An on-line detection device and detection method for the health of a vehicle battery

Abstract

The present invention discloses an on-line detection device for the health of a vehicle battery, characterized in that: it includes a detection host, a detection signal transmission line and a detection signal reception line. The detection host has a signal output port and a signal input port. The detection host is used to generate and output alternating current signals of different frequencies through its signal output port. One end of the detection signal transmission line is connected to the signal output port of the detection host, and the positive electrode of each battery cell is connected to the detection signal transmission line through a first jumper wire. A first blocking module is installed on the first jumper wire. One end of the detection signal reception line is connected to the signal input port of the detection host, and the negative electrode of each battery cell is connected to the detection signal reception line through a second jumper wire. A second blocking module is installed on the second jumper wire. Both the first blocking module and the second blocking module are used to block the direct current signal flowing through the jumper wire and allow alternating current signals in a certain frequency band to flow through the jumper wire.

Description

Technical Field

[0001] The present invention relates to the technical field of battery detection, and more specifically, it relates to an on-line detection device and method for the health of vehicle batteries. Background Art

[0002] With the increasing prominence of energy issues and the growing popularity of environmental awareness, more and more automobile manufacturers are gradually shifting from the traditional fuel vehicle front to the new energy vehicle front.

[0003] Electric vehicles are increasingly favored by car owners due to their unique advantages such as low usage cost, quiet driving comfort, and government policy subsidies.

[0004] Currently, the driving range, driving range stability, and charging convenience are the biggest obstacles restricting the popularization of electric vehicles. The battery driving range of electric vehicles is not only affected by temperature but also directly affected by the battery health. After the battery health deteriorates, its capacity and conductivity will also decrease.

[0005] In the prior art, the detection of battery health is generally achieved by measuring the conductivity of the battery, that is, a detection signal is input at the positive electrode of the battery, and the detection signal will flow out from the negative electrode of the battery. The intensity of the detection signal output from the battery is compared and calculated with the intensity of the detection signal output by the battery. The lower the conductivity, the more serious the signal attenuation. The battery health is indirectly judged by the attenuation degree of the detection signal.

[0006] For electric vehicles equipped with dozens or even hundreds of batteries, since the batteries are connected in series, when the health of one battery significantly deteriorates, it will have an adverse impact on the discharge and charging performance of the entire battery pack, resulting in a decline in the overall performance of the battery pack.

[0007] To save the cost of replacing the battery, when the health of a certain battery in the battery pack deteriorates rapidly, it needs to be replaced separately.

[0008] However, the traditional detection method is only applicable to single batteries and cannot quickly locate a battery cell with severely deteriorated health in the battery pack, resulting in the need to manually test each battery cell to find the battery cell and then replace it, which is time-consuming, laborious, and inefficient and needs to be improved. Summary of the Invention

[0009] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an on-line monitoring device and detection method for the health of vehicle batteries, which can quickly locate the battery cells with severely deteriorated health in the vehicle battery pack.

[0010] To achieve the above purpose, the present invention provides the following technical solutions:

[0011] An on-line detection device for the health of vehicle batteries, comprising a detection host, a detection signal transmission line and a detection signal reception line. The detection host has a signal output port and a signal input port. The detection host is used to generate and output alternating current signals of different frequencies through its signal output port. One end of the detection signal transmission line is connected to the signal output port of the detection host, and the positive electrodes of each battery cell are connected to the detection signal transmission line through a first jumper wire. A first blocking module is installed on the first jumper wire. One end of the detection signal reception line is connected to the signal input port of the detection host, and the negative electrodes of each battery cell are connected to the detection signal reception line through a second jumper wire. A second blocking module is installed on the second jumper wire. Both the first blocking module and the second blocking module are used to block the direct current signal flowing through the jumper wire and allow alternating current signals in a certain frequency band to flow through the jumper wire. The first blocking module and the second blocking module corresponding to each battery cell have the same filtering frequency band, and the filtering frequency bands of the first blocking module and the second blocking module corresponding to each group of battery cells increase sequentially along the arrangement direction of the battery cells. The detection host sequentially generates and outputs alternating current signals with the same frequency as the filtering frequency band of the blocking module of each battery cell to the detection signal transmission line, and receives the alternating current signals fed back by the detection signal reception line. The detection host compares the intensity value of the transmitted alternating current signal with the intensity value of the received alternating current signal, calculates the difference between the two, and compares the difference with a preset alarm value. When the former is greater than the latter, the detection host generates a warning message containing the identification number of the battery cell and uploads the warning message to the on-line detection platform.

