A battery management device and an electrical device

Abstract

The present invention is applicable to the field of battery management technology, and provides a battery management device and an electrical device. The battery management device includes: a battery unit, the battery unit is connected to an external load unit; a protection unit connected to the battery unit; a charging unit and a discharging unit connected to the protection unit, the charging unit and the discharging unit are connected to each other; a switch unit connected to the discharging unit; a driving unit connected to the switch unit; when the driving unit detects that the voltage of the load unit rises to a set value, the driving unit drives the switch unit to turn on, and the switch unit controls the discharging unit to turn off, and by directly detecting the voltage of the load unit, the charging and discharging mode of the battery unit can be switched by utilizing the change in voltage. When the driving unit detects that the voltage of the load unit rises, the discharge protection is triggered, the discharge unit is quickly turned off, and short-circuit protection is achieved with fewer MOS tubes, and the cost is very low.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery management, and in particular relates to a battery management device and an electrical device. Background Art

[0002] In the prior art, the battery protection circuit mostly uses a protection IC (or a single-chip microcomputer) and a driving circuit connected to the protection IC, which can detect a variety of fault conditions from simple faults (overvoltage only) to advanced faults (detecting more faults), such as overvoltage, undervoltage, discharge overcurrent and short circuit. When the battery is overcharged, the charging state must be cut off to prevent the internal pressure from rising due to temperature rise. When the protection IC detects overcharging, the power MOSFET of the overcharge detection cuts it off and cuts off the charging. As the use time increases, the voltage of the charged lithium-ion battery will gradually decrease, and finally fall below the standard value of the specification, at which time it needs to be recharged.

[0003] To prevent over-discharge, the protection IC must detect the battery voltage. Once it reaches below the over-discharge detection voltage, the power MOSFET on the discharge side must be cut off to stop the discharge. However, at this time, the battery itself still has natural discharge and the protection IC consumes current, so it is necessary to minimize the current consumed by the protection IC. When a short circuit occurs due to unknown reasons, the discharge must be stopped immediately. However, since the driving current of the protection IC is relatively small, the MOS tube is usually turned off slowly. Summary of the invention

[0004] The present invention provides a battery management device, aiming to solve the problem of slow shut-off speed of MOS tubes during battery protection.

[0005] The present invention is implemented in this way: a battery management device comprises:

[0006] A battery unit, wherein the battery unit is connected to an external load unit;

[0007] A protection unit connected to the battery unit;

[0008] A charging unit and a discharging unit connected to the protection unit, wherein the charging unit and the discharging unit are connected to each other;

[0009] a switch unit connected to the discharge unit;

[0010] a driving unit connected to the switch unit;

[0011] When the driving unit detects that the voltage of the load unit increases to a set value, the driving unit drives the switch unit to turn on, and the switch unit controls the discharge unit to turn off.

[0012] Furthermore, the driving unit includes a first resistor, one end of the first resistor is connected to the load unit, and the other end of the first resistor is connected to the switch unit.

[0013] Furthermore, the driving unit also includes a second resistor, a first MOS tube and a driving module, the resistance of the first resistor is greater than the resistance of the second resistor, the gate of the first MOS tube is connected to the driving module, the drain of the first MOS tube is respectively connected to one end of the first resistor and the load unit, the source of the first MOS tube is connected to one end of the second resistor, and the other end of the first resistor and the other end of the second resistor are both connected to the switching unit.

[0014] Furthermore, the driving module includes a second MOS tube, the drain of the second MOS tube is respectively connected to the power supply end and the gate of the first MOS tube, the source of the second MOS tube is connected to the ground end, and the gate of the second MOS tube is connected to the load unit.

[0015] Furthermore, the switching unit includes a transistor and a third resistor, the base of the transistor is respectively connected to the first resistor, the second resistor and one end of the third resistor, the collector of the transistor is respectively connected to the protection unit and the discharge unit, and the emitter of the transistor is respectively connected to the other end of the third resistor and the discharge unit.

[0016] Furthermore, the driving module also includes a fourth resistor, a fifth resistor, a sixth resistor and a capacitor, one end of the fourth resistor is connected to the drain of the second MOS tube, the other end of the fourth resistor is connected to the power supply end, one end of the fifth resistor is connected to the source of the second MOS tube, the other end of the fifth resistor is connected to the gate of the second MOS tube, the sixth resistor is connected to the gate of the second MOS tube, and the other end of the sixth resistor is connected to the load unit.

