[0021] In an alternative embodiment, both the support post and the limiting step are cylindrical, the limiting step and the support post are coaxially arranged and have the same diameter, the positioning post is arranged in the middle of the limiting step, the diameter of the support post is d2, and (d2 - d1) / 2 ≥ 2 mm.

[0022] In a second aspect, the present invention also provides an electric core, which is top-sealed and encapsulated by using the top-sealing tooling according to any one of the above.

[0023] Beneficial effects: When the bottom surface of the pressing plate or the top surface of the supporting plate touches the limiting step during the top sealing of the battery cell with this structure, the pressing plate stops pressing down. The limiting step limits the pressing plate, and the pressing stroke of the pressing plate can be accurately controlled. The height f of the limiting step and the two-layer packaging film 2t satisfy f / 2t≥0.83, which can prevent the height of the limiting step from being too small, ensure the total thickness of the two-layer packaging film after heat sealing, avoid overpressure causing the packaging film to over-melt, ensure the bonding force between the PP layer and the non-PP layer of the packaging film, avoid peeling between the PP layer and the non-PP layer during the use of the battery cell, and ensure the sealing performance at the tab of the battery cell. At the same time, the height f of the limiting step and the two-layer packaging film 2t satisfy f / 2t≤0.9. Such a setting can prevent the height of the limiting step from being too large, prevent the thickness of the two-layer packaging film after heat sealing from being too large, ensure sufficient hot pressing of the packaging film, avoid insufficient hot pressing strength, ensure the packaging strength between the two-layer packaging films after heat sealing, ensure the sealing performance at the tab of the battery cell, and ensure the safety performance of the battery cell.

[0024] In a third aspect, the present invention also provides a battery pack, including the above-mentioned battery cell. The battery pack includes the battery cell and has the same technical effects as the battery cell, which will not be elaborated here. Description of the Drawings

[0025] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is the front view of a top-sealing tooling according to an embodiment of the present invention;

[0027] Figure 2 It is Figure 1 the top view of the top-sealing tooling shown in cooperation with the battery cell during hot pressing and encapsulation;

[0028] Figure 3 It is Figure 2 the sectional view taken along the A-A direction of ;

[0029] Figure 4 It is Figure 3 the partial enlarged schematic view of A in ;

[0030] Figure 5 It is Figure 3 the partial enlarged schematic view of A in ;

[0031] Figure 6 It is Figure 3 the partial enlarged schematic view of B in ;

[0032] Figure 7 For Figure 1 The three-dimensional structure diagram of the top-sealing tooling when hot-pressing and encapsulating in cooperation with the battery cell is shown in the figure;

[0033] Figure 8 For Figure 1 The explosion diagram of the top-sealing tooling and the battery cell shown in the figure;

[0034] Figure 9 It is the three-dimensional structure diagram of the battery cell tab.

[0035] Explanation of reference numerals:

[0036] 1. Top-sealing tooling; 11. Support plate; 111. Limit step; 112. Positioning post; 1121. First chamfered inclined surface; 113. Support post; 12. Pressing plate; 121. Positioning hole; 1211. Second chamfered inclined surface; 2. Battery cell; 21. Encapsulation film; 22. Tab; 23. Insulating part. Specific implementation manners

[0037] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] In the related art, the top-sealing tooling 1 is used to perform top-sealing on the battery cell 2. The top-sealing tooling 1 includes a support plate 11 and a pressing plate 12. During the top-sealing process, first, the encapsulation edge of the battery cell 2 is placed on the support plate 11, and the pressing plate 12 moves downward to press against the encapsulation edge of the battery cell 2. The pressing plate 12 generates heat to complete the pressing of the encapsulation edge. During the heat-sealing process, the heat-pressing process is controlled by controlling the downward stroke of the pressing plate 12. If the downward distance of the pressing plate 12 is too large, it is easy to cause overpressure, resulting in over-melting of the encapsulation film 21, affecting the bonding force between the PP layer and the non-PP layer of the encapsulation film, causing the seal failure at the tab 22, and affecting the sealing performance of the battery cell 2; if the downward distance of the pressing plate 12 is insufficient, the encapsulation film 21 cannot be fully hot-pressed, the encapsulation film 21 is not fully melted, the encapsulation strength is insufficient, and the encapsulation film 21 is prone to cracking during subsequent use, which will also affect the sealing performance of the battery cell 2.

[0039] The following will be combined with Figures 1 to 9 to describe the embodiments of the present invention.

