Protection Circuit

Abstract

The subject of the present invention is to realize a protection circuit and a battery pack that protect a battery pack from overcharging and overheating with a simpler structure. The present invention provides a protection circuit that protects a battery pack of a secondary battery such as a lithium-ion battery from overcharging and overheating, and comprises: a battery pack, which is formed by connecting one or more cells of a secondary battery; a signal control unit, which outputs a control signal according to the voltage of the cell or the battery pack; a first switch element and a second switch element, which are connected in parallel to a current circuit between the battery pack and an external terminal, and receive a signal from the signal control unit to perform on / off control; and a protection element, which has a built-in fuse assembly and a thermistor, the fuse assembly is connected in parallel to a discharge circuit, and the operation of the thermistor is controlled by a third switch element connected to the signal control unit.

Description

Technical Field

[0001] The present invention relates to a protection device, a protection circuit and a battery pack having a protection element. The protection element has a thermistor and a fuse assembly. Background Art

[0002] Even if lithium-ion batteries are in the form of single cells, such as those used in mobile phones, they must be manufactured in the form of battery packs. The battery pack form here refers to the lithium-ion battery and the protection circuit (Safety Unit) for ensuring safety are assembled in a housing. The reason is that it is difficult to ensure the safety of a single lithium-ion battery in practical use. The safety characteristics of lithium-ion batteries include poor tolerance to overcharging and overheating. Therefore, the battery pack is made by housing the protection circuit, protection element, fuse, etc. for ensuring safety in conjunction with the battery in an outer can such as a plastic housing. While detecting voltage, current, temperature, etc., the charge and discharge of the battery is controlled by a charge and discharge control system (battery management system, BMS).

[0003] A battery pack equipped with several lithium-ion secondary battery cells has a protection element connected in series with the battery to prevent the battery from charging or discharging under abnormal conditions. The protection element cuts off the current when the battery is charging or discharging under abnormal conditions. In order to cut off the battery current in an abnormal situation, the protection element has a built-in fuse component made of a low-melting-point metal that will melt due to the Joule heat of the overcurrent. Furthermore, the protection element has a built-in thermistor. When there is an abnormality that the battery is overcharged, the thermistor can be energized to heat and melt the low-melting-point metal fuse component in a short time. (See Patent Document 1)

[0004] The protection element is connected to the protection circuit of the battery pack, and the action of the fuse component is controlled by a protection integrated circuit (Protection IC) that monitors the voltage of each cell and a control element such as a field effect transistor (FET). For example, the protection element used in the charge and discharge control circuit of the battery pack described in Patent Document 2 forcibly activates the fuse by sensing the overcurrent of the battery pack and the rise in the ambient temperature or by energizing the thermistor under predetermined conditions, thereby cutting off the circuit. That is, when the protection circuit detects an abnormality in the machine, the protection element can heat the resistance element through a signal current, and use the heat to melt the fuse component (also called a fuse element) containing a fusible alloy to cut off the circuit, or cut off the circuit by melting the fuse component through an overcurrent, thereby achieving machine safety.

[0005] The structure of the previous battery pack is relatively complicated. That is, several protection elements are required in the protection circuit, and different protection elements are used in at least the discharge system and the charging system respectively. In addition, the protection circuit requires multiple semiconductor elements including FETs (switching elements) and diodes (rectifier elements) that constitute switches, of which at least two are used in the discharge circuit system, two are used in the charging circuit system, and another one is used to control the action of the protection element. The two signals output from the switching control unit to the first and second switches must always be inverted to each other. The reason is that if the signals are in phase, a loop will be formed between the two switches and the two protection elements, and therefore, there is a risk of causing system failure. The existing protection circuit has the above risk when performing signal control.

[0006] [Prior art literature]

[0007] [Patent Document]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2017-228379

[0009] [Patent Document 2] Japanese Patent Application Publication No. 2012-231649 Summary of the invention

[0010] (Problems to be solved by the invention)

[0011] The present invention is proposed for the purpose of realizing a protection circuit and a battery pack for protecting a battery from overcharging and overheating with a simpler structure, thereby reducing the system risks.

[0012] (Technical means to solve the problem)

[0013] According to the present invention, a protection circuit is provided, which protects a battery pack of a secondary battery such as a lithium-ion battery from overcharging and overheating, and has:

[0014] A battery pack (battery), which is composed of one or more secondary battery cells connected together; a signal control unit, which outputs a control signal according to the voltage of the cell or the battery pack; a first switch element and a second switch element, which are connected in parallel to a current circuit between the battery pack and an external terminal, and receive a signal from the signal control unit to perform on / off control; and a protection element, which has a built-in fuse assembly and a thermistor, the fuse assembly is connected in parallel to a discharge circuit, and the operation of the thermistor is controlled by a third switch element connected to the signal control unit.

[0015] The switch element of the present invention includes a field effect transistor (FET), a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), or other switch transistors or a protection circuit module including the switch element.

[0016] The protection circuit of the present invention is applied to a charging and discharging device of a battery pack. That is, a charging and discharging device is provided, which is a charging and discharging device of a battery pack of a secondary battery such as a lithium-ion battery, and comprises: a battery pack, which is formed by connecting one or more secondary battery cells; a signal control unit, which outputs a control signal according to the voltage of the cell or the battery pack; a first switch element and a second switch element, which are connected in parallel to a current circuit between the battery pack and an external terminal, and receive a signal from the signal control unit to perform on / off control; and a protection element, which has a built-in fuse component and a thermistor, the fuse component is connected in parallel to the discharge circuit, and the thermistor The action of the thermistor is controlled by a third switch element connected to a signal control unit; the signal control unit can disconnect the first switch element and connect the second switch element during charging, and connect the first switch element and disconnect the second switch element during discharging, thereby controlling the on / off of the charging circuit and the discharging circuit, and the protection element has a fuse component, which is blown when the value of the current flowing through the charging circuit of the second switch element exceeds a predetermined fusing current value, or is blown by the heating caused by the power supply of the thermistor when the voltage of the single cell or the battery pack exceeds a predetermined voltage value.

