Charging protection circuit of lithium iron phosphate battery

Abstract

The utility model discloses a charging protection circuit of a lithium iron phosphate battery, which relates to the technical field of lithium iron phosphate batteries, and comprises a power supply module used for accessing electric energy; the power adjusting module is used for voltage sampling and adjusting the voltage of the sampled signal; the charging control module is matched with the power regulation module to carry out constant-current and constant-voltage regulation control; the first battery module is used for storing energy and stopping charging when the battery is fully charged; the second battery module is connected with the first battery module in series, stores energy and stops charging when being fully charged; the first detection module is used for carrying out full charge detection on the first battery module; and the second detection module is used for carrying out full charge detection on the second battery module. The charging protection circuit of the lithium iron phosphate battery can perform constant-current and constant-voltage charging control, prevents the first battery module and the second battery module which are connected in series from being overcharged, and automatically stops charging when the first battery module and the second battery module are fully charged, so that the service life of the lithium iron phosphate battery is prolonged, and the charging safety of the lithium iron phosphate battery is improved.

Description

Technical Field

[0001] This utility model relates to the field of lithium iron phosphate battery technology, specifically a charging protection circuit for lithium iron phosphate batteries. Background Technology

[0002] Lithium iron phosphate (LiFePO4) batteries are lithium-ion batteries that use lithium iron phosphate (LiFePO4) as the positive electrode material and carbon as the negative electrode material. To meet the charging requirements of LiFePO4 batteries in series, existing charging protection circuits for LiFePO4 batteries generally use related charging chips to charge the series-connected LiFePO4 batteries and automatically disconnect the power when the series-connected LiFePO4 batteries are fully charged. However, due to certain performance differences among individual LiFePO4 batteries, the time it takes for the individual LiFePO4 batteries in series to fully charge is different, which leads to overcharging of the first LiFePO4 battery to fully charge, thereby reducing the lifespan of the series-connected LiFePO4 batteries. Therefore, improvements are needed. Utility Model Content

[0003] This utility model provides a charging protection circuit for a lithium iron phosphate battery to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] A charging protection circuit for a lithium iron phosphate battery includes: a power supply module, a charging control module, a first battery module, a second battery module, a first detection module, a second detection module, and a power regulation module.

[0006] The power module is used to connect to DC power.

[0007] A power regulation module, connected to the power supply module, the first detection module, and the second detection module, is used to sample the voltage of DC power and output a first sampling signal. When a first full charge signal is received from the first detection module or a second full charge signal is received from the second detection module, the voltage of the first sampling signal is reduced.

[0008] The charging control module is connected to the power module, power adjustment module, first battery module and second battery module. It is used to detect the power and current of the first battery module and the second battery module in series, receive the first sampling signal and perform constant voltage and constant current regulation on the DC power according to the voltage value of the detected signal and the received signal, and output the first power. It also adjusts the voltage and current values ​​of the first power according to the voltage value of the first sampling signal.

[0009] The first battery module is connected to the second detection module and is used to store the first electrical energy and stop the energy storage operation when it receives the first full charge signal, and stop receiving the first full charge signal when it receives the second full charge signal.

[0010] The second battery module is connected to the first detection module and the first battery module. It is used to connect in series with the first battery module and store the first electrical energy transmitted by the first battery module. When the second full charge signal is received, the energy storage operation is stopped. When the first full charge signal is received, the second full charge signal is stopped.

[0011] The first detection module is connected to the first battery module and is used to detect the power level of the first battery module and output a first full charge signal when the detected power level signal is greater than the full charge threshold.

[0012] The second detection module is connected to the second battery module and is used to detect the power level of the second battery module and output a second full charge signal when the detected power level signal is greater than the full charge threshold.

