Battery cell and electronic equipment

Abstract

The embodiment of the invention provides a battery cell and electronic equipment, and relates to the technical field of batteries, and the battery cell comprises: a shell in which an accommodating cavity is formed; the naked battery core is arranged in the accommodating cavity and comprises positive plates, negative plates, isolating membranes and piezoelectric sensors, the positive plates and the negative plates are alternately arranged in the thickness direction, the isolating membranes are arranged between the positive plates and the negative plates, the piezoelectric sensors are connected in the naked battery core, and the piezoelectric sensors are arranged in the naked battery core. And the piezoelectric sensor is connected to the positive plate or the negative plate, and is used for receiving a pressure signal from the positive plate or the negative plate and converting the pressure signal into an electric signal. Compared with a traditional method, the battery cell provided by the embodiment of the invention can obtain a more stable and accurate pressure signal, so that a more reliable basis is provided for effective management of the battery.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a battery cell and an electronic device. Background Art

[0002] With the development of battery technology, various types of batteries are widely used in various electronic devices. However, as the use time of electronic devices increases, the internal batteries will swell to varying degrees, affecting the performance of the battery. Severe battery swelling can also cause battery failure and even the risk of explosion.

[0003] In order to ensure the reliability and safety of the battery, it is necessary to identify and monitor the battery expansion to provide a basis for effective battery management. However, in related technologies, the monitoring method of battery expansion is prone to misjudgment, resulting in low reliability of the monitoring results. Summary of the invention

[0004] The present application aims to provide a battery cell and an electronic device to solve the problem of low reliability of current monitoring results of battery expansion.

[0005] In order to solve the above technical problems, this application is implemented as follows:

[0006] In a first aspect, the present application discloses a battery cell, comprising:

[0007] A housing having a receiving cavity disposed therein;

[0008] A bare battery cell is arranged in the accommodating cavity, and includes a positive electrode sheet, a negative electrode sheet, an isolation film, and a piezoelectric sensor, wherein the positive electrode sheet and the negative electrode sheet are alternately arranged along the thickness direction, the isolation film is arranged between the positive electrode sheet and the negative electrode sheet, the piezoelectric sensor is connected to the inside of the bare battery cell and connected to the positive electrode sheet or the negative electrode sheet, and the piezoelectric sensor is used to receive a pressure signal from the positive electrode sheet or the negative electrode sheet and convert the pressure signal into an electrical signal.

[0009] In a second aspect, the present application also discloses an electronic device, comprising the battery cell as described above.

[0010] In the battery cell of the embodiment of the present application, the piezoelectric sensor is arranged inside the bare battery cell and connected to the positive electrode sheet or the negative electrode sheet. During the use of the battery, lithium ions are intercalated and deintercalated back and forth between the positive and negative electrodes and side reactions occur to produce byproducts, the positive and negative electrodes will expand, and adjacent electrodes will be squeezed against each other and form a pressure signal. The embodiment of the present application can accurately detect the squeezing force generated by the expansion of adjacent electrodes by placing a piezoelectric sensor on the electrode sheet inside the battery. Compared with the traditional method, the battery cell provided by the embodiment of the present application can obtain a more stable and accurate pressure signal, thereby providing a more reliable basis for the effective management of the battery.

[0011] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0013] Figure 1 It is a schematic diagram of the bare battery cell structure in the prior art;

[0014] Figure 2 It is one of the schematic diagrams of positive electrode glue sticking in the prior art;

[0015] Figure 3 This is the second schematic diagram of positive electrode glue sticking in the prior art;

[0016] Figure 4 It is one of the schematic diagrams of negative electrode glue sticking in the prior art;

[0017] Figure 5 This is the second schematic diagram of negative electrode glue sticking in the prior art;

[0018] Figure 6 This is a schematic diagram of a bare cell structure in one embodiment of the present application;

[0019] Figure 7 This is a schematic diagram of the structure of a piezoelectric sensor in one embodiment of the present application;

[0020] Figure 8 This is a schematic diagram of the structure of the negative electrode sheet in one embodiment of the present application;

[0021] Fig. 9 is a schematic diagram of the structure of a piezoelectric sensor in another embodiment of the present application;

[0022] Fig.10 This is a schematic diagram of the structure of the negative electrode sheet in another embodiment of the present application;

[0023] Fig.11This is a schematic diagram of the structure of the positive electrode sheet in another embodiment of the present application;

[0024] Fig.12 It is a schematic diagram of the battery cell structure in one embodiment of the present application.

