Battery cell and battery pack

Abstract

The invention relates to the technical field of batteries, and discloses a battery cell and a battery pack. The battery cell comprises a pole group; the packaging film comprises a main body area and an edge sealing structure, the main body area corresponds to the pole group, the edge sealing structure is connected to at least one side edge of the main body area, the edge sealing structure comprises a first folding edge, a second folding edge and a third folding edge which are formed by bending, and the second folding edge is located on the side, away from the main body area, of the first folding edge; the first edgefold and the second edgefold are oppositely arranged, a spacing groove is formed between the first edgefold and the second edgefold, the first end of the third edgefold is connected with the second edgefold, the second end of the third edgefold extends into the spacing groove, and the size of the third edgefold extending into the spacing groove is L in the groove depth direction of the spacing groove; the body thickness of the edge sealing structure is h, and L and h meet the relational expression that 6 < = L / h < = 100. The whole edge sealing structure is bent and folded, the overall size and occupied space of the battery cell are reduced, stacking and fixing of the battery cell are facilitated, it can be guaranteed that the third folded edge is stably inserted into the interval groove, and design excess is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to an electric core and a battery pack. Background Art

[0002] The electric core has advantages such as high specific energy, small volume, and light weight, and has a large application market. The electric core mainly consists of a tab, a pole group, and a packaging film. The packaging film encapsulates the pole group and the tab, and seals the four peripheral edges of the packaging film by hot pressing to form a seal at the edge of the packaging film. For the side of the electric core where no tab is provided, the part of the packaging film that extends beyond the pole group forms a sealing edge. In the prior art, the sealing edge is usually not further managed. The free-state sealing edge has a long dimension, which will affect the overall dimension of the electric core, resulting in inconvenient stacking of the electric cores in the whole pack, excessive space occupied by the electric cores in the whole pack, and inconvenient fixing of the electric cores, affecting the stability of the electric cores in the entire battery pack. Summary of the Invention

[0003] In view of this, the present invention provides an electric core and a battery pack to solve the problem that the free-state sealing edge causes excessive space occupation of the electric cores in the whole pack and affects battery stacking.

[0004] In a first aspect, the present invention provides an electric core, including: a pole group; a packaging film, including a main body area and a sealing edge structure. The main body area corresponds to the pole group. The sealing edge structure is connected to at least one side of the main body area. The sealing edge structure includes a first folded edge, a second folded edge, and a third folded edge formed by bending. The second folded edge is located on the side of the first folded edge away from the main body area. The first folded edge and the second folded edge are oppositely arranged and form a spacer groove therebetween. The first end of the third folded edge is connected to the second folded edge and the second end extends into the spacer groove. Along the depth direction of the spacer groove, the dimension of the third folded edge extending into the spacer groove is L; the body thickness of the sealing edge structure is h, wherein, L and h satisfy the relationship: 6≤L / h≤100.

[0005] Beneficial effects: By setting the edge-sealing structure of the encapsulation film to include a first folded edge, a second folded edge, and a third folded edge connected in sequence, the overall edge-sealing structure can be bent and folded inwards, reducing the size of the edge-sealing structure extending outwards from the main body area, thereby reducing the overall size of the battery cell, and further reducing the occupied space of a single battery cell in the battery pack, improving the space utilization rate inside the battery pack, facilitating the stacking and fixing of the battery cells. At the same time, by limiting the ratio L / h between the size L of the third folded edge extending into the spacer groove and the body thickness h of the edge-sealing structure 102 to be within the range of 6 to 100, a reasonable limitation is imposed on the folded-edge parameters, which can not only ensure that the third folded edge stably inserts into the spacer groove, preventing the third folded edge from having too large a warping angle and scratching the first folded edge, and preventing the third folded edge from disengaging from the spacer groove and piercing the outer surface of the main body area, ensuring the reliability and effectiveness of the folded edge, but also avoiding over-design, thus saving space and materials, and preventing the size of the third folded edge extending into the spacer groove from being too large and interfering with the bottom of the spacer groove, thereby ensuring the smooth formation of the edge-sealing structure.

[0006] In an alternative embodiment, the range of values of the body thickness h of the edge-sealing structure is: 0.2 mm ≤ h ≤ 6 mm; and / or, along the depth direction of the spacer groove, the range of values of the size L of the third folded edge extending into the spacer groove is: 1.2 mm ≤ L ≤ 50 mm.

[0007] Beneficial effects: By setting the body thickness h of the edge-sealing structure to be within the range of 0.2 mm to 6 mm, it can not only ensure that the encapsulation film provides sufficient protection for the electrode group, but also ensure that each folded edge of the edge-sealing structure can be smoothly bent, and ensure that the bent third folded edge will not pierce the first folded edge due to too large a warping angle or disengage from the spacer groove and pierce the outer surface of the main body area, thereby ensuring the reliability of the edge-sealing structure and the safety of the battery cell;

[0008] By limiting the size L of the third folded edge extending into the spacer groove to be within the range of 1.2 mm to 50 mm, it can not only avoid the difficulty of bending due to the third folded edge being too short, reduce the difficulty of bending and forming, and ensure that the third folded edge fits with the first folded edge, preventing the third folded edge from scratching the first folded edge due to too large a warping angle, thereby ensuring the sealing performance of the encapsulation film, but also avoid wasting materials due to the third folded edge being too long, and avoid interference with the first transition section, ensuring the smooth formation of the second folded edge relative to the first folded edge during the bending process, thereby ensuring the reliability of the edge-sealing structure.

