Battery safety screening device based on EIS, charging pile and mobile electric equipment

Abstract

The utility model discloses a battery safety screening device based on an EIS, a charging pile and mobile electric equipment. The battery safety screening device based on the EIS is used for electrically connecting a charging pile and a battery pack of electric equipment, and comprises a charging control module which is connected in series with the charging pile and the battery pack and is used for connecting or disconnecting a charging circuit of the charging pile and the battery pack; the impedance detection module is electrically connected with the positive end and the negative end of the battery pack and is used for acquiring disturbance signals of the positive end and the negative end of the battery pack and analyzing the alternating current impedance of the battery pack based on the disturbance signals; the current detection module is connected in series with the charging pile and the battery pack and is used for detecting charging current in the charging circuit; the voltage detection module is connected with the battery pack in parallel and used for detecting voltage of the battery pack. Before charging, the alternating current impedance of the battery pack is measured to judge whether a chargeable condition is met or not, and in the charging process, the battery voltage and the charging current are monitored, the battery safety is monitored in time, and risks are avoided in time.

Description

TECHNICAL FIELD

[0001] The utility model relates to new energy battery management technical field especially, it relates to a battery safety screening device based on EIS, charging pile, mobile electric equipment. BACKGROUND

[0002] With the extension of the use time and the increase of the charge and discharge cycle number, the battery pack is prone to aging in the normal operation process. The battery aging involves internal lithium dendrite precipitation or battery lug virtual welding and other problems, and further causes the continuous rise of the internal resistance of the battery pack. The increase of the internal resistance will cause the increase of the heat generated by the heat dissipation of the battery pack under the same charging current condition. The accumulation of heat may cause the thermal runaway phenomenon of the battery pack in the charging process, and further cause the fire accident. For the safety problems of a large number of stock electric bicycles on the market, and the effectiveness of the protection circuit after the electric bicycle is used for 5 years or 10 years, there is no clear solution at present. In the prior art field, impedance measurement is usually realized by means of an internal resistance meter. However, the internal resistance meter is often only suitable for a specific single scene in actual application, and its industrial application is difficult and the cost is high. SUMMARY

[0003] In view of the defects of the prior art, the purpose of the utility model is to provide a battery safety screening device based on EIS, a charging pile and a mobile electric equipment.

[0004] In order to realize the foregoing utility model purposes, the utility model adopts the technical scheme of:

[0005] The utility model provides a battery safety screening device based on EIS for the first aspect, which is used for electrically connecting a charging pile and a battery pack of an electric equipment, and the battery safety screening device comprises:

[0006] A charging control module is connected in series with the charging pile and the battery pack, and is used for turning on or turning off the charging circuit of the charging pile and the battery pack;

[0007] An impedance detection module is electrically connected with the positive and negative terminals of the battery pack, and is used for collecting the disturbance signal of the positive and negative terminals of the battery pack, and obtaining the alternating current impedance of the battery pack based on the disturbance signal analysis;

[0008] A current detection module is connected in series with the charging pile and the battery pack, and is used for detecting the charging current in the charging circuit;

[0009] A voltage detection module is connected in parallel with the battery pack, and is used for detecting the voltage of the battery pack.

[0010] In some more specific embodiments, the current detection module at least includes a current detection resistor, a proportional amplifier, and a single-chip microcomputer, the current detection resistor is connected with the input end of the proportional amplifier, the single-chip microcomputer is connected with the output end of the proportional amplifier, the current detection resistor is used to convert the current signal into a voltage signal, the proportional amplifier is used to amplify the voltage signal, and the single-chip microcomputer is used to collect the voltage signal to detect the charging current in the charging circuit.

[0011] In some more specific embodiments, the current detection module at least includes a Hall sensor, a proportional amplifier, and a single-chip microcomputer, the Hall sensor is connected with the input end of the proportional amplifier, the single-chip microcomputer is connected with the output end of the proportional amplifier, the Hall sensor is used to convert the current signal into a voltage signal, the proportional amplifier is used to amplify the voltage signal, and the single-chip microcomputer is used to collect the voltage signal to detect the charging current in the charging circuit.

