Battery pack equalization protection system

Abstract

The utility model relates to a battery pack equalization protection system, which comprises an MCU master control module, an analog front-end module, an MOS tube module, an equalization control module and an equalization function module, the battery pack is formed by connecting a plurality of batteries in series, the equalization function module is provided with single equalization unit circuits, and the number of the single equalization unit circuits corresponds to that of the batteries. Each battery is provided with a single-section equalization unit circuit, and the multiple single-section equalization unit circuits are connected in series so as to carry out equalization charging on the multiple batteries at the same time; according to the utility model, the technical problems of low equalization efficiency and poor equalization effect of the battery pack in the prior art can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery balancing, and in particular to a battery pack balancing protection system. Background Art

[0002] At present, the application of multiple groups of lithium batteries in parallel or in series is becoming more and more widespread. In practical applications, the inconsistency of each group of lithium batteries leads to differences in the capacity of the battery cells, which shortens the battery life. Most of the current balancing methods on the market use small current passive energy consumption, and the balancing current ranges from 20-200mA. There are also some inefficient active balancing methods, which start one battery each time for balancing. After one battery is balanced, the next battery can be balanced. The efficiency is relatively low and cannot meet the balancing effect of actual use.

[0003] Therefore, it is necessary to provide a technical solution that can solve the above problems. Utility Model Content

[0004] The utility model aims to provide a battery pack balancing protection system to solve the technical problems of low battery pack balancing efficiency and poor balancing effect in the prior art.

[0005] The technical solution provided by the utility model is:

[0006] A battery pack balancing protection system, comprising an MCU main control module, an analog front-end module, a MOS tube module, a balancing control module and a balancing function module, wherein the analog front-end module is connected to a battery pack, the MOS tube module is connected to a negative output terminal B- of the battery pack through a current sensing resistor, the analog front-end module is connected to both ends of the current sensing resistor, the MOS tube module is also connected to the analog front-end module, and the analog front-end module MCU main control module, the balancing control module, the balancing function module and the battery pack are connected in sequence;

[0007] The battery pack is composed of multiple batteries connected in series, and the balancing function module is provided with single-cell balancing unit circuits corresponding to the number of the batteries, each battery is configured with a single-cell balancing unit circuit, and multiple single-cell balancing unit circuits are connected in series to balance and charge multiple batteries simultaneously;

[0008] The single-section balancing unit circuit includes an isolation transformer, a primary input circuit connected to the primary coil of the isolation transformer, a voltage balancing circuit connected to the feedback coil of the isolation transformer, and a current balancing circuit connected to the balancing output coil of the isolation transformer.

[0009] In a preferred embodiment, the voltage balancing circuit includes a PWM power switch chip; preferably, the model of the PWM power switch chip is MK2768.

[0010] In a preferred embodiment, the current balancing circuit includes a synchronous rectification control chip; preferably, the synchronous rectification control chip model is JW7700.

[0011] In a preferred embodiment, the balancing control module includes a balancing switch control circuit for controlling the switch state of the single-cell balancing unit circuit, and a balancing power supply control circuit for providing power to the balancing function module.

[0012] In a preferred embodiment, the balancing switch control circuit includes an optocoupler, the input end of the optocoupler is controlled by the balancing power supply control circuit, and the output end of the optocoupler is connected to a first switch circuit for controlling the switch state of the single-cell balancing unit circuit.

[0013] In a preferred embodiment, the balanced power supply control circuit includes a second switch circuit for controlling the power supply state of the balanced functional module, and a balanced control port expansion circuit for expanding the MUC port, and the second switch circuit is controlled by the MCU main control module.

[0014] In a preferred implementation, the balance control port expansion circuit includes a shift register, and the chip model of the shift register is 74HC595.

[0015] In a preferred embodiment, the MOS tube module includes a charging MOS tube QC and a discharging MOS tube QD, the gates of the charging MOS tube QC and the discharging MOS tube QD are connected to the analog front-end module, the source of the discharging MOS tube QD is connected to the current sensing resistor, and the drain of the discharging MOS tube QD is connected to the drain of the charging MOS tube QC.

