Lithium battery measuring circuit and lithium battery system

Abstract

The utility model provides a lithium battery measuring circuit and a lithium battery system, a lithium battery comprises a plurality of battery cells connected in series, and the lithium battery measuring circuit comprises a detection chip which comprises a voltage dividing device, a plurality of first switching devices, a plurality of voltage detection ports and a plurality of voltage sampling circuits, the first ends of the voltage detection ports are electrically connected with the first ends of the first switching devices in a one-to-one correspondence mode, the second ends of the multiple first switching devices are electrically connected with the first end of the voltage dividing device, the control ends of the first switching devices are used for receiving high and low level signals, and the second end of the voltage dividing device is grounded. The input ends of the voltage sampling circuits are electrically connected with the first ends of the voltage detection ports in a one-to-one correspondence manner; the first ends of the thermistors are electrically connected with the second ends of the voltage detection ports, the second ends of the thermistors are used for being electrically connected with the positive electrodes of the battery cells in a one-to-one correspondence mode when the voltage detection is carried out on the battery cells, and the second ends of the thermistors are suspended and attached to the battery cells when the temperature detection is carried out on the battery cells.

Description

Technical Field

[0001] The present application relates to the technical field of lithium battery protection, and in particular to a lithium battery measurement circuit and a lithium battery system. Background Art

[0002] At present, the voltage sampling and temperature sampling in the chip of the lithium battery measurement circuit require separate leads. The more batteries are connected in series, the more voltage and temperature sampling lines are required, which is not conducive to the miniaturization of the chip design. In addition, the more sampling lines there are, the more complicated the overall routing of the lithium battery measurement circuit is, and the higher the design cost is. Utility Model Content

[0003] The main purpose of the present application is to provide a lithium battery measurement circuit and a lithium battery system to solve the problem that the lithium battery measurement circuit in the prior art is difficult to miniaturize.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a measurement circuit of a lithium battery is provided, wherein the lithium battery comprises a plurality of battery cells connected in series, and the measurement circuit of the lithium battery comprises: a detection chip, comprising a voltage divider device, a plurality of three-terminal first switch devices, a plurality of voltage detection ports, and a plurality of voltage sampling circuits, wherein the first end of the voltage detection port is electrically connected to the first end of the first switch device in a one-to-one correspondence, the second ends of the plurality of first switch devices are electrically connected to the first end of the voltage divider device, the control end of the first switch device is used to receive high and low level signals, the second end of the voltage divider device is grounded, and the input end of the voltage sampling circuit is electrically connected to the first end of the voltage detection port in a one-to-one correspondence; a plurality of thermistors, wherein the first ends of the thermistors are electrically connected to the second ends of the voltage detection ports in a one-to-one correspondence, when voltage detection is performed on the battery cells, the second ends of the thermistors are used to be electrically connected to the positive electrodes of the battery cells in a one-to-one correspondence, and when temperature detection is performed on the battery cells, the second ends of the thermistors are not electrically connected to the battery cells and the thermistors are located on one side of the battery cells.

[0005] Optionally, the detection chip further includes: a plurality of first current limiting devices, and the first ends of the voltage detection ports are electrically connected to the first ends of the first switch devices through the first current limiting devices in a one-to-one correspondence.

[0006] Optionally, the measurement circuit of the lithium battery further includes: a plurality of first filter structures, wherein the first filter structures are electrically connected to first ends of two adjacent thermistors.

[0007] Optionally, the measurement circuit of the lithium battery also includes a three-terminal second switch device and a third switch device, the detection chip also includes a charging status indication signal output terminal and a discharging status indication signal output terminal, the first end of the second switch device is used to be electrically connected to a load or a power supply, the second end of the second switch device is electrically connected to the first end of the third switch device, the second end of the third switch device is electrically connected to the positive electrode of the lithium battery, the charging status indication signal output terminal is electrically connected to the control end of the second switch device, and the discharging status indication signal output terminal is electrically connected to the control end of the third switch device.