[0025] Figure numerals: 100 - bare cell, 10 - positive electrode sheet, 11 - positive electrode ear, 12 - positive electrode ear protective glue, 13 - lithium plating protective glue, 14 - tail protective glue, 20 - negative electrode sheet, 21 - negative electrode ear, 22 - negative electrode ear protective glue, 23 - negative electrode protective glue, 30 - isolation membrane, 40 - piezoelectric sensor, 41 - piezoelectric film, 42 - connector, 421 - conductive connector, 422 - insulating connector, 50 - signal transmission component, 200 - shell, 201 - accommodating cavity. DETAILED DESCRIPTION

[0026] The embodiments of the present application will be 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 application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0027] The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0028] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0029] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] During the use of electronic devices, as the battery is charged and discharged, lithium ions are intercalated and deintercalated between the positive and negative electrodes, and side reactions occur to produce byproducts, causing the electrode to expand to a certain extent. As the use time of electronic devices increases, the degree of battery expansion of electronic devices will also increase. Severe expansion will have an adverse effect on the reliability of the battery cover and the safety of the battery. Therefore, it is necessary to identify and monitor these over-expanded batteries to provide an accurate basis for the subsequent effective management of the battery.

[0031] Common ways to monitor battery expansion include: an external fuel gauge, which predicts the battery capacity by inserting a capacity curve, and then calibrates the battery expansion ratio and lithium plating degree according to the remaining capacity of the battery. However, this method is inaccurate. Most of the time, even if the battery capacity decays a lot, the battery has not plated lithium, which may lead to misjudgment; an external sensor, which places a pressure sensor between the built-in battery and the back cover of the electronic device. When the battery expands to a certain extent, the sensor signal will change, and the expansion and lithium plating degree will be calibrated according to the size of the signal. The disadvantage of this method is that it will take up battery space, and the sensor is placed between the battery and the back cover of the electronic device, which is easily affected by external squeezing force and causes misjudgment, and it is not easy to promote.

[0032] Based on the above reasons, the present application provides a battery cell, which has a bare battery cell inside, and the bare battery cell has a built-in piezoelectric sensor. As mentioned above, during the expansion process of the electrode inside the bare battery cell, adjacent electrode stacks will be squeezed against each other to form a pressure signal. By placing a piezoelectric sensor inside the bare battery cell and transmitting the electrical signal of the piezoelectric sensor to the outside of the electronic device through a designed circuit, the size of the pressure signal can be monitored and the size of the electrode and battery expansion can be calibrated, thereby achieving the purpose of constantly monitoring the expansion state of the electrode.

[0033] The battery cell provided in the embodiment of the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0034] The battery cell disclosed in the embodiment of the present application is as follows: Fig.12As shown, it may specifically include: a shell 200 and a bare cell 100, wherein a housing cavity 201 is provided in the shell 200, and the bare cell 100 is provided in the housing cavity 201. After the bare cell 100 is installed in the shell 200, it is necessary to perform operations such as liquid injection on the bare cell 100 to achieve electrochemical performance to provide power for the electronic device, and the shell 200, as a physical barrier for the cell, can effectively protect the bare cell 100 inside from physical damage caused by external forces such as external squeezing and impact, and ensure that the cell can operate stably in a complex environment; in addition, the shell 200 can also effectively prevent the infiltration of external substances such as moisture and oxygen, and can also prevent the leakage of gas and electrolyte inside the cell. This sealing performance is crucial for maintaining the electrochemical environment inside the cell. The bare cell 100 can be a wound cell or a laminated cell. The embodiment of the present application takes the wound bare cell 100 as an example for explanation, and the laminated cell can be implemented with reference. In practical applications, technicians can make choices based on actual needs, and this application does not make any specific limitations on this.

