Battery cell and battery pack

Abstract

The utility model relates to the technical field of battery cells, and discloses a battery cell and a battery pack, and the battery cell comprises a pole group, a packaging film and a pole lug, according to the battery cell with the structure, the corner cutting edges are arranged at the four corners of the packaging film so as to change the right-angle structures at the four corners of the packaging film, the right-angle structures can be prevented from being formed at the four corners of the packaging film after the packaging film is folded, and the right-angle structures can be prevented from scratching the packaging film of the adjacent battery cell in the battery cell transferring process, so that the sealing performance of the battery cell can be ensured; meanwhile, an operator can be prevented from being scratched by the right-angle structure, and the safety in the battery cell transferring process can be improved. The edge sealing area on the inner side of the corner cutting edge area is parallel to the corner cutting edge, and the width of the edge sealing area on the inner side of the corner cutting edge is greater than or equal to that of the edge sealing area on the inner side of the non-corner cutting edge of the packaging film, so that the heat sealing effect of the packaging film in the corner cutting edge area can be ensured, the packaging strength of the corner cutting edge area is ensured, and the overall sealing performance of the battery cell can be ensured.

Description

Technical Field

[0001] This utility model relates to the field of battery cell technology, specifically to a battery cell and battery pack. Background Technology

[0002] A pouch cell consists of electrode assemblies and a sealing film. The sealing film protects the cell and ensures its airtightness. The sealing film has grooves stamped into it, and the electrode assemblies are placed within these grooves. The sealing film is folded along its centerline so that the two layers are positioned opposite each other. The inner layer of the sealing film is a PP layer. The two PP layers are then hot-pressed together and allowed to melt and fuse for a certain period, followed by cooling to bond them together and achieve the purpose of sealing the electrode assemblies. After sealing, to reduce the space occupied by the sealing film, the outer edge of the electrode assemblies is folded. However, in existing cells, the four corners of the folded sealing film are sharp right angles. During cell transport, these right angles can easily scratch the sealing films of adjacent cells, affecting the cell's airtightness. Utility Model Content

[0003] In view of this, the present invention provides a battery cell and battery pack to solve the problem that the four corners of the packaging film of the soft-pack battery cell in the prior art are all right-angle structures, which makes it easy to damage the packaging film of adjacent battery cells during transportation.

[0004] In a first aspect, this utility model provides a battery cell, comprising:

[0005] pole group;

[0006] An encapsulation film has a receiving groove on it, the electrode assembly is disposed in the receiving groove, and the encapsulation film wraps around the electrode assembly; the encapsulation film outside the electrode assembly is heat-sealed to form a sealing edge area, and the four corners of the encapsulation film are provided with chamfered edges, the sealing edge area inside the chamfered edges is arranged parallel to the chamfered edges, and the width of the sealing edge area inside the chamfered edges is greater than or equal to the width of the sealing edge area inside the non-chamfered edges of the encapsulation film;

[0007] The tab has one end electrically connected to the electrode group and the other end located outside the encapsulation film.

[0008] Beneficial effects: This cell structure, by setting chamfered edges at the four corners of the encapsulation film, changes the right-angle structure at the four corners of the encapsulation film. After folding the encapsulation film, it avoids forming right-angle structures at the four corners. During cell transportation, it prevents right-angle structures from scratching the encapsulation films of adjacent cells, thus ensuring the cell's sealing performance. It also prevents right-angle structures from scratching operators, improving safety during cell transportation. Furthermore, the sealing area inside the chamfered edge region is parallel to the chamfered edge, and the width of the sealing area inside the chamfered edge is greater than or equal to the width of the sealing area without chamfered edges. This design ensures the heat-sealing effect of the encapsulation film in the chamfered edge region, maintaining the encapsulation strength in the chamfered edge region, thereby ensuring the overall sealing performance of the cell.

[0009] In one optional embodiment, the encapsulation films on both sides of the electrode group in the width direction are bent to form a folded edge structure, and the included angle between the folded edge structure and the edge of the chamfered edge is α, where 15°≤α≤75°.

