Battery cell, battery pack, and vehicle

Abstract

The utility model discloses related to the technical field of power battery, and discloses a kind of battery cell, battery pack and vehicle, the device includes: including battery cell monomer and isolation layer;The isolation layer is covered in the battery cell monomer top surface, and isolation layer is equipped with multiple through holes arranged at interval according to preset trajectory in the area corresponding with the shoulder of battery cell monomer top surface, and the through hole is filled with structure glue for being connected with pressing strip.The technical scheme of the utility model can improve the pressing strip bonding quality, and guarantee the stability of battery work.

Description

Technical Field

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

[0002] In the industrial application of lithium-ion batteries, individual cells (such as square aluminum-cased cells and pouch cells) are rarely used alone. They need to be assembled into battery systems through a multi-level process of cells-modules-packs. Among these components, the pressure strip is a core structural component for cell assembly. Its core functions include: constraining the dispersed individual cells into a rigid whole, preventing collisions and friction caused by displacement during transportation and use (such as the bumps of new energy vehicles and the vibrations of energy storage devices), and preventing wear on the cell casing or damage to the sealing structure.

[0003] To achieve a reliable connection between the pressure strip and the battery cell, the existing technology generally adopts a through-hole adhesive bonding scheme: that is, a single large-area through-hole is opened on the top shoulder of the battery cell (away from the tab or the area avoiding the projection of the electrode core), structural adhesive is filled into the through-hole, and then the pressure strip is attached to the top surface of the battery cell. The fixation is achieved by the adhesion between the structural adhesive and the wall of the through-hole. The original intention of this scheme is to increase the adhesive contact area through the through-hole to ensure the connection strength.

[0004] However, as the requirements for cycle life, vibration reliability, and sealing safety of power batteries continue to increase, existing large-area through-hole bonding solutions are gradually revealing unavoidable technical defects, as follows: 1. Large-area through holes will significantly weaken the body material of the insulation layer, forming a weak area in the structure: When the cell is subjected to expansion force and vibration stress, the stress will concentrate at the edge of the through hole. Long-term use will easily lead to cracking of the insulation layer and affect the working stability of the battery.

[0005] 2. Large-area through holes have a large volume. During the adhesive application process, the adhesive is prone to local accumulation or gaps due to gravity and deviations in the adhesive application process, resulting in uneven adhesive layer thickness and affecting the bonding quality between the pressure strip and the battery cell. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this application is to provide a battery cell, battery pack and vehicle that can improve the bonding quality of the pressure strip and ensure the stability of battery operation.

[0007] In a first aspect, embodiments of this application provide a battery cell, including a battery cell unit and an insulating layer; the insulating layer is disposed on the top surface of the battery cell unit, and the insulating layer has a plurality of through holes arranged at intervals according to a preset trajectory in a region corresponding to the shoulder of the top surface of the battery cell unit, and the through holes are filled with structural adhesive for connection with the pressure strip.

[0008] In this embodiment, the large-area through-hole is divided into multiple through-holes arranged at preset intervals. This arrangement has two advantages: firstly, it preserves the integrity of the insulating layer material between adjacent through-holes, effectively resisting the expansion force and vibration impact of the battery cell and preventing the insulating layer from breaking and failing; secondly, compared to existing single large-area through-holes, the spaced through-holes of this invention have a smaller volume, and the adhesive amount in each hole can be precisely controlled through the dispensing process, improving the uniformity of the adhesive layer thickness, effectively avoiding incomplete connections, and ensuring reliable adhesion between the pressure strip and the battery cell.

[0009] In one embodiment, the plurality of through holes are arranged in a matrix along the length direction of the shoulder of the battery cell, and the center distance between two adjacent through holes is 1.2 to 3 times the diameter of the through hole.

[0010] In this embodiment, the matrix arrangement ensures that the vias are evenly distributed on the insulating layer. Combined with a center-to-center distance of 1.2 to 3 times the via diameter, this avoids both localized thinning of the material due to excessively close spacing between adjacent vias, which could lead to easily broken weak zones, and localized lack of adhesive support and stress concentration due to excessively large spacing. This ensures that the insulating layer retains sufficient and uniform body material, improving tear and deformation resistance and reducing the risk of loss of insulation protection due to insulating layer failure. Furthermore, the matrix-distributed adhesive layer evenly disperses curing shrinkage stress, preventing localized accumulation. Combined with a center-to-center distance of 1.2 to 3 times the via diameter, this further avoids mutual interference of shrinkage stress between adjacent adhesive layers, reducing the probability of gaps appearing between the insulating layer and the top surface of the battery cell. This ensures that the insulating layer remains tightly bonded to the battery cell, eliminating the risk of impurities intruding through gaps.