[0017] Furthermore, the discharge unit is a third MOS tube, the gate of the third MOS tube is respectively connected to the collector of the transistor and the protection unit, the source of the third MOS tube is connected to the emitter of the transistor and the ground terminal, and the drain of the third MOS tube is connected to the charging unit.

[0018] Furthermore, the charging unit is a fourth MOS tube, a gate of the fourth MOS tube is connected to the protection unit, a source of the fourth MOS tube is connected to the load unit, and a drain of the fourth MOS tube is connected to the drain of the third MOS tube.

[0019] Furthermore, the battery management device further includes a shunt unit, and two ends of the shunt unit are respectively connected to the protection unit.

[0020] An embodiment of the present invention further provides an electrical device, which includes the battery management device.

[0021] In the battery management device provided by the present invention, when the driving unit detects that the voltage of the load unit rises, the present invention can realize switching the charge and discharge mode of the battery unit by using the voltage change by directly detecting the voltage of the load unit. When the driving unit detects that the voltage of the load unit rises, the discharge protection is triggered, and the discharge unit is quickly turned off, so that short circuit protection is realized with fewer MOS tubes and the cost is very low. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a block diagram of a battery management device provided by an embodiment of the present invention;

[0023] Figure 2 The present invention provides a circuit diagram of a battery management device. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] The battery management device provided by the present invention comprises: a battery cell, a protection unit, a charging unit and a discharging unit, a switch unit, and a driving unit; when the driving unit detects that the voltage of the load unit increases, the driving unit drives the switch unit to turn on, and the switch unit controls the discharging unit to turn off. The present invention can switch the charging and discharging mode of the battery cell by utilizing the change of voltage by directly detecting the voltage of the load unit. When the driving unit detects that the voltage of the load unit increases, the discharge protection is triggered and the discharging unit is quickly turned off.

[0026] Embodiment 1

[0027] This embodiment provides a battery management device, such as Figure 1 As shown, including:

[0028] A battery unit 1, the battery unit 1 is connected to an external load unit 2;

[0029] A protection unit 3 connected to the battery unit 1;

[0030] A charging unit 4 and a discharging unit 5 connected to the protection unit 3, wherein the charging unit 4 and the discharging unit 5 are connected to each other;

[0031] A switch unit 6 connected to the discharge unit 5;

[0032] A driving unit 7 connected to the switch unit 6;

[0033] When the driving unit 7 detects that the voltage of the load unit 2 increases to a set value, the driving unit 7 drives the switch unit 6 to turn on, and the switch unit 6 controls the discharge unit 5 to turn off.

[0034] The working principle of the above battery management device is:

[0035] During the discharge process of the battery cell 1, the switch unit 6 does not work, the discharge unit 5 is in the open state, and the drive unit 7 detects the voltage of the load unit 2 in real time. When the drive unit 7 detects that the voltage of the load unit 2 rises to a certain set value (the driving voltage of the drive unit 7), the discharge protection is triggered, and the drive unit 7 drives the switch unit 6 to turn on. The switch unit 6 controls the discharge unit 5 to gradually change from the open state to the disconnected state. Specifically, during the process of disconnecting the discharge unit 5, the voltage passing through the discharge unit 5 or the charging unit 4 gradually increases after passing through the load unit 2. When it rises to the driving voltage of the drive unit 7, the drive unit 7 quickly turns off the discharge unit 5.

[0036] In this embodiment, the protection unit 3 uses a protection IC that can be purchased on the market. Under normal circumstances, there is no voltage at the negative terminal P- / C- of the load unit 2. Since undervoltage, temperature, overcurrent, short circuit, etc. are prone to occur during the discharge process of the battery unit 2, this will cause the voltage of the negative terminal P- / C- of the load unit 2 to gradually increase. Therefore, by directly detecting the voltage of the load unit 2, the charge and discharge mode of the battery unit 1 can be switched by using the change in voltage. When the driving unit 7 detects that the voltage of the load unit 2 increases, the discharge protection is triggered, and the discharge unit 5 is quickly turned off, and short-circuit protection is achieved with fewer MOS tubes, and the cost is very low. In addition, in the prior art, the current of the shunt resistor is detected to determine whether there is a short circuit. If so, the protection IC controls the discharge MOS tube to disconnect. This protection method has a slow response speed for situations where protection needs to be started, and the current of the shunt resistor cannot accurately reflect the short circuit situation. In this embodiment, the voltage of the load unit 2 is directly detected to see if the induced voltage rises. If so, the driving unit 7 drives the switch unit 6 to turn on, and then the switch unit 6 controls the discharge unit 5 to quickly disconnect. The voltage of the load unit 2 directly and accurately reflects the short circuit condition of the circuit, thus avoiding misjudgment.

