Lithium battery protection system and mobile power supply thereof

Abstract

The utility model relates to the technical field of mobile power supplies, in particular to a lithium battery protection system and a mobile power supply thereof. Comprising a battery protection chip, a charging and discharging MOS tube, a failure protection module, a DC-DC module, a main control chip and an output module, the DC-DC module is respectively connected with the battery pack and the output module, the battery protection chip and the charging and discharging MOS tube are arranged between the battery pack and the DC-DC module, a control end of the failure protection module is connected with an output end of the main control chip, an output end of the failure protection module is connected with a control end of the charging and discharging MOS tube, the output module is provided with a sampling resistor, and the sampling resistor is connected with the battery pack. The main control chip is connected with the two ends of the sampling resistor respectively; by designing the lithium battery protection system, the charging and discharging MOS tube is closed in time and the charging and discharging loop is cut off in time when charging and discharging of the system are abnormal, a lithium battery protection chip is not needed in the control process, and the function that the charging and discharging MOS tube can be cut off in time when output voltage is abnormal in the state that a system protection mechanism fails to work so as to protect a battery cell is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of mobile power supplies, in particular to a lithium battery protection system and a mobile power supply thereof. Background Art

[0002] With the implementation of the national standard for mobile power supplies, the safety tests on mobile power supplies or energy storage and battery products are becoming more and more stringent. When the testing agency conducts a simulated failure test, any components are short-circuited (one at a time), and the test cannot exceed the maximum charging current and maximum discharging current of the battery cell. When the main control chip fails, it is necessary to rely on the lithium protection IC. In order to prevent false triggering, the lithium protection overcurrent protection is often set relatively large during design. Therefore, when the mechanism fails, the charging and discharging currents will exceed the maximum current of the battery, making it difficult to meet the requirements.

[0003] Therefore, we need to design a mechanism failure protection circuit in the above situation to ensure the safe operation of the system. Utility Model Content

[0004] The technical problem to be solved by the embodiments of the utility model is to provide a lithium battery protection system and a mobile power supply thereof, so as to solve the problem in the prior art that the charging and discharging currents will exceed the maximum current of the battery when the mechanism fails.

[0005] The utility model discloses a lithium battery protection system, which comprises: a battery protection chip, a charge and discharge MOS tube, a failure protection module, a DC-DC module, a main control chip and an output module; the voltage input end of the DC-DC module is connected to a battery pack, the voltage output end of the DC-DC module is connected to the output module, the battery protection chip and the charge and discharge MOS tube are both arranged between the battery pack and the DC-DC module, the control end of the failure protection module is connected to the output end of the main control chip, the output end of the failure protection module is connected to the control end of the charge and discharge MOS tube, a sampling resistor is arranged at the negative grounding end of the output module, and the main control chip is respectively connected to the two ends of the sampling resistor.

[0006] Optionally, the failure protection module includes a first MOS tube and a second MOS tube, the drain of the first MOS tube and the drain of the second MOS tube are both connected to the charging and discharging MOS tube, the gate of the first MOS tube and the gate of the second MOS tube are both connected to the main control chip, and the source of the first MOS tube and the source of the second MOS tube are both grounded.

[0007] Optionally, a first sampling pin and a second sampling pin are provided on the main control chip, the first sampling pin and the second sampling pin are respectively connected to two ends of the sampling resistor, and a first protection resistor is provided between the first sampling pin and the sampling resistor, and a second protection resistor is provided between the second sampling pin and the sampling resistor.

[0008] Optionally, a first pull-up resistor and a second pull-up resistor are respectively connected to the first sampling pin and the second sampling pin of the main control chip.

[0009] Optionally, a third protection resistor is provided between the output end of the DC-DC module and the output module.

[0010] Optionally, a current regulating module is further included, the input end of the current regulating module is connected to the main control module, and the output end of the current regulating module is respectively connected to two ends of the third protection resistor.

[0011] Optionally, the current regulating module includes a first voltage reference chip, a reference end and a positive electrode of the first voltage reference chip are both connected to the main control chip, and a negative electrode of the first voltage reference chip is connected to one end of the third protection resistor.