[0011] In one embodiment, the cross-sectional shape of the through hole is rectangular, circular, triangular, or oblong.

[0012] In this embodiment, circular through holes are suitable for high-precision processing equipment such as laser drilling and CNC drilling, and are especially suitable for flexible isolation layers such as PET and PP; rectangular and oblong through holes are more suitable for die-cutting processes, and can be mass-produced through customized molds, which are suitable for isolation layers with thicker thickness or stronger rigidity; triangular through holes can be achieved through etching or precision die-cutting, which are suitable for scenarios with special space requirements for the corners of the holes.

[0013] In one embodiment, the plurality of through holes are divided into at least two groups, each group of through holes is arranged along the width direction of the shoulder of the battery cell, and each group of through holes is connected by the same structural adhesive.

[0014] In this embodiment, compared to a single set of multiple through holes, the design of at least two sets upgrades the seal from single-area redundancy to multi-area independent redundancy, further improving the seal reliability.

[0015] In one embodiment, the total projected area of ​​the plurality of through holes on the top surface of the battery cell is greater than or equal to a preset area threshold.

[0016] In this embodiment, the preset area threshold is essentially a quantitative guarantee of the total adhesive capacity of the multi-hole structure, ensuring that the total adhesion of the adhesive layer meets the stress requirements.

[0017] Secondly, embodiments of this application provide a battery pack, including a pressure strip and the aforementioned battery cell, wherein the pressure strip is bonded and fixed to the top surface of the battery cell via the structural adhesive.

[0018] In one embodiment, one of the bottom surface of the pressure strip and the top surface of the battery cell is provided with a groove, and the other is provided with a protrusion that fits into the groove.

[0019] In this embodiment, the concave-convex gap fit can provide a physical positioning reference for the assembly of the pressure strip and the battery cell. Furthermore, the concave-convex fit can optimize the distribution of the adhesive layer through spatial morphology, thereby enhancing the mechanical interlocking and anti-overflow effect of the adhesive.

[0020] In one embodiment, the top surface of the battery cell is provided with a groove, the bottom surface of the pressure strip is provided with a protrusion that fits the groove with a gap, and the orthographic projection of the groove on the top surface of the battery cell covers the orthographic projection of the through hole on the top surface of the battery cell.

[0021] In this embodiment, since the orthographic projection of the groove on the top surface of the battery cell covers the orthographic projection of the through hole on the top surface of the battery cell, the adhesive can naturally flow into the groove on the top surface of the battery cell below while filling the through hole, ensuring that each groove is fully filled with adhesive.

[0022] In one embodiment, the roughness of the groove wall is greater than a preset roughness threshold.

[0023] In this embodiment, when the roughness of the groove wall exceeds a preset roughness threshold, tiny uneven textures will form on the wall surface. When the adhesive fills the groove, these textures can be embedded, forming an interlocking structure of adhesive teeth and groove wall textures. Compared to smooth groove walls that rely solely on planar contact, the actual adhesive contact area of ​​the rough groove wall is significantly increased, and the interfacial adhesion between the adhesive layer and the groove wall is significantly improved. This avoids the adhesive layer from detaching from the groove wall due to vibration or cell expansion, and strengthens the complete connection chain of pressure strip-adhesive layer-isolation layer-cell unit.

[0024] Thirdly, embodiments of this application provide a vehicle including the aforementioned battery pack.

[0025] This utility model has the following beneficial effects: This invention breaks down a large-area through-hole into multiple spaced-apart small-area through-holes. On one hand, the intact insulating layer material is retained between adjacent through-holes, effectively resisting the expansion force and vibration impact of the battery cell and preventing the insulating layer from breaking and failing. On the other hand, compared to existing single large-area through-holes, the spaced-apart through-holes in this invention have a smaller volume. By precisely controlling the amount of adhesive in each hole through the dispensing process, the uniformity of the adhesive layer thickness is improved, effectively avoiding incomplete connections and ensuring reliable adhesion between the pressure strip and the battery cell. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application will be described below.

[0027] Figure 1 This is a top view of the battery cell disclosed in an embodiment of this application.

