Cascade charging and discharging system and method for lithium battery module testing

Abstract

The invention discloses an echelon charging and discharging system and method for lithium battery module testing, and belongs to the field of lithium battery testing, the echelon charging and discharging system comprises a testing power supply, a battery pack complete machine, a second-stage charging system, a second-stage battery module, a third-stage charging system and a third-stage battery module, the battery pack complete machine comprises a plurality of first-stage battery modules, each of the first-stage battery module, the second-stage battery module and the third-stage battery module comprises a plurality of single batteries, the number of the single batteries in the first-stage battery module is greater than that of the single batteries in the second-stage battery module, and the number of the single batteries in the second-stage battery module is greater than that of the single batteries in the third-stage battery module; the input end of the test power supply is connected with the mains supply, the output end of the test power supply is connected with the battery pack complete machine, the battery pack complete machine is connected with the secondary battery module through the secondary charging system, and the secondary battery module is connected with the tertiary battery module through the tertiary battery module, so that energy can be saved, and the cost can be reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery testing, and particularly relates to a stepped charge and discharge system and method for lithium battery module testing. Background Art

[0002] In order to test the performance of a lithium battery module such as power utilization rate, charge and discharge efficiency, cycle life, etc., it is usually necessary to perform multiple charging and discharging operations on the lithium battery module. By detecting data such as the time taken for the charging and discharging processes and the magnitude of current and voltage, the power utilization rate, charge and discharge efficiency, cycle life, etc. of the lithium battery module can be tested.

[0003] Currently, common charge and discharge systems include a test power supply, a lithium battery module, and a battery charge and discharge tester. With this structure, the test power supply is used to charge the lithium battery module. After the lithium battery module is fully charged, the lithium battery module is connected to a load for discharging, thereby realizing the charge and discharge operation of the lithium battery module. By using the battery charge and discharge tester to detect data such as the time taken for the charge and discharge process of the lithium battery module and the magnitude of current and voltage, the power utilization rate, charge and discharge efficiency, cycle life, etc. of the lithium battery module can be tested. However, when using the above charge and discharge system, each lithium battery module needs to be charged once through the test power supply during testing, and the fully charged lithium battery module needs to discharge the electrical energy in it for discharge detection, resulting in waste of electrical energy and increased testing costs. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a stepped charge and discharge system and method for lithium battery module testing. The technical problems to be solved by the present invention are realized through the following technical solutions:

[0005] In a first aspect, the present invention provides a stepped charge and discharge system for lithium battery module testing, including a test power supply, a battery pack unit, a secondary charging system, a secondary battery module, a tertiary charging system, and a tertiary battery module. The battery pack unit includes a plurality of primary battery modules. The primary battery module, the secondary battery module, and the tertiary battery module each include a plurality of battery cells, and the number of battery cells in the primary battery module is greater than the number of battery cells in the secondary battery module, and the number of battery cells in the secondary battery module is greater than the number of battery cells in the tertiary battery module;

[0006] The input end of the test power supply is connected to the mains power, the output end of the test power supply is connected to the battery pack unit, the battery pack unit is connected to the secondary battery module through the secondary charging system, and the secondary battery module is connected to the tertiary battery module through the tertiary battery module.

[0007] In an embodiment of the present invention, the secondary charging system includes an acquisition circuit and a main control circuit. The acquisition circuit includes an input acquisition circuit and an output acquisition circuit;

[0008] The input acquisition circuit is connected between the main control circuit and the entire battery pack, and the output acquisition circuit is connected between the main control circuit and the secondary battery module. The main control circuit is used to be connected to the host computer;

[0009] The input acquisition circuit is used to collect the first current and voltage data output by the entire battery pack and transmit it to the main control circuit. The output acquisition circuit is used to collect the second current and voltage data of the secondary battery module and transmit it to the main control circuit. The main control circuit is used to control the entire battery pack to charge or stop charging the secondary battery module according to the first current and voltage data and the second current and voltage data.

[0010] In an embodiment of the present invention, the input acquisition circuit includes a first resistor, a second resistor, and a third resistor. The main control circuit includes a chip and a DC-DC parallel buck-boost topology circuit;

[0011] One end of the first resistor is electrically connected to the positive electrode of the entire battery pack, and the other end is electrically connected to the DC-DC parallel buck-boost topology circuit;

[0012] One end of the second resistor is connected between the first resistor and the entire battery pack, and the other end is electrically connected to the first end of the third resistor. The second end of the third resistor is grounded;

[0013] The chip includes an ISN1 pin, an ISP1 pin, and a VSENSE1 pin. The ISN1 pin is connected between the first resistor and the DC-DC parallel buck-boost topology circuit. The ISP1 pin is connected between the first resistor and the second resistor. The VSENSE1 pin is connected between the second resistor and the third resistor.