[0040] According to an embodiment of the present invention, on the one hand, a top-sealing tooling 1 is provided, which includes a support plate 11 and a pressing plate 12. Among them, the pressing plate 12 is adapted to be press-connected above the support plate 11; at least one side in the length direction of one of the top surface of the support plate 11 and the bottom surface of the pressing plate 12 is provided with a limiting step 111, and a positioning post 112 is provided on the limiting step 111; the height of the limiting step 111 is f, and the thickness of the single-layer encapsulation film 21 of the battery cell 2 is t, and the units of f and t are mm, and 0.83 ≤ f / 2t ≤ 0.9; the support plate 11 or the pressing plate 12 is provided with a positioning hole 121 that cooperates with the positioning post 112, and the positioning post 112 is inserted into the positioning hole 121.

[0041] When the top-sealing tooling 1 with this structure is in use, first place the encapsulation edge of the battery cell 2 on the support plate 11, move the pressing plate 12 downward to be press-connected above the encapsulation edge, and the positioning post 112 is inserted into the positioning hole 121 to guide the downward movement of the pressing plate 12. When the bottom surface of the pressing plate 12 or the top surface of the support plate 11 touches the limiting step 111, the pressing plate 12 stops pressing down. The pressing plate 12 is limited by the limiting step 111, and the downward pressing stroke of the pressing plate 12 can be accurately controlled; the bottom surface of the encapsulation film 21 of the battery cell 2 is located on the top surface of the support plate 11, and the height of the limiting step 111 is the total thickness of the two layers of encapsulation film 21 on both sides of the tab 22 after hot pressing. The height f of the limiting step 111 and the two layers of encapsulation film 2t satisfy f / 2t ≥ 0.83, so as to prevent the height of the limiting step 111 from being too small, ensure the total thickness of the two layers of encapsulation film 21 after heat sealing, avoid over-pressing resulting in over-melting of the encapsulation film 21, ensure the bonding force between the PP layer and the non-PP layer of the encapsulation film, avoid peeling between the PP layer and the non-PP layer during the use of the battery cell 2, and ensure the sealing performance at the tab 22 of the battery cell 2; at the same time, the height f of the limiting step 111 and the two layers of encapsulation film 2t satisfy f / 2t ≤ 0.9. Such a setting can prevent the height of the limiting step 111 from being too large, prevent the thickness of the two layers of encapsulation film 21 from being too large after heat sealing, ensure sufficient hot pressing of the encapsulation film 21, avoid insufficient hot pressing strength, ensure the encapsulation strength between the two layers of encapsulation film 21 after heat sealing, and ensure the sealing performance at the tab 22 of the battery cell 2.

[0042] Design top-sealing toolings with different heights f of the limiting step 111 and battery cells with different thicknesses t of the encapsulation film, conduct vibration tests on the battery cells and observe the states of the battery cells. The test results are shown in Table 1.

[0043] Table 1

[0044]

[0045] As can be seen from Examples 1 to 5 in Table 1, when the height f of the limiting step 111 and the thickness t of the single-layer encapsulation film 21 satisfy 0.83 ≤ f / 2t ≤ 0.9, the state of the battery cell is good after the vibration test. From Comparative Example 1, it can be seen that when f / 2t > 0.9, due to the excessive height of the limiting step 111, the top-sealing tooling 1 cannot effectively hot-press the two-layer encapsulation film 21, the hot-pressing strength is insufficient, the thickness of the two-layer encapsulation film after hot-pressing is relatively thick, and the two-layer encapsulation film 21 peels off at the plastic-sealed part, resulting in battery cell leakage; from Comparative Example 2, it can be seen that when f / 2t < 0.83, the height of the limiting step 111 is too small, the thickness of the two-layer encapsulation film after hot-pressing is too small, overpressure and over-melting occur, the bonding force between the PP layer and the non-PP layer of the encapsulation film is insufficient, and the PP layer and the non-PP layer of the encapsulation film in the encapsulation area on both sides of the tab peel off, resulting in seal failure and leakage.

[0046] In some embodiments, the thickness t of the single-layer encapsulation film 21 satisfies 0.1 mm ≤ t ≤ 3 mm, and 0.2 mm ≤ f ≤ 6 mm.