[0028] Figure 2 This is a cross-sectional schematic diagram of one embodiment of the battery cell disclosed in this application.

[0029] Figure 3 This is a cross-sectional schematic diagram of another embodiment of the battery cell disclosed in this application.

[0030] Figure 4 This is a cross-sectional schematic diagram of another embodiment of the battery cell disclosed in this application.

[0031] Explanation of reference numerals in the attached figures: 1-Battery cell, 11-Groove; 2-Insulating layer, 21-Through hole; 3-Pressure strip, 31-Protrusion; 4-Structural adhesive. Detailed Implementation

[0032] The embodiments of this application are described below with reference to the accompanying drawings.

[0033] See Figure 1 and Figure 2 As shown, this application embodiment provides a battery cell, including a battery cell 1 and an insulating layer 2; the insulating layer 2 is covered on the top surface of the battery cell 1, and the insulating layer 2 has a plurality of through holes 21 arranged at preset intervals in the area corresponding to the shoulder of the top surface of the battery cell 1, and the through holes 21 are filled with structural adhesive 4 for connection with the pressure strip 3.

[0034] In this embodiment, the large-area through-holes in the prior art are divided into multiple through-holes 21 arranged at preset intervals. This arrangement serves two purposes: firstly, it preserves the integrity of the insulating layer 2 material between adjacent through-holes 21, effectively resisting the expansion force and vibration impact of the battery cell 1 and preventing the insulating layer 2 from breaking or failing. Secondly, compared to existing single large-area through-holes, the spaced through-holes 21 of this invention have a smaller volume. By precisely controlling the amount of adhesive in each hole through the dispensing process, the uniformity of the adhesive layer thickness is improved, effectively avoiding incomplete connections and ensuring reliable adhesion between the pressure strip 3 and the battery cell 1.

[0035] In a preferred embodiment, the plurality of through holes 21 are arranged in a matrix along the length direction of the shoulder of the battery cell 1, and the center distance between two adjacent through holes 21 is 1.2 to 3 times the diameter of the through hole 21.

[0036] The matrix arrangement ensures that the through holes 21 are evenly distributed on the isolation layer 2. Combined with a center distance of 1.2 to 3 times the hole diameter, this avoids the situation where the material is too small in some areas due to the close spacing of adjacent through holes 21, which would form weak zones that are prone to breakage. It also prevents the situation where there is no adhesive support in some areas and the stress is concentrated due to the large spacing. This ensures that the isolation layer 2 retains sufficient and uniform body material, improves the tear resistance and deformation resistance, and reduces the risk of losing insulation protection due to the failure of the isolation layer 2.

[0037] Furthermore, the matrix-distributed structural adhesive 4 layers ensure uniform distribution of curing shrinkage stress, preventing localized accumulation. Combined with a center-to-center distance of 1.2 to 3 times the pore size, this further avoids mutual interference of shrinkage stress between adjacent adhesive layers, reducing the probability of gaps appearing between the separator layer 2 and the top surface of the battery cell 1. This ensures that the separator layer 2 remains tightly bonded to the battery cell, eliminating the risk of impurities intruding through gaps.

[0038] In one embodiment, the cross-sectional shape of the through hole 21 is rectangular, circular, triangular, or oblong.

[0039] In this embodiment, the circular through hole 21 is adapted to high-precision processing equipment such as laser drilling and CNC drilling, and is especially suitable for flexible isolation layers such as PET and PP; the rectangular and waist-shaped through holes 21 are more suitable for die-cutting processes, and can be mass-produced through customized molds, which is suitable for isolation layers with thicker thickness or stronger rigidity; the triangular through hole 21 can be achieved through etching or precision die-cutting, which is suitable for scenarios with special space requirements for the corners of the hole.

[0040] This preferred embodiment provides four cross-sectional shapes: rectangle, circle, triangle, and waist. This not only solves the limitations of a single shape in terms of process, material, and space, but also enhances the reliability of bonding through the shape characteristics. At the same time, it adapts to the performance requirements of different application scenarios. Ultimately, it upgrades the through-hole design from a single function to a flexible solution that adapts to multiple scenarios and solves multiple problems, providing a wider range of adaptability for the industrialization of battery cells.

[0041] For example, see Figure 1 As shown, the cross-sectional shape of the through hole 21 is rectangular, with a length a of 5 mm and a width b of 2 mm. The center distance c between two adjacent through holes 21 is 1.4 times the width b of the through hole 21.