[0012] In some more specific embodiments, the voltage detection module at least includes an ADC converter.

[0013] In some more specific embodiments, the impedance detection module at least includes an alternating current injection end, an alternating voltage feedback end, and an alternating resistance calculation end,

[0014] The alternating current injection end is used to inject an alternating current signal with a frequency of

[0015] The alternating voltage feedback end is used to collect an alternating voltage signal fed back by the battery

[0016] The alternating resistance calculation end is used to calculate the alternating internal resistance value of the battery according to the alternating current signal and the alternating voltage signal .

[0017] In some more specific embodiments, the EIS-based battery safety screening device further includes a master control chip, the master control chip is connected with the charging control module, the impedance detection module, the current detection module, and the voltage detection module, and the master control chip includes a state display area, a battery information setting area, a threshold setting area, and a calculation area,

[0018] The state display area is used to display the voltage of the battery pack, the charging current in the charging circuit, and the alternating impedance of the battery pack.

[0019] The battery information setting area is used to set the rated capacity and voltage platform of the battery pack. ​​​​

[0020] The threshold setting region is configured to preset battery thresholds, including voltage thresholds, charging current thresholds, internal resistance thresholds, and AC impedance thresholds.

[0021] The calculation region is configured to calculate AC impedance and match the voltage of the battery pack, the charging current in the charging circuit, and the AC impedance of the battery pack with the battery thresholds to obtain a battery fault detection result.

[0022] Further, the EIS-based battery safety screening device further comprises an alarm module, which at least includes a sound alarm and an alarm light.

[0023] Further, the charging control module is connected with the master control chip and is configured to cut off the circuit when the battery fault detection result is abnormal.

[0024] In some more specific embodiments, the EIS-based battery safety screening device further comprises a power module, which includes a first output power and a second output power.

[0025] The first output power is configured to filter and step down the externally provided power, convert it into the voltage required by the internal circuit, and output it to the current detection module and the voltage detection module.

[0026] The second output power is configured to output the power to the impedance detection module.

[0027] The second aspect of the utility model provides a charging pile, the charging pile is provided with the EIS-based battery safety screening device.

[0028] The third aspect of the utility model provides a mobile electrical equipment, and the mobile electrical equipment is provided with the EIS-based battery safety screening device.

[0029] Compared with the prior art, the utility model has at least the following advantages:

[0030] First, the utility model provides a kind of battery safety screening device based on EIS, the charging current, voltage, impedance of battery is detected respectively by current detection module, voltage detection module, impedance detection module, ensure that overvoltage and overcurrent do not appear, guarantee charging safety.And before charging, measure battery package ac impedance, to judge whether the battery package meets chargeable condition.No matter is inventory or increment, first do an ac impedance screening when charging access, can identify electric bicycle with security risk to a great extent, to refuse access when charging, guarantee charging safety.

[0031] Second, the utility model provides a kind of battery safety screening device based on EIS, threshold setting area of main control chip can be according to the battery type of matched charging pile adaptation, preset voltage threshold value, charging current threshold value, internal resistance threshold value, ac impedance threshold value in advance, better applicability.

[0032] Third, the utility model provides a kind of battery safety screening device based on EIS, the switch of circuit is controlled by charging control module, guarantee power supply is cut off in time under abnormal condition, guarantee safety.The charging control module is in disconnected state when not accessing battery.When accessing battery and the battery detection of this access is normal, charging control module opens, guarantee battery can be normally charged.If abnormal state of battery is detected during charging, such as internal resistance is too large, or voltage is too high, charging will be closed and disconnected until state recovers normal.

[0033] Fourth, the utility model provides a kind of battery safety screening device based on EIS, sound alarm is used for when battery fault detection result is abnormal, sends early warning sound.Alarm lamp is used for when battery fault detection result is abnormal, sends early warning light.This can timely remind personnel to handle exception, avoid happening out of control risk.

