High-precision acquisition circuit for cell shell pressure

Abstract

The invention relates to the technical field of battery management, transmission and the like, and provides a high-precision cell shell pressure acquisition circuit, which comprises N switching circuits and M bypass unit systems, each switch circuit in the N switch circuits is connected with one battery cell, so that a plurality of battery cells are connected in series to form a battery cell series loop; in the M bypass unit systems, a single bypass unit system is connected with a single battery cell in the battery cell series loop, is connected with a single switch circuit in the N switch circuits, and is used for independently monitoring the battery cell shell pressure of the single battery cell and bypassing the monitored single battery cell from the battery cell series loop according to the monitored state of the battery cell shell pressure; therefore, multiple strings of cells form high voltage, the conversion efficiency of the formation and capacity grading system is improved, only one current exists in a series loop, the consistency of the cell formation process is ensured, and the purposes of improving the shell pressure test efficiency of the cells and reducing the test cost are achieved.

Description

Technical Field

[0001] The present invention relates to the technical fields of battery management, transmission, etc., and in particular to a high-precision acquisition circuit for battery cell shell pressure. Background Art

[0002] After the traditional battery cell is divided into different capacities, the shell pressure of the battery cell needs to be tested separately to ensure the insulation between the battery cell shell and the negative electrode. The existing battery cell shell pressure test solution is to design a separate station after the battery cell is divided into different capacities. After the battery cell shell is pressed through the PLC automatic needle bed pressing structure, a multimeter is connected to collect shell pressure data for judgment. This battery cell shell pressure test method adds a station to test the shell pressure during the automated production process, which reduces production efficiency and detects that the abnormal battery cell has gone through all normal processes, thereby increasing production costs.

[0003] In summary, the existing battery cell shell pressure testing technology has technical problems such as low detection efficiency and high detection cost. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies in the prior art to at least a certain extent, and to provide a high-precision acquisition circuit for battery cell shell pressure, so as to improve the efficiency of battery cell shell pressure testing and reduce testing costs.

[0005] The high-precision acquisition circuit of the battery cell shell pressure provided by the present invention comprises: N switch circuits; each of the N switch circuits is connected to a battery cell, so that multiple battery cells are connected in series to form a battery cell series loop; N is a natural number greater than 2; M bypass unit systems; among the M bypass unit systems, a single bypass unit system is connected to a single battery cell in the battery cell series circuit and to a single switch circuit in the N switch circuits, and is used to independently monitor the battery case pressure of the single battery cell, and bypass the monitored single battery cell from the battery cell series circuit according to the state of the monitored battery case pressure; M is a natural number greater than 2.

[0006] Furthermore, the single bypass unit system also independently monitors the battery voltage VB of the single battery cell, compares the monitored battery voltage VB with the preset normal charge and discharge voltage, and when the monitored battery voltage VB reaches the preset normal charge and discharge voltage, the single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit, and determines that the shell pressure of the monitored single battery cell is normal; when the monitored battery voltage VB exceeds the preset normal charge and discharge voltage, the single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit.

[0007] Further, when the single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit according to the monitored state of the battery cell case pressure, it includes: The single bypass unit system compares the monitored battery cell case pressure with the set abnormal voltage judgment value; When the battery cell case pressure reaches the abnormal voltage judgment value, the single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit.

[0008] Furthermore, the battery cell series circuit includes a total series negative terminal BAT- and a total series positive terminal BAT+.

[0009] Furthermore, the high-precision acquisition circuit of the battery cell shell pressure also includes a central computer control system DPU; the central computer control system DPU is communicatively connected with the M bypass unit systems.

[0010] Furthermore, when the single bypass unit system bypasses the single battery cell to be monitored out of the battery cell series circuit, a control switch signal is sent to the single switch circuit connected to the single bypass unit system to control the switch state of the single switch circuit connected to the single bypass unit system, so that the single battery cell to be monitored is bypassed out of the battery cell series circuit.

[0011] Furthermore, the intermediate computer control system DPU is communicatively connected with the single bypass unit system among the M bypass unit systems via an RS485 bus.

[0012] Furthermore, the cell shell pressure is set to VR. When a single bypass unit system independently monitors the cell shell pressure VR of the single cell, it also collects the tab temperature T of the single cell and transmits it to the mid-level computer control system DPU. The mid-level computer control system DPU determines the defective cell based on the tab temperature T.

[0013] Furthermore, the battery cell shell pressure is set to VR. When a single bypass unit system independently monitors the battery cell shell pressure VR of the single battery cell, it also collects the current probe voltage VS at both ends of the single battery cell and transmits it to the mid-level computer control system DPU. The mid-level computer control system DPU determines the defective battery cell based on the current probe voltage VS, and determines the pressing state of the battery cell test fixture based on the current probe voltage VS and the battery voltage VB.

