A sensing test chip and method for lithium ion batteries

Abstract

The application provides a lithium ion battery sensing test chip and method, which comprises an external interface module and an internal test module, the external interface module is used for connecting an external communication chip, a standard capacitor, a standard inductor and a lithium ion battery, the internal test module is connected with the external interface module, a control signal is input through the external communication chip, one of a parasitic inductance value and electrochemical impedance spectrum data of the lithium ion battery is measured according to the control signal, if the parasitic inductance value is measured, a known voltage parameter and a standard inductance value are collected and the parasitic inductance value is calculated, if the electrochemical impedance spectrum data is measured, a sine wave signal input by the external communication chip is converted, isolated and amplified to obtain the electrochemical impedance spectrum data. The application adds internal data of the lithium ion battery to a battery management system, makes data of the lithium ion battery diversified, and improves measurement data precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of integrated circuit design, and in particular to a lithium-ion battery sensing test chip and method. BACKGROUND

[0002] With the increasing application of lithium-ion batteries, the BMS (Battery Management System) as the link between the lithium-ion battery and the power system, the BMS (Battery Management System) monitors and manages the lithium-ion battery, which is crucial to the safety and reliability of the power system. Real-time perception of the safety state of the lithium-ion battery, especially accurate measurement of the internal temperature of the lithium-ion battery and precise identification of abnormal electrochemical behavior, can provide a basis for the decision-making of the BMS (Battery Management System). Although the performance of the BMS (Battery Management System) has improved a lot this year, the current way for the BMS (Battery Management System) to obtain the state of the lithium-ion battery is still based on the detection of simple physical quantities such as battery voltage, current and surface temperature, which cannot enable the BMS (Battery Management System) to accurately identify the complex electrochemical reaction process inside the lithium-ion battery from the root cause. When the BMS (Battery Management System) feeds back the state of the lithium-ion battery, the feedback data deviates from the actual situation of the internal reaction of the lithium-ion battery, resulting in a decrease in the safety of the lithium-ion power system.

[0003] The main technical problem to be solved at present is how to enable the BMS (Battery Management System) to obtain more lithium-ion battery data and make the monitoring of lithium-ion battery data more accurate. SUMMARY

[0004] In view of the above-mentioned shortcomings of the prior art, the present application provides a lithium-ion battery sensing test chip based on the measurement of electrochemical impedance spectroscopy data, which provides the BMS (Battery Management System) with electrochemical impedance spectroscopy data of the lithium-ion battery. The electrochemical impedance spectroscopy data reflects the electrochemical process inside the lithium-ion battery in real time, making the monitoring data more comprehensive.

[0005] To achieve the above object and other related objects, the technical scheme provided by the present application is as follows.

[0006] A sensor test chip of a lithium ion battery, comprising:

[0007] An external interface module for connecting an external communication chip, a standard capacitor, a standard inductor and a lithium ion battery; an internal test module connected with the external interface module for measuring a parasitic inductance value and electrochemical impedance spectrum data of the lithium ion battery; a control signal is input through the external communication chip, one of the parasitic inductance value and the electrochemical impedance spectrum data is measured according to the control signal, if the parasitic inductance value is measured, a known voltage parameter and a standard inductance value are collected, the parasitic inductance value is calculated according to the known voltage parameter and the standard inductance value, if the electrochemical impedance spectrum data is measured, a sine wave signal input by the external communication chip is converted, isolated and amplified to obtain the electrochemical impedance spectrum data.

[0008] Optionally, the external interface module comprises an external communication interface submodule, a capacitor interface submodule, an inductor interface submodule and a battery scanning interface submodule, the external communication interface submodule connects the internal test module with the external communication chip, the external communication chip is used for controlling the internal test module to measure the parasitic inductance value and the electrochemical impedance spectrum data, the external communication chip is also used for reading the measurement data of the internal test module, the capacitor interface submodule connects the internal test module with the standard capacitor, the standard capacitor is used for storing electric quantity and signal processing, the inductor interface submodule is used for connecting the internal test module with the standard inductor, the standard inductor provides a reference value for calculating the parasitic inductance value, and the battery scanning interface submodule connects the internal test module with a lithium ion battery group to be measured.

[0009] Optionally, the internal test module comprises a battery switching submodule, a switch submodule, a data processing submodule, a measurement electrochemical impedance spectrum data submodule and a direct current power supply submodule, the battery switching submodule connects the external communication interface submodule with the battery scanning interface submodule, the battery switching submodule is used for sequentially selecting and enabling the lithium ion battery and realizing scanning detection of the lithium ion battery group, the switch submodule connects the external communication interface submodule, the switch submodule is used for controlling the internal test module to measure the parasitic inductance value and the electrochemical impedance spectrum data, the data processing submodule is used for converting an electrical signal into a digital signal, the measurement electrochemical impedance spectrum data submodule is used for processing the sine wave signal and outputting electrochemical impedance spectrum data, and the direct current power supply submodule is used for charging the standard capacitor.

