CN218995622U - Battery internal resistance parameter measuring circuit and battery internal resistance measuring device - Google Patents
Battery internal resistance parameter measuring circuit and battery internal resistance measuring device Download PDFInfo
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- CN218995622U CN218995622U CN202223326105.5U CN202223326105U CN218995622U CN 218995622 U CN218995622 U CN 218995622U CN 202223326105 U CN202223326105 U CN 202223326105U CN 218995622 U CN218995622 U CN 218995622U
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Abstract
The battery internal resistance parameter measurement circuit and the battery internal resistance measurement device comprise a current acquisition module and a voltage acquisition module which are connected to two ends of a battery pack, wherein the battery pack comprises at least a first battery unit and a second battery unit, the current acquisition module comprises a first discharge control unit, a second discharge control unit and a discharge acquisition unit, and the voltage acquisition module comprises a plurality of voltage acquisition units and a double-channel selector; the first discharge control unit is used for controlling and collecting a first sampling current, and the second discharge control unit is used for controlling and collecting a second sampling current; the first battery unit and the second battery unit respectively comprise batteries, and each battery is correspondingly connected with a voltage acquisition unit to acquire the discharge voltage drop of each battery. The circuit has high precision, simple structure and low cost, can simultaneously measure the internal resistance parameters of a plurality of batteries, and can accurately calculate the internal resistance of the plurality of batteries based on the resistance internal resistance parameters of the circuit detection.
Description
Technical Field
The present utility model relates to the field of batteries, and more particularly, to a battery internal resistance parameter measurement circuit and a battery internal resistance measurement device.
Background
In the field of mobile center or data center dynamic ring monitoring, battery state monitoring and management are very important, and accurate, reliable and effective acquisition monitoring of the voltage, internal resistance and temperature of a single battery in a battery pack for supplying power to equipment is required, because only accurate acquisition of parameters of the single battery in the battery pack is ensured, the method can provide basis for fault diagnosis and safety protection of the battery.
At present, two main acquisition modes of the internal resistance of a single battery in a battery pack of a communication power supply exist. One way is to use a power resistor to discharge a battery with a large current, and collect a voltage drop voltage generated when the battery is discharged so as to calculate the internal resistance of the battery. The disadvantage of this approach is that all the internal resistances of the cells cannot be measured simultaneously, the internal resistances of multiple cells are measured simultaneously, and the power resistor discharge has the risk of heating and causing the ignition of the cells. The other mode is to use a small resistor to discharge the battery with small current, and collect the voltage drop generated when the battery discharges so as to calculate the internal resistance of the battery. This approach has the disadvantage of requiring the use of high frequency excitation signals and high precision instrumentation amplifier components, and is therefore costly, complex in circuit configuration and inconvenient to use.
Disclosure of Invention
The utility model aims to solve the technical problems that the battery internal resistance measuring circuit in the prior art can only sample the internal resistance of a single battery or has low precision, or has the defects of high cost, complex circuit structure and unchanged application, and provides the battery internal resistance parameter measuring circuit which has high precision, simple structure and low cost and can simultaneously measure the internal resistance parameters of a plurality of batteries, and the battery internal resistance parameter measuring circuit which can accurately calculate the internal resistances of the plurality of batteries based on the resistance internal resistance parameters detected by the battery internal resistance parameter measuring circuit.
The technical scheme adopted for solving the technical problems is as follows: the method comprises the steps of constructing a battery internal resistance parameter measurement circuit, wherein the battery internal resistance parameter measurement circuit comprises a current acquisition module and a voltage acquisition module which are connected to two ends of a battery pack, the battery pack comprises at least a first battery unit and a second battery unit, the current acquisition module comprises a first discharge control unit, a second discharge control unit and a discharge acquisition unit, and the voltage acquisition module comprises a plurality of voltage acquisition units and a double-channel selector;
the first discharging control unit is connected between the first battery unit and the discharging acquisition unit to control the first battery unit to discharge and acquire a first sampling current, and the second discharging control unit is connected between the second battery unit and the discharging acquisition unit to control the second battery unit to discharge and acquire a second sampling current;
the first battery unit and the second battery unit respectively comprise batteries, and each battery is correspondingly connected with a voltage acquisition unit to acquire the discharge voltage drop of each battery.
