Pole piece structure, pole group of battery cell and battery cell

Abstract

The utility model provides a kind of pole piece structure, battery cell pole group and battery cell, the pole piece structure of the utility model includes pole piece matrix, and the adhesive part for sticking diaphragm is arranged on pole piece matrix, adhesive part extends along the circumferential direction of pole piece matrix and is arranged close to the circumference.The pole piece structure of the utility model can effectively bind diaphragm shrinkage without affecting battery cycle performance, to improve diaphragm heat shrinkage, and further improve the thermal safety performance of battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to an electrode structure. It also relates to a cell electrode assembly with the electrode structure, and a cell with the cell electrode assembly. Background Technology

[0002] Lithium-ion batteries have become the dominant mobile power source in the market due to their high energy density, long lifespan, and low self-discharge rate. They are widely used in daily life, such as in electric vehicles, portable computers, and digital cameras.

[0003] Currently, battery safety is receiving increasing attention. When batteries are subjected to abuse such as overcharging, overheating, or high-rate charging, their internal temperature can rise continuously, causing them to burn or even explode. There are many reasons why thermal runaway can lead to battery combustion and explosion, with one of the main causes being thermal shrinkage of the separator leading to an internal short circuit.

[0004] However, the existing method to improve the thermal shrinkage of the separator in batteries is mainly to coat the surface of the bare separator with a ceramic coating. This method has limited effect on improving thermal shrinkage, and the large amount of ceramic coating used will also increase the cost of the battery, which is not conducive to the development and design of the battery. Utility Model Content

[0005] In view of this, the present invention aims to propose an electrode structure that can improve the thermal safety performance of the battery.

[0006] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0007] An electrode structure includes an electrode substrate and an adhesive portion disposed on the electrode substrate for bonding a diaphragm, the adhesive portion extending along the periphery of the electrode substrate and arranged close to the periphery.

[0008] Furthermore, the adhesive portion includes a plurality of adhesive units evenly distributed at intervals along the periphery of the electrode substrate.

[0009] Furthermore, along the periphery of the electrode substrate, the center distance between each adhesive unit is between 1 and 10 mm.

[0010] Furthermore, each of the adhesive units is rectangular.

[0011] Furthermore, the electrode substrate is rectangular; along the length direction of the electrode substrate, the length dimension of each adhesive unit is between 2 and 8 mm, and / or, along the width direction of the electrode substrate, the width dimension of each adhesive unit is between 2 and 8 mm.

[0012] Furthermore, the distance between one side of the adhesive portion and the periphery of the electrode substrate is between 0 and 20 mm.

[0013] Furthermore, the thickness of the adhesive portion is between 30 and 100 μm.

[0014] Furthermore, the adhesive portion is made of a water-based adhesive.

[0015] Compared with the prior art, this utility model has the following advantages:

[0016] The electrode structure described in this utility model, by providing an adhesive portion on the electrode substrate, and having the adhesive portion extend along the periphery of the electrode substrate and be arranged close to the periphery, can effectively restrain the shrinkage of the separator without affecting the battery cycle performance, thereby improving the thermal shrinkage of the separator and thus enhancing the thermal safety performance of the battery.

[0017] Furthermore, since the adhesive section is mainly composed of multiple adhesive units, the amount of adhesive can be reduced while effectively bonding the diaphragm, thus achieving cost reduction. Along the periphery of the electrode substrate, the center-to-center distance between each adhesive unit is between 1 and 10 mm, which improves the rationality of the adhesive placement and helps to reduce the shrinkage of the diaphragm in the periphery of the electrode substrate. Each adhesive unit is rectangular, which facilitates consistent adhesive application and improves the convenience of the adhesive application process.

[0018] Furthermore, the electrode substrate is rectangular. Along the length of the electrode substrate, the length of each adhesive unit is between 2 and 8 mm, and along the width of the electrode substrate, the width of each adhesive unit is between 2 and 8 mm. This ensures sufficient adhesive volume and guarantees bonding strength. The distance between one side of the adhesive portion and the periphery of the electrode substrate is between 0 and 20 mm, which helps to reduce shrinkage of the separator body and thus ensures the overall thermal safety of the battery. The thickness of the adhesive portion is between 30 and 100 μm, which helps to ensure the connection strength of each adhesive point. The adhesive portion is made of a water-based adhesive, which has the advantages of mature and readily available materials and helps to control costs.

[0019] Another objective of this invention is to provide a battery cell electrode assembly, comprising the electrode structure as described above, and a separator connected to the electrode substrate via the adhesive portion, wherein the electrode substrate is a positive electrode or a negative electrode.

