Battery cell and battery pack

Abstract

The application relates to the technical field of batteries, and discloses a battery cell and a battery pack. The battery cell comprises a pole group and a packaging film. The length between the main folding edge section and the secondary folding edge section of the battery cell can effectively guarantee the length of the secondary folding edge section, avoid the length of the secondary folding edge section being too short to cause the secondary folding edge section to easily lift after being bent, guarantee the length of the secondary folding edge section after being bent to be sufficient to the main folding edge section, effectively guarantee the secondary folding edge section to be attached to the main folding edge section, guarantee the folding edge effect, stabilize the folding edge structure, improve the packaging strength of the packaging film, and sequentially attach the folding edge sections of the folding edge structure after being folded, prolong the distance between the end of the sealing edge area and the internal pole group, simultaneously make the path of external water vapor entering the internal packaging film more winding and circuitous, effectively prevent external water vapor from entering the internal packaging film, and effectively improve the packaging effect of the packaging film.

Description

Technical Field

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

[0002] A pouch cell battery mainly consists of electrode groups and a sealing film. The sealing film includes a main body and an edge sealing area. The main body wraps around the electrode groups, and then the sealing film is hot-pressed onto the outside of the electrode groups to seal them within the sealing film. The hot-pressed sealing film forms the edge sealing area, which extends outward roughly parallel to the large surface of the cell. To reduce the space occupied by the edge sealing area in the width direction of the cell, the edge sealing area is folded towards the side of the cell to form a folded edge structure. Existing folded edge structures are prone to warping and deformation between segments after folding, resulting in ineffective adhesion between the bent segments, leading to poor folding and affecting the sealing strength at the folded edge of the sealing film. Summary of the Invention

[0003] In view of this, the present invention provides a battery cell and a battery pack to solve the problem that the segments of the folded edge structure of the battery cell in the prior art cannot be effectively bonded, which affects the encapsulation strength at the folded edge structure of the encapsulation film.

[0004] In a first aspect, the present invention provides a battery cell, comprising:

[0005] pole group;

[0006] An encapsulation film includes an encapsulation body and a sealing area. The encapsulation body covers the electrode assembly, and the sealing area is located outside the electrode assembly. The sealing area includes an extension and a folded edge structure. The extension extends outward from the electrode assembly, and the folded edge structure includes a main folded edge segment and at least two secondary folded edge segments. One end of the main folded edge segment is connected to the end of the extension segment away from the electrode assembly, and the other end is connected to the secondary folded edge segments. The main folded edge segment is bent towards one side of the electrode assembly in the thickness direction, and the secondary folded edge segments are bent towards the inner and / or outer side of the main folded edge segment. The folded edge segments of the folded edge structure are sequentially bonded together. The length of the main folded edge segment is L1, and the total length of the secondary folded edge segments is L.

[0007] Beneficial effects: In this cell structure, the length between the main folded section and the secondary folded section meets the requirements. This design effectively ensures the length of the secondary folded edge segment, preventing it from being too short and prone to warping after bending. It also ensures sufficient adhesion length between the secondary and main folded edge segments after bending, allowing the secondary folded edge segment to adhere effectively to the main folded edge segment, guaranteeing the folding effect and ensuring a stable folding structure, thus improving the encapsulation strength of the encapsulation film. Since the sealing area contains two layers of encapsulation film, which are heat-pressed to form the encapsulation area, moisture may enter between the two layers at the end of the encapsulation area. After folding, the various folded edges of the folding structure adhere sequentially, extending the distance between the end of the sealing area and the internal electrode assembly. Simultaneously, it makes the path for external moisture to enter the encapsulation film more tortuous and circuitous, effectively preventing external moisture from entering the encapsulation film and significantly improving the encapsulation effect.