[0035] Specifically, Figure 6 As shown, the bare battery cell 100 includes a positive electrode sheet 10, a negative electrode sheet 20, an isolation film 30, and a piezoelectric sensor 40, wherein the positive electrode sheet 10 and the negative electrode sheet 20 are alternately arranged in the thickness direction, the isolation film 30 is arranged between the positive electrode sheet 10 and the negative electrode sheet 20, and the piezoelectric sensor 40 is connected to the inside of the bare battery cell 100 and is connected to the positive electrode sheet 10 or the negative electrode sheet 20. When the inside of the battery cell expands, the piezoelectric sensor 40 will be squeezed. The piezoelectric sensor 40 is used to receive the pressure signal from the positive electrode sheet 10 or the negative electrode sheet 20 and convert the pressure signal into an electrical signal.

[0036] In the embodiment of the present application, by connecting the piezoelectric sensor 40 inside the bare battery cell 100, the expansion and compression of the electrode piece forms a pressure signal. After receiving the pressure signal, the piezoelectric sensor 40 can convert it into an electrical signal, and then transmit the electrical signal to the entire electronic device through the design of the circuit, so as to more directly characterize the expansion of the battery. At the same time, the shell 200 has a buffering effect on the external force that the battery cell may be subjected to, thereby preventing external force from squeezing the back cover of the electronic device or the battery cell shell 200 to interfere with the sensor.

[0037] It should be noted that the bare cell 100 is disposed in the shell 200 and has an outer surface opposite to the inner wall of the shell 200. After the wound cell is wound, its outer surface may be formed by one side of the positive electrode sheet 10 or the negative electrode sheet 20. The piezoelectric sensor 40 described in the embodiment of the present application is connected to the inside of the bare cell 100, which means that the piezoelectric sensor 40 is connected to other positions except the positive electrode sheet 10 or the negative electrode sheet 20 used to form the outer surface. It can be understood that since the bare cell 100 is formed by winding, except for one side of the positive electrode sheet 10 or the negative electrode sheet 20 forming the above outer surface, the remaining surfaces of the positive electrode sheet 10 or the negative electrode sheet 20 can be used to connect the piezoelectric sensor 40.

[0038] It should be noted that there is another connection method of the piezoelectric sensor 40 in the related art, that is, the piezoelectric sensor 40 is connected to the outer surface of the bare cell 100. In this method, after the piezoelectric sensor 40 is connected to the bare cell 100, it is located between the inner wall of the shell 200 and the outer surface of the bare cell 100. The cell provided in the embodiment of the present application has higher accuracy than the above method of connecting the piezoelectric sensor 40 to the outer surface of the bare cell 100.

[0039] Specifically, since the bare cell 100 usually includes a plurality of layers of positive and negative electrodes 10 and 20, and each layer of the electrodes may expand to varying degrees, when the electrodes inside the bare cell 100 expand and deform along the thickness direction, an extrusion force will be generated on the adjacent isolation film 30, and the isolation film 30 will be deformed. The deformation of the isolation film 30 will disperse the extrusion force from the electrodes, resulting in a reduction in the extrusion force ultimately transmitted to the outer surface of the bare cell 100, affecting the pressure signal received by the piezoelectric sensor 40, resulting in a decrease in the accuracy of the monitoring results. In the embodiment of the present application, the piezoelectric sensor 40 is connected inside the bare cell 100 to avoid the extrusion force generated by the expansion of the electrodes being dispersed after passing through the multi-layer isolation film 30, thereby improving the pressure signal received by the piezoelectric sensor 40 and improving the accuracy of the monitoring results.