[0009] In an alternative embodiment, the first folded edge and the second folded edge are connected by a first transition section, and the second end of the third folded edge is spaced from the first transition section along the depth direction of the spacer groove.

[0010] Beneficial effects: By arranging the third folded edge and the first transition section at intervals in the groove depth direction, interference between the third folded edge and the first transition section can be avoided, thereby preventing the third folded edge from affecting the bending and forming of the second folded edge relative to the first folded edge, ensuring the smooth bending of each folded edge of the edge-sealing structure, and ensuring the reliability of the edge-sealing structure.

[0011] In an optional embodiment, along the groove depth direction of the spacing groove, the maximum distance between the second end of the third folded edge and the side surface of the first transition section facing the third folded edge is L1, where the relationship between L1 and h satisfies: 3 ≤ L1 / h ≤ 100.

[0012] Beneficial effects: By setting the ratio L1 / h of the distance L1 between the second end of the third folded edge and the first transition section to the body thickness h of the edge-sealing structure to be between 6 and 100, it can not only prevent the second folded edge from warping relative to the first folded edge, ensure the smooth bending and forming when the second folded edge and the first folded edge are folded against each other, reduce the forming difficulty, but also avoid over-design, thereby saving space and materials.

[0013] In an optional embodiment, the extending directions of the first folded edge, the second folded edge, and the third folded edge are all parallel to the thickness direction of the battery cell.

[0014] Beneficial effects: If the first folded edge, the second folded edge, and the third folded edge are parallel to each other, it can prevent the third folded edge from warping relative to the second folded edge and scratching the first folded edge, and the extending directions of each folded edge are all parallel to the thickness direction of the battery cell, so that each folded edge is parallel to the side surfaces on both sides in the width direction of the main body area, which can prevent the folded edge structure formed by each folded edge from damaging the main body area, with high safety and good stability.

[0015] In an optional embodiment, the edge-sealing structure further includes: a connecting section, which is connected between the main body area and the first folded edge, the connecting section is arranged at an angle with the first folded edge, and the first folded edge is spaced from the main body area.

[0016] Beneficial effects: By setting that the edge-sealing structure further includes a connecting section connected between the main body area and the first folded edge, the first folded edge is spaced from the main body area, ensuring that a certain length is left for the lead-out end of the encapsulation film located outside the electrode group, preventing the bending structure from being bent and pulled to affect the fitting degree between the electrode group and the encapsulation film, and keeping the bending structure away from the weak area of the punching pit, thereby improving the safety performance of the battery cell.

[0017] In an optional embodiment, the connecting section is perpendicular to the first folded edge, and the horizontal distance between the first folded edge and the main body area is C, where 1 mm ≤ C ≤ 30 mm.

[0018] Beneficial effects: It can avoid the first folding edge being too close to the main body area, thus ensuring a certain length for the leading end of the edge-sealing structure located outside the electrode group, preventing the edge-sealing structure from being bent and pulled to affect the electrode group, and making the bending structure away from the weak area of the punching pit, improving the safety performance of the battery cell. At the same time, it can avoid the first folding edge being too far from the main body area, resulting in an excessive size of the edge-sealing structure in the width direction, thereby achieving the purpose of reducing the overall size of the battery cell, improving the space utilization rate inside the battery pack, and facilitating the stacking and fixing of the battery cells.

[0019] In an optional implementation manner, along the thickness direction of the battery cell, the main body area has a first surface and a second surface arranged oppositely, the distance from the first transition section to the first surface is less than the distance from the first transition section to the second surface, and the shortest distance between the first transition section and the first surface is h1, where h1 ≥ 0.1 mm.

[0020] Beneficial effects: By setting the first folding edge on the side of the connecting section close to the first surface, the first transition section connected to the end of the first folding edge far from the connecting section is the part of the edge-sealing structure closest to the first surface. At the same time, by defining that the shortest distance h1 between the first transition section and the first surface is greater than or equal to 0.1 mm, it is ensured that there is a certain interval between the end of the edge-sealing structure close to the first surface and the first surface along the thickness direction of the battery cell, ensuring that the edge-sealing structure does not protrude from the main body area along the thickness direction of the battery cell, avoiding affecting the stacking of the battery cell in the whole package, and improving the space utilization rate inside the battery pack.

[0021] In an optional implementation manner, along the thickness direction of the battery cell, the size of the second folding edge is greater than the size of the first folding edge, the second folding edge and the third folding edge are connected by a second transition section, and the distance between the second transition section and the second surface along the thickness direction of the battery cell is h2, where h2 ≥ 0.1 mm.

