Charging and discharging protection circuit, battery protection board and battery

Abstract

The utility model discloses a charging and discharging protection circuit, a battery protection board and a battery, and relates to the technical field of charging and discharging, a first voltage of a metal foil is obtained through an over-current protection module, and a charging and discharging loop of a charging and discharging power supply is cut off under the condition that the first voltage is greater than a first voltage threshold value; second voltage of the charging and discharging power supply is obtained through the overvoltage protection module, and a loop formed by the charging and discharging power supply and the metal foil is formed under the condition that the second voltage is larger than a second voltage threshold value, so that the metal foil is fused, and the charging and discharging loop of the charging and discharging power supply is cut off, that is, charging and discharging protection is performed on the charging and discharging power supply through the metal foil; compared with a fuse device in the prior art, the metal foil is small in size and adapts to miniaturization design of a circuit board.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of charge and discharge technology, specifically relates to a charge and discharge protection circuit, the protection board of battery and battery. BACKGROUND

[0002] The charge and discharge process of the battery needs charge and discharge protection, that is, in the case of abnormal charge and discharge voltage or abnormal charge and discharge current of the battery, the charge and discharge loop of the battery is cut off.

[0003] In the related art, a fuse device (for example, a three-terminal fuse device) is used to protect the battery from charge and discharge, that is, in the case of abnormal charge and discharge voltage or abnormal charge and discharge current of the battery, the charge and discharge loop of the battery is cut off by fusing the fuse device.

[0004] However, the fuse device is large in size and not suitable for the miniaturization design of a printed circuit board (PCB). UTILITY MODEL CONTENTS

[0005] The utility model provides a charge and discharge protection circuit, the protection board of battery and battery, at least solve the problem of large size of the fuse device for protecting the battery from charge and discharge in the related art, which is not suitable for the miniaturization design of a printed circuit board (PCB).

[0006] To solve the above technical problems, the utility model is realized as follows:

[0007] In a first aspect, the utility model provides a charge and discharge protection circuit, comprising: a metal foil, an overcurrent protection module and an overvoltage protection module;

[0008] The metal foil is electrically connected to the overcurrent protection module and the overvoltage protection module, respectively, and is used to be electrically connected to a charge and discharge power supply;

[0009] The overcurrent protection module is used to be electrically connected to the charge and discharge end of the charge and discharge power supply, obtain the first voltage of the metal foil, and cut off the charge and discharge loop of the charge and discharge power supply in the case that the first voltage is greater than a first voltage threshold;

[0010] The overvoltage protection module is used to be electrically connected to the charge and discharge power supply, obtain the second voltage of the charge and discharge power supply, and form a loop composed of the charge and discharge power supply and the metal foil in the case that the second voltage is greater than a second voltage threshold, so that the metal foil is fused, thereby cutting off the charge and discharge loop of the charge and discharge power supply.

[0011] Optionally, the overcurrent protection module comprises a first control submodule and a first switch submodule; the first switch submodule is electrically connected with the metal foil, and is configured to be electrically connected with the charge-discharge end; the first control submodule is electrically connected with the metal foil and the first switch submodule respectively, and is configured to acquire the first voltage, and control the first switch submodule to be turned on when the first voltage is less than the first voltage threshold, and control the first switch submodule to be turned off when the first voltage is greater than the first voltage threshold.

[0012] Optionally, the first control submodule comprises a first power protection chip; a current detection end of the first power protection chip is electrically connected with a first end of the metal foil, a negative power input end of the first power protection chip is electrically connected with a second end of the metal foil, a charge control end of the first power protection chip is electrically connected with a first control input end of the first switch submodule, and a discharge control end of the first power protection chip is electrically connected with a second control input end of the first switch submodule; a first end of the first switch submodule is electrically connected with a first electrode of the charge-discharge end, and a second end of the first switch submodule is electrically connected with the first end of the metal foil; a second end of the metal foil is electrically connected with a first electrode of the charge-discharge power supply; a second electrode of the charge-discharge end is electrically connected with a second electrode of the charge-discharge power supply.

[0013] Optionally, the first switch submodule comprises a first switch chip, and the first switch chip comprises a first switch device and a second switch device; a first end of the first switch device is electrically connected with a first electrode of the charge-discharge end, a second end of the first switch device is electrically connected with a second end of the second switch device, and a control end of the first switch device is electrically connected with a charge control end of the first control submodule; a first end of the second switch device is electrically connected with a first end of the metal foil, and a control end of the second switch device is electrically connected with a discharge control end of the first control submodule; a current detection end of the first control submodule is electrically connected with the first end of the metal foil, and a negative power input end of the first control submodule is electrically connected with a second end of the metal foil; a second end of the metal foil is electrically connected with a first electrode of the charge-discharge power supply; a second electrode of the charge-discharge end is electrically connected with a second electrode of the charge-discharge power supply.

[0014] Optionally, the overvoltage protection module comprises a second control submodule and a second switch submodule; the second switch submodule is electrically connected with the metal foil, and is used to be electrically connected with the charge-discharge power supply; the second control submodule is electrically connected with the second switch submodule, is used to be electrically connected with the charge-discharge power supply, and acquires a second voltage of the charge-discharge power supply; in the case that the second voltage is greater than a second voltage threshold, the second control submodule controls the second switch submodule to be turned on; and in the case that the second voltage is less than the second voltage threshold, the second control submodule controls the second switch submodule to be turned off.