[0012] Optionally, the current regulating module further includes a second voltage reference chip, the reference end and the positive electrode of the second voltage reference chip are both connected to the main control chip, and the negative electrode of the second voltage reference chip is connected to the other end of the third protection resistor.

[0013] Optionally, a display module is further included, the display module is connected to the main control chip, and the display module includes at least one LED display light.

[0014] In order to solve the problems existing in the prior art, the utility model also provides a mobile power supply, which comprises the lithium battery protection system as described above, and also comprises a battery pack, wherein the battery pack is connected to the voltage input terminal of the DC-DC module.

[0015] Compared with the prior art, the lithium battery protection system provided by the embodiment of the utility model has the following beneficial effects: by setting a sampling resistor at the system output end, and connecting the input end of the main control chip to the two ends of the sampling resistor respectively, the voltage at the system output end is timely collected; by setting a failure protection module, and connecting the output end of the failure protection module to the control end of the charge and discharge MOS tube, and connecting the control end of the failure protection module to the output end of the main control chip, when the main control chip detects that the voltage at the system output end is abnormal, it can generate a corresponding level signal to the failure protection module to control the failure protection module to start, thereby controlling the charge and discharge MOS tube to be cut off, and the control process does not require the help of the lithium battery protection chip, and realizes the function of timely cutting off the charge and discharge MOS tube to protect the battery cell when the output voltage is abnormal even when the system protection mechanism fails. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The technical solution of the utility model will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0017] Figure 1 This is a system block diagram of a lithium battery protection system provided by an embodiment of the utility model;

[0018] Figure 2 is a circuit diagram of a failure protection module provided by an embodiment of the utility model;

[0019] Figure 3 It is a circuit diagram of the main control chip provided by the embodiment of the utility model;

[0020] Figure 4 It is a circuit diagram of a sampling resistor provided by an embodiment of the utility model;

[0021] Figure 5 is a circuit diagram of a current regulating module provided by an embodiment of the utility model;

[0022] Figure 6 It is a circuit diagram of a display module provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, a preferred embodiment of the present utility model is described in detail.

[0024] like Figures 1 to 6 As shown, the utility model provides a specific embodiment of a lithium battery protection system.

[0025] A lithium battery protection system, reference Figure 1The lithium battery protection system includes: a battery protection chip 100, a charge and discharge MOS tube 200, a failure protection module 300, a DC-DC module 400, a main control chip 500 and an output module 600.

[0026] Among them, reference Figure 1 The voltage input end of the DC-DC module is connected to the battery pack, and the voltage output end of the DC-DC module 400 is connected to the output module 600 for conversion between different voltage levels, converting high DC voltage into low DC voltage, or converting low DC voltage into high DC voltage, so as to realize internal charging or external power supply; the main control chip 500 is a system MCU, which is used for whole machine control and charging and discharging protection and management of the battery pack; the battery protection chip 100 and the charging and discharging MOS tube 200 are both arranged in the loop between the battery pack and the DC-DC module 400, and the charging and discharging MOS tube 200 is a charging and discharging pair MOS, which serves as a charging or discharging switch.

[0027] Further, refer to Figure 1 The battery protection chip 100 is used for monitoring and management during the charging and discharging process of the lithium battery, which includes functions such as overcharge protection, over-discharge protection, overcurrent protection, temperature protection, short circuit protection and balanced charging and discharging. Generally speaking, when the main control chip 500 fails, it is necessary to rely on the lithium battery protection IC. In order to prevent false triggering, the overcurrent protection set by the lithium battery protection IC is often relatively large. Therefore, when the lithium battery protection IC triggers the overcurrent protection, the actual charging and discharging current has far exceeded the maximum current of the battery. With the implementation of a series of new national standards, the charging and discharging safety test of rechargeable and dischargeable products is more stringent. It is necessary to ensure that the charging and discharging current does not exceed the maximum charging current of the battery cell during the test. The overcurrent protection set by the lithium battery protection IC is relatively large, and it is impossible to cut off the charging and discharging circuit in time when the charging and discharging current exceeds the maximum current of the battery to ensure the safe operation of the system.