[0047] When the pressure plate 12 presses down, due to the assembly tolerance, a shearing force will be generated on the positioning post 112. If the diameter of the positioning post 112 is too small, its strength will be insufficient and it is easy to break when subjected to the shearing force; if the diameter of the positioning post 112 is too large, it will cause waste of materials and space. To avoid these problems, in some alternative embodiments, as Figures 3 to 6 shown, the positioning post 112 is cylindrical, the diameter of the positioning post 112 is d1, and 4 mm ≤ d1 ≤ 50 mm. The positioning post 112 is cylindrical, and correspondingly the positioning hole 121 is a circular hole. The diameter d1 of the positioning post 112 satisfies 4 mm ≤ d1 ≤ 50 mm, so that the diameter of the positioning post 112 can be controlled within a suitable size to ensure its structural strength, and at the same time, it can avoid waste of materials and space caused by the too large diameter of the positioning post 112.

[0048] In other embodiments, the cross-section of the positioning post 112 can also be rectangular, triangular, elliptical, etc.

[0049] As Figure 4 shown, during heat sealing, the depth h of the positioning post 112 inserted into the positioning hole 121. If the value of h is too small, there is a risk of slippage at the positioning part of the pressure plate 12 and the support plate 11 when being pressed up and down; if the value of h is too large, it will cause waste of materials and space. Therefore, in some embodiments, h is made to satisfy 3 mm ≤ h ≤ 50 mm, so that the depth h of the positioning post 112 inserted into the positioning hole 121 can be controlled within a suitable range, ensuring the depth of the positioning post 112 inserted into the positioning hole 121, avoiding slippage at the positioning part of the pressure plate 12 and the support plate 11 when being pressed up and down, and ensuring the positioning effect of the positioning post 112, so as to effectively hot-press the encapsulation film 21; at the same time, it can also reduce waste of materials and space and improve the space utilization rate of the top-sealing tooling 1.

[0050] In some alternative embodiments, the limiting step 111 is provided on the support plate 11, the positioning post 112 is provided on the top of the limiting step 111, and the positioning hole 121 is provided on the pressing plate 12. The positioning hole 121 may be provided in a through-hole form penetrating the pressing plate 12 in the up-and-down direction, or may be provided as a blind hole without penetrating the pressing plate 12.

[0051] As Figure 1 and Figure 3 shown, in some embodiments, a positioning post 112 is provided at each end of the support plate 11 in the length direction. The number of the positioning posts 112 can be adjusted according to the size of the positioning posts 112 and the hot pressing pressure. When the cross-sectional area of the positioning post 112 is relatively large, one positioning post 112 or a smaller number of positioning posts 112 can be provided. When the cross-sectional area of the positioning post 112 is relatively small, more than three positioning posts 112 can be provided. As the hot pressing pressure increases, the number of the positioning posts 112 can be correspondingly increased, and the plurality of positioning posts 112 are arranged at intervals along the length direction of the support plate 11.

[0052] As Figure 5 and Figure 6 shown, in some embodiments, a first chamfered inclined surface 1121 is provided on the outer peripheral wall of the end of the positioning post 112 away from the limiting step 111. The width in the horizontal direction between the end of the first chamfered inclined surface 1121 facing the center of the positioning post 112 and the outer peripheral wall of the root of the positioning post 112 is w, and 0.2 mm ≤ w ≤ d1 / 3. When the pressing plate 12 is butted against the support plate 11, in the case of equipment tolerances, the support plate 11 can conveniently insert the positioning post 112 into the positioning hole 121 through the first chamfered inclined surface 1121, facilitating quick positioning. And the width w of the first chamfered inclined surface 1121 extending in the horizontal direction satisfies 0.2 mm ≤ w ≤ d1 / 3. Such a setting can avoid the inclination angle of the first chamfered inclined surface 1121 being too small, ensuring its guiding effect. At the same time, it can prevent w from being too large, resulting in too large an inclination angle of the first chamfered inclined surface 1121, preventing the top of the positioning post 112 from being too sharp, avoiding damage to the pressing plate 12 and the operator, and ensuring the safety when operating the jacking tooling.

[0053] As Figure 5As shown, the included angle between the first chamfered inclined surface 1121 and the end face of the positioning post 112 is g. If the angle g is too large, the inclination angle of the first chamfered inclined surface 1121 is too large; if the angle g is too small, the inclination angle of the first chamfered inclined surface 1121 is too small. Whether the inclination angle of the first chamfered inclined surface 1121 is too large or too small will affect its guiding effect. Therefore, in some embodiments, the included angle g between the first chamfered inclined surface 1121 and the end face of the positioning post 112 satisfies 100° ≤ g ≤ 150°. In this way, the angle g and the inclination angle of the first chamfered inclined surface 1121 can be controlled within a suitable range, which can ensure the guiding effect of the first chamfered inclined surface 1121 and ensure the quick docking of the positioning post 112 and the positioning hole 121.