[0017] The protection circuit or charging and discharging device of the present invention is applied to a battery pack. That is, a battery pack is provided, which is a battery pack of a secondary battery such as a lithium-ion battery, and comprises: a battery pack, which is formed by connecting one or more secondary battery cells; a signal control unit, which outputs a control signal according to the voltage of the cell or the battery pack; a first switch element and a second switch element, which are connected in parallel to the current circuit between the battery pack and the external terminal, and receive a signal from the signal control unit to perform on / off control; and a protection element, which has a built-in fuse component and a thermistor, the fuse component is connected in parallel to the discharge circuit, and the action of the thermistor is controlled by the signal control unit connected to the signal control unit. The signal control unit controls the charging circuit and the discharging circuit by controlling the third switch element of the control unit; the signal control unit disconnects the first switch element and connects the second switch element during charging, and connects the first switch element and disconnects the second switch element during discharging, thereby controlling the on / off of the charging circuit and the discharging circuit; the protection element is that when the value of the current of the charging circuit flowing through the second switch element exceeds a predetermined fuse current value, the fuse component blows to cut off the charging circuit, and through the signal control unit, when the single cell or the battery pack exceeds a predetermined voltage value, the thermistor is heated and the fuse component is blown, thereby cutting off the charging circuit.

[0018] The battery pack of the present invention is used for electric machines such as mobile devices that do not require wires. That is, an electric machine is provided, which utilizes a battery pack of a secondary battery such as a lithium-ion battery, and has: a battery pack, which is formed by connecting one or more cells of a secondary battery; a battery pack, which has a protection circuit or a charging and discharging device for controlling the charging and discharging of the battery pack; and a machine body, which is detachably connected to the battery pack and is used to charge the battery pack or receive power supply from the battery pack for driving; the battery pack has: a signal control unit, which outputs a control signal according to the voltage of the cell or the battery pack; a first switching element and a second switching element, which are connected in parallel to the current circuit between the battery pack and the external terminal, and receive a signal from the signal control unit to perform on / off control; and a protection element, which has a built-in protection The fuse assembly and the thermistor are connected in parallel with the discharge circuit, and the operation of the thermistor is controlled by a third switch element connected to a signal control unit; the signal control unit disconnects the first switch element and connects the second switch element during charging, and connects the first switch element and disconnects the second switch element during discharging, thereby controlling the on / off of the charging circuit and the discharge circuit; the protection element is that when the value of the current of the charging circuit flowing through the second switch element exceeds a predetermined fuse current value, the fuse assembly is blown to cut off the charging circuit, and through the signal control unit, when the cell or the battery pack exceeds a predetermined voltage value, the thermistor is heated and the fuse assembly is blown, thereby cutting off the charging circuit.

[0019] According to another aspect of the present invention, a protection circuit is proposed, which protects a battery pack of a secondary battery such as a lithium-ion battery from overcharging and overheating, and comprises: a battery pack, which is composed of one or more connected cells; a signal control unit, which monitors the voltage of the cell or the battery pack and outputs a control signal based on its measured value; a switching control element, which is connected to the discharge circuit and the charging circuit between the battery pack and the external terminal of the battery pack, and receives a signal from the signal control unit to perform on / off control; and a protection element, which has a built-in fuse assembly and a thermistor, the fuse assembly is connected in parallel with the discharge circuit, and the operation of the thermistor is controlled by the switching element connected to the signal control unit.

[0020] Furthermore, the protection circuit with the switching control element is applied to a charging and discharging device. That is, a charging and discharging device is provided, which is a charging and discharging device for a battery pack of a secondary battery such as a lithium-ion battery having the switching control element, and comprises: a battery pack, which is formed by connecting one or more cells; a signal control unit, which outputs a control signal according to the voltage of the cell or the battery pack; a switching control element, which is connected to the discharge circuit and the charging circuit between the battery pack and the external terminal of the battery pack, and receives a signal from the signal control unit to perform on / off control; and a protection element, which has a built-in fuse component and a thermistor, the fuse component is connected in parallel with the discharge circuit, and the thermistor is connected in parallel with the discharge circuit. The action of the resistor is controlled by a switching element connected to a signal control unit; the switching control element can disconnect the discharge circuit and connect the charging circuit through the signal control unit during charging, and connect the discharge circuit and disconnect the charging circuit through the signal control unit during discharging, thereby controlling the on / off of the charging circuit and the discharge circuit, and the protection element has a fuse component, which is blown when the value of the current flowing through the charging circuit of the switching control element exceeds a predetermined fusing current value, or is blown by the heating caused by the power supply of the thermistor when the voltage of the single cell or the battery pack exceeds a predetermined voltage value.

[0021] The protection circuit and charging and discharging device including the switching control element can be used for a battery pack. That is, a battery pack is provided, which is a battery pack of secondary batteries such as lithium-ion batteries, and comprises: a battery pack, which is formed by connecting one or more secondary battery cells; a signal control unit, which outputs a control signal according to the voltage of the cell or the battery pack; a switching control element, which is connected to the discharge circuit and the charging circuit between the battery pack and the external terminal of the battery pack, and receives a signal from the signal control unit to perform on / off control; and a protection element, which has a built-in fuse component and a thermistor, the fuse component is connected in parallel with the discharge circuit, and the operation of the thermistor is controlled by the connection The switch element connected to the signal control unit controls the on / off control of the charging circuit and the discharging circuit by disconnecting the discharging circuit and connecting the charging circuit during charging, and connecting the discharging circuit and disconnecting the charging circuit during discharging. The protection element is that when the value of the current in the charging circuit flowing through the switching control element exceeds a predetermined fuse current value, the fuse component blows to cut off the charging circuit, and through the signal control unit, when the single cell or the battery pack exceeds a predetermined voltage value, the thermistor is heated and the fuse component is blown, thereby cutting off the charging circuit.

