Battery protection circuit, battery and electronic device

Abstract

A battery protection circuit for protecting a battery, the battery protection circuit comprising a first protection circuit and a second protection circuit; the battery protection circuit comprises: a current detection resistor, the first protection circuit and the second protection circuit are respectively electrically connected to both ends of the current detection resistor; a first capacitor, the first capacitor is electrically connected to the first protection circuit, and both ends of the first capacitor are respectively electrically connected to both ends of the current detection resistor; a first resistor, the first resistor is connected in series between the current detection resistor and the first capacitor, and the resistance value of the first resistor is much larger than the resistance value of the current detection resistor. The application also provides a battery and an electronic device, which can avoid the failure of the secondary protection circuit caused by the short circuit of the capacitor.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery protection circuit, a battery, and an electronic device. Background Technology

[0002] Currently, lithium-ion batteries have advantages such as high energy density, high power density, high cycle life, and long storage time. They have broad application prospects in large and medium-sized electric equipment such as electric vehicles and energy storage facilities. Therefore, lithium-ion batteries have become a key to solving global problems such as the energy crisis and environmental pollution.

[0003] With the increasing pursuit of higher performance in electric devices, people have higher and higher requirements for the safety and reliability of lithium-ion batteries. Currently, lithium-ion batteries mostly employ a two-stage protection circuit, in which a capacitor is connected in series between the overcurrent protection terminal and the ground terminal of each stage of the protection circuit. However, when any one of these capacitors short-circuits, the function of each stage of the two-stage protection circuit will fail. Summary of the Invention

[0004] In view of this, it is necessary to provide a battery protection circuit, battery, and electronic device that can prevent the failure of the secondary protection circuit caused by capacitor short circuit.

[0005] One embodiment of this application provides a battery protection circuit for protecting a battery. The battery protection circuit includes a first protection circuit and a second protection circuit. The battery protection circuit includes:

[0006] A current-detecting resistor is provided, and both the first protection circuit and the second protection circuit are electrically connected to the two ends of the current-detecting resistor.

[0007] The first capacitor is electrically connected to the first protection circuit, and the two ends of the first capacitor are respectively electrically connected to the two ends of the current detection resistor.

[0008] A first resistor is connected in series between the current-detecting resistor and the first capacitor, and the resistance value of the first resistor is much larger than the resistance value of the current-detecting resistor.

[0009] According to some embodiments of this application, the resistance value of the first resistor is at least 10 times the resistance value of the current sensing resistor.

[0010] According to some embodiments of this application, the battery protection circuit further includes:

[0011] The second capacitor is electrically connected to the second protection circuit, and the two ends of the second capacitor are electrically connected to the two ends of the current detection resistor.

[0012] A second resistor is connected in series between the current-detecting resistor and the second capacitor, and the resistance value of the second resistor is much larger than the resistance value of the current-detecting resistor.

[0013] According to some embodiments of this application, the resistance value of the second resistor is at least 10 times the resistance value of the current sensing resistor.

[0014] According to some embodiments of this application, the first protection circuit includes a first control chip and a first switch module controlled by the first control chip; the first switch module is used to turn on or off the electrical connection between the input / output terminal of the battery protection circuit and the battery electrode;

[0015] One end of the current sensing resistor is electrically connected to the ground terminal of the first control chip, and the other end of the current sensing resistor is electrically connected to the overcurrent detection terminal of the first control chip.

[0016] According to some embodiments of this application, the other end of the current sensing resistor is electrically connected to the overcurrent detection terminal of the first control chip through the first resistor.

[0017] According to some embodiments of this application, the second protection circuit includes a second control chip and a second switch module controlled by the second control chip; the second switch module is used to turn on or off the electrical connection between the input / output terminal of the battery protection circuit and the battery electrode;

[0018] One end of the current sensing resistor is electrically connected to the ground terminal of the second control chip, and the other end of the current sensing resistor is electrically connected to the overcurrent detection terminal of the second control chip.

[0019] According to some embodiments of this application, the other end of the current sensing resistor is electrically connected to the overcurrent detection terminal of the second control chip through the second resistor.

[0020] One embodiment of this application provides a battery that utilizes the battery protection circuit described in any of the preceding claims.

