Battery cell structure and battery
By designing a fixing adhesive paper with a void in the cell structure, the problem of increased cell thickness was solved, thereby improving battery energy density and ensuring mechanical performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG LIWINON ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2025-06-24
- Publication Date
- 2026-07-14
AI Technical Summary
In existing polymer lithium-ion batteries, the thickness of the tab welding area is the largest due to the adhesive tape being pasted on the cell surface, which increases the overall thickness of the cell and reduces the energy density of the lithium-ion battery.
Design a battery cell structure in which the fixing adhesive tape has a void portion, which is arranged opposite to the electrode tab and offset along the thickness direction of the battery cell to reduce the superposition of the fixing adhesive tape in the thickness direction. Combined with an appropriate ratio of projected area and perimeter, ensure the bonding strength and prevent the battery cell from shifting.
It effectively reduces the overall thickness of the cell structure, improves the energy density of the battery, and ensures mechanical performance during the drop test, preventing cell movement.
Smart Images
Figure CN224501976U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to a cell structure and a battery. Background Technology
[0002] Existing polymer lithium-ion batteries generally use aluminum-plastic film as the packaging film for the bare cells to protect them and prevent internal electrolyte leakage. To ensure the safety performance of lithium-ion batteries, such as during drop tests, hot-melt double-sided adhesive is used to fix the bare cells and the aluminum-plastic film together, preventing the bare cells from shifting within the packaging film.
[0003] In existing polymer lithium-ion batteries, the cell consists of a bare cell, tabs, and adhesive tape. The bare cell is formed by winding positive and negative current collectors and a separator. The tabs are fixedly connected to the current collectors by ultrasonic welding or laser welding. After the cell is wound, the adhesive tape is pasted onto the outer surface of the cell. The area with the largest thickness dimension in the cell is the region where the current collectors and tabs are welded. In this region, the current collectors and tabs are stacked along the thickness direction, resulting in the maximum thickness.
[0004] The adhesive tape is usually pasted on the surface of the battery cell. This causes the tape to overlap with the electrode welding area, which further increases the overall thickness of the battery cell and reduces the energy density of the lithium-ion battery. Utility Model Content
[0005] The purpose of this invention is to provide a cell structure to solve the problem that the winding core in the prior art reduces the energy density of lithium-ion batteries; this invention also provides a battery using this cell structure.
[0006] To achieve the above objectives, this utility model provides a battery cell structure, including a battery cell body, a tab, and a fixing adhesive tape. The tab is located at one end of the length direction of the battery cell body and is fixedly connected to the battery cell body.
[0007] The fixing adhesive tape is applied to the surface of the battery cell body. The fixing adhesive tape has a gap-avoiding portion, which is disposed opposite to the electrode tab along the thickness direction of the battery cell body.
[0008] Along the thickness direction of the battery cell body, the projected area of the fixing adhesive tape on the battery cell body is S, in mm. 2 The mass of the battery cell body is M, in g, and satisfies: S / M≥15.
[0009] Optionally, 15 ≤ S / M ≤ 50.
[0010] Optionally, the perimeter of the fixing tape is C, in mm, and satisfies: C / M≥3.
[0011] Optionally, 3 ≤ C / M ≤ 8.
[0012] Optionally, the cell structure further includes a finishing adhesive tape, which is bonded and fixed to the cell body, and the fixing adhesive tape and the finishing adhesive tape have a gap along the width direction of the cell body.
[0013] Optionally, the cell structure further includes head wrapping and tail wrapping, which are glued and fixed to both ends of the cell body along the length direction. Along the length direction of the cell body, there are gaps between the head wrapping and the fixing adhesive paper, and between the tail wrapping and the fixing adhesive paper.
[0014] Optionally, along the length of the battery cell body, the distance between the head wrapping adhesive and the tail wrapping adhesive is V, and the maximum size of the fixing adhesive paper is Z, where Z≤V.
[0015] Optionally, the fixing adhesive paper includes a substrate layer, a pressure-sensitive adhesive layer, and a heat-sensitive adhesive layer. The pressure-sensitive adhesive layer is provided on one side of the substrate layer and the heat-sensitive adhesive layer is provided on the other side. The pressure-sensitive adhesive layer is connected to the battery cell body.
[0016] Optionally, along the length direction of the battery cell body, the fixing adhesive tape includes a first part and a second part that are connected to each other. The first part and the clearance part are arranged side by side along the width direction of the battery cell body. The peeling force of the first part is F1, and the peeling force of the second part is F2, satisfying: 1>F1 / (F1+F2)≥0.1.