[0012] As a preferred solution: It further includes a voltage acquisition circuit. One end of the voltage acquisition circuit is connected to the positive electrode of the battery pack, and the other end of the voltage acquisition circuit is connected to the voltage sampling port of the detection host.

[0013] As a preferred solution: Both the first blocking module and the second blocking module include a switch unit and a blocking unit. The blocking unit is used to block the direct current signal flowing through the jumper wire and allow alternating current signals in a certain frequency band to flow through the jumper wire. The switch unit is connected in parallel with the blocking unit, and the switch unit is connected to the detection host and controlled by the detection host.

[0014] As a preferred solution: The switch unit is a switch circuit composed of triodes.

[0015] As a preferred solution: The detection host includes a main control module, a D / A conversion module, a signal amplification circuit, a communication module, a storage module, and a power supply module. Among them, the main control module is an MCU module. The input end of the D / A conversion module is connected to the PWM signal output end of the main control module, and the output end of the D / A conversion module is connected to the detection signal transmission line. The D / A conversion module is used to convert the PWM signal into an AC analog signal. The input end of the signal amplification circuit is connected to the detection signal receiving line, and the output end of the signal amplification circuit is connected to the I / O port of the main control module. The communication module is connected to the communication port of the main control module. The power supply module is used to supply power to the entire detection device.

[0016] An on-line detection method for the health of vehicle batteries includes the following steps:

[0017] S1. Lay the detection signal transmission line and the detection signal receiving line along the arrangement direction of the battery cells. Connect the positive electrode of each battery cell to the detection signal transmission line through the first jumper wire, and connect the negative electrode of each battery cell to the detection signal receiving line through the second jumper wire. Install a first blocking module and a second blocking module on the first jumper wire and the second jumper wire respectively, which are used to block DC signals and allow AC signals in a certain frequency band to pass through. The first blocking module and the second blocking module corresponding to each battery cell have the same filtering frequency band, and along the arrangement direction of the battery cells, the filtering frequency bands of the first blocking module and the second blocking module corresponding to each group of battery cells increase sequentially.

[0018] S2. The detection host sequentially sends AC signals with the same frequency as the filtering frequency band of the blocking module of each battery cell to the detection signal transmission line, and receives the AC signals fed back by the detection signal receiving line.

[0019] S3. Compare the intensity of the sent AC signal with the intensity of the received AC signal, calculate the difference between the two, and compare the difference with a preset alarm value. When the former is greater than the latter, the detection host generates a warning message containing the identification number of the battery cell, and uploads the warning message to the on-line detection platform.

[0020] As a preferred solution, the S3 step further includes a step of secondary confirmation of the health of the battery cell, specifically: judge whether the battery pack is in a charging or discharging state by collecting the terminal voltage of the battery pack, and detect each battery cell in both the charging and discharging states, and compare the detection results in the two states. When the detection results of a certain battery cell in the two states are both severe decline in health, it is considered that the health of the battery cell is insufficient and needs to be replaced.

[0021] Compared with the prior art, the advantages of the present invention are as follows: The detection device can automatically and quickly detect the health status of all battery cells in the battery pack, and can quickly locate the battery cells with relatively serious health degradation, enabling maintenance personnel to find the battery cells in the first time and replace them, saving time and effort, and greatly improving the efficiency of battery detection and maintenance. Description of the Drawings

[0022] Figure 1 It is a wiring schematic diagram of the detection device in Embodiment 1;

[0023] Figure 2 is Figure 1 the enlarged view of part A in

[0024] Figure 3 It is a schematic diagram of the principle of the barrier module in Embodiment 1;

[0025] Figure 4 It is a circuit block diagram of the detection host in Embodiment 1;

[0026] Figure 5 It is a schematic diagram of the layer structure of the cable in Embodiment 1.

[0027] Description of the reference numerals: 1, battery cell; 2, positive electrode; 3, negative electrode; 4, wire; 5, detection host; 6, detection signal transmission line; 7, detection signal reception line; 8, first jumper; 9, second jumper; 10, first barrier module; 11, second barrier module; 12, current-limiting resistor; 13, cable; 14, first insulating layer; 15, aluminum foil layer; 16, second insulating layer; 17, braided copper mesh layer; 18, insulating outer skin. Detailed Embodiment

[0028] Embodiment 1:

[0029] Referring to Figure 1 and Figure 2 , an on-line detection device for the health status of vehicle batteries includes a detection host 5, a detection signal transmission line 6 and a detection signal reception line 7.