[0010] Optionally, the battery switching sub-module comprises a first data selector and a second data selector, the lithium ion battery pack comprises N lithium ion batteries, the battery scanning interface sub-module comprises N+1 ports, N inputs of the first data selector are connected to anodes of N lithium ion batteries through the 1st port to the Nth port of the battery scanning interface sub-module, N inputs of the second data selector are connected to cathodes of N lithium ion batteries through the 2nd port to the N+1th port of the battery scanning interface sub-module, wherein an output of the first data selector is a first output of the battery switching sub-module, and an output of the second data selector is a second output of the battery switching sub-module.

[0011] Optionally, the switch sub-module comprises a first NMOS tube, a second NMOS tube, a third NMOS tube, a fourth NMOS tube and a fifth NMOS tube, a source of the first NMOS is connected to a positive electrode of a direct current power supply, a drain of the first NMOS is connected to one end of a standard inductor through the inductor interface sub-module, the drain of the first NMOS is also connected to a drain of the second NMOS, the drain of the second NMOS is connected to a negative input end of a first analog-to-digital converter, a source of the second NMOS is connected to a common terminal of the direct current power supply, a second analog-to-digital converter, a first digital-to-analog converter and the second data selector, a source of the third NMOS is connected to a common terminal of the first amplifier and the first converter, a drain of the third NMOS is connected to a source of the fourth NMOS, the drain of the third NMOS is also connected to a drain of the fifth NMOS, a drain of the fourth NMOS is connected to an output of the first data selector, the drain of the fourth NMOS is connected to the other end of a standard capacitor through the capacitor interface sub-module, a drain of the fifth NMOS is connected to a positive input end of the first analog-to-digital converter, the drain of the fifth NMOS is also connected to one end of the standard capacitor through the capacitor interface sub-module, the drain of the fifth NMOS is also connected to the other end of the standard inductor through the inductor interface sub-module, a source of the fifth NMOS is connected to a positive input end of the second analog-to-digital converter, and the source of the fifth NMOS is also connected to an output of a first filter, wherein a base of the first NMOS, a base of the second NMOS, a base of the third NMOS, a base of the fourth NMOS and a base of the fifth NMOS are input terminals of the switch sub-module.

[0012] Optionally, the data processing sub-module comprises the first analog-to-digital converter and the second analog-to-digital converter, the negative input terminal of the first analog-to-digital converter is connected to one end of the standard inductor through the inductor interface sub-module, the negative input terminal of the first analog-to-digital converter is also connected to the drain of the first NMOS transistor and the drain of the second NMOS transistor, the positive input terminal of the first analog-to-digital converter is connected to the other end of the standard inductor through the inductor interface sub-module, the positive input terminal of the first analog-to-digital converter is connected to one end of the standard capacitor through the capacitor interface sub-module, the positive input terminal of the first analog-to-digital converter is also connected to the drain of the fifth NMOS transistor, the negative input terminal of the second analog-to-digital converter is connected to the common terminal of the second NMOS transistor, the second data selector, the direct current power supply and the first digital-to-analog converter, the positive input terminal of the second analog-to-digital converter is connected to the source of the fifth NMOS transistor, and the positive input terminal of the second analog-to-digital converter is also connected to the output terminal of the first filter.

[0013] Optionally, the measurement electrochemical impedance spectrum data sub-module comprises the first digital-to-analog converter, the first amplifier, the first filter and the first converter, the input terminal of the first digital-to-analog converter is connected to the common terminal of the second NMOS transistor, the second data selector, the second analog-to-digital converter and the direct current power supply, the output terminal of the first digital-to-analog converter is also connected to the input terminal of the first converter, the output terminal of the first converter is connected to the source of the third NMOS transistor, the output terminal of the first converter is also connected to the input terminal of the first amplifier, the output terminal of the first amplifier is connected to the input terminal of the first filter, the output terminal of the first filter is connected to the source of the fifth NMOS transistor, and the output terminal of the first filter is also connected to the positive input terminal of the second analog-to-digital converter.

[0014] A sensing test method of a lithium ion battery, comprising:

[0015] One of the parasitic inductance value and the electrochemical impedance spectrum data is measured through the control signal;

[0016] When the parasitic inductance value is measured, the switching control sub-module is controlled by converting the control signal, the known voltage parameter is collected, and the parasitic inductance value is calculated according to the known voltage parameter and the standard inductance value;

[0017] When the electrochemical impedance spectrum data is measured, the input sine wave signal is converted into an excitation current, the voltage signal is obtained after the excitation current flows through the lithium ion battery, the voltage signal is isolated, amplified and converted to obtain the electrochemical impedance spectrum data.