[0022] The battery pack of the present invention including a switching control element can be used for electric machines such as mobile devices that do not require wires. That is, an electric machine is provided, which utilizes a battery pack of a secondary battery such as a lithium-ion battery, and has: a battery pack, which is formed by connecting one or more cells of a secondary battery; a battery pack, which has a protection circuit or a charging and discharging device for controlling the charging and discharging of the battery pack; and a machine body, which is detachably connected to the battery pack and is used to charge the battery pack or receive power supply from the battery pack for driving; the battery pack has: a signal control unit, which outputs a control signal according to the voltage of the cell or the battery pack; a switching control element, which is connected to the discharge circuit and the charging circuit between the battery pack and the external terminal of the battery pack, and receives a signal from the signal control unit to perform on / off control; and a protection element , which has a built-in fuse component and a thermistor, the fuse component is connected in parallel with the discharge circuit, and the operation of the thermistor is controlled by a switch element connected to a signal control unit; the signal control unit disconnects the discharge circuit and connects the charging circuit during charging, and connects the discharge circuit and disconnects the charging circuit during discharging, thereby controlling the on / off of the charging circuit and the discharge circuit; the protection element is that when the value of the current of the charging circuit flowing through the switching control element exceeds a predetermined fuse current value, the fuse component is blown to cut off the charging circuit, and through the signal control unit, when the cell or the battery pack exceeds a predetermined voltage value, the thermistor is heated and the fuse component is blown, thereby cutting off the charging circuit.

[0023] (Effects of the Invention)

[0024] The present invention provides a protective device for a battery pack having a simpler structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is a diagram showing a protection circuit 10 according to the present invention.

[0026] Figure 2 2 is a diagram showing a protection circuit 20 according to the present invention.

[0027] Figure 3 1 is a diagram showing a protection circuit 30 according to the present invention.

[0028] Figure 4 1 is a diagram showing a protection circuit 40 according to the present invention.

[0029] Figure 5 It is a diagram showing a protection circuit 50 according to the first embodiment of the present invention.

[0030] Figure 6 It is a diagram showing a protection circuit 60 according to a second embodiment of the present invention.

[0031] Figure 7 It is a diagram showing a protection circuit 70 according to a third embodiment of the present invention.

[0032] Figure 8 It is a diagram showing a protection circuit 80 according to a fourth embodiment of the present invention.

[0033] Fig. 9 It is a diagram showing the buffering effect obtained by using the delay circuit of the present invention.

[0034] Fig.10 FIG. 1 is a diagram showing a protective circuit 100 obtained by modifying the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0035] like Figure 1 As shown, the protection circuit 10 of the present invention is a protection circuit for protecting a battery pack of a secondary battery such as a lithium-ion battery from overcharging and overheating, and includes: a battery pack 12, which is composed of more than one secondary battery cell 11 connected in series; a signal control unit 13, which outputs a control signal according to the voltage of the cell 11 or the battery pack 12; a first switch element 15-1 and a second switch element 15-2, which are connected in parallel to the current circuit between the battery pack 12 and the external terminal 14, and receive a signal from the signal control unit 13 to perform on / off control; and a protection element 16, which has a built-in fuse component 16-1 and a thermistor 16-2, the fuse component 16-1 is connected in parallel to the discharge circuit, and the action of the thermistor 16-2 is controlled by a third switch element 15-3 connected to the signal control unit 13. As shown in FIG. Figure 1As shown in FIG. 1 , the protection circuit 10 can control the switching of the charging and discharging circuits only through the signal control unit 13, thereby simplifying the circuit structure and reducing the risk of failure (error) of the control unit. Figure 8 The delay circuit 89 shown, which includes a resistor element 89 - 1 and a capacitor element 89 - 2 , can delay the applied voltage, thereby buffering an overshoot current such as an inrush current during switching.

[0036] The protection circuit 10 is applied to a battery pack charging and discharging device. That is, a charging and discharging device is provided, which is a charging and discharging device for a battery pack of a secondary battery such as a lithium-ion battery, and comprises: a battery pack 12, which is formed by connecting one or more cells 11 of a secondary battery in series; a signal control unit 13, which outputs a control signal according to the voltage of the cell 11 or the battery pack 12; a first switch element 15-1 and a second switch element 15-2, which are connected in parallel to a current circuit between the battery pack 12 and an external terminal 14, and receive a signal from the signal control unit 13 to perform on / off control; and a protection element 16, which has a built-in fuse component 16-1 and a thermistor 16-2, the fuse component 16-1 is connected in parallel to the discharge circuit, and the thermistor 16-2 is connected in parallel to the discharge circuit. The action of 6-2 is controlled by the third switch element 15-3 connected to the signal control unit 13; the signal control unit 13 can turn off the first switch element 15-1 and turn on the second switch element 15-2 during charging, and turn on the first switch element 15-1 and turn off the second switch element 15-2 during discharging, thereby controlling the on / off of the charging circuit and the discharging circuit. The protection element 16 has a fuse component 16-1, which blows when the current value of the charging circuit flowing through the second switch element 15-2 exceeds a predetermined fusing current value, or when the voltage of the single cell 11 or the battery pack 12 exceeds a predetermined voltage value, it blows through the heating caused by the power supply of the thermistor 16-2.

[0037] In the protection circuit or charging and discharging device, the second switch element 15-2 is disposed between the cell 11 or the battery pack 12 and the protection element 16. Alternatively, in another example of the protection circuit or the charging and discharging device of the present invention, the protection element 16 is disposed between the cell 11 or the battery pack 12 and the second switch element 15-2.

[0038] Furthermore, in the protection circuit or charging and discharging device of the present invention, the first switching element 15-1 is connected between the battery group 12 and the external terminal 14 of the battery pack, and includes a switching transistor, which receives a signal from the signal control unit 13 that outputs a control signal based on the voltage of the single cell 11 to perform on / off control. The second switching element 15-2 is connected in parallel with the first switching element 15-1, and includes a switching transistor that receives a signal from the signal control unit 13 to perform on / off control. The first switching element 15-1 and the second switching element 15-2 are configured so that the bias directions of the internal diodes in the switching transistors are opposite to each other. The signal control unit 13 implements the following on / off control, that is, the first switching element 15-1 is disconnected and the second switching element 15-2 is connected during charging, and the first switching element 15-1 is connected and the second switching element 15-2 is disconnected during discharging. For example, the first switch element 15-1 and the second switch element 15-2 may each include a field effect transistor. If the first switch element 15-1 and the second switch element 15-2 are configured such that the bias directions of the internal diodes in the field effect transistors are opposite to each other, the signal control unit 13 may perform the following on / off control, i.e., the first switch element 15-1 is turned off and the second switch element 15-2 is turned on during charging, and the first switch element 15-1 is turned on and the second switch element 15-2 is turned off during discharging.