[0008] Optionally, the measurement circuit of the lithium battery also includes a second current limiting device, a third current limiting device, a fourth current limiting device and a second filtering structure, the charging status indication signal output end is electrically connected to the control end of the second switching device through the second current limiting device, the discharge status indication signal output end is electrically connected to the control end of the third switching device through the third current limiting device, the first end of the second filtering structure is electrically connected to the second end of the second switching device through the fourth current limiting device, and the second end of the second filtering structure is grounded.

[0009] Optionally, the second current limiting device, the third current limiting device and the fourth current limiting device respectively include resistors, and the second filtering structure includes a plurality of capacitors connected in series.

[0010] Optionally, the first current limiting device includes a resistor.

[0011] Optionally, the first filtering structure includes a capacitor.

[0012] Optionally, the voltage divider device includes a resistor, and the first switch device includes a MOS tube.

[0013] According to another aspect of the present application, a lithium battery system is provided, comprising: a lithium battery, comprising a plurality of battery cells connected in series, the positive electrode of the battery cell at the head of the series connection being the positive electrode of the lithium battery, and the negative electrode of the battery cell at the tail of the series connection being the negative electrode of the lithium battery; and a measurement circuit for any one of the lithium batteries described above.

[0014] By applying the technical solution of the present application, when it is necessary to perform voltage detection on the battery cell to be tested, the second end of the thermistor is electrically connected to the positive electrode of the battery cell to be tested, so that the voltage sampling circuit is electrically connected to the battery cell to be tested through the thermistor, and the first switch device is controlled to be disconnected through high and low level signals, so that the voltage sampling circuit collects the voltage value of the voltage detection port, and the voltage value is the voltage value of the battery cell to be tested; when it is necessary to perform temperature detection on the battery cell to be tested, the second end of the thermistor is not electrically connected to the positive electrode of the battery cell to be tested, and the first switch device is controlled to be closed through high and low level signals, thereby conducting the loop from the battery cell to be tested, the thermistor, the first switch device, and the voltage divider device to the ground, and then the voltage sampling circuit collects the voltage value. The voltage value of the voltage divider device is determined according to the voltage value of the voltage divider device, the voltage value of the battery cell to be tested, and the resistance value of the voltage divider device, so as to obtain the temperature value measured by the thermistor and the temperature of the battery cell to be tested. Therefore, the present application realizes the detection of the two parameters of the voltage and temperature of the lithium battery cell through the voltage detection port, that is, the voltage electrical measurement and temperature detection of the lithium battery cell reuse the voltage detection port. Compared with the method in the prior art where the voltage and temperature sampling in the detection chip of the lithium battery measurement circuit need to be set separately, the voltage and temperature sampling ports of the detection chip of the present application are reduced by half, and the chip package size is reduced, thereby realizing the miniaturization of the lithium battery measurement circuit. In addition, due to the reduction of the sampling ports of the detection chip in the measurement circuit of the lithium battery, the overall wiring complexity of the lithium battery measurement circuit is reduced, the IC (Integrated Circuit) board layer design is reduced, and the design cost of the lithium battery measurement circuit is optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 A schematic diagram of the structure of a lithium battery measurement circuit according to an embodiment of the present application is shown;

[0017] Figure 2 A specific structural schematic diagram of a lithium battery measurement circuit according to an embodiment of the present application is shown.

[0018] The above drawings include the following reference numerals:

[0019] 12. Battery cell; 13. Detection chip; 14. Voltage divider; 15. First switch device; 16. Voltage detection port; 17. Voltage sampling circuit; 18. Thermistor; 19. First current limiting device; 20. First filtering structure; 21. Second switch device; 22. Third switch device; 23. Charging status indication signal output terminal; 24. Discharging status indication signal output terminal; 25. Load or power supply; 26. Second current limiting device; 27. Third current limiting device; 28. Fourth current limiting device; 29. ​​Second filtering structure; 30. Third filtering structure. DETAILED DESCRIPTION

[0020] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0021] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0022] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be intermediate elements. Moreover, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element through a third element.