[0018] Optionally, when measuring the parasitic inductance value, the step of acquiring the known voltage parameter by converting the control signal to control the switch control sub-module, comprising: if the first NMOS tube, the second NMOS tube and the third NMOS tube are off and the fourth NMOS tube and the fifth NMOS tube are on, a first voltage value is acquired, the first voltage value is an open circuit voltage value of the lithium ion battery; if the second NMOS tube, the third NMOS tube and the fourth NMOS tube are off and the first NMOS tube and the fifth NMOS tube are on, the standard capacitor is in a charging state, a second voltage value is acquired, the second voltage value includes the first voltage value and a standard capacitor preset voltage threshold, the standard capacitor preset voltage threshold is obtained by subtracting the first voltage value from the second voltage value; if the first NMOS tube, the third NMOS tube and the fourth NMOS tube are off and the second NMOS tube and the fifth NMOS tube are on, the standard capacitor is in a discharging state, a third voltage value and a fourth voltage value are acquired, wherein the third voltage value is a voltage value of the standard inductance, and the fourth voltage value is a sum of the first voltage value, the standard capacitor preset voltage threshold and the parasitic inductance voltage.

[0019] Optionally, the step of obtaining electrochemical impedance spectrum data, comprising: when the first NMOS tube, the second NMOS tube, the fourth NMOS tube and the fifth NMOS tube are off and the third NMOS tube is on, measuring electrochemical impedance spectrum data; converting the input sine wave signal into the excitation current by the first converter, the lithium ion battery triggers the excitation current to obtain the voltage signal, isolating, amplifying and converting the voltage signal to obtain the electrochemical impedance spectrum data signal.

[0020] The application provides a technical scheme of a sensing test chip of a lithium ion battery, an external interface module of the scheme is connected with an external communication chip, a standard capacitor, a standard inductor and the lithium ion battery, an internal interface module is connected with the external interface module, a control signal is input through the external communication chip, one of a parasitic inductance value and electrochemical impedance spectrum data of the lithium ion battery is measured according to the control signal, when the parasitic inductance value is measured, the voltage parameter and the standard inductance value are collected and the parasitic inductance value is calculated, when the electrochemical impedance spectrum data is measured, a sine wave signal input to the external communication chip is converted, isolated and amplified to obtain the electrochemical impedance spectrum data. The application designs a technical scheme of a sensing test chip of a lithium ion battery, the technical scheme can measure the parasitic inductance value and the electrochemical impedance spectrum data of the lithium ion battery, the technical scheme can be compatible with a traditional BMS (Battery Management System, battery management system), the parasitic inductance data and the electrochemical impedance spectrum data of the lithium ion battery are provided for the BMS (Battery Management System, battery management system), the monitoring data is diversified, and the accuracy of the monitoring data is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a principle diagram of a chip architecture in the embodiment of the application;

[0022] Figure 2 It is a principle diagram of a chip for sensing and testing a lithium ion battery in the embodiment of the application;

[0023] Figure 3 It is a principle diagram for measuring an open circuit voltage of a lithium ion battery in the embodiment of the application;

[0024] Figure 4 It is a principle diagram for charging a standard capacitor in the embodiment of the application;

[0025] Figure 5 It is a principle diagram for discharging a standard capacitor in the embodiment of the application;

[0026] Figure 6 It is a principle diagram for measuring electrochemical impedance spectrum data in the embodiment of the application. DETAILED DESCRIPTION

[0027] The embodiments of the application are described below through specific concrete examples, and other advantages and effects of the application can be easily understood by those skilled in the art from the disclosure. The application can also be implemented or applied through other different specific embodiments, and each detail in the specification can be modified or changed based on different views and applications without departing from the spirit of the application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0028] Need to explain, the following examples provided in the illustration only to illustrate the basic idea of the present invention, the drawing shows only the components related to the invention in the actual implementation, not the number of components, shape and size of the drawing, the actual implementation of each component type, quantity and proportion can be a voluntary change, and its component layout type can be more complex.

[0029] The role of BMS (Battery Management System, battery management system) in monitoring and managing lithium ion batteries mainly has the following three aspects: one is to accurately estimate the remaining capacity of the battery pack, to ensure that it is maintained within a reasonable range, to prevent excessive charging and discharging from damaging the battery; second, dynamically monitor the working state of the battery pack, real-time collection of battery pack and cell voltage, current and temperature; three, protect the battery, avoid the battery working in extreme conditions to shorten the battery life, damage, and even cause explosion, fire and other hazards to personal safety accidents.

[0030] The inventor found that the current BMS (Battery Management System, battery management system) is mainly the measurement of the physical quantity of lithium ion batteries, and does not monitor the complex electrochemical reaction process inside the lithium ion battery. When monitoring the lithium ion battery, when the internal electrochemical reaction is abnormal, it cannot be effectively monitored, which will reduce the safety of the power system and increase the risk of using lithium ion batteries.

[0031] In view of the above situation, the present application provides a kind of compatible BMS (Battery Management System, battery management system) lithium ion battery sensing test chip related technical solutions, the sensing test chip designed by external interface module and internal test module, one of the parasitic inductance value and electrochemical impedance spectrum data of lithium ion battery can be measured by the control signal input by external communication chip, lithium ion battery internal electrochemical reaction can be real-time feedback, provide more accurate lithium ion battery internal state information for BMS (Battery Management System, battery management system), more comprehensive for the monitoring of lithium ion battery, thereby guaranteeing the safety of power.