[0030] Among them, the detection host 5 has a signal output port and a signal input port. The detection host 5 is used to generate and output alternating current signals of different frequencies through its signal output port. One end of the detection signal transmission line 6 is connected to the signal output port of the detection host 5. The positive electrode 2 of each battery cell 1 is connected to the detection signal transmission line 6 through the first jumper 8. A first barrier module 10 is installed on the first jumper 8. One end of the detection signal reception line 7 is connected to the signal input port of the detection host 5. The negative electrode 3 of each battery cell 1 is connected to the detection signal reception line 7 through the second jumper 9. A second barrier module 11 is installed on the second jumper 9.

[0031] The first blocking module 10 is used to block the DC signal flowing through the first jumper 8 and allow the AC signal of a certain frequency band to flow through the first jumper 8; the second blocking module 11 is used to block the DC signal flowing through the second jumper 9 and allow the AC signal of a certain frequency band to flow through the second jumper 9.

[0032] The blocking module can be a filter circuit composed of components such as capacitors.

[0033] The first blocking module 10 and the second blocking module 11 corresponding to each battery cell 1 have the same filtering frequency band, and the filtering frequency bands of the first blocking module 10 and the second blocking module 11 corresponding to each group of battery cells 1 along the arrangement direction of the battery cells 1 increase sequentially.

[0034] For example, for the battery cell 1D1, the filtering frequency band of its corresponding first blocking module 10 and second blocking module 11 is m1 - m2 Hz (i.e., the first frequency band); for the battery cell 1D2, the filtering frequency band of its corresponding first blocking module 10 and second blocking module 11 is m3 - m4 Hz (i.e., the second frequency band); for the battery cell 1D3, the filtering frequency band of its corresponding first blocking module 10 and second blocking module 11 is m5 - m6 Hz (i.e., the second frequency band) and so on.

[0035] The working principle of this detection device is as follows:

[0036] The detection host 5 sequentially generates AC signals of the first frequency band, the second frequency band... the Nth frequency band. The AC signal of the first frequency band is transmitted from the signal output port to the detection signal transmitting line 6. Since the AC signal of the first frequency band can only flow through the first blocking module 10 and the second blocking module 11, the AC signal of the first frequency band first flows from the detection signal transmitting line 6 into the positive electrode 2 of the battery cell 1D1 through the first jumper 8, then flows out from the negative electrode 3 of the battery cell 1D1, then flows out from the second jumper 9 to the detection signal receiving line 7, and finally flows back to the signal input port of the detection host 5.

[0037] The detection host 5 compares the intensity value of the transmitted AC signal with the intensity value of the received AC signal, calculates the difference between the two, and compares the difference with a preset alarm value. When the former is greater than the latter, the detection host 5 generates a warning message containing the identification number of the battery cell 1 and uploads the warning message to the online detection platform.

[0038] After completing the above steps, the detection host 5 subsequently transmits AC signals of the second frequency band, the third frequency band... the Nth frequency band in sequence until the automatic detection of all battery cells 1 is completed.

[0039] Through the above technical solution, the health of all battery cells 1 in the battery pack can be automatically and quickly detected, and the battery cells 1 with severely deteriorated health can be quickly located, enabling maintenance personnel to find and replace the battery cells 1 in the first time, saving time and effort and greatly improving the efficiency of battery detection and maintenance.

[0040] Referring to Figure 4 , the detection host 5 in this embodiment includes a main control module, a D / A conversion module, a signal amplification circuit, a communication module, a storage module, and a power supply module.

[0041] Among them, the main control module is an MCU module. The input end of the D / A conversion module is connected to the PWM signal output end of the main control module, and the output end of the D / A conversion module is connected to the detection signal transmission line 6. The D / A conversion module is used to convert the PWM signal into an AC analog signal. The input end of the signal amplification circuit is connected to the detection signal receiving line 7, and the output end of the signal amplification circuit is connected to the I / O end of the main control module. The function of the signal amplification circuit is to amplify the relatively weak AC signal so that the main control module can recognize the AC signal. After the main control module recognizes the AC signal, it restores the AC signal according to the amplification factor of the signal amplification circuit, and then calculates the actual signal strength of the AC signal. In this way, it can ensure that the detection of a certain battery cell 1 can be successfully completed even when it is severely damaged. The communication module is connected to the communication port of the main control module and is used for communication between the main control module and the online detection platform. The power supply module is used to supply power to the entire detection device.