[0010] Beneficial effect: This setting ensures that the chamfered edges have a sufficient tilt angle, so that the right-angled structures at the four corners of the encapsulation film are fully tilted toward the inside of the battery cell, preventing the right-angled structures from damaging the encapsulation film during transportation.

[0011] In one optional embodiment, the distance between the end of the chamfered edge away from the wide side of the battery cell and the edge of the wide side of the battery cell is L1, where 0.5mm≤L1≤10mm.

[0012] Beneficial effects: 0.5mm≤L1, this setting can ensure that the chamfered edge has a sufficient tilt angle and ensure the area of ​​the chamfered edge region; L1≤10mm, this setting can avoid excessive removal of the encapsulation film and waste of materials.

[0013] In one optional embodiment, the distance between the end of the chamfered edge facing the wide side of the battery cell and the edge of the long side of the battery cell is L2, where 0.5mm≤L2≤10mm.

[0014] Beneficial effects: 0.5mm≤L2, this setting can ensure that the chamfered edge has a sufficient tilt angle to ensure the area of ​​the chamfered edge region; L2≤10mm, this setting can avoid excessive removal of the encapsulation film, thus avoiding material waste.

[0015] In one optional embodiment, the width of the sealing area is W, where 1.5mm ≤ W ≤ 5mm.

[0016] Beneficial effects: The width of the sealing area affects the encapsulation strength. If the sealing area is too small, the encapsulation strength cannot be guaranteed, and the encapsulation film is prone to cracking when it is under stress or when gas is generated inside the cell. If the sealing area is too large, a larger encapsulation film needs to be reserved at the outer edge of the electrode assembly, which will result in a waste of encapsulation film material. A larger sealing area also requires more energy to be consumed during the heat sealing process. Therefore, it is necessary to ensure that 1.5mm ≤ W to guarantee the width of the sealing area and the encapsulation strength of the sealing area. At the same time, it is necessary to ensure that W ≤ 5mm to avoid the waste of encapsulation film material and heat sealing energy caused by a large sealing area.

[0017] In one alternative implementation, the outer edge of the sealing area is provided with a non-heat-sealed zone.

[0018] Beneficial effects: During the heat sealing process, the PP layer inside the encapsulation film is prone to adhesive overflow during melting. If the sealing area extends to the edge of the encapsulation film, the overflowing adhesive will be exposed on the outside of the battery cell, affecting its appearance. To solve this problem, a certain width of non-heat-sealing area is reserved at the outer edge of the sealing area. When adhesive overflow occurs during heat sealing, the adhesive overflows into the non-heat-sealing area, which then shields the overflowing adhesive, preventing the overflowing adhesive clumps from affecting the battery cell's appearance. Furthermore, it prevents the overflowing adhesive clumps from damaging the encapsulation film during micro-drop tests.

[0019] In one optional implementation, the width of the non-heat-sealed area is W1, where 0.5mm ≤ W1 ≤ 2mm.

[0020] Beneficial effects: This setting ensures that the non-heat-sealed area has sufficient width, which can effectively prevent the overflow of adhesive clumps. At the same time, it can prevent the non-heat-sealed area from being too wide, which would waste the encapsulation film material. It can also prevent the non-heat-sealed area from being too wide and occupying too much space, which is conducive to ensuring the volumetric energy density of the battery cell.

[0021] In one alternative embodiment, the tabs include a positive tab and a negative tab, which are disposed opposite to each other on the two wide sides of the battery cell.

[0022] In one alternative embodiment, the tabs include a positive tab and a negative tab, which are disposed on one of the wide sides of the battery cell.