[0028] To solve the above problems, refer to Figure 1 The lithium battery protection system is also provided with a failure protection module 300. The control end of the failure protection module 300 is connected to the output end of the main control chip 500. The main control chip 500 can send a level signal to the failure protection module 300 to control the opening or closing of the failure protection module 300. The output end of the failure protection module 300 is connected to the control end of the charge and discharge MOS tube 200. The charge and discharge MOS tube 200 can be turned on and off according to the opening or closing of the failure module. When the charge and discharge current exceeds the maximum current of the battery cell, the main control chip 500 can control the failure protection module 300 to open, so as to directly close the charge and discharge MOS tube 200 to cut off the charge and discharge circuit, thereby protecting the safety of the battery cell.

[0029] Further, refer to Figure 1A sampling resistor R1 is provided at the negative ground terminal of the output module 600, and the input terminal of the main control chip 500 is respectively connected to the two ends of the sampling resistor R1 for collecting the output voltage. The main control chip 500 obtains the current charge and discharge state by collecting the output voltage. When the current charge and discharge state is abnormal, the failure protection module 300 is controlled to be turned on to turn off the charge and discharge MOS tube 200 and cut off the charge and discharge circuit, thereby protecting the safety of the battery cell.

[0030] In this embodiment, by setting a sampling resistor R1 on the negative electrode of the system output end, and connecting the input end of the system main control chip to the two ends of the sampling resistor respectively, the system can timely collect the voltage of the output end; by setting a failure protection module, and connecting the output end of the failure protection module to the control end of the charge and discharge MOS tube, and connecting the input end of the failure protection module to the control end of the main control chip, when the system main control chip detects that the voltage at the output end is abnormal, it can generate a corresponding level signal to the failure protection module to control the failure protection module to start, thereby controlling the charge and discharge MOS tube to be cut off. This control process does not require the help of a lithium battery protection chip, and realizes the function of timely cutting off the charge and discharge MOS tube to protect the battery cell when the output voltage is abnormal even when the system protection mechanism fails.

[0031] In one embodiment, reference Figure 1 and Figure 2 The failure protection module 300 includes a first MOS transistor Q5 and a second MOS transistor Q6. The drain of the first MOS transistor Q5 and the drain of the second MOS transistor Q6 are both connected to the charge and discharge MOS transistor 200. The gate of the first MOS transistor Q5 and the gate of the second MOS transistor Q6 are both connected to the main control chip 500. The source of the first MOS transistor Q5 and the source of the second MOS transistor Q6 are both grounded.

[0032] Specifically, refer to Figure 1 and Figure 2 The failure protection module 300 includes a first MOS tube Q5, the gate of the first MOS tube Q5 is connected to the output pin of the main control chip 500 to obtain a control instruction and turn on or off, the drain of the first MOS tube Q5 is connected to one of the charging control gate and the discharging control gate in the charging and discharging MOS tube 200 to control the charging control gate or the discharging control gate in the charging and discharging MOS tube 200 to be turned off, and the source of the first MOS tube Q5 is grounded.

[0033] Further, refer to Figure 1 and Figure 2The failure protection module 300 includes a second MOS tube Q6, the gate of the second MOS tube Q6 is connected to the output pin of the main control chip 500 to obtain the control instruction and turn on or off, the drain of the second MOS tube Q6 is connected to the other of the charging control gate and the discharging control gate in the charging and discharging MOS tube 200 to control the charging control gate or the discharging control gate in the charging and discharging MOS tube 200 to be turned off, and the source of the second MOS tube Q6 is grounded.

[0034] Among them, reference Figure 1 and Figure 2 When the system is short-circuited, the DC-DC has failed, the current passes through the port and the sampling resistor R1 and then is grounded. The main control chip 500 collects the voltage across the sampling resistor R1 to obtain the output voltage. When the main control chip 500 determines that the current system is short-circuited according to the output voltage, it outputs a high-level signal to the gates of the first MOS tube Q5 and the second MOS tube Q6, so that the first MOS tube Q5 and the second MOS tube Q6 are both turned on. At this time, the charging control gate and the discharging control gate in the charging and discharging MOS tube 200 are both low levels, the charging and discharging MOS tube 200 is turned off, and the charging and discharging loop is cut off to prevent the continuous charging and discharging after the system is short-circuited from causing damage to the battery cell.

