Electrochemical impedance spectroscopy measuring device and control method

Abstract

The invention discloses an electrochemical impedance spectroscopy measuring device and a control method. The electrochemical impedance spectroscopy measuring device comprises a cell selection module, the cell selection module comprises a plurality of switch units, the switch units are connected with cells in a one-to-one correspondence manner, positive electrodes and negative electrodes of the cells are connected with a control module through the switch units, a first end of a driving module is grounded, and a second end of the driving module is connected with the control module; the third end and the fourth end of the driving module are respectively connected with the anode and the cathode of the battery pack, the fifth end of the driving module is connected with the excitation module, and the excitation module is also respectively connected with the anode and the cathode of the battery pack and the control module; the battery cell selection module is used for selecting a tested battery cell; the driving module is used for driving the excitation module; the excitation module is used for generating excitation current; and the control module is used for calculating the electrochemical impedance spectrum of the measured battery cell based on the voltage and the excitation current of the measured battery cell. By adopting the scheme, the measurement cost of the electrochemical impedance spectroscopy of the battery cell can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to an electrochemical impedance spectroscopy measuring device and a control method. Background Art

[0002] EIS (Electrochemical Impedance Spectroscopy) is an analytical technique used to study the frequency response characteristics of electrochemical systems.

[0003] With the rapid development of new energy vehicles, energy storage technologies, and other fields, the requirements for battery performance are becoming increasingly stringent. As a key tool for battery research and performance optimization, EIS will continue to see growing market demand. EIS can describe the impedance characteristics of batteries over a wide frequency range, reflecting information about the electrochemical processes within the battery.

[0004] However, in the prior art, EIS measurements are mostly performed using an electrochemical workstation, which has a complex architecture and a single measurement channel, resulting in a high cost for measuring the electrochemical impedance spectroscopy of a battery cell. Summary of the Invention

[0005] The present invention provides an electrochemical impedance spectroscopy measuring device and a control method to reduce the measurement cost of the electrochemical impedance spectroscopy of a battery cell.

[0006] According to one aspect of the present invention, an electrochemical impedance spectroscopy measuring device is provided, which includes: a cell selection module, a control module, a driving module and an excitation module;

[0007] The cell selection module is connected to the battery pack, and the cells in the battery pack are connected in series. The cell selection module includes a plurality of switch units, and each switch unit is connected to each cell in a one-to-one correspondence. The positive electrode of the cell and the negative electrode of the cell are both connected to the control module through the switch unit. The first end of the drive module is connected to the control module, and the second end of the drive module is grounded. The third and fourth ends of the drive module are respectively connected to the positive and negative electrodes of the battery pack. The fifth end of the drive module is connected to the excitation module. The excitation module is also respectively connected to the positive electrode of the battery pack, the negative electrode of the battery pack and the control module;

[0008] The cell selection module is used to select the cell to be tested; the driving module is used to drive the excitation module; the excitation module is used to generate an excitation current; and the control module is used to calculate the electrochemical impedance spectrum of the cell to be tested based on the voltage of the cell to be tested and the excitation current.

[0009] Optionally, the switch unit includes: a first switch and a second switch;

[0010] The first end of the first switch is connected to the positive electrode of the battery cell, the second end of the first switch is connected to the control module, the second end of the second switch is connected to the negative electrode of the battery cell, and the second end of the second switch is connected to the control module.

[0011] Optionally, the battery cell selection module further includes: a switch control unit;

[0012] Each of the switch units is connected to the switch control unit;

[0013] The switch control unit is used to control the on or off of each of the switch units.

[0014] Optionally, the switch unit includes: a first switch component and a second switch component;

[0015] The first end of the first switch assembly is connected to the positive end of the switch control unit, the second end of the first switch assembly is connected to the negative end of the switch control unit, the third end of the first switch assembly is connected to the negative electrode of the battery cell, the fourth end of the first switch assembly is connected to the positive electrode of the battery cell, the fifth end of the first switch assembly is connected to the control module, the first end of the second switch assembly is connected to the first end of the first switch assembly, the second end of the second switch assembly is connected to the second end of the first switch assembly, the third end of the second switch assembly is connected to the positive electrode of the battery cell, the fourth end of the second switch assembly is connected to the negative electrode of the battery cell, the fifth end of the second switch assembly is connected to the control module, the negative end of the switch control unit is grounded, and the common end of the switch control unit is connected to the negative end of the switch control unit.

