Battery cell, energy storage device, and electric vehicle

Abstract

The application provides a battery monomer, an energy storage device and an electric vehicle. The battery monomer comprises a battery cell and a battery cell monitoring device, and the battery cell monitoring device comprises a sensor unit and a power supply unit. The sensor unit is located on the negative electrode and fixed to the surface of the negative electrode current collector, and the battery cell supplies power to the sensor unit through the power supply unit. The sensor unit comprises a sensor module and a signal modulator, and the sensor module sends a battery cell parameter signal to the signal modulator through a signal line. The power supply unit supplies power to the sensor unit through a conductive line. The signal line and the conductive line are both etched circuits etched on the surface of the negative electrode current collector. The application fixes the battery cell monitoring device to the surface of the negative electrode current collector and etches the signal line and the conductive line on the surface of the negative electrode current collector, which can solve the problem that the volume of the battery cell monitoring device is too large and the structure is too complex, thereby affecting the capacity of the battery cell.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a battery cell, an energy storage device, and an electric vehicle. Background Technology

[0002] Batteries are widely used in electric vehicles, energy storage, and other fields. As battery safety requirements become increasingly stringent, it is difficult to accurately and promptly assess the internal state of a battery cell using only external parameters such as current and voltage. Therefore, placing sensors inside the cell to monitor its state is crucial for precise management of cell safety and health. However, placing sensors inside the cell occupies internal space, negatively impacting the cell's internal structure and capacity. Therefore, obtaining cell parameters without affecting the cell's internal structure and capacity is a key technological challenge in battery development. Summary of the Invention

[0003] In a first aspect, this application proposes a battery cell, comprising a battery cell and a battery cell monitoring device. The battery cell includes a separator, a positive electrode, a negative electrode, a positive current collector, and a negative current collector. The battery cell monitoring device includes a sensor unit and a power supply unit. The sensor unit is disposed on the negative electrode and fixed to the surface of the negative current collector. The sensor unit is used to collect battery cell parameters and output at least one parameter signal. The battery cell supplies power to the sensor unit through the power supply unit.

[0004] This application solves the problem of excessive space occupied by the monitoring device within the battery cell by placing the sensor unit on the negative electrode and fixing it to the surface of the negative electrode current collector. Specifically, fixing the sensor unit to the surface of the negative electrode current collector eliminates the need for fixing structural components, thereby reducing the size of the battery cell monitoring device. Furthermore, fixing the sensor unit to the surface of the negative electrode current collector allows all related wiring harnesses to be arranged close to the surface of the negative electrode current collector without requiring additional circuit connections, thus simplifying the structure of the battery cell device.

[0005] The power supply unit in this application draws power directly from the battery cell. The power supply unit uses the electrical energy in the battery cell to power the sensor unit without the need to set up a separate power supply for the battery cell monitoring device, thereby simplifying the structure of the battery cell monitoring device, reducing manufacturing costs, and reducing the space occupied by the battery cell monitoring device.

[0006] In one possible implementation, the sensor unit includes a sensor module and a signal modulator. The sensor module includes at least one sensor, which is used to acquire cell parameters, convert the cell parameters into cell parameter signals, and send the cell parameter signals to the signal modulator. The signal modulator is used to receive the cell parameter signals and modulate the cell parameter signals into cell parameter modulated signals.

[0007] In one possible implementation, the cell monitoring device includes signal lines and conductive lines. The signal lines connect a sensor and a signal modulator, with the sensor transmitting cell parameter signals to the signal modulator via the signal lines. The conductive lines connect a power supply unit and a sensor unit, with the power supply unit receiving power from the cell and supplying power to the sensor unit via the conductive lines.

[0008] Both the signal lines and the conductive lines are etched circuits etched onto the surface of the negative electrode current collector.