[0023] Secondly, this utility model also provides a battery pack, including the battery cell described in any of the above descriptions. The battery pack includes the battery cell and has the same technical effects as the battery cell, which will not be repeated here. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a three-dimensional structural diagram of a battery cell according to an embodiment of the present utility model;

[0026] Figure 2 for Figure 1 Enlarged view of part A in the middle;

[0027] Figure 3 This is a side view of a battery cell according to an embodiment of the present utility model;

[0028] Figure 4 This is a top view of a battery cell according to an embodiment of the present utility model;

[0029] Figure 5 for Figure 4 Enlarged view of part B in the middle;

[0030] Figure 6 This is a top view of a battery cell without its corners cut, according to an embodiment of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Electrode assembly; 2. Encapsulation film; 21. Sealing area; 22. Chamfered edge; 23. Folded edge structure; 24. Non-heat-sealed area; 3. Positive electrode tab; 4. Negative electrode tab. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0034] The following is combined with Figures 1 to 6 The following describes embodiments of the present invention.

[0035] According to an embodiment of the present invention, a battery cell is provided, comprising an electrode assembly 1, an encapsulation film 2, and tabs. The encapsulation film 2 has a receiving groove, the electrode assembly 1 is disposed within the receiving groove, and the encapsulation film 2 wraps around the electrode assembly 1. The encapsulation film 2 outside the electrode assembly 1 is heat-sealed to form a sealing edge area 21. The four corners of the encapsulation film 2 are provided with chamfered edges 22. The sealing edge area 21 inside the chamfered edges 22 is arranged parallel to the chamfered edges 22, and the width of the sealing edge area 21 inside the chamfered edges 22 is greater than or equal to the width of the sealing edge area 21 inside the non-chamfered edges of the encapsulation film. One end of the tab is electrically connected to the electrode assembly 1, and the other end is disposed outside the encapsulation film 2.

[0036] This battery cell structure, by setting chamfered edges 22 at the four corners of the encapsulation film 2, changes the right-angle structure at the four corners of the encapsulation film 2. After the encapsulation film 2 is folded, it avoids forming right-angle structures at the four corners. During the battery cell transfer process, it can prevent right-angle structures from scratching the encapsulation film 2 of adjacent battery cells, thereby ensuring the battery cell's sealing performance. At the same time, it can also prevent right-angle structures from scratching operators, which is beneficial to improving the safety of the battery cell transfer process. Furthermore, the sealing area 21 inside the chamfered edge 22 is parallel to the chamfered edge 22, and the width of the sealing area 21 inside the chamfered edge 22 is greater than or equal to the width of the sealing area 21 inside the encapsulation film 2 where the chamfered edge 22 is not set. This setting can ensure the heat sealing effect of the encapsulation film 2 in the chamfered edge 22 area, ensure the encapsulation strength in the chamfered edge 22 area, and thus ensure the overall sealing performance of the battery cell.

[0037] In some embodiments, such as Figure 4 As shown, the encapsulation films 2 on both sides of the width direction of the electrode group 1 are bent to form a folded edge structure 23. The included angle between the folded edge structure 23 and the edge of the chamfered edge 22 is α, 15°≤α≤75°. This setting can ensure that the chamfered edge 22 has a sufficient tilt angle, so that the right-angled structure at the four corners of the encapsulation film 2 is fully tilted towards the inside of the cell, preventing the right-angled structure from damaging the encapsulation film 2 during transportation.

[0038] like Figure 1 and Figure 4 As shown, the x-axis is called the width direction of the battery cell, the y-axis is called the length direction of the battery cell, and the z-axis is called the thickness direction of the battery cell. In some embodiments, the distance between the end of the chamfered edge 22 away from the wide side of the battery cell and the edge of the wide side of the battery cell is L1, 0.5mm≤L1≤10mm. 0.5mm≤L1 ensures that the chamfered edge 22 has a sufficient tilt angle to guarantee the area of ​​the chamfered edge 22 region; L1≤10mm avoids excessive removal of the encapsulation film 2, thus preventing material waste.

[0039] Similarly, such as Figure 4As shown, the distance between the end of the chamfered edge 22 facing the wide side of the battery cell and the edge of the long side of the battery cell is L2, 0.5mm≤L2≤10mm. 0.5mm≤L2 ensures that the chamfered edge 22 has a sufficient tilt angle to guarantee the area of ​​the chamfered edge 22 region; L2≤10mm avoids excessive removal of the encapsulation film 2, thus preventing material waste.