[0042] In this embodiment, the detection host 5 further includes a voltage acquisition circuit. One end of the voltage acquisition circuit is connected to the positive electrode 2 of the entire battery pack, and the other end is connected to the sampling port of the main control module.

[0043] By collecting the voltage of the positive electrode 2 of the battery pack, it is judged whether the battery pack is in a charging or discharging state. When the battery pack is charging, the voltage of its positive electrode 2 is stable at the charging voltage. When the battery pack is discharging, the voltage of its positive electrode 2 will gradually decrease. Therefore, it is judged whether the battery pack is in a charging or discharging state according to the collected voltage.

[0044] In this embodiment, the detection host 5 performs a detection on all the battery cells 1 in the entire battery pack both in the charging state and the discharging state, and compares the detection results in the two states. When the detection results of a certain battery cell 1 in the two states are both severely deteriorated in health, it is considered that the health of the battery cell 1 is insufficient and needs to be replaced. In this way, the interference of the charge and discharge state on the detection result can be eliminated, and the accuracy of the detection can be improved.

[0045] Such as Figure 1As shown, a current-limiting resistor 12 is installed on the voltage acquisition circuit. The resistance value of the current-limiting resistor 12 is much larger than the impedance of the entire battery pack, so that when the battery pack is in the charging state, no excessive current will flow through the voltage acquisition circuit to the main control module, thereby protecting the detection host 5.

[0046] Referring to Figure 3 , in this embodiment, both the first barrier module 10 and the second barrier module 11 include a switch unit and a barrier unit. The barrier unit is used to block the DC signal flowing through the jumper and allow an AC signal in a certain frequency band to flow through the jumper. The switch unit is connected in parallel with the barrier unit, and the switch unit is connected to the I / O terminal of the main control module and is controlled by the main control module.

[0047] In the initial state, the switch unit is in the off state, and the barrier module only allows AC signals to pass through; when the main control module sends a level signal to the switch unit, the switch unit becomes conductive, and at this time the barrier module can allow DC signals to pass through.

[0048] The switch unit can be a switch circuit composed of triodes.

[0049] After the detection host 5 conducts the first detection on the overall battery pack, if it detects that the battery pack is in a charging state, the main control module controls the first isolation module 10 and the second isolation module 11 corresponding to the target battery cell 1 (the target battery cell 1 is the battery cell 1 with a serious attenuation of health detected in the first detection) according to the results of the first detection, so that the switching units of the first isolation module 10 and the second isolation module 11 both change from the off state to the on state. At this time, direct current passes from the positive electrode 2 of the target battery cell 1 to the detection signal transmitting line 6 through the first jumper 8, and direct current passes from the negative electrode 3 of the target battery cell 1 to the detection signal receiving line 7 through the second jumper 9. The main control module obtains the terminal voltage of the target battery cell 1 by subtracting the voltage of the negative electrode 3 from the voltage of the positive electrode 2 of the target battery cell 1; the main control module then controls the first isolation module 10 and the second isolation module 11 corresponding to a non-target battery cell 1 (the non-target battery cell 1 is the battery cell 1 with normal health detected in the first detection), so that the switching units of the corresponding first isolation module 10 and second isolation module 11 both change from the off state to the on state. At this time, direct current passes from the positive electrode 2 of the non-target battery cell 1 to the detection signal transmitting line 6 through the first jumper 8, and direct current passes from the negative electrode 3 of the non-target battery cell 1 to the detection signal receiving line 7 through the second jumper 9. The main control module obtains the terminal voltage of the non-target battery cell 1 by subtracting the voltage of the negative electrode 3 from the voltage of the positive electrode 2 of the non-target battery cell 1; then the main control module compares the increment of the terminal voltage of the target battery cell 1 collected in the previous and current times with the increment of the terminal voltage of the non-target battery cell 1 collected in the previous and current times. When the former is less than the latter and the difference between the two is greater than the preset value, it is determined that the health of the target battery cell 1 is insufficient and needs to be replaced in time. At this time, the detection host 5 generates a warning message containing the identification number of the target battery cell 1 and uploads the warning message to the online detection platform.

