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 and a packaging film, wherein the side edge of the pole group is provided with a pole lug; the packaging film is coated outside the pole group, the packaging film outside the circumferential outer edge of the pole group is subjected to heat sealing to form a heat sealing area, and a non-heat sealing area is arranged outside the heat sealing area on the side where the tab is located. According to the battery cell with the structure, the non-heat-sealing area is arranged outside the heat-sealing area on the side where the tabs are located, and the width W2 of the non-heat-sealing area meets the condition that 1 mm < = W2 < W1, so that the non-heat-sealing area has enough width, overflow micelles on the side of the tabs are prevented from leaking, and the appearance of the packaged battery cell is improved; meanwhile, the overflow micelles are shielded in the non-heat-sealing area, so that the overflow micelles can be effectively prevented from causing damage to the packaging film in the micro-drop experiment process; in addition, W2 is smaller than W1, so that material waste caused by the fact that the width of the non-heat-sealing area is too wide can be avoided, and the situation that the occupied space of the packaging film is increased can be prevented.

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 includes an electrode assembly, a sealing film, and external tabs. The sealing film protects the electrode assembly. One end of the external tab is inside the sealing film, and the other end is outside. The end of the external tab inside the sealing film is electrically connected to the electrode assembly, while the other end is used for electrical connection to an external structure. During the assembly process of the sealing film and the electrode assembly, a receiving groove is first stamped at a designated position on the sealing film. The electrode assembly is placed in the receiving groove, and then the sealing film is folded and heat-sealed to complete the packaging of the electrode assembly.

[0003] The inner layer of the encapsulation film is made of PP. During the encapsulation process, the end cap is usually heated first, and then the end cap applies heat to the two layers of encapsulation film through force. When the PP layer of the inner layer of the encapsulation film reaches the specified temperature, the PP layer melts and the PP layers of the two encapsulation films stick together, thereby achieving heat sealing of the encapsulation film.

[0004] During the heat sealing process, some of the molten PP material flows to both sides of the end cap under the force of the end cap, forming excess glue clumps on both sides of the heat-sealing area of ​​the encapsulation film. These excess glue clumps affect the appearance of the encapsulated cell, and their exposure can cause the encapsulation film to break and fail during micro-drop tests. Utility Model Content

[0005] In view of this, the present invention provides a battery cell and battery pack to solve the problems in the prior art where excess glue from the battery cell leaks out of the encapsulation film, affecting the appearance of the battery cell and causing damage to the encapsulation film during micro-drop tests.

[0006] In a first aspect, this utility model provides a battery cell, comprising:

[0007] A pole group, wherein the pole group is provided with pole tabs on its side;

[0008] An encapsulation film is used to cover the electrode assembly. The encapsulation film outside the circumferential outer edge of the electrode assembly is heat-sealed to form a heat-sealed area. A non-heat-sealed area is provided outside the heat-sealed area on the side where the electrode tab is located. The width of the heat-sealed area is W1, and the width of the non-heat-sealed area is W2, where 1mm ≤ W2 < W1.

[0009] Beneficial effects: This cell structure has a non-heat-sealed area outside the heat-sealed area on the side where the tab is located, and the width W2 of the non-heat-sealed area satisfies 1mm≤W2<W1. This setting allows the non-heat-sealed area to have sufficient width to prevent excess glue from leaking out from the tab side, thereby improving the appearance of the cell after packaging. At the same time, the excess glue is blocked inside the non-heat-sealed area, which can effectively prevent the excess glue from causing damage to the encapsulation film during micro-drop tests. In addition, W2<W1, this setting can avoid the waste of material caused by the excessive width of the non-heat-sealed area, and can also prevent the encapsulation film from occupying too much space.

[0010] In one optional embodiment, an insulating element is further included, the insulating element being disposed between the tab and the encapsulation film; along the width direction of the heat-sealed region, the outer edge of the insulating element is located outside the non-heat-sealed region, and the inner edge of the insulating element is located inside the heat-sealed region.

[0011] Beneficial effects: After the battery cell is heat-sealed, the tabs need to be bent to connect with the tabs of other battery cells. During the bending process, the insulating component is located between the tab and the encapsulation film, which can prevent the sharp ends generated after the tab is bent from damaging the encapsulation film, ensure the sealing of the encapsulation film, and avoid the risk of short circuit.

[0012] In one optional embodiment, the width between the outer edge of the insulating element and the outer edge of the non-heat-sealed area is W3, where 2mm ≤ W3 ≤ 8mm.

