Pressure sensing composite current collector, pole piece and battery

Abstract

The utility model discloses a pressure sensing composite current collector, a pole piece and a battery. The pressure sensing composite current collector comprises a pressure sensing layer, packaging layers and a metal layer, the pressure sensing layer comprises a pressure sensitive material layer and a lead, and the packaging layers are arranged on the two sides of the pressure sensitive material layer and wrap the pressure sensitive material layer. The pressure sensitive material layer is arranged on the packaging layer, the metal layer is arranged on one side, far away from the pressure sensitive material layer, of the packaging layer, the packaging layer is coated with the metal layer, one end of the lead is connected with the pressure sensitive material layer, and the other end of the lead penetrates through the packaging layer and the metal layer. According to the pressure sensing composite current collector, a sensing device is implanted in a lossless manner, the process complexity is reduced, the service life of a battery is prolonged, meanwhile, the charging and discharging operation states of the battery can be effectively monitored, abnormity can be effectively monitored, early warning can be performed in time, and the safety of the battery is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of battery production, in particular to a pressure sensing composite current collector, a pole piece and a battery. Background Art

[0002] With the popularity of new energy vehicles, the required battery performance requirements are getting higher and higher, and the demand for battery safety is becoming more and more stringent. The current battery management system is limited to monitoring external characteristic signals, and the internal state of the battery is a black box. Sensors are needed to monitor the inside of the battery. However, implanting sensors inside the battery will damage the battery and increase the complexity of the production process. The current conventional monitoring methods include voltage, temperature, pressure, expansion force, etc. Therefore, based on the existing battery monitoring principle, how to solve the battery damage problem caused by implanting sensors inside the battery, improve monitoring accuracy, and reduce process costs, is an urgent problem to be solved. Utility Model Content

[0003] The utility model aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one purpose of the utility model is to propose a pressure sensing composite current collector, a pole piece and a battery. The pressure sensing composite current collector realizes non-destructive implantation of sensor components, reduces process complexity, and prolongs the service life of the battery. At the same time, it can effectively monitor the battery charging and discharging operation status, effectively monitor abnormalities, and promptly warn to ensure the safety of the battery.

[0004] In one aspect of the present invention, the present invention discloses a pressure sensing composite current collector. According to an embodiment of the present invention, the pressure sensing composite current collector comprises:

[0005] A pressure sensing layer, the pressure sensing layer comprising a pressure sensitive material layer and leads;

[0006] A packaging layer, the packaging layer is disposed on both sides of the pressure sensitive material layer and covers the pressure sensitive material layer;

[0007] a metal layer, the metal layer being disposed on a side of the packaging layer away from the pressure-sensitive material layer, and the metal layer covering the packaging layer;

[0008] One end of the lead is connected to the pressure sensitive material layer, and the other end of the lead penetrates the packaging layer and the metal layer.

[0009] According to the pressure sensing composite current collector of the above embodiment of the utility model, it includes a pressure sensing layer, a packaging layer and a metal layer. The pressure sensing layer includes a pressure sensitive material layer and a lead. The packaging layer is arranged on both sides of the pressure sensitive material layer and covers the pressure sensitive material layer. The packaging layer isolates the pressure sensor layer from the external environment, thereby avoiding corrosion of the pressure sensing layer by the electrolyte and extending the service life of the composite current collector. The metal layer is arranged on the side of the packaging layer away from the pressure sensitive material layer, and the metal layer covers the packaging layer. The metal layer is used to gather current and conduct electrons to the external circuit. The current collector is one of the indispensable components in the battery. The active material is coated on the current collector to form a pole piece. During the battery charging and discharging process, the ion extraction and insertion of the positive and negative electrode materials are accompanied by the change of the volume of the material particles and the generation of stress / strain. This pressure change indirectly acts on the pressure sensitive material layer of the pressure sensing layer. The pressure sensitive material layer deforms when stimulated by external pressure, so that the pressure change is presented in the form of an electrical signal through the lead, thereby accurately monitoring the pressure change inside the battery. In particular, when the battery is in thermal runaway, the internal pressure of the battery changes greatly, and the pressure signal characteristics are very obvious, so the pressure signal changes of the pressure device in the composite current collector can be used to accurately reflect the internal conditions of the battery. As a result, the pressure sensing composite current collector realizes non-destructive implantation of sensor devices, reduces process complexity, and prolongs the service life of the battery. At the same time, it can effectively monitor the battery charging and discharging operation status, effectively monitor abnormalities, and promptly warn to ensure the safety of the battery.