[0015] Optionally, the second control submodule comprises a second power protection chip; a positive power input end of the second power protection chip is used to be electrically connected with a second electrode of the charge-discharge power supply; control ends of the second power protection chip are respectively electrically connected with a third control input end of the second switch submodule and a fourth control input end of the second switch submodule; a first end of the second switch submodule is electrically connected with the second electrode of the charge-discharge power supply; a second end of the second switch submodule is electrically connected with a first end of the metal foil; a second end of the metal foil is electrically connected with a first electrode of the charge-discharge power supply; a first end of the overcurrent protection module is electrically connected with the first electrode of the charge-discharge end; a second end of the overcurrent protection module is electrically connected with the first end of the metal foil; a current detection end of the overcurrent protection module is electrically connected with the first end of the metal foil; and a negative power input end of the overcurrent protection module is electrically connected with the second end of the metal foil; a second electrode of the charge-discharge end is electrically connected with the second electrode of the charge-discharge power supply.

[0016] Optionally, the second switch submodule comprises a second switch chip, and the second switch chip comprises a plurality of third switch devices; a first end of the third switch device is electrically connected with a first end of the metal foil; a second end of the third switch device is electrically connected with a second electrode of the charge-discharge power supply; and a control end of the third switch device is electrically connected with a control end of the second control submodule; a positive power input end of the second control submodule is used to be electrically connected with the second electrode of the charge-discharge power supply; a second end of the metal foil is electrically connected with a first electrode of the charge-discharge power supply; a first end of the overcurrent protection module is electrically connected with the first electrode of the charge-discharge end; a second end of the overcurrent protection module is electrically connected with the first end of the metal foil; a current detection end of the overcurrent protection module is electrically connected with the first end of the metal foil; and a negative power input end of the overcurrent protection module is electrically connected with the second end of the metal foil; a second electrode of the charge-discharge end is electrically connected with the second electrode of the charge-discharge power supply.

[0017] Optionally, the metal foil is arranged on a surface of a conductive layer of a circuit board or in a hole of the circuit board.

[0018] Optionally, the cross-sectional area of the metal foil is less than the cross-sectional area of the wire in the charge-discharge protection circuit.

[0019] In a second aspect, the utility model also provides a protection board of battery, including the charge-discharge protection circuit as described in the first aspect.

[0020] In a third aspect, the utility model also provides a battery, including the protection board of battery as described in the second aspect.

[0021] In the utility model embodiment, through the overcurrent protection module, the first voltage of the metal foil is acquired, and in the case that the first voltage is greater than the first voltage threshold, the charge-discharge circuit of the charge-discharge power supply is cut off, and through the overvoltage protection module, the second voltage of the charge-discharge power supply is acquired, and in the case that the second voltage is greater than the second voltage threshold, the loop formed by the charge-discharge power supply and the metal foil is formed, so that the metal foil is fused, thereby cutting off the charge-discharge circuit of the charge-discharge power supply, that is, the charge-discharge protection of the charge-discharge power supply is carried out through the metal foil, and the fuse device need not be used, compared with the fuse device in the related art, the metal foil is small in size, and is suitable for the miniaturization design of the circuit board. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical scheme of the utility model embodiment, the following will briefly introduce the drawings needed to be used in the description of the utility model embodiment, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creative labor.

[0023] Figure 1 The structural schematic diagram of the charge-discharge protection circuit provided in the utility model embodiment is shown in the figure.

[0024] Figure 2 The specific structural schematic diagram of the charge-discharge protection circuit provided in the utility model embodiment is shown in the figure.

[0025] Figure 3 The schematic diagram of the metal foil provided in the utility model embodiment is shown in the figure.

[0026] Reference Signs:

[0027] 10-metal foil; 20-overcurrent protection module; 21-first control submodule; 22-first switch submodule; 30-overvoltage protection module; 31-second control submodule; 32-second switch submodule; 40-charging and discharging power supply; 50-charging and discharging end; U1-first power supply protection chip; U2-first switch chip; U3-second power supply protection chip; U4-second switch chip; R1-first resistor; R2-second resistor; R3-third resistor; R4-fourth resistor; C1-first capacitor; C2-second capacitor; C3-third capacitor; C4-fourth capacitor; C5-fifth capacitor; C6-sixth capacitor; Q1-first switch device; Q2-second switch device; Q3-third switch device. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purpose, features and advantages of the utility model more apparent, obvious and easy to understand, the utility model will be further explained in detail below with the help of the drawings and specific embodiments.

[0029] Reference Figure 1 The utility model embodiment provides a kind of charging and discharging protection circuit, comprising: metal foil 10, overcurrent protection module 20 and overvoltage protection module 30;The metal foil 10 is electrically connected with the overcurrent protection module 20 and the overvoltage protection module 30 respectively, and the metal foil 10 is used to be electrically connected with charging and discharging power supply 40;The overcurrent protection module 20 is used to be electrically connected with the charging and discharging end 50 of the charging and discharging power supply 40, and the first voltage of the metal foil 10 is acquired, and in the case where the first voltage is greater than first voltage threshold value, the charging and discharging loop of the charging and discharging power supply 40 is cut off;The overvoltage protection module 30 is used to be electrically connected with the charging and discharging power supply 40, and the second voltage of the charging and discharging power supply 40 is acquired, and in the case where the second voltage is greater than second voltage threshold value, the loop that the charging and discharging power supply 40 and the metal foil 10 constitute is formed, so that the metal foil 10 is fused, to cut off the charging and discharging loop of the charging and discharging power supply 40.

[0030] It needs to be explained that charging and discharging is charging and discharging, and charging and discharging power supply 40 is the power supply that can charge and discharge, for example battery;First voltage threshold value is equal to the product of the charging and discharging current threshold value of charging and discharging power supply 40 and the resistance of metal foil 10, so in the case where the first voltage is greater than first voltage threshold value, it indicates that the charging and discharging current of charging and discharging power supply 40 is greater than charging and discharging current threshold value, and the charging and discharging loop of charging and discharging power supply 40 is cut off to carry out overcurrent protection to charging and discharging power supply 40;In the case where the second voltage is greater than second voltage threshold value, the loop that charging and discharging power supply 40 and metal foil 10 constitute is formed, and the current of charging and discharging power supply 40 directly passes through metal foil 10, so that metal foil 10 is fused, to cut off the charging and discharging loop of charging and discharging power supply 40, to carry out overvoltage protection to charging and discharging power supply 40.