[0034] Fifth, the utility model provides a kind of battery safety screening device based on EIS, first output power supply is used for filtering and voltage reduction to the power supply provided outside, convert into the voltage required by internal circuit, and output to current detection module, voltage detection module, the requirement of charging pile is lower, and adaptation is more flexible.Second output power supply is used for output power supply to impedance detection module, guarantee internal resistance detection module normal stable work. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is the structure schematic diagram of a kind of battery safety screening device based on EIS provided in the utility model embodiment;

[0036] Figure 2 It is the application structure schematic diagram of a kind of battery safety screening device based on EIS provided in the utility model embodiment;

[0037] Figure 3 is a structural schematic diagram of a current detection module provided by an embodiment of the present application;

[0038] Figure 4 is a structural schematic diagram of a current detection module provided by an embodiment of the present application;

[0039] Figure 5 is a process flow diagram of a battery safety screening device based on EIS provided by an embodiment of the present application. DETAILED DESCRIPTION

[0040] In view of the deficiencies in the prior art, the present inventors have long studied and practiced to propose the technical solution of the present application. The technical solution, its implementation process and principles will be further explained and described as follows.

[0041] Referring to Figures 1-2 The embodiment of the present application provides a battery safety screening device based on EIS, which is applied to an output end of a direct-current charging pile or a charging access end of an electric bicycle, and comprises:

[0042] A charging control module is connected in series with the charging pile and the battery pack, and is used for turning on or off a charging circuit of the charging pile and the battery pack.

[0043] An impedance detection module is electrically connected with positive and negative terminals of the battery pack, and is used for collecting disturbance signals of the positive and negative terminals of the battery pack, and obtaining an alternating current impedance of the battery pack based on the disturbance signals.

[0044] A current detection module is connected in series with the charging pile and the battery pack, and is used for detecting a charging current in the charging circuit.

[0045] A voltage detection module is connected in parallel with the battery pack, and is used for detecting a voltage of the battery pack.

[0046] An alarm module is connected with the impedance detection module, the current detection module and the voltage detection module, and is used for sending a warning signal when the alternating current impedance, the charging current and the voltage are detected to be abnormal.

[0047] In the present solution, the alternating current impedance spectrum of the battery pack can be obtained according to the charging current, the voltage and the internal resistance value. EIS (Electrochemical Impedance Spectroscopy) can represent the internal resistance value of the battery cell at different frequencies. Usually, Nyquist or Bode diagrams can be used to form the alternating current impedance spectrum. According to the alternating current impedance spectrum, the battery safety state of the battery pack can be detected.

[0048] The charging control module is used for cutting off the circuit in time when the battery fault detection result is abnormal. The charging control module is connected with the master control chip. In other words, the master control chip can control the charging control module according to the battery fault detection result, and then control the switch of the whole circuit, so as to cut off the power supply in time in the abnormal condition of the circuit and ensure the safety.

[0049] Specifically, the charging control module is in a disconnected state when no battery is connected. When a battery is connected and the connected battery is detected to be normal, the charging control module is turned on, so that the battery can be normally charged. During the charging process, if an abnormal state of the battery is detected, such as too large internal resistance or too high voltage, the charging will be turned off and disconnected until the state returns to normal.

[0050] Reference Figure 1 In some embodiments, the impedance detection module at least includes an alternating current injection end, an alternating voltage feedback end, an alternating resistance calculation end,

[0051] The alternating current injection end is used for injecting an alternating current signal with a frequency of 20KHz and an amplitude of 1A into the battery pack.

[0052] The alternating voltage feedback end is used for collecting an alternating voltage signal fed back by the battery.

[0053] The alternating resistance calculation end is used for calculating an alternating internal resistance value of the battery according to the alternating current signal and the alternating voltage signal.