[0010] In addition, the pressure sensing composite current collector according to the above embodiment of the utility model may also have the following technical features:

[0011] In some embodiments of the present invention, the pressure sensitive material layer includes a plurality of independently spaced pressure sensitive material layer units, the plurality of pressure sensitive material layer units are located in the same plane, and each of the pressure sensitive material layer units is connected to one of the lead wires, thereby improving the pressure monitoring accuracy of the composite current collector.

[0012] In some embodiments of the present invention, the shape of the pressure sensitive material layer unit is square, rectangular or ring.

[0013] In some embodiments of the present invention, the thickness of the pressure sensitive material layer is 10 um to 100 um, thereby improving the pressure monitoring accuracy of the composite current collector.

[0014] In some embodiments of the present invention, the pressure sensitive material layer includes graphene, carbon nanotubes, silver nanowires or polypyrrole.

[0015] In some embodiments of the present invention, the thickness of the packaging layer on one side of the pressure sensing layer is 5 um to 100 um, thereby improving the pressure monitoring accuracy of the composite current collector.

[0016] In some embodiments of the present invention, the thickness of the metal layer on one side of the packaging layer is 10 um to 50 um. Thus, the pressure monitoring accuracy of the composite current collector can be improved.

[0017] In some embodiments of the present invention, a tab is provided on the metal layer.

[0018] In a second aspect of the present invention, the present invention proposes a pole piece. According to an embodiment of the present invention, the pole piece includes the pressure sensing composite current collector. Thus, the pole piece has a pressure monitoring function and can accurately monitor changes in the internal pressure of the battery.

[0019] In a third aspect of the present invention, the present invention provides a battery. According to an embodiment of the present invention, the battery includes the above-mentioned pole piece. Thus, the battery has higher safety and longer service life.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 This is a schematic diagram of the structure of a pressure sensing composite current collector according to an embodiment of the utility model;

[0023] Figure 2 This is a schematic diagram of the pressure sensing layer structure of an embodiment of the utility model;

[0024] Figure 3 is a schematic diagram of the pressure sensing layer structure of another embodiment of the utility model;

[0025] Figure 4 This is a schematic diagram of the pressure sensing layer structure of another embodiment of the utility model;

[0026] Figure 5 This is a schematic diagram of the structure of a pressure sensing composite current collector according to another embodiment of the utility model;

[0027] Figure 6 This is a charge and discharge data diagram of the battery of Example 1 of the utility model;

[0028] Figure 7This is a pressure diagram collected by the pressure sensing composite current collector of Example 1 of the utility model. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0030] In one aspect of the present invention, the present invention discloses a pressure sensing composite current collector. According to an embodiment of the present invention, referring to Figure 1 The pressure sensing composite current collector includes: a pressure sensing layer 100 , a packaging layer 200 and a metal layer 300 .

[0031] According to the embodiment of the present utility model, referring to Figure 1 and Figure 2 The pressure sensing layer 100 includes a pressure sensitive material layer 110 and a lead 120. One end of the lead 120 is connected to the pressure sensitive material layer 110, and the other end of the lead 120 penetrates the encapsulation layer 200 and the metal layer 300. The current collector is one of the indispensable components of the battery. The active material is coated on the current collector to form a pole piece. During the battery charging and discharging process, the ion insertion and extraction in the positive and negative electrode materials are accompanied by the change in the volume of the material particles and the generation of stress / strain. This pressure change indirectly acts on the pressure sensitive material layer 110 of the pressure sensing layer 100. The pressure sensitive material layer 110 is deformed when stimulated by external pressure, so that the pressure change is presented in the form of an electrical signal through the lead 120, thereby accurately monitoring the pressure change inside the battery. Further, the pressure sensitive material layer 110 includes but is not limited to graphene, carbon nanotubes, silver nanowires or polypyrrole, etc., so that the external pressure change can be converted into resistance or current change based on the piezoresistive effect.

[0032] According to the embodiment of the utility model, the thickness of the pressure sensitive material layer 110 is 10um to 100um. The inventors found that the thickness of the pressure sensitive material layer 110 within the above range can reduce the impact on the overall thickness of the battery, while having good pressure sensing capability and effectively changing the external pressure into a current signal.