[0040] Optionally, the piezoelectric sensor 40 includes a piezoelectric film 41 and a connector 42 connected to one side of the piezoelectric film 41. The piezoelectric film 41 is connected to the positive electrode 10 or the negative electrode 20 through the connector 42. The piezoelectric film 41 is used to receive a pressure signal from the positive electrode 10 or the negative electrode 20 and convert the pressure signal into an electrical signal.

[0041] Specifically, the piezoelectric film 41 is a special piezoelectric material. When an external mechanical stress acts on the material, it will cause the charge distribution inside the material to change in proportion to the stress, thereby generating a voltage difference. That is, the piezoelectric film 41 can convert the pressure signal into an electrical signal after receiving the squeezing force from the outside. It should be noted that as electronic equipment technology matures, especially mobile electronic equipment, it is also in a trend of miniaturization for the purpose of portability, which has certain requirements on the size of the battery. The increase in battery size is not conducive to improving the portability of electronic equipment. The piezoelectric film 41 has the characteristics of being thin, light, and flexible, which makes the piezoelectric sensor 40 made of the piezoelectric film 41 have little effect on the size of the battery. Under a specific design method, while the piezoelectric sensor 40 is set in the battery cell, the size of the original battery cell can be maintained, so that it can be easily applied to various electronic devices.

[0042] Since the piezoelectric film 41 itself cannot be connected to the positive electrode 10 or the negative electrode 20, there may be a loose connection between the piezoelectric film 41 and the positive electrode 10 or the negative electrode 20, resulting in the pressure signal generated by the expansion of the positive electrode 10 or the negative electrode 20 cannot be accurately transmitted to the piezoelectric film 41. In the embodiment of the present application, a connector 42 is provided on one side of the piezoelectric film 41. The connector 42 can be connected to the piezoelectric film 41 while also being connected to the positive electrode 10 or the negative electrode 20 to ensure that the pressure signal from the positive electrode 10 or the negative electrode 20 can be accurately transmitted to the piezoelectric film 41, thereby ensuring the accuracy of the piezoelectric film 41's monitoring results of the battery cell expansion.

[0043] Reference Figure 7 , Fig. 9 , which is a schematic diagram of the structure of two piezoelectric sensors 40 provided in the embodiment of the present application, the connectors 42 in the two piezoelectric sensors 40 are of different types, such as Figure 7 As shown, the connecting member 42 can be a conductive adhesive. Figure 8 As shown, the connector 42 is an adhesive. The present application does not specifically limit the type of the connector 42 , and any connector that can achieve connection between the piezoelectric film 41 and the positive electrode sheet 10 or the negative electrode sheet 20 is sufficient.

[0044] Optionally, a positive electrode tab 11 is provided on the positive electrode sheet 10 , and the piezoelectric sensor 40 is connected to the negative electrode sheet 20 and is opposite to the positive electrode tab 11 along the thickness direction.

[0045] like Figure 6 , Figure 8 As shown, it is a schematic diagram of the negative electrode sheet 20 before winding. Figure 8In the figure, the piezoelectric sensor 40 is connected to the negative electrode sheet 20. In actual applications, the position of the piezoelectric sensor 40 in the length direction of the negative electrode sheet 20 is also related to the size of the bare cell 100 and the position of the positive electrode ear 11. Preferably, after the bare cell 100 is wound, the piezoelectric sensor 40 and the positive electrode ear 11 are opposite to each other along the thickness direction of the bare cell 100. In the embodiment of the present application, the thickness direction of the bare cell 100 is substantially the same as the thickness direction of the electrode sheet. Furthermore, the electrode sheet and the isolation film 30 before winding also have a length direction and a width direction. The electrode sheet and the isolation film 30 are wound along the length direction. After the winding is completed, the original width direction of the electrode sheet forms the axial direction of the bare cell 100. The thickness direction of the bare cell 100 refers to the direction perpendicular to the axial direction. When the cross-section of the bare cell 100 is circular, the thickness direction of the bare cell 100 can be understood as its radial direction.