[0042] In one embodiment, the plurality of through holes 21 are divided into at least two groups, and each group of through holes 21 is arranged along the width direction of the shoulder of the battery cell 1, see [reference]. Figure 3 As shown, each group of through holes 21 is connected by the same structural adhesive 4.

[0043] Compared to single-group multi-hole designs, the design with at least two groups upgrades the adhesive bonding from single-area redundancy to multi-area independent redundancy, further improving sealing reliability. The adhesive layer of each group of through-holes 21 forms an independent adhesive bonding unit. If one group fails to bond due to adhesive layer aging or impurity intrusion, the adhesive layers of other groups can still maintain the basic bonding function of the corresponding area in the width direction, and the failure of one group will not cause the entire shoulder width direction of the bonding to collapse.

[0044] In this embodiment, the adhesive application is upgraded from hole-by-hole to group-by-group application, which significantly reduces the complexity of the process and is suitable for the needs of large-scale automated production. If multiple through holes in each group need to be coated with adhesive individually, precise dispensing of adhesive is required for each hole (such as positioning each hole and controlling the amount of adhesive), which is cumbersome and time-consuming. However, when each group is connected with the same structural adhesive, the adhesive can be filled into all through holes 21 in the group and the isolation layer 2 between through holes 21 at one time, which greatly shortens the adhesive application time for a single cell and is especially suitable for layout scenarios with multiple groups and multiple through holes.

[0045] In one embodiment, see Figure 1 As shown, the total projected area of ​​the plurality of through holes 21 on the top surface of the battery cell 1 is greater than or equal to a preset area threshold.

[0046] The preset area threshold essentially quantifies and guarantees the total adhesive strength of multiple through holes 21, addressing the issue of weak connection strength caused by insufficient total projected area despite numerous small holes, and ensuring that the total adhesion of the adhesive layer meets the force requirements. The pressure strip 3 needs to transmit pre-tightening force and resist the expansion force and vibration tension of the battery cell through the adhesive layer, and the adhesive layer adhesion is positively correlated with the adhesive contact area. If the total projected area of ​​multiple through holes 21 is too small, the total contact area of ​​the adhesive layer is insufficient, which can easily lead to overall peeling of the adhesive layer. Setting the preset area threshold ensures that the total projected area covers the minimum adhesive area required for the pressure strip to bear force, allowing the total adhesion of the adhesive layer to stably support the function of the pressure strip 3 and avoiding connection failure due to insufficient area.

[0047] For example, the preset area threshold is 50mm. 2 .

[0048] In one embodiment, this application also provides a battery pack, including a pressure strip 3 and a battery cell as described in any of the above embodiments, wherein the pressure strip 3 is bonded and fixed to the top surface of the battery cell 1 by the structural adhesive 4.

[0049] In one embodiment, see Figure 4 As shown, one of the bottom surface of the pressure strip 3 and the top surface of the battery cell 1 is provided with a groove 11, and the other is provided with a protrusion 31 that fits with the groove 11 with a gap.

[0050] The concave-convex gap provides a physical positioning reference for the assembly of the pressure strip 3 and the battery cell 1. During assembly, the protrusion 31 can be directly inserted into the groove 11 to form a guide positioning, eliminating the need for manual or equipment-based precise calibration of the pressure strip position, which greatly shortens the assembly time and avoids misalignment of the through hole 21 and the adhesive layer caused by the offset of the pressure strip 3.

[0051] Furthermore, the concave-convex fit optimizes the adhesive layer distribution through spatial morphology, enhancing the mechanical interlocking and anti-overflow effect of the adhesive bond. After the protrusion 31 is inserted into the groove 11, the structural adhesive 4 fills the gap between the groove 11 and the protrusion 31, while simultaneously covering the top surface of the protrusion 31 and the bottom of the groove 11. Compared to planar adhesive bonding, the adhesive layer forms a three-dimensional shape that wraps around the protrusion 31, increasing the adhesive contact area. At the same time, the interlocking between the sidewall of the protrusion 31 and the adhesive layer enhances the adhesive bonding force, reducing the risk of peeling between the adhesive layer and the contact surface. Meanwhile, the groove 11 can serve as an adhesive reservoir. Excess adhesive during application is confined within the groove 11, preventing it from spreading arbitrarily to sensitive areas such as the tabs and explosion-proof valves on the top surface of the battery cell 1. Simple planar adhesive bonding is prone to overflow due to improper adhesive control. The concave-convex fit reduces the risk of short circuits caused by overflow and ensures that all adhesive is used for bonding, improving adhesive utilization.