[0039] The protection circuit 10 may also be Figure 2 The protective circuit 20 shown in the figure is modified. That is, it comprises: a battery pack 22, which is formed by connecting one or more cells 21 of secondary batteries in series; a signal control unit 23, which outputs a control signal according to the voltage of the cell 21 or the battery pack 22; a first switch element 25-1 and a second switch element 25-2, which are connected in parallel to the current circuit between the battery pack 22 and the external terminal 24, and receive the signal from the signal control unit 23 to perform on / off control; and a protective element 26, which has a built-in fuse component 26-1 and a thermistor 26-2, the fuse component 26-1 is connected in parallel to the discharge circuit, and the operation of the thermistor 26-2 is controlled by a third switch element 25-3 connected to the signal control unit 23; the signal control unit 23 can also branch its signal circuit and set an inverter element (inverting amplifier element) 27 in any signal circuit, and connect the gate of the first switch element 25-1 to one side of the branched signal circuit, and connect the gate of the second switch element 25-2 to the other side. In this case, one of the first switch element 25-1 and the second switch element 25-2 has an inverter element 27, so that one signal path can be shared. Figure 2 As shown, the switching of the charging and discharging circuits is controlled by a single signal from the signal control unit 23, thereby simplifying the circuit configuration and reducing the risk of errors in the control unit.

[0040] Furthermore, the protection circuit 10 of the present invention may also be Figure 3 The protection circuit 30 shown is generally modified, that is, it comprises: a battery pack 32, which is composed of more than one secondary battery cell 31 connected in series; a signal control unit 33, which outputs a control signal according to the voltage of the cell 31 or the battery pack 32; a first switch element 35-1 and a second switch element 35-2, which are connected in parallel to the current circuit between the battery pack 32 and the external terminal 34, and receive the signal from the signal control unit 33 to perform on / off control; and a protection element 36, which has a built-in fuse component 36-1 and a thermistor 36-2, the fuse component 36-1 is connected in parallel to the discharge circuit, and the operation of the thermistor 36-2 is controlled by a third switch element 35-3 connected to the signal control unit 33; the signal control unit 33 branches its signal circuit and sets an inverter element (inverting amplifier element) 37 in any signal circuit, and connects the gate of the first switch element 35-1 to one side of the branched signal circuit and the gate of the second switch element 35-2 to the other side. In this case, one of the first switch element 35-1 and the second switch element 35-2 has an inverter element 37, so that one signal circuit can be shared. The protection element 36 is arranged between the battery pack 32 and the first switch element 35-1, and cuts off the charging circuit when the thermistor 36-2 and the fuse assembly 36-1 exceed a predetermined melting temperature, or when the value of the current flowing through the fuse assembly 36-1 via the second switch element 35-2 exceeds a predetermined melting current value. The thermistor 36-2 is energized by the signal control unit 33 that outputs a control signal based on the voltage of the single cell 31 or the battery pack 32, thereby generating heat when the single cell 31 or the battery pack 32 exceeds a predetermined voltage value. The fuse assembly 36-1 is connected in parallel with the first switch element 35-1. Figure 3 As shown, the protection circuit 30 can control the switching of the charging and discharging circuits by a single signal from the signal control unit 33, thereby simplifying the circuit structure and reducing the risk of failure of the control unit.

[0041] The signal control unit 13 of the protection circuit or charging and discharging device of the present invention is to change the switching transistor constituting the first switching element 15-1 from being disconnected to being connected, and the switching transistor constituting the second switching element 15-2 from being connected to being disconnected, by means of a control signal output according to the voltage of the single cell 11 or the battery pack 12 when the voltage of the single cell 11 or the battery pack 12 exceeds a predetermined voltage value. When the voltage of the single cell 11 or the battery pack 12 is less than the predetermined voltage value, the control signal of the signal control unit 13 is used to change the switching transistor constituting the first switching element 15-1 from being connected to being disconnected, and the switching transistor constituting the second switching element 15-2 from being disconnected to being connected.

[0042] The first switching element 15-1 of the protection circuit or charging and discharging device of the present invention includes a switching transistor, which is connected to the discharge circuit in a manner that the bias direction of the internal diode becomes forward relative to the discharge direction, and the second switching element 15-2 includes a switching transistor, which is connected to the charging circuit in a manner that the bias direction of the internal diode becomes forward relative to the charging direction.

[0043] The protection circuit or charging and discharging device of the present invention can be set as needed. Figure 8 The delay circuit 89 shown, which includes a resistor element 89 - 1 and a capacitor element 89 - 2 , can delay the applied voltage, thereby buffering an overshoot current such as an inrush current during switching.

[0044] The protection circuit or charging and discharging device of the present invention is applied to a battery pack. That is, a battery pack is provided, which is a battery pack of a secondary battery such as a lithium-ion battery, and comprises: a battery pack 12, which is composed of one or more secondary battery cells 11 connected in series; a signal control unit 13, which outputs a control signal according to the voltage of the cell 11 or the battery pack 12; a first switch element 15-1 and a second switch element 15-2, which are connected in parallel to the current circuit between the battery pack 12 and the external terminal 14, and receive a signal from the signal control unit to perform on / off control; and a protection element 16, which has a built-in fuse component 16-1 and a thermistor 16-2, the fuse component 16-1 is connected in parallel to the discharge circuit, and the action of the thermistor 16-2 is controlled by the signal control unit connected to the signal control unit. The third switch element 15-3 of the control unit 13 is controlled; the signal control unit 13 turns off the first switch element 15-1 and turns on the second switch element 15-2 during charging, and turns on the first switch element 15-1 and turns off the second switch element 15-2 during discharging, thereby controlling the on / off of the charging circuit and the discharging circuit. The protection element 16 is that when the value of the current of the charging circuit flowing through the second switch element 15-2 exceeds a predetermined fuse current value, the fuse component 16-1 melts and cuts off the charging circuit, and through the signal control unit 13, when the cell 11 or the battery pack 12 exceeds a predetermined voltage value, the thermistor 16-2 is heated and the fuse component 16-1 is melted, thereby cutting off the charging circuit.