[0046] It should be noted that if Figure 1 As shown, it is a schematic diagram of the structure of a bare battery cell 100 in the prior art. The positive electrode sheet 10, the negative electrode sheet 20, and the isolation film 30 are stacked in a winding manner. Inside the bare battery cell 100, the positive electrode sheet 10 and the negative electrode sheet 20 need to be affixed with a thin film protective tape at the corresponding positions for the purpose of insulation or to prevent lithium ion penetration. The tape material is generally polyimide or PET, and the thickness is generally 10 to 20 um.

[0047] like Figures 2 to 5 As shown, schematic diagrams of double-sided adhesive bonding of the positive electrode sheet 10 and the negative electrode sheet 20 in the prior art are shown. Figure 2 , Figure 3 As shown, there are 6 layers of glue on both sides of the positive electrode sheet 10, 3 layers of glue on each side, namely: positive electrode ear protection glue 12, which is pasted on the positive electrode ear 11 welding area, and its main function is to protect the positive electrode ear 11 welding burr from piercing the isolation film 30; lithium deposition protection glue 13, which is pasted on the area corresponding to the negative electrode ear 21 welding during winding, and its main function is to prevent the lithium ions in this area from flowing from the positive electrode to the negative electrode; tail protection glue 14, which is pasted on the area corresponding to the tail of the negative electrode sheet 20 during winding, and its main function is to prevent the burr at the junction of the positive electrode sheet 10 from piercing the isolation film 30. Figure 4 , Figure 5 As shown, the negative electrode sheet 20 is affixed with 4 layers of glue on both sides, with 2 layers of glue on each side, namely: the negative electrode ear protection glue 22, which is affixed to the welding area of ​​the negative electrode ear 21, and its main function is to protect the burrs of the welding of the negative electrode ear 21 from piercing the isolation film 30; the negative electrode protection glue 23, which is affixed to the corresponding area of ​​the positive electrode ear 11 during winding, and its main function is to provide secondary protection for the welding burrs of the positive electrode ear 11.

[0048] According to the above structure of the bare battery cell 100 in the prior art, in the negative electrode sheet 20, the position opposite to the positive electrode ear 11 along the thickness direction is the negative electrode protective glue 23, and the present application connects the piezoelectric sensor 40 to the negative electrode sheet 20 and sets it at a position opposite to the positive electrode ear 11, which can replace the negative electrode protective glue 23 attached to one of the two sides of the negative electrode sheet 20 of the original bare battery cell 100. In the case of using the piezoelectric sensor 40 to replace the negative electrode protective glue 23, the piezoelectric sensor 40 not only undertakes the task of converting the pressure signal into an electrical signal, but also takes into account the task of the negative electrode protective glue 23 on the original negative electrode sheet 20, and provides secondary protection for the welding burrs of the positive electrode ear 11. Since the negative electrode protective glue 23 will have a certain thickness, such a setting can save space for the negative electrode protective glue 23, avoid the increase in the size of the battery cell due to the provision of the piezoelectric sensor 40 in the battery cell, and avoid the reduction in the battery cell capacity due to the provision of the piezoelectric sensor 40.

[0049] In addition, since the expansion of the negative electrode 20 is dominant during the battery cycle, accounting for about 80% of the total expansion of the battery, connecting the piezoelectric film 41 to the negative electrode 20 can more sensitively monitor the expansion of the electrode. Since the potential of the negative electrode 20 is relatively low, the oxidation effect on the piezoelectric film 41 is small, and the lifespan is more guaranteed.