[0040] In some embodiments, such as Figure 4 and Figure 5 As shown, the width of the sealing area 21 is W, 1.5mm≤W≤5mm. The width of the sealing area 21 affects the encapsulation strength. If the width of the sealing area 21 is too small, the encapsulation strength cannot be guaranteed, and the encapsulation film 2 is prone to cracking when the encapsulation film 2 is subjected to force or gas is generated inside the cell. If the width of the sealing area 21 is large, a larger encapsulation film 2 needs to be reserved at the outer edge of the electrode group 1, which will result in a waste of encapsulation film 2 material.

[0041] When the sealing area 21 is wide, a large amount of energy is required during the heat sealing process. Therefore, W is kept to be less than or equal to 1.5mm to ensure the width of the sealing area 21 and the sealing strength of the sealing area 21; at the same time, W is kept to be less than or equal to 5mm to avoid wasting the material of the sealing film 2 and the heat sealing energy due to the large width of the sealing area 21.

[0042] like Figure 4 and Figure 5 As shown, in some embodiments, the width of the sealing area 21 of the chamfered edge 22 region is the same as the width of the sealing area 21 inside the non-chamfered edge 22. This setting can ensure the sealing strength of the chamfered edge 22 region.

[0043] like Figure 6 As shown, in this embodiment, before the corner of the encapsulation film 2 is cut, the heat-sealing area is increased in the area of ​​the corner to be cut 22, and the heat-sealing area of ​​this area is tilted toward the inside of the cell, so as to ensure that the corner 22 area has a sufficiently wide sealing area 21 after the corner is cut, and to ensure that the corner 22 area meets the encapsulation strength requirements.

[0044] In other embodiments, the width of the sealing area 21 of the chamfered edge 22 region is greater than the width of the sealing area 21 on the inside of the non-chamfered edge, which can further improve the sealing strength of the chamfered edge 22 region.

[0045] like Figure 5As shown, in some embodiments, a non-heat-sealed area 24 is provided around the outer edge of the sealing area 21. During the heat-sealing process of the encapsulation film 2, the PP layer of the inner layer of the encapsulation film 2 is prone to overflow during the melting process. If the sealing area 21 extends to the edge of the encapsulation film 2, the overflowed adhesive will be exposed on the outside of the battery cell, affecting the appearance of the battery cell. To solve this problem, a non-heat-sealed area 24 of a certain width is reserved at the outer edge of the sealing area 21. After the overflow occurs during the heat-sealing process, the adhesive overflows into the non-heat-sealed area 24. The non-heat-sealed area 24 blocks the overflowed adhesive, preventing the overflowing adhesive clumps from leaking out and affecting the appearance of the battery cell. It can also prevent the overflowing adhesive clumps from damaging the encapsulation film 2 in the micro-drop test.

[0046] Optionally, in some embodiments, the width of the non-heat-sealed area 24 is W1, where 0.5mm≤W1≤2mm. This setting ensures that the non-heat-sealed area 24 has sufficient width, thereby effectively preventing the overflow of adhesive residue. It also prevents the non-heat-sealed area 24 from being too wide, which would waste the material of the encapsulation film 2. Furthermore, it prevents the non-heat-sealed area 24 from occupying too much space due to its excessive width, which is beneficial for ensuring the volumetric energy density of the battery cell.

[0047] In some embodiments, such as Figure 1 , Figure 4 and Figure 6 As shown, the electrode tabs include a positive electrode tab 3 and a negative electrode tab 4, which are positioned opposite each other on the two wide sides of the battery cell. This dual-sided electrode arrangement provides a shorter current transmission path, thereby improving the cell's performance and charging speed. Furthermore, the dual-sided electrode arrangement helps to balance the current distribution within the cell, reducing internal resistance and heat generation.

[0048] In other embodiments, the tabs include a positive tab 3 and a negative tab 4, which are located on one of the wider sides of the battery cell. Having tabs on the same side of the battery cell results in a simple structure, low manufacturing cost, and reduced space occupied by external tabs, thereby increasing the volumetric energy density of the battery cell.