[0054] As Figure 4 and Figure 5 shown, in some embodiments, a second chamfered inclined surface 1211 is provided at the orifice of the positioning hole 121. Along the height direction of the top sealing tooling, the distance between the end of the second chamfered inclined surface 1211 facing the inside of the positioning hole 121 and the end face of the positioning hole 121 is C. The second chamfered inclined surface 1211 facilitates the sliding of the positioning post 112 into the positioning hole 121. If the value of C is too small, the inclination angle of the second chamfered inclined surface 1211 is too small; if the value of C is too large, the inclination angle of the second chamfered inclined surface 1211 is too large. Whether the inclination angle of the second chamfered inclined surface 1211 is too small or too large is not conducive to its guiding function. Therefore, in some embodiments, the distance C between the end of the second chamfered inclined surface 1211 facing the inside of the positioning hole 121 and the end face of the positioning hole 121 satisfies 0.2 mm ≤ C ≤ 5 mm. Such a setting can control the inclination angle of the second chamfered inclined surface 1211 within a suitable range and facilitate the sliding of the positioning post 112 into the positioning hole 121.

[0055] In some embodiments, the inclination angle of the second chamfered inclined surface 1211 relative to the set surface is 45°.

[0056] As Figures 4 to 6 shown, in some embodiments, relief grooves are provided on the pressing plate 12 inside the positioning hole 121 and the supporting plate 11 inside the positioning post 112. The positioning post 112 is located at the end of the supporting plate 11, and a supporting post 113 is formed at the end of the supporting plate 11. A limiting step 111 is provided on the top surface of the supporting post 113. The horizontal distance between the outer peripheral wall of the positioning post 112 and the outer peripheral wall of the supporting post 113 is L, and L ≥ 2 mm. Such a setting can ensure that there is a sufficient area of the supporting post 113 around the outer periphery of the positioning post 112, can ensure the supporting area of the supporting post 113, and thus can ensure the support of the supporting post 113 for the positioning post 112, avoid dimensional deformation of the positioning post 112 or the limiting step 111 after multiple press-fittings, can ensure the height of the limiting step 111, and thus can ensure that the thickness of the encapsulation film 21 is controlled within a suitable range after heat sealing.

[0057] In some embodiments, such as Figures 4 to 6 shown, both the support column 113 and the limiting step 111 are cylindrical. The limiting step 111 and the support column 113 are coaxially arranged and have the same diameter. The positioning column 112 is arranged in the middle of the limiting step 111. The diameter of the support column 113 is d2, and (d2 - d1) / 2 ≥ 2 mm. Such a setting enables the support column 113 to be held in the middle of the limiting step 111 and the support column 113. At the same time, the diameter of the support column 113 is larger than that of the positioning column 112, which can ensure the support of the support column 113 for the limiting step 111 and the positioning column 112.

[0058] Such as Figure 6 shown, the limiting step 111 and the support column 113 are integrally formed. The area above the top surface of the support column 113 serves as the limiting step 111. The bottom surface of the limiting step 111 is flush with the top surface of the support plate 11 for supporting the encapsulation film 21 area, that is, the area between the top surface of the limiting step 111 and the top surface of the support plate 11 in the inner area of the avoidance groove is the limiting step 111.

[0059] According to an embodiment of the present invention, on the other hand, a battery cell 2 is further provided, which is top-sealed by using the top-sealing tooling 1 of the above embodiment.

[0060] When the battery cell 2 of this structure is top-sealed, first place the encapsulation edge of the battery cell 2 on the support plate 11, move the pressing plate 12 downward to press against the upper part of the encapsulation edge, and insert the positioning column 112 into the positioning hole 121 to guide the downward movement of the pressing plate 12. When the bottom surface of the pressing plate 12 or the top surface of the support plate 11 touches the limiting step 111, the pressing plate 12 stops pressing down. The limiting step 111 limits the pressing plate 12, and the downward pressing stroke of the pressing plate 12 can be accurately controlled; the height f of the limiting step 111 and the two layers of encapsulation film 2t satisfy f / 2t ≥ 0.83. This can prevent the height of the limiting step 111 from being too small, ensure the total thickness of the two layers of encapsulation film 21 after heat sealing, avoid overpressure causing the encapsulation film 21 to overmelt, ensure the bonding force between the PP layer and the non-PP layer of the encapsulation film, avoid the peeling of the PP layer and the non-PP layer during the use of the battery cell 2, and ensure the sealing performance at the tab 22 of the battery cell 2; at the same time, the height f of the limiting step 111 and the two layers of encapsulation film 2t satisfy f / 2t ≤ 0.9. Such a setting can prevent the height of the limiting step 111 from being too large, prevent the thickness of the two layers of encapsulation film 21 from being too large after heat sealing, ensure sufficient heat pressing of the encapsulation film 21, avoid insufficient heat pressing strength, ensure the encapsulation strength between the two layers of encapsulation film 21 after heat sealing, ensure the sealing performance at the tab 22 of the battery cell 2, and ensure the safety performance of the battery cell 2.