[0009] This application simplifies the structure of the battery cell monitoring device and reduces its additional footprint by setting the signal lines and conductive lines as etched circuits on the negative electrode current collector. Specifically, the negative electrode current collector is made of copper, which has good conductivity. Therefore, this application etches the signal lines and conductive lines on the surface of the negative electrode current collector without using conductive wire harnesses. Etching the signal lines and conductive lines on the negative electrode current collector saves on wire harnesses, simplifies the structure of the battery cell monitoring device, reduces the space occupied, and lowers the manufacturing cost of the battery cell monitoring device.

[0010] In one possible implementation, the negative electrode of the battery cell includes an excess negative electrode region. The excess negative electrode region is the portion of the negative electrode that extends beyond the positive electrode in both length and width. The sensor unit and the power supply unit are located in the excess negative electrode region and fixed to the surface of the negative electrode current collector.

[0011] This application reduces the impact of the cell monitoring device on the cell capacity by placing the sensor unit and power supply unit in the negative electrode excess region. Specifically, the negative electrode excess region is a redundant design to protect battery safety, and its impact on battery capacity is relatively small compared to the negative electrode body. In this embodiment, the cell monitoring device is arranged in the negative electrode excess region. Although the cell monitoring device occupies part of the space in the negative electrode excess region, since the negative electrode excess region does not participate in cell charging and discharging, the cell monitoring device does not affect the cell energy density.

[0012] In one possible implementation, at least one sensor is attached to the diaphragm. The at least one sensor attached to the diaphragm is used to acquire diaphragm parameters and convert the diaphragm parameters into diaphragm parameter signals.

[0013] This application utilizes at least one sensor attached to the separator to collect separator parameters, enabling more timely and effective monitoring of the cell's safety status. Specifically, a continuous increase in cell temperature can trigger thermal runaway. Thermal runaway refers to the phenomenon where the chemically active materials within the cell ignite and explode rapidly. Before thermal runaway occurs, the cell exhibits separator temperature rise, separator contraction, and changes in separator stress. Therefore, the temperature, stress, and strain parameters of the separator are crucial for determining cell thermal runaway. In this application, at least one sensor attached to the separator can promptly collect separator parameters, allowing the battery management system to monitor changes in the cell's safety status based on these parameter variations.

[0014] In one possible implementation, the sensor unit includes at least one of a temperature sensor, a pressure sensor, a stress sensor, or a strain sensor, wherein the temperature sensor, pressure sensor, stress sensor, and strain sensor are used to monitor the temperature, pressure, stress, and strain of the battery cell, respectively.

[0015] In one possible implementation, the sensor unit is connected to the battery management unit and outputs at least one cell parameter modulation signal to the battery management unit.

[0016] In a second aspect, this application proposes an energy storage device, which includes a battery pack and a battery management system. The battery pack includes multiple battery cells as described in the first aspect, and the battery management system includes a battery management unit and a battery management controller. The battery management unit is used to receive cell parameter modulation signals sent by a sensor unit and send signals to the battery management controller.

[0017] In one possible implementation, the battery management system (BMS) determines the safety of individual battery cells based on separator parameters. The BMS outputs a safety warning signal in response to a separator temperature exceeding a preset separator temperature, or in response to a separator stress exceeding a preset separator stress, or a separator strain exceeding a preset separator strain. The battery management controller then issues a safety warning in response to the BMS outputting the safety warning signal.

[0018] The battery management system proposed in this application can provide timely warnings of battery safety issues based on separator parameters. As mentioned earlier, the temperature, stress, and strain parameters of the separator are crucial for assessing battery cell safety. Therefore, the battery management system proposed in this application can provide more accurate and timely warnings of battery safety problems.

[0019] Thirdly, this application proposes an electric vehicle that includes a battery cell as described in the first aspect, or an energy storage device as described in the second aspect.

[0020] The electric vehicle proposed in this application can improve its driving range by incorporating battery cells as described in the first aspect. Specifically, because the cell monitoring device occupies a small internal space within the cell, as described in the first aspect, it has a smaller impact on the cell's energy density, resulting in a larger stored energy within the cell. Therefore, electric vehicles equipped with battery cells as described in the first aspect have a longer driving range.