[0032] As shown in Figure 1 The present application provides a kind of sensing test chip of lithium ion battery, which comprises:

[0033] The external interface module is connected with the external communication chip, the standard capacitor, the standard inductor and the lithium ion battery; the internal test module is connected with the external interface module and is used for measuring the parasitic inductance value and the electrochemical impedance spectrum data of the lithium ion battery; the control signal is input through the external communication chip, one of the parasitic inductance value and the electrochemical impedance spectrum data is measured according to the control signal, if the parasitic inductance value is measured, the known voltage parameter and the standard inductance value are collected, the parasitic inductance value is calculated according to the known voltage parameter and the standard inductance value, and if the electrochemical impedance spectrum data is measured, the sine wave signal input by the external communication chip is converted, isolated and amplified to obtain the electrochemical impedance spectrum data.

[0034] In detail, as shown in Figure 2 The external interface module includes an external communication interface submodule, a capacitor interface submodule, an inductor interface submodule and a battery scanning interface submodule, the external communication interface submodule is connected with the internal test module and the external communication chip, the external communication chip is used for controlling the internal test module to measure the parasitic inductance value and the electrochemical impedance spectrum data, the external communication chip is also used for reading the measurement data of the internal test module, the capacitor interface submodule is connected with the internal test module and the standard capacitor, the standard capacitor is used for storing the electric quantity and signal processing, the inductor interface submodule is used for connecting the internal test module and the standard inductor, the standard inductor provides a reference value for calculating the parasitic inductance value, and the battery scanning interface submodule is connected with the internal test module and the lithium ion battery group to be measured.

[0035] In detail, as shown in Figure 2 The internal test module includes a battery switching submodule, a switch submodule, a data processing submodule, an electrochemical impedance spectrum data measuring submodule and a direct current power supply submodule, the battery switching submodule is connected with the external communication interface submodule and the battery scanning interface submodule, the battery switching submodule is used for sequentially selecting and scanning detecting the lithium ion battery group, the switch submodule is connected with the external communication interface submodule, the switch submodule is used for controlling the internal test module to measure the parasitic inductance value and the electrochemical impedance spectrum data, the data processing submodule is used for converting the electric signal into a digital signal, the electrochemical impedance spectrum data measuring submodule is used for processing the sine wave signal and outputting the electrochemical impedance spectrum data, and the direct current power supply submodule is used for charging the standard capacitor.

[0036] In detail, the external communication chip controls the selection of the lithium ion battery by the battery switching submodule; the external communication chip inputs the control signal to control five NMOS tubes in the switch submodule, and one of the parasitic inductance value and the electrochemical impedance spectrum data is measured; the external communication chip reads the data of the data processing submodule.

[0037] More specifically, as shown in Figure 2As shown, the battery switching sub-module includes a first data selector MUX1 and a second data selector MUX2, the lithium ion battery pack includes 16 lithium ion batteries, the battery scan interface sub-module includes 17 ports, 16 input terminals of the first data selector are connected to the positive poles of the 16 lithium ion batteries through the 1st port to the 16th port of the battery scan interface sub-module, 16 input terminals of the second data selector are connected to the negative poles of the 16 lithium ion batteries through the 2nd port to the 17th port of the battery scan interface sub-module, wherein the output terminal of the first data selector MUX1 is the first output terminal of the battery switching sub-module, and the output terminal of the second data selector MUX2 is the second output terminal of the battery switching sub-module.

[0038] In more detail, as shown in the figure, Figure 2 As shown, the switch sub-module includes a first NMOS tube Q1, a second NMOS tube Q2, a third NMOS tube Q3, a fourth NMOS tube Q4, and a fifth NMOS tube Q5, the source electrode of the first NMOS tube Q1 is connected to the positive pole of the direct current power supply, the drain electrode of the first NMOS tube Q1 is connected to one end of the standard inductor through the inductor interface sub-module, the drain electrode of the first NMOS tube Q1 is also connected to the drain electrode of the second NMOS tube Q2, the drain electrode of the second NMOS tube Q2 is connected to the input negative pole of the first analog-to-digital converter A / D1, the source electrode of the second NMOS tube Q2 is connected to the common terminal of the direct current power supply LD0, the second analog-to-digital converter A / D2, the first digital-to-analog converter D / A, and the second data selector MUX2, the source electrode of the third NMOS tube Q3 is connected to the common terminal of the first amplifier INA and the first converter V / I, the drain electrode of the third NMOS tube Q3 is connected to the source electrode of the fourth NMOS tube Q4, the drain electrode of the third NMOS tube Q3 is also connected to the drain electrode of the fifth NMOS tube Q5, the drain electrode of the fourth NMOS tube Q4 is connected to the output terminal of the first data selector MUX1, the drain electrode of the fourth NMOS tube Q4 is connected to the other end of the standard capacitor C1 through the capacitor interface sub-module, the drain electrode of the fifth NMOS tube Q5 is connected to the input positive pole of the first analog-to-digital converter A / D1, the drain electrode of the fifth NMOS tube Q5 is also connected to one end of the standard capacitor C1 through the capacitor interface sub-module, the drain electrode of the fifth NMOS tube Q5 is also connected to the other end of the standard inductor L1 through the inductor interface sub-module, the source electrode of the fifth NMOS tube Q5 is connected to the input positive pole of the second analog-to-digital converter A / D2, and the source electrode of the fifth NMOS tube Q5 is also connected to the output terminal of the first filter BPF, wherein the base electrode of the first NMOS tube Q1, the base electrode of the second NMOS tube Q2, the base electrode of the third NMOS tube Q3, the base electrode of the fourth NMOS tube Q4, and the base electrode of the fifth NMOS tube Q5 are the input terminals of the switch sub-module.