[0016] Optionally, the first switch component includes: a first optocoupler, a first switch tube, a second switch tube and a first switch resistor;

[0017] The first end of the light-emitting side of the first optocoupler is connected to the positive end of the switch control unit, the second end of the light-emitting side of the first optocoupler is connected to the negative end of the switch control unit, the first end of the light-receiving side of the first optocoupler is connected to the negative electrode of the battery cell, the second end of the light-receiving side of the first optocoupler is connected to the control end of the first switching tube, the first end of the first switching tube is connected to the positive electrode of the battery cell, the second end of the first switching tube is connected to the first end of the second switching tube, the second end of the second switching tube is connected to the control module, the control end of the second switching tube is connected to the control end of the first switching tube, the first switch resistor is connected between the control end and the second end of the first switching tube, the negative end of the switch control unit is grounded, and the common end of the switch control unit is connected to the negative end of the switch control unit;

[0018] The second switch component includes: a second optocoupler, a third switch tube, a fourth switch tube and a second switch resistor;

[0019] The first end of the light-emitting side of the second optocoupler is connected to the positive end of the switch control unit, the second end of the light-emitting side of the second optocoupler is connected to the negative end of the switch control unit, the first end of the light-receiving side of the second optocoupler is connected to the control end of the third switch tube, the second end of the light-receiving side of the second optocoupler is connected to the positive electrode of the battery cell, the first end of the third switch tube is connected to the negative electrode of the battery cell, the second end of the third switch tube is connected to the first end of the fourth switch tube, the second end of the fourth switch tube is connected to the control module, the control end of the fourth switch tube is connected to the control end of the third switch tube, and the second switch resistor is connected between the control end and the second end of the third switch tube.

[0020] Optionally, the first switch tube and the second switch tube are PMOS tubes; the third switch tube and the fourth switch tube are NMOS tubes.

[0021] Optionally, the driving module includes: a third optical coupler and a driving resistor;

[0022] The first end of the light-emitting side of the third optocoupler is connected to the control module, the second end of the light-emitting side of the third optocoupler is grounded, the first end of the light-receiving side of the third optocoupler is connected to the excitation module, the first end of the light-receiving side of the third optocoupler is also connected to the first end of the driving resistor, the second end of the driving resistor is connected to the negative pole of the battery pack, and the second end of the light-receiving side of the third optocoupler is connected to the positive pole of the battery pack.

[0023] Optionally, the excitation module includes: an excitation switch and an excitation resistor;

[0024] The control end of the excitation switch is connected to the driving module, the first end of the excitation switch is connected to the first end of the excitation resistor, the second end of the excitation resistor is connected to the positive electrode of the battery pack, the second end of the excitation switch is connected to the negative electrode of the battery pack, and the second end of the excitation switch is also connected to the control module.

[0025] Optionally, the control module includes: a control chip, a first capacitor, a second capacitor and a third capacitor;

[0026] The internal voltage end of the control chip is grounded through the first capacitor, the voltage monitoring end of the control chip is connected to the excitation module, the driving end of the control chip is connected to the driving module, the main detection end of the negative pole voltage of the battery cell of the control chip and the auxiliary detection end of the negative pole voltage of the battery cell of the control chip are connected to the negative pole of the battery cell through the switch unit, the main detection end of the negative pole voltage of the battery cell of the control chip, the auxiliary detection end of the negative pole voltage of the battery cell of the control chip, the reference ground end of the control chip, and the chip mode control end of the control chip are grounded, the battery cell response voltage end of the control chip is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the positive pole of the battery cell through the switch unit, the main detection end of the positive pole voltage of the battery cell of the control chip and the auxiliary detection end of the positive pole voltage of the battery cell of the control chip are connected to the second end of the second capacitor, the power supply end of the control chip is connected to the power supply voltage, and the power supply end of the control chip is also grounded through the third capacitor.

[0027] According to another aspect of the present invention, there is provided a method for controlling an electrochemical impedance spectroscopy measuring device, which is performed by the electrochemical impedance spectroscopy measuring device described in any of the above embodiments. The method for controlling an electrochemical impedance spectroscopy measuring device comprises:

[0028] Get the current status of each switch unit;

[0029] If all the switch units are turned off, a cell to be tested is selected from the cells and the switch unit corresponding to the cell to be tested is controlled to be turned on;

[0030] After the electrochemical impedance spectroscopy measurement of the measured cell is completed, controlling the switch unit corresponding to the measured cell to be turned off;

[0031] If at least one of the switch units is turned on, each of the switch units is controlled to be turned off, and the current state of each switch unit is re-acquired.

[0032] In an embodiment of the present invention, the switch units in the cell selection module select the cell to be tested. The control module controls the drive module to drive the excitation module to generate excitation currents of different frequencies. The control module calculates the impedance of the cell to be tested at different frequencies based on the voltage of the cell to be tested and the excitation current, thereby obtaining the electrochemical impedance spectrum of the cell. In an embodiment of the present invention, the switch units in the cell selection module select the cell to be measured by electrochemical impedance spectroscopy, thereby achieving multi-channel detection. This eliminates the need for a separate detection device for each cell, simplifies the architecture, and helps reduce the cost of measuring the electrochemical impedance spectrum of the cell.