[0014] Furthermore, the cell shell pressure is set to VR. When a single bypass unit system independently monitors the cell shell pressure VR of the single cell, it also collects the battery voltage VB at both ends of the single cell and transmits it to the mid-level computer control system DPU. The mid-level computer control system DPU determines the defective cell based on the battery voltage VB at both ends, and determines the pressing state of the test fixture of the cell based on the battery voltage VB and the current probe voltage VS.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The high-precision acquisition circuit of battery cell shell pressure provided by the present invention comprises N switch circuits and M bypass unit systems; each of the N switch circuits is connected to a battery cell, so as to connect multiple battery cells in series to form a battery cell series circuit; in the M bypass unit systems, a single bypass unit system is connected to a single battery cell in the battery cell series circuit, and is connected to a single switch circuit in the N switch circuits, so as to independently monitor the battery cell shell pressure of the single battery cell, and bypass the monitored single battery cell from the battery cell series circuit according to the state of the monitored battery cell shell pressure, so as to form high voltage with multiple strings of battery cells, improve the conversion efficiency of the capacity conversion system, and have only one current in the series circuit to ensure the consistency of the battery cell formation process, so as to achieve the purpose of improving the battery cell shell pressure test efficiency and reducing the test cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative labor.

[0017] Figure 1 This is a circuit structure diagram of a high-precision acquisition circuit for a battery cell shell pressure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a circuit structure of a single bypass unit system according to an embodiment of the present invention; Figure 3 It is a schematic diagram of a negative electrode to shell resistance circuit of a single battery cell according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar methods or methods having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but are not to be construed as limiting the present invention. All other embodiments obtained by ordinary technicians in the field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0019] See also Figure 1-Figure 3 The high-precision acquisition circuit of the battery cell shell pressure provided by the embodiment of the present invention includes: N switch circuits; each of the N switch circuits is connected to a battery cell, so that multiple battery cells are connected in series to form a battery cell series circuit; N is a natural number greater than 2; wherein the battery cell series circuit includes a series total negative terminal BAT- and a series total positive terminal BAT+. N switch circuits such as switch circuit S1, switch circuit S2, switch circuit S3, etc. Multiple battery cells such as battery cell B1, battery cell B2, battery cell B3, etc.

[0020] M bypass unit systems; among the M bypass unit systems, a single bypass unit system is connected to a single battery cell in the battery cell series circuit and to a single switch circuit in the N switch circuits, and is used to independently monitor the battery case pressure of the single battery cell, and bypass the monitored single battery cell from the battery cell series circuit according to the state of the monitored battery case pressure; M is a natural number greater than 2.

[0021] It should be noted that, in the present embodiment, each of the N switch circuits is connected to a battery cell, so as to connect multiple battery cells in series to form a battery cell series circuit; in the M bypass unit systems, a single bypass unit system is connected to a single battery cell in the battery cell series circuit, and is connected to a single switch circuit in the N switch circuits, for independently monitoring the battery case pressure of the single battery cell, and bypassing the monitored single battery cell from the battery cell series circuit according to the monitored state of the battery cell shell pressure, thereby realizing the formation of high voltage by multiple strings of battery cells and improving the conversion efficiency of the battery cell formation system. There is only one current in the series circuit to ensure the consistency of the battery cell formation process, thereby achieving the purpose of improving the battery cell shell pressure test efficiency and reducing the test cost.

[0022] In some preferred embodiments, the single bypass unit system also independently monitors the battery voltage VB of the single battery cell, compares the monitored battery voltage VB with the preset normal charge and discharge voltage, and when the monitored battery voltage VB reaches the preset normal charge and discharge voltage, the single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit, and determines that the shell pressure of the monitored single battery cell is normal. When the monitored battery voltage VB exceeds the preset normal charge and discharge voltage, the single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit. It should be noted that in this embodiment, setting the normal charge and discharge voltage as the judgment standard can ensure that the battery cell operates in the best working state and avoid overcharging or undercharging. By comparing the battery voltage and the set value, the battery cell state can be accurately judged, thereby deciding whether to bypass, which helps to extend the battery cell life and maintain system stability. By clarifying the bypass conditions, automatic control can be achieved, human intervention can be reduced, and the intelligence level of the system can be improved. It should be noted that, in the present embodiment, when the monitored battery voltage VB reaches the preset normal charge and discharge voltage, not only can the monitored single battery cell be bypassed from the battery cell series circuit, but also the shell pressure of the monitored single battery cell can be determined to be normal, thereby realizing the shell pressure judgment of the single battery cell.