[0013] As a further embodiment of this utility model: the power module includes a power interface and a first capacitor; the charging control module includes a first switching transistor, a first resistor, a second resistor, a first power transistor, a ninth resistor, an eighth resistor, a tenth resistor, a first comparator, a second comparator, a sixth resistor, a seventh resistor, and a fifth diode;

[0014] Preferably, the first end of the power interface is connected to the anode of the fifth diode and connected to the second end of the power interface, the emitter of the first switching transistor, one end of the first resistor, the source of the first power transistor, and ground through the first capacitor. The collector of the first switching transistor is connected to the other end of the first resistor, the gate of the black wing power transistor is connected to the output of the first comparator through the second resistor, the non-inverting end of the first comparator is connected to the power adjustment module and connected to one end of the ninth resistor and the inverting end of the second comparator through the eighth resistor, the non-inverting end of the second comparator is connected to the first end of the tenth resistor and connected to the first end of the sixth resistor and the inverting end of the first comparator through the seventh resistor, the second end of the tenth resistor is connected to the other end of the ninth resistor and the drain of the first power transistor, and the second end of the sixth resistor is connected to the cathode of the fifth diode and the first battery module.

[0015] As a further embodiment of this utility model: the power regulation module includes a third resistor, a fourth resistor, a fifth resistor, and a second switching transistor;

[0016] Preferably, one end of the fourth resistor is connected to the non-inverting terminal of the first comparator and the collector of the second switching transistor, and is connected to the first terminal of the power interface through the third resistor. The other end of the fourth resistor is connected to the first terminal of the tenth resistor and is connected to the emitter of the second switching transistor through the fifth resistor. The base of the second switching transistor is connected to the first detection module and the second detection module.

[0017] As a further embodiment of this utility model: the first battery module includes a first thyristor, a first battery, and a third switching transistor;

[0018] Preferably, one end of the first thyristor is connected to the first terminal of the first battery, the cathode of the fifth diode, and the first detection module; the other end of the first thyristor is connected to the second terminal of the first battery; the control terminal of the first thyristor is connected to the collector of the third switching transistor; the emitter of the third switching transistor is grounded; and the base of the third switching transistor is connected to the second detection module.

[0019] As a further improvement of this utility model: the first detection module includes an eleventh resistor, a twelfth resistor, a thirteenth resistor, a first diode, and a second diode;

[0020] Preferably, one end of the eleventh resistor is connected to the first end of the first battery, the other end of the eleventh resistor is connected to one end of the thirteenth resistor and connected to the second end of the first battery through the twelfth resistor, the other end of the thirteenth resistor is connected to the cathode of the first diode, the anode of the first diode is connected to the collector of the third switch, the anode of the second diode and the second battery module, and the cathode of the second diode is connected to the base of the second switch and the second detection module.

[0021] As a further embodiment of this utility model: the second battery module includes a second thyristor, a second battery, and a fourth switching transistor; the second detection module includes a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a third diode, and a fourth diode;

[0022] Preferably, one end of the second thyristor is connected to the first end of the second battery and one end of the fourteenth resistor. The other end of the fourteenth resistor is connected to one end of the fifteenth resistor and connected to the cathode of the third diode through the sixteenth resistor. The other end of the fifteenth resistor is connected to the second end of the second battery, the other end of the second thyristor, and the first end of the tenth resistor. The anode of the third diode is connected to the base of the third switch, the collector of the fourth switch, and the control terminal of the second thyristor. The emitter of the fourth switch is grounded. The base of the fourth switch is connected to the collector of the third switch. The cathode of the fourth diode is connected to the base of the second switch.

[0023] Compared with the prior art, the beneficial effects of this utility model are as follows: The charging protection circuit of the lithium iron phosphate battery of this utility model can use the charging control module in conjunction with the power adjustment module to perform constant current and constant voltage charging control on the first and second battery modules in series. When the first or second detection module detects that the first or second battery module is fully charged in advance, it will control the fully charged first or second battery module to stop charging. At the same time, the charging power of the charging control module is adjusted by the power adjustment module to meet the charging control of the first or second battery module that is not fully charged, thereby avoiding overcharging of the first and second battery modules in series. When both are fully charged, charging will automatically stop, thereby improving the service life and charging safety of the lithium iron phosphate battery. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic block diagram of a charging protection circuit for a lithium iron phosphate battery, provided as an example of this utility model.