[0037] Embodiment 2

[0038] This embodiment provides a battery management device, such as Figure 2As shown, the driving unit 7 includes a first resistor R4, one end of the first resistor R4 is connected to the load unit 2, and the other end of the first resistor R4 is connected to the switch unit 6. If undervoltage, temperature, overcurrent, short circuit, etc. occur during the discharge process of the battery unit 2, the voltage of the negative terminal P- / C- of the load unit 2 gradually increases, and the voltage flowing through the first resistor R4 also gradually increases, so that the discharge protection is triggered and the discharge unit 5 is quickly turned off. At this time, only one resistor is needed to realize the corresponding function of the driving unit, and the device structure is very simple.

[0039] The driving unit 7 further includes a second resistor R3, a first MOS tube Q3 and a driving module 7-1. The resistance of the first resistor R4 is greater than the resistance of the second resistor R3. The gate of the first MOS tube is connected to the driving module 7-1. The drain of the first MOS tube Q3 is respectively connected to one end of the first resistor R4 and the load unit 2. The source of the first MOS tube Q3 is connected to one end of the second resistor R3. The other end of the first resistor R4 and the other end of the second resistor R4 are both connected to the switch unit 6.

[0040] The working principle of the first MOS tube Q3 is as follows: after a voltage of correct polarity and magnitude is applied between the source and drain of the first MOS tube Q3, a control voltage is applied between the gate and source of the first MOS tube Q3, which will generate a current of corresponding magnitude flowing from the source to the drain. If the signal voltage reaches a certain level, the first MOS tube Q3 can be instantly saturated and become a switch.

[0041] In this embodiment, if the negative terminal P- / C- of the load unit 2 is at a low level, the driving module 7-1 drives the first MOS tube Q3 to a high level, the first MOS tube Q3 is turned on, and the second resistor R3 with a smaller resistance is turned on, and the signal flows through the second resistor R3, thereby increasing the driving capability of the driving unit 7 (making the discharge unit 5 turn off faster). If the negative terminal P- / C- of the load unit 2 is at a high level, the driving module 7-1 drives the first MOS tube Q3 to a low level, and the first MOS tube Q3 is turned off, then the first resistor R4 with a larger resistance is turned on, and the signal flows through the first resistor R4. In this process, the current becomes smaller, thereby reducing power consumption. The driving module 7-1 here is not limited, and it only needs to be able to achieve the level conversion of driving the first MOS tube Q3.

[0042] Embodiment 3

[0043] This embodiment provides a battery management device, such as Figure 2 As shown, the driving module 7 - 1 includes a second MOS transistor Q4 , the drain of the second MOS transistor Q4 is respectively connected to the power supply end and the gate of the first MOS transistor Q3 , the source of the second MOS transistor Q4 is connected to the ground end, and the gate of the second MOS transistor Q4 is connected to the load unit 2 .

[0044] The driving module 7-1 further includes a fourth resistor R7, a fifth resistor R6, a sixth resistor R5 and a capacitor C1, one end of the fourth resistor R7 is connected to the drain of the second MOS tube Q4, the other end of the fourth resistor R7 is connected to the power supply end, one end of the fifth resistor R6 is connected to the source of the second MOS tube Q4, the other end of the fifth resistor R6 is connected to the gate of the second MOS tube Q4, the sixth resistor R5 is connected to the gate of the second MOS tube Q4, and the other end of the sixth resistor R5 is connected to the load unit 2.

[0045] In this embodiment, when the battery unit 1 is short-circuited, the voltage of the negative terminal P- / C- of the load unit 2 gradually increases, providing voltage for the second MOS tube Q4, so that the drain, gate and source of the second MOS tube Q4 are connected and grounded. Since the voltage does not flow through the first MOS tube Q3, the first MOS tube Q3 is in a disconnected state, and the discharge unit 5 is turned off to achieve short-circuit protection. By selecting the sixth resistor R5 and the capacitor C1 with different values, the delay time required for detection can be adjusted. When the voltage of the negative terminal P- / C- of the load unit 2 reaches a certain value, by adjusting the resistance values ​​of the fifth resistor R6 and the sixth resistor R5, the second MOS tube Q4 can be closed, thereby controlling the closing and opening of the first MOS tube Q3.