[0021] The electric vehicle proposed in this application can improve its safety by incorporating the energy storage device as described in the second aspect. Specifically, the battery management system of the energy storage device as described in the second aspect can monitor the battery's safety status in a timely and accurate manner; therefore, electric vehicles equipped with the energy storage device as described in the second aspect have higher safety. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of an energy storage device;

[0023] Figure 2 This is a schematic diagram of an electric vehicle;

[0024] Figure 3 A schematic diagram of a single battery cell provided in an embodiment of this application;

[0025] Figure 4 A schematic diagram of a battery cell in a single battery cell provided in an embodiment of this application;

[0026] Figure 5 This is another schematic diagram of a battery cell provided in an embodiment of this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0029] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0030] Figure 1 An energy storage device is described. The energy storage device 1 includes a battery pack 11 and a battery management system 12. The battery pack 11 stores electrical energy, and the battery management system 12 manages the battery pack 11. The battery pack 11 includes multiple battery modules 111, and each battery module includes multiple battery cells. Each battery cell includes a positive current collector, a positive electrode, a separator, a negative electrode, and a negative current collector. The battery management system 12 includes multiple battery management units 121 and a battery management controller 122. Each battery management unit 121 manages one battery module 111, and each battery cell in the battery module 111 is connected to the battery management unit 121. The battery management controller 122 is connected to the multiple battery management units 121 and receives signals from the battery management units 121.

[0031] The energy storage device 1 can be applied to different scenarios, such as photovoltaic power generation, wind power generation, and electric vehicle scenarios.

[0032] Figure 2 The electric vehicle 2 includes an energy storage device 1 as described above. A battery pack 11 provides electrical energy to power the electric vehicle, and a battery management system 12 manages the battery pack 11. For example, the battery management system 12 monitors the safety and health status of each individual battery cell in the battery pack 11.

[0033] In order to effectively manage individual battery cells, the battery management unit 121 needs to receive the cell parameters of each individual battery cell in a timely and accurate manner to determine the cell's safety and electrical health status. Therefore, each battery cell contains a cell monitoring device for monitoring cell parameters. The cell monitoring device is used to collect cell parameters and modulate the collected cell parameters into a cell parameter modulation signal before sending it to the battery management unit 121.

[0034] Understandably, cell monitoring devices need to be fixedly installed inside the battery cell, and must not affect the cell's sealing or normal expansion and charging / discharging. Furthermore, placing sensors inside the cell would occupy internal space, negatively impacting the cell's internal structure and capacity.

[0035] To address the above issues, embodiments of this application provide a battery cell, an energy storage device, and an electric vehicle.

[0036] Figure 3 This is a schematic diagram of a single battery cell provided in an embodiment of this application. Figure 3 As shown, the battery cell 4 includes a cell 41 and a cell monitoring device 42. The cell 41 is used to store electrochemical energy, and the cell monitoring device 42 is used to collect and output cell parameters. The cell monitoring device 42 is connected to the battery management unit 121, and is used to collect cell parameters, modulate the cell parameter signals into cell parameter modulation signals, and send the cell parameter modulation signals to the battery management unit 121.

[0037] Figure 4 This is a schematic diagram of a battery cell in a single battery cell provided as an embodiment of this application. Figure 4 As shown, the battery cell 41 includes a positive electrode 411, a negative electrode 412, a separator 413, a positive current collector 414, a negative current collector 415, and a negative electrode excess region 416. The positive electrode 411 is the end of the battery cell 41 with a higher potential and includes a positive active material. The negative electrode 412 is the end of the battery cell 41 with a lower potential and also includes a negative active material. The separator 413 is located between the positive electrode 411 and the negative electrode 412, separating them. The positive current collector 414 is a thin metal layer coated with the positive active material, serving to carry the positive active material and conduct current. The negative current collector 415 is a thin metal layer coated with the negative active material, serving to carry the negative active material and conduct current.