[0023] As introduced in the background technology, it is difficult to miniaturize the measurement circuit of a lithium battery in the prior art. In order to solve the above technical problems, the present application proposes a measurement circuit of a lithium battery and a lithium battery system.

[0024] According to one aspect of the present application, a measurement circuit for a lithium battery is provided, such as Figure 1 As shown, the lithium battery includes a plurality of battery cells 12 connected in series, and the measurement circuit of the lithium battery includes:

[0025] A detection chip 13, comprising a voltage divider device 14, a plurality of three-terminal first switch devices 15, a plurality of voltage detection ports 16 and a plurality of voltage sampling circuits 17, wherein the first end of the voltage detection port 16 is electrically connected to the first end of the first switch device 15 in a one-to-one correspondence, the second ends of the plurality of first switch devices 15 are electrically connected to the first end of the voltage divider device 14, the control end of the first switch device 15 is used to receive high and low level signals, the second end of the voltage divider device 14 is grounded, and the input end of the voltage sampling circuit 17 is electrically connected to the first end of the voltage detection port 16 in a one-to-one correspondence;

[0026] Specifically, the voltage detection port is both the voltage sampling port of the detection chip and the temperature sampling port of the detection chip. The control end of the first switch device, i.e., the sampling switch of the measurement circuit of the lithium battery, realizes the conduction or shutdown of the first switch device by receiving high and low level signals. The voltage sampling circuit is used to sample the voltage value of the first end of the voltage detection port. Those skilled in the art can flexibly set the circuit structure of the voltage sampling circuit according to actual design needs, and this application does not impose specific restrictions on this.

[0027] A plurality of thermistors 18, wherein the first ends of the thermistors 18 are electrically connected to the second ends of the voltage detection ports 16 in a one-to-one correspondence, and when voltage detection is performed on the battery cell 12, the second ends of the thermistors 18 are used to be electrically connected to the positive electrodes of the battery cells 12 in a one-to-one correspondence, and when temperature detection is performed on the battery cell 12, the second ends of the thermistors 18 are not electrically connected to the battery cell 12 and the thermistors 18 are located on one side of the battery cell.

[0028] Specifically, when voltage detection is performed on the battery cell, the thermistor is electrically connected to the battery cell to be detected, while when temperature detection is performed on the battery cell, the thermistor does not need to be electrically connected to the battery cell to be detected, but only needs to be close to the battery cell to be detected. When temperature detection is performed, the distance between the thermistor and the battery cell to be detected can be flexibly set according to actual needs, as long as the detection distance of the thermistor is met.