[0022] Beneficial effects: By setting that along the thickness direction of the battery cell, the size of the second folding edge is greater than the size of the first folding edge, the upper end of the second folding edge is higher than the upper end of the first folding edge. Then the second transition section connected to the upper end of the second folding edge is the part of the edge-sealing structure closest to the second surface along the thickness direction of the battery cell. By defining that the distance h2 between the second transition section and the second surface along the thickness direction of the battery cell is greater than or equal to 0.1 mm, it is ensured that there is a certain interval between the end of the edge-sealing structure close to the second surface and the second surface along the thickness direction of the battery cell, ensuring that the edge-sealing structure does not protrude from the main body area along the thickness direction of the battery cell, avoiding affecting the stacking of the battery cell in the whole package, and improving the space utilization rate inside the battery pack.

[0023] Second aspect, the present invention further provides a battery pack, including: the above-mentioned battery cell. Since the battery pack includes the battery cell and has the same effects as the battery cell, details are not described herein again. Description of the Drawings

[0024] 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 use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic structural diagram of a traditional battery cell;

[0026] Figure 2 It is a top view of a battery cell according to an embodiment of the present invention;

[0027] Figure 3 It is Figure 2 a side view of the battery cell shown;

[0028] Figure 4 It is Figure 3 a partial enlarged schematic view of one side edge of the battery cell shown close to the width direction;

[0029] Figure 5 It is a schematic structural diagram when the warping angle of the third folded edge is too large.

[0030] Description of the reference numerals:

[0031] 1. Encapsulation film; 101. Main body area; 1011. First surface; 1012. Second surface; 102. Edge sealing structure; 111. First folded edge; 112. Second folded edge; 113. Third folded edge; 114. First transition section; 115. Connection section; 116. Second transition section; 117. Spacing groove; 2. Tab; 3. Seal; 4. Sealing member. Specific Embodiments

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0033] The traditional battery cell does not further manage the edge sealing structure 102, and the edge sealing structure is in a free state, or, as Figure 1As shown, by simply bending the edge-sealing structure 102 upward once, the edge-sealing structure 102 extends in the up-and-down direction and has a relatively large size. The upper end of the edge-sealing structure 102 will exceed the upper surface of the main body area 101 of the encapsulation film 1, seriously affecting the overall size of the battery cell, resulting in inconvenient stacking of battery cells in the whole package, excessive space occupied by the battery cells in the whole package, and inconvenient fixation of the battery cells.

[0034] Next, in conjunction with Figures 2 to 5 , embodiments of the present invention will be described.

[0035] According to an embodiment of the present invention, on the one hand, a battery cell is provided, as Figures 2 to 4 shown. The battery cell includes: a pole group and an encapsulation film 1. The encapsulation film 1 includes a main body area 101 and an edge-sealing structure 102. The main body area 101 corresponds to the pole group. The edge-sealing structure 102 is connected to at least one side of the main body area 101. The edge-sealing structure 102 includes a first folded edge 111, a second folded edge 112, and a third folded edge 113 formed by bending. The second folded edge 112 is located on the side of the first folded edge 111 away from the main body area 101. The first folded edge 111 and the second folded edge 112 are arranged opposite to each other and form a spacer groove 117 therebetween. The first end of the third folded edge 113 is connected to the second folded edge 112 and the second end extends into the spacer groove 117. Along the groove depth direction of the spacer groove 117, the size of the third folded edge 113 extending into the spacer groove 117 is L; the body thickness of the edge-sealing structure 102 is h, where the relationship between L and h satisfies the formula: 6 ≤ L / h ≤ 100.

[0036] It should be noted that the groove depth direction refers to the "up-and-down direction" indicated by the arrow in Figures 3 to 4 ; the body thickness of the edge-sealing structure 102 refers to the thickness of the edge-sealing of the encapsulation film 1 itself; further in conjunction with Figures 3 to 4 shown, the size of the connecting section 115 in the "up-and-down direction" indicated by the arrow in Figures 3 to 4 , and the sizes of the first folded edge 111, the second folded edge 112, and the third folded edge 113 in the "width direction" indicated by the arrow in Figures 3 to 4 are all the body thickness of the edge-sealing structure 102; the units of L and h are both mm.

[0037] When applying the battery cell of this embodiment, by setting the edge-sealing structure 102 of the encapsulation film 1 to include a first folded edge 111, a second folded edge 112, and a third folded edge 113 that are connected in sequence, the overall edge-sealing structure 102 can be bent and folded inwards, reducing the size of the edge-sealing structure 102 extending outwards from the main body area 101, thus reducing the overall size of the battery cell, and further reducing the occupied space of a single battery cell in the battery pack, improving the space utilization rate inside the battery pack, facilitating the stacking and fixing of the battery cells. At the same time, by restricting the ratio L / h of the size L of the third folded edge 113 extending into the spacer groove 117 to the body thickness h of the edge-sealing structure 102 to be between 6 and 100, the folded-edge parameters are reasonably limited. This can not only ensure that the third folded edge 113 stably inserts into the spacer groove 117, preventing the third folded edge 113 from having an excessive warping angle and scratching the first folded edge 111, and preventing the third folded edge 113 from disengaging from the spacer groove 117 and piercing the outer surface of the main body area 101, ensuring the reliability and effectiveness of the folded edge, but also avoid over-design, thus saving space and materials, and preventing the size of the third folded edge 113 extending into the spacer groove 117 from being too large and interfering with the bottom of the spacer groove 117, thereby ensuring the smooth formation of the edge-sealing structure 102.