[0023] In some preferred embodiments, when a single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit according to the monitored state of the battery cell shell pressure, it includes: the single bypass unit system compares the monitored battery cell shell pressure with the set abnormal voltage judgment value; when the battery cell shell pressure reaches the abnormal voltage judgment value, the single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit. It should be noted that in this embodiment, setting the abnormal voltage judgment value can identify the abnormal state of the battery cell, prevent the battery cell from over-discharging or overcharging, and help protect the battery cell and extend its service life. When an abnormality occurs in the battery cell, timely bypassing can avoid the failure of a single battery cell causing the failure of the entire battery cell series circuit, ensuring the continuous and stable operation of the system. In addition, abnormal voltage may indicate potential dangers of the battery cell, such as overheating, leakage or explosion risks. Bypassing abnormal batteries in time can improve the overall safety of the system.

[0024] In some preferred embodiments, the high-precision acquisition circuit of the battery cell shell pressure also includes a central computer control system DPU; the central computer control system DPU is communicatively connected to the M bypass unit systems. Further, the central computer control system DPU is communicatively connected to the single bypass unit system in the M bypass unit systems via the RS485 bus. It should be noted that in this embodiment, through the central computer control system DPU, each bypass unit system can be centrally managed and controlled, thereby simplifying the management complexity of the bypass unit system. In addition, the central computer control system DPU can collect and process the data transmitted back from the bypass unit system in real time, conduct comprehensive analysis and judgment, improve the accuracy and real-time performance of data processing, and ensure the accuracy and reliability of battery cell shell pressure monitoring. In addition, the RS485 bus has the advantages of strong anti-interference ability, long communication distance, and many network nodes. The application of the RS485 bus can ensure the stability and reliability of communication between the DPU and the bypass unit system, and reduce errors in the data transmission process. The RS485 bus supports multi-point communication, which facilitates the expansion and upgrade of the system. When the system needs to add a bypass unit system, it can be easily expanded, thereby enhancing the flexibility and adaptability of the system.

[0025] In some preferred embodiments, when the single bypass unit system bypasses the single cell being monitored from the cell series circuit, the single bypass unit system sends a control switch signal to the single switch circuit connected to the single bypass unit system to control the switch state of the single switch circuit connected to the single bypass unit system, so that the single cell being monitored is bypassed from the cell series circuit. It should be noted that in this embodiment, by sending a control switch signal to control the state of the switch circuit, it is possible to achieve precise control of the bypass process, ensure that the cell is bypassed at the right time, avoid misoperation or inappropriate timing during the bypass process, and ensure the stability and reliability of the system. In addition, by controlling the state of the switch circuit to bypass the cell, the interference to other cells and the entire series circuit can be minimized, ensuring that the impact of the bypass operation on the system is minimized, and maintaining the normal working state of other cells. Among them, the control switch signal is RY.

[0026] In some preferred embodiments, the cell shell pressure is set to VR, and when a single bypass unit system independently monitors the cell shell pressure VR of the single cell, it also collects the tab temperature T of the single cell and transmits it to the intermediate control system DPU, and the intermediate control system DPU determines the bad cell based on the tab temperature T. It should be noted that the state of the cell cannot be fully reflected by monitoring the cell shell pressure VR alone, and the tab temperature T is another important parameter that can provide more comprehensive information on the health status of the cell. By monitoring the two parameters, it is possible to more accurately determine whether there is a problem with the cell, thereby improving the comprehensiveness and accuracy of monitoring. An increase in the tab temperature of the cell is usually an early sign of internal problems in the cell (such as internal short circuit, overheating, etc.). Discovering temperature abnormalities in advance can prevent potential faults. By monitoring the tab temperature, cells with possible problems can be discovered and bypassed in a timely manner to prevent the spread of faults and protect the safety of the entire system.