[0020] Meanwhile, another objective of this utility model is to provide a battery cell, including a housing and the aforementioned battery cell electrode assembly disposed in the housing.

[0021] The battery cell electrode assembly and battery cell described in this utility model have the same beneficial effects as the electrode structure described above compared with traditional technologies, and will not be described in detail here. Attached Figure Description

[0022] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0023] Figure 1 This is a top view of the electrode structure described in an embodiment of the present invention;

[0024] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0025] Figure 3 This is a front view of the electrode structure described in an embodiment of the present invention;

[0026] Figure 4 for Figure 3 Enlarged view of point B in the middle;

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Electrode substrate; 2. Adhesive unit; G1. Center distance between adhesive units; L. Length of adhesive unit; G2. Spacing between one side of the adhesive part and the periphery of the electrode substrate; D. Thickness of adhesive part. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0030] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, they are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] Furthermore, in the description of this utility model, unless otherwise explicitly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model in light of the specific circumstances.

[0032] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] Example 1

[0034] This embodiment relates to an electrode structure that, by controlling the size of the adhesive coating, effectively restricts the thermal shrinkage of the separator without deteriorating the cell's cycle performance, thereby improving the battery's thermal safety.

[0035] In terms of overall structure, such as Figures 1 to 4 As shown, the electrode structure of this embodiment includes an electrode substrate 1 and an adhesive portion disposed on the electrode substrate 1 for bonding a diaphragm. The adhesive portion extends along the periphery of the electrode substrate 1 and is arranged close to the periphery.

[0036] Specifically, in this embodiment, as an exemplary structure, such as Figure 1 As shown, the adhesive portion includes a plurality of adhesive units 2 evenly distributed at intervals along the periphery of the electrode substrate 1. The advantage of this arrangement is that it can effectively bond the diaphragm while reducing the amount of adhesive, thereby achieving cost reduction.

[0037] For specific implementation, please refer to Figure 2 As shown, in a preferred embodiment, the center distance G1 between each adhesive unit 2 is between 1 and 10 mm along the periphery of the electrode substrate 1. This improves the rationality of the adhesive placement and helps to reduce the shrinkage of the diaphragm in the periphery of the electrode substrate 1.

[0038] It is worth mentioning that, Figure 2 When G1 is specifically marked, it refers to the side edge of the same side along the periphery of the electrode substrate 1 of two adjacent adhesive units 2. The distance between the two side edges is equal to the center distance between the two adjacent adhesive units 2, which is the aforementioned center distance dimension G1.

[0039] In addition, continue to refer to Figure 1 and Figure 2 As shown, in this embodiment, as a preferred implementation, each adhesive unit 2 is rectangular. This arrangement facilitates consistent adhesive application and improves the convenience of the adhesive application process.

[0040] Furthermore, in this embodiment, as a preferred embodiment, the electrode substrate 1 is rectangular. Along the length direction of the electrode substrate 1, the length of each adhesive unit 2 is between 2 and 8 mm. Also as a preferred embodiment, along the width direction of the electrode substrate 1, the width of each adhesive unit 2 is between 2 and 8 mm, thus ensuring sufficient adhesive amount and guaranteeing bonding strength.

[0041] In specific implementation, the length of each adhesive unit 2 is set to 2mm, 4mm, 6mm or 8mm, etc. At this time, the width of each adhesive unit 2 can also be set to 2mm, 4mm, 6mm or 8mm, etc., in order to achieve a better bonding effect. When the length and width of the adhesive unit 2 are the same, the adhesive unit 2 is square.

[0042] Furthermore, in this embodiment, as a preferred implementation, the distance G2 between one side of the adhesive portion and the periphery of the electrode substrate 1 is between 0 and 20 mm, that is, the distance G2 between each adhesive unit 2 and the periphery of the electrode substrate 1 is between 0 and 20 mm. This helps to improve the shrinkage of the separator body, thereby ensuring the overall thermal safety of the battery.

[0043] Reference Figure 3 and Figure 4 As shown, in a preferred embodiment, the thickness D of the adhesive portion is between 30 and 100 μm, that is, the thickness D of each adhesive unit 2 is between 30 and 100 μm. This arrangement helps ensure the connection strength of each adhesive point.

[0044] It is worth mentioning that the specific structure and size design of the adhesive unit 2, which is not mentioned in this embodiment, can be set and adjusted according to the actual bonding requirements of the diaphragm. For example, the center distance G1 between each adhesive unit 2 can be 1mm, 5mm or 10mm.