[0038] It should be noted that when the body thickness h of the edge-sealing structure 102 is larger, the folded edge after bending is subject to a greater rebound force, making it difficult to bend the folded edge. The second end of the third folded edge 113 after bending is more likely to warp, easily scratching the first folded edge 111 and disengaging from the spacer groove 117, and then piercing the main body area 101. Therefore, it is necessary to appropriately increase the size L of the third folded edge 113 extending into the spacer groove 117 to prevent the third folded edge 113 from disengaging from the spacer groove 117. Thus, the ratio of L / h cannot be too small. If L / h is less than 6, the above problems will occur. If L / h is greater than 100, although the above problems do not exist, the size of the third folded edge 113 extending into the spacer groove 117 is too large, resulting in over-design, wasting space and materials, and there may be a situation where the third folded edge 113 is too long and interferes with the bottom of the spacer groove 117. Herein, the bottom of the spacer groove 117 refers to the first transition section 114 at the connection between the first folded edge 111 and the second folded edge 112.

[0039] In one embodiment, the bent edge-sealing structure 102 is bundled on the main body area 101 with tape, preventing the various folded edges of the edge-sealing structure 102 from spreading, increasing the stability of the overall structure, further reducing the occupied space of a single battery cell in the battery pack, and preventing the placement of other battery cells in the battery pack from being affected.

[0040] It should be noted that the battery cell is a soft-pack battery cell, and the battery cell further includes tab 2. The tab 2 is an external tab, including a positive tab and a negative tab. The encapsulation film 1 includes a first film body and a second film body that are oppositely arranged in the up-down direction and are buckled with each other. The electrode assembly is located between the first film body and the second film body. During the assembly of the battery cell, first, the electrode assembly is welded to the positive and negative external tabs through internal tabs, then the welded electrode assembly is placed into the punching pit on the first film body, and then the second film body is covered, and the four sides are edge-bonded and heat-sealed to form a seal 3, and both ends are led out through the tab 2. The sealing edge structure 102 of the encapsulation film 1 after heat-sealing extends in the horizontal direction, and then the sealing edge structure 102 is bent. It is bent in sequence from the side of the sealing edge structure 102 far from the main body area 101 to the side close to the main body area 101 to form a third folded edge 113, a second folded edge 112, and a first folded edge 111 in sequence. Among them, the horizontal direction refers to Figures 3 to 4 the direction on the plane of the "width direction" indicated by the arrow in Figures 3 to 4 , which is parallel to the large surface of the battery cell.

[0041] In one embodiment, at a position corresponding to the seal 3, a seal 4 is provided between the tab 2 and the encapsulation film 1. The seal 4 is preferably PP glue, which facilitates the heat-sealing of the tab 2 and the encapsulation film 1 and ensures the sealing performance after heat-sealing. Preferably, the encapsulation film 1 is an aluminum-plastic film; the first film body and the second film body have the same structure and are symmetrically arranged.

[0042] In one embodiment, as Figures 1 to 3 shown, the battery cell has tabs at both ends. Along the width direction of the battery cell, sealing edge structures 102 are connected to both sides of the main body area 101; it can be understood that as an alternative embodiment, the sealing edge structure can also be provided only on one side of the main body area 101.

[0043] In addition, in other embodiments, if the battery cell has a tab at one end (not shown in the figure), then the sealing edge structure 102 can be provided on the three side edges without tabs, which can further reduce the size of the battery cell.

[0044] In one embodiment, the value range of the body thickness h of the edge-sealing structure 102 is: 0.2 mm ≤ h ≤ 6 mm. If h is less than 0.2 mm, the body thickness of the edge-sealing structure 102 is too small. Correspondingly, the film body of the encapsulation film 1 is too thin to provide sufficient protection for the internal electrode group. If h is greater than 6 mm, the body thickness of the edge-sealing structure 102 is too large, making it difficult to bend the folded edge, not easy to bend and form, and the warping angle of the third folded edge 113 after bending is too large, which is likely to scratch the first folded edge 111 or break away from the spacer groove 117. Therefore, by setting the value of the body thickness h of the edge-sealing structure 102 within the range of 0.2 mm to 6 mm, it can not only ensure that the encapsulation film 1 can provide sufficient protection for the electrode group, but also ensure that each folded edge of the edge-sealing structure 102 can be bent smoothly, and ensure that the third folded edge 113 after bending will not pierce the first folded edge 111 due to an excessive warping angle or break away from the spacer groove 117 and pierce the outer surface of the main body area 101, thus ensuring the reliability of the edge-sealing structure 102 and the safety of the battery cell.