[0050] In one embodiment of the present application, a negative electrode ear 21 is provided on the negative electrode sheet 20, and the connector 42 is a conductive connector 421, which is electrically connected to the negative electrode sheet 20. The electrical signal of the piezoelectric film 41 is transmitted to the negative electrode ear 21 through the conductive connector 421 and the negative electrode sheet 20, so as to transmit the electrical signal to the outside of the battery cell.

[0051] like Figure 7 As shown, the connector 42 is a conductive connector 421. When the piezoelectric film 41 is connected to the negative electrode sheet 20 through the conductive connector 421, since the conductive connector 421 and the negative electrode sheet 20 are both excellent conductors, the electrical signal generated by the piezoelectric film 41 can be transmitted to the negative electrode sheet 20 through the conductive connector 421, and then the signal is transmitted to the negative electrode ear 21 through the negative electrode sheet 20. In practical applications, since the negative electrode ear 21 is exposed to the shell 200 of the battery cell, and the portion of the negative electrode ear 21 exposed to the shell 200 is usually welded with a protective plate, such as Figure 8 As shown, a circuit can be added to the protection board, so that the positive signal of the pressure-sensitive film can be transmitted through the negative electrode ear 21, and then the negative signal is grounded through the metal frame of the electronic device shell to produce a negative signal. The positive and negative signals form a loop and are transmitted to the entire electronic device, so that the expansion level of the battery can be judged by the difference in signal size in different time periods. This method does not require the setting of a signal transmission component 50 to realize the transmission of electrical signals, and is simpler to implement.

[0052] It should be noted that the magnitude of the pressure can be calibrated by the magnitude of the positive and negative signals, and the degree of battery expansion can be determined by the difference in the magnitude of the positive and negative signals in different time periods.

[0053] Optionally, the conductive connecting member 421 includes at least one of a graphene-based adhesive and an aluminum layer conductive adhesive.

[0054] In practical applications, since electrolyte is injected into the battery cell, the conductive connector 421 needs to have good chemical stability while achieving the conductive function between the piezoelectric film 41 and the electrode to prevent failure due to corrosion by the battery cell electrolyte.

[0055] The above conductive connector 421 illustrated in the embodiment of the present application not only has good conductivity, but also exhibits excellent chemical corrosion resistance, can remain stable in a variety of harsh environments, and is not or less corroded by chemical substances, thereby ensuring reliability in use. The embodiment of the present application does not specifically limit the type of the conductive connector 421. In actual applications, technicians can also choose other materials with the same or similar properties.

[0056] In another embodiment of the present application, Fig. 9 As shown, the connector 42 is an insulating connector 422. Fig.10 , Fig.11 As shown, the battery cell further includes a signal transmission component 50 , which is connected to the piezoelectric film 41 and at least partially exposed outside the housing 200 .

[0057] Specifically, the insulating connector 422 is not conductive. When the piezoelectric film 41 is connected to the electrode via the insulating connector 422, the electrical signal transmission function between the piezoelectric film 41 and the electrode cannot be provided. Therefore, a signal transmission component 50 may be connected to the signal terminal of the piezoelectric film 41, and the electrical signal of the piezoelectric film 41 is transmitted to the outside of the shell 200 via the signal transmission component 50. Furthermore, a circuit may be designed outside the battery cell to realize the transmission of electrical signals between the battery cell and the electronic device.

[0058] In the embodiment of the present application, the signal connector 42 is a copper wire with a diameter of 5 to 10 um, and the surface of the copper wire is insulated. There are two copper wires, which are respectively connected to the positive and negative signal terminals of the piezoelectric film 41, and pass through the shell 200 to be exposed to the shell 200. One end of the copper wire is connected to the signal terminal of the piezoelectric film 41, and the other end is welded to the external protection board of the battery, or directly connected to the motherboard of the electronic device. During the use of the battery, a certain extrusion force is generated between the two adjacent laminated pole pieces, and the extrusion force is transmitted to the piezoelectric film 41. The piezoelectric film 41 generates an electrical signal and transmits it back to the whole machine, so as to judge the size of the battery expansion by the size of the electrical signal converted in different time periods. In this way, the piezoelectric film 41 is set on the pole piece, and the extrusion force generated by the expansion of the pole pieces between the adjacent laminated pole pieces is monitored. Compared with the traditional method of placing the piezoelectric film 41 on the outer surface of the battery, a more stable and accurate signal can be obtained.