[0038] The negative electrode excess region 416 is the portion of the negative electrode 412 that extends beyond the positive electrode 411 in length and width. In one embodiment, the cell 41 is a lithium-ion battery cell. During the movement of lithium ions from the positive electrode 411 to the negative electrode 412, the negative electrode excess region 416 provides sufficient lithium ion insertion vacancies. The negative electrode excess region 416 can prevent lithium ions from precipitating on the surface of the negative electrode 412 and forming lithium dendrites. Lithium dendrites are metallic crystals formed by the accumulation of lithium ions in a lithium-ion battery. The continuous growth of lithium dendrites can pierce the separator, inducing a short circuit within the lithium battery and posing a significant threat to battery safety. Therefore, the negative electrode excess region 416 is a redundant design to protect the cell's safety, and its impact on the cell's capacity is relatively small compared to the negative electrode 412 itself.

[0039] In one embodiment, cell 41 is a lead-acid battery cell. In one embodiment, cell 41 is a sodium-ion battery cell. In one embodiment, cell 41 is an aluminum-ion battery cell. In one embodiment, cell 41 is a potassium-ion battery cell. In one embodiment, cell 41 is a lithium-ion battery cell.

[0040] In one embodiment, cell 41 is a wound square battery cell. In one embodiment, cell 41 is a stacked square battery cell. In one embodiment, cell 41 is a pouch battery cell. In one embodiment, cell 41 is a cylindrical battery cell.

[0041] Figure 5 This is another schematic diagram of a battery cell provided in an embodiment of this application. (See diagram below.) Figure 5 As shown, the battery cell monitoring device 42 includes a sensor unit 421 and a power supply unit 422. The sensor unit 421 is located in the negative electrode 412 region and fixed to the surface of the negative electrode current collector 415. The sensor unit 421 is used to collect parameters of the battery cell 41 and output at least one parameter signal. The power supply unit 422 is connected to the positive electrode 411 and the negative electrode 412 to draw power from the battery cell 41 and supply power to the sensor unit 421.

[0042] Specifically, the sensor unit 421 is connected to the power supply unit 422. The power supply unit 422 draws power from the battery cell 41 to power the sensor unit 421. After being powered on, the sensor unit 421 is in working state. In working state, the sensor unit 421 collects relevant parameters of the battery cell 41 and modulates the collected parameters into parameter modulation signals and outputs them to the battery management unit 121.

[0043] In one embodiment, sensor unit 421 acquires the temperature parameter of the negative electrode of the battery cell and modulates the negative electrode temperature parameter into a negative electrode temperature modulation signal for output. In one embodiment, sensor unit 421 acquires the stress parameter of the negative electrode of the battery cell and modulates the negative electrode stress parameter into a negative electrode stress modulation signal for output. In one embodiment, sensor unit 421 acquires the air pressure parameter of the negative electrode of the battery cell and modulates the negative electrode air pressure parameter into a negative electrode air pressure modulation signal for output.

[0044] The sensor unit 421 provided in this embodiment includes a sensor module 4211, a signal modulator 4212, and a signal line 4213. The sensor module 4211 collects cell parameters and converts them into cell parameter signals. The sensor module 4211 then transmits the cell parameter signals to the signal modulator 4212 via the signal line 4213. The signal modulator 4212 receives and modulates the cell parameter signals and outputs the modulated cell parameter signals to the battery management unit 121.