[0031] In some embodiments, the overcharge protection module 30 is configured to determine that the charging and discharging voltage of the charging and discharging power supply 40 is abnormal when the second voltage is greater than the second voltage threshold and the second duration is greater than the second preset duration threshold, and to form a loop composed of the charging and discharging power supply 40 and the metal foil 10 to cause the metal foil 10 to fuse and thereby cut off the charging and discharging loop of the charging and discharging power supply 40 to avoid damage to the charging and discharging power supply 40, thereby achieving overcharge protection of the charging and discharging power supply 40; and to determine that the charging and discharging voltage of the charging and discharging power supply 40 is abnormal for a short time when the second voltage is greater than the second voltage threshold and the second duration is less than or equal to the second preset duration threshold, and to not cause the metal foil 10 to fuse to avoid false triggering of the overcharge protection of the charging and discharging power supply 40.

[0032] In some embodiments, the charging and discharging end 50 is in the form of a connector.

[0033] In some embodiments, the metal foil 10 is a metal sheet, for example, a metal foil 10 with a thickness of 0.035 mm. The metal foil 10 can be a copper foil, an aluminum foil, or a metal foil 10 composed of multiple metals.

[0034] In some embodiments, the metal foil 10 can be in the form of a long strip-shaped filament, an S-shaped filament, a W-shaped filament, or other shapes, for example, as shown in Figure 3 In some embodiments, the metal foil 10 is in the form of a long strip-shaped filament.

[0035] For example, the metal foil 10 is a copper foil, the metal foil 10 is in the form of a long strip-shaped filament, the resistance of the metal foil 10 is 2 mΩ, the resistivity of the metal foil 10 is 18.51 Ω·mm, and the thickness of the metal foil 10 is 0.035 mm. The corresponding relationship between the length and the width of the metal foil 10 is shown in the following table

[0036] (Table 1):

[0037] width length 0.10 0.38 0.20 0.76 0.30 1.14 0.40 1.52 0.50 1.90 0.60 2.28 0.70 2.66 0.80 3.04 0.90 3.42 1.00 3.80

[0038] Table 1

[0039] In some embodiments, the metal foil 10 is in the form of a long strip-shaped filament.

[0040] In the embodiment of the utility model, through overcurrent protection module 20 obtains the first voltage of metal foil 10, and in the case that the first voltage is greater than the first voltage threshold, the charging and discharging circuit of charging and discharging power supply 40 is cut off, and through overvoltage protection module 30 obtains the second voltage of charging and discharging power supply 40, and in the case that the second voltage is greater than the second voltage threshold, the loop formed by charging and discharging power supply 40 and metal foil 10 is formed, so that metal foil 10 is fused, thereby cutting off the charging and discharging circuit of charging and discharging power supply 40, that is, the charging and discharging protection of charging and discharging power supply 40 is carried out through metal foil 10, without using fuse device, compared with fuse device in the related art, metal foil 10 is smaller in size, and is suitable for miniaturization design of circuit board.

[0041] Optionally, in some embodiments, the overcurrent protection module 20 includes a first control submodule 21 and a first switch submodule 22; the first switch submodule 22 is electrically connected with the metal foil 10, and the first switch submodule 22 is used to be electrically connected with the charging and discharging end 50; the first control submodule 21 is electrically connected with the metal foil 10 and the first switch submodule 22 respectively, and the first control submodule 21 is used to obtain the first voltage, and in the case that the first voltage is less than the first voltage threshold, the first switch submodule 22 is controlled to be turned on, and in the case that the first voltage is greater than the first voltage threshold, the first switch submodule 22 is controlled to be turned off.

[0042] In the embodiment of the utility model, the first voltage is obtained through the first control submodule 21, and in the case that the first voltage is less than the first voltage threshold, the first switch submodule 22 is controlled to be turned on, the charging and discharging circuit of charging and discharging power supply 40 is formed, and the charging and discharging of charging and discharging power supply 40 is carried out; in the case that the first voltage is greater than the first voltage threshold, the first switch submodule 22 is controlled to be turned off through the first control submodule 21, so as to cut off the charging and discharging circuit of charging and discharging power supply 40, and the charging and discharging of charging and discharging power supply 40 is stopped.

[0043] Optionally, in some embodiments, the first control submodule 21 comprises a first power protection chip U1; a current detection end a1 of the first power protection chip U1 is electrically connected with the first end of the metal foil 10, a negative power input end a2 of the first power protection chip U1 is electrically connected with the second end of the metal foil 10, a charging control end a3 of the first power protection chip U1 is electrically connected with the first control input end of the first switch submodule 22, a discharging control end a4 of the first power protection chip U1 is electrically connected with the second control input end of the first switch submodule 22; the first end of the first switch submodule 22 is electrically connected with the first electrode of the charge-discharge end 50, the second end of the first switch submodule 22 is electrically connected with the first end of the metal foil 10; the second end of the metal foil 10 is electrically connected with the first electrode of the charge-discharge power supply 40; the second electrode of the charge-discharge end 50 is electrically connected with the second electrode of the charge-discharge power supply 40.

[0044] In some embodiments, the specific form of the charge-discharge end 50 is a connector, the first electrode of the charge-discharge end 50 comprises three first connection ends b2, and the second electrode of the charge-discharge end 50 comprises three second connection ends b1; the first end of the first switch submodule 22 is electrically connected with each first connection end b2, and the second electrode of the charge-discharge power supply 40 is electrically connected with each second connection end b1.