[0045] In one embodiment, along the depth direction of the spacer groove 117, the value range of the dimension L of the third folded edge 113 extending into the spacer groove 117 is: 1.2 mm ≤ L ≤ 50 mm. If L is less than 1.2 mm, the dimension of the third folded edge 113 extending into the spacer groove 117 is too short, making it difficult to bend the third folded edge 113. The third folded edge 113 is likely to warp under the action of the bending rebound force, forming a warping shape as shown in Figure 5 shown. When the warping angle α of the third folded edge 113 is too large, it will scratch the first folded edge 111 and damage the sealing performance of the encapsulation film 1, thus affecting the safety of the battery cell. If L is greater than 50 mm, the dimension of the third folded edge 113 extending into the spacer groove 117 is too large, wasting materials and may interfere with the first transition section 114, affecting the bending and forming of the second folded edge 112 relative to the first folded edge 111.

[0046] Therefore, by limiting the value of the dimension L of the third folded edge 113 extending into the spacer groove 117 within the range of 1.2 mm to 50 mm, it can not only avoid the difficulty in bending due to the too short third folded edge 113, reduce the bending and forming difficulty, and ensure the third folded edge 113 is in contact with the first folded edge 111, avoiding the third folded edge 113 scratching the first folded edge 111 due to an excessive warping angle, thus ensuring the sealing performance of the encapsulation film 1, but also avoid wasting materials due to the too long third folded edge 113 and avoid interference with the first transition section 114, ensuring the smooth forming of the second folded edge 112 relative to the first folded edge 111 during the bending process, thus ensuring the reliability of the edge-sealing structure 102.

[0047] In one embodiment, the first hemming edge 111 and the second hemming edge 112 are connected by a first transition section 114, and the second end of the third hemming edge 113 is spaced from the first transition section 114 in the groove depth direction of the spacing groove 117. Further in combination with Figure 4 As shown, the first hemming edge 111 extends from top to bottom, the second hemming edge 112 extends from the lower right to the upper right, and the first transition section 114 is arranged at the lower ends of the first hemming edge 111 and the second hemming edge 112, wherein, "top" refers to Figure 4 the direction of "top" indicated by the arrow in Figure 4 ; "bottom" refers to

[0048] the direction of "bottom" indicated by the arrow in

[0049] By arranging the third hemming edge 113 to be spaced from the first transition section 114 in the groove depth direction, interference between the third hemming edge 113 and the first transition section 114 can be avoided, so as to prevent the third hemming edge 113 from affecting the bending and forming of the second hemming edge 112 relative to the first hemming edge 111, thereby ensuring the smooth bending of each hemming edge of the edge sealing structure 102 and ensuring the reliability of the edge sealing structure 102. Figures 3 to 4 As shown, the first hemming edge 111, the second hemming edge 112 and the third hemming edge 113 all extend in a direction parallel to the thickness direction of the battery cell. That is, the first hemming edge 111, the second hemming edge 112 and the third hemming edge 113 all extend along

[0050] the "up and down direction" indicated by the arrow in Figures 3 to 4 . If the first hemming edge 111, the second hemming edge 112 and the third hemming edge 113 are parallel to each other, warping of the third hemming edge 113 relative to the second hemming edge 112 can be avoided so as not to scratch the first hemming edge 111, and the extending directions of all the hemming edges are parallel to the thickness direction of the battery cell, so that each hemming edge is parallel to the side surfaces on both sides of the main body area 101 in the width direction, and damage to the main body area 101 caused by the hemming edge structure formed by each hemming edge can be avoided, with high safety and good stability.

[0051] Preferably, along the width direction of the battery cell, the size of the spacing groove 117 is the same as the size of the third hemming edge 113, so that one side of the part of the third hemming edge 113 extending into the spacing groove 117 is in contact with the first hemming edge 111 and the other side is in contact with the second hemming edge 112. The state where the hemming edges are in contact with each other can increase the stability of the hemming edge structure and can further reduce the occupied space in the width direction of the battery cell. Wherein, the width direction refers to Figures 3 to 4 the "width direction" indicated by the arrow in

[0051] In one embodiment, along the groove depth direction of the spacing groove 117, the maximum distance between the second end of the third folded edge 113 and the side surface of the first transition section 114 facing the third folded edge 113 is L1. Among them, the relationship between L1 and h satisfies the formula: 3 ≤ L1 / h ≤ 100. It should be noted that the groove depth direction refers to Figures 3 to 4 the "up and down" direction indicated by the arrow in Figures 3 to 4 ; the third folded edge 113 extends along the up and down direction, the second end of the third folded edge 113 is located at the lower end of the third folded edge 113, the first transition section 114 is located at the lower end of the folded edge structure, and L1 is the distance between the lower end of the third folded edge 113 and the lowest point of the upper surface of the first transition section 114. Among them, the lower end refers to the end along Figures 3 to 4 the direction of "down" indicated by the arrow in Figures 3 to 4 , and the upper surface refers to Figures 3 to 4 the surface on the side of the direction of "up" indicated by the arrow in Figures 3 to 4 ; the units of both L1 and h are mm. The larger h is, the larger the bending arc corresponding to the first transition section 114 between the second folded edge 112 and the first folded edge 111 is, and the higher the intersection line of the first transition section 114 with the first folded edge 111 and the second folded edge 112 is. As Figure 4 shown, the dimension L2 of the arc segment between the intersection line and the lowest point of the upper surface of the first transition section 114 in the up and down direction is larger, and the dimension of the corresponding spacing groove 117 of this arc segment in the width direction gradually decreases from top to bottom. If the third folded edge 113 extends into the position corresponding to this arc segment, it will affect the folding and bending forming of the second folded edge 112 and the first folded edge 111. Therefore, at this time, L1 needs to be appropriately increased. However, if L1 is increased too much, it will result in overdesign and waste of space.