[0026] Figure 2 A circuit diagram of a charging protection circuit for a lithium iron phosphate battery provided as an example of this utility model.

[0027] Figure 3 The connection circuit diagram of the second detection module provided for this utility model embodiment. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] In one embodiment, see Figure 1 A charging protection circuit for a lithium iron phosphate battery includes: a power module 1, a charging control module 2, a first battery module 3, a second battery module 4, a first detection module 5, a second detection module 6, and a power regulation module 7.

[0030] Specifically, power module 1 is used to connect to DC power;

[0031] The power adjustment module 7 is connected to the power supply module 1, the first detection module 5, and the second detection module 6. It is used to sample the voltage of DC power and output a first sampling signal. When it receives the first full charge signal output by the first detection module 5 or the second full charge signal output by the second detection module 6, it reduces the voltage of the first sampling signal.

[0032] The charging control module 2 is connected to the power module 1, the power adjustment module 7, the first battery module 3, and the second battery module 4. It is used to detect the power and current of the first battery module 3 and the second battery module 4 in series, receive the first sampling signal, and perform constant voltage and constant current regulation on the DC power according to the voltage value of the detected signal and the received signal, and output the first power. It also adjusts the voltage and current values ​​of the first power according to the voltage value of the first sampling signal.

[0033] The first battery module 3 is connected to the second detection module 6 and is used to store the first electrical energy and stop the energy storage operation when it receives the first full charge signal, and stop receiving the first full charge signal when it receives the second full charge signal.

[0034] The second battery module 4 is connected to the first detection module 5 and the first battery module 3. It is used to connect in series with the first battery module 3 and store the first electrical energy transmitted by the first battery module 3. When the second full charge signal is received, the energy storage operation is stopped. When the first full charge signal is received, the second full charge signal is stopped.

[0035] The first detection module 5 is connected to the first battery module 3 and is used to detect the power level of the first battery module 3 and output a first full charge signal when the detected power level signal is greater than the full charge threshold.

[0036] The second detection module 6 is connected to the second battery module 4 and is used to detect the power level of the second battery module 4 and output a second full charge signal when the detected power level signal is greater than the full charge threshold.

[0037] In a specific embodiment, the power module 1 can be a power circuit composed of a power interface and a capacitor, which can receive AC power and perform filtering; the charging control module 2 can be a charging control circuit composed of a comparator, resistor, field-effect transistor, transistor, etc., which can sample the current and charge of the first battery module 3 and the second battery module 4 connected in series, and compare them with the signal sampled by the power adjustment module 7, and then perform constant current and constant voltage regulation on the received DC power; the first battery module 3 can be a first battery circuit composed of a single lithium iron phosphate battery, a silicon controlled rectifier and a transistor, which can perform energy storage and stop charging when the first detection module 5 detects that it is fully charged; The second battery module 4 can be a second battery circuit composed of a single lithium iron phosphate battery, a silicon controlled rectifier (SCR), and a transistor. It can perform energy storage and stop charging when the second detection module 6 detects that it is fully charged. The first detection module 5 can be a first detection circuit composed of a resistor and a diode. It can sample the charge level of the first battery module 3 and detect when it is fully charged. The second detection module 6 can be a second detection circuit composed of a resistor and a diode. It can sample the charge level of the second battery module 4 and detect when it is fully charged. The power adjustment module 7 can be a power adjustment circuit composed of a transistor and a resistor. It can sample the DC power and adjust the voltage division value, that is, adjust the voltage value of the sampled signal.

[0038] In another embodiment, please refer to Figure 1 , Figure 2 and Figure 3 The power module 1 includes a power interface and a first capacitor C1; the charging control module 2 includes a first switching transistor V1, a first resistor R1, a second resistor R2, a first power transistor Q1, a ninth resistor R9, an eighth resistor R8, a tenth resistor R10, a first comparator A1, a second comparator A2, a sixth resistor R6, a seventh resistor R7, and a fifth diode D5.