[0045] In some embodiments, in the case of charging of the charge-discharge power supply 40, the conduction and disconnection of the first switch submodule 22 are controlled through the charging control end a3 of the first power protection chip U1; in the case of discharging of the charge-discharge power supply 40, the conduction and disconnection of the first switch submodule 22 are controlled through the discharging control end a4 of the first power protection chip U1.

[0046] In some embodiments, the first electrode is a negative electrode, and the second electrode is a positive electrode.

[0047] In some embodiments, the first control submodule 21 further comprises a first resistor R1, a second resistor R2 and a first capacitor C1; the first end of the first resistor R1 is electrically connected with the positive power input end a5 of the first power protection chip U1, and the second end of the first resistor R1 is electrically connected with the second electrode of the charge-discharge power supply 40; the first end of the first capacitor C1 is electrically connected with the positive power input end a5 of the first power protection chip U1, and the second end of the first capacitor C1 is electrically connected with the negative power input end a2 of the first power protection chip U1; the first end of the second resistor R2 is electrically connected with the voltage detection end a6 of the first power protection chip U1, and the second end of the second resistor R2 is electrically connected with the first end of the first switch submodule 22; wherein the first resistor R1 and the second resistor R2 are current-limiting resistors, and the first capacitor C1 is a filter capacitor.

[0048] In some embodiments, the first power protection chip U1 controls the first switch sub-module 22 to be turned off to cut off the charging and discharging circuit of the charging and discharging power supply 40 and the charging and discharging power supply 40 stops charging and discharging when the first voltage is greater than the first voltage threshold and the first time duration is greater than the first preset time duration threshold; the charging and discharging power supply 40 charges and discharges to avoid damage to the charging and discharging power supply 40 when the first voltage is greater than the first voltage threshold and the first time duration is less than or equal to the first preset time duration threshold, which indicates that the charging and discharging current of the charging and discharging power supply 40 is abnormal for a short time and does not harm the charging and discharging power supply 40, and the charging and discharging protection of the first power protection chip U1 does not need to be triggered.

[0049] In the embodiments of the utility model, the first power protection chip U1 acquires the first voltage, and controls the first switch sub-module 22 to be turned on to form the charging and discharging circuit of the charging and discharging power supply 40 and the charging and discharging power supply 40 charges and discharges when the first voltage is less than the first voltage threshold; the first power protection chip U1 controls the first switch sub-module 22 to be turned off to cut off the charging and discharging circuit of the charging and discharging power supply 40 and the charging and discharging power supply 40 stops charging and discharging when the first voltage is greater than the first voltage threshold.

[0050] Optionally, in some embodiments, the first switch sub-module 22 comprises a first switch chip U2, and the first switch chip U2 comprises a first switch device Q1 and a second switch device Q2; the first end of the first switch device Q1 is electrically connected with the first electrode of the charging and discharging end 50, the second end of the first switch device Q1 is electrically connected with the second end of the second switch device Q2, and the control end of the first switch device Q1 is electrically connected with the charging control end of the first control sub-module 21; the first end of the second switch device Q2 is electrically connected with the first end of the metal foil 10, and the control end of the second switch device Q2 is electrically connected with the discharging control end of the first control sub-module 21; the current detection end of the first control sub-module 21 is electrically connected with the first end of the metal foil 10, and the negative power input end of the first control sub-module 21 is electrically connected with the second end of the metal foil 10; the second end of the metal foil 10 is electrically connected with the first electrode of the charging and discharging power supply 40; and the second electrode of the charging and discharging end 50 is electrically connected with the second electrode of the charging and discharging power supply 40.

[0051] In some embodiments, the specific form of the charge-discharge end 50 is a connector, the first electrode of the charge-discharge end 50 includes three first connection ends b2, and the second electrode of the charge-discharge end 50 includes three second connection ends b1; the first end of the first switching device Q1 is electrically connected with each first connection end b2, and the second electrode of the charge-discharge power supply 40 is electrically connected with each second connection end b1.

[0052] In some embodiments, the first switching device Q1 and the second switching device Q2 are both MOS tubes (Metal-Oxide-Semiconductor Field-Effect Transistor), including PMOS tubes (positive channel Metal Oxide Semiconductor) and NMOS tubes (Negative channel-Metal-Oxide-Semiconductor).

[0053] For example, the first switching device Q1 and the second switching device Q2 are both NMOS tubes, the first end of the first switching device Q1 is the source of the first switching device Q1, the second end of the first switching device Q1 is the drain of the first switching device Q1, the first end of the second switching device Q2 is the source of the second switching device Q2, and the second end of the second switching device Q2 is the drain of the second switching device Q2.

[0054] In some embodiments, the first switching sub-module 22 further includes a second capacitor C2 and a third capacitor C3; the first end of the third capacitor C3 is electrically connected with the first end of the first switching device Q1, the second end of the third capacitor C3 is electrically connected with the first end of the second capacitor C2, and the second end of the second capacitor C2 is electrically connected with the first end of the second switching device Q2; wherein the second capacitor C2 and the third capacitor C3 are filter capacitors.

[0055] In the embodiments of the utility model, the first switching sub-module 22 is controlled to be turned on and turned off by the charging control end of the first control sub-module 21 in the case that the charge-discharge power supply 40 is charging; and the first switching sub-module 22 is controlled to be turned on and turned off by the discharging control end of the first control sub-module 21 in the case that the charge-discharge power supply 40 is discharging.