In the battery internal resistance parameter measurement circuit, the first discharge control unit comprises an optocoupler, a first resistor, a second resistor and a first discharge switching device, wherein an anode of a transmitting end of the optocoupler is connected with an optocoupler power supply, a cathode of the transmitting end of the optocoupler is connected with a first control signal, a collector of a receiving end of the optocoupler is connected with a control end of the first discharge switching device through the second resistor, an emitter of the receiving end of the optocoupler is connected with a first end of the discharge acquisition unit, the first end of the first discharge switching device is connected with a first positive electrode of the battery pack, the second end of the first discharge switching device is connected with a second end of the discharge acquisition unit, and a control end of the first discharge switching device is further connected with the first end of the first discharge switching device through the first resistor.
In the battery internal resistance parameter measurement circuit of the present utility model, the first discharge control unit further includes a first anti-reflection switching device, a start switching device, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor, wherein the control end of the first anti-reflection switching device is connected to the first end of the start switching device through the third resistor and to the second positive electrode of the battery pack through the fourth resistor, the first end of the first anti-reflection switching device is connected to the second positive electrode of the battery pack, the second end of the first anti-reflection switching device is connected to the first end of the discharge acquisition unit, the second end of the start switching device is grounded, the third end of the start switching device is connected to the second control signal through the fifth resistor, and the sixth resistor is connected between the second end and the third end of the start switching device.
In the battery internal resistance parameter measurement circuit of the present utility model, the first discharge control unit further includes a first overcurrent protection device connected between first ends of the first discharge switching devices of the first positive electrode of the battery pack.
In the battery internal resistance parameter measurement circuit of the present utility model, the second discharge control unit includes a second discharge switching device, a control end of the second discharge switching device is connected to a third control signal, a first end of the second discharge switching device is connected to a second end of the discharge acquisition unit, and a second end of the second discharge switching device is connected to a negative electrode of the battery pack.
In the battery internal resistance parameter measurement circuit of the present utility model, the second discharge control unit further includes an anti-reflection diode, wherein an anode of the anti-reflection diode is connected to the second end of the discharge switching device, and a cathode of the anti-reflection diode is connected to a cathode of the battery pack.
In the battery internal resistance parameter measurement circuit of the present utility model, the second discharge control unit further includes a seventh resistor, an eighth resistor, and a second overcurrent protection device, the control terminal of the second discharge switching device receives the third control signal via the seventh resistor, and the eighth resistor is connected between the control terminal of the second discharge switching device and ground.
In the battery internal resistance parameter measurement circuit, the discharge acquisition unit comprises a sampling resistor and a power resistor which are sequentially connected in series between a first end and a second end of the discharge acquisition unit.
In the battery internal resistance parameter measurement circuit, each voltage acquisition unit comprises a first filter capacitor, a second filter capacitor and a filter resistor, and the dual-channel selector comprises a plurality of first input ends and a plurality of second input ends; the positive pole of the first filter capacitor is correspondingly connected with the positive pole of a battery, the negative pole is connected with the first end of the filter resistor and one first input end of the two-channel selector, the positive pole of the second filter capacitor is correspondingly connected with the positive pole of the battery, and the negative pole is connected with the second end of the filter resistor and one second input end of the two-channel selector.
The utility model solves another technical scheme adopted by the technical problem that a battery internal resistance measuring device is constructed and comprises a microcontroller and the battery internal resistance parameter measuring circuit; the microcontroller comprises a first analog-to-digital conversion channel and a second analog-to-digital conversion channel, receives the first sampling current or the second sampling current through the first analog-to-digital conversion channel, receives the discharge voltage drop of each battery through the second analog-to-digital conversion channel, and calculates the internal resistance of each battery based on the first sampling current, the second sampling current and the discharge voltage drop.