[0039] In more detail, as shown in the figure, Figure 2As shown, the data processing sub-module includes a first analog-to-digital converter A / D1 and a second analog-to-digital converter A / D2, the negative input terminal of the first analog-to-digital converter A / D1 is connected to one end of a standard inductor L1 through the inductor interface sub-module, the negative input terminal of the first analog-to-digital converter A / D1 is also connected to the drain of a first NMOS tube Q1 and the drain of a second NMOS tube Q2, the positive input terminal of the first analog-to-digital converter A / D1 is connected to the other end of the standard inductor L1 through the inductor interface sub-module, the positive input terminal of the first analog-to-digital converter A / D1 is connected to one end of a standard capacitor C1 through the capacitor interface sub-module, and the positive input terminal of the first analog-to-digital converter A / D1 is also connected to the drain of a fifth NMOS tube Q5, the negative input terminal of the second analog-to-digital converter A / D2 is connected to the common terminal of the second NMOS tube Q2, a second data selector MUX2, a direct current power supply LD0 and a first digital-to-analog converter D / A, the positive input terminal of the second analog-to-digital converter A / D2 is connected to the source of the fifth NMOS tube Q5, and the positive input terminal of the second analog-to-digital converter A / D2 is also connected to the output terminal of a first filter BPF.

[0040] In more detail, as shown in Figure 2 The measurement electrochemical impedance spectroscopy data sub-module includes a first digital-to-analog converter D / A, a first amplifier INA, a first filter BFP and a first converter V / I, the input terminal of the first digital-to-analog converter D / A is connected to the common terminal of the second NMOS tube Q2, a second data selector MUX2, a second analog-to-digital converter A / D2 and a direct current power supply LD0, the output terminal of the first digital-to-analog converter D / A is also connected to the input terminal of the first converter V / I, the output terminal of the first converter V / I is connected to the source of a third NMOS tube Q3, the output terminal of the first converter V / I is also connected to the input terminal of the first amplifier INA, the output terminal of the first amplifier INA is connected to the input terminal of the first filter BFP, the output terminal of the first filter BFP is connected to the source of the fifth NMOS tube Q5, and the output terminal of the first filter BFP is also connected to the positive input terminal of the second analog-to-digital converter MUX2.

[0041] In more detail, as shown in Figure 3 Figure 6 The specific working principle of the lithium ion battery sensing test chip is as follows:

[0042] The external communication chip selects a lithium ion battery to be measured in the lithium ion battery pack through the battery switching sub-module of the external interface module, inputs a control signal through the external communication interface sub-module, and the internal measurement module measures one of the parasitic inductance value and the electrochemical impedance spectroscopy data according to the control signal.

[0043] 1) When measuring the parasitic inductance value, the working principle is divided into the following three steps:

[0044] First, as shown in Figure 3 ​As shown, when the first NMOS transistor Q1, the second NMOS transistor Q2 and the third NMOS transistor Q3 are turned off and the fourth NMOS transistor Q4 and the fifth NMOS transistor Q5 are turned on, the second analog-to-digital converter measures the open circuit voltage U across the lithium-ion battery to be tested. VS ;

[0045] Secondly, if Figure 4 As shown, when the second NMOS transistor Q2, the third NMOS transistor Q3 and the fourth NMOS transistor Q4 are turned off and the first NMOS transistor Q1 and the fifth NMOS transistor Q5 are turned on, after a few seconds, the DC power supply LD0 charges the voltage across the standard capacitor C1 to the preset voltage threshold U0, and the second analog-to-digital converter A / D2 displays the voltage value U BC is the open circuit voltage U between the standard capacitor C1 and the lithium-ion battery to be tested VS The preset voltage threshold U0 of the standard capacitor C1 is U BC -U VS ;

[0046] Finally, if Figure 5 As shown, when the first NMOS transistor Q1, the third NMOS transistor Q3, and the fourth NMOS transistor Q4 are turned off and the second NMOS transistor Q2 and the fifth NMOS transistor Q5 are turned on, the standard capacitor C1 begins to discharge, and an induced electromotive force is generated across the standard inductor L1 and the lithium-ion battery parasitic inductance Lx. Due to the equal current characteristic in the series circuit, the instantaneous discharge current remains zero. The first analog-to-digital converter A / D1 displays the voltage value U L1 is the voltage across the standard inductor L1, and the second analog-to-digital converter A / D2 displays the voltage value U BCL is the open circuit voltage U of the lithium-ion battery VS +Standard capacitor C1 voltage U0+Lithium-ion battery parasitic inductance voltage U x , get the parasitic inductance voltage U of the lithium-ion battery x＝ U BCL -U VS -U0; According to the preset voltage threshold U0=U of the standard capacitor C1 BC -U VS , calculate the parasitic inductance voltage U x＝ U BCL -2U VS -U BC .