[0033] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 Schematic diagram of an electrochemical impedance spectroscopy measuring device provided in an embodiment of the present invention;

[0036] Figure 2 is a schematic diagram of another electrochemical impedance spectroscopy measuring device provided by an embodiment of the present invention;

[0037] Figure 3 Schematic diagram of another electrochemical impedance spectroscopy measuring device provided by an embodiment of the present invention;

[0038] Figure 4 is a schematic diagram of a switch unit provided by an embodiment of the present invention.

[0039] Figure 5 Schematic diagram of another electrochemical impedance spectroscopy measuring device provided by an embodiment of the present invention;

[0040] Figure 6 Schematic diagram of another electrochemical impedance spectroscopy measuring device provided by an embodiment of the present invention;

[0041] Figure 7 This is a flow chart of a method for controlling an electrochemical impedance spectroscopy measurement device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] An embodiment of the present invention provides an electrochemical impedance spectroscopy (EIS) measuring device. This device is used to measure the EIS of a battery cell. This embodiment uses a switch unit in a cell selection module to select the battery cell for EIS measurement, enabling multi-channel detection. This eliminates the need for separate detection devices for each battery cell, resulting in a simple architecture and improved EIS measurement efficiency. Figure 1 Schematic diagram of an electrochemical impedance spectroscopy measuring device provided by an embodiment of the present invention. Figure 1 The electrochemical impedance spectroscopy measuring device includes: a cell selection module 110 , a control module 120 , a driving module 130 and an excitation module 140 .

[0045] The cell selection module 110 is connected to the battery pack, and the cell 10 in the battery pack is connected in series. The cell selection module 110 includes multiple switch units 111, and each switch unit 111 is connected to each cell 10 one by one. The positive pole of the cell 10 and the negative pole of the cell 10 are both connected to the control module 120 through the switch unit 111. The first end of the drive module 130 is connected to the control module 120, and the second end of the drive module 130 is grounded. The third and fourth ends of the drive module 130 are respectively connected to the positive pole and negative pole of the battery pack. The fifth end of the drive module 130 is connected to the excitation module 140, and the excitation module 140 is also respectively connected to the positive pole of the battery pack, the negative pole of the battery pack and the control module 120; the cell selection module 110 is used to select the cell to be tested; the drive module 130 is used to drive the excitation module 140; the excitation module 140 is used to generate an excitation current; and the control module 120 is used to calculate the electrochemical impedance spectrum of the cell to be tested based on the voltage and excitation current of the cell to be tested.

[0046] Specifically, each battery cell 10 in the battery pack has a corresponding switch unit 111. By controlling the on or off of the switch unit 111, the connection between the battery cell 10 connected to the switch unit 111 and the control module 120 can be controlled. It should be noted that only one switch unit 111 is turned on at a time, that is, only one battery cell 10 is connected to the control module 120 at a time. When a switch unit 111 in the chip selection module 110 is turned on, the battery cell 10 corresponding to the switch unit 111 is selected as the battery cell to be tested. At this time, the control module 120 can detect the voltage of the battery cell to be tested.

[0047] When the cell to be tested is selected and the switch unit 111 corresponding to the cell to be tested is turned on, the control module 120 enables the driving module 130 at a certain frequency, so that the driving module 130 continuously drives the excitation module 140 to be turned on and off at a certain frequency, thereby causing the branch where the excitation module 140 is located to generate an excitation current with a certain frequency. It should be noted that the frequency of the excitation current is related to the frequency at which the control module 120 enables the driving module 130, and the two are the same. Among them, the enabling of the driving module 130 by the control module 120 can be realized by a PWM (Pulse Width Modulation) signal at the same time. By changing the frequency of the PWM signal, the frequency of the excitation current generated by the excitation module 140 can be changed.

[0048] Based on the voltage and excitation current of the cell under test, the control module 120 calculates the impedance of the cell under test at the frequency corresponding to the excitation current. By enabling different frequencies of the drive module 130, the control module 120 causes the excitation module 140 to generate excitation currents of different frequencies, thereby obtaining the impedance of the cell under test at different frequencies and, in turn, the electrochemical impedance spectrum of the cell under test.

[0049] In the embodiment of the present invention, the switch units 111 in the cell selection module 110 select the cell to be tested. The control module 120 controls the drive module 130 to drive the excitation module 140 to generate excitation currents of different frequencies. The control module 120 calculates the impedance of the cell to be tested at different frequencies based on the voltage of the cell to be tested and the excitation current, thereby obtaining the electrochemical impedance spectrum of the cell. In the embodiment of the present invention, the switch units 111 in the cell selection module 110 select the cell to be measured by electrochemical impedance spectroscopy, thereby achieving multi-channel detection. This eliminates the need for a separate detection device for each cell 10, resulting in a simple architecture and reducing the cost of measuring the electrochemical impedance spectrum of the cell 10.