[0033] According to the embodiment of the present utility model, referring to Figure 3 and Figure 4The pressure-sensitive material layer 110 includes a plurality of independently spaced pressure-sensitive material layer units 111, the plurality of pressure-sensitive material layer units 111 are located in the same plane, and each pressure-sensitive material layer unit 111 is connected to a lead 120. The inventors found that by dividing the pressure-sensitive material layer 110 into a plurality of spaced pressure-sensitive material layer units 111, each pressure-sensitive material layer unit 111 is connected to a lead 120, and for different current collector regions, the pressure changes in each different region can be obtained respectively, and then each pressure change is transmitted through the lead in the form of an electrical signal. Compared with a large pressure monitoring area, monitoring the pressure changes in different small regions separately can better reflect the real-time status of the pressure changes inside the battery, and can improve the pressure monitoring accuracy of the composite current collector. Furthermore, the shape of the pressure-sensitive material layer unit 111 is square, rectangular or ring-shaped. It should be noted that the present application does not limit the size or number of the pressure-sensitive material layer unit 111, and those skilled in the art can make a choice according to actual conditions.

[0034] According to an embodiment of the utility model, the encapsulation layer 200 is disposed on both sides of the pressure sensitive material layer 100 and covers the pressure sensitive material layer 100. The encapsulation layer 200 isolates the pressure sensor layer 100 from the external environment, thereby preventing the electrolyte from corroding the pressure sensing layer 100 and extending the service life of the composite current collector. It should be noted that the encapsulation layer 200 can be prepared using a material with good corrosion resistance and insulation properties, and those skilled in the art can select the specific encapsulation layer material according to actual conditions.

[0035] According to an embodiment of the utility model, the thickness of the packaging layer 200 on one side of the pressure sensing layer 100 is 5um to 100um. The inventors found that within the above range of the thickness of the packaging layer 200 on one side of the pressure sensing layer 100, the pressure sensing layer 100 can be effectively prevented from being corroded by the electrolyte, and the influence of the packaging layer 200 on the pressure sensing can be reduced, thereby improving the pressure monitoring accuracy of the composite current collector.

[0036] According to an embodiment of the utility model, the metal layer 300 is disposed on a side of the packaging layer 200 away from the pressure-sensitive material layer 110, and the metal layer 300 covers the packaging layer 200. The metal layer 300 is used to gather current and conduct electrons to the external circuit. It can be understood by those skilled in the art that the metal layer 300 mainly plays a conductive role. Those skilled in the art can select the specific material of the metal layer 300 according to the specific purpose of the current collector for preparing the positive electrode or the negative electrode. For example, the metal layer 300 includes but is not limited to aluminum or copper.

[0037] According to an embodiment of the utility model, the thickness of the metal layer 300 on one side of the encapsulation layer 200 is 10um to 50um. The inventors have found that when the thickness of the metal layer 300 on one side of the encapsulation layer 200 is within the above range, it can effectively conduct electricity and reduce the influence of the metal layer 300 on pressure sensing, thereby improving the pressure monitoring accuracy of the composite current collector.

[0038] According to an embodiment of the present invention, referring to Figure 5 , a pole ear 310 is provided on the metal layer 300 for collecting electrons and conducting electricity. It can be understood by those skilled in the art that the lead 120 is led out from the pressure sensing composite current collector for conducting electrical signals. In order to ensure the sealing of the lead 120, the packaging layer 200 of the present application includes a lead packaging layer 210, which matches the size of the lead and is used to package the lead 120.

[0039] Therefore, the pressure sensing composite current collector realizes non-destructive implantation of sensor devices, reduces process complexity, and prolongs the service life of the battery. At the same time, it can effectively monitor the battery charging and discharging operation status, effectively monitor abnormalities, and provide timely warnings to ensure the safety of the battery.

[0040] In the second aspect of the present invention, the present invention proposes a pole piece. According to an embodiment of the present invention, the pole piece includes the above-mentioned pressure sensing composite current collector. As a result, the pole piece has a pressure monitoring function and can accurately monitor the changes in the internal pressure of the battery. It should be noted that the features and advantages described above for the pressure sensing composite current collector are also applicable to the pole piece and will not be repeated here.

[0041] In the third aspect of the utility model, the utility model provides a battery. According to an embodiment of the utility model, the battery includes the above-mentioned pole piece. As a result, the battery has high safety and long service life. It should be noted that the features and advantages described above for the pole piece are also applicable to the battery, and will not be repeated here.

