Power supply with a battery unit

Abstract

The present invention blocks a current by reliably fusing a fuse element of an SCP with a simple circuit configuration.　This power supply comprising a battery unit performs, with a control circuit 7, ON / OFF control of a switch 6 which connects, to a battery unit 1, an SCP 3 that is connected in series to the battery unit 1 and blocks charge / discharge current in an abnormal state. The battery unit 1 comprises a plurality of battery cells 2 connected in series, wherein: the SCP 3 includes a fuse element 4 connected in series to an output side of the battery unit 1, and a heater 5 for fusing the fuse element 4; the switch 6 comprises a plurality of switching elements 10 formed by connecting one terminal to the heater 5 and the other terminal to a different voltage terminal 11 of the battery unit 1; the control circuit 7 selects, with a selection circuit 9, the switching elements 10 switched to an ON state by a detection voltage of a voltage detection circuit 8; and the ON-state switching elements 10 connect the battery unit 1 to the heater 5 to fuse the fuse element 4.

Description

Technical Field

[0001] The present invention relates to a power supply in which an SCP (Self-Control Protector) is connected in series with a battery unit.

Background Art

[0002] A power supply including a battery unit has an SCP connected to the output side, and the SCP cuts off the current during an abnormality. The SCP includes a fuse element connected in series with the battery unit and a heater that heats and melts the fuse element by Joule heat. The heater is disposed close to the fuse element in a thermally coupled state and is connected to the battery unit via a switch to generate heat by Joule heat. The switch is switched to the on state during an abnormality in the battery or the load side. The on-state switch supplies power from the battery unit to the heater to heat the heater. Although the heater generates heat when power is supplied from the battery unit, if the power supplied from the battery unit to the heater is too small, the amount of heat generated by the Joule heat of the heater is small, and the fuse element cannot be heated to the melting temperature and melted. On the contrary, if the power supplied from the battery unit is too large, the heater burns out and the fuse element cannot be heated and melted. In order for this protection element to surely melt the fuse element within a set range of the power supplied to the heater during an abnormality and cut off the current output, it is required to set the power supplied from the battery unit to the heater within a set range.

[0003] A battery unit in which a plurality of battery cells are connected in series is charged and its voltage rises, and discharged and its voltage drops, resulting in voltage fluctuations. In particular, a lithium-ion secondary battery, which has a large charge-discharge capacity and is diversified for various applications, has a large voltage fluctuation with respect to the remaining capacity. The voltage changes significantly between a battery unit that is fully charged and has a remaining capacity close to 100% and a battery unit that is discharged to a remaining capacity close to 0%. Therefore, there is a problem that the power supply to the heater changes significantly when the battery unit is connected to the heater.

[0004] For example, an SCP (SFK-5045x) that sets the operating voltage of a heater for fusing a fuse element to 43.7 to 62 V is commercially available. When this SCP is connected to a battery unit in which 14 battery cells are connected in series and supplies voltage from the battery unit to the heater, the voltage of the battery cells within the operating voltage range of the heater becomes 3.15 to 4.35 V. Therefore, when the cell voltage of the battery unit becomes 3.15 V or less, the SCP cannot be fused, and in a state where the cell voltage drops to 3 V or less, the SCP cannot be fused to prohibit charge and discharge of the battery pack.

[0005] To prevent the above disadvantages, a power supply that supplies power from a battery unit to a heater via a constant current circuit has been developed. (Patent Document 1)

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The power supply that supplies power from the battery unit to the heater of the SCP via a constant current circuit can heat the heater with a constant current regardless of the voltage fluctuation of the battery unit. Therefore, even if the voltage of the battery unit changes, the heating amount of the heater can be kept constant. This is because the Joule heat that heats the heater is specified by the product of the square of the current and the electrical resistance of the heater. Therefore, the power supply that energizes the heater from the battery unit via the constant current circuit can heat the heater in a preferable state and melt the fuse element. However, the constant current circuit reduces the voltage of the battery unit by the voltage drop of the internal resistance of the semiconductor element and maintains the output voltage at a constant value. Therefore, the internal resistance of a circuit that reduces the voltage, such as a semiconductor element such as a transistor or FET, generates heat due to Joule heat. The heat generation of the semiconductor element increases in proportion to the product of the square of the current and the internal resistance. However, in a general SCP, the heater current required to melt the fuse element is as large as about several amperes. Furthermore, since the voltage of the battery unit is reduced by the internal resistance, even in a short-time drive until the fuse element is melted, considering heat generation, the circuit scale of the constant current circuit becomes large, and there is also a drawback that the circuit configuration becomes complicated.