[0050] Figure 2 Schematic diagram of another electrochemical impedance spectroscopy measuring device provided by an embodiment of the present invention. Figure 2The switch unit 111 includes: a first switch 1111 and a second switch 1112 .

[0051] The first end of the first switch 1111 is connected to the positive electrode of the battery cell 10, the second end of the first switch 1111 is connected to the control module 120, the second end of the second switch 1112 is connected to the negative electrode of the battery cell 10, and the second end of the second switch 1112 is connected to the control module 120. The first switch 1111 and the second switch 1112 in the switch unit 111 are turned on or off at the same time. When the switch unit 111 is turned on, the positive electrode of the battery cell 10 connected to the switch unit 111 is connected to the control module 120 via the first switch 1111, and the negative electrode of the battery cell 10 connected to the switch unit 111 is connected to the control module 120 via the second switch 1112. For example, the first switch 1111 and the second switch 1112 can be mechanical switches, electronic switches, or relays, which are not limited in this embodiment.

[0052] Figure 3 This is a schematic diagram of another electrochemical impedance spectroscopy measuring device provided by an embodiment of the present invention. Figure 3 The battery cell selection module 110 also includes: a switch control unit 112.

[0053] Each switch unit 111 is connected to a switch control unit 112 ; the switch control unit 112 is used to control the on or off of each switch unit 111 .

[0054] Specifically, the on / off state of each switch unit 111 is controlled by a switch control unit 112. Each switch unit 111 has a corresponding switch control unit 112, and the number of switch units 111 is the same as the number of switch control units 112. In actual applications, each switch unit 111 may be connected to the same switch control unit 112, and the switch control unit 112 may independently control each switch unit 111 through different control port groups, i.e., each switch unit 111 is connected to a different port group of the same switch control unit 112.

[0055] Figure 4 is a schematic diagram of a switch unit provided by an embodiment of the present invention. Based on the above embodiments, optionally, Figure 3 and Figure 4 The switch unit 111 includes: a first switch component 1113 and a second switch component 1114.

[0056] A first end of the first switch component 1113 is connected to the positive end of the switch control unit 112, a second end of the first switch component 1113 is connected to the negative end of the switch control unit 112, a third end of the first switch component 1113 is connected to the negative electrode of the battery cell 10, a fourth end of the first switch component 1113 is connected to the positive electrode of the battery cell 10, a fifth end of the first switch component 1113 is connected to the control module 120, a first end of the second switch component 1114 is connected to the first end of the first switch component 1113, a second end of the second switch component 1114 is connected to the second end of the first switch component 1113, a third end of the second switch component 1114 is connected to the positive electrode of the battery cell 10, a fourth end of the second switch component 1114 is connected to the negative electrode of the battery cell 10, a fifth end of the second switch component 1114 is connected to the control module 120, the negative end of the switch control unit 112 is grounded, and the common end of the switch control unit 112 is connected to the negative end of the switch control unit 112.

[0057] Specifically, the first switch component 1113 and the second switch component 1114 are turned on or off simultaneously. When the switch units 111 correspond one-to-one with the switch control units 112, the first switch component 1113 and the second switch component 1114 are connected to the same switch control unit 112. Furthermore, in actual applications, each switch unit 111 can also be connected to the same switch control unit 112, and the switch control unit 112 can independently control each switch unit 111 through different control port groups. In this case, the first switch component 1113 and the second switch component 1114 are connected to the same port group. It should be noted that the port group of the switch control unit 112 includes a positive terminal, a negative terminal, and a common terminal.

[0058] On the basis of the above embodiments, optionally, continue to refer to Figure 4 The first switch component 1113 includes: a first optocoupler OC1, a first switch tube Q1, a second switch tube Q2 and a first switch resistor R2.

[0059] The first end of the light-emitting side of the first optocoupler OC1 is connected to the positive end of the switch control unit 112, the second end of the light-emitting side of the first optocoupler OC1 is connected to the negative end of the switch control unit 112, the first end of the light-receiving side of the first optocoupler OC1 is connected to the negative electrode of the battery cell 10, the second end of the light-receiving side of the first optocoupler OC1 is connected to the control end of the first switch tube Q1, the first end of the first switch tube Q1 is connected to the positive electrode of the battery cell 10, the second end of the first switch tube Q1 is connected to the first end of the second switch tube Q2, the second end of the second switch tube Q2 is connected to the control module 120, the control end of the second switch tube Q2 is connected to the control end of the first switch tube Q1, the first switch resistor R1 is connected between the control end and the second end of the first switch tube Q1, the negative end of the switch control unit 112 is grounded, and the common end of the switch control unit 112 is connected to the negative end of the switch control unit 112.