[0014] In an embodiment of the present invention, the output acquisition circuit includes a fourth resistor, a fifth resistor, and a sixth resistor;

[0015] One end of the fourth resistor is electrically connected to the positive electrode of the secondary battery module, and the other end is electrically connected to the DC-DC parallel buck-boost topology circuit;

[0016] One end of the fifth resistor is connected between the fourth resistor and the secondary battery module, and the other end is electrically connected to the first end of the sixth resistor. The second end of the sixth resistor is grounded;

[0017] The chip includes an ISN2 pin, an ISP2 pin, and a VSENSE2 pin. The ISN2 pin is connected between the fourth resistor and the DC-DC parallel buck-boost topology circuit. The ISP2 pin is connected between the fourth resistor and the fifth resistor. The VSENSE2 pin is connected between the fifth resistor and the sixth resistor.

[0018] In one embodiment of the present invention, the DC-DC parallel buck-boost topology circuit includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first switching triode, a second switching triode, a first diode, a second diode, and an inductor. The chip further includes a PWM1 pin and a PWM2 pin;

[0019] The first end of the first capacitor is connected to the first resistor, and the second end is connected to the negative electrode of the battery pack whole machine. The first end of the fourth capacitor is connected to the fourth resistor, and the second end is connected to the negative electrode of the secondary battery module;

[0020] The second capacitor and the third capacitor are connected in series and then connected in parallel across both ends of the first capacitor. A ground wire is connected between the second capacitor and the third capacitor. The fifth capacitor and the sixth capacitor are connected in series and then connected in parallel across both ends of the fourth capacitor. A ground wire is connected between the fifth capacitor and the sixth capacitor;

[0021] The first switching triode and the first diode are connected in series and then connected in parallel across both ends of the first capacitor. The emitter of the first switching triode is connected to the negative electrode of the first diode, the collector is connected to the first end of the first capacitor, the base is connected to the PWM1 pin, and the positive electrode of the first diode is connected to the second end of the first capacitor;

[0022] The second switching triode and the second diode are connected in series and then connected in parallel across both ends of the fourth capacitor. The emitter of the second switching triode is connected to the negative electrode of the second diode, the collector is connected to the first end of the fourth capacitor, the base is connected to the PWM2 pin, and the positive electrode of the second diode is connected to the second end of the fourth capacitor;

[0023] One end of the inductor is connected between the first switching triode and the first diode, and the other end is connected between the second switching triode and the second diode.

[0024] In one embodiment of the present invention, it further includes a first fuse and a second fuse. The first fuse is arranged between the positive electrode of the battery pack whole machine and the input acquisition circuit, and the second fuse is arranged between the positive electrode of the secondary battery module and the output acquisition circuit.

[0025] In one embodiment of the present invention, the circuit structure of the three-stage charging system is the same as that of the two-stage charging system.

[0026] In a second aspect, the present invention further provides a stepwise charge and discharge method for testing a lithium battery module, which is applied to the stepwise charge and discharge system for testing a lithium battery module provided in the above solution. The stepwise charge and discharge system includes a test power supply, a battery pack whole machine, a two-stage charging system, a secondary battery module, a three-stage charging system, and a three-stage battery module. The method includes:

[0027] Charging the battery pack whole machine through the test power supply;

[0028] After the entire battery pack is fully charged, charge the secondary battery module through the entire battery pack and the secondary charging system;

[0029] Charge the tertiary battery module through the secondary battery module and the tertiary charging system;

[0030] Control the discharge of the tertiary battery module.

[0031] In an embodiment of the present invention, the secondary charging system includes an acquisition circuit and a main control circuit. The acquisition circuit includes an input acquisition circuit and an output acquisition circuit. The main control circuit includes a chip and a DC-DC parallel buck-boost topology circuit;

[0032] Charging the secondary battery module through the entire battery pack and the secondary charging system specifically includes:

[0033] Collect the first current and voltage data output by the entire battery pack through the input acquisition circuit, and transmit the first current and voltage data to the main control circuit;

[0034] Collect the second current and voltage data of the secondary battery module through the output acquisition circuit, and transmit the second current and voltage data to the main control circuit;

[0035] According to the first current and voltage data and the second current and voltage data, generate a driving signal through the chip, and transmit the driving signal to the DC-DC parallel buck-boost topology circuit. The driving signal includes a boost signal and a buck signal;

[0036] According to the driving signal, adjust the charging voltage of the secondary battery module through the DC-DC parallel buck-boost topology circuit.