[0046] Embodiment 4

[0047] This embodiment provides a battery management device, such as Figure 2 As shown, the switch unit 6 includes a transistor Q5 and a third resistor R2, the base of the transistor Q5 is respectively connected to the first resistor R4, the second resistor R3 and one end of the third resistor R2, the collector of the transistor Q5 is respectively connected to the protection unit 3 and the discharge unit 5, and the emitter of the transistor Q5 is respectively connected to the other end of the third resistor R2 and the discharge unit 5.

[0048] In this embodiment, the third resistor R2 is used for voltage division. When the battery unit 1 is discharged normally, there is no voltage at the negative terminal P- / C- of the load unit 2. VCC provides voltage to the first MOS transistor Q3, so that the drain, gate and source of the first MOS transistor Q3 are connected, and the voltage flows through the first MOS transistor Q3 to the discharge unit 5 (the third MOS transistor Q1), thereby realizing the normal discharge of the battery unit 1. At this time, the transistor Q5 is not turned on. When the battery unit 1 is short-circuited, the voltage at the negative terminal P- / C- of the load unit 2 increases, and provides voltage to the second MOS transistor Q4, so that the drain, gate and source of the second MOS transistor Q4 are connected and then grounded. Since the voltage does not flow through the first MOS transistor Q3, the first MOS transistor Q3 is in a disconnected state, and the voltage directly flows to the transistor Q5 through the first resistor R4, so that the transistor Q5 is turned on, and the voltage returns to the battery unit 1, realizing short-circuit protection.

[0049] Embodiment 5

[0050] This embodiment provides a battery management device, such as Figure 2 As shown, the discharge unit 5 is a third MOS tube Q1, the gate of the third MOS tube Q1 is respectively connected to the collector of the transistor Q5 and the protection unit 3, the source of the third MOS tube Q1 is connected to the emitter of the transistor Q5 and the ground terminal, and the drain of the third MOS tube Q1 is connected to the charging unit 4.

[0051] The charging unit 4 is a fourth MOS tube Q2 , a gate of the fourth MOS tube Q2 is connected to the protection unit 3 , a source of the fourth MOS tube Q2 is connected to the load unit 2 , and a drain of the fourth MOS tube Q2 is connected to the drain of the third MOS tube Q1 .

[0052] In this embodiment, the third MOS tube Q1 is turned on when the battery cell 1 is discharged normally, and is turned off when the battery cell 1 is short-circuited. The fourth MOS tube Q2 is turned off when the battery cell 1 is charged, and is turned on when the battery cell 1 is short-circuited.

[0053] Embodiment 6

[0054] This embodiment provides a battery management device, such as Figure 2 As shown, the battery management device further includes a shunt unit 8 , and two ends of the shunt unit 8 are respectively connected to the protection unit 3 .

[0055] In this embodiment, the current dividing unit 8 is a seventh resistor R1, which is used for current dividing when a large current passes through.

[0056] Specifically, when the battery cell 1 is short-circuited, a large current is generated at the negative terminal P- / C- of the load unit 2, and the impedance between the negative terminal P- / C- of the load unit 2 and the negative terminal B- of the battery cell 1*current=the voltage at the negative terminal P- / C- of the load unit 2, wherein the impedance between the negative terminal P- / C- of the load unit 2 and the negative terminal B- of the battery cell 1 is the sum of the internal resistance of the third MOS tube Q1, the internal resistance of the fourth MOS tube Q2, and the impedance of the seventh resistor R1 (shunt unit 8). When the battery cell 1 is discharged normally, the impedance between the negative terminal P- / C- of the load unit 2 and the negative terminal B- of the battery cell 1*current=the voltage of the negative terminal P- / C- of the load unit 2, wherein the impedance between the negative terminal P- / C- of the load unit 2 and the negative terminal B- of the battery cell 1 is the sum of the internal resistance of the third MOS tube Q1 and the impedance of the seventh resistor R1 (shunt unit 8). Since the loop impedance of the battery cell 1 is small during normal discharge, the shutdown speed is very fast, which plays a good role in short-circuit protection. When the short-circuit protection of the battery cell is completed, it will switch to a high-impedance loop, so that the circuit is in a low power consumption state, thereby reducing power consumption.