[0021] One embodiment of this application provides an electronic device that uses a battery protection circuit as described in any of the preceding claims.

[0022] The battery protection circuit, battery, and electronic device provided in this application embodiment use a resistor connected in series between the current detection resistor and the capacitor, and the resistance value of the resistor is much larger than the resistance value of the current detection resistor, so as to avoid the failure of the secondary protection circuit caused by the capacitor short circuit. Attached Figure Description

[0023] Figure 1This is a circuit diagram of a battery protection circuit according to an embodiment of this application.

[0024] Figure 2 for Figure 1 The circuit diagram shown is for the battery protection circuit after the first capacitor fails due to a short circuit.

[0025] Figure 3 for Figure 1 The circuit diagram shown is for the battery protection circuit after the second capacitor fails due to a short circuit.

[0026] Figure 4 This is a block diagram of a battery according to an embodiment of this application.

[0027] Figure 5 This is a block diagram of an electronic device according to an embodiment of this application.

[0028] Explanation of main component symbols

[0029] Battery protection circuit 1

[0030] First protection circuit 10

[0031] Second protection circuit 20

[0032] Current sensing resistor 30

[0033] First capacitor 40

[0034] First resistor 50

[0035] Second capacitor 60

[0036] Second resistor 70

[0037] Input / output terminals 80

[0038] Battery electrode 90

[0039] First control chip 11

[0040] First switch module 12

[0041] Grounding terminal 111

[0042] Overcurrent detection terminal 112

[0043] Second control chip 21

[0044] Second switch module 22

[0045] Grounding terminal 211

[0046] Overcurrent detection terminal 212

[0047] Battery 2

[0048] Electronic device 3

[0049] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0050] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0051] Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] Please see Figure 1 This is a circuit diagram of a battery protection circuit according to an embodiment of this application. The battery protection circuit 1 is used to protect the battery. The battery protection circuit 1 includes a first protection circuit 10 and a second protection circuit 20. The battery protection circuit 1 also includes a current sensing resistor 30, a first capacitor 40, and a first resistor 50. The first protection circuit 10 and the second protection circuit 20 are both electrically connected to the two ends of the current sensing resistor 30. The first capacitor 40 is electrically connected to the first protection circuit 10, and the two ends of the first capacitor 40 are respectively electrically connected to the two ends of the current sensing resistor 30. The first resistor 50 is connected in series between the current sensing resistor 30 and the first capacitor 40, and the resistance value of the first resistor 50 is much larger than the resistance value of the current sensing resistor 30. In this embodiment, the resistance value of the first resistor 50 is at least 10 times the resistance value of the current sensing resistor 30, preferably 10-10000 times. The current sensing resistor 30 can be a milliohm or ohm level resistor, and the first resistor 50 can be an ohm level resistor.

[0053] In this embodiment, the battery protection circuit 1 further includes a second capacitor 60 and a second resistor 70. The second capacitor 60 is electrically connected to the second protection circuit 20, and its two ends are electrically connected to the two ends of the current sensing resistor 30. The second resistor 70 is connected in series between the current sensing resistor 30 and the second capacitor 60, and the resistance value of the second resistor 70 is much larger than that of the current sensing resistor 30. In this embodiment, the resistance value of the second resistor 70 is at least 10 times that of the current sensing resistor 30, preferably 10-10000 times. The current sensing resistor 30 can be a milliohm or ohm level resistor, and the second resistor 70 can be an ohm level resistor.

[0054] In this embodiment, the battery protection circuit 1 further includes an input / output terminal 80 and a battery electrode 90. The first protection circuit 10 includes a first control chip 11 and a first switch module 12. The first switch module 12 is controlled by the first control chip 11. The first switch module 12 is used to connect or disconnect the electrical connection between the input / output terminal 80 of the battery protection circuit 1 and the battery electrode 90. In this embodiment, one end of the current sensing resistor 30 is electrically connected to the ground terminal 111 of the first control chip 11, and the other end of the current sensing resistor 30 is electrically connected to the overcurrent detection terminal 112 of the first control chip 11. In this embodiment, the other end of the current sensing resistor 30 is electrically connected to the overcurrent detection terminal 112 of the first control chip 11 through the first resistor 50.