[0045] Meanwhile, the spacing G2 between one side of each adhesive unit 2 and the periphery of the electrode substrate 1 can be 0mm, 10mm, or 20mm, and the thickness D of each adhesive unit 2 can be 30um, 60um, or 100um, etc., to achieve a better structural and dimensional design, ensure the bonding effect between the electrode substrate 1 and the diaphragm, and thus achieve a better improvement in the thermal shrinkage of the diaphragm. It should be noted that the "one side" of the adhesive unit 2 here mainly refers to the side of the adhesive unit 2 closest to the periphery of the electrode substrate 1.

[0046] Furthermore, the electrode substrate 1 in this embodiment can be a positive electrode or a negative electrode, that is, the separator can be bonded to the positive electrode or the negative electrode using the adhesive method of this embodiment to improve the thermal shrinkage of the separator.

[0047] In addition, in this embodiment, as a preferred implementation, the adhesive part is made of a water-based adhesive. It is understood that this arrangement has the advantage of using readily available and readily available materials, and it also helps control costs.

[0048] Furthermore, to illustrate the effect of the electrode structure adopted in this embodiment, the table below shows the test results of the embodiment (using the design scheme of coating the above-mentioned adhesive unit 2 on the negative electrode at a 1mm interval to bond the diaphragm) and the comparative example (the design scheme of coating the diaphragm with a ceramic coating in the prior art) during the hot box test.

[0049] Table 1 Examples

[0050]

[0051] Table 2 Comparative Examples

[0052]

[0053] Here, 12um PP (polypropylene) refers to a polypropylene separator with a thickness of 12um, MD (Machine Direction) refers to the longitudinal direction, TD (Transverse Direction) refers to the transverse direction, and BOM cost refers to the cost of raw materials.

[0054] The results of comparing Table 1 (Example) and Table 2 (Comparative Example) show that the design of coating the diaphragm with a ceramic coating can improve the thermal shrinkage problem of the diaphragm to some extent, but the improvement effect is limited, with only a 60% pass rate in the hot box test.

[0055] However, the design scheme of using adhesive unit 2 of this embodiment to bond the diaphragm by coating the negative electrode sheet at a 1mm interval can effectively improve the thermal shrinkage of the diaphragm and the safety of the hot box test, without deteriorating the cycle performance, and further reduce the BOM cost.

[0056] In this embodiment, the electrode structure provides an adhesive portion on the electrode substrate 1. The adhesive portion extends along the periphery of the electrode substrate 1 and is arranged close to the periphery. This effectively restricts the shrinkage of the separator without affecting the battery cycle performance, thereby improving the thermal shrinkage of the separator and enhancing the thermal safety performance of the battery.

[0057] Example 2

[0058] This embodiment relates to a battery cell electrode assembly, which includes the electrode structure of Embodiment 1 and a separator connected to the electrode substrate 1 via an adhesive portion, wherein the electrode substrate 1 is a positive electrode or a negative electrode. This embodiment also relates to a battery cell, including a housing and the aforementioned battery cell electrode assembly disposed within the housing.

[0059] The electrode assembly and battery cell of this embodiment, by setting the electrode structure in Embodiment 1, help to improve the thermal shrinkage of the diaphragm, thereby improving the thermal safety performance of the finished product.

[0060] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An electrode structure, characterized in that: It includes an electrode substrate and an adhesive portion disposed on the electrode substrate for bonding a diaphragm, the adhesive portion extending along the periphery of the electrode substrate and arranged close to the periphery; The adhesive portion includes a plurality of adhesive units evenly distributed at intervals along the periphery of the electrode substrate.

2. The electrode structure according to claim 1, characterized in that: Along the periphery of the electrode substrate, the center distance between each adhesive unit is between 1 and 10 mm.

3. The electrode structure according to claim 1, characterized in that: Each of the adhesive units is rectangular.

4. The electrode structure according to claim 3, characterized in that: The electrode substrate is rectangular; Along the length direction of the electrode substrate, the length of each adhesive unit is between 2 and 8 mm, and / or, along the width direction of the electrode substrate, the width of each adhesive unit is between 2 and 8 mm.

5. The electrode structure according to claim 1, characterized in that: The distance between one side of the adhesive portion and the periphery of the electrode substrate is between 0 and 20 mm.

6. The electrode structure according to claim 1, characterized in that: The thickness of the adhesive portion is between 30 and 100 μm.

7. The electrode structure according to any one of claims 1 to 6, characterized in that: The adhesive portion is made of a water-based adhesive.

8. A cell electrode assembly, characterized in that: The electrode structure includes any one of claims 1 to 7, and a separator connected to the electrode substrate via the adhesive portion, wherein the electrode substrate is a positive electrode or a negative electrode.

9. A battery cell, comprising a housing, characterized in that: It also includes the cell electrode assembly of claim 8 disposed in the housing.

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