[0057] Embodiment 7

[0058] This embodiment further provides an electrical device, which includes the above-mentioned battery management device.

[0059] In this embodiment, since the battery management device is applied in the electrical device, energy consumption is reduced, and discharge protection can be quickly responded to, thereby preventing the electrical device from being damaged due to short circuit and the like.

[0060] The embodiment of the present invention provides a battery management device and an electrical device. The battery management device can switch the charge and discharge mode of the battery unit by using the change of voltage by directly detecting the voltage of the load unit. When the driving unit detects that the voltage of the load unit increases, the discharge protection is triggered and the discharge unit is quickly turned off. Specifically, if the negative end of the load unit is at a low level, the driving module drives the first MOS tube to a high level, and the second resistor with a smaller resistance is turned on, increasing the driving ability of the driving unit, so that the discharge unit is turned off faster. If the negative end of the load unit is at a high level, the driving module drives the first MOS tube to a low level, the first MOS tube is turned off, and the first resistor with a larger resistance is turned on. In this process, the current becomes smaller, thereby reducing power consumption. The third MOS tube is turned on when the battery unit is discharged normally, and is turned off when the battery unit is short-circuited. The fourth MOS tube is turned off when the battery unit is charged, and is turned on when the battery unit is short-circuited. The application of the above-mentioned battery management device in the electrical device can reduce energy consumption, and can quickly respond to discharge protection to avoid damage to the electrical appliance due to short circuits and the like.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A battery management device, characterized in that: The battery management device comprises: A battery unit, wherein the battery unit is connected to an external load unit; A protection unit connected to the battery unit; A charging unit and a discharging unit connected to the protection unit, wherein the charging unit and the discharging unit are connected to each other; a switch unit connected to the discharge unit; a driving unit connected to the switch unit; When the driving unit detects that the voltage of the load unit increases to a set value, the driving unit drives the switch unit to turn on, and the switch unit controls the discharge unit to turn off; The driving unit comprises a first resistor, one end of the first resistor is connected to the load unit, and the other end of the first resistor is connected to the switch unit; The driving unit further includes a second resistor, a first MOS transistor and a driving module, the resistance of the first resistor is greater than the resistance of the second resistor, the gate of the first MOS transistor is connected to the driving module, the drain of the first MOS transistor is respectively connected to one end of the first resistor and the load unit, the source of the first MOS transistor is connected to one end of the second resistor, and the other end of the first resistor and the other end of the second resistor are both connected to the switch unit; The switching unit includes a transistor and a third resistor, the base of the transistor is respectively connected to the first resistor, the second resistor and one end of the third resistor, the collector of the transistor is respectively connected to the protection unit and the discharge unit, and the emitter of the transistor is respectively connected to the other end of the third resistor and the discharge unit.

2. The battery management device according to claim 1, characterized in that: The driving module includes a second MOS tube, the drain of the second MOS tube is respectively connected to the power supply end and the gate of the first MOS tube, the source of the second MOS tube is connected to the ground end, and the gate of the second MOS tube is connected to the load unit.

3. The battery management device according to claim 2, characterized in that: The driving module also includes a fourth resistor, a fifth resistor, a sixth resistor and a capacitor, one end of the fourth resistor is connected to the drain of the second MOS tube, the other end of the fourth resistor is connected to the power supply end, one end of the fifth resistor is connected to the source of the second MOS tube, the other end of the fifth resistor is connected to the gate of the second MOS tube, the sixth resistor is connected to the gate of the second MOS tube, and the other end of the sixth resistor is connected to the load unit.

4. The battery management device according to claim 1, characterized in that: The discharge unit is a third MOS tube, the gate of the third MOS tube is respectively connected to the collector of the triode and the protection unit, the source of the third MOS tube is connected to the emitter of the triode and the ground terminal, and the drain of the third MOS tube is connected to the charging unit.

5. The battery management device according to claim 4, characterized in that: The charging unit is a fourth MOS tube, a gate of the fourth MOS tube is connected to the protection unit, a source of the fourth MOS tube is connected to the load unit, and a drain of the fourth MOS tube is connected to the drain of the third MOS tube.

6. The battery management device according to claim 1, characterized in that: The battery management device further comprises a shunt unit, and two ends of the shunt unit are respectively connected to the protection unit.

7. An electrical device, characterized in that: The electrical device comprises the battery management device as claimed in any one of claims 1 to 6.

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