[0008] In one optional embodiment, the secondary folded edge segment bends inward toward the main folded edge segment. The secondary folded edge segment includes a first folded edge segment, a second folded edge segment, and a third folded edge segment connected in sequence. The first folded edge segment is spaced apart from the main folded edge segment. One end of the first folded edge segment is connected to the main folded edge segment, and the other end is bent toward the extension. The second folded edge segment bends away from the extension and is attached to the outer wall surface of the first folded edge segment. The third folded edge segment bends toward the extension. The second folded edge segment and the third folded edge segment are located between the main folded edge segment and the first folded edge segment. The inner and outer wall surfaces of the third folded edge segment are respectively attached to the outer wall surface of the second folded edge segment and the inner wall surface of the main folded edge segment.

[0009] Beneficial effects: The folded edge structure forms four layers of folds, and each fold is sequentially bonded together, improving the overall stability and strength of the folded edge structure. At the same time, each secondary fold segment bends inward toward the main fold segment, which can reduce the space occupied by the secondary fold segments in the width direction of the cell and improve the compactness of the cell in the width direction.

[0010] In one optional implementation, the length of the first folded edge segment is L2. The end of the third folded edge segment is spaced apart from the extension to form an interval. The ends of the first folded edge segment and the second folded edge segment facing the extension are bent toward the main folded edge and located within the interval.

[0011] Beneficial effects: The cut edge is located at the end of the third folded edge segment, and the length of the first folded edge segment is greater than the length of the main folded edge segment. This allows the ends of the first and second folded edge segments facing the extension to bend towards the main folded edge and remain within the interval, blocking the cut edge inside the ends of the first and second folded edge segments. This effectively prevents the cut edge from contacting the extension and damaging it, thus ensuring the sealing effect of the encapsulation film. Simultaneously, the bending area between the first and second folded edge segments is located within the interval, improving the overall compactness of the folded structure and effectively enhancing its overall strength, thereby increasing the sealing strength of the encapsulation film.

[0012] In one optional implementation, the length of the first folded edge segment is L2.

[0013] Beneficial effects: This design ensures that the first folded edge segment has sufficient length to facilitate upward bending of the double-layer encapsulation area, while also guaranteeing the adhesion length between each folded edge segment after bending, thus ensuring the stability of the folded structure. Meanwhile... This arrangement keeps the ends of the first and second folded sections separate from the extension, preventing the encapsulation films from coming into contact with each other and causing wear.

[0014] In one optional embodiment, the distance between the end of the third folded edge segment facing the extension and the extension is D, where D ≥ 1 mm.

[0015] Beneficial effects: This setting can separate the cut edge at the end of the third folded edge from the extension, avoiding the cut edge from scratching the extension, ensuring the sealing effect of the encapsulation film, and improving the safety performance of the battery cell.

[0016] In one optional implementation, the length of the third folded segment is L3.

[0017] Beneficial effect: The length L3 of the third folded segment satisfies This design ensures the length of the third folded edge segment, guaranteeing the fit between the third folded edge segment and adjacent folded edge segments after folding, thus preventing the folded edge structure from warping. Simultaneously, This further ensures that the cut edge of the third folded section is separated from the extension, preventing the cut edge from damaging the extension.

[0018] In one alternative implementation, L3 ≤ L2.

[0019] Beneficial effect: This setting can prevent the third folded edge segment from extending beyond the ends of the first and second folded edge segments, and avoid damage to the extension portion by the cutting edge at the end of the third folded edge segment.

[0020] In one optional embodiment, the included angle between the main folded edge segment and the extension is θ, where 60°≤θ≤120°.

[0021] In one optional embodiment, the secondary folded edge segment includes a first folded edge segment, a second folded edge segment, and a third folded edge segment connected in sequence. The first folded edge segment is bent toward the extension and adhered to the inner wall surface of the main folded edge segment. The second folded edge segment is bent away from the extension and adhered to the inner wall surface of the first folded edge segment. The third folded edge segment is bent toward the extension and adhered to the outer wall surface of the main folded edge segment.