[0017] Optionally, the first part and the second part are integrally formed; or, the first part and the second part are separately formed.
[0018] This utility model also provides a battery, including a cell structure and a packaging shell covering the cell structure, wherein the cell structure is the cell structure described in any of the above technical solutions, and the fixing adhesive tape is used to bond the cell body to the packaging shell.
[0019] Compared with the prior art, the beneficial effects of this utility model embodiment of a battery cell structure and battery are as follows: the clearance portion of the fixing tape corresponds to the tab along the thickness direction of the battery cell body. After the fixing tape is pasted on the battery cell body, the clearance portion ensures that the thickness of the fixing tape does not overlap at the connection point between the tab and the battery cell body, thereby reducing the overall thickness of the battery cell structure and improving the energy density of the battery; in addition, the ratio of the projected area of the fixing tape along the thickness direction of the battery cell body to the mass of the battery cell body is greater than or equal to 15mm². 2 / g can prevent the adhesive tape from having too small a projected area, which would result in insufficient adhesion between the battery cell and the packaging shell, thus preventing the battery cell structure from shifting and ensuring the mechanical performance of the battery when it is dropped from the drum. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the battery cell structure of this utility model;
[0021] Figure 2 This is a schematic diagram illustrating the thickness gain of the battery cell structure of this utility model compared to the battery cell structure of the prior art;
[0022] Figure 3 yes Figure 1 A schematic diagram of the adhesive tape used to fix the battery cell structure;
[0023] Figure 4 This is a schematic diagram of the reverse orientation of the clearance portion of the fixing adhesive paper in the battery cell structure of this utility model;
[0024] Figure 5 This is a schematic diagram of the battery cell structure of this utility model, in which the fixing adhesive paper is two concave shapes.
[0025] Figure 6 This is a schematic diagram of the fixing adhesive paper of the battery cell structure of this utility model, which is a single W-shaped structure.
[0026] Figure 7 This is another structural schematic diagram of the battery cell structure of this utility model, where the fixing adhesive paper is a single W shape;
[0027] Figure 8 This is a schematic diagram of the structure of the battery cell of this utility model, in which the fixing adhesive paper is a single concave shape.
[0028] In the diagram, 1. Battery cell body, 2. Electrode tab, 3. Fixing adhesive tape, 31. First part, 32. Second part, 33. Air gap, 34. Substrate layer, 35. Pressure-sensitive adhesive layer, 36. Heat-sensitive adhesive layer, 4. Tail tape, 5. Head wrapping adhesive, 6. Tail wrapping adhesive, 7. Packaging shell. Detailed Implementation
[0029] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.
[0030] A preferred embodiment of the battery cell structure of this utility model is as follows: Figures 1 to 8 As shown, the battery cell structure includes a battery cell body 1, a tab 2, and a fixing adhesive tape 3. The battery cell body 1 is formed by winding positive and negative current collectors and a separator. The tab 2 is located at one end of the length direction of the battery cell body 1 and is welded and fixed to the positive and negative current collectors of the battery cell body 1.
[0031] The fixing tape 3 is a hot melt adhesive. It is applied to the surface of the battery cell body 1 and used to secure the battery cell body 1 to the packaging shell 7, ensuring the battery's mechanical properties during a drop test and preventing the battery cell body 1 from shifting within the packaging shell 7. The projected area of the fixing tape 3 on the battery cell body 1 along its thickness direction is S, in mm. 2 The mass of the battery cell body 1 is M, in grams, and satisfies: S / M≥15. Meeting this formula ensures the minimum projected area of the adhesive tape 3, increases the bonding strength between the battery cell body 1 and the packaging shell 7, thereby preventing the battery cell body 1 from shifting and improving the mechanical performance of the battery cell.
[0032] The fixing tape 3 has a clearance portion 33. Along the thickness direction of the cell body 1, the clearance portion 33 is positioned opposite to the tab 2. That is, the projection of the tab 2 along the thickness direction of the cell body 1 is located in the clearance portion 33 of the fixing tape 3, and is offset from the projection of the fixing tape 3 along the thickness direction of the cell body 1. The position where the tab 2 is welded to the cell body 1 is the position where the cell structure is thickest. By setting the clearance portion 33, the fixing tape 3 avoids the last position of the cell structure, thereby reducing the overall thickness of the cell structure and increasing the energy density.
[0033] In this embodiment, as Figure 1 As shown, there are two fixing tapes 3, each fixing tape 3 is L-shaped, and the two fixing tapes 3 are spaced apart along the width direction of the battery cell body 1. The clearance part 33 is a rectangular notch at the corner of the fixing tape 3. The direction of the clearance part 33 of the two fixing tapes 3 can be the same or opposite.