[0061] The battery cell 2 includes an encapsulation film 21, a tab 22, and an insulating member 23, such as Figure 9As shown, the insulating member 23 is provided outside the tab 22, and the tab 22, the insulating member 23, and the encapsulation film 21 are located between the support plate 11 and the pressing plate 12 for top-sealing encapsulation.

[0062] In some embodiments, the encapsulation film 21 includes an aluminum-plastic film, the insulating member 23 includes tab glue, the tab 22 includes a positive tab and a negative tab, and the positive tab and the negative tab are oppositely provided at both ends in the length direction of the battery cell 2.

[0063] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, including the above-mentioned battery cell 2.

[0064] For the battery pack with this structure, the battery cell 2 therein is heat-sealed by the top-sealing tooling 1 of the above embodiment, and the height f of the limiting step 111 satisfies 0.83 ≤ f / 2t ≤ 0.9 with respect to the two layers of encapsulation film 2t. This can ensure the total thickness of the two layers of encapsulation film 21 after heat-sealing, avoid over-melting of the encapsulation film 21 caused by overpressure, ensure the bonding force between the PP layer and the non-PP layer of the encapsulation film, and ensure the sealing performance at the tab 22 of the battery cell 2; at the same time, it can prevent the thickness of the two layers of encapsulation film 21 from being too large after heat-sealing, ensure sufficient heat pressing of the encapsulation film 21, avoid insufficient heat pressing strength, ensure the encapsulation strength between the two layers of encapsulation film 21 after heat-sealing, ensure the sealing performance at the tab 22 of the battery cell 2, and ensure the safety performance of the battery cell 2 and the battery pack.

[0065] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A top sealing tool, characterized in that: include: Support plate; A pressing plate is suitable for being pressed on top of the support plate; a limiting step is provided on at least one side of the length direction of the top surface of the support plate and the bottom surface of the pressing plate, and a positioning column is provided on the limiting step; the height of the limiting step is f, the thickness of the single-layer packaging film of the battery cell is t, the units of f and t are mm, 0.83≤f / 2t≤0.9; the support plate or the pressing plate is provided with a positioning hole cooperating with the positioning column, and the positioning column is inserted into the positioning hole.

2. The top sealing tool according to claim 1, characterized in that: The positioning column is cylindrical, and the diameter of the positioning column is d1, 4mm≤d1≤50mm.

3. The top sealing tool according to claim 1 or 2, characterized in that: The depth of the positioning column inserted into the positioning hole is h, 3mm≤h≤50mm.

4. The top sealing tool according to claim 2, characterized in that: The outer peripheral wall of the positioning column away from the limiting step is provided with a first chamfered surface, and the horizontal width between the end of the first chamfered surface facing the center of the positioning column and the root outer peripheral wall of the positioning column is w, 0.2mm≤w≤d1 / 3.

5. The top sealing tool according to claim 4, characterized in that: The included angle between the first chamfered slope and the end surface of the positioning column is g, and 100°≤g≤150°.

6. The top sealing tool according to claim 1 or 2, characterized in that: A second chamfered surface is provided at the opening of the positioning hole, and along the height direction of the top sealing tooling, the distance between one end of the second chamfered surface facing the inner side of the positioning hole and the end face of the positioning hole is C, 0.2mm≤C≤5mm.

7. The top sealing tool according to claim 2, characterized in that: The support plate or the pressure plate is provided with a support column, the limiting step is provided on the support column, and the horizontal distance between the outer peripheral wall of the positioning column and the outer peripheral wall of the support column is L, and L≥2mm.

8. The top sealing tool according to claim 7, characterized in that: The support column and the limiting step are both cylindrical, the limiting step and the support column are coaxially arranged and have the same diameter, the positioning column is arranged in the middle of the limiting step, and the diameter of the support column is d2, (d2-d1) / 2≥2mm.

9. A battery cell, characterized in that: The top sealing package is performed by using the top sealing tool according to any one of claims 1 to 8.

10. A battery pack, characterized in that: Comprising the battery cell as claimed in claim 9.

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