[0027] In some preferred embodiments, the cell shell pressure is set to VR, and when a single bypass unit system independently monitors the cell shell pressure VR of the single cell, it also collects the current probe voltage VS at both ends of the single cell and transmits it to the intermediate control system DPU, and the intermediate control system DPU judges the bad cell according to the current probe voltage VS, and judges the pressing state of the test fixture of the cell according to the current probe voltage VS and the battery voltage VB. It should be noted that the health state of the cell depends not only on the cell shell pressure VR, but also on the current probe voltage VS at both ends. The current probe voltage VS can reflect the current flow and internal resistance of the cell. By combining VR and VS, the health state of the cell can be judged more accurately and the detection accuracy can be improved. Abnormal current probe voltage VS may indicate problems inside the cell, such as internal short circuit or poor electrode contact. These problems may not be fully detected by VR. By monitoring the current probe voltage VS, internal problems of the cell can be discovered earlier, and timely measures can be taken to avoid further damage. In addition, the pressing state of the cell test fixture has an important impact on the accuracy of the test results. If the pressing is not good, the contact resistance may increase, affecting the performance test of the battery cell. By monitoring the current probe voltage VS and the battery voltage VB, the pressing state of the test fixture can be judged to ensure the stability and reliability of the test environment.

[0028] In some preferred embodiments, the cell shell pressure is set to VR. When a single bypass unit system independently monitors the cell shell pressure VR of the single cell, it also collects the battery voltage VB at both ends of the single cell and transmits it to the intermediate control system DPU. The intermediate control system DPU judges the bad cell according to the battery voltage VB at both ends, and judges the pressing state of the test fixture of the cell according to the battery voltage VB and the current probe voltage VS. It should be noted that the cell shell pressure VR alone may not be sufficient to fully reflect the health of the cell. The battery voltage VB provides additional information on the distribution of the battery voltage VB, which helps to more comprehensively evaluate the cell status. Combining VR and VB, it can more accurately determine whether there is a problem with the cell, thereby improving the comprehensiveness and accuracy of the detection. The battery voltage VB can reflect the voltage distribution inside the cell. If the battery voltage VB is abnormal, it may mean that the cell has internal short circuit, poor contact or uneven electrolyte distribution. By monitoring the battery voltage VB, potential problems inside the cell can be discovered early, and timely measures can be taken to prevent the fault from expanding. In addition, the accuracy of the battery voltage VB is affected by the pressing state of the test fixture. If the clamp is not pressed properly, the contact resistance will increase, affecting the accuracy of voltage measurement. The clamp pressing state can be judged by the battery voltage VB and the current probe voltage VS to ensure the stability and reliability of the battery cell test environment.

[0029] In some further preferred embodiments, a single bypass unit system includes a VB voltage acquisition module, a VS voltage acquisition module, a VR voltage acquisition module, a VT temperature acquisition module, a resistor R1, a fuse F1, a temperature probe, an ADC chip and an MCU; the acquisition end of the VB voltage acquisition module is respectively connected to the positive pole and the negative pole of the pole ear of the single battery cell, and the output end is connected to the ADC chip; the acquisition end of the VS voltage acquisition module is respectively connected to the positive pole and the negative pole of the pole ear of the single battery cell, and the output end is connected to the ADC chip; the temperature probe is connected to the positive pole of the pole ear of the single battery cell and then connected in series with the fuse F1 and the resistor R1, the acquisition end of the VR voltage acquisition module is connected to both ends of the resistor R1, and the output end of the VR voltage acquisition module is connected to the ADC chip; the acquisition end of the VT temperature acquisition module is connected to the temperature probe, the output end of the VT temperature acquisition module is connected to the ADC chip, the ADC chip is connected to the MCU, the MCU is connected to the intermediate computer control system DPU, and the intermediate computer control system DPU is Figure 2The DPU mid-position machine module; the VR voltage acquisition module is integrated with the temperature probe, and the fuse F1 is connected to the outer shell of the temperature probe. The temperature probe is pressed so that the probe head is in contact with the outer shell of the single battery cell. The head of the temperature probe (also called a temperature needle) is pointed to ensure good contact. Assume that the negative electrode to shell resistance of the single battery cell is RS, and the negative electrode to shell resistance RS is connected to the negative electrode of the single battery cell, and then connected in series with resistor R1 and fuse F1, and then connected to the positive electrode of the single battery cell; the voltage across the resistor R1 is V1, RS = (VB*R1 / V1)-R1.

[0030] It should be noted that the VB voltage acquisition module is used to collect the battery voltage VB at both ends of the single battery cell and transmit it to the ADC chip, the VS voltage acquisition module is used to collect the current probe voltage VS of the single battery cell and transmit it to the ADC chip, and the VT temperature acquisition module is used to collect the tab temperature T of the single battery cell and transmit it to the ADC chip. The ADC chip performs ADC processing on the battery voltage VB, the current probe voltage VS and the tab temperature T, and outputs them to the MCU, which then transmits them to the intermediate computer control system DPU through the MCU to judge the defective battery cell and the pressing state of the battery cell test fixture.