[0050] For the battery cell 1 with damaged health, at the same charging voltage, the terminal voltage of the normal battery cell 1 rises faster, while the terminal voltage of the battery cell 1 with insufficient health rises very slowly or even stops rising, resulting in the situation that it cannot be fully charged.

[0051] Through the above means, all battery cells 1 in the battery pack can be subjected to preliminary inspection and secondary detection confirmation, and the detection accuracy can be improved through double detection.

[0052] Since the switching state of the isolation module for the DC signal can be changed, there is no need to additionally wire to squeeze the terminal voltage of the battery cell 1, which can simplify the wiring, reduce costs, and be more flexible to use.

[0053] Refer to Figure 5, in this embodiment, both the detection signal transmitting line 6 and the detection signal receiving line 7 are of a multi-layer structure, which sequentially includes a cable 13, a first insulating layer 14, an aluminum foil layer 15, a second insulating layer 16, a braided copper mesh layer 17, and an insulating outer skin 18 from the inside out. Such a structure can not only effectively protect the cable 13 but also enable the wire material to have good electromagnetic shielding performance, avoiding electromagnetic interference of alternating current signals on the battery cell 1 and ensuring the stable operation of the overall battery pack.

[0054] Embodiment Two:

[0055] A detection method applicable to the detection device in Embodiment One includes the following steps:

[0056] S1. Lay the detection signal transmitting line and the detection signal receiving line along the arrangement direction of the battery cells. Connect the positive electrodes of each battery cell to the detection signal transmitting line through the first jumper wire, and connect the negative electrodes of each battery cell to the detection signal receiving line through the second jumper wire. Install a first blocking module and a second blocking module on the first jumper wire and the second jumper wire respectively, which are used to block direct current signals and allow alternating current signals in a certain frequency band to pass through. The first blocking module and the second blocking module corresponding to each battery cell have the same filtering frequency band, and the filtering frequency bands of the first blocking module and the second blocking module corresponding to each group of battery cells along the arrangement direction of the battery cells increase sequentially;

[0057] S2. The detection host sequentially sends alternating current signals with the same frequency as the filtering frequency band of the blocking module of each battery cell to the detection signal transmitting line, and receives the alternating current signals fed back by the detection signal receiving line;

[0058] S3. Compare the intensity of the sent alternating current signal with the intensity of the received alternating current signal, calculate the difference between the two, and compare the difference with a preset alarm value. When the former is greater than the latter, the detection host generates a warning message containing the identification number of the battery cell and uploads the warning message to the online detection platform.

[0059] In this embodiment, the S3 step further includes a step of secondarily confirming the health of the battery cell, specifically: judging whether the battery pack is in a charging or discharging state by collecting the terminal voltage of the battery pack, detecting each battery cell in both the charging and discharging states, and comparing the detection results in the two states. When the detection results of a certain battery cell in the two states both show a serious decline in health, it is considered that the health of the battery cell is insufficient and needs to be replaced.

[0060] Another method for secondary confirmation of battery health is as follows: both the first barrier module and the second barrier module include a switch unit and a barrier unit. The switch unit is connected in parallel with the barrier unit. After a complete detection of the entire battery pack, when it is detected that the battery pack is in a charging state, the switch unit of the barrier module of the target battery cell is controlled to change from the off state to the on state, and the terminal voltage of the target battery cell is collected through the first jumper and the second jumper. Also, the switch unit of the barrier module of the non-target battery cell is controlled to change from the off state to the on state, and the terminal voltage of the non-target battery cell is collected through the first jumper and the second jumper. The increment of the terminal voltage collected twice for the target battery cell is compared with the increment of the terminal voltage collected twice for the non-target battery cell. When the former is less than the latter and the difference between the two is greater than a preset value, it is determined that the health of the target battery cell is insufficient and needs to be replaced in time.