[0037] In an embodiment of the present invention, generating a driving signal through the chip according to the first current and voltage data and the second current and voltage data specifically includes:

[0038] When the voltage of the entire battery pack is greater than the voltage of the secondary battery module, generate a buck signal through the chip;

[0039] When the voltage of the entire battery pack is less than the voltage of the secondary battery module, generate a boost signal through the chip;

[0040] Adjusting the charging voltage of the secondary battery module through the DC-DC parallel buck-boost topology circuit according to the driving signal specifically includes:

[0041] When the driving signal is a boost signal, perform boosting through the DC-DC parallel buck-boost topology circuit. At this time, the secondary charging system charges the secondary battery module;

[0042] When the driving signal is a buck signal, bucking is performed through the DC-DC parallel buck-boost topology circuit. At this time, the secondary charging system stops charging the secondary battery module.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] In the above solution of the present application, the cascade charge and discharge system includes a test power supply, a battery pack whole machine, a secondary charging system, a secondary battery module, a tertiary charging system, and a tertiary battery module. The battery pack whole machine includes a plurality of primary battery modules. The primary battery module, the secondary battery module, and the tertiary battery module all include a plurality of battery cells. Moreover, the number of battery cells in the primary battery module is greater than the number of battery cells in the secondary battery module, and the number of battery cells in the secondary battery module is greater than the number of battery cells in the tertiary battery module. The input end of the test power supply is connected to the commercial power, the output end of the test power supply is connected to the battery pack whole machine, the battery pack whole machine is connected to the secondary battery module through the secondary charging system, and the secondary battery module is connected to the tertiary battery module through the tertiary battery module. With this structure, when charging the battery pack whole machine through the test power supply, the charging operation of the battery pack whole machine can be realized. When charging the secondary battery module through the battery pack whole machine, not only the charging operation of the secondary battery module can be realized, but also the discharging operation of the battery pack whole machine can be realized. When charging through the secondary battery module, not only the charging operation of the tertiary battery module can be realized, but also the discharging operation of the secondary battery module can be realized. In this way, using the electric energy in the previous battery module to charge the next battery module can not only realize the charging of the next battery module, but also realize the discharging of the previous battery module. Through the above charge and discharge system of the present application, cascade charging and discharging can be realized. Therefore, when testing multiple lithium battery modules, only the first battery pack whole machine needs to be charged through the test power supply, thus saving the charging cost of the test power supply and further saving the test cost. And, the fully charged lithium battery module can charge the next battery module, thus making use of the electric energy in the battery module, improving the power utilization rate of the test power supply, and avoiding waste of electric energy.

[0045] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0046] Figure 1 is a schematic diagram of the cascade charge and discharge system provided by an embodiment of the present invention;

[0047] Figure 2 is a schematic diagram of the battery pack whole machine, the secondary charging system, and the secondary battery module in an embodiment of the present invention;

[0048] Figure 3It is the circuit diagram of the battery pack whole machine, the secondary charging system and the secondary battery module in the embodiment of the present invention;

[0049] Figure 4 It is the schematic diagram of the secondary battery module, the secondary charging system and the tertiary battery module in the embodiment of the present invention. Specific embodiments

[0050] The following further describes the present invention in detail with specific embodiments, but the implementation manners of the present invention are not limited thereto.

[0051] Embodiment 1:

[0052] Please refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 In the embodiment of the present invention, a cascade charge and discharge system for lithium battery module testing is provided, including a test power supply, a battery pack whole machine, a secondary charging system, a secondary battery module, a tertiary charging system and a tertiary battery module. The battery pack whole machine includes a plurality of primary battery modules. The primary battery module, the secondary battery module and the tertiary battery module all include a plurality of battery cells, and the number of battery cells in the primary battery module is greater than the number of battery cells in the secondary battery module, and the number of battery cells in the secondary battery module is greater than the number of battery cells in the tertiary battery module. The input end of the test power supply is connected to the mains, the output end of the test power supply is connected to the battery pack whole machine, the battery pack whole machine and the secondary battery module are connected through the secondary charging system, and the secondary battery module and the tertiary battery module are connected through the tertiary battery module.

[0053] In some embodiments of the present application, the input end of the test power supply can be connected to the 380V mains.

[0054] In some embodiments of the present application, the plurality of primary battery modules in the battery pack whole machine can be connected in series or in parallel.

[0055] In some embodiments of the present application, the secondary charging system is a charging system that controls the battery pack whole machine to charge the secondary battery module.

[0056] In some embodiments of the present application, the tertiary charging system is a charging system that controls the secondary battery module to charge the tertiary battery module.