[0059] Optionally, a positive electrode tab 11 is provided on the positive electrode sheet 10, such as Fig.10 As shown, the piezoelectric sensor 40 is connected to the negative electrode sheet 20 and is opposite to the positive electrode ear 11 along the thickness direction. It should be noted that, as mentioned above, when the piezoelectric sensor 40 is connected to the negative electrode sheet 20 and is arranged opposite to the positive electrode ear 11 along the thickness direction, it can replace the negative electrode protective glue 23 attached to one of the two sides of the negative electrode sheet 20 of the original bare battery cell 100. The piezoelectric sensor 40 not only undertakes the task of converting the pressure signal into an electrical signal, but also takes into account the task of the negative electrode protective glue 23 on the original negative electrode sheet 20, and provides secondary protection for the welding burrs of the positive electrode ear 11. Such a setting can save space for the negative electrode protective glue 23 and avoid the increase in the size of the battery cell due to the piezoelectric sensor 40 being arranged in the battery cell.

[0060] Optionally, a negative electrode tab 21 is provided on the negative electrode sheet 20, such as Fig.11 As shown, the piezoelectric sensor 40 is connected to the positive electrode sheet 10 and is opposite to the negative electrode tab 21 along the thickness direction.

[0061] According to the above structure of the bare battery cell 100 in the prior art, in the positive electrode sheet 10, the position opposite to the negative electrode ear 21 along the thickness direction is the lithium deposition protective glue 13, and the present application connects the piezoelectric sensor 40 to the positive electrode sheet 10 and sets it at a position opposite to the positive electrode ear 11, which can replace the lithium deposition protective glue 13 attached to one of the two sides of the positive electrode sheet 10 of the original bare battery cell 100. When the piezoelectric sensor 40 is used to replace the lithium deposition protective glue 13, the piezoelectric sensor 40 not only undertakes the task of converting the pressure signal into an electrical signal, but also takes into account the task of the lithium deposition protective glue 13 on the original positive electrode sheet 10, thereby preventing lithium ions in this area from flowing from the positive electrode to the negative electrode. Similarly, such a setting can also save space for the positive electrode protective glue and avoid the increase in the size of the battery cell due to the provision of the piezoelectric sensor 40 in the battery cell.

[0062] Optionally, the piezoelectric film 41 includes at least one of a silicon dioxide piezoelectric film, a carbon fiber piezoelectric film, and a semiconductor piezoelectric film.

[0063] Among them, the silicon dioxide piezoelectric film 41 has good stability and corrosion resistance, can maintain good stability inside the battery cell, and ensure monitoring performance; the carbon fiber piezoelectric film 41 has good chemical stability, and can maintain stable performance in a variety of chemical environments; the semiconductor piezoelectric film 41 has high sensitivity and a wide response range, and can accurately detect weak mechanical vibrations or pressure changes, so that the monitoring results can be more accurate.

[0064] In summary, the battery cell provided by the embodiment of the present application has at least the following advantages:

[0065] In the battery cell of the embodiment of the present application, the piezoelectric sensor is arranged inside the bare battery cell and connected to the positive electrode sheet or the negative electrode sheet. During the use of the battery, lithium ions are intercalated and deintercalated back and forth between the positive and negative electrodes and side reactions occur to produce byproducts, the positive and negative electrodes will expand, and adjacent electrodes will be squeezed against each other and form a pressure signal. The embodiment of the present application can accurately detect the squeezing force generated by the expansion of adjacent electrodes by placing a piezoelectric sensor on the electrode sheet inside the battery. Compared with the traditional method, the battery cell provided by the embodiment of the present application can obtain a more stable and accurate pressure signal, thereby providing a more reliable basis for the effective management of the battery.