[0013] Beneficial effects: This design allows for a sufficiently wide insulating component on the outer edge of the non-heat-sealed area, effectively preventing damage to the encapsulation film after the tabs are bent, while also preventing material waste caused by excessively wide insulating components.

[0014] In one optional embodiment, the width between the inner edge of the insulating element and the inner edge of the heat-sealing area is W4, where 2mm ≤ W4 ≤ 8mm.

[0015] Beneficial effects: This design allows for a sufficiently wide insulating component on the inner side of the heat-sealing zone, effectively preventing damage to the encapsulation film after the tabs are bent, while also preventing material waste caused by excessively wide insulating components.

[0016] In one alternative embodiment, the width of the insulating element is W, where 50% ≤ W1 / W ≤ 80%.

[0017] Beneficial effects: The sealing width is greater than or equal to half the width of the insulating component. This setting ensures sufficient sealing width between the insulating component and the encapsulation film, thereby guaranteeing the sealing strength and sealing effect at the tab. At the same time, W1 / W≤80% avoids the insulation component being too narrow on the outer edge of the non-heat-sealed area and the inner edge of the heat-sealed area due to the excessive width of the heat-sealed area. This ensures the protective effect of the insulating component on the encapsulation film after bending the tab.

[0018] In one alternative implementation, 60% ≤ W1 / W ≤ 80%.

[0019] In one optional embodiment, the two ends of the insulating member along its length are located outside the tab, the length of the insulating member is L, and the length of the tab is L1, where 3mm≤L-L1≤8mm.

[0020] Beneficial effect: This design allows the insulating component to wrap around the tab from both ends along its length, enabling the tab to form a good seal with the encapsulation film through the insulating component.

[0021] In one alternative implementation, 1.1 ≤ L / L1 ≤ 1.5.

[0022] In one alternative embodiment, the electrode tabs include a positive electrode tab and a negative electrode tab, which are disposed on opposite sides of the electrode assembly.

[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 schematic 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 schematic diagram showing the fit between the electrode tab and the insulating component.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Electrode assembly; 11. Positive tab; 12. Negative tab; 2. Encapsulation film; 21. Heat-sealed area; 22. Non-heat-sealed area; 3. Insulating component. Detailed Implementation

[0030] 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.

[0031] During the heat-sealing process, some of the molten PP material in the encapsulation film flows to both sides of the encapsulation head under the force of the end cap, forming excess glue clumps on both sides of the heat-sealing area of ​​the encapsulation film, causing the excess glue clumps to leak out of the encapsulation film. On the non-tab side, the excess glue clumps on the outside of the heat-sealing area are usually removed by cutting, but on the tab side, the presence of the tabs prevents cutting. Excess glue clumps on the tab side affect the appearance of the encapsulated cell, and exposed excess glue clumps can cause the encapsulation film to break and fail during micro-drop tests.

[0032] The following is combined with Figures 1 to 3 The following describes embodiments of the present invention.

[0033] According to an embodiment of the present invention, a battery cell is provided, comprising an electrode assembly 1 and an encapsulation film 2.

[0034] The electrode group 1 has tabs on its side; the encapsulation film 2 covers the electrode group 1, and the encapsulation film 2 outside the circumferential outer edge of the electrode group 1 is heat-sealed to form a heat-sealed area 21. A non-heat-sealed area 22 is provided outside the heat-sealed area 21 on the side where the tab is located. The width of the heat-sealed area 21 is W1, and the width of the non-heat-sealed area 22 is W2, where 1mm≤W2<W1.

[0035] In this battery cell structure, a non-heat-sealed area 22 is provided outside the heat-sealed area 21 on the side where the tab is located, and the width W2 of the non-heat-sealed area 22 satisfies 1mm≤W2<W1. This setting allows the non-heat-sealed area 22 to have sufficient width to prevent excess glue from leaking out from the tab side, thereby improving the appearance of the battery cell after packaging. At the same time, the excess glue is blocked inside the non-heat-sealed area 22, which can effectively prevent the excess glue from causing damage to the encapsulation film 2 during the micro-drop test. In addition, W2<W1, this setting can avoid the waste of material caused by the excessive width of the non-heat-sealed area 22, and can also prevent the encapsulation film 2 from occupying too much space.