[0045] The battery pack of the present invention is used for electric machines such as mobile devices that do not require wires. That is, an electric machine is provided, which utilizes a battery pack of a secondary battery such as a lithium-ion battery, and has: a battery pack 12, which is composed of one or more cells 11 of a secondary battery connected in series; a battery pack, which has a protection circuit or a charging and discharging device for controlling the charging and discharging of the battery pack 12; and a machine body, which is detachably connected to the battery pack and is used to charge the battery pack or receive power supply from the battery pack for driving; the battery pack has: a signal control unit 13, which outputs a control signal according to the voltage of the cell 11 or the battery pack 12; a first switching element 15-1 and a second switching element 15-2, which are connected in parallel to the current circuit between the battery pack 12 and the external terminal 14, and receive the signal from the signal control unit 13 to perform on / off control; and a protection element 16, which has a built-in fuse component 16-1 and a thermistor 16-2, the fuse assembly 16-1 is connected in parallel with the discharge circuit, and the operation of the thermistor 16-2 is controlled by the third switch element 15-3 connected to the signal control unit 13; the signal control unit 13 turns off the first switch element 15-1 and turns on the second switch element 15-2 during charging, and turns on the first switch element 15-1 and turns off the second switch element 15-2 during discharging, thereby controlling the on / off of the charging circuit and the discharge circuit, and the protection element 16 is that when the value of the current of the charging circuit flowing through the second switch element 15-2 exceeds a predetermined fusing current value, the fuse assembly 16-1 melts and cuts off the charging circuit, and through the signal control unit 13, when the cell 11 or the battery pack 12 exceeds a predetermined voltage value, the thermistor 16-2 is heated and the fuse assembly 16-1 is melted, thereby cutting off the charging circuit.

[0046] like Figure 4 As shown, the protection circuit 40 of the present invention is a protection circuit for protecting a battery pack of a secondary battery such as a lithium-ion battery from overcharging and overheating, and comprises: a battery pack 42, which is composed of one or more cells 41 connected in series; a signal control unit 43, which monitors the voltage of the cell 41 or the battery pack 42 and outputs a control signal according to its measured value; a switching control element 45, which is connected to the discharge circuit and the charging circuit between the battery pack 42 and the external terminal 44 of the battery pack, and receives a signal from the signal control unit 43 to perform on / off control; and a protection element 46, which has a built-in fuse component 46-1 and a thermistor 46-2, the fuse component 46-1 is connected in parallel with the discharge circuit, and the action of the thermistor 46-2 is controlled by a switching element 48 connected to the signal control unit 43. As shown in FIG. Figure 4 As shown in FIG. 1 , the protection circuit 40 can control the switching of the charging and discharging circuits by a single signal from the signal control unit 43, thereby simplifying the circuit configuration and eliminating the risk of errors caused by the switching control unit. Figure 8 The delay circuit 89 shown, which includes a resistor element 89 - 1 and a capacitor element 89 - 2 , can delay the applied voltage, thereby buffering an overshoot current such as an inrush current during switching.

[0047] Furthermore, the protection circuit with the switching control element is applied to the charging and discharging device. That is, the charging and discharging device with the switching control element of the present invention comprises: a battery pack 42, which is composed of one or more monomers 41 connected in series; a signal control unit 43, which outputs a control signal according to the voltage of the monomer 41 or the battery pack 42; a switching control element 45, which is connected to the discharge circuit and the charging circuit between the battery pack 42 and the external terminal 44 of the battery pack, and receives the signal from the signal control unit 43 to perform on / off control; and a protection element 46, which has a built-in fuse component 46-1 and a thermistor 46-2, the fuse component 46-1 is connected in parallel with the discharge circuit, and the operation of the thermistor 46-2 is controlled by the connection to The switching element 48 of the signal control unit 43 controls the switching control element 45. The switching control element 45 can disconnect the discharge circuit and connect the charging circuit through the signal control unit 43 during charging, and connect the discharge circuit and disconnect the charging circuit through the signal control unit 43 during discharging, thereby controlling the on / off of the charging circuit and the discharge circuit. The protection element 46 has a fuse component 46-1, which is blown when the value of the current flowing through the charging circuit of the switching control element 45 exceeds a predetermined fusing current value, or is blown by the power-on heating of the thermistor 46-2 when the voltage of the single cell 41 or the battery pack 42 exceeds a predetermined voltage value.

[0048] The switching control element 45 of the present invention includes a selector, a switch controller, a complementary metal oxide semiconductor (CMOS) transistor, a MOSFET, an IGBT, a FET or other switching transistor, or a protection circuit module including the switching element. The switching element 48 includes a MOSFET, an IGBT, a FET or other switching element, or a protection circuit module including the switching element.

[0049] In the protection circuit or charging and discharging device including the switching control element 45 of the present invention, the protection element 46 is arranged on the charging circuit between the cell 41 or the battery pack 42 and the switching control element 45. Moreover, although not shown in the figure, in another example of the protection circuit or charging and discharging device including the switching control element, the protection element 46 may also be arranged between the switching control element 45 and the external terminal 44 of the battery pack.

[0050] The protection circuit and charging and discharging device including the switching control element can be used for a battery pack. That is, the battery pack with the switching control element of the present invention is a battery pack of a secondary battery such as a lithium-ion battery, and comprises: a battery pack 42, which is composed of one or more cells 41 of the secondary battery connected in series; a signal control unit 43, which outputs a control signal according to the voltage of the cell 41 or the battery pack 42; a switching control element 45, which is connected to the discharge circuit and the charging circuit between the battery pack 42 and the external terminal 44 of the battery pack, and receives a signal from the signal control unit 43 to perform on / off control; and a protection element 46, which has a built-in fuse component 46-1 and a thermistor 46-2, the fuse component 46-1 is connected in parallel with the discharge circuit, and the thermistor 46-2 is connected in parallel with the thermistor 46-1. The action of 6-2 is controlled by a switch element 48 connected to a signal control unit 43; the signal control unit 43 disconnects the discharge circuit and connects the charging circuit during charging, and connects the discharge circuit and disconnects the charging circuit during discharging, thereby controlling the on / off of the charging circuit and the discharge circuit, and the protection element 46 disconnects the charging circuit by causing the fuse component 46-1 to melt when the current value of the charging circuit flowing through the switching control element 45 exceeds a predetermined fuse current value, and through the signal control unit 43, when the cell 41 or the battery pack 42 exceeds a predetermined voltage value, the thermistor 46-2 is heated and the fuse component 46-1 is melted, thereby disconnecting the charging circuit.