[0022] Secondly, the present invention also provides a battery pack comprising the battery cell described in any of the above descriptions. The battery pack, comprising the battery cell, has the same technical effects as the battery cell, and will not be elaborated further here. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a side view of a battery cell according to an embodiment of the present invention;

[0025] Figure 2 for Figure 1 A magnified view of part A in the diagram;

[0026] Figure 3 for Figure 1 A magnified view of part A in the diagram;

[0027] Figure 4 This is a schematic diagram of a folded edge structure in a battery cell according to an embodiment of the present invention;

[0028] Figure 5 This is a side view of another type of battery cell according to an embodiment of the present invention;

[0029] Figure 6 for Figure 5 Enlarged view of part B in the middle;

[0030] Figure 7 This is a side view of another type of battery cell according to an embodiment of the present invention.

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

[0032] 1. Encapsulation film; 11. Encapsulation body; 12. Sealing area; 121. Extension; 122. Folding structure; 1221. Main folding section; 1222. Secondary folding section; 12221. First folding section; 12222. Second folding section; 12223. Third folding section. Detailed Implementation

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

[0034] like Figure 1 , Figure 2 , Figure 3 and Figure 5 As shown, the x-direction is called the width direction of the battery cell, the z-direction is called the thickness direction of the battery cell, the upper part of the z-direction is called the upper part of the battery cell, the lower part of the z-direction is called the lower part of the battery cell, the large surface of the battery cell facing upward is its top surface, and the large surface of the battery cell facing downward is its bottom surface.

[0035] The following is combined Figures 1 to 7 The following describes embodiments of the present invention.

[0036] According to an embodiment of the present invention, in one aspect, a battery cell is provided, including an electrode assembly and an encapsulation film 1.

[0037] The encapsulation film 1 includes an encapsulation body 11 and a sealing area 12. The encapsulation body 11 covers the electrode assembly, and the sealing area 12 is located outside the electrode assembly. The sealing area 12 includes an extension 121 and a folded edge structure 122. The extension 121 extends outward toward the electrode assembly. The folded edge structure 122 includes a main folded edge segment 1221 and at least two secondary folded edge segments 1222. One end of the main folded edge segment 1221 is connected to the end of the extension 121 away from the electrode assembly, and the other end is connected to the secondary folded edge segments 1222. The main folded edge segment 1221 is bent toward the side of the electrode assembly in the thickness direction, and the secondary folded edge segments 1222 are bent toward the inner and / or outer side of the main folded edge segment 1221. The folded edge segments of the folded edge structure 122 are sequentially bonded together. The length of the main folded edge segment 1221 is L1, and the total length of the secondary folded edge segments 1222 is L.

[0038] In this battery cell structure, the length between the main folded edge segment 1221 and the secondary folded edge segment 1222 satisfies This effectively ensures the length of the secondary folded edge segment 1222, preventing it from being too short and prone to warping after bending. It also ensures sufficient bonding length between the secondary folded edge segment 1222 and the main folded edge segment 1221 after bending, allowing the secondary folded edge segment 1222 to effectively adhere to the main folded edge segment 1221, thus guaranteeing the folding effect. The folded edge structure 122 is stable and improves the encapsulation strength of the encapsulation film 1. Since the sealing area 12 contains two layers of encapsulation film 1, which are heat-pressed to form the encapsulation area, moisture may enter between the two layers of encapsulation film 1 at the end of the encapsulation area. After folding, each folded edge segment of the folded edge structure 122 is bonded together sequentially, extending the distance between the end of the sealing area 12 and the internal electrode assembly. At the same time, it makes the path for external moisture to enter the encapsulation film 1 more tortuous and circuitous, effectively preventing external moisture from entering the encapsulation film 1 and effectively improving the encapsulation effect of the encapsulation film 1.