[0060] Continue to refer to Figure 4 The second switch component 1114 includes: a second optocoupler OC2, a third switch tube Q3, a fourth switch tube Q4 and a second switch resistor R2.

[0061] The first end of the light-emitting side of the second optocoupler OC2 is connected to the positive end of the switch control unit 112, the second end of the light-emitting side of the second optocoupler OC2 is connected to the negative end of the switch control unit 112, the first end of the light-receiving side of the second optocoupler OC2 is connected to the control end of the third switch tube Q3, the second end of the light-receiving side of the second optocoupler OC2 is connected to the positive electrode of the battery cell 10, the first end of the third switch tube Q3 is connected to the negative electrode of the battery cell 10, the second end of the third switch tube Q3 is connected to the first end of the fourth switch tube Q4, the second end of the fourth switch tube Q4 is connected to the control module 120, the control end of the fourth switch tube Q4 is connected to the control end of the third switch tube Q3, and the second switch resistor R2 is connected between the control end and the second end of the third switch tube Q3.

[0062] Specifically, the first switch Q1 and the second switch Q2 are turned on when the voltage is low. For example, the first switch Q1 and the second switch Q2 can be PMOS transistors. When the first optocoupler OC is turned on, the control terminals of the first switch Q1 and the second switch Q2 are both connected to the negative electrode of the battery cell 10. At this time, the first switch Q1 and the second switch Q2 are turned on.

[0063] Taking the first switch Q1 and the second switch Q2 as PMOS transistors as an example, when the first optocoupler OC1 is turned on under the control of the switch control unit 112, the control terminal of the first switch Q1 and the control terminal of the second switch Q2 are both connected to the negative electrode of the battery cell 10. At this time, the control terminal of the first switch Q1 is connected to the negative electrode of the battery cell 10, while the first terminal of the first switch Q1 is connected to the positive electrode of the battery cell 10. At this time, the voltage between the first terminal and the control terminal of the first switch Q1 meets the turn-on condition of the first switch Q1, and the first switch Q1 is turned on. When the first switch Q1 is turned on, the first terminal of the second switch Q2 is connected to the positive electrode of the battery cell 10. At this time, the voltage between the first terminal and the control terminal of the second switch Q2 meets the turn-on condition of the second switch Q2, and the second switch Q2 is turned on. The first switch resistor R1 stabilizes the potential of the control terminal of the first switch Q1 and the control terminal of the second switch Q2. In actual applications, a first switch capacitor C1 may also be provided at both ends of the first switch resistor R1.

[0064] The third switch Q3 and the fourth switch Q4 are turned on when the voltage is high. For example, the third switch Q3 and the fourth switch Q4 can be NMOS transistors. When the first optocoupler OC is turned on, the control terminals of the third switch Q3 and the fourth switch Q4 are both connected to the positive electrode of the battery cell 10. At this time, the third switch Q3 and the fourth switch Q4 are turned on.

[0065] Take the third switch tube Q3 and the fourth switch tube Q4 as NMOS tubes as an example. When the second optocoupler OC2 is turned on under the control of the switch control unit 112, the control end of the third switch tube Q3 and the control end of the fourth switch tube Q4 are both connected to the positive electrode of the battery cell 10. At this time, the control end of the third switch tube Q3 is connected to the positive electrode of the battery cell 10, and the first end of the third switch tube Q3 is connected to the negative electrode of the battery cell 10. At this time, the voltages of the first end and the control end of the third switch tube Q3 meet the turn-on condition of the third switch tube Q3, and the third switch tube Q3 is turned on. When the third switch tube Q3 is turned on, the first end of the fourth switch tube Q4 is connected to the negative electrode of the battery cell 10. At this time, the voltages of the first end and the control end of the fourth switch tube Q4 meet the turn-on condition of the fourth switch tube Q4, and the fourth switch tube Q4 is turned on. Among them, the second switch resistor R2 stabilizes the potential of the control end of the third switch tube Q3 and the control end of the fourth switch tube Q4.

[0066] In actual application, a first current limiting resistor R3 may be provided between the first optocoupler OC1 and the switch control unit 112, and a second current limiting resistor R4 may be provided between the second optocoupler OC2 and the switch control unit 112 to limit the current on the light-emitting side of the first optocoupler OC1 and the light-emitting side of the second optocoupler OC2.

[0067] Figure 5 This is a schematic diagram of another electrochemical impedance spectroscopy measuring device provided by an embodiment of the present invention. Figure 5 The excitation module 140 includes an excitation switch S1 and an excitation resistor R5.