[0055] In this embodiment, the second protection circuit 20 includes a second control chip 21 and a second switch module 22. The second switch module 22 is controlled by the second control chip 21. The second switch module 22 is used to connect or disconnect the electrical connection between the input / output terminal 80 of the battery protection circuit 1 and the battery electrode 90. In this embodiment, one end of the current sensing resistor 30 is electrically connected to the ground terminal 211 of the second control chip 21, and the other end of the current sensing resistor 30 is electrically connected to the overcurrent detection terminal 212 of the second control chip 21. In this embodiment, the other end of the current sensing resistor 30 is electrically connected to the overcurrent detection terminal 212 of the second control chip 21 through the second resistor 70.

[0056] The first control chip 11 and the second control chip 21 also include other terminals, such as a power supply terminal, a charging control terminal, a discharging control terminal, and a voltage acquisition terminal. The power supply terminal, the charging control terminal, the discharging control terminal, and the voltage acquisition terminal are existing technologies and will not be described in detail here.

[0057] Please see Figure 2 , Figure 2This is a circuit diagram of the battery protection circuit after the first capacitor 40 fails due to a short circuit. When the first capacitor 40 fails due to a short circuit, the overcurrent detection terminal 112 of the first control chip 11 and the ground terminal 111 of the first control chip 11 are at the same potential. At this time, the overcurrent detection of the first control chip 11 fails, and the overcurrent protection of the first protection circuit 10 fails. Since a first resistor 50 is connected in series between the first capacitor 40 and the current detection resistor 30, the current detection resistor 30 will not be bypassed after the first capacitor 40 fails due to a short circuit, but will form a parallel relationship with the first resistor 50. At this time, the voltage between the overcurrent detection terminal 212 of the second control chip 21 and the ground terminal 211 of the second control chip 21 is the voltage across the parallel connection of the current detection resistor 30 and the first resistor 50. Since the resistance value of the first resistor 50 is at least 10 times that of the current-detecting resistor 30, and the resistance value of the current-detecting resistor 30 connected in parallel with the first resistor 50 is close to that of the current-detecting resistor 30, it can be considered as the resistance value of the current-detecting resistor 30. Therefore, the second control chip 21 can be considered as detecting the voltage across the current-detecting resistor 30. In this case, the second protection circuit 20 will not fail its overcurrent protection due to the short-circuit failure of the first capacitor 40. Thus, when the first capacitor 40 fails due to a short circuit, the overcurrent protection of the first protection circuit 10 fails, but the overcurrent protection of the second protection circuit 20 does not fail, and the battery protection circuit 1 can continue to protect the battery.

[0058] Please see Figure 3 , Figure 3This is a circuit diagram of the battery protection circuit after the second capacitor 60 fails due to a short circuit. When the second capacitor 60 fails due to a short circuit, the overcurrent detection terminal 212 of the second control chip 21 and the ground terminal 211 of the second control chip 21 are at the same potential. At this time, the overcurrent detection of the second control chip 21 fails, and the overcurrent protection of the second protection circuit 20 fails. Since a second resistor 70 is connected in series between the second capacitor 60 and the current detection resistor 30, the current detection resistor 30 will not be bypassed after the second capacitor 60 fails due to a short circuit, but will form a parallel relationship with the second resistor 70. At this time, the voltage between the overcurrent detection terminal 112 of the first control chip 11 and the ground terminal 111 of the first control chip 11 is the voltage across the parallel connection of the current detection resistor 30 and the second resistor 70. Since the resistance value of the second resistor 70 is at least 10 times that of the current-detecting resistor 30, and the resistance value of the current-detecting resistor 30 connected in parallel with the second resistor 70 is close to that of the current-detecting resistor 30, it can be considered as the resistance value of the current-detecting resistor 30. Therefore, the first control chip 11 can be considered as detecting the voltage across the current-detecting resistor 30. In this case, the first protection circuit 10 will not fail its overcurrent protection due to the short-circuit failure of the second capacitor 60. Thus, when the second capacitor 60 fails due to a short circuit, the overcurrent protection of the second protection circuit 20 fails, but the overcurrent protection of the first protection circuit 10 does not fail, and the battery protection circuit 1 can continue to protect the battery.