The battery internal resistance parameter measuring circuit has high precision, simple structure and low cost, and can simultaneously measure the internal resistance parameters of a plurality of batteries. Further, the battery internal resistance parameter measuring circuit can accurately calculate the internal resistances of multiple batteries based on the resistance internal resistance parameter detected by the battery internal resistance parameter measuring circuit.
Drawings
The utility model will be further described with reference to the accompanying drawings and examples, in which:
fig. 1 is a functional block diagram of a preferred embodiment of a battery internal resistance parameter measurement circuit of the present utility model;
fig. 2 is a circuit diagram of a preferred embodiment of a current collection module of the battery internal resistance parameter measurement circuit of the present utility model;
fig. 3 is a circuit diagram of a preferred embodiment of a voltage acquisition module of the battery internal resistance parameter measurement circuit of the present utility model;
fig. 4 is a functional block diagram of a preferred embodiment of the battery internal resistance measurement apparatus of the present utility model;
fig. 5 is a schematic diagram of a discharge circuit in calculation of the internal resistance of the battery.
Detailed Description
The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.
Fig. 1 is a functional block diagram of a preferred embodiment of the battery internal resistance parameter measurement circuit of the present utility model. As shown in fig. 1, the battery internal resistance parameter measurement circuit 200 of the present utility model includes a current collection module 210 and a voltage collection module 220 connected to both ends of the battery pack 100. The battery pack 100 includes at least a first battery cell 110 and a second battery cell 120. The first battery cell 110 and the second battery cell 120 preferably each include a battery. The current collection module 210 includes a first discharge control unit 211, a second discharge control unit 212, and a discharge collection unit 213, and the voltage collection module 220 includes a plurality of voltage collection units 221-224 and a dual channel selector 225. The first discharge control unit 211 is connected between the first battery cell 110 and the discharge collection unit 213 to control the first battery cell 110 to discharge and collect a first sampling current. The second discharge control unit 212 is connected between the second battery unit 120 and the discharge collection unit 213 to control the second battery unit 120 to discharge and collect a second sampling current. Each battery is correspondingly connected with a voltage acquisition unit 221 to acquire the discharge voltage drop of each battery.
In the preferred embodiment of the present utility model, the first battery cell 110 and the second battery cell 120 preferably each include at least two batteries, and thus, the voltage acquisition unit includes voltage acquisition units 221-224, and the dual channel selector 225 includes an eight channel dual selection chip. Of course, in other preferred embodiments of the present utility model, any suitable number of batteries may be selected, with each battery corresponding to one voltage acquisition unit.
In a preferred embodiment of the present utility model, the first discharge control unit 211 and the second discharge control unit 212 may perform discharge control using any suitable switching device, and the discharge collection unit 213 may include a power resistor and a sampling resistor. The voltage acquisition units 221-224 may comprise capacitive resistive filter circuits. The eight-channel double-selection chip can gate the number of battery sections to be calculated and can output the discharge voltage drop of the corresponding battery.
When the first discharging control unit 211 and the second discharging control unit 212 control the discharging of the first battery unit 110 and the second battery unit 120, respectively, the sampling currents of the two batteries may be simultaneously collected for the subsequent internal resistance detection of the batteries, respectively. Similarly, each battery is correspondingly connected with a voltage acquisition unit 221 to acquire the discharge voltage drop of each battery, so that multiple batteries can be acquired simultaneously or separately as required for subsequent battery internal resistance detection. By adopting the first discharging control unit 211 and the second discharging control unit 212 to control the discharging of the first battery unit 110 and the second battery unit 120 respectively and sharing the discharging acquisition unit 213 for sampling current acquisition, the internal resistance parameters of the batteries, that is, the discharging voltage drop, the first and the second sampling currents, can be acquired simultaneously, and a high-frequency amplifying device is not required, so that the structure is simple, the cost is low, and at the same time, high precision is possible to be ensured.