[0056] Optionally, in some embodiments, the overvoltage protection module 30 comprises a second control submodule 31 and a second switch submodule 32; the second switch submodule 32 is electrically connected with the metal foil 10, and the second switch submodule 32 is used to be electrically connected with the charge-discharge power supply 40; the second control submodule 31 is electrically connected with the second switch submodule 32, and the second control submodule 31 is used to be electrically connected with the charge-discharge power supply 40, to acquire a second voltage of the charge-discharge power supply 40, and to control the second switch submodule 32 to be turned on when the second voltage is greater than a second voltage threshold, and to control the second switch submodule 32 to be turned off when the second voltage is less than the second voltage threshold.

[0057] In the embodiment of the utility model, the second control submodule 31 acquires the second voltage of the charge-discharge power supply 40, and controls the second switch submodule 32 to be turned off when the second voltage is less than the second voltage threshold, to maintain the charge-discharge loop of the charge-discharge power supply 40; the second control submodule 31 controls the second switch submodule 32 to be turned on when the second voltage is greater than the second voltage threshold, to form a loop composed of the charge-discharge power supply 40 and the metal foil 10, so that the metal foil 10 is fused, thereby cutting off the charge-discharge loop of the charge-discharge power supply 40.

[0058] Optionally, in some embodiments, the second control submodule 31 comprises a second power protection chip U3; a positive power input end d1 of the second power protection chip U3 is used to be electrically connected with the second electrode of the charge-discharge power supply 40, a control end d2 of the second power protection chip U3 is respectively electrically connected with a third control input end of the second switch submodule 32 and a fourth control input end of the second switch submodule 32; a first end of the second switch submodule 32 is electrically connected with the second electrode of the charge-discharge power supply 40, and a second end of the second switch submodule 32 is electrically connected with a first end of the metal foil 10; a second end of the metal foil 10 is electrically connected with the first electrode of the charge-discharge power supply 40; a first end of the overcurrent protection module 20 is electrically connected with the first electrode of the charge-discharge end 50, and a second end of the overcurrent protection module 20 is electrically connected with the first end of the metal foil 10; a current detection end of the overcurrent protection module 20 is electrically connected with the first end of the metal foil 10, and a negative power input end of the overcurrent protection module 20 is electrically connected with the second end of the metal foil 10; a second electrode of the charge-discharge end 50 is electrically connected with the second electrode of the charge-discharge power supply 40.

[0059] In some embodiments, the second control submodule 31 further comprises a third resistor R3 and a fourth capacitor C4, a first end of the third resistor R3 is electrically connected with the positive power input end d1 of the second power protection chip U3, and a second end of the third resistor R3 is electrically connected with the second electrode of the charge-discharge power supply 40; a first end of the fourth capacitor C4 is electrically connected with the positive power input end d1 of the second power protection chip U3, and a second end of the fourth capacitor C4 is electrically connected with the negative power input end d3 of the second power protection chip U3; the negative power input end d3 of the second power protection chip U3 is electrically connected with the first electrode of the charge-discharge power supply 40, and a voltage detection end d4 of the second power protection chip U3 is grounded; wherein the third resistor R3 is a current-limiting resistor, and the fourth capacitor C4 is a filter capacitor.

[0060] In some embodiments, when the second voltage is greater than the second voltage threshold for a second duration, and the second duration is greater than a second preset duration threshold, it indicates that the charge-discharge voltage of the charge-discharge power supply 40 is abnormal, the second switch submodule 32 is controlled to be turned on to form a loop composed of the charge-discharge power supply 40 and the metal foil 10, so that the metal foil 10 is fused to cut off the charge-discharge loop of the charge-discharge power supply 40, thereby avoiding damage to the charge-discharge power supply 40; when the second voltage is greater than the second voltage threshold for a second duration, and the second duration is less than or equal to the second preset duration threshold, it indicates that the charge-discharge voltage of the charge-discharge power supply 40 is abnormal for a short time, and the charge-discharge protection of the second power protection chip U3 does not need to be triggered, and the second switch submodule 32 is controlled to be turned off to avoid false triggering of the charge-discharge protection of the second power protection chip U3.

[0061] In the embodiments of the utility model, the second voltage of the charge-discharge power supply 40 is acquired by the second power protection chip U3, and when the second voltage is less than the second voltage threshold, it indicates that the charge-discharge voltage of the charge-discharge power supply 40 is normal, and the second switch submodule 32 is controlled to be turned off to maintain the charge-discharge loop of the charge-discharge power supply 40; when the second voltage is greater than the second voltage threshold, the second switch submodule 32 is controlled to be turned on to form a loop composed of the charge-discharge power supply 40 and the metal foil 10, so that the metal foil 10 is fused to cut off the charge-discharge loop of the charge-discharge power supply 40.

[0062] In some embodiments, the specific form of the charge-discharge end 50 is a connector, the first electrode of the charge-discharge end 50 comprises three first connection ends b2, and the second electrode of the charge-discharge end 50 comprises three second connection ends b1; the first end of the overcurrent protection module 20 is electrically connected with each first connection end b2, and the first end of the first switch device Q1 is electrically connected with each second connection end b1.

[0063] Optionally, in some embodiments, the second switch sub-module 32 comprises a second switch chip U4, the second switch chip U4 comprises a plurality of third switch devices Q3; the first end of the third switch device Q3 is electrically connected with the first end of the metal foil 10, the second end of the third switch device Q3 is electrically connected with the second electrode of the charge-discharge power supply 40, and the control end of the third switch device Q3 is electrically connected with the control end of the second control sub-module 31; the positive power input end of the second control sub-module 31 is used for being electrically connected with the second electrode of the charge-discharge power supply 40; the second end of the metal foil 10 is electrically connected with the first electrode of the charge-discharge power supply 40; the first end of the overcurrent protection module 20 is electrically connected with the first electrode of the charge-discharge end 50, and the second end of the overcurrent protection module 20 is electrically connected with the first end of the metal foil 10; the current detection end of the overcurrent protection module 20 is electrically connected with the first end of the metal foil 10, and the negative power input end of the overcurrent protection module 20 is electrically connected with the second end of the metal foil 10; the second electrode of the charge-discharge end 50 is electrically connected with the second electrode of the charge-discharge power supply 40.