[0052] Therefore, by setting the ratio L1 / h of the distance L1 between the second end of the third folded edge 113 and the first transition section 114 to the body thickness h of the edge sealing structure 102 to take values between 3 and 100, it is possible to avoid the second folded edge 112 from warping relative to the first folded edge 111, ensure the smooth forming of the folding and bending when the second folded edge 112 and the first folded edge 111 are folded, reduce the forming difficulty, and avoid overdesign, thereby saving space and materials.

[0053] In one embodiment, along the groove depth direction of the spacing groove 117, the value range of the maximum distance L1 between the second end of the third folded edge 113 and the side surface of the first transition section 114 facing the third folded edge 113 is: 0.6 mm ≤ L1 ≤ 50 mm. If L1 is less than 0.6 mm, the end of the third folded edge 113 is too close to the first transition section 114, resulting in the third folded edge 113 extending into the bending area of the first transition section 114. The third folded edge 113 interferes with the folding and bending of the second folded edge 112 relative to the first folded edge 111, causing the second folded edge 112 to be non-parallel to the first folded edge 111, and the second folded edge 112 warps away from the main body area 101. The fit between the folded edges of the edge sealing structure 102 is poor, and the size occupied by the edge sealing structure 102 in the width direction increases, which is not conducive to reducing the overall size of the battery cell and is not conducive to the stacking of the battery cell in the battery pack. If L1 is greater than 50 mm, the end of the third folded edge 113 is too far from the first transition section 114. On the one hand, it is necessary for the first folded edge 111 and the second folded edge 112 to extend downward for too long a distance, wasting materials and space. On the other hand, it will cause the size of the third folded edge 113 extending into the spacing groove 117 to be too short, and the third folded edge 113 is prone to warping under the action of the bending rebound force, and the fit between the third folded edge 113 and the first folded edge 111 is poor.

[0054] Therefore, by setting L1 to take values in the range of 0.6 mm to 50 mm, it is ensured that the end of the third folded edge 113 has a suitable distance from the lowest point of the upper surface of the first transition section 114, which can not only ensure the smooth folding and forming of the second folded edge 112 and the first folded edge 111 when they are folded against each other, avoid the warping of the second folded edge 112, but also avoid the warping of the third folded edge 113, ensure the fit between the folded edges of the edge sealing structure 102, and can also avoid over-design, thereby saving space and materials.

[0055] In one embodiment, the edge sealing structure 102 further includes: a connecting section 115, the connecting section 115 is connected between the main body area 101 and the first folded edge 111, the connecting section 115 is arranged at an angle with the first folded edge 111, and the first folded edge 111 is spaced from the main body area 101. It should be noted that the encapsulation film 1 is provided with punching pits for placing the electrode group, and the punching pits are weak areas on the encapsulation film 1. By setting that the edge sealing structure 102 further includes a connecting section 115 connected between the main body area 101 and the first folded edge 111, the first folded edge 111 is spaced from the main body area 101, ensuring that a certain length is left for the lead-out end of the encapsulation film 1 located outside the electrode group, preventing the bending structure from being bent and pulled to affect the fit between the electrode group and the encapsulation film 1, and making the bending structure away from the weak area of the punching pit, thereby improving the safety performance of the battery cell.

[0056] In one embodiment, the connecting section 115 is perpendicular to the first folded edge 111, and the distance between the first folded edge 111 and the main body area 101 along the horizontal direction is C, wherein 1mm≤C≤30mm. The horizontal direction is perpendicular to the up-down direction; further combined Figures 3 to 4 As shown, the edge sealing structure 102 is located on both sides of the width direction of the battery cell, and the horizontal direction refers to the side along the Figures 3 to 4 The middle arrow indicates the "width direction". By setting the connecting section 115 and the first folded edge 111, the first folded edge 111 extends in the horizontal direction. At the same time, by limiting the spacing C between the first folded edge 111 and the main area 101 in the horizontal direction to be in the range of 1mm to 30mm, it can prevent the first folded edge 111 from being too close to the main area 101, thereby ensuring that the lead-out end of the edge sealing structure 102 located outside the electrode group has a certain length, preventing the edge sealing structure 102 from bending and pulling to affect the electrode group, and making the bending structure away from the weak part of the pit, thereby improving the safety performance of the battery cell, and preventing the first folded edge 111 from being too far from the main area 101, resulting in the edge sealing structure 102 being too large in the width direction, thereby achieving the purpose of reducing the overall size of the battery cell, improving the space utilization rate inside the battery pack, and facilitating the stacking and fixing of the battery cell.