[0054] Specifically, the alternating current injection end is a B+ terminal and a B- terminal. The B+ terminal and the B- terminal are battery pack interfaces and are also excitation signal output interfaces during internal resistance detection. The B+ terminal is a positive terminal of the battery pack, and the B- terminal is a negative terminal of the battery pack. The alternating voltage feedback end is a sampling+ terminal and a sampling- terminal. The sampling+ terminal and the sampling- terminal are internal resistance sampling interfaces of the battery pack. In actual application, the sampling+ and the sampling- need to be connected as close to the battery pack as possible. The collection resolution of the internal resistance is 0.1 , the collection accuracy is ±0.5 , and the rated ampere-hour number of the battery is 20AH. The rated ampere-hour number of the battery can be set by the upper computer, which is not limited to 20AH.

[0055] As Figure 3 ​​​​​​In the embodiment, the current detection module at least includes a current detection resistor, a proportional amplifier and a single-chip microcomputer, the current detection resistor is connected with the input end of the proportional amplifier, the single-chip microcomputer is connected with the output end of the proportional amplifier, the current detection resistor is used for converting a current signal into a voltage signal, the proportional amplifier is used for amplifying the voltage signal, and the single-chip microcomputer is used for collecting the voltage signal to detect the charging current in the charging circuit.

[0056] As Figure 4 In some more specific embodiments, the current detection module at least includes a Hall sensor, a proportional amplifier and a single-chip microcomputer, the Hall sensor is connected with the input end of the proportional amplifier, the single-chip microcomputer is connected with the output end of the proportional amplifier, the Hall sensor is used for converting a current signal into a voltage signal, the proportional amplifier is used for amplifying the voltage signal, and the single-chip microcomputer is used for collecting the voltage signal to detect the charging current in the charging circuit.

[0057] The charging current is crucial for the safety of the battery, and too fast charging will cause the diffusion speed of lithium ions in the lithium battery to be unable to keep up with the diffusion speed of electrons, resulting in disconnection of the electrons and ions, abnormal reaction and crystallization. Moreover, if the charging speed exceeds the tolerance of the battery during charging, the internal resistance of the lithium battery will increase, thereby causing the battery to generate excessive temperature and be dangerous.

[0058] Specifically, the current acquisition resolution of the current detection unit is 0.1 A, the acquisition accuracy is ±0.5 A, and the maximum detection current is 30 A. The charging current of the battery can be detected by the current detection unit, and the charging capacity of the battery can be calculated. When the charging current exceeds the preset current threshold, the main control chip can cut off the charging of the battery through the charging control circuit.

[0059] In the embodiment, the voltage detection module at least includes an ADC converter for detecting the battery voltage.

[0060] Battery overcharging is a phenomenon during the charging process of an electric bicycle, especially lithium battery overcharging. Therefore, it is necessary to detect the charging voltage of the battery to determine whether the battery is overcharged. Lithium battery overcharging refers to that the charging voltage of the lithium battery exceeds the maximum cutoff voltage of the lithium battery during the charging process. When overcharged, the battery will generate heat, including ohmic heat and heat generated by side reactions. The heat may trigger the side reactions of the battery, causing the structure of the positive electrode material inside the battery to change and resulting in total capacity loss of the battery. Overcharging will also promote the decomposition of the electrolyte and generate gas (such as hydrogen and oxygen), increase the internal pressure of the battery, and may cause the battery to swell, leak or the shell to rupture to a certain extent.

[0061] Specifically, the battery voltage range is 20–100V, supporting battery voltage platforms of 36V, 48V, 60V, and 72V. The voltage acquisition resolution is 15mV, the acquisition accuracy is ±5mV, and the maximum detection voltage is 100V.

[0062] In this embodiment, the battery safety screening device based on EIS further includes a main control chip. The main control chip is connected to the charging control module, the impedance detection module, the current detection module, and the voltage detection module. The main control chip includes a status display area, a battery information setting area, a threshold setting area, and a calculation area.

[0063] The status display area is used to display the voltage of the battery pack, the charging current in the charging circuit, and the AC impedance of the battery pack.

[0064] The battery information setting area is used to set the rated capacity and voltage platform of the battery pack;

[0065] The threshold setting area is used to preset battery thresholds, which include voltage threshold, charging current threshold, internal resistance threshold, and AC impedance threshold.