[0064] In some embodiments, the third switch device Q3 is an NMOS tube or a PMOS tube, for example, the third switch device Q3 is an NMOS tube, the first end of the third switch device Q3 is the source electrode of the third switch device Q3, the second end of the third switch device Q3 is the drain electrode of the third switch device Q3, and the control end of the third switch device Q3 is the gate electrode of the third switch device Q3.

[0065] In some embodiments, the second switch sub-module 32 further comprises a fourth resistance R4, the first end of the fourth resistance R4 is electrically connected with the control end of the third switch device Q3, and the second end of the fourth resistance R4 is electrically connected with the first end of the third switch device Q3; wherein the fourth resistance R4 is a voltage stabilizing resistance.

[0066] In the embodiment of the utility model, the second control sub-module 31 obtains the second voltage of the charge-discharge power supply 40, and in the case that the second voltage is less than the second voltage threshold value, it is indicated that the charge-discharge voltage of the charge-discharge power supply 40 is normal, controls each third switch device Q3 to be disconnected, so as to maintain the charge-discharge loop of the charge-discharge power supply 40; the second control sub-module 31 controls each third switch device Q3 to be turned on in the case that the second voltage is greater than the second voltage threshold value, forms the loop composed of the charge-discharge power supply 40 and the metal foil 10, so that the metal foil 10 is fused, thereby cutting off the charge-discharge loop of the charge-discharge power supply 40.

[0067] Optionally, in some embodiments, the metal foil 10 is arranged on the surface of the conductive layer of the circuit board or in the hole of the circuit board.

[0068] It should be noted that the conductive layer of the circuit board includes a conductive layer inside the inner circuit board and a conductive layer on the surface of the circuit board; the metal foil 10 is arranged in the hole of the circuit board to form a via hole of the circuit board or the metal foil 10 is completely filled in the hole of the circuit board, wherein the via hole of the circuit board includes a blind hole, a through hole, a buried hole and the like of the circuit board.

[0069] In the related art, a fuse device (such as a three-terminal fuse device) and a precision resistor are used to protect the battery from charging and discharging, that is, in the case of abnormal charging and discharging voltage or current of the battery, the charging and discharging circuit of the battery is cut off by fusing the fuse device, and the charging and discharging circuit of the battery is cut off by the precision resistor in the case of abnormal charging and discharging current; since the fuse device and the precision resistor are arranged on the surface of the circuit board, they occupy the external space of the circuit board, which is not suitable for the miniaturization design of the circuit board; and the precision resistor increases the internal resistance of the circuit, thereby increasing the heat generation of the circuit.

[0070] In the embodiments of the present application, the metal foil 10 is used to protect the battery from charging and discharging, and the metal foil 10 is arranged in the conductive layer inside the circuit board or the hole of the circuit board, which does not occupy the external space of the circuit board, thereby saving the external space of the circuit board and adapting to the miniaturization design of the circuit board; by arranging the metal foil 10 on the conductive layer outside the circuit board, since the volume of the metal foil 10 is smaller than the volume of the fuse device and smaller than the volume of the precision resistor, the external space of the circuit board is saved, and the miniaturization design of the circuit board is adapted; in addition, compared with the use of the fuse device and the precision resistor to protect the battery from charging and discharging in the related art, the use of the metal foil 10 realizes the functions of the fuse device and the precision resistor, and the use of the metal foil 10 to protect the battery from charging and discharging can reduce the internal resistance of the circuit, thereby reducing the heat generation of the circuit.

[0071] By using the metal foil 10 to protect the battery from charging and discharging, overcharging can be prevented to cause the battery to catch fire and explode.

[0072] For example, in the related art, a three-terminal fuse device and a precision resistor are used to protect the battery from charging and discharging, the length of the circuit board is 50 mm, the width of the circuit board is 4 mm, the length of the three-terminal fuse device is 4 mm, and the length of the precision resistor is 4 mm, so that the three-terminal fuse device occupies a space of 4 mm in the length direction of the circuit board, and the precision resistor occupies a space of 4 mm in the length direction of the circuit board.

[0073] By arranging the metal foil 10 in the conductive layer inside the circuit board or the hole of the circuit board in the embodiments of the present application, the space occupied by the three-terminal fuse device and the precision resistor in the related art can be saved, wherein it is known from (4+4) / 50x100% that 16% of the space in the length direction of the circuit board is saved by the embodiments of the present application.

[0074] In the embodiment of the utility model, because the metal foil 10 can be arranged on the surface of the conductive layer of the circuit board or in the hole of the circuit board, the circuit board of different types and different circuits can be adapted.

[0075] Optionally, in some embodiments, the cross-sectional area of the metal foil 10 is smaller than the cross-sectional area of the wire in the charge and discharge protection circuit.

[0076] For example, referring to Figure 3 On the circuit board A1, the cross-sectional area of the metal foil 10 is smaller than the cross-sectional area of the wire A2 in the charge and discharge protection circuit.

[0077] In the embodiment of the utility model, because the resistance of the conductor is negatively related to the cross-sectional area of the conductor, the heat generation of the conductor is positively related to the resistance of the conductor, the greater the heat generation of the conductor, the more easily the conductor is fused, the smaller the cross-sectional area of the conductor, the more easily the conductor is fused, and the cross-sectional area of the metal foil 10 is smaller than the cross-sectional area of the wire in the charge and discharge protection circuit, so that the metal foil 10 can be fused without fusing the wire when the charge and discharge current of the battery is greater than the charge and discharge current threshold, thereby protecting other devices in the charge and discharge protection circuit including the wire; after the metal foil 10 is fused, the circuit board of the charge and discharge protection circuit can be reused by replacing the metal foil 10.