[0039] Specifically, the first end of the power interface is connected to the anode of the fifth diode D5 and connected to the second end of the power interface, the emitter of the first switching transistor V1, one end of the first resistor R1, the source of the first power transistor Q1, and the ground through the first capacitor C1. The collector of the first switching transistor V1 is connected to the other end of the first resistor R1 and the gate of the black wing power transistor and connected to the output of the first comparator A1 through the second resistor R2. The non-inverting end of the first comparator A1 is connected to the power adjustment module 7 and connected to one end of the ninth resistor R9 and the inverting end of the second comparator A2 through the eighth resistor R8. The non-inverting end of the second comparator A2 is connected to the first end of the tenth resistor R10 and connected to the first end of the sixth resistor R6 and the inverting end of the first comparator A1 through the seventh resistor R7. The second end of the tenth resistor R10 is connected to the other end of the ninth resistor R9 and the drain of the first power transistor Q1. The second end of the sixth resistor R6 is connected to the cathode of the fifth diode D5 and the first battery module 3.

[0040] In a specific embodiment, the first switching transistor V1 can be an NPN transistor; the first power transistor Q1 can be an N-channel MOSFET; the first comparator A1 and the second comparator A2 can both be LM358 comparators, with the first comparator A1 for voltage regulation and the second comparator A2 for current regulation; and the tenth resistor R10 for current sampling.

[0041] Furthermore, the power regulation module 7 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a second switch V2;

[0042] Specifically, one end of the fourth resistor R4 is connected to the non-inverting terminal of the first comparator A1 and the collector of the second switching transistor V2, and is connected to the first terminal of the power interface through the third resistor R3. The other end of the fourth resistor R4 is connected to the first terminal of the tenth resistor R10, and is connected to the emitter of the second switching transistor V2 through the fifth resistor R5. The base of the second switching transistor V2 is connected to the first detection module 5 and the second detection module 6.

[0043] In a specific embodiment, the third resistor R3 and the fourth resistor R4 perform voltage division sampling of DC power; the second switch V2 can be an NPN transistor, which, together with the fifth resistor R5, reduces the voltage value of the first sampling signal.

[0044] Furthermore, the first battery module 3 includes a first thyristor S1, a first battery, and a third switching transistor V3;

[0045] Specifically, one end of the first thyristor S1 is connected to the first end of the first battery, the cathode of the fifth diode D5, and the first detection module 5. The other end of the first thyristor S1 is connected to the second end of the first battery. The control end of the first thyristor S1 is connected to the collector of the third switch V3. The emitter of the third switch V3 is grounded. The base of the third switch V3 is connected to the second detection module 6.

[0046] In a specific embodiment, the first thyristor S1 can be a bidirectional thyristor; the first battery can be a single lithium iron phosphate battery; and the third switch V3 can be an NPN transistor.

[0047] Furthermore, the first detection module 5 includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a first diode D1, and a second diode D2;

[0048] Specifically, one end of the eleventh resistor R11 is connected to the first end of the first battery, the other end of the eleventh resistor R11 is connected to one end of the thirteenth resistor R13 and connected to the second end of the first battery through the twelfth resistor R12, the other end of the thirteenth resistor R13 is connected to the cathode of the first diode D1, the anode of the first diode D1 is connected to the collector of the third switch V3, the anode of the second diode D2 and the second battery module 4, and the cathode of the second diode D2 is connected to the base of the second switch V2 and the second detection module 6.

[0049] In a specific embodiment, the thirteenth resistor R13 and the first diode D1 are set to the full-charge threshold; the eleventh resistor R11 and the twelfth resistor R12 are used for power sampling.

[0050] Furthermore, the second battery module 4 includes a second thyristor S2, a second battery, and a fourth switch V4; the second detection module 6 includes a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a third diode D3, and a fourth diode D4.