[0066] The calculation area is used to calculate the AC impedance and to match the voltage of the battery pack, the charging current in the charging circuit, the AC impedance of the battery pack with the battery threshold to obtain the battery fault detection result.

[0067] Specifically, the calculation area can calculate the AC impedance based on the battery's rated capacity and voltage platform. The threshold setting area is used to set alarm protection thresholds, including voltage threshold, charging current threshold, internal resistance threshold, and AC impedance threshold. Specific threshold settings can be pre-set based on the battery type compatible with the charging pile, or the charging pile can dynamically adjust parameters via an RS485 interface to the safety rapid screening module, or they can be set using a dedicated host computer configuration tool (0 communication instructions). For example, the voltage threshold can be set to 100V; the charging current threshold can be set to 10A; the internal resistance threshold can be set to 100mΩ; and the specific internal resistivity threshold can be set to 60. Ah / V. The rated capacity of the battery can be understood as its rated ampere-hours, which can be set to 20AH. The battery information setting area is also used to set the battery's operating temperature and operating humidity. Specifically, the operating temperature can be set to -30 to 5℃, and the operating humidity can be set to ≤85%RH.

[0068] Preferably, the main control chip also includes an application button, a cancel button, and a factory reset button.

[0069] The apply button is used to write the set parameters to the master chip. The cancel button is used for the configuration tool to exit and the modified parameters will not be written to the master chip. The restore factory settings button is used to restore all parameters to the default values at the factory settings, and the apply button needs to be clicked again if you want to write to the module.

[0070] Specifically, the master control chip is mainly composed of an MCU (Micro Control Unit), which can be called a single-chip microcomputer, and a program code to realize data processing and logical control of the entire device and control the work of the entire system. The master control chip can use an AFE (Analog Front End) chip. On the one hand, the AFE chip can measure some characteristics of the battery, such as the temperature, voltage, current, and voltage of the battery. On the other hand, with respect to the battery interior, the AFE chip can measure the changes in the electrochemical reaction inside the battery through alternating impedance to more truly reflect the battery situation. This dimension of thermal runaway management is the optimal runaway management.

[0071] The AFE chip at least includes temperature monitoring, impedance monitoring, voltage monitoring, communication, and equalization.

[0072] With respect to temperature monitoring, each AFE chip integrates a temperature monitoring sensor, without the need for an external temperature sensor, i.e., without the need for a thermistor or any peripheral device. Two temperature sensors are integrated in one chip for redundancy design. In addition, the wire harness and temperature sensor can also be omitted in the entire battery management system module, which can save the entire structure and save the setting space of the structure. The exposed module pad ensures good thermal coupling of the chip to the battery cell. The temperature is monitored, and a warning is issued when the temperature is too high or too low. With respect to impedance monitoring, the AFE chip can output the real part and the imaginary part of the impedance, which can be used in any working environment. In any working environment, such as driving, static, and charging, the impedance value can be measured, supporting the implementation of multiple advanced system applications. The data update rate is -1 Hz. The AFE chip has a wide range of selectable frequencies, high signal-to-noise ratio, and can measure ultra-low resistance battery cells. The communication part uses a differential I / O chain with a ring topology, which is relatively stable and can be expanded to a maximum of 250 chips. It can be configured as an SPI differential I / O bridge chip, and the communication between chips on the same circuit board is DC coupled. The electromagnetic compatibility design is relatively reliable. The equalization part supports external equalization and also supports internal equalization. The external equalization shares the peripheral devices of the impedance monitoring, with fewer devices and without the need for additional semiconductor devices. The on-chip equalization does not require peripheral devices, and the current of the on-chip equalization can be adjusted. The time-triggered equalization termination and the voltage-triggered equalization termination can read the equalization timeout counter value.

[0073] In this embodiment, the master chip includes an SPI interface for receiving battery safety data. The master chip also includes an RS485 interface for uploading the battery safety data to an upper computer or a cloud monitoring platform.