[0045] In this embodiment, the signal line 4213 is an etched circuit etched onto the surface of the negative electrode current collector. The signal line 4213 is used for signal transmission between the sensor module 4211 and the signal modulator 4212. Specifically, the sensor module 4211 sends the collected cell signal parameters to the signal modulator 4212 via the signal line 4213. Both the sensor module 4211 and the signal modulator 4212 are fixed to the surface of the negative electrode current collector 415, and the material of the negative electrode current collector 415 is copper, which has good conductivity. Therefore, in this embodiment, the signal line 4213 is an etched circuit formed on the surface of the negative electrode current collector 415. Compared to using wires to connect the sensor module 4211 and the signal modulator 4212, etched lines can reduce the use of wires, lower costs, simplify the structure of the cell monitoring device 42, and reduce the volume occupied by the cell monitoring device 42.

[0046] In this embodiment, the sensor module 4211 includes multiple sensors for acquiring parameters of the battery cell 41. The sensor module 4211 includes a temperature sensor, a pressure sensor, a stress sensor, and a strain sensor. Specifically, the temperature sensor acquires the battery cell temperature parameter, the pressure sensor acquires the battery cell pressure signal, the stress sensor acquires the battery cell stress signal, and the strain sensor acquires the battery cell strain signal.

[0047] In this embodiment, the sensor unit 421 includes a temperature sensor, a stress sensor, and a strain sensor, one end of which is fixed to the surface of the negative electrode current collector 415, and the other end of which is attached to the separator. The temperature sensor, stress sensor, and strain sensor are used to collect separator temperature parameters, separator stress parameters, and separator strain parameters, and convert these parameters into separator temperature parameter signals, separator stress parameter signals, and separator strain parameter signals, respectively. The signal modulator 4212 receives the separator temperature parameter signals, separator stress parameter signals, and separator strain parameter signals, and outputs the separator temperature parameter modulation signal, separator stress parameter modulation signal, and separator strain parameter modulation signal to the battery management unit 121.

[0048] A continuous increase in the temperature of the battery cell 41 can trigger thermal runaway. Thermal runaway refers to the phenomenon where the chemically active materials inside the battery cell 41 ignite and explode rapidly. Before thermal runaway occurs, the temperature of the separator 413 rises, the separator 413 contracts, and the stress of the separator 413 changes. Therefore, the temperature, stress, and strain parameters of the separator 413 are of great significance for judging the thermal runaway of the battery cell. In this embodiment, the sensor unit 421 sends the separator temperature parameter modulation signal, the separator stress parameter modulation signal, and the separator strain parameter modulation signal to the battery management unit 121. The battery management unit 121 can determine the safety status of the battery cell based on the received separator 413 parameters.

[0049] In this embodiment, each sensor in sensor unit 421 is a micrometer-scale sensor. Specifically, the dimensions of each sensor in sensor unit 421 are all on the micrometer scale. In one embodiment, the sensor is a square sensor, with its length, width, and height all between 1 and 1000 micrometers. In another embodiment, the sensor is a cylindrical sensor, with its height and base diameter both between 1 and 1000 micrometers. In yet another embodiment, the sensor is a spherical sensor, with its diameter between 1 and 1000 micrometers.

[0050] Each sensor in the sensor unit 421 of this application embodiment is a micron-level sensor. Micron-level sensors are smaller in size and occupy less space within the battery cell, resulting in less loss of battery cell capacity.

[0051] In this embodiment, the power supply unit 422 draws power from the battery cell 41 to supply power to the sensor unit 421 by connecting the positive terminal and the negative terminal.

[0052] In this embodiment, the power supply unit 422 draws power directly from the battery cell. The power supply unit 422 uses the electrical energy in the battery cell 41 to power the sensor unit 421 without the need to set up a separate power supply for the battery cell monitoring device 42, thereby simplifying the structure of the battery cell monitoring device 42, reducing manufacturing costs, and reducing the space occupied by the battery cell monitoring device 42.

[0053] In this embodiment, the cell monitoring device 42 further includes a conductive line 4222, which is etched on the surface of the negative electrode current collector. The cell 41 supplies power to the sensor unit 421 through the conductive line.