In other preferred embodiments of the present utility model, preferred circuits of the current acquisition module 210 and the voltage acquisition module 220 are further illustrated. For example, fig. 2 is a circuit diagram of a preferred embodiment of a current acquisition module of the battery internal resistance parameter measurement circuit of the present utility model. Fig. 3 is a circuit diagram of a preferred embodiment of a voltage acquisition module of the battery internal resistance parameter measurement circuit of the present utility model.
As shown in fig. 2, the first discharge control unit 211 includes an optocoupler U1, a resistor R2, a discharge fet Q1, an anti-reflection fet Q2, a start-up transistor Q6, a resistor R7, a resistor R6, a resistor R8, a resistor R9, and an overcurrent protection device F1. The second discharge control unit 212 includes a discharge field effect transistor Q3, an anti-reverse diode D1, a resistor R10, a resistor R11, and an overcurrent protection device F2. The discharge acquisition unit 213 includes a sampling resistor R5 and a power resistor R4 sequentially connected in series.
As shown in fig. 2, the anode of the transmitting end of the optocoupler U1 is connected to the optocoupler power supply vcc3.5v, the cathode of the transmitting end is connected to the first control signal PWM1, the collector of the receiving end is connected to the gate of the discharging field effect transistor Q1 through the resistor R2, and the emitter of the receiving end is connected to the first end of the sampling resistor R5. The source electrode of the discharging field effect transistor Q1 is connected to the first positive electrode v1r+ of the battery pack 100 via the overcurrent protection device F1, and the drain electrode is connected to the second end of the power resistor R4. The second end of the sampling resistor R5 is connected with the first end of the power resistor R4. The grid electrode of the discharge field effect tube Q1 is further connected with the source electrode of the discharge field effect tube Q1 through the resistor R1 in sequence.
The grid electrode of the anti-reflection field effect tube Q2 is connected with the collector electrode of the starting triode Q6 through the resistor R7 and the second positive electrode V3R+ of the battery pack 100 through the resistor R6 respectively, the source electrode of the anti-reflection field effect tube Q2 is connected with the second positive electrode V3R+ of the battery pack 100, and the drain electrode of the anti-reflection field effect tube Q2 is connected with the first end of the sampling resistor R5. The emitter of the starting triode Q6 is grounded, the base is connected with a second control signal SW_CTRL through the resistor R8, and the resistor R9 is connected between the emitter and the base of the starting triode Q6.
The grid electrode of the discharge field effect tube Q3 is connected with a third control signal through the resistor R10, the source electrode of the discharge field effect tube Q is connected with the second end of the power resistor R4, and the drain electrode of the discharge field effect tube Q is connected with the anode of the anti-reflection diode D1. The cathode of the anti-reflection diode D1 is connected to the cathode V4R-of the battery pack 100 through a current protection device F2.
In a preferred embodiment of the present utility model, the discharge fet Q1, the anti-reflection fet Q2 and the discharge fet Q3 may also be other similar switching devices, such as a triode, a relay, etc., so long as they enable the circuit to discharge normally at a certain frequency by selecting appropriate withstand voltage and through-current parameters. Any switching device known in the art may be used in the present utility model. The flow protection devices F1 and F2 may be any suitable over-current protection device, which is preferably a recoverable fuse. The power resistor R4 may be any suitable discharge resistor, and preferably a cement resistor with good heat dissipation performance is selected in a range conforming to the power range.
In a preferred embodiment of the present utility model, the first battery cell 110 is connected between the first positive electrode v1r+ and the second positive electrode v3r+ of the battery pack 100, which preferably includes a first battery cell and a second battery cell. The first discharge control unit 211 may form an upper half-bridge circuit together with the discharge collection unit 213 to perform excitation discharge on the first and second batteries to excite the voltage and/or current waveforms on the sampling resistor R5. The second battery cell 120, which preferably includes a third battery and a fourth battery, is connected between the second positive pole v3r+ and the negative pole V4R-of the battery pack 100. The second discharge control unit 212 may form a lower half-bridge circuit together with the discharge collection unit 213 to perform excitation discharge on the third and fourth batteries to excite the voltage and/or current waveforms on the sampling resistor R5. In a preferred embodiment of the present utility model, the first sampling current and the second sampling current may be collected directly by sampling a current waveform on the sampling resistor R5, or may be a voltage waveform thereof, and then the sampling current is calculated according to a resistance value of the sampling resistor R5.