[0029] In the described embodiment, the first end of the first switching device of the three terminals is electrically connected to the first end of the voltage detection port, the second end of the first switching device is grounded through a voltage divider device, the control end of the first switching device is used to receive high and low level signals, the first end of the voltage detection port of the detection chip is electrically connected to the voltage sampling circuit, and the second end is electrically connected to the first end of the thermistor, the thermistor is located on one side of the battery cell to be tested, and the second end of the thermistor is electrically connected or not connected to the positive electrode of the battery cell to be tested. In the case where voltage detection is required for the battery cell to be tested, the second end of the thermistor is electrically connected to the positive electrode of the battery cell to be tested, so that the voltage sampling circuit is electrically connected to the battery cell to be tested through the thermistor, and the first switch device is controlled to be disconnected through high and low level signals, so that the voltage sampling circuit collects the voltage value of the voltage detection port, and the voltage value is the voltage value of the battery cell to be tested; in the case where temperature detection is required for the battery cell to be tested, the second end of the thermistor is not electrically connected to the positive electrode of the battery cell to be tested, and the first switch device is controlled to be closed through high and low level signals, thereby conducting the loop from the battery cell to be tested, the thermistor, the first switch device, and the voltage divider device to the ground, and then the voltage sampling circuit collects the voltage value of the voltage divider device The voltage value of the voltage divider device, the voltage value of the battery cell to be tested, and the resistance value of the voltage divider device are used to determine the current resistance value of the thermistor, thereby obtaining the temperature value measured by the thermistor and the temperature of the battery cell to be tested. Therefore, the present application realizes the detection of the two parameters of the voltage and temperature of the lithium battery cell through the voltage detection port, that is, the voltage electrical measurement and temperature detection of the lithium battery cell reuse the voltage detection port. Compared with the method in the prior art where the voltage and temperature sampling in the detection chip of the lithium battery measurement circuit need to be set separately, the voltage and temperature sampling ports of the detection chip of the present application are reduced by half, and the chip package size is reduced, thereby realizing the miniaturization of the lithium battery measurement circuit. In addition, due to the reduction of the sampling ports of the detection chip in the lithium battery measurement circuit, the overall wiring complexity of the lithium battery measurement circuit is reduced, the IC board layer design is reduced, and the design cost of the lithium battery measurement circuit is optimized.

[0030] Specifically, the first switch device can be any suitable three-terminal switch device in the prior art, such as MOS (Metal-Oxide-Semiconductor Field-Effect Transistor, Metal Oxide Semiconductor Field Effect Transistor) tube, triode and thyristor. Those skilled in the art can flexibly select according to actual needs. In addition, the types of multiple first switch devices can be the same or different. In order to further simplify the design cost of the measurement circuit of the lithium battery, in one embodiment of the present application, the types of multiple first switch devices are the same, such as all using MOS tubes, or all sampling triodes. In the present application, multiple first switch devices are all MOS tubes.

[0031] Taking the first switch device as a MOS tube as an example, when the first switch device is an NMOS (N-type MOS tube) and the first switch device needs to be turned on, a high-level signal needs to be provided to its control end; when the first switch device is an NMOS and the first switch device needs to be turned off, a low-level signal needs to be provided to its control end. When the first switch device is a PMOS (P-type MOS tube) and the first switch device needs to be turned on, a low-level signal needs to be provided to its control end; when the first switch device is a PMOS and the first switch device needs to be turned off, a high-level signal needs to be provided to its control end. The control logic of other types of first switch tubes is similar, and this application will not repeat it.

[0032] Optionally, the voltage divider device includes a resistor. For example, the voltage divider device may be a resistor, or may be a plurality of resistors connected in series or in parallel. Of course, in addition to the resistor, other voltage divider elements may be selected as the voltage divider device in the art, such as a voltage stabilizer, a capacitor, and an inductor.

[0033] In actual application, multiple voltage sampling circuits 17 can be integrated into a voltage sampling structure, or Figure 1 The structure shown is a plurality of discrete voltage sampling circuits 17 .

[0034] In order to further ensure the safety and reliability of the lithium battery measurement circuit, in an optional embodiment, as Figure 2 As shown, the detection chip further includes: a plurality of first current limiting devices 19, and the first ends of the voltage detection ports 16 are electrically connected to the first ends of the first switch devices through the first current limiting devices 19. The first current limiting resistor is used to limit the current value in the loop to prevent other electronic components connected in series from being burned out due to a large current, thereby further ensuring the high reliability of the lithium battery measurement circuit.

[0035] Specifically, Figure 2As shown, when the first switch device 15 is disconnected, the loop from the voltage detection port 16 to the ground through the first current limiting device 19, the first switch device 15, and the voltage divider device 14 is disconnected; and when the first switch device 15 is closed, the loop from the voltage detection port 16 to the ground through the first current limiting device 19, the first switch device 15, and the voltage divider device 14 is connected, and the voltage value sampled by the voltage sampling circuit 17 is the voltage value of both the first current limiting device 19 and the voltage divider device 14. The current on the loop can be obtained according to the voltage value, the resistance value of the first current limiting device 19 and the voltage divider device 14, and then the voltage across the thermistor is determined according to the voltage value of the battery cell to be tested and the voltage value, which is the difference between the two voltage values. The current resistance value of the thermistor can be obtained according to the voltage difference and the current value.