[0066] The present application also discloses an electronic device, comprising the battery cell as described above.

[0067] It should be noted that the electronic device provided in the embodiment of the present application has the same or similar beneficial effects as the battery cell described above, which will not be repeated here. In addition, the electronic device described in the embodiment of the present application may include a mobile phone, a tablet computer, a laptop computer, a wearable device, etc., and the present application may not specifically limit the type of electronic device.

[0068] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" 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 application. In this specification, the schematic representation of the above terms does 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.

[0069] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that: include: A housing (200), wherein a receiving chamber (201) is provided in the housing (200); A bare cell (100) is arranged in the accommodating cavity (201), and comprises a positive electrode sheet (10), a negative electrode sheet (20), an isolation film (30), and a piezoelectric sensor (40), wherein the positive electrode sheet (10) and the negative electrode sheet (20) are alternately arranged in the thickness direction, the isolation film (30) is arranged between the positive electrode sheet (10) and the negative electrode sheet (20), the piezoelectric sensor (40) is connected to the inside of the bare cell (100) and to the positive electrode sheet (10) or the negative electrode sheet (20), and the piezoelectric sensor (40) is used to receive a pressure signal from the positive electrode sheet (10) or the negative electrode sheet (20) and convert the pressure signal into an electrical signal.

2. The battery cell according to claim 1, characterized in that: The piezoelectric sensor (40) comprises a piezoelectric film (41) and a connector (42) connected to one side of the piezoelectric film (41); the piezoelectric film (41) is connected to the positive electrode sheet (10) or the negative electrode sheet (20) via the connector (42); the piezoelectric film (41) is used to receive a pressure signal from the positive electrode sheet (10) or the negative electrode sheet (20) and convert the pressure signal into an electrical signal.

3. The battery cell according to claim 2, characterized in that: A positive electrode tab (11) is provided on the positive electrode sheet (10), and the piezoelectric sensor (40) is connected to the negative electrode sheet (20) and is opposite to the positive electrode tab (11) along the thickness direction.

4. The battery cell according to claim 3, characterized in that: The negative electrode sheet (20) is provided with a negative electrode ear (21), the connecting member (42) is a conductive connecting member, the connecting member (42) is electrically connected to the negative electrode sheet (20), and the electrical signal is transmitted to the negative electrode ear (21) through the conductive connecting member and the negative electrode sheet (20), so as to transmit the electrical signal to the outside of the battery cell.

5. The battery cell according to claim 4, characterized in that: The conductive connecting member (42) comprises at least one of a graphene-based adhesive and an aluminum layer conductive adhesive.

6. The battery cell according to claim 3, characterized in that: The connecting piece (42) is an insulating connecting piece. The battery cell further comprises a signal transmission piece (50). The signal transmission piece (50) is connected to the piezoelectric film (41) and is at least partially exposed outside the shell (200). The signal transmission piece (50) is used to transmit the electrical signal of the piezoelectric film (41) to the outside of the battery cell.

7. The battery cell according to claim 6, characterized in that: A positive electrode tab (11) is provided on the positive electrode sheet (10), and the piezoelectric sensor (40) is connected to the negative electrode sheet (20) and is opposite to the positive electrode tab (11) along the thickness direction.

8. The battery cell according to claim 6, characterized in that: A negative electrode tab (21) is provided on the negative electrode sheet (20), and the piezoelectric sensor (40) is connected to the positive electrode sheet (10) and is opposite to the negative electrode tab (21) along the thickness direction.

9. The battery cell according to claim 2, characterized in that: The piezoelectric film (41) comprises at least one of a silicon dioxide piezoelectric film (41), a carbon fiber piezoelectric film (41), and a semiconductor piezoelectric film (41).

10. An electronic device, characterized in that: Comprising the battery cell as claimed in any one of claims 1 to 9.

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