[0036] In some optional embodiments, the battery cell further includes an insulating element 3, which is disposed between the tab and the encapsulation film 2. Along the width direction of the heat-sealed area 21, the outer edge of the insulating element 3 is located outside the non-heat-sealed area 22, and the inner edge of the insulating element 3 is located inside the heat-sealed area 21, that is, the width of the insulating element 3 is greater than the sum of the widths of the heat-sealed area 21 and the non-heat-sealed area 22. After the battery cell is heat-sealed, the tab needs to be bent to connect with the tabs of other battery cells. During the bending process, the insulating element 3 is located between the tab and the encapsulation film 2, which can prevent the sharp ends generated after the tab is bent from damaging the encapsulation film 2, ensure the sealing performance of the encapsulation film 2, and avoid the risk of short circuit.

[0037] In some embodiments, such as Figure 1 and Figure 2 As shown, the width between the outer edge of the insulating element 3 and the outer edge of the non-heat-sealed area 22 is W3, where 2mm≤W3≤8mm. This setting ensures that the outer edge of the non-heat-sealed area 22 has a sufficiently wide insulating element 3, which can effectively prevent damage to the encapsulation film 2 after the tab is bent, and at the same time prevent the insulating element 3 from being too wide, thus avoiding material waste.

[0038] In some embodiments, the width between the inner edge of the insulating member 3 and the inner edge of the heat-sealing area 21 is W4, where 2mm≤W4≤8mm. This arrangement ensures that the inner side of the inner edge of the heat-sealing area 21 has a sufficiently wide insulating member 3, which can effectively prevent damage to the encapsulation film 2 after the tab is bent, and at the same time prevent the insulating member 3 from being too wide, thus avoiding material waste.

[0039] One side of the insulating component 3 is bonded to the tab, and the other side faces the inner layer of the encapsulation film 2. During heat sealing, the heat sealing head transfers heat to the PP layer of the encapsulation film 2 and the outer layer of the insulating component 3. After the PP layer of the encapsulation film 2 and the outer layer of the insulating component 3 melt, mix, and cool, they bond the encapsulation film 2 and the insulating component 3 together. The ratio of the bonding width between the insulating component 3 and the encapsulation film 2 to the total width of the insulating component 3 affects the encapsulation strength of the encapsulation film 2. The bonding width between the insulating component 3 and the encapsulation film 2 is the heat sealing width. In some embodiments, the width of the insulating element 3 is W, 50% ≤ W1 / W ≤ 80%, and the heat-sealing width is greater than or equal to half the width of the insulating element 3. This setting ensures that there is sufficient encapsulation width between the insulating element 3 and the encapsulation film 2, thereby ensuring the encapsulation strength and sealing effect at the tab. At the same time, W1 / W ≤ 80% avoids the insulating element 3 being too narrow on the outer side of the non-heat-sealing area 22 and the inner side of the inner edge of the heat-sealing area 21 due to the excessive width of the heat-sealing area 21. This ensures the protective effect of the insulating element 3 on the encapsulation film 2 after bending the tab.

[0040] Preferably, in some embodiments, 60% ≤ W1 / W ≤ 80%, this setting can further optimize the encapsulation width between the insulating element 3 and the encapsulation film 2, and can improve the encapsulation strength at the tab.

[0041] During heat sealing, the insulating element 3 is heat-fused and bonded to the inner layer of the encapsulation film 2. The tab occupies a certain thickness, and two layers of insulating elements 3 are spaced apart on both sides of the tab's length. During heat sealing, the inner layer materials of the two insulating elements 3 facing each other melt and fuse to encapsulate and seal the tab. If the length of the insulating element 3 is the same as the length of the tab, or if its length is less than the length of the tab, it cannot effectively encapsulate and seal the tab. To avoid this problem, in some embodiments, the two ends of the insulating element 3 in the length direction are located outside the tab. The length of the insulating element 3 is L, and the length of the tab is L1, where 3mm ≤ L - L1 ≤ 8mm. This arrangement facilitates the insulating element 3 to encapsulate the tab from both ends in the length direction, allowing the tab to form a good seal with the encapsulation film 2 through the insulating element 3.

[0042] Optionally, in some embodiments, 1.1≤L / L1≤1.5, the length of the insulating member 3 is greater than the length of the tab, and the two ends of the insulating member 3 in the length direction are located outside the tab. The insulating member 3 can wrap around the tab from both ends in the length direction, which is beneficial to improving the sealing effect at the tab.

[0043] In some alternative embodiments, the tab is located at the middle of the length of the insulating member 3, and the insulating members 3 covering both sides of the tab are of the same length, which helps to ensure the sealing conditions on both sides of the length of the tab.