[0008] The present invention has been developed for the purpose of further eliminating the above drawbacks. An important object of the present invention is to provide a power supply including a battery unit that can surely melt the fuse element of the SCP with a simple circuit configuration and cut off the current.

Means for Solving the Problem

[0009] A power supply comprising a battery unit according to an aspect of the present invention includes a battery unit, an SCP (Self-Control Protector) connected in series with the battery unit to cut off the charge and discharge current in an abnormal state, a switch connecting the SCP to the battery unit, and a control circuit for on / off controlling the switch. The battery unit includes a plurality of battery cells connected in series with each other. The SCP includes a fuse element connected in series on the output side of the battery unit, and a heater connected to the battery unit that generates heat by Joule heat to melt the fuse element. The switch includes a plurality of switching elements having one terminal connected to the heater and the other terminal connected to a plurality of different voltage terminals having different voltages of the battery unit. The control circuit includes a voltage detection circuit for detecting the voltage of the battery unit or the battery cell, and a selection circuit for selecting a switching element to be switched to the on state based on the detected voltage of the voltage detection circuit. In an abnormal state, the selection circuit selects a switching element to be switched to the on state, and the on-state switching element connects the battery unit to the heater to melt the fuse element.

Effect of the Invention

[0010] The power supply including the above battery unit can surely melt the fuse element of the SCP with a simple circuit configuration to cut off the current.

Brief Description of the Drawings

[0011]

Figure 1

Mode for Carrying Out the Invention

[0012] A power supply including a battery unit according to an embodiment of the present invention includes a battery unit, an SCP (Self-Control Protector) connected in series with the battery unit to cut off a charge / discharge current in an abnormal state, a switch connecting the SCP to the battery unit, and a control circuit for controlling the on / off state of the switch. The battery unit includes a plurality of battery cells connected in series with each other. The SCP includes a fuse element connected in series on the output side of the battery unit, and a heater connected to the battery unit and generating heat by Joule heat to melt the fuse element. The switch includes a plurality of switching elements having one terminal connected to the heater and the other terminal connected to a plurality of different voltage terminals having different voltages of the battery unit. The control circuit includes a voltage detection circuit for detecting the voltage of the battery unit or the battery cell, and a selection circuit for selecting a switching element to be switched to the on state based on the detected voltage of the voltage detection circuit. In an abnormal state, the selection circuit selects a switching element to be switched to the on state, and the on-state switching element connects the battery unit to the heater to melt the fuse element.

[0013] The above power supply selects different voltage terminals for connecting the heater to the battery unit in response to voltage changes in the battery unit or battery cells. Therefore, even when the voltage of the battery unit or battery cells fluctuates, the voltage supplied from the battery unit to the heater is within the set range, and the heater can heat the fuse element to surely blow the fuse in the battery unit. Since the battery unit connects a plurality of battery cells in series, the voltage at the connection point where the battery cells are connected in series is an integer multiple of the cell voltage from the minus side to the plus side of the battery unit. Although the cell voltage changes with the remaining capacity and is not constant, the voltage of the different voltage terminals gradually increases from the minus side towards the connection point on the plus side. For example, in a battery unit with 10 battery cells connected in series, the total voltage is 10 times the cell voltage, and the voltage of the different voltage terminal at the middle connection point is 5 times. Therefore, when the cell voltage drops to 1 / 2 of the maximum voltage, the total voltage of the battery unit is supplied to the heater through the switching element, and when the cell voltage rises to the maximum voltage, the heater can be energized from the switching element connected to the different voltage terminal at the middle connection point to supply the same voltage to the heater.

[0014] The above power supply uses, for example, an SCP (SFK3045x) with an operating voltage of the heater for blowing the fuse element set to 22.3 - 31.5V. The first to third switching elements are selected to supply voltage to the heater from 7 series-connected battery cells, 9 series-connected battery cells, and 12 series-connected battery cells according to the voltage of the battery cells, and are turned on to set the operating voltage of the heater within the above range to blow the fuse element.