[0074] When setting the RS485 parameters, the COM number connected to the computer can be selected, the baud rate of the RS485 can be set, the data bits are 8 bits by default, the stop bits are 1 bit by default, and the parity bits are None by default. Specifically, the RS485 interface is used for communication with the upper computer or the cloud monitoring platform, the default baud rate is 9600 bps, the communication protocol is Modbus RTU by default, and it can be used for program upgrading, data uploading, parameter setting, data calibration, charging pile control command, etc. Among them, the baud rate can be set by the upper computer. Data uploading, i.e. uploading battery voltage, battery resistance, battery specific resistance rate and charging current data to the upper computer or the cloud monitoring platform, for real-time data monitoring and recording and later analysis.

[0075] In this embodiment, the alarm module includes at least a sound alarm and an alarm light, the sound alarm is used to issue a warning sound when the battery fault detection result is abnormal, and the alarm light is used to issue a warning light when the battery fault detection result is abnormal. In this way, personnel can be reminded to handle the exception in time, and the risk of losing control can be avoided.

[0076] Specifically, the alarm can be a buzzer. When the battery fault detection result is abnormal, i.e. one or more of the voltage, resistance, specific resistance rate and charging current data exceeds the corresponding preset threshold, the buzzer emits a sound. The indicator light includes two LED lights of different colors, green and red, respectively, for indicating normal and abnormal states. Specifically, green can represent a normal state and red can represent an abnormal state. When the battery fault detection result is abnormal, i.e. one or more of the voltage, resistance, specific resistance rate and charging current data exceeds the corresponding preset threshold, the alarm light displays red.

[0077] For example, the preset resistance threshold of the battery can be set to 60 When it is detected that the battery resistance exceeds 60 , the buzzer emits a sound and the alarm light displays red.

[0078] In the embodiment, the charging control module is connected with the master control chip, and is used for cutting off the circuit when the battery fault detection result is abnormal; the charging control module at least comprises a first charging circuit and a second charging circuit, the first charging circuit is connected with the second charging circuit, the first charging circuit is used for pre-charging the battery, and the first charging circuit at least comprises a series resistor, which is used for limiting the charging current, and the second charging circuit is used for mainly charging the battery. In the initial charging stage of the battery, the current intensity is significantly increased, and therefore the pre-charging strategy must be implemented to avoid potential damage caused by the instantaneous high current.

[0079] Specifically, the charging control can be realized by a MOSFET or a relay.

[0080] The communication circuit of the application comprises two parts of circuits, one part is an RS485, which is used for communicating with external equipment or communicating with an upper computer; and the other part is an SPI interface, which is used for communicating with the internal resistance detection part circuit, controlling the injection time and injection frequency of the alternating current signal, and reading the battery alternating current internal resistance value collected.

[0081] Reference Figure 1 In some embodiments, the EIS-based battery safety screening device further comprises a power supply module, the power supply module comprising a first output power supply and a second output power supply;

[0082] The first output power supply is used for filtering and step-down converting an externally provided power supply into a voltage required by an internal circuit, and outputting the voltage to a current detection module and a voltage detection module.

[0083] The second output power supply is used for outputting a power supply to an impedance detection module.

[0084] Specifically, the first output power supply is used for filtering and step-down converting an externally provided 9-36V power supply into 5V and 3.3V voltages required by an internal circuit. Exemplarily, the module direct current power supply positive and negative electrode interface has a wide direct current voltage range of 9-36V, and has low requirements on the charging pile and flexible adaptation.

[0085] Exemplarily, Figure 1 The P+ and P- are charging input ends, which can be understood as the second output power supply, and are used for outputting an isolated power supply to the internal resistance detection module to ensure normal and stable work of the internal resistance detection module. The P+ is a positive electrode interface of the charging power supply, and the P- is a negative electrode interface of the charging power supply.

[0086] The battery safety screening device based on EIS supports the anti-reverse connection function, damage risks caused by operation errors during installation and debugging can be reduced, and the battery safety screening device based on EIS specifically comprises a battery monitoring module, a main control chip, a charging control module, an alarm module and an anti-reverse connection structure.

