Integrated flexible pressure sensing device

Abstract

The utility model provides an integrated flexible pressure sensing device. The integrated flexible pressure sensing device comprises a first insulating layer; the piezoresistive polymer film layer is located on the first insulating layer; the pair of interdigital electrode layers are positioned on the piezoresistive polymer film layer and lead out electricity outwards; the piezoelectric polymer array layer is located on each interdigital of the interdigital electrode layer, and piezoelectric polymers are printed on each interdigital, are not connected with each other and are not in contact with the piezoresistive polymer film layer; the electrode array layer is located on the piezoelectric polymer array layer, each electrode of the electrode array layer is located on the corresponding piezoelectric polymer and leads out electricity outwards, and the electrodes of the electrode array layer and the interdigital electrodes are separated by the piezoelectric polymers and are not electrically connected; and the second insulating layer is positioned on the electrode array layer.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and particularly to a pressure sensor for a lithium battery pack. Background Art

[0002] With the rapid development of the new energy vehicle industry, the capacity and cycle performance of power batteries have been continuously improved, which has brought huge challenges to safety performance. Safety is an important criterion for measuring the performance of new energy vehicles. The power battery module needs to be monitored for real-time safety status during operation, and also needs to be regularly detected in the non-operating state.

[0003] The pressure inside the PACK is often related to risk factors such as overheating and gas bulging, which is an important part of safety monitoring. Conventional shell detection is difficult to clearly reflect problems such as lithium-ion insertion phase change, lithium deposition, gas production, and thermal runaway of the battery cells inside the battery. Especially in the case of the blade battery structure that greatly improves the component integration, when the shell bulges or the external pressure is abnormal, serious failures and safety risks have already occurred inside. Therefore, it is necessary to accurately and dynamically monitor the pressure expansion of the battery cells by penetrating into the battery PACK.

[0004] The pressure detection methods mainly include capacitive, piezoresistive, and piezoelectric methods. Capacitive pressure sensors are generally used in the touch screen field, and their sensitivity, consistency, and long-term stability for pressure detection are difficult to meet the requirements. Piezoresistive sensors can reflect a clear pressure reference and have good stability, but their sensitivity to pressure changes is relatively low. Sensors made of PVDF series flexible piezoelectric materials have high sensitivity to pressure changes, but it is difficult to reflect the difference between continuous pressure and the pressure reference value. Sensitive detection of the continuous pressure level and the pressure change area distribution information inside the battery PACK is an urgent problem to be solved at present. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present utility model is to provide an integrated flexible pressure sensing device to solve the problem of sensitive detection of the continuous pressure level and the pressure change area distribution information inside the battery PACK in the prior art.

[0006] To achieve the above purpose and other related purposes, the present invention provides an integrated flexible pressure sensing device, comprising the following structure:

[0007] 1) A first insulating layer;

[0008] 2) A piezoresistive polymer film layer, located on the first insulating layer;

[0009] 3) A pair of interdigitated electrode layers, located on the piezoresistive polymer film layer, and electrically led outwards;

[0010] 4) A piezoelectric polymer array layer, which is located on each finger electrode of the interdigital electrode layer. The piezoelectric polymer is printed on each finger electrode, not connected to each other, and does not contact the piezoresistive polymer film layer;

[0011] 5) An electrode array layer, which is located on the piezoelectric polymer array layer. Each electrode of the electrode array is located on the corresponding piezoelectric polymer and leads out electricity outward. The electrodes of the electrode array layer and the interdigital electrodes are separated by the piezoelectric polymer and are not electrically connected;

[0012] 6) A second insulating layer, which is located on the electrode array layer.

[0013] Optionally, the first insulating layer and the second insulating layer are made of flexible materials, including one of PI film and PEI film, with a flame retardant performance of V0.

[0014] Optionally, the interdigital electrode is one of a silver electrode, a copper electrode, an aluminum electrode, and a nickel electrode.

[0015] Optionally, the piezoelectric polymer is one of PVDF, P(VDF-HFP), P(VDF-TrFE), P(VDF-HFP-TrFE), and PA11.

[0016] Optionally, the electrode array layer is a printed silver electrode.

[0017] An integrated flexible pressure sensing device of the present invention is externally connected to a data collector through an FPC and connected to a BMS. The resistance difference between the interdigital electrodes is used to monitor the overall pressure reference on the membrane surface; the change in the potential difference between the interdigital electrode and the electrode on each piezoelectric polymer is used to monitor the regional pressure change.

[0018] As described above, an integrated flexible pressure sensing device of the present invention has the following beneficial effects: The device has a compact structure, and the resistance difference between the interdigital electrodes is used to monitor the overall pressure reference on the membrane surface in a limited space area; the change in the potential difference between the interdigital electrode and the electrode on each piezoelectric polymer is used to monitor the distribution information of the pressure change area, with high accuracy and sensitivity. The integrated flexible pressure sensing device is a film structure, especially suitable for monitoring the internal area pressure of the blade battery structure. Description of the Drawings

[0019] Figure 1 It shows a schematic plan view of an integrated flexible pressure sensing device of the present invention.

[0020] Figure 2 It shows a schematic side view of an integrated flexible pressure sensing device of the present invention.

[0021] Figure 3It is shown as a schematic diagram of the working principle of an integrated flexible pressure sensing device.