[0015] The first switching element supplies voltage to the heater from 7 series-connected battery cells within the range where the cell voltage is 3.2 - 4.35V. With the above cell voltage, the supply voltage of the heater is 22.4 - 30.45V. The second switching element supplies voltage to the heater from 9 series-connected battery cells within the range where the cell voltage is 2.5 - 3.5V. With the above cell voltage, the supply voltage of the heater is 22.5 - 31.5V. The third switching element supplies voltage from 12 series battery cells to the heater within a range where the cell voltage is 1.9 to 2.6 V. With the above cell voltage, the supply voltage to the heater becomes 22.8 to 31.2 V.

[0016] The above power supply supplies voltage from the battery unit to the heater of the SCP via the first to third switching elements. However, a power supply device having four sets of switching elements supplies voltage from 14 series battery cells to the heater in a state where the cell voltage drops to 1.6 to 2.2 V, and sets the supply voltage to the heater to 22.4 to 30.8 V, enabling it to be set to the specified operating voltage.

[0017] The power supply provided with the battery unit of another embodiment of the present invention includes a detection unit for detecting an abnormal state. In a state where the detection unit detects an abnormal state, the switching element is turned on to fuse the fuse element.

[0018] The power supply provided with the battery unit of another embodiment of the present invention includes an AFE (Analog Front End) for detecting the voltage of each battery cell and an MPU (Microprocessor Unit) for detecting the total voltage of the battery unit. The cell voltage detected by the AFE and the total voltage of the battery unit detected by the MPU are compared with a threshold value to determine an abnormality.

[0019] The power supply provided with the battery unit of another embodiment of the present invention has an overcharge detection unit for detecting overcharge of the battery unit. The overcharge detection unit detects overcharge of the battery unit and fuses the fuse element of the SCP.

[0020] The above power supply directly controls the switching element with the overcharge detection unit to fuse the fuse element of the SCP. Therefore, even when an abnormality occurs in the voltage detection circuit of the control circuit, etc., it has the feature of reliably prohibiting the charge and discharge of the battery unit and preventing overcharge.

[0021] A power supply including a battery unit according to another embodiment of the present invention has a detection unit that detects the temperature of the battery unit or battery cell, compares the detected temperature with a threshold value, and determines an abnormal state.

[0022] A power supply including a battery unit according to another embodiment of the present invention connects a diode in series with each switching element in the energization direction of the switching element.

[0023] The above battery has a feature that it can surely fuse the fuse element of SCP by controlling a plurality of switching elements to be in an on state together. This is because the switching elements that are switched to the on state simultaneously are supplied with voltage only from the switching element to which the maximum voltage is supplied. This power supply also realizes the feature that it can surely fuse the fuse element of SCP by setting a plurality of switching elements in an on state in the boundary region of the cell voltage that selects each switching element.

[0024] A power supply including a battery unit according to another embodiment of the present invention uses a FET as the switching element.

[0025] Hereinafter, the present invention will be described in detail with reference to the drawings. In the following description, terms indicating a specific direction or position (for example, "up", "down", and other terms including these terms) are used as necessary, but the use of these terms is for facilitating the understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms. Also, parts denoted by the same reference numerals in a plurality of drawings indicate the same or equivalent parts or members. Furthermore, the embodiments shown below are specific examples of the technical idea of the present invention and do not limit the present invention below. Also, the dimensions, materials, shapes, relative arrangements, etc. of the components described below are not intended to limit the scope of the present invention only to those, but are intended to be illustrative unless specifically described. Also, the content described in one embodiment or example is applicable to other embodiments or examples. Also, the sizes and positional relationships of the members shown in the drawings may be exaggerated for clarity of explanation.

[0026] (Embodiment 1) The power supply 100 in FIG. 1 includes a battery unit 1, an SCP3 (Self-Control Protector) that is connected in series to the output side of the battery unit 1 and cuts off the charge / discharge current in the abnormal state of the battery unit 1 or the load, a switch 6 that connects the SCP3 to the battery unit 1 and supplies power to the heater 5 of the SCP3 with the power of the battery unit 1 to melt the fuse element 4, and a control circuit 7 that controls the on / off of the switch 6 in the abnormal state.