[0044] In some embodiments, the encapsulation film 2 includes an aluminum-plastic film, the outer layer of the insulating component 3 includes a PP layer, and both the inner layer of the encapsulation film 2 and the outer layer of the insulating component 3 are PP layers, which is more conducive to the synchronous heat melting of the inner layer of the encapsulation film 2 and the outer layer of the insulating component 3 during heat sealing, thus ensuring the heat sealing effect.

[0045] In some alternative embodiments, the insulating element 3 includes tab adhesive.

[0046] Alternatively, in some embodiments, such as Figure 1 As shown, the electrode tabs include a positive electrode tab 11 and a negative electrode tab 12, which are located on opposite sides of the electrode group 1. For example, the positive electrode tab 11 and the negative electrode tab 12 are located on both sides of the electrode group 1 in the width direction, and the battery cell has electrode tabs on both sides. This structure can provide a more uniform current distribution, thereby improving the performance and lifespan of the battery cell.

[0047] In other embodiments, the positive tab 11 and the negative tab 12 may also be located on one side of the electrode group 1. In this case, the battery cell has tabs on only one side. This arrangement can simplify the battery cell structure, simplify the battery cell structure and manufacturing process, and improve the battery cell production efficiency.

[0048] In some embodiments, the battery cell has four sides, with tabs on two opposite sides. The width of the heat-sealing area 21 on the side with tabs and the width of the heat-sealing area 21 on the side without tabs can be the same or different.

[0049] Optionally, the positive electrode tab 11 and the negative electrode tab 12 are welded to the electrode group 1.

[0050] According to an embodiment of the present invention, another aspect provides a battery pack including the aforementioned battery cell.

[0051] In this battery pack structure, the cells have a non-heat-sealed area 22 outside the heat-sealed area 21 on the side where the tabs are located. The width W2 of the non-heat-sealed area 22 satisfies 1mm ≤ W2 < W1. This setting allows the non-heat-sealed area 22 to have sufficient width to prevent excess glue from leaking out from the tab side, thus improving the appearance of the encapsulated cells. At the same time, the excess glue is shielded inside the non-heat-sealed area 22, which can effectively prevent the excess glue from damaging the encapsulation film 2 during micro-drop tests, thus improving the safety performance of the battery pack. In addition, W2 < W1, this setting can prevent the non-heat-sealed area 22 from being too wide, which would waste materials, and can also prevent the encapsulation film 2 from taking up too much space, thereby improving the volumetric energy density of the battery pack.

[0052] 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: A pole group, wherein the pole group is provided with pole tabs on its side; An encapsulation film is used to cover the electrode assembly. The encapsulation film outside the circumferential outer edge of the electrode assembly is heat-sealed to form a heat-sealed area. A non-heat-sealed area is provided outside the heat-sealed area on the side where the electrode tab is located. The width of the heat-sealed area is W1, and the width of the non-heat-sealed area is W2, where 1mm ≤ W2 < W1.

2. The battery cell according to claim 1, characterized in that, It also includes an insulating element disposed between the tab and the encapsulation film; along the width direction of the heat-sealing area, the outer edge of the insulating element is located outside the non-heat-sealing area, and the inner edge of the insulating element is located inside the heat-sealing area.

3. The battery cell according to claim 2, characterized in that, The width between the outer edge of the insulating element and the outer edge of the non-heat-sealed area is W3, where 2mm ≤ W3 ≤ 8mm.

4. The battery cell according to claim 3, characterized in that, The width between the inner edge of the insulating element and the inner edge of the heat-sealing area is W4, where 2mm ≤ W4 ≤ 8mm.

5. The battery cell according to any one of claims 2 to 4, characterized in that, The width of the insulating element is W, and 50% ≤ W1 / W ≤ 80%.

6. The battery cell according to claim 5, characterized in that, 60% ≤ W1 / W ≤ 80%.

7. The battery cell according to any one of claims 2 to 4, characterized in that, The two ends of the insulating component along its length are located outside the tab. The length of the insulating component is L, and the length of the tab is L1, where 3mm ≤ L - L1 ≤ 8mm.

8. The battery cell according to claim 7, characterized in that, 1.1≤L / L1≤1.

5.

9. The battery cell according to any one of claims 1 to 4, characterized in that, The electrode tabs include a positive electrode tab and a negative electrode tab, which are located on opposite sides of the electrode group.

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

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