[0059] Please see Figure 4 The diagram shows a block illustration of the battery. The battery 2 is a rechargeable battery. For example, the battery 2 can be a lead-acid battery, nickel-cadmium battery, nickel-metal hydride battery, lithium-ion battery, lithium polymer battery, and lithium iron phosphate battery, etc. The battery 2 can be repeatedly charged using a rechargeable method. The battery 2 includes the battery protection circuit 1. The battery 2 utilizes the battery protection circuit 1. The battery 2 may also include other components, such as battery cells, which will not be described in detail here.

[0060] Please see Figure 5 The diagram shows a block illustration of the electronic device 3. The electronic device 3 can be an electric motorcycle, electric bicycle, electric car, mobile phone, tablet computer, digital assistant, personal computer, or any other suitable rechargeable device. The electronic device 3 includes the battery protection circuit 1. The electronic device 3 utilizes the battery protection circuit 1. The electronic device 3 may also include other components, such as a battery management module and a control unit, which will not be described in detail here.

[0061] This invention connects a first resistor 50 in series between the current sensing resistor 30 and the first capacitor 40, with the resistance value of the first resistor 50 being much greater than that of the current sensing resistor 30. This allows the second protection circuit 20 to continue protecting the battery and electronic device when the first capacitor 40 is short-circuited, avoiding protection failure and improving the safety of the battery and electronic device. Similarly, by connecting a second resistor 70 in series between the current sensing resistor 30 and the second capacitor 60, with the resistance value of the second resistor 70 being much greater than that of the current sensing resistor 30, the first protection circuit 10 can continue protecting the battery and electronic device when the second capacitor 60 is short-circuited, avoiding protection failure and improving the safety of the battery and electronic device.

[0062] Furthermore, since the current sensing resistor must be a precision resistor, its cost is relatively high. In this case, the first and second protection circuits share a single current sensing resistor. Compared to existing two-stage protection circuits, this saves one current sensing resistor, effectively reducing costs and also reducing heat generation during battery protection circuit operation. Those skilled in the art should recognize that the above embodiments are merely illustrative of this application and not intended to limit it. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of protection claimed in this application.

Claims

1. A battery protection circuit for protecting a battery, the battery protection circuit comprising a first protection circuit and a second protection circuit; characterized by, The battery protection circuit includes: A current-detecting resistor is provided, and both the first protection circuit and the second protection circuit are electrically connected to the two ends of the current-detecting resistor. The first capacitor is electrically connected to the first protection circuit, and the two ends of the first capacitor are respectively electrically connected to the two ends of the current detection resistor. A first resistor is connected in series between the current sensing resistor and the first capacitor, and the resistance value of the first resistor is 10 to 10,000 times the resistance value of the current sensing resistor. The second capacitor is electrically connected to the second protection circuit, and the two ends of the second capacitor are electrically connected to the two ends of the current detection resistor. A second resistor is connected in series between the current-detecting resistor and the second capacitor, and the resistance value of the second resistor is at least 10 times the resistance value of the current-detecting resistor. The first protection circuit includes a first control chip and a first switch module controlled by the first control chip; the first switch module is used to turn on or off the electrical connection between the input / output terminal of the battery protection circuit and the battery electrode. One end of the current sensing resistor is electrically connected to the ground terminal of the first control chip, and the other end of the current sensing resistor is electrically connected to the overcurrent detection terminal of the first control chip through the first resistor.

2. The battery protection circuit as described in claim 1, characterized in that: The second protection circuit includes a second control chip and a second switch module controlled by the second control chip; the second switch module is used to turn on or off the electrical connection between the input / output terminal of the battery protection circuit and the battery electrode. One end of the current sensing resistor is electrically connected to the ground terminal of the second control chip, and the other end of the current sensing resistor is electrically connected to the overcurrent detection terminal of the second control chip.

3. The battery protection circuit as described in claim 2, characterized in that: The other end of the current sensing resistor is electrically connected to the overcurrent detection terminal of the second control chip through the second resistor.

4. A battery, characterized by: The battery application uses the battery protection circuit as described in any one of claims 1-3.

5. An electronic device, characterized in that: The electronic device uses the battery protection circuit as described in any one of claims 1-3.

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