[0078] In some embodiments, the charge and discharge protection circuit further comprises a fifth capacitor C5 and a sixth capacitor C6, the first end of the fifth capacitor C5 is electrically connected with the second electrode of the charge and discharge end 50, the second end of the fifth capacitor C5 is electrically connected with the first end of the sixth capacitor C6, and the second end of the sixth capacitor C6 is electrically connected with the first electrode of the charge and discharge end 50; wherein the fifth capacitor C5 and the sixth capacitor C6 are both filter capacitors.

[0079] Specifically, in some embodiments, the charge and discharge protection circuit comprises a metal foil 10, an overcurrent protection module 20 and an overvoltage protection module 30; the overcurrent protection module 20 comprises a first control submodule 21 and a first switch submodule 22; the first control submodule 21 comprises a first power supply protection chip U1; the first switch submodule 22 comprises a first switch chip U2, and the first switch chip U2 comprises a first switch device Q1 and a second switch device Q2; the overvoltage protection module 30 comprises a second control submodule 31 and a second switch submodule 32; the second control submodule 31 comprises a second power supply protection chip U3; the second switch submodule 32 comprises a second switch chip U4, and the second switch chip U4 comprises a plurality of third switch devices Q3.

[0080] The current detection end a1 of the first power protection chip U1 is electrically connected with the first end of the metal foil 10, the negative power input end a2 of the first power protection chip U1 is electrically connected with the second end of the metal foil 10, the charge control end a3 of the first power protection chip U1 is electrically connected with the control end of the first switch device Q1, and the discharge control end a4 of the first power protection chip U1 is electrically connected with the control end of the second switch device Q2.

[0081] The first end of the first switch device Q1 is electrically connected with the first electrode of the charge-discharge end 50, and the second end of the first switch device Q1 is electrically connected with the second end of the second switch device Q2.

[0082] The second end of the metal foil 10 is electrically connected with the first electrode of the charge-discharge power supply 40, and the second electrode of the charge-discharge end 50 is electrically connected with the second electrode of the charge-discharge power supply 40.

[0083] The positive power input end d1 of the second power protection chip U3 is electrically connected with the second electrode of the charge-discharge power supply 40, the control end d2 of the second power protection chip U3 is electrically connected with the control end of each third switch device Q3, the first end of the third switch device Q3 is electrically connected with the first end of the metal foil 10, and the second end of the third switch device Q3 is electrically connected with the second electrode of the charge-discharge power supply 40.

[0084] The utility model also provides a protection board of battery, including the charge-discharge protection circuit as described in first aspect.

[0085] The specific implementation mode of the charge-discharge protection circuit in the protection board of battery is similar to the implementation mode of the charge-discharge protection circuit, and details are not repeated here.

[0086] It should be noted that the protection board of battery is a circuit board.

[0087] The utility model also provides a battery, including the protection board of battery as described in second aspect.

[0088] The specific implementation mode of the charge-discharge protection circuit in the battery is similar to the implementation mode of the charge-discharge protection circuit, and details are not repeated here.

[0089] In summary, by obtaining the first voltage of the metal foil 10 through the overcurrent protection module 20 and cutting off the charging and discharging circuit of the charging and discharging power supply 40 when the first voltage is greater than the first voltage threshold, and by obtaining the second voltage of the charging and discharging power supply 40 through the overvoltage protection module 30 and forming a circuit composed of the charging and discharging power supply 40 and the metal foil 10 when the second voltage is greater than the second voltage threshold, the metal foil 10 melts, thereby cutting off the charging and discharging circuit of the charging and discharging power supply 40, that is, the charging and discharging power supply 40 is protected by the metal foil 10 without the need for a fuse. Compared with the fuse in related technologies, the metal foil 10 is smaller in size and suitable for the miniaturization design of circuit boards.

[0090] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device.

[0091] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

[0092] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A charge / discharge protection circuit, characterized in that, include: Metal foil (10), overcurrent protection module (20), and overvoltage protection module (30); The metal foil (10) is electrically connected to the overcurrent protection module (20) and the overvoltage protection module (30) respectively, and the metal foil (10) is used to be electrically connected to the charging and discharging power supply (40); The overcurrent protection module (20) is used to be electrically connected to the charging and discharging terminal (50) of the charging and discharging power supply (40), and to obtain the first voltage of the metal foil (10), and to cut off the charging and discharging circuit of the charging and discharging power supply (40) when the first voltage is greater than the first voltage threshold. The overvoltage protection module (30) is used to be electrically connected to the charging and discharging power supply (40), and to obtain the second voltage of the charging and discharging power supply (40). When the second voltage is greater than the second voltage threshold, a circuit is formed between the charging and discharging power supply (40) and the metal foil (10), so that the metal foil (10) melts and thereby cuts off the charging and discharging circuit of the charging and discharging power supply (40).

2. The charge / discharge protection circuit according to claim 1, characterized in that, The overcurrent protection module (20) includes a first control submodule (21) and a first switch submodule (22); The first switch submodule (22) is electrically connected to the metal foil (10), and the first switch submodule (22) is used to be electrically connected to the charging and discharging terminal (50); The first control submodule (21) is electrically connected to the metal foil (10) and the first switch submodule (22) respectively. The first control submodule (21) is used to acquire the first voltage, and control the first switch submodule (22) to turn on when the first voltage is less than the first voltage threshold, and control the first switch submodule (22) to turn off when the first voltage is greater than the first voltage threshold.