[0057] In the above solution of the present application, the cascade charge and discharge system includes a test power supply, a battery pack as a whole, a secondary charging system, a secondary battery module, a tertiary charging system, and a tertiary battery module. The battery pack as a whole includes a plurality of primary battery modules. The primary battery module, the secondary battery module, and the tertiary battery module all include a plurality of battery cells. Moreover, the number of battery cells in the primary battery module is greater than the number of battery cells in the secondary battery module, and the number of battery cells in the secondary battery module is greater than the number of battery cells in the tertiary battery module. The input end of the test power supply is connected to the mains power, and the output end of the test power supply is connected to the battery pack as a whole. The battery pack as a whole and the secondary battery module are connected through the secondary charging system, and the secondary battery module and the tertiary battery module are connected through the tertiary charging system. With this structure, when the battery pack as a whole is charged by the test power supply, the charging operation of the battery pack as a whole can be realized. When the secondary battery module is charged by the battery pack as a whole, not only the charging operation of the secondary battery module can be realized, but also the discharging operation of the battery pack as a whole can be realized. When the tertiary battery module is charged by the secondary battery module, not only the charging operation of the tertiary battery module can be realized, but also the discharging operation of the secondary battery module can be realized. Thus, the electric energy in the previous battery module is used to charge the next battery module, which can not only realize the charging of the next battery module, but also realize the discharging of the previous battery module. Through the above charge and discharge system of the present application, cascade charging and discharging can be realized. Therefore, when multiple lithium battery modules are tested, only the test power supply needs to be used to charge the first battery pack as a whole, thereby saving the charging cost of the test power supply and further saving the test cost. Moreover, the fully charged lithium battery module can charge the next battery module, thereby making use of the electric energy in the battery module, improving the power utilization rate of the test power supply, and avoiding waste of electric energy.

[0058] In some embodiments of the present application, such as Figure 1 、 Figure 2 and Figure 3As shown in the figure, the secondary charging system includes a collection circuit and a main control circuit. The collection circuit includes an input collection circuit and an output collection circuit. The input collection circuit is connected between the main control circuit and the entire battery pack, and the output collection circuit is connected between the main control circuit and the secondary battery module. The main control circuit is used to connect to the host computer. The input collection circuit is used to collect the first current and voltage data output by the entire battery pack and transmit it to the main control circuit. The output collection circuit is used to collect the second current and voltage data of the secondary battery module and transmit it to the main control circuit. The main control circuit is used to control the entire battery pack to charge or stop charging the secondary battery module according to the first current and voltage data and the second current and voltage data. With this structure, the first current and voltage data output by the entire battery pack is collected through the input collection circuit, the second current and voltage data of the secondary battery module is collected through the output collection circuit, and the main control circuit controls the entire battery pack to charge or stop charging the secondary battery module according to the first current and voltage data and the second current and voltage data, enabling the secondary battery module to perform a charging operation and the entire battery pack to perform a discharging operation.

[0059] In some embodiments of the present application, as Figure 2 and Figure 3 shown, the input collection circuit includes a first resistor, a second resistor, and a third resistor. The main control circuit includes a chip and a DC-DC parallel buck-boost topology circuit. One end of the first resistor is electrically connected to the positive electrode of the entire battery pack, and the other end is electrically connected to the DC-DC parallel buck-boost topology circuit. One end of the second resistor is connected between the first resistor and the entire battery pack, and the other end is electrically connected to the first end of the third resistor. The second end of the third resistor is grounded. The chip includes an ISN1 pin, an ISP1 pin, and a VSENSE1 pin. The ISN1 pin is connected between the first resistor and the DC-DC parallel buck-boost topology circuit. The ISP1 pin is connected between the first resistor and the second resistor. The VSENSE1 pin is connected between the second resistor and the third resistor. With this structure, the first current and voltage data output by the entire battery pack can be collected through the cooperation of the first resistor, the second resistor, and the third resistor and transmitted to the chip. The chip can transmit the first current and voltage data to the host computer. The host computer sends a corresponding instruction to the chip, and the chip sends a drive signal to the DC-DC parallel buck-boost topology circuit, enabling the DC-DC parallel buck-boost topology circuit to control the rise and fall of the voltage to match the charging voltage of the secondary rechargeable battery module.

[0060] In some embodiments of the present application, the DC-DC parallel buck-boost topology circuit is a power electronic circuit module mainly used to achieve flexible conversion of DC voltage, including boost (Boost), buck (Buck), and buck-boost (Buck-Boost) functions.

[0061] In some embodiments of the present application, the chip can be a 16-bit AD sampling chip, which, combined with an optimized software sampling algorithm, can achieve an output current accuracy of 0.1% FS.

[0062] In some embodiments of the present application, the ISN (Current Sense Negative) pin is used for the negative input of the current detection circuit and is usually connected to the low-potential end of the current sampling resistor.

[0063] In some embodiments of the present application, the ISP (Current Sense Positive) pin is used for the positive input of the current detection circuit and is usually connected to the high-potential end of the current sampling resistor. The ISN1 pin and the ISP1 pin are used in combination to measure the current value.

[0064] In some embodiments of the present application, the VSENSE (Voltage Sense) pin is used for the input of the voltage detection circuit to measure the external voltage value.