[0068] The control end of the excitation switch S1 is connected to the driving module 130, the first end of the excitation switch S1 is connected to the first end of the excitation resistor R5, the second end of the excitation resistor R5 is connected to the positive electrode of the battery pack, the second end of the excitation switch S1 is connected to the negative electrode of the battery pack, and the second end of the excitation switch S1 is also connected to the control module 120.

[0069] Specifically, the excitation switch S1 is turned on by the driver module 130. When the driver module 130 continuously drives the excitation switch S1 on and off at a certain frequency, an excitation current with a certain frequency is generated in the branch containing the excitation switch S1 and the excitation resistor R5. The excitation resistor R5 limits the current in its branch to prevent a short circuit in the branch. Exemplarily, the excitation switch S1 can be a switching tube, a solid-state switch, or an electronic switch.

[0070] For example, the excitation current generated by the branch containing the excitation switch S1 and the excitation resistor R5 can be calculated by combining the total voltage of the battery pack and the resistance value of the excitation resistor R5. The total voltage of the battery pack can be obtained by adding the voltages of the individual battery cells 10. The control module 120 can detect the voltages of the individual battery cells 10 individually and sum them to obtain the total voltage of the battery pack. In actual applications, the resistance value of the excitation resistor R5 can be set according to actual needs, and this embodiment does not impose any restrictions on this.

[0071] Figure 6 This is a schematic diagram of another electrochemical impedance spectroscopy measuring device provided by an embodiment of the present invention. Figure 6 The driving module 130 includes: a third optical coupler OC3 and a driving resistor R6.

[0072] The first end of the light-emitting side of the third optocoupler OC3 is connected to the control module 120, the second end of the light-emitting side of the third optocoupler OC3 is grounded, the first end of the light-receiving side of the third optocoupler OC3 is connected to the excitation module 140, the first end of the light-receiving side of the third optocoupler OC3 is also connected to the first end of the driving resistor R6, the second end of the driving resistor R6 is connected to the negative pole of the battery pack, and the second end of the light-receiving side of the third optocoupler OC3 is connected to the positive pole of the battery pack.

[0073] The driving resistor R6 limits the current on the light-receiving side of the third optocoupler OC3. In practical applications, a third current-limiting resistor R7 can be further provided between the light-emitting side of the third optocoupler OC3 and ground to limit the current on the light-emitting side of the third optocoupler OC3.

[0074] Continue to refer to Figure 6 The control module 120 includes: a control chip U1, a first capacitor C2, a second capacitor C3 and a third capacitor C4.

[0075] The internal voltage VBAT_FIL of the control chip U1 is grounded through the first capacitor C2, the voltage monitoring terminal VDR of the control chip U1 is connected to the excitation module 140, the driving terminal VSW of the control chip U1 is connected to the driving module 130, the main negative electrode voltage detection terminal VCLg of the control chip U1 and the auxiliary negative electrode voltage detection terminal VCLm of the control chip U1 are connected to the negative electrode of the battery cell 10 through the switch unit 111, the main negative electrode voltage detection terminal VCLg of the control chip U1, the auxiliary negative electrode voltage detection terminal VCLm of the control chip U1, and the reference ground of the control chip U1 The terminal VSS and the chip mode control terminal SPI_EN of the control chip U1 are grounded, the battery cell response voltage terminal VHP of the control chip U1 is connected to the first end of the second capacitor C3, the second end of the second capacitor C3 is connected to the positive electrode of the battery cell 10 through the switch unit 111, the battery cell positive voltage main detection terminal VCHG of the control chip U1 and the battery cell positive voltage auxiliary detection terminal VCHM of the control chip U1 are connected to the second end of the second capacitor C3, the power supply terminal VBAT of the control chip U1 is connected to the power supply voltage VCC, and the power supply terminal VBAT of the control chip U1 is also grounded through the third capacitor C4.

[0076] Among them, the control chip U1 detects the conduction state of the excitation module 140 through its VDR terminal, and the control chip U1 controls the enablement of the driving module 130 based on the conduction state of the excitation module 140 at the VDR terminal. The VSW terminal of the control chip U1 controls the conduction of the light-emitting side of the third optocoupler OC3. For example, when the VSW terminal of the control chip U1 is at a low level, the light-emitting side of the third optocoupler OC3 is turned on; when the VSW terminal of the control chip U1 is at a high level, the light-emitting side of the third optocoupler OC3 is turned off. The VHP terminal of the control chip U1 detects the voltage of the battery cell under test. Among them, the second capacitor C3 filters the electric energy input to the VHP terminal of the control chip U1 to filter out the AC component in the electric energy.