[0039] like Figures 1 to 4 As shown, the secondary folded edge segment 1222 bends inward toward the main folded edge segment 1221. The secondary folded edge segment 1222 includes a first folded edge segment 12221, a second folded edge segment 12222, and a third folded edge segment 12223 connected in sequence. The first folded edge segment 12221 is spaced apart from the main folded edge segment 1221. One end of the first folded edge segment 12221 is connected to the main folded edge segment 1221, and the other end is bent toward the extension. The second folded edge segment 12222 bends away from the extension. The extension is bent, and the second folded edge segment 12222 is attached to the outer wall surface of the first folded edge segment 12221; the third folded edge segment 12223 is bent towards the extension. The second folded edge segment 12222 and the third folded edge segment 12223 are located between the main folded edge segment 1221 and the first folded edge segment 12221. The inner and outer walls of the third folded edge segment 12223 are respectively attached to the outer wall surface of the second folded edge segment 12222 and the inner wall surface of the main folded edge segment 1221. The folded edge structure 122 forms four layers of folds, and each fold is attached sequentially, which improves the overall stability and strength of the folded edge structure 122. At the same time, each secondary folded edge segment 1222 is bent towards the inside of the main folded edge segment 1221, which can reduce the space occupied by the secondary folded edge segments 1222 in the width direction of the cell and improve the compactness in the width direction of the cell.

[0040] In some embodiments, such as Figures 1 to 3 As shown, the length L1 of the main folded edge segment 1221 is greater than the total length L of the secondary folded edge segment 1222. This arrangement allows the end of the secondary folded edge segment 1222 facing the extension 121 to be spaced apart from the extension 121, preventing them from contacting and wearing each other. For example, in some embodiments, This arrangement ensures that the end of the secondary folded edge segment 1222 facing the extension 121 is sufficiently spaced from the extension 121, thus avoiding contact wear.

[0041] In other embodiments, such as Figure 4As shown, the length L1 of the main folded edge segment 1221 is less than the total length L of the secondary folded edge segment 1222. At this time, the length of the third folded edge segment 12223 is less than the length of the main folded edge segment 1221, so as to form an accommodating space between the third folded edge segment 12223 and the extension 121. The portion of the secondary folded edge segment 1222 that exceeds the length of the main folded edge segment 1221 is bent toward the accommodating space. The side of the secondary folded edge segment 1222 facing the extension 121 abuts against the extension 121, and the end of the secondary folded edge segment 1222 facing the main folded edge segment 1221 abuts against the inner wall surface of the main folded edge segment 1221, thereby forming a compact and stable folded edge structure 122, which can prevent the folded edge structure 122 from collapsing and can improve the encapsulation strength of the encapsulation film 1.

[0042] In some embodiments, such as Figure 4 As shown, the length of the first folded segment 12221 is L2. The end of the third folded edge segment 12223 is spaced apart from the extension portion 121 to form an interval. The ends of the first folded edge segment 12221 and the second folded edge segment 12222 facing the extension portion 121 are bent towards the main folded edge and located within the interval. Since the outer edge of the sealing area 12 is a cut edge with a sharp structure, the cut edge can easily damage the encapsulation film 1 after contacting it. In this battery cell structure, the cut edge is located at the end of the third folded edge segment 12223, and the length of the first folded edge segment 12221 is greater than the length of the main folded edge segment 1221. This allows the ends of the first folded edge segment 12221 and the second folded edge segment 12222 facing the extension portion 121 to be bent towards the main folded edge and located within the interval, blocking the cut edge inside the ends of the first folded edge segment 12221 and the second folded edge segment 12222. This effectively prevents the cut edge from contacting the extension portion 121 and damaging it, thus effectively ensuring the encapsulation effect of the encapsulation film 1. Meanwhile, the bending area between the first folded edge segment 12221 and the second folded edge segment 12222 is located within the interval, which improves the overall compactness of the folded edge structure 122 and effectively improves the overall strength of the folded edge structure 122, thereby improving the encapsulation strength of the encapsulation film 1.