[0065] In some embodiments of the present application, as Figure 3 shown, the output acquisition circuit includes a fourth resistor, a fifth resistor, and a sixth resistor; one end of the fourth resistor is electrically connected to the positive electrode of the secondary battery module, and the other end is electrically connected to the DC-DC parallel buck-boost topology circuit; one end of the fifth resistor is connected between the fourth resistor and the secondary battery module, and the other end is electrically connected to the first end of the sixth resistor, and the second end of the sixth resistor is grounded; the chip includes an ISN2 pin, an ISP2 pin, and a VSENSE2 pin. The ISN2 pin is connected between the fourth resistor and the DC-DC parallel buck-boost topology circuit, the ISP2 pin is connected between the fourth resistor and the fifth resistor, and the VSENSE2 pin is connected between the fifth resistor and the sixth resistor. With this structure, the second current and voltage data output by the secondary battery module can be acquired through the cooperation of the fourth resistor, the fifth resistor, and the sixth resistor and transmitted to the chip. The chip can transmit the second current and voltage data to the host computer. The host computer sends a corresponding instruction to the chip, and the chip sends a driving signal to the DC-DC parallel buck-boost topology circuit, so that the DC-DC parallel buck-boost topology circuit can control the voltage rise and fall to match the charging voltage of the secondary rechargeable battery module.

[0066] In some embodiments of the present application, as Figure 3As shown in the figure, the DC-DC parallel buck-boost topology circuit includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first switching triode, a second switching triode, a first diode, a second diode, and an inductor. The chip also includes a PWM1 pin and a PWM2 pin; the first end of the first capacitor is connected to the first resistor, and the second end is connected to the negative electrode of the battery pack as a whole. The first end of the fourth capacitor is connected to the fourth resistor, and the second end is connected to the negative electrode of the secondary battery module; the second capacitor and the third capacitor are connected in series and then connected in parallel across both ends of the first capacitor. A ground wire is connected between the second capacitor and the third capacitor. The fifth capacitor and the sixth capacitor are connected in series and then connected in parallel across both ends of the fourth capacitor. A ground wire is connected between the fifth capacitor and the sixth capacitor; the first switching triode and the first diode are connected in series and then connected in parallel across both ends of the first capacitor. The emitter of the first switching triode is connected to the negative electrode of the first diode, the collector is connected to the first end of the first capacitor, the base is connected to the PWM1 pin, and the positive electrode of the first diode is connected to the second end of the first capacitor; the second switching triode and the second diode are connected in series and then connected in parallel across both ends of the fourth capacitor. The emitter of the second switching triode is connected to the negative electrode of the second diode, the collector is connected to the first end of the fourth capacitor, the base is connected to the PWM2 pin, and the positive electrode of the second diode is connected to the second end of the fourth capacitor; one end of the inductor is connected between the first switching triode and the first diode, and the other end is connected between the second switching triode and the second diode. With this structure, the DC-DC parallel buck-boost topology circuit can achieve step-up and step-down, and then match the charging voltage of the secondary battery module.

[0067] In some embodiments of the present application, the PWM (Pulse Width Modulation) pin is used to generate a PWM signal to control the switching state of external power devices (such as MOSFETs, IGBTs). By adjusting the duty cycle of the PWM signal, the magnitude of the output voltage or current can be controlled.

[0068] In some embodiments of the present application, as Figure 3 shown, the cascade charge and discharge system further includes a first fuse and a second fuse. The first fuse is arranged between the positive electrode of the battery pack as a whole and the input acquisition circuit, and the second fuse is arranged between the positive electrode of the secondary battery module and the output acquisition circuit. With this structure, protection is provided by the first fuse and the second fuse, which can improve the safety of the cascade charge and discharge system.

[0069] In some embodiments of the present application, as Figure 4As shown, the circuit structure of the three - level charging system is the same as that of the two - level charging system. With this structure, the circuit structure of the three - level charging system can control the two - level battery module to charge or stop charging the three - level battery module according to the current and voltage output by the two - level battery module, enabling the three - level battery module to perform the charging operation and the two - level battery module to perform the discharging operation.

[0070] In some embodiments of the present application, the three - level charging system includes an acquisition circuit and a main control circuit. The acquisition circuit includes an input acquisition circuit and an output acquisition circuit; the input acquisition circuit is connected between the two - level battery module and the three - level battery module, and the output acquisition circuit is connected between the main control circuit and the three - level battery module. The main control circuit is used to connect to the host computer; the input acquisition circuit is used to acquire the first current - voltage data output by the two - level battery module and transmit it to the main control circuit, and the output acquisition circuit is used to acquire the second current - voltage data of the three - level battery module and transmit it to the main control circuit. The main control circuit is used to control the two - level battery module to charge or stop charging the three - level battery module according to the first current - voltage data and the second current - voltage data.