[0049] Optionally, in some embodiments, the positive electrode tab 3 includes an inner positive electrode tab and an outer positive electrode tab, and the negative electrode tab 4 includes an inner negative electrode tab and an outer negative electrode tab. The inner positive electrode tab is located inside the encapsulation film 2 and one end of it is welded to the electrode assembly 1. One end of the outer positive electrode tab is located inside the encapsulation film 2, and the other end extends out of the encapsulation film 2. The end of the outer positive electrode tab located inside the encapsulation film 2 is welded to the inner positive electrode tab. Similarly, the inner negative electrode tab is located inside the encapsulation film 2 and one end of it is welded to the electrode assembly 1. One end of the outer negative electrode tab is located inside the encapsulation film 2, and the other end extends out of the encapsulation film 2. The end of the outer negative electrode tab located inside the encapsulation film 2 is welded to the inner negative electrode tab.

[0050] In some embodiments, the encapsulation film 2 includes an aluminum-plastic film.

[0051] According to an embodiment of the present invention, another aspect provides a battery pack including the aforementioned battery cell.

[0052] In this battery pack structure, the internal cells have chamfered edges 22 at their four corners, altering the right-angle structure at the corners of the encapsulation film 2. During cell transport, this prevents the right-angle structure from scratching the encapsulation film 2 of adjacent cells, thus ensuring the cell's sealing performance. It also prevents the right-angle structure from injuring operators, improving safety during cell transport. Furthermore, the sealing area 21 inside the chamfered edge 22 is parallel to the chamfered edge 22, and the width of the sealing area 21 inside the chamfered edge 22 is greater than or equal to the width of the sealing area 21 inside the encapsulation film 2 without the chamfered edge 22. This design ensures the heat-sealing effect of the encapsulation film 2 in the chamfered edge 22 area, guaranteeing the encapsulation strength in this area and thus ensuring the overall sealing performance of the cell, improving the battery pack's safety performance.

[0053] Although 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 all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, include: pole group; An encapsulation film has a receiving groove on it, the electrode assembly is disposed in the receiving groove, and the encapsulation film wraps around the electrode assembly; the encapsulation film outside the electrode assembly is heat-sealed to form a sealing edge area, and the four corners of the encapsulation film are provided with chamfered edges, the sealing edge area inside the chamfered edges is arranged parallel to the chamfered edges, and the width of the sealing edge area inside the chamfered edges is greater than or equal to the width of the sealing edge area inside the non-chamfered edges of the encapsulation film; The tab has one end electrically connected to the electrode group and the other end located outside the encapsulation film.

2. The battery cell according to claim 1, characterized in that, The encapsulation films on both sides of the electrode group in the width direction are bent to form a folded edge structure, and the included angle between the folded edge structure and the edge of the chamfered edge is α, 15°≤α≤75°.

3. The battery cell according to claim 1 or 2, characterized in that, The distance between the end of the chamfered edge that is away from the wide side of the battery cell and the edge of the wide side of the battery cell is L1, where 0.5mm≤L1≤10mm.

4. The battery cell according to claim 1 or 2, characterized in that, The distance between the end of the chamfered edge facing the wide side of the battery cell and the edge of the long side of the battery cell is L2, where 0.5mm≤L2≤10mm.

5. The battery cell according to claim 1 or 2, characterized in that, The width of the edge sealing area is W, where 1.5mm ≤ W ≤ 5mm.

6. The battery cell according to claim 1 or 2, characterized in that, The outer edge of the sealing area is provided with a non-heat-sealed zone.

7. The battery cell according to claim 6, characterized in that, The width of the non-heat-sealed area is W1, where 0.5mm ≤ W1 ≤ 2mm.

8. The battery cell according to claim 1 or 2, characterized in that, The electrode tabs include a positive electrode tab and a negative electrode tab, which are disposed opposite to each other on the two wide sides of the battery cell.

9. The battery cell according to claim 1 or 2, characterized in that, The electrode includes a positive electrode and a negative electrode, which are disposed on one of the wide sides of the battery cell.

10. A battery pack, characterized in that, The battery cell includes any one of claims 1 to 9.

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