[0016] Compared with the prior art, the utility model does not need to frequently switch the battery for charging, but charges the batteries that need balanced charging together, and the current of balanced charging is large, thereby effectively improving the balanced time and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic block diagram of the circuit structure of the battery pack balancing protection system according to an embodiment of the utility model;

[0018] Figure 2 This is a schematic block diagram of the circuit structure of the MOS tube module described in the embodiment of the utility model;

[0019] Figure 3 It is a specific circuit diagram of a single-section equalization unit circuit in the equalization function module described in the embodiment of the utility model;

[0020] Figure 4A specific circuit diagram of the balancing switch control circuit described in the embodiment of the utility model;

[0021] Figure 5 A specific circuit diagram of the balanced power supply control circuit described in the embodiment of the utility model;

[0022] Figure 6 It is a connection diagram of the balancing function module and the balancing switch control circuit in the embodiment of the utility model;

[0023] Figure 7 A specific circuit diagram of the analog front-end module described in the embodiment of the utility model;

[0024] Figure 8 It is a specific circuit diagram of the MCU main control module described in the embodiment of the utility model.

[0025] The figures in the drawings are:

[0026] 10. Battery pack; 20. Analog front-end module; 30. MCU main control module; 40. Current sensing resistor; 50. MOS tube module; 60. Balance function module; 61. Isolation transformer; 62. Primary input circuit; 63. Voltage balance circuit; 64. Current balance circuit; 70. Balance control module; 71. Balance switch control circuit; 711. First switch circuit; 72. Balance power supply control circuit; 721. Second switch circuit; 722. Balance control port expansion circuit. DETAILED DESCRIPTION

[0027] In order to better understand the purpose, technical solution and technical effect of the utility model, the utility model is further explained in conjunction with the accompanying drawings and embodiments. At the same time, it is stated that the embodiments described below are only used to explain the utility model and are not used to limit the utility model.

[0028] Example 1

[0029] like Figure 1-8 As shown, a battery pack balancing protection system includes an MCU main control module 30, an analog front-end module 20, a MOS tube module 50, a balancing control module 70 and a balancing function module 60, wherein the analog front-end module 20 is connected to the battery pack 10, the MOS tube module 50 is connected to the negative output terminal B- of the battery pack 10 through the current sensing resistor 40, the analog front-end module 20 is connected to both ends of the current sensing resistor 40, the MOS tube module 50 is also connected to the analog front-end module 20, and the analog front-end module 20, the MCU main control module 30, the balancing control module 70, the balancing function module 60 and the battery pack 10 are connected in sequence;

[0030] The battery pack 10 is composed of multiple batteries connected in series, and the balancing function module 60 is provided with a number of single-cell balancing unit circuits corresponding to the number of batteries, each battery is configured with a single-cell balancing unit circuit, and multiple single-cell balancing unit circuits are connected in series to balance and charge multiple batteries simultaneously;

[0031] The single-section balancing unit circuit includes an isolation transformer 61, a primary input circuit 62 connected to the primary coil of the isolation transformer 61, a voltage balancing circuit 63 connected to the feedback coil of the isolation transformer 61, and a current balancing circuit 64 connected to the balancing output coil of the isolation transformer 61.

[0032] In this embodiment, the analog front-end module 20 is used to detect and collect information of the battery pack 10, such as collecting battery information such as battery voltage, current, and temperature, and transmit the battery information obtained by detection and collection to the MCU main control module 30. The MCU main control module 30 controls the corresponding functional module to turn on or off balanced charging of the battery according to the received battery information. At the same time, the MCU main control module 30 is also used to realize functions such as overvoltage protection and overcurrent protection; the MOS tube module 50 includes a charging MOS tube QC and a discharging MOS tube QD. The gates of the charging MOS tube QC and the discharging MOS tube QD are connected to the analog front-end module 20, the source of the discharging MOS tube QD is connected to the current detection resistor 40, and the drain of the discharging MOS tube QD is connected to the drain of the charging MOS tube QC. Figure 2 The MOS tube module is a functional module existing in the prior art or a functional module that can be realized in the prior art, and its specific composition and working principle will not be further described here.

[0033] It should be noted that the analog front-end module 20 and the MCU main control module 30 are functional modules existing in the prior art or functional modules that can be implemented in the prior art. The above-mentioned functional modules in the present application scheme do not involve improvements to computer programs or algorithms. Therefore, the specific composition and working principle of the analog front-end module 20 and the MCU main control module 30 will not be further described.

[0034] In a specific embodiment, the specific circuit diagrams of the analog front-end module 20 and the MCU main control module 30 are respectively as shown in the attached Figure 7-8 shown.

[0035] In a specific embodiment, the single-cell equalization unit circuit is as shown in the attached Figure 3As shown, in this embodiment, the isolation transformer 61 is provided with four coils, a primary coil, a feedback coil and two balanced output coils, wherein the primary input circuit 62 is connected to the primary coil, the voltage balancing circuit 63 is connected to the feedback coil, and the current balancing circuit 64 is connected to the balanced output coil; the primary input circuit 62 can support a voltage input of 30-100V, the voltage balancing circuit 63 is used for a constant balanced output voltage, and the current balancing circuit 64 is used for balanced charging current.