[0071] In some embodiments of the present application, the input acquisition circuit of the three - level charging system includes a first resistor, a second resistor, and a third resistor. The main control circuit includes a chip and a DC - DC parallel buck - boost topology circuit; one end of the first resistor is electrically connected to the positive electrode of the two - level battery module, and the other end is electrically connected to the DC - DC parallel buck - boost topology circuit; one end of the second resistor is connected between the first resistor and the two - level battery module, and the other end is electrically connected to the first end of the third resistor. The second end of the third resistor is grounded; the chip includes an ISN1 pin, an ISP1 pin, and a VSENSE1 pin. The ISN1 pin is connected between the first resistor and the DC - DC parallel buck - boost topology circuit, the ISP1 pin is connected between the first resistor and the second resistor, and the VSENSE1 pin is connected between the second resistor and the third resistor.

[0072] In some embodiments of the present application, the output acquisition circuit of the three - level charging system includes a fourth resistor, a fifth resistor, and a sixth resistor; one end of the fourth resistor is electrically connected to the positive electrode of the three - level battery module, and the other end is electrically connected to the DC - DC parallel buck - boost topology circuit; one end of the fifth resistor is connected between the fourth resistor and the three - level battery module, and the other end is electrically connected to the first end of the sixth resistor. The second end of the sixth resistor is grounded; the chip includes an ISN2 pin, an ISP2 pin, and a VSENSE2 pin. The ISN2 pin is connected between the fourth resistor and the DC - DC parallel buck - boost topology circuit, the ISP2 pin is connected between the fourth resistor and the fifth resistor, and the VSENSE2 pin is connected between the fifth resistor and the sixth resistor.

[0073] In some embodiments of the present application, the DC-DC parallel buck-boost topology circuit of the three-stage charging system includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first switching triode, a second switching triode, a first diode, a second diode, and an inductor. The chip further includes a PWM1 pin and a PWM2 pin; the first end of the first capacitor is connected to a first resistor, and the second end is connected to the negative electrode of the secondary battery module. The first end of the fourth capacitor is connected to a fourth resistor, and the second end is connected to the negative electrode of the tertiary battery module; the second capacitor and the third capacitor are connected in series and then connected in parallel across both ends of the first capacitor. A ground wire is connected between the second capacitor and the third capacitor. The fifth capacitor and the sixth capacitor are connected in series and then connected in parallel across both ends of the fourth capacitor. A ground wire is connected between the fifth capacitor and the sixth capacitor; the first switching triode and the first diode are connected in series and then connected in parallel across both ends of the first capacitor. The emitter of the first switching triode is connected to the negative electrode of the first diode, the collector is connected to the first end of the first capacitor, the base is connected to the PWM1 pin, and the positive electrode of the first diode is connected to the second end of the first capacitor; the second switching triode and the second diode are connected in series and then connected in parallel across both ends of the fourth capacitor. The emitter of the second switching triode is connected to the negative electrode of the second diode, the collector is connected to the first end of the fourth capacitor, the base is connected to the PWM2 pin, and the positive electrode of the second diode is connected to the second end of the fourth capacitor; one end of the inductor is connected between the first switching triode and the first diode, and the other end is connected between the second switching triode and the second diode.

[0074] Embodiment 2:

[0075] The present invention also provides a stepped charge and discharge method for testing a lithium battery module, which is applied to the stepped charge and discharge system for testing a lithium battery module provided in Embodiment 1 above. The stepped charge and discharge system includes a test power supply, a battery pack as a whole, a secondary charging system, a secondary battery module, a tertiary charging system, and a tertiary battery module. The method includes:

[0076] Charging the battery pack as a whole through the test power supply;

[0077] After the battery pack as a whole is fully charged, charging the secondary battery module through the battery pack as a whole and the secondary charging system;

[0078] Charging the tertiary battery module through the secondary battery module and the tertiary charging system;

[0079] Controlling the discharge of the tertiary battery module.

[0080] For the beneficial effects of Embodiment 2 of the present invention and its various implementation manners, reference can be made to the analysis of the beneficial effects in Embodiment 1 and its various implementation manners, which will not be elaborated here.

[0081] In some embodiments of the present application, the secondary charging system includes a collection circuit and a main control circuit. The collection circuit includes an input collection circuit and an output collection circuit. The main control circuit includes a chip and a DC-DC parallel buck-boost topology circuit;

[0082] Charging the secondary battery module through the battery pack whole machine and the secondary charging system specifically includes:

[0083] Collecting the first current and voltage data output by the battery pack whole machine through the input collection circuit and transmitting the first current and voltage data to the main control circuit;

[0084] Collecting the second current and voltage data of the secondary battery module through the output collection circuit and transmitting the second current and voltage data to the main control circuit;

[0085] Generating a driving signal through the chip according to the first current and voltage data and the second current and voltage data, and transmitting the driving signal to the DC-DC parallel buck-boost topology circuit. The driving signal includes a boost signal and a buck signal;

[0086] Adjusting the charging voltage of the secondary battery module through the DC-DC parallel buck-boost topology circuit according to the driving signal. By adopting this method, the charging voltage of the secondary battery module can be adjusted.