[0052] In one embodiment, see Figure 4 As shown, the top surface of the battery cell 1 is provided with a groove 11, and the bottom surface of the pressure strip 3 is provided with a protrusion 31 that fits with the groove 11 with a gap. The orthographic projection of the groove 11 on the top surface of the battery cell 1 covers the orthographic projection of the through hole 21 on the top surface of the battery cell 1.

[0053] In this embodiment, since the orthographic projection of the groove 11 on the top surface of the battery cell 1 covers the orthographic projection of the through hole 21 on the top surface of the battery cell 1, the adhesive can naturally flow into the groove 11 on the top surface of the battery cell 1 below while filling the through hole 21, ensuring that each groove 11 is fully filled with adhesive.

[0054] In one embodiment, the roughness of the groove wall of the groove 11 is greater than a preset roughness threshold.

[0055] When the roughness of the groove wall exceeds a preset roughness threshold, tiny uneven textures will form on the wall surface. When the adhesive fills the groove 11, these textures can be embedded, forming an interlocking structure of adhesive teeth and groove wall textures. Compared to smooth groove walls that rely solely on planar contact, the actual adhesive contact area of ​​the rough groove wall is significantly increased, and the interfacial adhesion between the adhesive layer and the groove wall is significantly improved. This prevents the adhesive layer from detaching from the groove wall due to vibration or cell expansion, and strengthens the complete connection chain of pressure strip-adhesive layer-isolation layer-cell unit.

[0056] In one embodiment, this application also provides a vehicle including the battery pack described in the above embodiments.

[0057] The vehicles mentioned can be, but are not limited to, pure electric vehicles (PEV / BEV), hybrid electric vehicles (HEV), range-extended electric vehicles (REEV), plug-in hybrid electric vehicles (PHEV), and new energy vehicles.

[0058] The above embodiments are merely preferred embodiments provided to fully illustrate the present utility model, and the protection scope of the present utility model is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present utility model are all within the protection scope of the present utility model.

Claims

1. A battery cell, characterized in that: Includes a single cell (1) and an insulating layer (2); The isolation layer (2) is applied to the top surface of the battery cell (1), and the isolation layer (2) has a plurality of through holes (21) arranged at preset intervals in the area corresponding to the shoulder of the top surface of the battery cell (1). The through holes (21) are filled with structural adhesive (4) for connection with the pressure strip (3).

2. The battery cell according to claim 1, characterized in that: The multiple through holes (21) are arranged in a matrix along the length of the shoulder of the battery cell (1), and the center distance between two adjacent through holes (21) is 1.2 to 3 times the diameter of the through hole (21).

3. The battery cell according to claim 1, characterized in that: The cross-sectional shape of the through hole (21) is rectangular, circular, triangular or waist-shaped.

4. The battery cell according to claim 1, characterized in that: The plurality of through holes (21) are divided into at least two groups, each group of through holes (21) is arranged along the width direction of the shoulder of the battery cell (1), and each group of through holes (21) is connected by the same structural adhesive (4).

5. The battery cell according to claim 1, characterized in that: The total projected area of ​​the multiple through holes (21) on the top surface of the battery cell is greater than or equal to a preset area threshold.

6. A battery pack, characterized in that: It includes a pressure strip (3) and a battery cell as described in any one of claims 1 to 5, wherein the pressure strip (3) is bonded and fixed to the top surface of the battery cell unit (1) by the structural adhesive (4).

7. The battery pack according to claim 6, characterized in that: One of the bottom surface of the pressure strip (3) and the top surface of the battery cell (1) is provided with a groove (11), and the other is provided with a protrusion (31) that fits the groove (11) with a gap.

8. The battery pack according to claim 7, characterized in that: The top surface of the battery cell (1) is provided with a groove (11), and the bottom surface of the pressure strip (3) is provided with a protrusion (31) that fits the groove (11) with a gap. The orthographic projection of the groove (11) on the top surface of the battery cell (1) covers the orthographic projection of the through hole (21) on the top surface of the battery cell (1).

9. The battery pack according to claim 7, characterized in that: The roughness of the groove wall of the groove (11) is greater than the preset roughness threshold.

10. A vehicle, characterized in that: Includes the battery pack as described in any one of claims 6 to 9.

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