In the preferred embodiment of the utility model, the overcurrent protection devices F1 and F2 are both fast recovery fuses and mainly play a role in overcurrent protection, and the discharge currents of different batteries (2V and 12V) can be respectively protected by adjusting the withstand voltage parameter and the current threshold parameter of the fast recovery fuses. Preferably, the fast recovery fuse can be tightly attached to the power resistor R4 during PCB design, when the circuit is abnormally discharged and can not be normally closed, the power resistor R4 generates heat at high temperature, and at the moment, the fast recovery fuse is subjected to high temperature, so that the discharging circuit can be disconnected, the physical protection effect is achieved, and the battery is prevented from being subjected to high Wen Qihuo. Of course, in a simplified embodiment of the present utility model, the design of the overcurrent protection devices F1 and F2 may be omitted, or other overcurrent protection devices may be used instead.
In the preferred embodiment of the utility model, the fet Q1 acts as a switching fet of the upper half-bridge discharge loop, which is frequency controlled by the optocoupler U1. The field effect transistor Q1 is preferably low in on-resistance, high in overcurrent capacity and good in heat dissipation due to the fact that larger devices are packaged. The photoelectric coupler U1 can select a device with high conversion speed and 100% -130% conversion efficiency, is low in price and can meet the precision of the utility model. Similarly, the fet Q3, which is a long-switching transistor of the lower half-bridge discharge circuit, is also preferably low in on-resistance, has a large overcurrent capability, and encapsulates a larger device, thereby facilitating heat dissipation. The field effect transistor Q3 can be directly controlled by a microcontroller, and can also be controlled by optocoupler isolation as the field effect transistor Q1.
In a preferred embodiment of the present utility model, the anti-reverse fet Q2, the start-up transistor Q6, the resistor R7, the resistor R6, the resistor R8, and the resistor R9 may together form an anti-reverse circuit of the first discharge control unit 211, which may prevent the first and second power saving Chi Zhengfu from being connected in reverse to cause damage to the internal circuit. The reverse connection preventing diode D1 forms a reverse connection preventing circuit of the second discharge control unit 212, which can prevent the internal circuit damage caused by the reverse connection between the positive and negative electrodes of the third and fourth batteries, and the reverse withstand voltage is selected to be greater than the voltage of the two batteries and accords with the current flowing capability of the loop. Of course, in a simplified embodiment of the present utility model, an anti-reverse circuit may not be provided for the first discharge control unit 211 and/or the second discharge control unit 212. In this case, the operator needs to take special care not to reverse the connection.
In the preferred embodiment of the utility model, the field effect transistor can respectively test 2V, 12V and other common batteries by adjusting the voltage and current parameters, so that the battery internal resistance parameter measuring circuit can be suitable for various 1-48V batteries.
In the preferred embodiment of the present utility model, the current collecting module adopts an upper half-bridge and lower half-bridge discharging mode, the upper half-bridge uniformly discharges the first and second batteries from the first positive pole v1r+ and the second positive pole v3r+ of the battery pack 100, and the input end to the collecting end are provided with a fast recovery fuse F1, a photoelectric coupler U1, a discharging field effect transistor Q1, a sampling resistor R5 and a power resistor R4, and an anti-reverse connection field effect transistor Q6. The fast recovery fuse F1 mainly plays a role in overcurrent protection, and the parameters of the fast recovery fuse are adjusted to respectively play a role in protecting the discharge currents of different batteries. The photoelectric coupler U1, the discharge field effect transistor Q1 and the power resistor R4 mainly conduct opening and closing of a discharge loop at a certain frequency, and discharge the first battery and the second battery to form excitation. In the preferred embodiment, the sampling resistor R5 acts as a sampling voltage generated by the flowing resistor and is sent to the microcontroller for AD acquisition, and the first sampling current, i.e., the first and second battery discharge current values, are calculated. The anti-reverse connection field effect transistor Q2 can prevent internal circuit damage caused by reverse connection of the positive and negative connection of the battery.