[0022] Element label description:

[0023] 1 First insulating layer

[0024] 2 Piezoresistive polymer film layer

[0025] 3 Interdigitated electrode layer

[0026] 4 Piezoelectric polymer array

[0027] 5 Electrode array

[0028] 6 Second insulating layer Specific implementation manner

[0029] The following illustrates the implementation manner of the present utility model through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. The present utility model can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present utility model.

[0030] Refer to Figures 1 to 3 . It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present utility model in a schematic manner. The diagrams only show the components related to the present utility model, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and proportion of each component in actual implementation can be arbitrarily changed, and the layout of its components may also be more complex.

[0031] This embodiment provides a structure of an integrated flexible pressure sensing device, as Figure 1 , 2 shown:

[0032] A first insulating layer 1 is provided, and the piezoresistive polymer film layer 2 is attached to the first insulating layer 1, and the attachment method can be by coating, printing and curing or hot pressing. The first insulating layer 1 is made of a flexible material, including one of PI film and PEI film, with a flame retardancy rating of V0. The piezoresistive polymer 2 is composed of a polymer substrate and conductive fillers; the polymer substrate includes one or a mixture of polyethylene, polypropylene, polyhexafluoropropylene, vinylidene fluoride - hexafluoropropylene copolymer, vinyl chloride - vinyl acetate resin, polyethylene oxide, and phenoxy resin; the conductive filler is one of carbon black, graphene, metal carbide particles, and metal boride particles; the volume fraction of the conductive filler is lower than the percolation threshold and is 85% - 95% of the percolation threshold. An interdigital electrode layer 3 is formed on the piezoresistive polymer film layer 2, and it can be by printing silver paste or by hot pressing a metal foil and etching the circuit. The interdigital electrode 3 can be one of silver electrode, copper electrode, aluminum electrode, and nickel electrode. A piezoelectric polymer array layer 4 is screen - printed on the interdigital electrode layer 3. The piezoelectric polymer 4 is printed on each interdigital finger 3, not connected to each other, and not in contact with the piezoresistive polymer film layer 2. An electrode array layer 5 is screen - printed on the piezoelectric polymer array 4 layer and led out electrically, and the electrode array layer 5 is a printed silver electrode. Each electrode of the electrode array 5 is located on the corresponding piezoelectric polymer 4 and led out electrically, and the electrode 5 of the electrode array layer is separated from the interdigital electrode 3 by the piezoelectric polymer 4 and is not electrically connected. A second insulating layer 6 is hot - pressed and attached to the electrode array layer to obtain an integrated flexible pressure sensing device. The second insulating layer 6 is made of a flexible material, including one of PI film and PEI film, with a flame retardancy rating of V0. The electrode array layer 5 is led out electrically to the edge of the device.

[0033] The working mode of an integrated flexible pressure sensing device of the present utility model is as Figure 3 shown. The integrated flexible pressure sensing device is externally connected to a data collector through an FPC and connected to a BMS. The resistance difference between the interdigital electrodes is used to monitor the overall pressure reference on the film surface; the change in the potential difference between the interdigital electrode and the upper electrode of each piezoelectric polymer is used to monitor the regional pressure change.

[0034] In summary, for an integrated flexible pressure sensing device of the present utility model, the device structure is compact. In a limited space area, the resistance difference between the interdigital electrodes is used to monitor the overall pressure reference on the film surface; the change in the potential difference between the interdigital electrode and the upper electrode of each piezoelectric polymer is used to monitor the distribution information of the pressure change area, with high accuracy and sensitivity. The integrated flexible pressure sensing device is a film - like structure, especially suitable for monitoring the internal area pressure of an inserted blade battery structure. Therefore, the present utility model effectively overcomes the disadvantages in the prior art and has high industrial value.

[0035] The above embodiments are only illustrative of the principles and effects of the present utility model, and are not intended to limit the present utility model. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present utility model. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present utility model should still be covered by the claims of the present utility model.

Claims

1. An integrated flexible pressure sensing device, characterized in that: Contains structure: 1) The first insulating layer; 2) a piezoresistive polymer film layer, located on the first insulating layer; 3) a pair of interdigitated electrode layers, located on the piezoresistive polymer film layer, for externally drawing electrical properties; 4) a piezoelectric polymer array layer, located on each finger of the finger electrode layer, wherein the piezoelectric polymer is printed on each finger, is not connected to each other, and does not contact the piezoresistive polymer film layer; 5) an electrode array layer, located on the piezoelectric polymer array layer, wherein each electrode of the electrode array is located on a corresponding piezoelectric polymer and leads electrical properties outwardly, and the electrodes of the electrode array layer are separated from the interdigitated electrodes by the piezoelectric polymer and are not electrically connected; 6) A second insulating layer, located on the electrode array layer.

2. An integrated flexible pressure sensing device according to claim 1, characterized in that: The first insulating layer and the second insulating layer are made of flexible material, including one of PI film and PEI film, and have a flame retardant performance of V0.

3. The integrated flexible pressure sensing device according to claim 1, characterized in that: The interdigitating electrode is one of a silver electrode, a copper electrode, an aluminum electrode and a nickel electrode.

4. The integrated flexible pressure sensing device according to claim 1, characterized in that: The electrode array layer is a printed silver electrode.

5. The integrated flexible pressure sensing device according to any one of claims 1 to 4, characterized in that: The integrated flexible pressure sensing device is connected to the BMS through an FPC external data acquisition device. The resistance difference between the finger electrodes is used to monitor the overall pressure benchmark of the membrane surface; the change in potential difference between the finger electrodes and each piezoelectric polymer upper electrode is used to monitor regional pressure changes.

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