[0061] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. An on-line detection device for the health of vehicle batteries, Characterized in that: It includes a detection host, a detection signal transmission line and a detection signal reception line. The detection host has a signal output port and a signal input port. The detection host is used to generate and output alternating current signals of different frequencies through its signal output port. One end of the detection signal transmission line is connected to the signal output port of the detection host. The positive electrodes of each battery cell are connected to the detection signal transmission line through a first jumper wire. A first blocking module is installed on the first jumper wire. One end of the detection signal reception line is connected to the signal input port of the detection host. The negative electrodes of each battery cell are connected to the detection signal reception line through a second jumper wire. A second blocking module is installed on the second jumper wire. Both the first blocking module and the second blocking module are used to block the direct current signal flowing through the jumper wire and allow alternating current signals in a certain frequency band to flow through the jumper wire. The first blocking module and the second blocking module corresponding to each battery cell have the same filtering frequency band, and along the arrangement direction of the battery cells, the filtering frequency bands of the first blocking module and the second blocking module corresponding to each group of battery cells increase sequentially. The detection host sequentially generates and outputs alternating current signals with the same frequency as the filtering frequency band of the blocking module of each battery cell to the detection signal transmission line, and receives the alternating current signals fed back by the detection signal reception line. The detection host compares the intensity value of the transmitted alternating current signal with the intensity value of the received alternating current signal, calculates the difference between the two, and compares the difference with a preset alarm value. When the former is greater than the latter, the detection host generates a warning message containing the identification number of the battery cell and uploads the warning message to the on-line detection platform.

2. The on-line detection device for the health of vehicle batteries according to claim 1, Characterized in that: It further includes a voltage acquisition circuit. One end of the voltage acquisition circuit is connected to the positive electrode of the battery pack, and the other end of the voltage acquisition circuit is connected to the voltage sampling port of the detection host.

3. The on-line detection device for the health of vehicle batteries according to claim 1, Characterized in that: Both the first blocking module and the second blocking module include a switch unit and a blocking unit. The blocking unit is used to block the direct current signal flowing through the jumper wire and allow alternating current signals in a certain frequency band to flow through the jumper wire. The switch unit is connected in parallel with the blocking unit. The switch unit is connected to the detection host and is controlled by the detection host.

4. The on-line detection device for the health of vehicle batteries according to claim 3, Characterized in that: The switch unit is a switch circuit composed of triodes.

5. The on-line detection device for the health of vehicle batteries according to claim 3, Characterized in that: The detection host includes a main control module, a D / A conversion module, a signal amplification circuit, a communication module, a storage module, and a power supply module. The main control module is an MCU module. The input end of the D / A conversion module is connected to the PWM signal output end of the main control module, and the output end of the D / A conversion module is connected to the detection signal transmission line. The D / A conversion module is used to convert the PWM signal into an AC analog signal. The input end of the signal amplification circuit is connected to the detection signal receiving line, and the output end of the signal amplification circuit is connected to the I / O end of the main control module. The communication module is connected to the communication port of the main control module. The power supply module is used to supply power to the entire detection device.

6. An on-line detection method for the health of a vehicle battery Characterized in that It includes the following steps: S1. Lay a detection signal transmission line and a detection signal receiving line along the arrangement direction of the battery cells. Connect the positive electrode of each battery cell to the detection signal transmission line through a first jumper wire, and connect the negative electrode of each battery cell to the detection signal receiving line through a second jumper wire. Install a first blocking module and a second blocking module on the first jumper wire and the second jumper wire respectively, which are used to block DC signals and allow AC signals in a certain frequency band to pass through. The first blocking module and the second blocking module corresponding to each battery cell have the same filtering frequency band, and the filtering frequency bands of the first blocking module and the second blocking module corresponding to each group of battery cells increase sequentially along the arrangement direction of the battery cells. S2. The detection host sequentially sends AC signals with the same frequency as the filtering frequency band of the blocking module of each battery cell to the detection signal transmission line and receives the AC signals fed back by the detection signal receiving line. S3. Compare the intensity of the sent AC signal with the intensity of the received AC signal, calculate the difference between the two, and compare the difference with a preset alarm value. When the former is greater than the latter, the detection host generates a warning message containing the identification number of the battery cell and uploads the warning message to the on-line detection platform.

7. The detection method according to claim 6 Characterized in that The step S3 further includes a step of secondary confirmation of the health of the battery cell, specifically: judge whether the battery pack is in a charging or discharging state by collecting the terminal voltage of the battery pack, and detect each battery cell in both the charging and discharging states, and compare the detection results in the two states. When the detection results of a certain battery cell in the two states are both serious decline in health, it is considered that the health of the battery cell is insufficient and needs to be replaced.

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