[0051] A battery pack including a switching control element 45 can be used for electric machines such as mobile devices that do not require wires. That is, the electric machine with a switching control element of the present invention is a battery pack that uses secondary batteries such as lithium-ion batteries, and has: a battery pack 42, which is composed of more than one secondary battery cell 41 connected in series; a battery pack, which has a protection circuit or a charging and discharging device that controls the charging and discharging of the battery pack 42; and a machine body, which is detachably connected to the battery pack and is used to charge the battery pack or receive power supply from the battery pack to drive; the battery pack has: a signal control unit 43, which outputs a control signal according to the voltage of the cell 41 or the battery pack 42; a switching control element 45, which is connected to the discharge circuit and the charging circuit between the battery pack 42 and the external terminal 44 of the battery pack, and receives the signal from the signal control unit 43 to perform on / off control; and a protection element 46, which has a built-in protection The fuse assembly 46-1 and the thermistor 46-2 are connected in parallel with the discharge circuit, and the operation of the thermistor 46-2 is controlled by a switch element 48 connected to a signal control unit 43; the signal control unit 43 disconnects the discharge circuit and connects the charging circuit during charging, and connects the discharge circuit and disconnects the charging circuit during discharging, thereby controlling the on / off of the charging circuit and the discharge circuit, and the protection element 46 is that when the value of the current of the charging circuit flowing through the switching control element 45 exceeds a predetermined fuse current value, the fuse assembly 46-1 is blown to cut off the charging circuit, and through the signal control unit 43, when the cell 41 or the battery pack 42 exceeds a predetermined voltage value, the thermistor 46-2 is heated and the fuse assembly 46-1 is blown, thereby cutting off the charging circuit.

[0052] [Example]

[0053] like Figure 5As shown, the protection circuit 50 of Example 1 comprises: a battery pack 52, which is composed of four cells 51 of lithium-ion batteries connected in series; a signal control unit 53, which outputs a control signal according to the voltage of the cell 51 or the battery pack 52; a first switch element 55-1 and a second switch element 55-2, which are connected in parallel in the current circuit between the battery pack 52 and the external terminal 54, receive the signal from the signal control unit 53 to perform on / off control, and each includes an N-channel MOSFET; and a protection element 56, which has a built-in fuse component 56-1 including a fusible metal material and a thermistor 56-2 including a film resistor, the fuse component 56-1 is connected in parallel with the discharge circuit, and the operation of the thermistor 56-2 is controlled by a third switch element 55-3 including an N-channel MOSFET connected to the signal control unit 53. The protection circuit 50 is applied to a charging and discharging device of a battery pack. The signal control unit 53 controls the on / off of the charging circuit and the discharging circuit by disconnecting the first switch element 55-1 and connecting the second switch element 55-2 during charging, and connecting the first switch element 55-1 and disconnecting the second switch element 55-2 during discharging.

[0054] like Figure 6As shown, the protection circuit 60 of the second embodiment comprises: a battery pack 62, which is composed of four cells 61 of lithium-ion batteries connected in series; a signal control unit 63, which outputs a control signal according to the voltage of the cell 61 or the battery pack 62; a first switch element 65-1 and a second switch element 65-2, which are connected in parallel in the current circuit between the battery pack 62 and the external terminal 64, receive the signal from the signal control unit 63 to perform on / off control, and each includes an N-channel MOSFET; and a protection element 66, which has a built-in fuse component 66-1 including a fusible metal material and a thermistor 66-2 including a film resistor, the fuse component 66-1 is connected in parallel with the discharge circuit, and the operation of the thermistor 66-2 is controlled by a third switch element 65-3 including an N-channel MOSFET connected to the signal control unit 63. The protection circuit 60 is applied to a charging and discharging device of a battery pack. The signal control unit 63 branches its signal circuit, connects the gate of the first switch element 65-1 on one side, and connects the gate of the second switch element 65-2 on the other side. The gate of the second switch element 65-2 is connected to the signal circuit of the signal control unit 63 via the inverter element 67. The gate of the first switch element 65-1 is connected to the signal control unit 63 without the inverter element 67. Since the second switch element 65-2 has the inverter element 67, it can share the signal circuit with the first switch element 65-1. Furthermore, in the second embodiment, the inverter element 67 is connected to one side of the second switch element 65-2, but the inverter element 67 only needs to be set in either the first or second switch element, and can also be appropriately configured on the side of the first switch element 65-1 instead of being configured on the side of the second switch element 65-2.

[0055] like Figure 7As shown, the protection circuit 70 of Example 3 comprises: a battery pack 72, which is composed of four cells 71 of lithium-ion batteries connected in series; a signal control unit 73, which monitors the voltage of the cell 71 or the battery pack 72 and outputs a control signal based on its measured value; a switching control element 75, which is connected to the discharge circuit and the charging circuit between the battery pack 72 and the external terminal 74 of the battery pack, receives the signal from the signal control unit 73 to perform on / off control, and includes a CMOS transistor with an inverter (inverting amplifier); and a protection element 76, which has a built-in fuse component 76-1 including a fusible metal material and a thermistor 76-2 including a film resistor, the fuse component 76-1 is connected in parallel with the discharge circuit, and the operation of the thermistor 76-2 is controlled by a switching element 78 including an N-channel MOSFET connected to the signal control unit 73. The protection circuit 70 is applied to the charging and discharging device of the battery pack, the signal control unit 73 is connected to the input end (IN) of the switching control element 75, the discharge circuit is connected to the drain of the switching control element 75, and the charging circuit is connected to the source of the switching control element 75 via the fuse component 76-1 of the protection element.