The lower half bridge uniformly discharges the third and fourth batteries from the second positive electrode v3r+ and the negative electrode V4R-of the battery pack 100, and a fast recovery fuse F2, a discharge field effect transistor Q3, a sampling resistor R5, a power resistor R4 and an anti-reflection diode D2 are arranged from the input end to the acquisition end. The fast recovery fuse F2 mainly plays a role in overcurrent protection, and different batteries can be protected respectively by adjusting parameters of the fast recovery fuse. The discharging field effect tube Q3 and the power resistor R4 mainly conduct opening and closing of a discharging loop at a certain frequency, and discharge the third battery and the fourth battery to form excitation. In the preferred embodiment, the sampling resistor R5 acts as a sampling voltage generated by the flowing resistor and is sent to the microcontroller for AD acquisition, and the second sampling current, i.e. the third section and the fourth section, discharge current value is calculated. The anti-reverse diode D2 can prevent the internal circuit from being damaged due to the reverse connection of the positive and negative poles of the battery.
As shown in fig. 3, each voltage acquisition unit includes a first filter capacitor, a second filter capacitor, and a filter resistor. In the preferred embodiment, the first battery unit 110 and the second battery unit 120 preferably include at least two batteries, respectively. Therefore, four voltage acquisition units are arranged corresponding to four batteries. For simplicity, only the first and fourth voltage acquisition units are shown. The first voltage acquisition unit is connected between the positive electrode V1+ and the negative electrode V1-of the first battery, and comprises filter capacitors C1 and C2 and a filter resistor R1, and the like, and the fourth voltage acquisition unit is connected between the positive electrode V4+ and the negative electrode V4-of the fourth battery, and comprises filter capacitors C7 and C8 and a filter resistor R10. The corresponding dual channel selector 225 includes four positive inputs and four negative inputs.
The positive pole of the filter capacitor C1 of the first voltage acquisition unit is correspondingly connected with the battery positive pole V1+ of the first battery, the negative pole is connected with the first end of the filter resistor R1 and is connected with the first positive pole input end of the dual-channel selector 225 through the resistor R2, the positive pole of the filter capacitor C2 is correspondingly connected with the battery negative pole V1-, the negative pole is connected with the second end of the filter resistor R1 and is connected with the first negative pole input end of the dual-channel selector 225 through the resistor R3. Similarly, the positive electrode of the filter capacitor C7 of the fourth voltage collecting unit is correspondingly connected with the positive electrode v4+ of the battery of the fourth battery, the negative electrode is connected with the fourth end of the filter resistor R10 and is connected with the fourth positive input end of the dual-channel selector 225 through the resistor R11, the positive electrode of the filter capacitor C8 is correspondingly connected with the negative electrode V4-, the negative electrode of the battery of the fourth battery is connected with the second end of the filter resistor R10 and is connected with the fourth negative input end of the dual-channel selector 225 through the resistor R12. The second and third voltage detection units are connected to the second and third batteries in a similar manner, and will not be described in detail.
In the preferred embodiment of the present utility model, each voltage acquisition unit includes a high-pass filter circuit composed of two filter capacitors and filter resistors for battery voltage, and a two-channel selector 225 composed of a two-channel gating chip U2 for battery voltage, which can gate the number of battery segments to be calculated, so as to output the battery voltage of the corresponding battery, i.e. obtain the discharge voltage drop of each battery.
The filter capacitor can be selected to be an in-line electrolytic capacitor meeting the requirements of voltage resistance and capacitance, the two-channel selector can be a common gating chip, and one group is selected by four groups of two channels.