[0027] (Battery Unit 1) The battery unit 1 includes a plurality of battery cells 2 connected in series with each other. The battery cell 2 is preferably a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery having a large charge / discharge capacity. However, the present invention does not specify the battery cell as a lithium ion secondary battery, and all secondary batteries currently used or to be developed for the battery cell, such as nickel metal hydride batteries and all-solid-state batteries, can also be used.

[0028] The battery unit 1 connects a plurality of battery cells 2 in series to increase the output voltage. In this battery unit 1, the voltage at the intermediate connection points where the plurality of battery cells 2 are connected in series gradually increases. For example, in the battery unit 1 that connects battery cells 2 composed of lithium-ion secondary batteries with a rated voltage of 3.7V in series, the voltage at the connection points of the battery cells 2 gradually increases as an integer multiple of the cell voltage from the negative side to the positive side. Therefore, the voltage at the intermediate connection points where the battery cells 2 are connected in series gradually increases. The battery unit 1 in FIG. 1 connects the heater 5 of the SCP3 via the switching element 10 using intermediate connection points with different voltages as different voltage terminals 11. The different voltage terminals 11 are provided to adjust the voltage supplied to the heater 5 of the SCP3. The voltage of the battery unit 1 changes from a fully charged state to a completely discharged state. For example, a lithium-ion secondary battery has a fully charged voltage of 4.2V and a completely discharged voltage of 2.8V. Therefore, for example, the total voltage of the battery unit 1 with 10 battery cells 2 connected in series changes from 28V to 42V, and the battery unit 1 with 14 battery cells 2 connected in series changes from 39.2V to 58.8V.

[0029] The battery unit 1 is provided with a plurality of different voltage terminals 11 with different numbers of battery cells 2 connected in series in order to supply a voltage within a set range to the heater 5 of the SCP3 from a plurality of battery cells 2 with a changing voltage via the switching element 10. When the voltage of the battery cell 2 decreases, the switching element 10 is connected to the different voltage terminal 11 that increases the number of battery cells 2 connected in series to supply power to the heater 5 of the SCP3. Conversely, when the voltage of the battery cell 2 increases, the switching element 10 is connected to the different voltage terminal 11 with a smaller number of battery cells 2 connected in series to adjust the supply voltage to the heater 5 of the SCP3 within the set range.

[0030] The battery unit 1 in Fig. 1 is provided with first to third different-voltage terminals 11a, 11b, and 11c. The battery unit 1 switches the different-voltage terminal 11 connected to the SCP3 in a state where the voltage of the battery cell 2 changes, and outputs a voltage within the set range to the SCP3. For example, the SCP3 of the surface-mounted fuse "SFK3045x" of Dexerials Corporation has a supply voltage range of 22.3 to 31.5V. This SCP3 is connected to the SCP3 via the switching element 10 from the following first to third different-voltage terminals 11a, 11b, and 11c, and can blow the fuse element 4. The first different-voltage terminal 11a is connected to the SCP3 in a state where the cell voltage changes from 3.2 to 4.35V, and the output voltage from the 7-series battery cells 2 is 22.4 to 30.45V. The second different-voltage terminal 11b is connected to the SCP3 in a state where the cell voltage changes from 2.5 to 3.5V, and the output voltage from the 9-series battery cells 2 is 22.5 to 31.5V. The third different-voltage terminal 11c is connected to the SCP3 in a state where the cell voltage changes from 1.9 to 2.6V, and the output voltage from the 12-series battery cells 2 is 22.8 to 31.2V.

[0031] (Switch 6) Switch 6 includes a plurality of switching elements 10 connected to a plurality of different-voltage terminals 11. The power supply 100 in Fig. 1 includes first to third switching elements 10a, 10b, and 10c connected to the first to third different-voltage terminals 11a, 11b, and 11c. Since Switch 6 connects each different-voltage terminal 11 to the SCP3, it consists of the same number of switching elements 10 as the different-voltage terminals 11. Since the power supply 100 in Fig. 1 is provided with three sets of different-voltage terminals 11 in the battery unit 1, three sets of switching elements 10 are used. However, for a power supply of a battery unit with two sets of different-voltage terminals, two sets of switching elements are used, and for a power supply with four or more sets of different-voltage terminals, each different-voltage terminal is connected to the SCP via four or more sets of switching elements.