[0036] Further, the first current limiting device may include any suitable current limiting element, such as a diode, a resistor, a MOS tube, and a thyristor. In another exemplary embodiment of the present application, the first current limiting device includes a resistor. For example, the first current limiting device may be a resistor or a plurality of resistors connected in series and parallel.

[0037] In another optional solution of the present application, Figure 2 As shown, the measurement circuit of the lithium battery further includes: a plurality of first filter structures 20, and the first filter structures 20 are electrically connected to the first ends of two adjacent thermistors 18. That is, the number of the first filter structures 20 is one less than the number of the thermistors 18, and the plurality of the first filter structures 20 are electrically connected to the two adjacent thermistors 18 in sequence, thereby achieving a filtering effect.

[0038] In the actual application process, those skilled in the art can flexibly set the specific component structure of the first filtering structure according to actual needs. The first filtering structure includes a capacitor. Of course, in addition to the capacitor, the first filtering structure can also be other filtering circuits, such as an inductor, an R (resistance) C (capacitance) filtering circuit, etc. Specifically, Figure 2 Said first filtering structure is a capacitor.

[0039] Specifically, Figure 1 and Figure 2As shown, the measurement circuit of the lithium battery also includes a three-terminal second switch device 21 and a third switch device 22, and the detection chip also includes a charging status indication signal output terminal 23 and a discharging status indication signal output terminal 24, the first end of the second switch device 21 is used to be electrically connected to a load or a power supply 25, the second end of the second switch device 21 is electrically connected to the first end of the third switch device 22, and the second end of the third switch device 22 is electrically connected to the positive electrode of the lithium battery, wherein the positive electrode of the lithium battery is the positive electrode of the battery cell 12 located at the head of the series connection among multiple battery cells 12 connected in series, the charging status indication signal output terminal 23 is electrically connected to the control end of the second switch device 21, and the discharging status indication signal output terminal 24 is electrically connected to the control end of the third switch device 22. When the lithium battery is electrically connected to a power source through the second switch device and the third switch device connected in series and overcharge occurs, the detection chip can output an overcharge indication signal through the charging state indication signal output terminal to disconnect the second switch device, thereby disconnecting the connection between the lithium battery and the power source, thereby protecting the lithium battery from overcharge; when the lithium battery is electrically connected to a load through the second switch device and the third switch device connected in series and overdischarge occurs, the detection chip can output an overdischarge indication signal through the discharge state indication signal output terminal to disconnect the third switch device, thereby disconnecting the connection between the lithium battery and the load, thereby protecting the lithium battery from overdischarge.

[0040] Among them, the overcharge detection module structure connected to the charging status indication signal output terminal 23 in the detection chip and the over-discharge detection module structure connected to the discharge status indication signal output terminal in the detection chip are both structures in the prior art, and this application no longer describes the specific structures of the overcharge detection module and the over-discharge detection module in the detection chip.

[0041] In order to further ensure the reliability of the measurement circuit of the lithium battery, according to some optional embodiments of the present application, Figure 2As shown, the measurement circuit of the lithium battery further includes a second current limiting device 26, a third current limiting device 27, a fourth current limiting device 28 and a second filtering structure 29, the charging state indication signal output end 23 is electrically connected to the control end of the second switch device 21 through the second current limiting device 26, the discharging state indication signal output end 24 is electrically connected to the control end of the third switch device 22 through the third current limiting device 27, the first end of the second filtering structure 29 is electrically connected to the second end of the second switch device 21 through the fourth current limiting device 28, and the second end of the second filtering structure 29 is grounded. The second current limiting device, the third current limiting device and the fourth current limiting device are used to limit the current size on the corresponding loop, and the second filtering structure is used to eliminate the surge on the loop where it is located.