[0056] like Figure 8 As shown, the protection circuit 80 of the fourth embodiment comprises: a battery pack 82, which is composed of four cells 81 of lithium-ion batteries connected in series; a signal control unit 83, which outputs a control signal according to the voltage of the cell 81 or the battery pack 82; a first switch element 85-1 and a second switch element 85-2, which are connected in parallel in a current circuit between the battery pack 82 and an external terminal 84, receive a signal from the signal control unit 83 to perform on / off control, and include an N-channel MOSFET; a protection element 8 6, which has a built-in fuse component 86-1 including a fusible metal material and a thermistor 86-2 including a film resistor, the fuse component 86-1 is connected in parallel with the discharge circuit, and the operation of the thermistor 86-2 is controlled by a third switch element 85-3 including an N-channel MOSFET connected to the signal control unit 83; and a delay circuit 89, which includes a resistor element 89-1 connected in series with the battery pack 82 and a capacitor 89-2 connected to the resistor element 89-1 and connected in parallel with the battery pack 82. The protection circuit 80 can delay the application of voltage through the delay circuit 89, thereby buffering the inrush current generated in units of several μ seconds during switching, and is applied to a charging and discharging device of a battery pack. The signal control unit 83 can turn off the first switch element 85-1 and turn on the second switch element 85-2 during charging, and turn on the first switch element 85-1 and turn off the second switch element 85-2 during discharging, thereby controlling the on / off of the charging circuit and the discharging circuit. (Refer to Fig. 9 )

[0057] Furthermore, the protection circuit 80 of the fourth embodiment may also be Fig.10 The protective circuit 100 shown in the figure is modified. That is, it comprises: a battery pack 102, which is composed of one or more cells 101 of secondary batteries connected in series; a signal control unit 103, which outputs a control signal according to the voltage of the cell 101 or the battery pack 102; a protective element 106, which has a built-in fuse component 106-1 and a thermistor 106-2, the fuse component 106-1 is connected in series with a charge and discharge circuit including one path, and the operation of the thermistor 106-2 is controlled by a switch element 105 connected to the signal control unit 103; and a delay circuit 109, which includes a resistor element 109 connected in series with the battery pack 102. -1 and a capacitor element 109-2 connected to the resistor element 109-1 and connected in parallel to the battery pack 102; the protection circuit 100 delays the application of voltage through the delay circuit 89 to buffer the inrush current during switching, and when the value of the current flowing through the charging and discharging circuit exceeds a predetermined fuse current value, the fuse component 106-1 melts to cut off the charging and discharging circuit, and through the signal control unit 103, when the cell 101 or the battery pack 102 exceeds a predetermined voltage value, the thermistor 106-2 is heated and the fuse component 106-1 is melted, thereby cutting off the charging and discharging circuit.

[0058] The switch element of the protection circuit 100 may also include a switch transistor or a protection circuit module including the switch transistor.

[0059] The switch element of the protection circuit 100 may also include a FET or a protection circuit module including the FET.

[0060] The protection circuit 100 may be applied to a battery pack.

[0061] That is, it can also be a battery pack, which is a battery pack of secondary batteries such as lithium-ion batteries, and comprises: a battery pack, which is composed of more than one secondary battery cells connected in series; a signal control unit, which outputs a control signal according to the voltage of the cell or the battery pack; a protection element, which has a built-in fuse component and a thermistor, the fuse component is connected in series with a charge and discharge circuit, and the operation of the thermistor is controlled by a switch element connected to the signal control unit; and a delay circuit, which includes a resistor element connected to the battery pack and a capacitor element connected to the resistor element and connected to the battery pack; and the protection circuit is to delay the application of voltage through the delay circuit to buffer the inrush current during switching, and when the value of the current flowing through the charge and discharge circuit exceeds a predetermined fuse current value, the fuse component is melted to cut off the charge and discharge circuit, and through the signal control unit, when the cell or the battery pack exceeds a predetermined voltage value, the thermistor is heated and the fuse component is melted, thereby cutting off the charge and discharge circuit.

[0062] The configuration of the present invention can achieve simplification of the protection device, particularly focusing on overcharge protection, and can contribute to cost reduction of the battery pack and the protection circuit.

[0063] (Industrial Applicability)

[0064] The present invention can be used in a protection circuit of an electric or electronic device using a protection element provided with a thermistor and a fuse assembly, and can be used in particular in a protection device for a secondary battery such as a battery pack.

[0065] Description of Reference Numerals

[0066] 10, 20, 30, 40, 50, 60, 70, 80, 100: protection circuit

[0067] 11, 21, 31, 41, 51, 61, 71, 81, 101: Single

[0068] 12, 22, 32, 42, 52, 62, 72, 82, 102: Battery pack

[0069] 13, 23, 33, 43, 53, 63, 73, 83, 103: Signal control unit

[0070] 14, 24, 34, 44, 54, 64, 74, 84, 104: external terminals

[0071] 15-1, 25-1, 35-1, 55-1, 65-1, 85-1: first switching element

[0072] 15-2, 25-2, 35-2, 55-2, 65-2, 85-2: second switching element

[0073] 15-3, 25-3, 35-3, 55-3, 65-3, 85-3: third switching element

[0074] 16, 26, 36, 46, 56, 66, 76, 86, 106: protection elements

[0075] 16-1, 26-1, 36-1, 46-1, 56-1, 66-1, 76-1, 86-1, 106-1: Fuse assembly

[0076] 16-2, 26-2, 36-2, 46-2, 56-2, 66-2, 76-2, 86-2, 106-2: Thermistor

[0077] 27, 37, 67: Inverter components

[0078] 45, 75: Switching control elements

[0079] 48, 78, 105: Switching elements

[0080] 89, 109: Delay circuit

[0081] 89-1, 109-1: Resistor element

[0082] 89-2, 109-2: Capacitor elements.