[0057] In one embodiment, the connection section 115 and the first folded edge 111 are transitionally connected by a third transition section, the third transition section is in an arc shape, and the radius of the arc of the third transition section is R, wherein the value range of R is: 0.2mm≤R≤C. The connection section 115 and the first folded edge 111 are transitionally connected by an arc to ensure a smooth transition and avoid sharp corners from stabbing adjacent structures. At the same time, by setting the radius R of the circle where the arc of the third transition section is located to be between 0.2mm and C, it is possible to avoid the difficulty of bending and shaping the first folded edge 111 relative to the connection section 115 due to too small a fillet, and to avoid the bending and pulling at the packaging due to too large a fillet, which affects the fit between the pole group and the packaging film, and to keep the bent structure away from the weak area of ​​the pit, thereby improving the safety performance of the battery cell.

[0058] In one embodiment, further combining Figure 4 As shown, along the thickness direction of the battery cell, the main body region 101 has a first surface 1011 and a second surface 1012 that are arranged opposite to each other, the distance from the first transition section 114 to the first surface 1011 is smaller than the distance from the first transition section 114 to the second surface 1012, and the shortest distance between the first transition section 114 and the first surface 1011 is h1, where h1≥0.1mm. The thickness direction refers to Figure 4The direction of "up and down" pointed by the arrow in the figure. It should be noted that both the first surface 1011 and the second surface 1012 are large surfaces of the battery cell; the first folded edge 111 is located on the side of the connecting section 115 close to the first surface 1011, the first surface 1011 is located on the lower side of the main body area 101, and the first folded edge 111 is bent downward relative to the connecting section 115, that is, the first folded edge 111 is bent in the direction close to the first surface 1011 relative to the connecting section 115; h1 is the vertical distance along the thickness direction of the battery cell between the lowest point of the lower surface of the first transition section 114 and the first surface 1011.

[0059] By setting the first folded edge 111 on the side of the connecting section 115 close to the first surface 1011, the first transition section 114 connected to the end of the first folded edge 111 far from the connecting section 115 is the part of the edge-sealing structure 102 closest to the first surface 1011. At the same time, by defining that the shortest distance h1 between the first transition section 114 and the first surface 1011 is greater than or equal to 0.1 mm, it is ensured that there is a certain interval between the end of the edge-sealing structure 102 close to the first surface 1011 and the first surface 1011 along the thickness direction of the battery cell, ensuring that the edge-sealing structure 102 does not protrude from the main body area 101 along the thickness direction of the battery cell, avoiding affecting the stacking of the battery cells in the whole package and improving the space utilization rate inside the battery pack.

[0060] In one embodiment, along the thickness direction of the battery cell, the size of the second folded edge 112 is larger than that of the first folded edge 111. The second folded edge 112 and the third folded edge 113 are connected by a second transition section 116. The distance between the second transition section 116 and the second surface 1012 along the thickness direction of the battery cell is h2, where h2≥0.1 mm. h2 is the vertical distance along the thickness direction of the battery cell between the highest point of the upper surface of the second transition section 116 and the first surface 1011. By setting that along the thickness direction of the battery cell, the size of the second folded edge 112 is larger than that of the first folded edge 111, the upper end of the second folded edge 112 is higher than the upper end of the first folded edge 111. Then the second transition section 116 connected to the upper end of the second folded edge 112 is the part of the edge-sealing structure 102 closest to the second surface 1012 along the thickness direction of the battery cell. By defining that the distance h2 between the second transition section 116 and the second surface 1012 along the thickness direction of the battery cell is greater than or equal to 0.1 mm, it is ensured that there is a certain interval between the end of the edge-sealing structure 102 close to the second surface 1012 and the second surface 1012 along the thickness direction of the battery cell, ensuring that the edge-sealing structure 102 does not protrude from the main body area 101 along the thickness direction of the battery cell, avoiding affecting the stacking of the battery cells in the whole package and improving the space utilization rate inside the battery pack.

[0061] Process the edge sealing structure of the battery cells with different parameter values of L / h and L1 / h to verify the influence of different values of L / h and L1 / h on the battery cells. The verification results are described below.

[0062] Table 1 Influence of Different Values of L / h and L1 / h on the Battery Cells

[0063]

[0064] As can be seen from Table 1, for the battery cells of Embodiment 1 to Embodiment 6, the values of L / h are all in the range of 6 to 100, and the values of L1 / h are all in the range of 3 to 100, that is, the values of L / h and L1 / h are both within the range defined in this application. Among them, L / h of the battery cell in Embodiment 1 is on the lower limit side, L1 / h of the battery cell in Embodiment 2 is on the lower limit side, and L / h and L1 / h of the battery cells in Embodiment 3 to Embodiment 6 are all conventional values. The edge sealing structures of the battery cells in Embodiment 1 to Embodiment 6 are successfully formed without failure. For the battery cell of Comparative Case 1, the value of L / h is 5.80, which is less than 6, and L / h exceeds the lower limit and is not within the range defined in this application. During the flanging process of the edge sealing structure, there are difficulties in flanging, the flanging warps, and the shape after bending is uncontrollable. For the battery cell of Comparative Case 2, the value of L1 / h is 2.90, which is less than 3, and L1 / h exceeds the lower limit and is not within the range defined in this application. During the flanging process of the edge sealing structure, there are difficulties in flanging, the flanging warps, and the shape after bending is uncontrollable.