[0035] In one embodiment, reference Figure 3 and Figure 4 The main control chip 500 is provided with a first sampling pin ISMP and a second sampling pin ISMN, the first sampling pin ISMP and the second sampling pin ISMN are respectively connected to the two ends of the sampling resistor R1, and a first protection resistor R42 is provided between the first sampling pin ISMP and the sampling resistor R1, and a second protection resistor R45 is provided between the second sampling pin ISMN and the sampling resistor R1, and a first pull-up resistor R43 and a second pull-up resistor R46 are also respectively connected to the first sampling pin ISMP and the second sampling pin ISMN of the main control chip 500.

[0036] Specifically, refer to Figure 3 and Figure 4, one end of the sampling resistor R1 is connected to the output module 600, the other end of the sampling resistor R1 is grounded, one end of the first protection resistor R42 is connected to one end of the sampling resistor R1, the other end of the first protection resistor R42 is connected to one end of the first pull-up resistor R43, the other end of the first pull-up resistor R43 is connected to the driving power supply, one end of the second protection resistor R45 is connected to the other end of the sampling resistor R1, the other end of the second protection resistor R45 is connected to one end of the second pull-up resistor R46, the other end of the second pull-up resistor R46 is connected to the driving power supply, the first sampling pin ISMP of the main control chip 500 is connected between the first protection resistor R42 and the first pull-up resistor R43, and the second sampling pin ISMN of the main control chip 500 is connected between the second protection resistor R45 and the second pull-up resistor R46 to collect the voltage across the sampling resistor R1 in real time.

[0037] In one embodiment, referring to Figure 5 , a third protection resistor R8 is provided between the output end of the DC-DC module 400 and the output module 600.

[0038] Specifically, referring to Figure 5 , the lithium battery protection system further includes a current regulation module. The input end of the current regulation module is connected to the main control chip 500 to obtain the cell NTC temperature. The output end of the current regulation module is respectively connected to both ends of the third protection resistor R8. The current regulation module is used to adjust and control the input and output current according to the cell NTC temperature to ensure the safety of the cell.

[0039] Among them, referring to Figure 5 , the current regulation module includes a first regulation circuit and a second regulation circuit. The first regulation circuit includes a first voltage reference chip U4. The reference terminal and the positive terminal of the first voltage reference chip U4 are both connected to the main control chip 500. The negative terminal of the first voltage reference chip U4 is connected to one end of the third protection resistor R8. The first regulation circuit further includes a resistor R25, a resistor R26, and a capacitor C23. One end of the resistor R25 is connected to the reference terminal of the first voltage reference chip U4, the other end of the resistor R25 is connected to the main control chip 500. One end of the capacitor C23 is connected between the resistor R25 and the reference terminal of the first voltage reference chip U4, and the other end of the capacitor C23 is grounded. The resistor R26 is connected in parallel with the capacitor C23. The first regulation circuit further includes a resistor R28, a resistor R27, and a capacitor C24. One end of the resistor R28 is connected to the positive terminal of the first voltage reference chip U4, the other end of the resistor R28 is connected to the main control chip 500. One end of the capacitor C24 is connected between the resistor R28 and the positive terminal of the first voltage reference chip U4, and the other end of the capacitor C24 is grounded. The resistor R27 is connected in parallel with the capacitor C24.