[0043] In some embodiments, such as Figure 2 As shown, the length of the first folded segment 12221 is L2. When bending the edge structure 122, the sealing area 12 extends roughly horizontally with the large surface of the battery cell. First, the sealing area 12 is bent upwards to form two layers of double-layer encapsulation area that fit together. Then, the middle area of ​​the double-layer encapsulation area is bent upwards to form a four-layer structure. Finally, the single-layer extension 121 on the inner side of the four-layer structure is bent vertically upwards to form the four-layer edge structure 122. Figure 2The x-direction is called the thickness direction of the folded edge structure 122. If the length of the first folded edge segment 12221 is too short, it is inconvenient to bend the double-layer encapsulation area upward from the middle. Furthermore, after bending, the first folded edge segment 12221 and the second bending segment are prone to deformation and warping. If the length of the first folded edge segment 12221 is too short, along the thickness direction of the cell, the folded edge structure 122 in the areas with the first folded edge segment 12221, the second folded edge segment 12222, and the third folded edge segment 12223 will be thicker, while only the folded edge structure 122 at the main folded edge segment 1221 will be thin. This results in the folded edge structure 122 being thicker at the top and thinner at the bottom, making the first folded edge segment 12221, the second folded edge segment 12222, and the third folded edge segment 12223 prone to collapsing downwards, affecting the flatness of the side surface of the folded edge structure 122. To avoid this problem, the length of the first folded edge segment 12221 in this application is L2, which satisfies... This design ensures that the first folded edge segment 12221 has sufficient length to facilitate upward bending of the double-layer encapsulation area, while also guaranteeing the bonding length between each folded edge segment after bending, thus ensuring the stability of the folded edge structure 122. Meanwhile... This arrangement allows the ends of the first folded edge segment 12221 and the second folded edge segment 12222 to be spaced apart from the extension portion 121, preventing the encapsulation films 1 from coming into contact with each other and causing wear.

[0044] In some embodiments, such as Figure 2 As shown, the distance between the end of the third folded edge segment 12223 facing the extension 121 and the extension 121 is D, where D≥1mm. This setting can separate the cut edge at the end of the third folded edge segment 12223 from the extension 121, avoiding the cut edge from scratching the extension 121, ensuring the encapsulation effect of the encapsulation film 1, and improving the safety performance of the battery cell.

[0045] In some embodiments, such as Figure 2 As shown, the length of the third folded segment 12223 is L3. If the length of the third folded edge segment 12223 is too short, after bending, its length in contact with the main folded edge segment 1221 and the second bending segment will be insufficient, causing the folded edge structure 122 to easily lift up, affecting the sealing strength of the sealing area 12 of the encapsulation film 1. To avoid this problem, the length L3 of the third folded edge segment 12223 in this structure satisfies... This design ensures the length of the third folded edge segment 12223, guaranteeing the fit length between the third folded edge segment 12223 and adjacent folded edge segments after folding, thus preventing the folded edge structure 122 from warping. Simultaneously, This can further ensure that the cut edge of the third folded section 12223 is separated from the extension 121, preventing the cut edge from damaging the extension 121.

[0046] In some embodiments, such as Figure 2As shown, L3≤L2, that is, the length of the third folded edge segment 12223 is less than or equal to the length of the first folded edge segment 12221. This setting can prevent the third folded edge segment 12223 from exceeding the ends of the first folded edge segment 12221 and the second folded edge segment 12222, and avoid damage to the extension 121 by the cut edge at the end of the third folded edge segment 12223.

[0047] In some embodiments, the included angle between the main folded edge segment 1221 and the extension 121 is θ, where 60°≤θ≤120°. The included angle between the main folded edge segment 1221 and the extension 121 is moderate, which can prevent the folded edge structure 122 from tilting too much inward or outward along the width direction of the battery cell and thus occupying too much space.

[0048] For example, in some embodiments, the main folded edge segment 1221 is arranged perpendicularly to the extension 121. This arrangement can further reduce the space occupied by the folded edge structure 122 in the width direction of the cell, improve the compactness of the overall cell structure, and increase the volumetric energy density of the cell.

[0049] like Figure 2 As shown, in some embodiments, the sealing area 12 is located on one side in the thickness direction of the battery cell, and the folded edge structure 122 is bent upwards. The total thickness of the battery cell is H, and the length of the folded edge structure 122 is less than H. This arrangement can prevent the top of the folded edge structure 122 from extending beyond the top surface of the battery cell, thereby improving the space utilization and volumetric energy density of the battery cell.