The voltage input interface of the battery internal resistance parameter measuring circuit has an overcurrent protection function, can measure internal resistances of multiple batteries of 1V-48V simultaneously, has a circuit high-temperature protection function, and can automatically cut off a measuring loop when the temperature of the internal discharge resistor of the module is too high, so that the power temperature is prevented from continuously rising. The battery internal resistance parameter measurement circuit has the advantages of high precision, simple structure, low cost, strong common mode interference resistance, high response speed and high instantaneity.
Fig. 4 is a functional block diagram of a preferred embodiment of the battery internal resistance measuring apparatus of the present utility model, which performs calculation of the battery internal resistance using the parameters obtained by the battery internal resistance parameter measuring circuit shown in fig. 1 to 3. As shown in fig. 4, the battery internal resistance measuring apparatus includes a microcontroller 300 and the aforementioned battery internal resistance parameter measuring circuit 200. The battery internal resistance parameter measurement circuit includes a current collection module 210 and a voltage collection module 220 connected across the battery pack 100 as previously described. The microcontroller 300 includes an a/D channel 1 and an a/D channel 2, the microcontroller 300 receives the first sampling current or the second sampling current through the a/D channel 1, receives a discharge voltage drop of each battery through the a/D channel 2, and calculates an internal resistance of each battery based on the first sampling current, the second sampling current, and the discharge voltage drop. The specific calculation process and principle thereof can refer to the calculation process of a single cell in the prior art, and will be briefly described below by taking fig. 5 as an example.
The above description of the discharge of the half-bridge battery (i.e., the first and second batteries) shows that the resistance value of the sampling resistor R5 is RCAL. Wherein the upper half-bridge battery discharge drop voltage vb= (v1r+) - (v3r+); and the sampling resistor voltage vcal= (vs+) - (VS-) of the sampling resistor R5. Thus, the sampling current i=vcal/RCAL flowing through the sampling resistor R5. Assuming that the impedance of the battery is Zi, vb/zi=i=vcal/RCAL, since the currents flowing through the whole loop are equal; so zi= (Vb/VCAL) RCAL. And Vb is the discharge voltage drop of the battery with the corresponding number of sections acquired by the voltage acquisition module. I.e., if Zi represents the internal resistance of the first cell, vb gates the discharge voltage drop of the first cell obtained by the first voltage sampling unit for the two-channel selector 225. If Zi represents the internal resistance of the second cell, then Vb gates the discharge voltage drop of the second cell obtained by the second voltage sampling unit for the dual channel selector 225. The discharging process of the lower half-bridge battery is also similar and is not described here.
Therefore, the battery internal resistance measuring device can measure the internal resistances of a plurality of batteries at one time, has high measuring speed, and has fewer external detection cables, and is simple and convenient to install. The battery internal resistance measuring device has high-temperature protection performance, high measuring precision and low cost, an input overcurrent protection circuit is designed, the device has strong anti-interference performance, and the device is simple in circuit structure, high in protection performance, high in measuring precision, good in reliability, strong in anti-interference capability, convenient to use and low in cost.
While the utility model has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the utility model. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the utility model without departing from its scope. Therefore, it is intended that the utility model not be limited to the particular embodiment disclosed, but that the utility model will include all embodiments falling within the scope of the appended claims.
The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the utility model.
Claims (10)
1. The battery internal resistance parameter measurement circuit is characterized by comprising a current acquisition module and a voltage acquisition module which are connected to two ends of a battery pack, wherein the battery pack comprises at least a first battery unit and a second battery unit, the current acquisition module comprises a first discharge control unit, a second discharge control unit and a discharge acquisition unit, and the voltage acquisition module comprises a plurality of voltage acquisition units and a double-channel selector;
the first discharging control unit is connected between the first battery unit and the discharging acquisition unit to control the first battery unit to discharge and acquire a first sampling current, and the second discharging control unit is connected between the second battery unit and the discharging acquisition unit to control the second battery unit to discharge and acquire a second sampling current;
the first battery unit and the second battery unit respectively comprise batteries, and each battery is correspondingly connected with a voltage acquisition unit to acquire the discharge voltage drop of each battery.