[0054] The negative electrode current collector 415 is made of copper, which has good conductivity. Therefore, in this embodiment, conductive lines 4222 are etched on the surface of the negative electrode current collector 415. The conductive lines 4222 connect the power supply unit 422 and the sensor unit 421. Since the conductive lines 4222 are circuits etched on the negative electrode current collector, there is no need to use conductive wire harnesses to connect the power supply unit 422 and the sensor unit 421, thereby saving wire harnesses, simplifying the structure of the cell monitoring device 42, reducing the space occupied by the cell monitoring device 42, and reducing the manufacturing cost of the cell monitoring device 42.

[0055] In one embodiment, the cell monitoring device 42 is located in the negative electrode excess region 416. The sensor unit 421 and the power supply unit 422 are both located in the negative electrode excess region 425 and fixed to the surface of the negative electrode current collector 415. The sensor module 4211 and the signal modulator 4212 of the sensor unit 421 are connected via signal lines 4213 etched on the surface of the negative electrode current collector 415. The power supply unit 422 and the sensor unit 421 are connected via conductive lines 4222 etched on the surface of the negative electrode current collector 415.

[0056] The negative electrode excess region 416 is a redundant design to protect battery safety. The negative electrode excess region 416 has a relatively small impact on the battery capacity compared to the negative electrode 412 itself. In this embodiment, the cell monitoring device 42 is arranged in the negative electrode excess region 416. Although the cell monitoring device 42 occupies part of the space in the negative electrode excess region 416, since the negative electrode excess region 416 does not participate in the charging and discharging of the cell, the cell monitoring device 42 does not affect the energy density of the cell 41.

[0057] In this embodiment, the sensor unit 421 is connected to the battery management unit 121 and outputs at least one cell 41 parameter signal to the battery management unit 121. Specifically, the signal modulator 4212 of the sensor unit 421 is connected to the battery management unit 121. The signal modulator 4212 sends the generated modulation signal to the battery management unit 121, and the battery management unit 121 demodulates the received modulation signal. In one embodiment, the signal modulator 4212 sends the generated temperature modulation signal to the battery management unit, and the battery management unit 121 demodulates the received temperature modulation signal. In one embodiment, the signal modulator 4212 sends the generated air pressure modulation signal to the battery management unit 121, and the battery management unit 121 demodulates the received air pressure modulation signal. In one embodiment, the signal modulator 4212 sends the generated stress modulation signal to the battery management unit 121, and the battery management unit 121 demodulates the received stress modulation signal.

[0058] This application provides an energy storage device, which includes a battery pack 11 and a battery management system 12. The battery pack 11 includes a plurality of battery cells 4 as described above. Specifically, the battery pack 11 includes a plurality of battery modules 111, and each battery module 111 includes a plurality of battery cells 4 as described above. Each battery module 111 has a corresponding battery management unit 121, which is connected to each battery cell 4 in the battery module 111. The battery management unit 121 is used to receive cell parameter modulation signals from the battery cells 4. A battery management controller 122 is connected to the battery management unit 121 and is used to process the signals from the battery management unit 121. For example, a temperature sensor collects the temperature parameters of the cell 41 and sends the temperature parameters to a signal modulator 4212 through a signal line 4213. The 4212 modulates the temperature parameters into a temperature parameter modulation signal and sends the temperature parameter modulation signal to the battery management unit 121. The battery management unit 121 demodulates the temperature parameter modulation signal and sends the result to the battery management controller 122.

[0059] In this embodiment, the battery management unit 121 is used to determine the risk of thermal runaway of the battery cell 42 based on the parameters of the battery cell 42. The battery management unit 121 outputs a thermal runaway warning signal in response to the separator temperature exceeding a preset separator temperature. The battery management unit 121 also outputs a thermal runaway warning signal in response to the separator stress exceeding a preset separator stress or separator strain exceeding a preset separator strain. The battery management controller 122 receives the thermal runaway warning signal and issues its own thermal runaway warning in response to the output of the thermal runaway warning signal by the battery management unit 121.