[0036] In a preferred embodiment, the voltage balancing circuit 63 includes a PWM power switch chip; preferably, the model of the PWM power switch chip is MK2768. The current balancing circuit 64 includes a synchronous rectification control chip; preferably, the model of the synchronous rectification control chip is JW7700. In this embodiment, the current balancing circuit 64 uses the JW7700 synchronous rectification control chip, which can improve the charging efficiency by about 10%.

[0037] Specifically, the specific circuits of the voltage balancing circuit 63 and the current balancing circuit 64 are shown in the attached Figure 3 As shown, no further description is given here.

[0038] In a preferred embodiment, the balancing control module 70 includes a balancing switch control circuit 71 for controlling the switch state of the single-cell balancing unit circuit, and a balancing power supply control circuit 72 for providing power to the balancing function module 60 .

[0039] In a preferred embodiment, the balancing switch control circuit 71 includes an optocoupler, the input end of the optocoupler is controlled by the balancing power supply control circuit 72, and the output end of the optocoupler is connected to a first switch circuit 711 for controlling the switch state of the single-section balancing unit circuit.

[0040] In a specific implementation, the balancing switch control circuit 71 is as shown in the attached Figure 4 As shown, the first switch circuit 711 includes switch devices such as MOS tube BM9 and MOS tube BM26, and the input end of the optical coupler EL357 is connected to the balanced power control circuit 72, that is, the positive electrode of the diode in the input end of the optical coupler is connected to the balanced power control circuit 72. The balanced power control circuit 72 controls the switching state of the MOS tube BM9 and the MOS tube BM26 through the optical coupler EL357, thereby controlling the switching state of the first switch circuit 711, and then controlling the switching state of the single-cell balancing unit circuit, and finally controlling the single-cell balancing unit circuit to turn on and off the balanced charging of the battery.

[0041] The connection relationship between the balancing switch control circuit 71 and the balancing function module 60 can be found in the attached Figure 6 .

[0042] In a preferred embodiment, the balanced power supply control circuit 72 includes a second switch circuit 721 for controlling the power supply state of the balanced function module 60, and a balanced control port expansion circuit 722 for expanding the MUC port, and the second switch circuit 721 is controlled by the MCU main control module 30. The balanced control port expansion circuit 722 is used to expand the port of the MCU so as to control the single-section balanced unit circuit.

[0043] In a preferred implementation, the balance control port expansion circuit 722 includes a shift register, and the chip model of the shift register is 74HC595.

[0044] In a specific implementation, the balanced power supply control circuit 72 is specifically as shown in the attached Figure 5 As shown, the second switch circuit 721 includes switch tubes such as transistor BQ1, MOS tube BM34, MOS tube BM47 and MOS tube BM48. The switch state of the second switch circuit 721 is controlled by the MCU main control module 30. The MCU main control module 30 can realize power supply to the entire balancing function module 60 by controlling the conduction of the transistor BQ1. If the MCU main control module 30 controls the conduction of the transistor BQ1, the entire balancing function module 60 is in a power-off state; when the MCU main control module 30 controls the conduction of the MOS tube BM47 and the MOS tube BM48, the balancing control port expansion circuit 722 controls the port to be expanded (specifically, it is expanded through the shift register (chip model is 74HC595)), and is used to control the single-section balancing unit circuit.

[0045] The battery pack balancing protection system provided in this embodiment is provided with a single-cell balancing unit circuit for each battery in the battery pack 10 in the balancing function module 60 according to the number of batteries in the battery pack 10, and each single-cell balancing unit circuit is provided with a current balancing circuit 64 for charging the single-cell battery; and in the balancing control module 70, a balancing switch control circuit 71 for controlling the charging state of each current balancing circuit 64 is provided, and a balancing electronic switch for independently controlling the charging state of the current balancing circuit 64 is provided in the balancing switch control circuit 71. Specifically, as shown in the attached Figure 4As shown, the first switch circuit 711 is used as a balancing electronic switch for controlling whether the current balancing circuit 64 performs balanced charging on the battery. When the analog front-end module 20 detects that the voltage of one or more single-cell batteries is low, the MCU main control module 30 sends a corresponding control signal to the balancing control module 70 to turn on the corresponding first switch circuit 711, and control the current balancing circuit 64 to perform balanced charging on the corresponding single-cell batteries, while the first switch circuits 711 corresponding to other batteries with higher voltages or normal voltages are closed, and the corresponding single-cell batteries will not be balanced charged. Finally, balanced charging of one or more single-cell batteries with lower voltages of these batteries is achieved through the total voltage drop of the battery pack 10. The balancing current can be 1A-5A. If a larger balancing current is required, the transformer power of the isolation transformer 61 in the balancing function module 60 can be adjusted according to the actual requirements of the battery pack 10 to customize a larger balancing current. During the balanced charging process, multiple strings of batteries with lower voltages can be balanced charged at the same time. For multiple strings of batteries, there is no need to frequently switch batteries for charging, but the batteries that need balanced charging can be charged together, thereby effectively improving the balancing time and efficiency, and thus effectively solving the problems of low battery pack balancing efficiency and poor balancing effect in the prior art.