[0047] Based on the characteristic that the current i in the series circuit is equal, the expression (1) is obtained to calculate the parasitic inductance value of the lithium-ion battery;

[0048]

[0049] Among them, U x Represents the voltage across the parasitic inductance, Lx represents a parasitic inductance value, U L1 voltage across, L1 is a standard inductance value;

[0050] According to expression (1), the parasitic inductance value is calculated, as shown in expression (2):

[0051]

[0052] 2) When measuring the electrochemical impedance spectrum data of the lithium ion battery, the specific working principle is as follows:

[0053] When the first NMOS tube Q1, the second NMOS tube Q2, the fourth NMOS tube Q4 and the fifth NMOS tube Q5 are cut off and the third NMOS tube Q3 is turned on, the external communication chip inputs a sinusoidal signal to the first digital-to-analog converter D / A1 in the measurement electrochemical impedance spectrum data submodule through the external communication interface submodule, the first digital-to-analog converter D / A1 outputs a fixed frequency or full frequency analog sinusoidal wave, and the first converter V / I is a sinusoidal wave AC constant current source, which provides an excitation current source for the lithium ion battery, and the current regulation range is 50-100mA; After the sinusoidal wave AC constant current source passes through the lithium ion battery, a voltage signal is generated across the lithium ion battery, and the voltage signal generated by the small internal resistance of the lithium ion battery is μV level, after passing through the standard capacitor, the AC part is reserved, and the first amplifier INA is used to amplify the AC sinusoidal wave voltage signal to an mV level voltage signal, and the amplified voltage signal is input to the second analog-to-digital converter A / D2 after passing through the first filter BPF, the second analog-to-digital converter A / D2 converts the filtered voltage signal into a digital signal, and the external communication chip reads the electrochemical impedance spectrum data converted by the second analog-to-digital converter.

[0054] The application also provides a sensing test method for a lithium ion battery, comprising:

[0055] S1, providing the sensing test chip for the lithium ion battery;

[0056] S2, measuring one of the parasitic inductance value and the electrochemical impedance spectrum data through a control signal;

[0057] S3, when measuring the parasitic inductance value, the switch control submodule is controlled through a conversion control signal, the known voltage parameter is collected, and the parasitic inductance value is calculated according to the voltage parameter and the standard inductance value;

[0058] In detail, when measuring the parasitic inductance value, the step of collecting the known voltage parameter by controlling the switch control sub-module through the conversion control signal includes: collecting the first voltage value if the first NMOS tube Q1, the second NMOS tube Q2 and the third NMOS tube Q3 are off and the fourth NMOS tube Q4 and the fifth NMOS tube Q5 are on, the first voltage value being the open circuit voltage value of the lithium ion battery; collecting the second voltage value if the second NMOS tube Q2, the third NMOS tube Q3 and the fourth NMOS tube Q4 are off and the first NMOS tube Q1 and the fifth NMOS tube Q5 are on, the standard capacitor being in a charging state, the second voltage value including the first voltage value and a standard capacitor preset voltage threshold, and the standard capacitor preset voltage threshold being obtained by subtracting the first voltage value from the second voltage value; collecting the third voltage value and the fourth voltage value if the first NMOS tube Q1, the third NMOS tube Q3 and the fourth NMOS tube Q4 are off and the second NMOS tube Q2 and the fifth NMOS tube Q5 are on, the standard capacitor being in a discharging state, the third voltage value being the voltage value of the standard inductance, and the fourth voltage value being the sum of the first voltage value, the standard capacitor preset voltage threshold and the parasitic inductance voltage.

[0059] S4, when measuring the electrochemical impedance spectrum data, converting the input sine wave signal into an excitation current, obtaining a voltage signal after the excitation current flows through the lithium ion battery, isolating, amplifying and converting the voltage signal to obtain the electrochemical impedance spectrum data.

[0060] In detail, the step of obtaining the electrochemical impedance spectrum data includes: measuring the electrochemical impedance spectrum data when the first NMOS tube Q1, the second NMOS tube Q2, the fourth NMOS tube Q4 and the fifth NMOS tube Q5 are off and the third NMOS tube Q3 is on; converting the input sine wave signal into an excitation current through the first converter, detecting a voltage signal at both ends of the lithium ion battery after the lithium ion battery triggers the excitation current, outputting the voltage signal after the excitation current passes through the lithium ion battery, isolating, amplifying and converting the voltage signal to obtain the electrochemical impedance spectrum data signal.