[0034] like Figure 1 As shown, the maximum dimension of the clearance portion 33 in the width direction is W, the width of the electrode tab 2 is A, and the gap between the clearance portion 33 and the electrode tab 2 in the length direction is Y, satisfying: W>A, and Y>0, so as to ensure that the projections of the fixing adhesive tape 3 and the electrode tab 2 along the thickness direction of the battery cell body 1 are staggered.
[0035] The thickness of the fixing tape 3 is J, the thickness of the battery cell body 1 is H, and the thickness of the electrode tab 2 is I. For example... Figure 2 As shown in (a), in the prior art, after the adhesive tape 3 is attached to the tab 2 of the battery cell structure, the maximum thickness of the battery cell structure is (I+J). In this embodiment, as... Figure 2As shown in (b), after the fixing tape 3 is provided with the clearance part 33 and is pasted on the cell body 1, the maximum thickness of the cell structure is the maximum value of the sum of the thickness H of the cell body 1 and the thickness J of the fixing tape 3 and the thickness I of the tab 2, MAX[I,(H+J)]. Therefore, in this embodiment, the thickness gain of the cell structure = (I+J)-MAX[I,(H+J)], and the thickness gain is the thickness difference between the cell structure of this embodiment and the existing cell structure.
[0036] The thickness benefits of the battery cell structure in this utility model are shown in Table 1 below. The battery cell mechanical tests include 5 cells each of roller, micro-drop, free drop, 1m directional drop, and 1.5m directional drop tests.
[0037]
[0038] Table 1
[0039] In other embodiments, such as Figure 6 , Figure 7 and Figure 8 As shown, there can be only one adhesive tape 3, which has a concave or W-shaped structure, and the rectangular notch of the adhesive tape 3 forms a clearance portion 33; or, as... Figure 4 and Figure 5 As shown, there can also be two fixing tapes 3. A single fixing tape 3 has a concave structure or an L-shaped structure, and the two fixing tapes 3 are spaced apart along the width direction of the battery cell body 1.
[0040] The clearance portion 33 of the fixing tape 3 in this cell structure corresponds to the tab 2 along the thickness direction of the cell body 1. After the fixing tape 3 is pasted on the cell body 1, the clearance portion 33 ensures that the dimension in the thickness direction at the connection position between the tab 2 and the cell body 1 does not overlap with the thickness of the fixing tape 3, thereby reducing the overall thickness of the cell structure and improving the energy density of the battery. In addition, the ratio of the projected area of the fixing tape 3 along the thickness direction of the cell body to the mass of the cell body 1 is greater than or equal to 15 mm2 / g. This can prevent the projected area of the fixing tape 3 from being too small, which would result in insufficient adhesion between the cell body 1 and the packaging shell 7, prevent the cell structure from shifting, and ensure the mechanical performance of the battery when dropped from a drum.
[0041] In some embodiments, 15 mm² / g ≤ S / M ≤ 50 mm² / g.
[0042] If S / M is less than 15 mm² / g, the bonding area of the fixing tape 3 will be too small, resulting in weak adhesion to the battery cell body 1. This will prevent the battery cell structure from being firmly fixed to the packaging shell 7, causing the battery cell body 1 to move when the battery roller falls. If S / M is greater than 50 mm² / g, the bonding area of the fixing tape 3 will be too large, which will cause air bubbles to form on the outer surface of the battery cell body 1, resulting in poor flatness of the battery cell and increasing the total weight of the battery cell structure.
[0043] In some embodiments, the perimeter of the fixing tape 3 is C, in mm, which satisfies: C / M≥3.
[0044] The ratio of the perimeter of the fixing tape 3 to the mass of the battery cell body 1 is greater than or equal to 3.0 mm / g. This can prevent the projected area of the fixing tape 3 from being too small, which would result in insufficient adhesion between the battery cell body 1 and the packaging shell 7. This also prevents the battery cell structure from shifting within the packaging shell and ensures the mechanical performance of the battery when it is dropped from the drum.
[0045] In some embodiments, 3 ≤ C / M ≤ 8.
[0046] If C / M is less than 3mm / g, the bonding area of the fixing tape 3 will be too small, resulting in weak adhesion to the battery cell body 1. This will prevent the battery cell structure from being firmly fixed to the packaging shell 7, and the battery cell body 1 will move when the battery roller falls. If C / M is greater than 8mm / g, the shape of the fixing tape 3 will be complex and there will be too many splicing positions, making the bonding and fixing process complicated, even if the bonding area of the fixing tape 3 is sufficient.