[0051] Specifically, one end of the second thyristor S2 is connected to the first end of the second battery and one end of the fourteenth resistor R14. The other end of the fourteenth resistor R14 is connected to one end of the fifteenth resistor R15 and is connected to the cathode of the third diode D3 through the sixteenth resistor R16. The other end of the fifteenth resistor R15 is connected to the second end of the second battery, the other end of the second thyristor S2, and the first end of the tenth resistor R10. The anode of the third diode D3 is connected to the base of the third switch V3, the collector of the fourth switch V4, and the control terminal of the second thyristor S2. The emitter of the fourth switch V4 is grounded. The base of the fourth switch V4 is connected to the collector of the third switch V3. The cathode of the fourth diode D4 is connected to the base of the second switch V2.

[0052] In a specific embodiment, the sixteenth resistor R16 and the third diode D3 are used to set the full-charge threshold; the fourteenth resistor R14 and the fifteenth resistor are used for power sampling; the second thyristor S2 can be a bidirectional thyristor; the second battery can be a single lithium iron phosphate battery; and the fourth switch V4 can be an NPN transistor.

[0053] In this embodiment, a charging protection circuit for a lithium iron phosphate battery includes a DC power input via a power interface. A first capacitor C1 filters the DC power. Resistors R3 and R4 sample the DC power voltage. Resistors R6 and R7 sample the charge levels of the first and second batteries connected in series. A first comparator A1 triggers the first power transistor Q1 to conduct. A tenth resistor R10 samples the current. These components, along with the eighth resistor R8, the nineteenth resistor, and the second comparator A2, control the conduction state of the first switching transistor V1. This adjusts the conduction state of the first power transistor Q1 to perform constant voltage and constant current regulation of the DC power, outputting the first power and controlling the charging of the first and second batteries. Simultaneously, if the first battery is charging faster than the second... The first battery is fully charged first. The eleventh resistor R11 and the twelfth resistor R12 sample the charge of the first battery. The sampled signal is greater than the full charge threshold set by the thirteenth resistor R13 and the first diode D1, which turns on the second switch V2, the fourth switch V4 and the first thyristor S1. The fifth resistor R5 is connected in parallel with the fourth resistor R4, thereby adjusting the output power of the charging control module 2 and satisfying the charging control of the second battery. When the second battery module 4 is fully charged, the first comparator A1 will stop controlling the first power transistor Q1 to work, and then stop the charging operation. Similarly, when the second battery is fully charged before the first battery, the charging control module 2 will provide the first battery with the first power separately, and stop the charging operation after the first battery is fully charged.

[0054] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0055] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A charging protection circuit of a lithium iron phosphate battery, characterized in that, the charging protection circuit of the lithium iron phosphate battery comprises a power supply module, a charging control module, a first battery module, a second battery module, a first detection module, a second detection module and a power adjustment module; the power supply module is configured to access direct current energy; the power adjustment module is connected to the power supply module, the first detection module and the second detection module, configured to sample the voltage of the direct current energy and output a first sampling signal, and reduce the voltage of the first sampling signal when receiving a first full power signal output by the first detection module or a second full power signal output by the second detection module; the charging control module is connected to the power supply module, the power adjustment module, the first battery module and the second battery module, configured to detect the electric quantity and the current of the first battery module and the second battery module in series, receive the first sampling signal and adjust the voltage and the current of the direct current energy according to the voltage values of the detected signal and the received signal, and output a first electric energy, and adjust the voltage value and the current value of the first electric energy according to the voltage value of the first sampling signal; the first battery module is connected to the second detection module, configured to store the first electric energy and stop the energy storage work when receiving the first full power signal, and stop receiving the first full power signal when receiving the second full power signal; the second battery module is connected to the first detection module and the first battery module, configured to be connected in series with the first battery module and store the first electric energy transmitted by the first battery module, stop the energy storage work when receiving the second full power signal, and stop receiving the second full power signal when receiving the first full power signal; the first detection module is connected to the first battery module, configured to detect the electric quantity of the first battery module and output the first full power signal when the detected electric quantity signal is greater than a full power threshold value; the second detection module is connected to the second battery module, configured to detect the electric quantity of the second battery module and output the second full power signal when the detected electric quantity signal is greater than the full power threshold value.