[0050] In other embodiments, such as Figure 7 As shown, the sealing area 12 is located in the middle region in the thickness direction of the electrode group, and the folded edge structure 122 is bent toward the top or bottom of the cell.

[0051] like Figure 5 and Figure 6 As shown, the secondary folded edge segment 1222 includes a first folded edge segment 12221, a second folded edge segment 12222, and a third folded edge segment 12223 connected in sequence. The first folded edge segment 12221 is bent toward the extension and adhered to the inner wall surface of the main folded edge segment 1221. The second folded edge segment 12222 is bent away from the extension and adhered to the inner wall surface of the first folded edge segment. The third folded edge segment is bent toward the extension and adhered to the outer wall surface of the main folded edge segment 1221. That is, the first folded edge segment 12221 and the second folded edge segment 12222 are located inside the main folded edge segment 1221, and the third folded edge segment 12223 is located outside the main folded edge segment 1221. This arrangement keeps the third folded edge segment 12223 away from the side of the encapsulation body 11, which can effectively prevent the cutting edge from damaging the side of the encapsulation body 11 when the third folded edge segment 12223 deforms and warps, thereby ensuring the integrity of the encapsulation film 1 and ensuring the sealing and protection effect of the encapsulation film 1.

[0052] According to an embodiment of the present invention, another aspect provides a battery pack including the aforementioned battery cells.

[0053] In this battery cell structure, the length between the main folded edge segment 1221 and the secondary folded edge segment 1222 satisfies This effectively ensures the length of the secondary folded edge segment 1222, preventing it from being too short and prone to warping after bending. It ensures the secondary folded edge segment 1222 adheres effectively to the main folded edge segment 1221 after bending, guaranteeing the folding effect. The folded edge structure 122 is stable, improving the encapsulation strength of the encapsulation film 1, thus enhancing the overall strength of the battery cell and battery pack. After folding, each folded edge segment of the folded edge structure 122 adheres sequentially, extending the distance between the end of the sealing area 12 and the internal electrode assembly. Simultaneously, it makes the path for external moisture to enter the encapsulation film 1 more tortuous and circuitous, effectively preventing external moisture from entering the encapsulation film 1 and improving the safety performance of the battery cell and battery pack.

[0054] Although embodiments of the 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 invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An electric cell, characterized by, Comprise: Pole group; The encapsulation film comprises an encapsulation body and an edge sealing area, the encapsulation body is wrapped outside the pole group, the edge sealing area is located outside the pole group, the edge sealing area comprises an extension part and a folded edge structure, the extension part extends towards the outside of the pole group, the folded edge structure comprises a main folded edge segment and at least two secondary folded edge segments, one end of the main folded edge segment is connected to the end of the extension part away from the pole group, and the other end is connected to the secondary folded edge segment; the main folded edge segment is bent towards one side in the thickness direction of the pole group, the secondary folded edge segment is bent towards the inner side and / or the outer side of the main folded edge segment, and the folded edge structure is sequentially attached between each folded edge segment; the length of the main folded edge segment is L1, and the total length of the secondary folded edge segments is L, ; an angle between the main fold segment and the extension is θ, ; The secondary folding section comprises a first folding section, a second folding section and a third folding section connected in sequence, the first folding section is bent towards the extension and is attached to the inner wall surface of the main folding section, the second folding section is bent away from the extension and is attached to the inner wall surface of the first folding section; the third folding section is bent towards the extension and is attached to the outer wall surface of the main folding section.

2. The electric cell of claim 1, wherein, the length of the first folded edge section is L2, .

3. The electric cell of claim 2, wherein, The distance between the end of the third folding section towards the extension and the extension is D, D≥1mm.

4. The electric cell of any one of claims 1-3, wherein, the length of the third fold segment is L3, .

5. The electric cell of claim 4, wherein, L3≤L2.

6. A battery pack, characterized by, The electric cell of any one of claims 1 to 5.

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