[0061] The sensor test technical scheme of the lithium ion battery is specifically described in the embodiment of the application, and the scheme designs a chip architecture for measuring the parasitic inductance value and electrochemical impedance spectrum data of the lithium ion battery. An external chip input control signal is used to measure one of the parasitic inductance value and the electrochemical impedance spectrum data of the lithium ion battery according to the control signal. When the parasitic inductance value is measured, a known voltage parameter and a standard inductance value are collected through the control signal, and the parasitic inductance value is calculated according to the known voltage parameter and the standard inductance value. When the electrochemical impedance spectrum data is measured, the input sinusoidal signal is converted, isolated and amplified to obtain the electrochemical impedance spectrum data. The sensor test technical scheme of the lithium ion battery designed in the application measures the parasitic inductance value and the electrochemical impedance spectrum data of the lithium ion battery, is compatible with the existing BMS (Battery Management System, battery management system), provides more lithium ion battery data for the BMS (Battery Management System, battery management system), can more intuitively feedback the internal chemical reaction of the lithium ion battery, and reduces the risk of using the lithium ion battery.

[0062] The above embodiments only exemplarily illustrate the principles and effects of the application, and are not used to limit the application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the application should be covered by the claims of the application.

Claims

1. A sensor test chip for lithium-ion batteries, characterized in that: include: External interface module, used to connect external communication chips, standard capacitors, standard inductors and lithium-ion batteries; The internal test module is connected to the external interface module and is used to measure the parasitic inductance value and electrochemical impedance spectroscopy data of the lithium-ion battery; A control signal is input through the external communication chip, and one of the parasitic inductance value and the electrochemical impedance spectroscopy data is measured according to the control signal. If the parasitic inductance value is measured, known voltage parameters and standard inductance values ​​are collected, and the parasitic inductance value is calculated based on the known voltage parameters and standard inductance values. If the electrochemical impedance spectroscopy data is measured, the sinusoidal wave signal input by the external communication chip is converted, isolated, and amplified to obtain the electrochemical impedance spectroscopy data.

2. The sensor test chip for lithium-ion batteries according to claim 1, characterized in that: The external interface module includes an external communication interface submodule, a capacitance interface submodule, an inductance interface submodule and a battery scanning interface submodule. The external communication interface submodule connects the internal test module and the external communication chip. The external communication chip is used to control the internal test module to measure the parasitic inductance value and the electrochemical impedance spectrum data. The external communication chip is also used to read the measurement data of the internal test module. The capacitance interface submodule connects the internal test module and the standard capacitor. The standard capacitor is used for storing electricity and signal processing. The inductance interface submodule is used to connect the internal test module and the standard inductor. The standard inductor provides a reference value for calculating the parasitic inductance value. The battery scanning interface submodule connects the internal test module and the lithium-ion battery pack to be tested.

3. The sensor test chip for lithium-ion batteries according to claim 2, characterized in that: The internal test module includes a battery switching submodule, a switch submodule, a data processing submodule, an electrochemical impedance spectrum data measurement submodule, and a DC power supply submodule. The battery switching submodule is connected to the external communication interface submodule and the battery scanning interface submodule. The battery switching submodule is used to sequentially select the lithium-ion batteries and perform scanning detection of the lithium-ion battery pack. The switch submodule is connected to the external communication interface submodule. The switch submodule is used to control the internal test module to measure the parasitic inductance value and the electrochemical impedance spectrum data. The data processing submodule is used to convert electrical signals into digital signals. The electrochemical impedance spectrum data measurement submodule is used to process the sinusoidal wave signal and output the electrochemical impedance spectrum data. The DC power supply submodule is used to charge the standard capacitor.

4. The sensor test chip for lithium-ion batteries according to claim 3, characterized in that: The battery switching submodule includes a first data selector and a second data selector. The lithium-ion battery pack includes N lithium-ion batteries. The battery scanning interface submodule includes an N+1 port. The N input ends of the first data selector are connected to the positive electrodes of the N lithium-ion batteries through the first port to the Nth port of the battery scanning interface submodule. The N input ends of the second data selector are connected to the negative electrodes of the N lithium-ion batteries through the second port to the N+1th port of the battery scanning interface submodule. The output end of the first data selector is the first output end of the battery switching submodule, and the output end of the second data selector is the second output end of the battery switching submodule.

5. The sensor test chip for lithium-ion batteries according to claim 4, characterized in that: The switch submodule includes a first NMOS transistor, a second NMOS transistor, a third NMOS transistor, a fourth NMOS transistor and a fifth NMOS transistor. The source of the first NMOS transistor is connected to the positive electrode of the DC power supply, the drain of the first NMOS transistor is connected to one end of the standard inductor through the inductor interface submodule, the drain of the first NMOS transistor is also connected to the drain of the second NMOS transistor, the drain of the second NMOS transistor is connected to the negative input terminal of the first analog-to-digital converter, the source of the second NMOS transistor is connected to the common terminal of the DC power supply, the second analog-to-digital converter, the first digital-to-analog converter and the second data selector, the source of the third NMOS transistor is connected to the common terminal of the first amplifier and the first converter, the drain of the third NMOS transistor is connected to the source of the fourth NMOS transistor, the drain of the third NMOS transistor is also connected to the drain of the fifth NMOS transistor, and the The drains of the four NMOS transistors are connected to the output end of the first data selector, the drain of the fourth NMOS transistor is connected to the other end of the standard capacitor through the capacitor interface submodule, the drain of the fifth NMOS transistor is connected to the positive input end of the first analog-to-digital converter, the drain of the fifth NMOS transistor is also connected to one end of the standard capacitor through the capacitor interface submodule, the drain of the fifth NMOS transistor is also connected to the other end of the standard inductor through the inductor interface submodule, the source of the fifth NMOS transistor is connected to the positive input end of the second analog-to-digital converter, and the source of the fifth NMOS transistor is also connected to the output end of the first filter, wherein the bases of the first NMOS transistor, the second NMOS transistor, the third NMOS transistor, the fourth NMOS transistor, and the fifth NMOS transistor are the input ends of the switch submodule.