[0042] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0043] Example 1

[0044] (1) The pressure sensing composite current collector of the present application is adopted, wherein the thickness of the pressure sensitive material layer is 15 um, the material of the pressure sensitive material layer is carbon nanotubes, the thickness of the single-sided packaging layer is 20 um, and the thickness of the single-sided metal layer is 10 um. Specifically, the metal layer of the current collector for the positive electrode plate is aluminum, and the metal layer of the current collector for the negative electrode plate is copper.

[0045] (2) Preparation of positive electrode sheet: Mix the positive electrode active material NMC811 with Super P and PVDF to form a uniform slurry. Evenly coat the mixed slurry on the aluminum foil or aluminum-plated pressure sensor current collector to form a coating of 20-30 microns thick. Place the coated electrode sheet in a constant temperature box for drying, and then firmly press the positive electrode material and the current collector substrate by rolling.

[0046] (3) Preparation of negative electrode sheet: Mix graphite with Super P and CMC binder to form a uniform slurry. Evenly coat the mixed slurry on the aluminum copper foil or copper-plated pressure sensor current collector to form a coating of 20-30 microns thick. Place the coated electrode sheet in a constant temperature box for drying, and then firmly press the negative electrode material and the current collector substrate by roller pressing.

[0047] (4) Preparation of batteries: Assemble soft-pack batteries using a Z-shaped stacking process; stack the negative electrode sheet, separator, positive electrode sheet, separator, and negative electrode sheet in the order of stacking, and weld the tabs after stacking using ultrasonic welding and other equipment to obtain a battery cell. Wrap with aluminum-plastic film to obtain a dry battery cell. Place in an oven to remove moisture, then inject liquid to form a battery cell for subsequent testing.

[0048] The pressure sensor is calibrated using a high-precision pressure device, the charge and discharge are monitored using a charger and discharge machine, and the pressure is monitored using a PCB board.

[0049] The data obtained by monitoring the pressure of the PCB board is as follows Figure 6 As shown, from Figure 6 It can be seen that during the charge and discharge cycle, the upper and lower limits of the battery voltage remain between 2.8-4.2V, and the curve is normal. It can be seen that the non-destructive implantation of the distributed pressure sensor current collector in this application has no effect on the charge and discharge cycle of the battery. Figure 7 It can be seen that the pressure curve changes normally, corresponding to the force change trend of the battery charging and discharging, which means that the pressure sensing material is not corroded by the electrolyte and can monitor the battery pressure distribution inside the battery without damage.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0051] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A pressure sensing composite current collector, characterized in that: include: A pressure sensing layer, the pressure sensing layer comprising a pressure sensitive material layer and leads; A packaging layer, the packaging layer is disposed on both sides of the pressure sensitive material layer and covers the pressure sensitive material layer; a metal layer, the metal layer being disposed on a side of the packaging layer away from the pressure-sensitive material layer, and the metal layer covering the packaging layer; One end of the lead is connected to the pressure sensitive material layer, and the other end of the lead penetrates the packaging layer and the metal layer.

2. The pressure sensing composite current collector according to claim 1, characterized in that: The pressure-sensitive material layer includes a plurality of pressure-sensitive material layer units that are independently arranged at intervals, the plurality of pressure-sensitive material layer units are located in the same plane, and each of the pressure-sensitive material layer units is connected to one of the lead wires.

3. The pressure sensing composite current collector according to claim 2, characterized in that: The shape of the pressure sensitive material layer unit is square, rectangular or ring.

4. The pressure sensing composite current collector according to claim 1 or 2, characterized in that: The thickness of the pressure sensitive material layer is 10 um to 100 um.

5. The pressure sensing composite current collector according to claim 1 or 2, characterized in that: The pressure sensitive material layer includes graphene, carbon nanotubes, silver nanowires or polypyrrole.

6. The pressure sensing composite current collector according to claim 1 or 2, characterized in that: The thickness of the packaging layer on one side of the pressure sensing layer is 5um to 100um.

7. The pressure sensing composite current collector according to claim 1 or 2, characterized in that: The thickness of the metal layer on one side of the packaging layer is 10um to 50um.

8. The pressure sensing composite current collector according to claim 1 or 2, characterized in that: The metal layer is provided with a pole ear.

9. A pole piece, characterized in that: The pressure sensing composite current collector comprises any one of claims 1 to 8.

10. A battery, characterized in that: Including the pole piece as claimed in claim 9.

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