[0040] Furthermore, referring to Figure 5The second regulating band circuit includes a second voltage reference chip U5, the reference end and the positive electrode of the second voltage reference chip U5 are connected to the main control chip 500, and the negative electrode of the second voltage reference chip U5 is connected to the other end of the third protection resistor R8; the first regulating circuit also includes a resistor R29, a resistor R30 and a capacitor C25, one end of the resistor R29 is connected to the reference end of the second voltage reference chip U5, the other end of the resistor R29 is connected to the main control chip 500, and one end of the capacitor C25 is connected between the resistor R29 and the second voltage reference chip U5. The reference end of the reference chip U5, the other end of the capacitor C25 is grounded, and the resistor R30 is connected in parallel to the capacitor C25; the second adjustment circuit also includes a resistor R32, a resistor R31 and a capacitor C26, one end of the resistor R32 is connected to the positive terminal of the second voltage reference chip U5, the other end of the resistor R32 is connected to the main control chip 500, one end of the capacitor C26 is connected between the resistor R32 and the positive terminal of the first voltage reference chip U4, the other end of the capacitor C26 is grounded, and the resistor R31 is connected in parallel to the capacitor C26.

[0041] In one embodiment, reference Figure 6 The lithium battery protection system also includes a display module 700, which is connected to the main control chip 500 and includes at least one LED display light.

[0042] The utility model also provides a specific embodiment of a mobile power supply.

[0043] A mobile power source comprises the lithium battery protection system as described above, and also comprises a battery pack, wherein the battery pack is connected to a voltage input terminal of a DC-DC module.

[0044] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present utility model rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present utility model.

Claims

1. A lithium battery protection system, characterized in that: include: Battery protection chip, charging and discharging MOS tube, failure protection module, DC-DC module, main control chip and output module; The voltage input end of the DC-DC module is connected to the battery pack, the voltage output end of the DC-DC module is connected to the output module, the battery protection chip and the charge and discharge MOS tube are both arranged between the battery pack and the DC-DC module, the control end of the failure protection module is connected to the output end of the main control chip, the output end of the failure protection module is connected to the control end of the charge and discharge MOS tube, the negative grounding end of the output module is provided with a sampling resistor, and the main control chip is respectively connected to both ends of the sampling resistor.

2. The lithium battery protection system according to claim 1, characterized in that: The failure protection module includes a first MOS tube and a second MOS tube, the drain of the first MOS tube and the drain of the second MOS tube are both connected to the charging and discharging MOS tube, the gate of the first MOS tube and the gate of the second MOS tube are both connected to the main control chip, and the source of the first MOS tube and the source of the second MOS tube are both grounded.

3. The lithium battery protection system according to claim 1, characterized in that: The main control chip is provided with a first sampling pin and a second sampling pin, the first sampling pin and the second sampling pin are respectively connected to two ends of the sampling resistor, and a first protection resistor is provided between the first sampling pin and the sampling resistor, and a second protection resistor is provided between the second sampling pin and the sampling resistor.

4. The lithium battery protection system according to claim 3, characterized in that: The first sampling pin and the second sampling pin of the main control chip are respectively connected to a first pull-up resistor and a second pull-up resistor.

5. The lithium battery protection system according to claim 1, characterized in that: A third protection resistor is arranged between the output end of the DC-DC module and the output module.

6. The lithium battery protection system according to claim 5, characterized in that: It also includes a current regulating module, the input end of the current regulating module is connected to the main control chip, and the output end of the current regulating module is respectively connected to the two ends of the third protection resistor.

7. The lithium battery protection system according to claim 6, characterized in that: The current regulating module comprises a first voltage reference chip, a reference terminal and a positive electrode of the first voltage reference chip are both connected to the main control chip, and a negative electrode of the first voltage reference chip is connected to one end of the third protection resistor.

8. The lithium battery protection system according to claim 6, characterized in that: The current regulating module also includes a second voltage reference chip, the reference end and the positive electrode of the second voltage reference chip are both connected to the main control chip, and the negative electrode of the second voltage reference chip is connected to the other end of the third protection resistor.

9. The lithium battery protection system according to claim 1, characterized in that: It also includes a display module, which is connected to the main control chip and includes at least one LED display light.

10. A mobile power source, characterized in that: It comprises a lithium battery protection system as described in any one of claims 1 to 9, and also comprises a battery pack, wherein the battery pack is connected to the voltage input terminal of the DC-DC module.

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