[0077] In practical applications, the reference ground terminal VSS of the control chip U1 can be connected to the negative electrode of each battery cell 10 through each switch unit 111 to prevent the control chip U1 from being damaged due to measuring high voltage.

[0078] An embodiment of the present invention also provides a method for controlling an electrochemical impedance spectroscopy measuring device. Figure 7 This is a flow chart of a control method for an electrochemical impedance spectroscopy measuring device provided by an embodiment of the present invention. The control method for an electrochemical impedance spectroscopy measuring device is executed by the electrochemical impedance spectroscopy measuring device provided by any of the above embodiments. Figure 7 , the electrochemical impedance spectroscopy measuring device control method includes:

[0079] S110: Acquire the current status of each switch unit.

[0080] For example, the current state of each switch unit can be obtained by the enable state of the switch unit, wherein when the switch unit is enabled, the control state of the switch unit is a high level; when the switch unit is disabled, the control state of the switch unit is a low level.

[0081] S120 , determining whether all switch units are turned off; if so, executing S130 ; if not, executing S150 .

[0082] Specifically, when the control state of each switch unit is a low level, each switch unit is turned off; when the control state of at least one switch unit is a high level, it indicates that at least one switch unit is in an on state.

[0083] S130 , selecting a cell to be tested from the cells and controlling the switch unit corresponding to the cell to be tested to be turned on.

[0084] Specifically, in practical applications, the cell to be tested can be selected from the cells in the battery pack as needed. At any given moment, there is only one cell to be tested. When the cell to be tested is selected, the switch unit corresponding to the cell to be tested is turned on, and the electrochemical impedance spectrum of the cell to be tested is measured.

[0085] S140 , after the electrochemical impedance spectrum measurement of the measured cell is completed, controlling the switch unit corresponding to the measured cell to be turned off.

[0086] Illustratively, after the electrochemical impedance spectrum measurement of the measured cell is completed, enabling of the switch unit corresponding to the measured cell is stopped, so that the switch unit corresponding to the measured cell is turned off.

[0087] S150: Control each switch unit to turn off, and re-acquire the current state of each switch unit.

[0088] Exemplarily, each switch unit is stopped from being enabled, so that each switch unit is turned off. After each switch unit is stopped from being enabled, the current state of each switch unit is reacquired.

[0089] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0090] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. An electrochemical impedance spectroscopy measuring device, characterized in that: include: Battery cell selection module, control module, drive module and excitation module; The cell selection module is connected to the battery pack, and the cells in the battery pack are connected in series. The cell selection module includes a plurality of switch units, and each switch unit is connected to each cell in a one-to-one correspondence. The positive electrode of the cell and the negative electrode of the cell are both connected to the control module through the switch unit. The first end of the drive module is connected to the control module, and the second end of the drive module is grounded. The third and fourth ends of the drive module are respectively connected to the positive and negative electrodes of the battery pack. The fifth end of the drive module is connected to the excitation module. The excitation module is also respectively connected to the positive electrode of the battery pack, the negative electrode of the battery pack and the control module; The cell selection module is used to select the cell to be tested; the driving module is used to drive the excitation module; the excitation module is used to generate an excitation current; and the control module is used to calculate the electrochemical impedance spectrum of the cell to be tested based on the voltage of the cell to be tested and the excitation current.

2. The electrochemical impedance spectroscopy measuring device according to claim 1, characterized in that: The switch unit includes: a first switch and a second switch; The first end of the first switch is connected to the positive electrode of the battery cell, the second end of the first switch is connected to the control module, the second end of the second switch is connected to the negative electrode of the battery cell, and the second end of the second switch is connected to the control module.

3. The electrochemical impedance spectroscopy measuring device according to claim 1, characterized in that: The cell selection module also includes: a switch control unit; Each of the switch units is connected to the switch control unit; The switch control unit is used to control the on or off of each of the switch units.

4. The electrochemical impedance spectroscopy measuring device according to claim 3, characterized in that: The switch unit includes: a first switch component and a second switch component; The first end of the first switch assembly is connected to the positive end of the switch control unit, the second end of the first switch assembly is connected to the negative end of the switch control unit, the third end of the first switch assembly is connected to the negative electrode of the battery cell, the fourth end of the first switch assembly is connected to the positive electrode of the battery cell, the fifth end of the first switch assembly is connected to the control module, the first end of the second switch assembly is connected to the first end of the first switch assembly, the second end of the second switch assembly is connected to the second end of the first switch assembly, the third end of the second switch assembly is connected to the positive electrode of the battery cell, the fourth end of the second switch assembly is connected to the negative electrode of the battery cell, the fifth end of the second switch assembly is connected to the control module, the negative end of the switch control unit is grounded, and the common end of the switch control unit is connected to the negative end of the switch control unit.