[0047] In some embodiments, the cell structure further includes a finishing adhesive tape 4, which is bonded and fixed to the cell body 1, and the fixing adhesive tape 3 and the finishing adhesive tape 4 have a gap along the width direction of the cell body 1.
[0048] The finishing tape 4 and the fixing tape 3 have a gap along the width direction of the cell body 1, so that there is no overlap between the finishing tape 4 and the fixing tape 3, thus avoiding increasing the maximum thickness of the cell structure after they overlap. Figure 1 As shown, there is a gap E3 between the finishing tape 4 and the fixing tape 3, a gap E2 between the two fixing tapes 3, and a gap E1 between the fixing tape 3 and the width direction edge of the battery cell body 1, satisfying: E1>0, E2>0, E3>0.
[0049] In some embodiments, the cell structure further includes a head wrapping adhesive 5 and a tail wrapping adhesive 6, which are attached and fixed to both ends of the cell body 1 along the length direction. Along the length direction of the cell body 1, there are gaps between the head wrapping adhesive 5 and the fixing adhesive paper 3, and between the tail wrapping adhesive 6 and the fixing adhesive paper 3.
[0050] Head tape and tail tape are used to fix the two ends of the battery cell body 1 along its length, such as... Figure 1As shown, the gap between the head adhesive tape and the fixed adhesive tape 3 is B, and the gap between the tail wrapping tape 6 and the fixed adhesive tape 3 is G. B>0 and G>0, so that the head adhesive tape and the tail adhesive tape do not overlap with the fixed adhesive tape 3, thus avoiding the increase in the maximum thickness of the battery cell structure after overlap.
[0051] In some embodiments, along the length of the cell body 1, the distance between the head wrapping adhesive 5 and the tail wrapping adhesive 6 is V, and the maximum size of the fixing adhesive paper 3 is Z, where Z≤V.
[0052] like Figure 1 As shown, the distance V between the head wrapping 5 and the tail wrapping 6 is greater than or equal to the maximum size Z of the fixing tape 3, which can ensure that both the head wrapping 5 and the tail wrapping 6 have gaps with the fixing tape 3, avoiding the increase in the maximum thickness of the battery cell structure due to mutual overlap.
[0053] In some embodiments, the fixing adhesive tape 3 includes a substrate layer 34, a pressure-sensitive adhesive layer 35, and a heat-sensitive adhesive layer 36. The substrate layer 34 has a pressure-sensitive adhesive layer 35 on one side and a heat-sensitive adhesive layer 36 on the other side. The pressure-sensitive adhesive layer 35 is connected to the battery cell body 1.
[0054] The fixing tape 3 is formed by stacking a substrate layer 34, a pressure-sensitive adhesive layer 35, and a heat-sensitive adhesive layer 36. The pressure-sensitive adhesive layer 35 has pressure-sensitive characteristics and can be bonded and fixed to the battery cell body 1 by applying pressure, which is convenient. The heat-sensitive adhesive layer 36 is located on the side of the substrate layer 34 away from the battery cell body 1 and is used to contact the packaging shell 7. It can be bonded and fixed to the packaging shell 7 by heat fusion. The fixing tape 3 is a roll of material with a uniform size and irregular shape, which is made by die-cutting or laser cutting.
[0055] In some embodiments, along the length direction of the battery cell body 1, the fixing adhesive tape 3 includes a first part 31 and a second part 32 connected to each other. The first part 31 and the clearance part 33 are arranged side by side along the width direction of the battery cell body 1. The peeling force of the first part 31 is F1, and the peeling force of the second part 32 is F2, satisfying: 1>F1 / (F1+F2)≥0.1.
[0056] After the peel force F1 of the first part 31 and F2 of the second part 32 satisfy the above formula, it can be ensured that the first part 31, the second part 32 and the cell body 1 have sufficient peel force respectively. This can avoid the situation where one of the first part 31 or the second part 32 is a slender structure, resulting in insufficient adhesion between part of the fixing tape 3 and the cell body 1. At the same time, while ensuring the adhesion of the fixing tape 3, the energy density of the cell structure is improved by the clearance part 33. Figure 1 As shown, the width of the first part 31 is X, and the length of the first part 31 is Y.
[0057] In some embodiments, the first part 31 and the second part 32 are integrally formed; or, the first part 31 and the second part 32 are separate parts.