[0042] In actual application, the second current limiting device, the third current limiting device and the fourth current limiting device can be any suitable current limiting element, such as a resistor, a diode, an inductor, etc. In a specific embodiment, the second current limiting device, the third current limiting device and the fourth current limiting device respectively include a resistor. More specifically, Figure 2 As shown, the second current limiting device, the third current limiting device and the fourth current limiting device are all resistors.

[0043] Likewise, the second filtering structure may also be any suitable filtering element or filtering circuit. In the present application, the second filtering structure includes a plurality of capacitors connected in series.

[0044] like Figure 2 As shown, the measurement circuit of the lithium battery also includes a third filtering structure 30, a first end of the third filtering structure 30 is electrically connected to the positive electrode of the battery cell 12 located at the tail of the series connection of the lithium battery, and a second end of the third filtering structure 30 is electrically connected to the negative electrode of the battery cell 12 located at the tail for filtering.

[0045] The third filtering structure may be any suitable filtering element or filtering circuit. In the present application, the second filtering structure includes a capacitor, specifically a capacitor.

[0046] It should be noted that the Figure 1 and Figure 2 The measurement circuit of a 4-string lithium battery is exemplarily shown, that is, there are 4 thermistors, but the embodiments of the present application are not limited to the measurement circuit of a 4-string lithium battery, and can also be applied to the measurement circuit of a multi-string lithium battery with other numbers.

[0047] In actual application, the detection chip of the present application may specifically be a BQ40Z50 / SH366006 chip.

[0048] According to another aspect of the present application, a lithium battery system is provided, comprising: a lithium battery, comprising a plurality of battery cells connected in series, the positive electrode of the battery cell at the head of the series connection being the positive electrode of the lithium battery, and the negative electrode of the battery cell at the tail of the series connection being the negative electrode of the lithium battery; and a measurement circuit for any one of the lithium batteries described above.

[0049] The lithium battery system described in the present application includes a lithium battery and a measurement circuit of the lithium battery. When it is necessary to perform voltage detection on a cell to be tested of the lithium battery, the second end of the thermistor in the measurement circuit is electrically connected to the positive electrode of the cell to be tested, so that the voltage sampling circuit is electrically connected to the cell to be tested through the thermistor, and the first switch device is controlled to be disconnected through high and low level signals, so that the voltage sampling circuit collects the voltage value of the voltage detection port, and the voltage value is the voltage value of the cell to be tested; when it is necessary to perform temperature detection on the cell to be tested, the second end of the thermistor is not electrically connected to the positive electrode of the cell to be tested, and the first switch device is controlled to be closed through high and low level signals, so that A loop is connected between the battery cell to be tested, the thermistor, the first switching device, and the voltage divider device to the ground, and then the voltage value of the voltage divider device is collected through a voltage sampling circuit. According to the voltage value of the voltage divider device, the voltage value of the battery cell to be tested and the resistance value of the voltage divider device, the current resistance value of the thermistor is determined, thereby obtaining the temperature value measured by the thermistor and the temperature of the battery cell to be tested. Therefore, the present application realizes the detection of the two parameters of the voltage and temperature of the lithium battery cell through the voltage detection port, that is, the voltage electrical measurement and temperature detection of the lithium battery cell reuse the voltage detection port, thereby realizing the miniaturization of the lithium battery measurement circuit and reducing the overall wiring complexity of the lithium battery measurement circuit.