[0046] For example, in a specific embodiment, it is assumed that there are 17 batteries in the battery pack 10, and the voltage of the first and second batteries in the battery pack 10 is 20mV lower than that of other single batteries. When the analog front-end module 20 detects that the voltage of the first and second batteries is 20mV lower than that of other single batteries, the MCU main control module 30 sends a corresponding control signal (such as a high-level signal) to the balancing control module 70, so that the switch tube devices in the first switch circuit 711 that controls the first and second batteries are turned on (such as MOS tube BM9 and MOS tube BM26), that is, the balancing electronic switches of the first and second batteries are both in the on-closed state, so as to reduce the total voltage of the battery pack and charge the first and second batteries evenly. As for the first switch circuit 711 corresponding to other battery cells (batteries 3 to 17), the MCU main control module 30 sends a corresponding control signal (such as a low-level signal) to the balancing control module 70, so that the switch tube devices in the first switch circuit 711 controlling the 1st and 2nd battery cells are in a disconnected state, and the total voltage of the battery pack is reduced and cannot charge the 3rd to 17th battery cells.

[0047] The above embodiments only express several implementation methods of the utility model, and the descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the inventive concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A battery pack balancing protection system, characterized in that: It includes an MCU main control module, an analog front-end module, a MOS tube module, a balancing control module and a balancing function module. The analog front-end module is connected to a battery pack. The MOS tube module is connected to a negative output terminal B- of the battery pack through a current-sensing resistor. The analog front-end module is connected to both ends of the current-sensing resistor. The MOS tube module is also connected to the analog front-end module. The analog front-end module MCU main control module, the balancing control module, the balancing function module and the battery pack are connected in sequence. The battery pack is composed of multiple batteries connected in series, and the balancing function module is provided with single-cell balancing unit circuits corresponding to the number of the batteries, each battery is configured with a single-cell balancing unit circuit, and multiple single-cell balancing unit circuits are connected in series to balance and charge multiple batteries simultaneously; The single-section balancing unit circuit includes an isolation transformer, a primary input circuit connected to the primary coil of the isolation transformer, a voltage balancing circuit connected to the feedback coil of the isolation transformer, and a current balancing circuit connected to the balancing output coil of the isolation transformer.

2. The battery pack balancing protection system according to claim 1, characterized in that: The voltage balancing circuit includes a PWM power switch chip.

3. The battery pack balancing protection system according to claim 2, characterized in that: The model of the PWM power switch chip is MK2768.

4. The battery pack balancing protection system according to claim 1, characterized in that: The current balancing circuit includes a synchronous rectification control chip.

5. The battery pack balancing protection system according to claim 4, characterized in that: The synchronous rectification control chip model is JW7700.

6. The battery pack balancing protection system according to claim 1, characterized in that: The balancing control module includes a balancing switch control circuit for controlling the switch state of the single-cell balancing unit circuit, and a balancing power supply control circuit for providing power to the balancing function module.

7. The battery pack balancing protection system according to claim 6, characterized in that: The balancing switch control circuit includes an optical coupler, the input end of the optical coupler is controlled by the balancing power supply control circuit, and the output end of the optical coupler is connected to a first switch circuit for controlling the switch state of the single-cell balancing unit circuit.

8. The battery pack balancing protection system according to claim 6, characterized in that: The balanced power supply control circuit includes a second switch circuit for controlling the power supply state of the balanced function module and a balanced control port expansion circuit for expanding the MUC port. The second switch circuit is controlled by the MCU main control module.

9. The battery pack balancing protection system according to claim 8, characterized in that: The balance control port expansion circuit includes a shift register, and the chip model of the shift register is 74HC595.

10. The battery pack balancing protection system according to claim 1, characterized in that: The MOS tube module includes a charging MOS tube QC and a discharging MOS tube QD. The gates of the charging MOS tube QC and the discharging MOS tube QD are connected to the analog front-end module, the source of the discharging MOS tube QD is connected to the current sensing resistor, and the drain of the discharging MOS tube QD is connected to the drain of the charging MOS tube QC.

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