[0087] The battery monitoring module can be used for monitoring battery safety data in real time, and the main control chip is used for judging whether the battery safety data exceeds a preset corresponding threshold value.

[0088] When the battery monitoring module detects the battery voltage, the initial state of the battery is detected first, and is compared with a preset AC resistance threshold value.

[0089] Reference Figure 5 A battery safety screening device based on EIS, and the specific implementation process can be referred to as follows:

[0090] Firstly, each module of the battery safety screening device based on EIS is initialized, and relevant parameters are loaded.

[0091] Secondly, the battery monitoring module is used for detecting the output voltage in real time.

[0092] The B+ terminal and the B- terminal are used for injecting an AC current signal of a certain frequency ,​

[0093] The AC voltage signal fed back by the battery pack is collected through the sampling+ terminal and the sampling- terminal

[0094] The AC current signal The AC voltage signal The AC internal resistance value of the battery is calculated

[0095] The main control chip performs filtering and mathematical calculation processing according to the AC internal resistance value to obtain the AC impedance value of the battery.

[0096] In the third step, the main control chip compares the impedance of the battery pack with the impedance threshold value to determine whether the current battery pack meets the battery pack compliance requirements. When the battery pack meets the battery pack compliance requirements, the battery pack starts charging. During the charging process, the main control chip detects the charging current, the charging voltage and the battery pack impedance in real time. If the battery pack always meets the battery pack compliance requirements, the battery pack charges until the charging is completed. During the charging process, if it is found that the impedance does not meet the compliance requirements, that is, an abnormality occurs. At this time, the charging control module is powered off, and the battery pack charging is interrupted. Subsequently, the alarm module starts alarming. At this time, the abnormal battery pack needs to be removed from the circuit. When the output end voltage is less than the voltage threshold value, it is considered that the battery pack has been removed. When the battery pack is connected again, the first step to the third step are repeated until the charging is completed.

[0097] When the battery pack does not meet the battery pack compliance requirements, the battery pack does not charge. The alarm module starts alarming. At this time, the abnormal battery pack needs to be removed from the circuit. When the output end voltage is less than the voltage threshold value, it is considered that the battery pack has been removed. When the battery pack is connected again, the first step to the third step are repeated until the charging is completed.

[0098] In summary, the battery safety screening device based on EIS can track the dynamic changes of the internal electrochemical reaction of the battery in real time, thereby more accurately reflecting the aging state of the battery, and has high safety and high efficiency of electrical performance management. In addition, the present scheme also relates to calculating the internal resistance of the vehicle-mounted lithium battery by using a steady-state current, and comparing the calculation result with a preset standard threshold value to determine the internal resistance fault of the vehicle-mounted lithium battery. The device mainly utilizes the battery management system (BMS) built in the 12V low-voltage lithium battery to construct a vehicle-mounted lithium battery internal resistance fault detection system, and evaluates the health status of the battery through the AC internal resistance.

[0099] The utility model embodiment further provides a charging pile, the charging pile is provided with the battery safety screening device based on EIS.

[0100] ​​The utility model discloses an EIS-based battery safety screening device and a mobile electric equipment.

[0101] It should be noted that the screening device disclosed by the utility model should be well prepared for the corresponding anti-static measures when testing, installing, using and contacting. When using a higher DC voltage than the maximum bearable DC voltage, damage is easy to occur. When wiring, the positive and negative terminals and the corresponding battery pack and charging pile direction need to be paid attention to, and a good heat dissipation environment is needed to prevent heat accumulation from causing accidents.

[0102] It should be understood that the above embodiments are only for illustrating the technical concept and characteristics of the utility model, and the purpose is to enable persons skilled in the art to understand the content of the utility model and implement it, and it cannot limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit and essence of the utility model should be covered within the protection scope of the utility model.