[0058] When the first part 31 and the second part 32 are integrally formed, the fixing tape 3 can be pasted and fixed at one time, simplifying the pasting process; when the first part 31 and the second part 32 are separately formed, the second part 32 can be formed by attaching additional tape, and the second part 32 can be pasted separately according to different sizes of the battery cell body 1, which is highly adaptable.
[0059] This utility model also provides an embodiment of a battery, including a cell structure and a packaging shell 7 covering the cell structure. The fixing adhesive tape 3 is used to attach and connect the cell body 1 and the packaging shell 7. The specific structure of the cell structure is the same as that of the cell structure in any of the above embodiments, and will not be described again here.
[0060] In summary, this utility model embodiment provides a cell structure and battery, in which the clearance portion of the fixing tape corresponds to the tab along the thickness direction of the cell body. After the fixing tape is pasted on the cell body, the clearance portion ensures that the thickness of the fixing tape does not overlap at the connection point between the tab and the cell body, thereby reducing the overall thickness of the cell structure and improving the energy density of the battery. In addition, the ratio of the projected area of the fixing tape to the mass of the cell body is greater than or equal to 15mm². 2 / g can prevent the adhesive tape from having too small a projected area, which would result in insufficient adhesion between the battery cell and the packaging shell, thus preventing the battery cell structure from shifting and ensuring the mechanical performance of the battery when it is dropped from the drum.
[0061] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.
Claims
1. A battery cell structure, characterized in that, It includes a battery cell body (1), a tab (2) and a fixing tape (3). The tab (2) is located at one end of the length direction of the battery cell body (1) and is fixedly connected to the battery cell body (1). The fixing tape (3) is applied to the surface of the battery cell body (1). The fixing tape (3) has a clearance portion (33). Along the thickness direction of the battery cell body (1), the clearance portion (33) is arranged opposite to the electrode tab (2). Along the thickness direction of the battery cell body (1), the projected area of the fixing adhesive tape (3) on the battery cell body (1) is S, in mm. 2 The mass of the battery cell body (1) is M, in g, and satisfies: S / M≥15.
2. The cell structure according to claim 1, characterized in that, 15≤S / M≤50.
3. The cell structure according to claim 1 or 2, characterized in that, The perimeter of the fixing tape (3) is C, in mm, and satisfies: C / M≥3.
4. The cell structure according to claim 3, characterized in that, 3≤C / M≤8.
5. The cell structure according to claim 1 or 2, characterized in that, The cell structure also includes a finishing adhesive tape (4), which is bonded and fixed to the cell body (1). The fixing adhesive tape (3) and the finishing adhesive tape (4) have a gap along the width direction of the cell body (1).
6. The cell structure according to claim 1 or 2, characterized in that, The cell structure also includes a head wrapping adhesive (5) and a tail wrapping adhesive (6). The head wrapping adhesive (5) and the tail wrapping adhesive (6) are attached and fixed to both ends of the cell body (1) along the length direction. Along the length direction of the cell body (1), there are gaps between the head wrapping adhesive (5) and the fixing adhesive paper (3) and between the tail wrapping adhesive (6) and the fixing adhesive paper (3).
7. The cell structure according to claim 6, characterized in that, Along the length of the battery cell body (1), the distance between the head wrapping adhesive (5) and the tail wrapping adhesive (6) is V, and the maximum size of the fixing adhesive paper (3) is Z, Z≤V.
8. The cell structure according to claim 1 or 2, characterized in that, The fixing adhesive tape (3) includes a substrate layer (34), a pressure-sensitive adhesive layer (35), and a heat-sensitive adhesive layer (36). The pressure-sensitive adhesive layer (35) is provided on one side of the substrate layer (34), and the heat-sensitive adhesive layer (36) is provided on the other side. The pressure-sensitive adhesive layer (35) is connected to the battery cell body (1).
9. The cell structure according to claim 1 or 2, characterized in that, Along the length of the battery cell body (1), the fixing adhesive tape (3) includes a first part (31) and a second part (32) connected to each other. The first part (31) and the clearance part (33) are arranged side by side along the width of the battery cell body (1). The peeling force of the first part (31) is F1, and the peeling force of the second part (32) is F2, satisfying: 1>F1 / (F1+F2)≥0.
1.
10. The cell structure according to claim 9, characterized in that, The first part (31) and the second part (32) are integrally formed; or the first part (31) and the second part (32) are separate parts.
11. A battery, characterized in that, The battery includes a battery cell structure and a packaging shell (7) covering the battery cell structure. The battery cell structure is the battery cell structure according to any one of claims 1-10. The fixing adhesive tape (3) is used to attach and connect the battery cell body (1) and the packaging shell (7).