3. The charge / discharge protection circuit according to claim 2, characterized in that, The first control submodule (21) includes a first power protection chip (U1); The current detection terminal (a1) of the first power protection chip (U1) is electrically connected to the first end of the metal foil (10), the negative power input terminal (a2) of the first power protection chip (U1) is electrically connected to the second end of the metal foil (10), the charging control terminal (a3) ​​of the first power protection chip (U1) is electrically connected to the first control input terminal of the first switch submodule (22), and the discharging control terminal (a4) of the first power protection chip (U1) is electrically connected to the second control input terminal of the first switch submodule (22). The first end of the first switch submodule (22) is electrically connected to the first electrode of the charging / discharging terminal (50), and the second end of the first switch submodule (22) is electrically connected to the first end of the metal foil (10); The second end of the metal foil (10) is electrically connected to the first electrode of the charging and discharging power supply (40); The second electrode of the charging / discharging terminal (50) is electrically connected to the second electrode of the charging / discharging power supply (40).

4. The charge / discharge protection circuit according to claim 2, characterized in that, The first switch submodule (22) includes a first switch chip (U2), and the first switch chip (U2) includes a first switch device (Q1) and a second switch device (Q2); The first end of the first switching device (Q1) is electrically connected to the first electrode of the charging and discharging terminal (50), the second end of the first switching device (Q1) is electrically connected to the second end of the second switching device (Q2), and the control terminal of the first switching device (Q1) is electrically connected to the charging control terminal of the first control submodule (21). The first end of the second switching device (Q2) is electrically connected to the first end of the metal foil (10), and the control end of the second switching device (Q2) is electrically connected to the discharge control end of the first control submodule (21). The current detection terminal of the first control submodule (21) is electrically connected to the first end of the metal foil (10), and the negative power input terminal of the first control submodule (21) is electrically connected to the second end of the metal foil (10). The second end of the metal foil (10) is electrically connected to the first electrode of the charging and discharging power supply (40); The second electrode of the charging / discharging terminal (50) is electrically connected to the second electrode of the charging / discharging power supply (40).

5. The charge / discharge protection circuit according to claim 1, characterized in that, The overvoltage protection module (30) includes a second control submodule (31) and a second switch submodule (32); The second switch submodule (32) is electrically connected to the metal foil (10), and the second switch submodule (32) is used to be electrically connected to the charging and discharging power supply (40); The second control submodule (31) is electrically connected to the second switch submodule (32). The second control submodule (31) is used to connect to the charging and discharging power supply (40) and obtain the second voltage of the charging and discharging power supply (40). When the second voltage is greater than the second voltage threshold, the second switch submodule (32) is turned on, and when the second voltage is less than the second voltage threshold, the second switch submodule (32) is turned off.

6. The charge / discharge protection circuit according to claim 5, characterized in that, The second control submodule (31) includes a second power protection chip (U3); The positive power input terminal (d1) of the second power protection chip (U3) is used to be electrically connected to the second electrode of the charging and discharging power supply (40), and the control terminal (d2) of the second power protection chip (U3) is electrically connected to the third control input terminal and the fourth control input terminal of the second switch submodule (32) respectively. The first end of the second switch submodule (32) is electrically connected to the second electrode of the charging and discharging power supply (40), and the second end of the second switch submodule (32) is electrically connected to the first end of the metal foil (10); The second end of the metal foil (10) is electrically connected to the first electrode of the charging and discharging power supply (40); The first end of the overcurrent protection module (20) is electrically connected to the first electrode of the charging / discharging terminal (50), and the second end of the overcurrent protection module (20) is electrically connected to the first end of the metal foil (10); the current detection terminal of the overcurrent protection module (20) is electrically connected to the first end of the metal foil (10), and the negative power input terminal of the overcurrent protection module (20) is electrically connected to the second end of the metal foil (10); The second electrode of the charging / discharging terminal (50) is electrically connected to the second electrode of the charging / discharging power supply (40).

7. The charge / discharge protection circuit according to claim 5, characterized in that, The second switch submodule (32) includes a second switch chip (U4), and the second switch chip (U4) includes a plurality of third switch devices (Q3); The first end of the third switching device (Q3) is electrically connected to the first end of the metal foil (10), the second end of the third switching device (Q3) is electrically connected to the second electrode of the charging and discharging power supply (40), and the control end of the third switching device (Q3) is electrically connected to the control end of the second control submodule (31). The positive power input terminal of the second control submodule (31) is used to be electrically connected to the second electrode of the charging and discharging power supply (40); The second end of the metal foil (10) is electrically connected to the first electrode of the charging and discharging power supply (40); The first end of the overcurrent protection module (20) is electrically connected to the first electrode of the charging / discharging terminal (50), and the second end of the overcurrent protection module (20) is electrically connected to the first end of the metal foil (10); the current detection terminal of the overcurrent protection module (20) is electrically connected to the first end of the metal foil (10), and the negative power input terminal of the overcurrent protection module (20) is electrically connected to the second end of the metal foil (10); The second electrode of the charging / discharging terminal (50) is electrically connected to the second electrode of the charging / discharging power supply (40).

8. The charge / discharge protection circuit according to any one of claims 1 to 7, characterized in that, The metal foil (10) is disposed on the conductive layer surface of the circuit board or in a hole of the circuit board.

9. The charge / discharge protection circuit according to any one of claims 1 to 7, characterized in that, The cross-sectional area of ​​the metal foil (10) is smaller than the cross-sectional area of ​​the wires in the charge-discharge protection circuit.

10. A protection board for a battery, characterized in that, Includes the charge / discharge protection circuit as described in any one of claims 1 to 9.

11. A battery, characterized in that, Includes the protection board for the battery as described in claim 10.

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