[0050] From the above description, it can be seen that the embodiments described in this application achieve the following technical effects:

[0051] 1) In the measurement circuit of the lithium battery of the present application, the first end of the first switching device of the three terminals is electrically connected to the first end of the voltage detection port, the second end of the first switching device is grounded through a voltage divider device, the control end of the first switching device is used to receive high and low level signals, the first end of the voltage detection port of the detection chip is electrically connected to the voltage sampling circuit, and the second end is electrically connected to the first end of the thermistor, the thermistor is located on one side of the battery cell to be tested, and the second end of the thermistor is electrically connected to or not connected to the positive electrode of the battery cell to be tested. In the case where voltage detection is required for the battery cell to be tested, the second end of the thermistor is electrically connected to the positive electrode of the battery cell to be tested, so that the voltage sampling circuit is electrically connected to the battery cell to be tested through the thermistor, and the first switch device is controlled to be disconnected through high and low level signals, so that the voltage sampling circuit collects the voltage value of the voltage detection port, and the voltage value is the voltage value of the battery cell to be tested; in the case where temperature detection is required for the battery cell to be tested, the second end of the thermistor is not electrically connected to the positive electrode of the battery cell to be tested, and the first switch device is controlled to be closed through high and low level signals, thereby conducting the loop from the battery cell to be tested, the thermistor, the first switch device, and the voltage divider device to the ground, and then the voltage sampling circuit collects the voltage value of the voltage divider device The voltage value of the voltage divider device, the voltage value of the battery cell to be tested, and the resistance value of the voltage divider device are used to determine the current resistance value of the thermistor, thereby obtaining the temperature value measured by the thermistor and the temperature of the battery cell to be tested. Therefore, the present application realizes the detection of the two parameters of the voltage and temperature of the lithium battery cell through the voltage detection port, that is, the voltage electrical measurement and temperature detection of the lithium battery cell reuse the voltage detection port. Compared with the method in the prior art where the voltage and temperature sampling in the detection chip of the lithium battery measurement circuit need to be separately set up, the voltage and temperature sampling ports of the detection chip of the present application are reduced by half, and the chip package size is reduced, thereby realizing the miniaturization of the lithium battery measurement circuit. In addition, due to the reduction of the sampling ports of the detection chip in the measurement circuit of the lithium battery, the overall wiring complexity of the lithium battery measurement circuit is reduced, the IC (Integrated Circuit) board layer design is reduced, and the design cost of the lithium battery measurement circuit is optimized.

[0052] 2) The lithium battery system described in the present application includes a lithium battery and a measurement circuit of the lithium battery. When it is necessary to perform voltage detection on a cell to be tested of the lithium battery, the second end of the thermistor in the measurement circuit is electrically connected to the positive electrode of the cell to be tested, so that the voltage sampling circuit is electrically connected to the cell to be tested through the thermistor, and the first switch device is controlled to be disconnected through high and low level signals, so that the voltage sampling circuit collects the voltage value of the voltage detection port, and the voltage value is the voltage value of the cell to be tested; when it is necessary to perform temperature detection on the cell to be tested, the second end of the thermistor is not electrically connected to the positive electrode of the cell to be tested, and the first switch device is controlled to be closed through high and low level signals, so that the voltage sampling circuit collects the voltage value of the voltage detection port, and the voltage value is the voltage value of the cell to be tested; when it is necessary to perform temperature detection on the cell to be tested, the second end of the thermistor is not electrically connected to the positive electrode of the cell to be tested, and the first switch device is controlled to be closed through high and low level signals, so that A loop is conducted between the battery cell to be tested, the thermistor, the first switching device, and the voltage divider device to the ground, and the voltage value of the voltage divider device is collected through a voltage sampling circuit. The current resistance value of the thermistor is determined according to the voltage value of the voltage divider device, the voltage value of the battery cell to be tested, and the resistance value of the voltage divider device, thereby obtaining the temperature value measured by the thermistor and the temperature of the battery cell to be tested. Therefore, the present application realizes the detection of the two parameters of the voltage and temperature of the lithium battery cell through the voltage detection port, that is, the voltage electrical measurement and temperature detection of the lithium battery cell reuse the voltage detection port, thereby realizing the miniaturization of the lithium battery measurement circuit and reducing the overall wiring complexity of the lithium battery measurement circuit.