2. The battery internal resistance parameter measurement circuit according to claim 1, wherein the first discharge control unit comprises an optocoupler, a first resistor, a second resistor and a first discharge switching device, a transmitting end anode of the optocoupler is connected with an optocoupler power supply, a transmitting end cathode is connected with a first control signal, a receiving end collector is connected with a control end of the first discharge switching device through the second resistor, a receiving end emitter is connected with a first end of the discharge collecting unit, a first end of the first discharge switching device is connected with a first positive electrode of the battery pack, a second end of the first discharge switching device is connected with a second end of the discharge collecting unit, and a control end of the first discharge switching device is further connected with a first end of the first discharge switching device through the first resistor.
3. The battery internal resistance parameter measurement circuit according to claim 2, wherein the first discharge control unit further comprises a first anti-reflection switching device, a start switching device, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor, wherein a control end of the first anti-reflection switching device is connected with a first end of the start switching device and a second positive electrode of the battery pack through the fourth resistor respectively, a first end of the first anti-reflection switching device is connected with the second positive electrode of the battery pack, a second end of the first anti-reflection switching device is connected with the first end of the discharge acquisition unit, a second end of the start switching device is grounded, a third end of the start switching device is connected with a second control signal through the fifth resistor, and the sixth resistor is connected between the second end and the third end of the start switching device.
4. The battery internal resistance parameter measurement circuit according to claim 3, wherein the first discharge control unit further includes a first overcurrent protection device connected between first ends of the first discharge switching devices of the first positive electrode of the battery pack.
5. The battery internal resistance parameter measurement circuit according to claim 1, wherein the second discharge control unit comprises a second discharge switching device, a control end of the second discharge switching device is connected with a third control signal, a first end of the second discharge switching device is connected with a second end of the discharge acquisition unit, and a second end of the second discharge switching device is connected with a negative electrode of the battery pack.
6. The battery internal resistance parameter measurement circuit according to claim 5, wherein the second discharge control unit further comprises an anti-reflection diode having an anode connected to the second terminal of the discharge switching device and a cathode connected to the negative electrode of the battery pack.
7. The battery internal resistance parameter measurement circuit according to claim 6, wherein the second discharge control unit further includes a seventh resistor, an eighth resistor, and a second overcurrent protection device, the control terminal of the second discharge switching device receiving the third control signal via the seventh resistor, the eighth resistor being connected between the control terminal of the second discharge switching device and ground.
8. The battery internal resistance parameter measurement circuit of any one of claims 1-7, wherein the discharge acquisition unit comprises a sampling resistor and a power resistor serially connected in sequence between a first end and a second end of the discharge acquisition unit.
9. The battery internal resistance parameter measurement circuit according to any one of claims 1 to 7, wherein each voltage acquisition unit includes a first filter capacitor, a second filter capacitor, and a filter resistor, and the two-channel selector includes a plurality of first input terminals and a plurality of second input terminals; the positive pole of the first filter capacitor is correspondingly connected with the positive pole of a battery, the negative pole is connected with the first end of the filter resistor and one first input end of the two-channel selector, the positive pole of the second filter capacitor is correspondingly connected with the positive pole of the battery, and the negative pole is connected with the second end of the filter resistor and one second input end of the two-channel selector.
10. A battery internal resistance measurement device, characterized by comprising a microcontroller and a battery internal resistance parameter measurement circuit according to any one of claims 1-9; the microcontroller comprises a first analog-to-digital conversion channel and a second analog-to-digital conversion channel, receives the first sampling current or the second sampling current through the first analog-to-digital conversion channel, receives the discharge voltage drop of each battery through the second analog-to-digital conversion channel, and calculates the internal resistance of each battery based on the first sampling current, the second sampling current and the discharge voltage drop.
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| CN202223326105.5U CN218995622U (en) | 2022-12-09 | 2022-12-09 | Battery internal resistance parameter measuring circuit and battery internal resistance measuring device |
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| CN202223326105.5U CN218995622U (en) | 2022-12-09 | 2022-12-09 | Battery internal resistance parameter measuring circuit and battery internal resistance measuring device |
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