[0087] In some embodiments of the present application, generating a driving signal through the chip according to the first current and voltage data and the second current and voltage data specifically includes:

[0088] When the voltage of the battery pack whole machine is greater than the voltage of the secondary battery module, generating a buck signal through the chip;

[0089] When the voltage of the battery pack whole machine is less than the voltage of the secondary battery module, generating a boost signal through the chip;

[0090] Adjusting the charging voltage of the secondary battery module through the DC-DC parallel buck-boost topology circuit according to the driving signal specifically includes:

[0091] When the driving signal is a boost signal, boosting through the DC-DC parallel buck-boost topology circuit. At this time, the secondary charging system charges the secondary battery module;

[0092] When the driving signal is a buck signal, bucking through the DC-DC parallel buck-boost topology circuit. At this time, the secondary charging system stops charging the secondary battery module. By adopting this method, the charging voltage of the secondary battery module can be accurately adjusted.

[0093] In the description of the present invention, it should be understood that the terms "first", "second", "third", "fourth", "fifth", and "sixth" are used for descriptive purposes only, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", "third", "fourth", "fifth", or "sixth" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0094] Although the present application has been described in conjunction with various embodiments herein, however, in practicing the claimed present application, those skilled in the art can understand and realize other variations of the disclosed embodiments by viewing the accompanying drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "one" does not exclude a plurality. A single processor or other unit may implement several functions recited in the claims. Certain measures are recited in mutually different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0095] Those skilled in the art should understand that the embodiments of the present application may be provided as a method, an apparatus (device), or a computer program product. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects, which are collectively referred to herein as "modules" or "systems". Moreover, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The computer program is stored / distributed in a suitable medium, provided together with other hardware or as part of the hardware, and may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

[0096] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited only to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A cascade charge and discharge system for lithium battery module testing, characterized in that: The battery pack comprises a test power supply, a battery pack, a secondary charging system, a secondary battery module, a tertiary charging system and a tertiary battery module, wherein the battery pack comprises a plurality of primary battery modules, the primary battery modules, the secondary battery modules and the tertiary battery modules all comprise a plurality of battery cells, and the number of battery cells in the primary battery module is greater than the number of battery cells in the secondary battery module, and the number of battery cells in the secondary battery module is greater than the number of battery cells in the tertiary battery module; The input end of the test power supply is connected to the mains, the output end of the test power supply is connected to the battery pack, the battery pack and the secondary battery module are connected via the secondary charging system, and the secondary battery module and the tertiary battery module are connected via the tertiary battery module.

2. The cascade charge and discharge system for lithium battery module testing according to claim 1, characterized in that: The secondary charging system includes a collection circuit and a main control circuit, and the collection circuit includes an input collection circuit and an output collection circuit; The input acquisition circuit is connected between the main control circuit and the battery pack, the output acquisition circuit is connected between the main control circuit and the secondary battery module, and the main control circuit is used to be connected to the host computer; The input acquisition circuit is used to collect the first current and voltage data output by the battery pack and transmit it to the main control circuit. The output acquisition circuit is used to collect the second current and voltage data of the secondary battery module and transmit it to the main control circuit. The main control circuit is used to control the battery pack to charge or stop charging the secondary battery module based on the first current and voltage data and the second current and voltage data.

3. The cascade charge and discharge system for lithium battery module testing according to claim 2, characterized in that: The input acquisition circuit includes a first resistor, a second resistor and a third resistor, and the main control circuit includes a chip and a DC-DC parallel buck-boost topology circuit; One end of the first resistor is electrically connected to the positive electrode of the battery pack, and the other end is electrically connected to the DC-DC parallel buck-boost topology circuit; One end of the second resistor is connected between the first resistor and the battery pack, and the other end is electrically connected to the first end of the third resistor, and the second end of the third resistor is grounded; The chip includes an ISN1 pin, an ISP1 pin and a VSENSE1 pin, the ISN1 pin is connected between the first resistor and the DC-DC parallel buck-boost topology circuit, the ISP1 pin is connected between the first resistor and the second resistor, and the VSENSE1 pin is connected between the second resistor and the third resistor.

4. The cascade charge and discharge system for lithium battery module testing according to claim 3, characterized in that: The output acquisition circuit includes a fourth resistor, a fifth resistor and a sixth resistor; One end of the fourth resistor is electrically connected to the positive electrode of the secondary battery module, and the other end is electrically connected to the DC-DC parallel buck-boost topology circuit; One end of the fifth resistor is connected between the fourth resistor and the secondary battery module, and the other end is electrically connected to the first end of the sixth resistor, and the second end of the sixth resistor is grounded; The chip includes an ISN2 pin, an ISP2 pin and a VSENSE2 pin, the ISN2 pin is connected between the fourth resistor and the DC-DC parallel buck-boost topology circuit, the ISP2 pin is connected between the fourth resistor and the fifth resistor, and the VSENSE2 pin is connected between the fifth resistor and the sixth resistor.