[0032] The first to third switching elements 10a, 10b, and 10c preferably use FETs. The power supply 100 in FIG. 1 uses n-channel FETs for each switching element 10, connecting the drain to SCP3 via the diode 12, the source to the battery unit 1, and the gate to the control circuit 7. The above power supply 100 uses an n-channel FET as the switching element 10, but other semiconductor switching elements that can be switched on and off, such as p-channel FETs and bipolar transistors, can also be used as the switching element.

[0033] The switch 6 in FIG. 1 connects the diode 12 in series with the switching element 10. The diode 12 is connected in the energization direction of the on-state switching element 10. The diode 12 connected to the switching element 10 allows current to flow from the drain to the source in the energization direction of the switching element 10, which is an n-channel FET in FIG. 1, and blocks the current flowing in the opposite direction. Therefore, in a state where a plurality of FETs are switched to the on state, power is supplied by energizing only the FET connected to the different voltage terminal 11 of the maximum voltage to the heater 5 of SCP3.

[0034] The power supply 100 in Fig. 1 turns on the first switching element 10a when the cell voltage of the battery unit 1 is in the range of 3.2 to 4.35V, turns on the second switching element 10b when the cell voltage is in the range of 2.5 to 3.5V, and turns on the third switching element 10c when the cell voltage is in the range of 1.9 to 2.6V. When the cell voltage of the battery unit 1 is 3.3V, the first switching element 10a and the second switching element 10b are turned on. However, the current of the second switching element 10b passes through the diode 12, while the current of the first switching element 10a is blocked by the diode 12. When the cell voltage of the battery unit 1 is in the range of 2.5V, the second switching element 10b and the third switching element 10c are switched to the on state. Even in this state, the current flowing from the battery unit 1 to SCP3, the current of the third switching element 10c becomes the forward current of the diode 12, while the current of the second switching element 10b becomes the reverse current of the diode 12. Therefore, the third switching element 10c supplies current from the battery unit 1 to SCP3. As described above, the power supply 100 with the diode 12 connected in series to each switching element 10 can surely supply current from the battery unit 1 to SCP3 by switching a plurality of switching elements 10 to the on state at the boundary voltage where the cell voltage selects the switching element 10, and has the feature of being able to melt the fuse element 4 of SCP3. In particular, in all ranges of the fluctuating cell voltage, current can surely be supplied from the battery unit 1 to SCP3, and the fuse element 4 can be heated and melted by the heater 5.

[0035] (Control circuit 7) In an abnormal state, the control circuit 7 switches the switching element 10 from off to on, energizes the heater 5 of the SCP3 from the battery unit 1, and melts the fuse element 4. The control circuit 7 includes a voltage detection circuit 8 that detects the voltage of the battery unit 1 or the battery cell 2, and a selection circuit 9 that selects the switching element 10 to be switched to the on state based on the detected voltage of the voltage detection circuit 8. In an abnormal state, the selection circuit 9 selects the switching element 10 to be switched to the on state, connects the battery unit 1 to the heater 5 via the on-state switching element 10, and melts the fuse element 4. The control circuit 7 selects the switching element 10 based on the voltage of the battery cell 2 and supplies a voltage within a predetermined set range from the battery unit 1 to the SCP3.

[0036] The present invention does not identify an abnormal state. However, an abnormal state is, for example, a state in which the current of the battery unit 1 is cut off to achieve safety, or a state in which the battery unit 1 is protected. In this state, the fuse element 4 of the SCP3 connected to the output side of the battery unit 1 is melted to cut off the current. Specifically, the control circuit 7 determines an abnormal state when the total voltage of the battery unit 1 or the voltage of the battery cell 2 exceeds the maximum threshold voltage or is below the minimum threshold voltage, when the battery unit 1 or the battery cell 2 is overcharged or overdischarged, when the current of the battery unit 1 or the battery cell 2 exceeds the maximum threshold current, when the temperature of the battery unit 1 or the battery cell 2 exceeds the maximum threshold temperature or is below the minimum threshold temperature, and so on. However, since the present invention does not identify an abnormal state, for example, various other states that reduce the safety of the power supply can also be determined as abnormal states.