[0060] In this embodiment, the sensor attached to the separator is used to collect separator parameters. The signal modulator 4212 receives the separator parameters and modulates them into a separator parameter modulation signal. The battery management unit 121 receives the modulation signal from the signal modulator 4212 and demodulates it. The battery management unit 121 determines the safety status of the current battery cell based on the separator parameters. If the current battery cell has a risk of thermal runaway, the battery management unit 121 sends a thermal runaway warning signal to the battery management controller 122. The battery management controller 122 receives the thermal runaway warning signal from the battery management unit 121 and issues a thermal runaway warning.

[0061] For example, a temperature sensor attached to the separator collects separator temperature parameters and converts these parameters into a separator temperature parameter signal, which is then sent to a signal modulator 4212. The signal modulator 4212 modulates the separator temperature signal into a separator temperature modulated signal and sends it to the battery management unit 121. The battery management unit 121 demodulates the separator parameter modulated signal and compares the separator temperature with a preset separator temperature. If the separator temperature exceeds the preset separator temperature, indicating an abnormally high separator temperature and a risk of thermal runaway in the battery cell, the battery management unit 121 sends a thermal runaway warning signal to the battery management controller 122. Upon receiving the thermal runaway warning signal from the battery management unit 121, the battery management controller 122 issues a thermal runaway warning.

[0062] For example, a stress sensor attached to the separator collects separator stress parameters and converts them into separator stress parameter signals, which are then sent to a signal modulator 4212. The signal modulator 4212 modulates the separator stress parameters into a separator stress parameter modulated signal and sends the modulated signal to the battery management unit 121. The battery management unit 121 demodulates the separator stress parameter modulated signal and compares the separator stress with a preset separator stress. If the separator stress exceeds the preset separator stress, indicating an abnormally high separator stress and separator contraction, and a risk of thermal runaway in the battery cell, the battery management unit 121 sends a thermal runaway warning signal to the battery management controller 122. Upon receiving the thermal runaway warning signal from the battery management unit 121, the battery management controller 122 issues a thermal runaway warning.

[0063] For example, a strain sensor attached to the diaphragm collects the diaphragm strain parameters and converts them into a diaphragm strain parameter signal, which is then sent to a signal modulator 4212. The signal modulator 4212 modulates the diaphragm strain parameters into a diaphragm strain parameter modulated signal and sends this signal to the battery management unit 121. The battery management unit 121 demodulates the diaphragm strain parameter modulated signal and compares the diaphragm strain with a preset diaphragm strain. If the diaphragm strain exceeds the preset strain, indicating an abnormally high strain and diaphragm contraction, and a risk of thermal runaway in the battery cell, the battery management unit 121 sends a thermal runaway warning signal to the battery management controller 122. Upon receiving the thermal runaway warning signal from the battery management unit 121, the battery management controller 122 issues a thermal runaway warning.

[0064] This application provides an electric vehicle, which includes a battery pack 11 and a battery management system 12. The battery pack 11 includes a plurality of battery cells 4 as described above. The battery management system 12 includes a battery management unit 121 and a battery management controller 122. Specifically, the battery pack 11 includes a plurality of battery modules 111, and each battery module 111 includes a plurality of battery cells 4 as described above. Each battery module 111 has a corresponding battery management unit 121, which is connected to each battery cell 4 in the battery module 111. The battery management unit 121 is used to receive cell parameter modulation signals from the battery cells 4. The battery management controller 122 is connected to the battery management unit 121 and is used to process the signals from the battery management unit 121. For example, the temperature sensor collects the temperature parameters of the battery cell 41 and sends the temperature parameters to the signal modulator 4212 through the signal line 4213. 4212 modulates the temperature parameters into a temperature parameter modulation signal and sends the temperature parameter modulation signal to the battery management unit 121. The battery management unit 121 demodulates the temperature parameter modulation signal and sends the result to the battery management controller 122.