[0065] From the above verification results, it can be seen that when the value of L / h is not within the range defined in this application, even if the values of L and h are within the range defined in this application, the edge sealing structure 102 of the battery cell will fail, and problems such as difficulties in flanging, flanging warping, and uncontrollable shape will occur. Specifically, the warping angle of the third flanging 113 is too large, and the third flanging 113 comes out of the spacer groove. In addition, if L / h is greater than 100, although there are no such problems, the dimension of the third flanging 113 extending into the spacer groove 117 is too large, resulting in overdesign, wasting space and materials. Therefore, when the ratio L / h between the dimension L of the third flanging 113 extending into the spacer groove 117 and the body thickness h of the edge sealing structure 102 takes a value of 113 between 6 and 100, it can ensure that the third flanging 113 does not warp and that the third flanging 113 does not come out of the spacer groove 117, avoiding problems such as difficulties in flanging, flanging warping, and uncontrollable shape, and ensuring reasonable design and material saving.

[0066] In addition, it can also be seen from the above verification results that when the value of L1 / h is not within the range defined in the present application, even if the values of L1 and h are within the range defined in the present application, the edge-sealing structure 102 of the battery cell will fail, and problems such as difficult flanging, warping during flanging, and uncontrollable shape will occur. Specifically, there are phenomena such as the second flanging 112 warping away from the main body area 101, difficult bending, and poor fit between the various flanges of the edge-sealing structure 102. In addition, if L1 / h is greater than 100, there will be over-design, wasting space and materials. Therefore, when the ratio L1 / h between the distance L1 between the second end of the third flanging 113 and the first transition section 114 and the body thickness h of the edge-sealing structure 102 takes a value between 3 and 100, it can not only avoid the warping of the second flanging 112 relative to the first flanging 111, ensure the smooth forming of the bending when the second flanging 112 and the first flanging 111 are folded against each other, reduce the forming difficulty, but also ensure the fit between the various flanges of the edge-sealing structure 102, avoid problems such as difficult flanging, warping during flanging, and uncontrollable shape, and avoid over-design, thereby saving space and materials.

[0067] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, including: the above-mentioned battery cell. Preferably, the number of battery cells is multiple; the battery cells are lithium-ion battery cells.

[0068] 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 all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that: include: Pole group; A packaging film comprises a main body area and an edge sealing structure, wherein the main body area corresponds to the pole group, the edge sealing structure is connected to at least one side of the main body area, the edge sealing structure comprises a first folded edge, a second folded edge and a third folded edge formed by bending, the second folded edge is located on a side of the first folded edge away from the main body area, the first folded edge and the second folded edge are arranged opposite to each other and a spacing groove is formed therebetween, the first end of the third folded edge is connected to the second folded edge and the second end extends into the spacing groove, and along the groove depth direction of the spacing groove, the dimension of the third folded edge extending into the spacing groove is L; the main body thickness of the edge sealing structure is h, wherein L and h satisfy the relationship: 6≤L / h≤100.

2. The battery cell according to claim 1, characterized in that: The value range of the main body thickness h of the edge sealing structure is: 0.2mm≤h≤6mm; And / or, along the groove depth direction of the spacing groove, the dimension L of the third folded edge extending into the spacing groove has a value range of: 1.2 mm ≤ L ≤ 50 mm.

3. The battery cell according to claim 1, characterized in that: The first folded edge is connected to the second folded edge via a first transition section, and the second end of the third folded edge is spaced apart from the first transition section along the groove depth direction of the spacing groove.

4. The battery cell according to claim 3, characterized in that: Along the groove depth direction of the spacing groove, the maximum distance between the second end of the third folded edge and the side surface of the first transition section facing the third folded edge is L1, wherein L1 and h satisfy the relationship: 3≤L1 / h≤100.

5. The battery cell according to claim 3, characterized in that: The extension directions of the first folded edge, the second folded edge and the third folded edge are all parallel to the thickness direction of the battery core.

6. The battery cell according to claim 5, characterized in that: The edge sealing structure further includes: a connecting section, wherein the connecting section is connected between the main body area and the first folded edge, the connecting section and the first folded edge are arranged at an angle, and the first folded edge and the main body area are arranged at an interval.

7. The battery cell according to claim 6, characterized in that: The connecting section is perpendicular to the first folded edge, and a distance between the first folded edge and the main body area in a horizontal direction is C, wherein 1mm≤C≤30mm.

8. The battery cell according to any one of claims 3 to 7, characterized in that: Along the thickness direction of the battery core, the main body area has a first surface and a second surface arranged opposite to each other, the distance from the first transition section to the first surface is smaller than the distance from the first transition section to the second surface, and the shortest distance between the first transition section and the first surface is h1, where h1≥0.1mm.

9. The battery cell according to claim 8, characterized in that: Along the thickness direction of the battery cell, the size of the second folded edge is larger than the size of the first folded edge, the second folded edge is connected to the third folded edge by a second transition section, and the distance between the second transition section and the second surface along the thickness direction of the battery cell is h2, where h2≥0.1mm.

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

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