[0053] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A measurement circuit for a lithium battery, the lithium battery comprising a plurality of cells connected in series, characterized in that: The measuring circuit of the lithium battery comprises: A detection chip, comprising a voltage divider device, a plurality of three-terminal first switch devices, a plurality of voltage detection ports, and a plurality of voltage sampling circuits, wherein the first end of the voltage detection port is electrically connected to the first end of the first switch device in a one-to-one correspondence, the second ends of the plurality of first switch devices are electrically connected to the first end of the voltage divider device, the control end of the first switch device is used to receive high and low level signals, the second end of the voltage divider device is grounded, and the input end of the voltage sampling circuit is electrically connected to the first end of the voltage detection port in a one-to-one correspondence; A plurality of thermistors, wherein the first ends of the thermistors are electrically connected to the second ends of the voltage detection ports in a one-to-one correspondence, and when voltage detection is performed on the battery cells, the second ends of the thermistors are used to be electrically connected to the positive electrodes of the battery cells in a one-to-one correspondence, and when temperature detection is performed on the battery cells, the second ends of the thermistors are not electrically connected to the battery cells and the thermistors are located on one side of the battery cells.

2. The lithium battery measurement circuit according to claim 1, characterized in that: The detection chip also includes: A plurality of first current limiting devices, wherein the first ends of the voltage detection ports are electrically connected to the first ends of the first switch devices through the first current limiting devices in a one-to-one correspondence.

3. The lithium battery measurement circuit according to claim 1, characterized in that: The measurement circuit of the lithium battery also includes: A plurality of first filter structures are provided, wherein the first filter structure is electrically connected to first ends of two adjacent thermistors.

4. The lithium battery measurement circuit according to claim 1, characterized in that: The measurement circuit of the lithium battery also includes a three-terminal second switch device and a third switch device, and the detection chip also includes a charging status indication signal output terminal and a discharging status indication signal output terminal. The first end of the second switch device is used to be electrically connected to a load or a power supply, the second end of the second switch device is electrically connected to the first end of the third switch device, the second end of the third switch device is electrically connected to the positive electrode of the lithium battery, the charging status indication signal output terminal is electrically connected to the control end of the second switch device, and the discharging status indication signal output terminal is electrically connected to the control end of the third switch device.

5. The lithium battery measurement circuit according to claim 4, characterized in that: The measurement circuit of the lithium battery also includes a second current limiting device, a third current limiting device, a fourth current limiting device and a second filtering structure. The charging status indication signal output end is electrically connected to the control end of the second switching device through the second current limiting device, and the discharging status indication signal output end is electrically connected to the control end of the third switching device through the third current limiting device. The first end of the second filtering structure is electrically connected to the second end of the second switching device through the fourth current limiting device, and the second end of the second filtering structure is grounded.

6. The lithium battery measurement circuit according to claim 5, characterized in that: The second current limiting device, the third current limiting device and the fourth current limiting device respectively include resistors, and the second filtering structure includes a plurality of capacitors connected in series.

7. The lithium battery measurement circuit according to claim 2, characterized in that: The first current limiting device includes a resistor.

8. The lithium battery measurement circuit according to claim 3, characterized in that: The first filtering structure includes a capacitor.

9. The lithium battery measuring circuit according to any one of claims 1 to 8, characterized in that: The voltage divider device includes a resistor, and the first switch device includes a MOS tube.

10. A lithium battery system, characterized in that: include: A lithium battery, comprising a plurality of battery cells connected in series, wherein the positive electrode of the battery cell at the head of the series connection is the positive electrode of the lithium battery, and the negative electrode of the battery cell at the tail of the series connection is the negative electrode of the lithium battery; A measuring circuit for a lithium battery according to any one of claims 1 to 9.

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