Claims

1. A protection circuit that protects a lithium-ion battery pack from overcharging and overheating, and has: A battery pack, which is formed by connecting more than one monomer; a signal control unit, which monitors the voltage of the monomer or the battery pack and outputs a control signal according to the measured value; a switching control element, which is connected to the discharge circuit and the charging circuit between the battery pack and the external terminal of the battery pack, and receives the signal from the signal control unit to perform on / off control; and a protection element, which has a built-in fuse component and a thermistor, the fuse component is connected in parallel with the discharge circuit, and the operation of the thermistor is controlled by the switch element connected to the signal control unit, The signal control unit During charging, the discharge circuit is disconnected and the charging circuit is connected, During discharge, the discharge circuit is turned on and the charging circuit is turned off, and the charging circuit and the discharge circuit are controlled to be on / off, and The protection element When the value of the current of the charging circuit flowing through the switching control element exceeds a predetermined fuse current value, the fuse assembly is melted to cut off the charging circuit, and when the voltage of the cell or the battery pack exceeds a predetermined voltage value, the thermistor is heated by the signal control unit to melt the fuse assembly, thereby cutting off the charging circuit. The switching control element includes a switch element with an inverter or a protection circuit module including the switch element with an inverter.

2. The protection circuit according to claim 1, wherein: The switching element with an inverter includes a switching element selected from the group consisting of a selector, a switch controller, a CMOS transistor, and a FET.

3. The protection circuit according to claim 1 or 2, wherein: The protection circuit is further provided with a delay circuit including a resistance element and a capacitor element.

4. A charging and discharging device, which is a charging and discharging device for a lithium-ion battery pack, and comprises: A battery pack, which is formed by connecting more than one monomer; a signal control unit, which outputs a control signal according to the voltage of the monomer or the battery pack; a switching control element, which is connected to the discharge circuit and the charging circuit between the battery pack and the external terminal of the battery pack, and receives the signal from the signal control unit to perform on / off control; and a protection element, which has a built-in fuse component and a thermistor, the fuse component is connected in parallel with the discharge circuit, and the action of the thermistor is controlled by the switch element connected to the signal control unit; The switching control element can disconnect the discharge circuit and connect the charging circuit through the signal control unit during charging. During discharge, the signal control unit turns on the discharge circuit and turns off the charge circuit, thereby controlling the charge circuit and the discharge circuit to be turned on and off, and The protection element has the fuse assembly, and the fuse assembly is blown when the value of the current flowing through the charging circuit of the switching control element exceeds a predetermined fuse current value. Alternatively, when the voltage of the cell or the battery pack exceeds a predetermined voltage value, the thermistor is energized and heated to cause the thermistor to fuse. The switching control element includes a switch element with an inverter or a protection circuit module including the switch element with an inverter.

5. The charge and discharge device according to claim 4, wherein: The switching element with an inverter includes a switching element selected from the group consisting of a selector, a switch controller, a CMOS transistor, and a FET.

6. The charge and discharge device according to claim 4 or 5, wherein: The charging and discharging device is further provided with a delay circuit including a resistance element and a capacitor element.

7. A battery pack, which is a lithium-ion battery pack and comprises: A battery pack, which is formed by connecting one or more lithium-ion battery cells; a signal control unit, which outputs a control signal according to the voltage of the cell or the battery pack; a switching control element, which is connected to the discharge circuit and the charging circuit between the battery pack and the external terminal of the battery pack, and receives a signal from the signal control unit to perform on / off control; and a protection element, which has a built-in fuse component and a thermistor, the fuse component is connected in parallel with the discharge circuit, and the operation of the thermistor is controlled by the switch element connected to the signal control unit; The signal control unit During charging, the discharge circuit is disconnected and the charging circuit is connected, During discharge, the discharge circuit is turned on and the charging circuit is turned off, and the charging circuit and the discharge circuit are controlled to be on / off, and The protection element When the value of the current of the charging circuit flowing through the switching control element exceeds a predetermined fuse current value, the fuse assembly is melted to cut off the charging circuit, and when the voltage of the cell or the battery pack exceeds a predetermined voltage value, the thermistor is heated by the signal control unit to melt the fuse assembly, thereby cutting off the charging circuit. The switching control element includes a switch element with an inverter or a protection circuit module including the switch element with an inverter.

8. The battery pack according to claim 7, wherein: The switching element with an inverter includes a switching element selected from the group consisting of a selector, a switch controller, a CMOS transistor, and a FET.

9. The battery pack according to claim 7 or 8, wherein: The battery pack is further provided with a delay circuit including a resistance element and a capacitor element.

10. An electric machine using a battery pack of a lithium-ion battery and comprising: A battery pack, which is formed by connecting one or more lithium-ion battery cells; a battery pack having a protection circuit or a charging and discharging device for controlling the charging and discharging of the battery pack; and a machine body, which is detachably connected to the battery pack and is driven by charging the battery pack or receiving power supply from the battery pack; The battery pack has: A signal control unit that outputs a control signal according to the voltage of a single cell or a battery pack; a switching control element that is connected to a discharge circuit and a charging circuit between the battery pack and an external terminal of the battery pack and receives a signal from the signal control unit to perform on / off control; and a protection element that has a built-in fuse assembly and a thermistor, the fuse assembly is connected in parallel to the discharge circuit, and the operation of the thermistor is controlled by a switching element connected to the signal control unit; The signal control unit During charging, the discharge circuit is disconnected and the charging circuit is connected, During discharge, the discharge circuit is turned on and the charging circuit is turned off, and the charging circuit and the discharge circuit are controlled to be on / off, and The protection element When the value of the current of the charging circuit flowing through the switching control element exceeds a predetermined fuse current value, the fuse assembly is melted to cut off the charging circuit, and when the voltage of the cell or the battery pack exceeds a predetermined voltage value, the thermistor is heated by the signal control unit to melt the fuse assembly, thereby cutting off the charging circuit. The switching control element includes a switch element with an inverter or a protection circuit module including the switch element with an inverter.

11. The electric machine according to claim 10, wherein: The switching element with an inverter includes a switching element selected from the group consisting of a selector, a switch controller, a CMOS transistor, and a FET.

12. The electric machine according to claim 10 or 11, wherein: The electric machine is further provided with a delay circuit including a resistance element and a capacitor element.

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