[0031] It should also be noted that the VR voltage acquisition module monitors the cell shell pressure VR of the single cell and transmits it to the ADC chip. The ADC chip performs ADC processing on the cell shell pressure VR and transmits it to the MCU. The MCU bypasses the monitored single cell from the cell series circuit according to the state of the monitored cell shell pressure.

[0032] It should be noted that in this embodiment, the VR voltage acquisition module and the temperature probe are integrated into one mode to improve space utilization. During the charging process after the battery cell is formed, the negative electrode and shell pressure are detected in real time. If an abnormality is found, an alarm can be immediately issued to stop the subsequent process of the battery cell, thereby achieving the advantages of saving efficiency and cost.

[0033] The above is a description of the technical solution provided by the present invention. For those skilled in the art, according to the ideas of the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A high-precision acquisition circuit for battery cell shell pressure, characterized in that: include: N switch circuits; each of the N switch circuits is connected to a battery cell, so that multiple battery cells are connected in series to form a battery cell series loop; N is a natural number greater than 2; M bypass unit systems; among the M bypass unit systems, a single bypass unit system is connected to a single battery cell in the battery cell series circuit and to a single switch circuit in the N switch circuits, and is used to independently monitor the battery case pressure of the single battery cell, and bypass the monitored single battery cell from the battery cell series circuit according to the state of the monitored battery case pressure; M is a natural number greater than 2.

2. The high-precision acquisition circuit of the battery cell shell pressure as claimed in claim 1, characterized in that: The single bypass unit system also independently monitors the battery voltage VB of the single battery cell, and compares the monitored battery voltage VB with the preset normal charge and discharge voltage. When the monitored battery voltage VB reaches the preset normal charge and discharge voltage, the single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit, and determines that the shell pressure of the monitored single battery cell is normal. When the monitored battery voltage VB exceeds the preset normal charge and discharge voltage, the single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit.

3. The high-precision acquisition circuit of the battery cell shell pressure as claimed in claim 1, characterized in that: When a single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit according to the monitored state of the battery cell shell pressure, it includes: The single bypass unit system compares the monitored battery cell case pressure with the set abnormal voltage judgment value; When the battery cell case pressure reaches the abnormal voltage judgment value, the single bypass unit system bypasses the monitored single battery cell from the battery cell series circuit.

4. The high-precision acquisition circuit of the battery cell shell pressure as claimed in claim 1, characterized in that: The battery cell series circuit includes a total series negative terminal BAT- and a total series positive terminal BAT+.

5. The high-precision acquisition circuit of the battery cell shell pressure as claimed in claim 2, characterized in that: It also includes a mid-level machine control system DPU; the mid-level machine control system DPU is communicatively connected with the M bypass unit systems.

6. The high-precision acquisition circuit for battery cell shell pressure according to any one of claims 1 to 4, characterized in that: When the single bypass unit system bypasses the single battery cell to be monitored out of the battery cell series circuit, a control switch signal is sent to the single switch circuit connected to the single bypass unit system to control the switch state of the single switch circuit connected to the single bypass unit system, so that the single battery cell to be monitored is bypassed out of the battery cell series circuit.

7. The high-precision acquisition circuit of the battery cell shell pressure as claimed in claim 5, characterized in that: The intermediate computer control system DPU is communicatively connected with the single bypass unit system among the M bypass unit systems via an RS485 bus.

8. The high-precision acquisition circuit of the battery cell shell pressure as claimed in claim 5, characterized in that: The cell shell pressure is set to VR. When a single bypass unit system independently monitors the cell shell pressure VR of the single cell, it also collects the tab temperature T of the single cell and transmits it to the mid-level computer control system DPU. The mid-level computer control system DPU determines a defective cell based on the tab temperature T.

9. The high-precision acquisition circuit of the battery cell shell pressure as claimed in claim 5, characterized in that: The cell shell pressure is set to VR. When a single bypass unit system independently monitors the cell shell pressure VR of the single cell, it also collects the current probe voltage VS at both ends of the single cell and transmits it to the mid-level computer control system DPU. The mid-level computer control system DPU determines a defective cell based on the current probe voltage VS, and determines the pressing state of the test fixture of the cell based on the current probe voltage VS and the battery voltage VB.

10. The high-precision acquisition circuit of battery cell shell pressure according to claim 9, characterized in that: The cell shell pressure is set to VR. When a single bypass unit system independently monitors the cell shell pressure VR of the single cell, it also collects the battery voltage VB at both ends of the single cell and transmits it to the mid-level computer control system DPU. The mid-level computer control system DPU determines the defective cell based on the battery voltage VB at both ends, and determines the pressing state of the test fixture of the cell based on the battery voltage VB and the current probe voltage VS.

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