2. The charge protection circuit for a lithium iron phosphate battery of claim 1, wherein, the power supply module comprises a power supply interface and a first capacitor; the charging control module comprises a first switch tube, a first resistor, a second resistor, a first power tube, a ninth resistor, an eighth resistor, a tenth resistor, a first comparator, a second comparator, a sixth resistor, a seventh resistor and a fifth diode. The first end of the power interface is connected to the anode of the fifth diode and the second end of the power interface is connected to the emitter of the first switch tube, one end of the first resistor, the source of the first power tube and the ground end through the first capacitor, the collector of the first switch tube is connected to the other end of the first resistor and the gate of the first power tube through the second resistor, the output end of the first comparator is connected to the gate of the first power tube through the second resistor, the non-inverting end of the second comparator is connected to the other end of the ninth resistor and the inverting end of the first comparator through the eighth resistor, the inverting end of the second comparator is connected to the first end of the tenth resistor and the non-inverting end of the first comparator through the seventh resistor, the second end of the tenth resistor is connected to the other end of the ninth resistor and the drain of the first power tube, the second end of the sixth resistor is connected to the cathode of the fifth diode and the first battery module.

3. The charge protection circuit for a lithium iron phosphate battery of claim 2, wherein, The power regulating module comprises a third resistor, a fourth resistor, a fifth resistor and a second switch tube; The non-inverting end of the first comparator and the collector of the second switch tube are connected to one end of the fourth resistor through the third resistor, the first end of the power interface is connected to the other end of the fourth resistor, the first end of the tenth resistor is connected to the other end of the fourth resistor through the fifth resistor, and the emitter of the second switch tube is connected to the second end of the tenth resistor, the base of the second switch tube is connected to the first detection module and the second detection module.

4. The charge protection circuit for a lithium iron phosphate battery of claim 3, wherein, The first battery module comprises a first thyristor, a first battery and a third switch tube; One end of the first thyristor is connected to the first end of the first battery, the cathode of the fifth diode and the first detection module, the other end of the first thyristor is connected to the second end of the first battery, the control end of the first thyristor is connected to the collector of the third switch tube, the emitter of the third switch tube is grounded, and the base of the third switch tube is connected to the second detection module.

5. The charge protection circuit for a lithium iron phosphate battery of claim 4, wherein, The first detection module comprises an eleventh resistor, a twelfth resistor, a thirteenth resistor, a first diode and a second diode; One end of the eleventh resistor is connected to the first end of the first battery, the other end of the eleventh resistor is connected to one end of the thirteenth resistor through the twelfth resistor and the second end of the first battery, the other end of the thirteenth resistor is connected to the cathode of the first diode, the anode of the first diode is connected to the collector of the third switch tube, the anode of the second diode and the second battery module, and the cathode of the second diode is connected to the base of the second switch tube and the second detection module.

6. The charge protection circuit for a lithium iron phosphate battery of claim 5, wherein, The second battery module comprises a second thyristor, a second battery and a fourth switch tube; the second detection module comprises a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a third diode and a fourth diode; One end of the second thyristor is connected to the first end of the second battery and one end of the fourteenth resistor, the other end of the fourteenth resistor is connected to one end of the fifteenth resistor through the sixteenth resistor and the cathode of the third diode, the other end of the fifteenth resistor is connected to the second end of the second battery, the other end of the second thyristor and the first end of the tenth resistor, the anode of the third diode is connected to the base of the third switch tube, the collector of the fourth switch tube and the control end of the second thyristor, the emitter of the fourth switch tube is grounded, the base of the fourth switch tube is connected to the collector of the third switch tube, and the cathode of the fourth diode is connected to the base of the second switch tube.

Images