5. The electrochemical impedance spectroscopy measuring device according to claim 4, characterized in that: The first switch component includes: a first optocoupler, a first switch tube, a second switch tube and a first switch resistor; The first end of the light-emitting side of the first optocoupler is connected to the positive end of the switch control unit, the second end of the light-emitting side of the first optocoupler is connected to the negative end of the switch control unit, the first end of the light-receiving side of the first optocoupler is connected to the negative electrode of the battery cell, the second end of the light-receiving side of the first optocoupler is connected to the control end of the first switching tube, the first end of the first switching tube is connected to the positive electrode of the battery cell, the second end of the first switching tube is connected to the first end of the second switching tube, the second end of the second switching tube is connected to the control module, the control end of the second switching tube is connected to the control end of the first switching tube, the first switch resistor is connected between the control end and the second end of the first switching tube, the negative end of the switch control unit is grounded, and the common end of the switch control unit is connected to the negative end of the switch control unit; The second switch component includes: a second optocoupler, a third switch tube, a fourth switch tube and a second switch resistor; The first end of the light-emitting side of the second optocoupler is connected to the positive end of the switch control unit, the second end of the light-emitting side of the second optocoupler is connected to the negative end of the switch control unit, the first end of the light-receiving side of the second optocoupler is connected to the control end of the third switch tube, the second end of the light-receiving side of the second optocoupler is connected to the positive electrode of the battery cell, the first end of the third switch tube is connected to the negative electrode of the battery cell, the second end of the third switch tube is connected to the first end of the fourth switch tube, the second end of the fourth switch tube is connected to the control module, the control end of the fourth switch tube is connected to the control end of the third switch tube, and the second switch resistor is connected between the control end and the second end of the third switch tube.

6. The electrochemical impedance spectroscopy measuring device according to claim 5, characterized in that: The first switch tube and the second switch tube are PMOS tubes; the third switch tube and the fourth switch tube are NMOS tubes.

7. The electrochemical impedance spectroscopy measuring device according to claim 1, characterized in that: The driving module includes: a third optical coupler and a driving resistor; The first end of the light-emitting side of the third optocoupler is connected to the control module, the second end of the light-emitting side of the third optocoupler is grounded, the first end of the light-receiving side of the third optocoupler is connected to the excitation module, the first end of the light-receiving side of the third optocoupler is also connected to the first end of the driving resistor, the second end of the driving resistor is connected to the negative pole of the battery pack, and the second end of the light-receiving side of the third optocoupler is connected to the positive pole of the battery pack.

8. The electrochemical impedance spectroscopy measuring device according to claim 1, characterized in that: The excitation module includes: an excitation switch and an excitation resistor; The control end of the excitation switch is connected to the driving module, the first end of the excitation switch is connected to the first end of the excitation resistor, the second end of the excitation resistor is connected to the positive electrode of the battery pack, the second end of the excitation switch is connected to the negative electrode of the battery pack, and the second end of the excitation switch is also connected to the control module.

9. The electrochemical impedance spectroscopy measuring device according to any one of claims 1 to 8, characterized in that: The control module includes: a control chip, a first capacitor, a second capacitor and a third capacitor; The internal voltage end of the control chip is grounded through the first capacitor, the voltage monitoring end of the control chip is connected to the excitation module, the driving end of the control chip is connected to the driving module, the main detection end of the negative pole voltage of the battery cell of the control chip and the auxiliary detection end of the negative pole voltage of the battery cell of the control chip are connected to the negative pole of the battery cell through the switch unit, the main detection end of the negative pole voltage of the battery cell of the control chip, the auxiliary detection end of the negative pole voltage of the battery cell of the control chip, the reference ground end of the control chip, and the chip mode control end of the control chip are grounded, the battery cell response voltage end of the control chip is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the positive pole of the battery cell through the switch unit, the main detection end of the positive pole voltage of the battery cell of the control chip and the auxiliary detection end of the positive pole voltage of the battery cell of the control chip are connected to the second end of the second capacitor, the power supply end of the control chip is connected to the power supply voltage, and the power supply end of the control chip is also grounded through the third capacitor.

10. A method for controlling an electrochemical impedance spectroscopy measuring device, characterized in that: The method is performed by the electrochemical impedance spectroscopy measuring device according to any one of claims 1 to 9, wherein the electrochemical impedance spectroscopy measuring device control method comprises: Get the current status of each switch unit; If all the switch units are turned off, a cell to be tested is selected from the cells and the switch unit corresponding to the cell to be tested is controlled to be turned on; After the electrochemical impedance spectroscopy measurement of the measured cell is completed, controlling the switch unit corresponding to the measured cell to be turned off; If at least one of the switch units is turned on, each of the switch units is controlled to be turned off, and the current state of each switch unit is re-acquired.

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