[0065] In this embodiment, the battery management unit 121 is used to determine the risk of thermal runaway of the cell 42 based on the parameters of the cell 42. In response to the separator temperature exceeding a preset separator temperature, the battery management unit 121 receives a separator temperature modulation signal and outputs a thermal runaway warning signal. In response to the separator strain exceeding a preset separator strain, the battery management unit 121 receives a separator strain modulation signal and outputs a thermal runaway warning signal. In response to the battery management unit outputting the thermal runaway warning signal, the battery management controller 122 receives the thermal runaway warning signal and issues a thermal runaway warning.

[0066] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although the preferred embodiments of this application have been disclosed above, they are not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A battery cell, characterized by, The battery cell comprises a cell core and a cell core monitoring device, the cell core comprises a separator, a positive electrode, a negative electrode, a positive electrode current collector and a negative electrode current collector; The cell core monitoring device comprises a sensor unit and a power supply unit; the negative electrode comprises a negative electrode excess area, which is the part of the length and width of the negative electrode that exceeds the positive electrode; the sensor unit and the power supply unit are located in the negative electrode excess area and fixed to the surface of the negative electrode current collector; The sensor unit is used to collect cell parameters and output at least one parameter signal, and the cell supplies power to the sensor unit through the power supply unit.

2. The battery cell of claim 1, wherein, The sensor unit comprises a sensor module and a signal modulator, wherein: The sensor module comprises at least one sensor, which is used to collect cell parameters, convert cell parameters into cell parameter signals and send cell parameter signals to the signal modulator; The signal modulator is used to receive the cell parameter signals and modulate the cell parameter signals into cell parameter modulated signals and output to the outside of the cell.

3. The battery cell of claim 2, wherein, The cell core monitoring device comprises a signal line and a conductive line, wherein: The signal line is used to connect the sensor and the signal modulator, and the sensor sends cell parameter signals to the signal modulator through the signal line; The conductive line is used to connect the power supply unit and the sensor unit, and the power supply unit receives the cell power supply and supplies power to the sensor unit through the conductive line; The signal line and the conductive line are both etched circuits etched on the surface of the negative electrode current collector.

4. The battery cell of claim 2, wherein, At least one of the sensors is attached to the separator, and the at least one sensor attached to the separator is used to collect parameters of the separator and convert the parameters of the separator into separator parameter signals.

5. The battery cell of any one of claims 1-4, wherein, The sensor unit comprises at least one of a temperature sensor, a gas pressure sensor, a stress sensor or a strain sensor, which are respectively used to monitor the temperature, gas pressure, stress and strain of the cell.

6. The battery cell of claim 2, wherein, The sensor unit is connected to the battery management unit and outputs the at least one cell parameter modulated signal to the battery management unit.

7. An energy storage device comprising a battery pack and a battery management system, characterized in that, The battery pack comprises a plurality of battery cells as claimed in any one of claims 1-6, and the battery management system comprises a battery management unit and a battery management controller, the battery management unit is used to receive the cell parameter modulated signals sent by the sensor unit and send signals to the battery management controller.

8. The energy storage device of claim 7, wherein, The battery management system is used to determine the safety of the battery cell according to the parameters of the separator: In response to the temperature of the separator being greater than a preset separator temperature, the battery management unit receives the separator temperature signal and outputs a safety warning signal; Or, In response to the stress of the separator being greater than a preset separator stress or the strain of the separator being greater than a preset separator strain, the battery management unit receives the separator stress signal or the separator strain signal and outputs a safety warning signal; Or, In response to the battery management unit outputting the safety warning signal, the battery management controller receives the safety warning signal and issues a safety warning.

9. An electric vehicle, characterized by The electric vehicle comprises the battery cell as claimed in any one of claims 1 to 6, or the electric vehicle comprises the energy storage device as claimed in claim 7 or 8.

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