6. The sensor test chip for lithium-ion batteries according to claim 5, characterized in that: The data processing submodule includes the first analog-to-digital converter and the second analog-to-digital converter. The negative input terminal of the first analog-to-digital converter is connected to one end of the standard inductor through the inductor interface submodule. The negative input terminal of the first analog-to-digital converter is also connected to the drain of the first NMOS transistor and the drain of the second NMOS transistor. The positive input terminal of the first analog-to-digital converter is connected to the other end of the standard inductor through the inductor interface submodule. The positive input terminal of the first analog-to-digital converter is connected to one end of the standard capacitor through the capacitor interface submodule. The positive input terminal of the first analog-to-digital converter is also connected to the drain of the fifth NMOS transistor. The negative input terminal of the second analog-to-digital converter is connected to the common terminal of the second NMOS transistor, the second data selector, the DC power supply, and the first digital-to-analog converter. The positive input terminal of the second analog-to-digital converter is connected to the source of the fifth NMOS transistor. The positive input terminal of the second analog-to-digital converter is also connected to the output terminal of the first filter.

7. The sensor test chip for lithium-ion batteries according to claim 5, characterized in that: The electrochemical impedance spectroscopy data measuring submodule includes the first digital-to-analog converter, the first amplifier, the first filter, and the first converter. The input end of the first digital-to-analog converter is connected to the second NMOS transistor, the second data selector, the second analog-to-digital converter, and the common end of the DC power supply. The output end of the first digital-to-analog converter is also connected to the input end of the first converter. The output end of the first converter is connected to the source of the third NMOS transistor. The output end of the first converter is also connected to the input end of the first amplifier. The output end of the first amplifier is connected to the input end of the first filter. The output end of the first filter is connected to the source of the fifth NMOS transistor. The output end of the first filter is also connected to the positive input end of the second analog-to-digital converter.

8. A sensor testing method for lithium-ion batteries, characterized in that: include: Providing a lithium-ion battery sensor test chip according to any one of claims 5 to 7; measuring one of the parasitic inductance value and the electrochemical impedance spectroscopy data using the control signal; When measuring the parasitic inductance value, the switch control submodule is controlled by converting the control signal, the known voltage parameter is collected, and the parasitic inductance value is calculated according to the known voltage parameter and the standard inductance value; When measuring the electrochemical impedance spectroscopy data, the input sinusoidal wave signal is converted into an excitation current. After the excitation current flows through the lithium-ion battery, a voltage signal is obtained. The voltage signal is isolated, amplified and converted to obtain the electrochemical impedance spectroscopy data.

9. The sensor testing method for lithium-ion batteries according to claim 8, characterized in that: When measuring the parasitic inductance value, the step of controlling the switch control submodule by converting the control signal to collect the known voltage parameter includes: If the first NMOS transistor, the second NMOS transistor, and the third NMOS transistor are turned off and the fourth NMOS transistor and the fifth NMOS transistor are turned on, a first voltage value is collected, where the first voltage value is an open circuit voltage value of the lithium-ion battery; If the second NMOS transistor, the third NMOS transistor, and the fourth NMOS transistor are turned off and the first NMOS transistor and the fifth NMOS transistor are turned on, the standard capacitor is in a charging state, a second voltage value is collected, the second voltage value includes the first voltage value and a preset voltage threshold of the standard capacitor, and the preset voltage threshold of the standard capacitor is obtained by subtracting the first voltage value from the second voltage value; If the first NMOS transistor, the third NMOS transistor, and the fourth NMOS transistor are turned off and the second NMOS transistor and the fifth NMOS transistor are turned on, the standard capacitor is in a discharging state, and a third voltage value and a fourth voltage value are collected, wherein the third voltage value is the voltage value of the standard inductor, and the fourth voltage value is the sum of the first voltage value, the preset voltage threshold of the standard capacitor, and the parasitic inductor voltage.

10. The sensing test method for lithium-ion batteries according to claim 8, characterized in that: The step of obtaining electrochemical impedance spectroscopy data comprises: When the first NMOS transistor, the second NMOS transistor, the fourth NMOS transistor, and the fifth NMOS transistor are turned off and the third NMOS transistor is turned on, measuring electrochemical impedance spectroscopy data; The input sinusoidal wave signal is converted into the excitation current by the first converter, the lithium-ion battery triggers the excitation current to obtain the voltage signal, and the voltage signal is isolated, amplified and converted to obtain an electrochemical impedance spectroscopy data signal.

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