Claims

1. An EIS-based battery safety screening device for a battery pack electrically connected to a charging post and an electrical device, the device comprising: The battery safety screening device comprises: A charging control module connected in series with the charging pile and the battery pack and used for turning on or off the charging circuit of the charging pile and the battery pack; An impedance detection module electrically connected with the positive and negative terminals of the battery pack and used for collecting a perturbation signal of the positive and negative terminals of the battery pack and analyzing the AC impedance of the battery pack based on the perturbation signal; A current detection module connected in series with the charging pile and the battery pack and used for detecting the charging current in the charging circuit; A voltage detection module connected in parallel with the battery pack and used for detecting the voltage of the battery pack.

2. The EIS-based battery safety screening device of claim 1, wherein, The current detection module at least comprises a current detection resistor, a proportional amplifier and a single-chip microcomputer, the current detection resistor is connected with the input end of the proportional amplifier, the single-chip microcomputer is connected with the output end of the proportional amplifier, the current detection resistor is used for converting the current signal into a voltage signal, the proportional amplifier is used for amplifying the voltage signal, and the single-chip microcomputer is used for collecting the voltage signal to detect the charging current in the charging circuit.

3. The EIS-based battery safety screening device of claim 1, wherein, The current detection module at least comprises a Hall sensor, a proportional amplifier and a single-chip microcomputer, the Hall sensor is connected with the input end of the proportional amplifier, the single-chip microcomputer is connected with the output end of the proportional amplifier, the Hall sensor is used for converting the current signal into a voltage signal, the proportional amplifier is used for amplifying the voltage signal, and the single-chip microcomputer is used for collecting the voltage signal to detect the charging current in the charging circuit. And / or, the voltage detection module at least comprises an ADC converter.

4. The EIS-based battery safety screening device of claim 1, wherein, The impedance detection module at least comprises an AC current injection end, an AC voltage feedback end and an AC resistance calculation end, The alternating current injection end is used for injecting an alternating current signal with a frequency of into the battery pack . The alternating voltage feedback end is used for collecting the alternating voltage signal fed back by the battery , The AC resistance calculation terminal is used to calculate the AC current signal. AC voltage signal Calculate the AC internal resistance of the battery. .

5. The EIS-based battery safety screening device of claim 1, wherein, Further comprising a master control chip connected with the charging control module, the impedance detection module, the current detection module and the voltage detection module, the master control chip comprises a state display area, a battery information setting area, a threshold setting area and a calculation area, The state display area is used for displaying the voltage of the battery pack, the charging current in the charging circuit and the AC impedance of the battery pack. The battery information setting area is used for setting the rated capacity and voltage platform of the battery pack. The threshold setting area is used for presetting a battery threshold, and the battery threshold comprises a voltage threshold, a charging current threshold, an internal resistance threshold and an AC impedance threshold. The calculation area is used for calculating the AC impedance and matching the voltage of the battery pack, the charging current in the charging circuit and the AC impedance of the battery pack with the battery threshold to obtain a battery fault detection result.

6. The EIS-based battery safety screening device of claim 5, wherein, Further comprising an alarm module at least comprising a sound alarm and / or an alarm lamp, the sound alarm is used for emitting a warning sound when the battery fault detection result is abnormal, and the alarm lamp is used for emitting a warning light when the battery fault detection result is abnormal.

7. The EIS-based battery safety screening device of claim 5, wherein, The charging control module is connected with the master control chip, and is used for cutting off the circuit when the battery fault detection result is abnormal; the charging control module at least includes a first charging circuit and a second charging circuit; the first charging circuit is connected with the second charging circuit; the first charging circuit is used for pre-charging the battery; the first charging circuit at least includes a series resistor, which is used for limiting the charging current; and the second charging circuit is used for mainly charging the battery.

8. The EIS-based battery safety screening device of claim 1, wherein, Further comprising a power module, the power module includes a first output power supply, a second output power supply; The first output power supply is used for filtering and step-down of the externally provided power supply, converting into the voltage required by the internal circuit, and outputting to the current detection module and the voltage detection module; The second output power supply is used for outputting the power supply to the impedance detection module.

9. A charging post, characterized by: The charging pile is provided with the EIS-based battery safety screening device according to claims 1-8.

10. A mobile electric device, characterized by The mobile electric equipment is provided with the EIS-based battery safety screening device according to claims 1-8.

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