5. The cascade charge and discharge system for lithium battery module testing according to claim 4, characterized in that: The DC-DC parallel buck-boost topology circuit includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first switch transistor, a second switch transistor, a first diode, a second diode and an inductor, and the chip also includes a PWM1 pin and a PWM2 pin; The first end of the first capacitor is connected to the first resistor, and the second end is connected to the negative electrode of the battery pack; the first end of the fourth capacitor is connected to the fourth resistor, and the second end is connected to the negative electrode of the secondary battery module; The second capacitor and the third capacitor are connected in series and then connected in parallel to the two ends of the first capacitor, a grounding wire is connected between the second capacitor and the third capacitor, the fifth capacitor and the sixth capacitor are connected in series and then connected in parallel to the two ends of the fourth capacitor, and a grounding wire is connected between the fifth capacitor and the sixth capacitor; The first switch transistor and the first diode are connected in series and then connected in parallel to the two ends of the first capacitor, the emitter of the first switch transistor is connected to the cathode of the first diode, the collector is connected to the first end of the first capacitor, the base is connected to the PWM1 pin, and the anode of the first diode is connected to the second end of the first capacitor; The second switch transistor and the second diode are connected in series and then connected in parallel to the two ends of the fourth capacitor, the emitter of the second switch transistor is connected to the cathode of the second diode, the collector is connected to the first end of the fourth capacitor, the base is connected to the PWM2 pin, and the anode of the second diode is connected to the second end of the fourth capacitor; One end of the inductor is connected between the first switch transistor and the first diode, and the other end of the inductor is connected between the second switch transistor and the second diode.

6. The cascade charge and discharge system for lithium battery module testing according to claim 5, characterized in that: It also includes a first fuse and a second fuse, wherein the first fuse is arranged between the positive electrode of the battery pack and the input acquisition circuit, and the second fuse is arranged between the positive electrode of the secondary battery module and the output acquisition circuit.

7. The cascade charge and discharge system for lithium battery module testing according to any one of claims 2 to 6, characterized in that: The circuit structure of the three-stage charging system is the same as the circuit structure of the two-stage charging system.

8. A cascade charge and discharge method for lithium battery module testing, characterized in that: A cascade charging and discharging system for testing a lithium battery module as claimed in any one of claims 1 to 7, the cascade charging and discharging system comprising a test power supply, a battery pack, a secondary charging system, a secondary battery module, a tertiary charging system and a tertiary battery module, the method comprising: Charging the battery pack via the test power supply; After the battery pack is fully charged, the secondary battery module is charged through the battery pack and the secondary charging system; charging the tertiary battery module through the secondary battery module and the tertiary charging system; Controlling the discharge of the three-stage battery module.

9. The cascade charge and discharge method for lithium battery module testing according to claim 8, characterized in that: The secondary charging system includes a collection circuit and a main control circuit, the collection circuit includes an input collection circuit and an output collection circuit, and the main control circuit includes a chip and a DC-DC parallel buck-boost topology circuit; The charging of the secondary battery module by the battery pack and the secondary charging system specifically includes: Collecting first current and voltage data output by the battery pack through the input acquisition circuit, and transmitting the first current and voltage data to the main control circuit; Collecting second current and voltage data of the secondary battery module through the output acquisition circuit, and transmitting the second current and voltage data to the main control circuit; According to the first current and voltage data and the second current and voltage data, a driving signal is generated by the chip, and the driving signal is transmitted to the DC-DC parallel buck-boost topology circuit, wherein the driving signal includes a boost signal and a buck signal; According to the driving signal, the charging voltage of the secondary battery module is adjusted by the DC-DC parallel buck-boost topology circuit.

10. The cascade charge and discharge method for lithium battery module testing according to claim 9, characterized in that: Generating a driving signal through the chip according to the first current and voltage data and the second current and voltage data specifically includes: When the voltage of the battery pack is greater than the voltage of the secondary battery module, a voltage reduction signal is generated by the chip; When the voltage of the battery pack is lower than the voltage of the secondary battery module, a boost signal is generated by the chip; The step of adjusting the charging voltage of the secondary battery module by the DC-DC parallel buck-boost topology circuit according to the driving signal specifically includes: When the driving signal is a boost signal, the DC-DC parallel buck-boost topology circuit is used for boosting, and at this time, the secondary charging system charges the secondary battery module; When the driving signal is a buck signal, the voltage is reduced by the DC-DC parallel buck-boost topology circuit. At this time, the secondary charging system stops charging the secondary battery module.

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