[0037] The control circuit 7 includes a detection unit 16 that detects an abnormal state. The detection unit 16 detects the abnormal state, switches the switching element 10 from off to on, and blows the fuse element 4 of the SCP3. The control circuit 7, in an abnormal state, detects the voltage of the battery cell 2 with the voltage detection circuit 8, and selects the switching element 10 that the selection circuit 9 switches from off to on. The control circuit 7 in FIG. 1 includes, as the detection unit 16, an AFE (analog front end) 13 that detects the voltage, current, temperature, etc. of the battery unit 1 and each battery cell 2, converts them into digital signals, and outputs them, an MPU (microprocessor unit) 14 that calculates the digital signals output from the AFE 13, and an overcharge detection unit 15 that detects overcharge by detecting the voltage of the battery unit 1.

[0038] The AFE (analog front end) 13 includes a voltage detection circuit 8 that detects the voltage of each battery cell 2, and the MPU (microprocessor unit) 14 includes a voltage detection circuit 8 that detects the total voltage of the battery unit 1. This detection unit 16 can compare the cell voltage of the battery cell 2 detected by the AFE 13 and the total voltage of the battery unit 1 detected by the MPU 14 with a threshold value to make an abnormality determination. Furthermore, the detection unit 16 can also detect the temperature of the battery unit 1 or the battery cell 2, and compare the detected temperature with a threshold value to determine an abnormal state. The detection unit 16 shown in FIG. 1 includes a temperature sensor 17, and through this temperature sensor 17, it detects the temperature of the battery unit 1 or the battery cell 2.

[0039] The MPU 14 calculates the remaining capacity of the battery unit 1 and the battery cell 2 by calculating the digital signals input from the AFE 13, compares the remaining capacity and the detected voltage with a threshold value to determine an abnormal state, and in a state determined to be an abnormal state, outputs an on voltage to the gate of the switching element 10. In the power supply 100 of FIG. 1, an n-channel FET is used for the switching element 10, the drain is connected to the heater 5 of the SCP3 via the diode 12, the source is connected to the battery unit 1, and the gate is connected to the MPU 14. Therefore, the MPU 14 inputs a voltage to the gate such that the gate voltage with respect to the source becomes an on voltage to switch the switching element 10 from off to on.

[0040] The MPU 14 is provided with a selection circuit 9 that selects the first, second, and third switching elements 10a, 10b, and 10c based on the cell voltage of the battery unit 1 and switches them from off to on. For example, when the cell voltage is in the range of 3.2 to 4.35V, the selection circuit 9 switches the first switching element 10a from off to on; when the cell voltage is in the range of 2.5 to 3.5V, it switches the second switching element 10b from off to on; and when the cell voltage is in the range of 1.9 to 2.6V, it switches the third switching element 10c from off to on. In an abnormal state, as the cell voltage gradually decreases, the selection circuit 9 can switch at least one of the switching elements 10 from off to on. When switching from the first switching element 10a to the second switching element 10b at the timing of switching the switching element 10 that turns on, both the first switching element 10a and the second switching element 10b are in the on state, and in an abnormal state, surely one of the switching elements 10 is in the on state. The above power supply 100 has the feature that in an abnormal state, surely one of the switching elements 10 is in the on state and the current can be cut off by the SCP 3. Since each switching element 10 has a diode 12 connected in series, when a plurality of switching elements 10 are in the on state, a plurality of different voltage terminals 11 are connected to the heater 5 of the SCP 3 through the plurality of switching elements 10 that have been switched to the on state. In this state, only one different voltage terminal 11 supplies power to the SCP 3. When a plurality of switching elements 10 are in the on state, the plurality of switching elements 10 connect the positive side and the negative side of the battery cell 2, but the diode 12 blocks the discharge current of the battery cell 2 and prevents a short-circuit current from flowing.

[0041] In addition to the MPU 14, the power supply 100 in FIG. 1 also has an overcharge detection unit 15 that detects overcharging of the battery unit 1 and cuts off the current with the SCP 3. The overcharge detection unit 15 detects the total voltage of the battery unit 1 and switches the first switching element 10a from off to on. Since the overcharge detection unit 15 detects overcharging of the battery unit 1, the cell voltage is high in this state, and the overcharge detection unit 15 switches the first switching element 10a from off to on. Therefore, the first switching element 10a has an on voltage input to its gate from both the MPU 14 and the overcharge detection unit 15 and is switched from off to on. The above power supply 100 switches the first switching element 10a from off to on with both the MPU 14 and the overcharge detection unit 15. Therefore, even if the AFE 13 or the MPU 14 does not operate normally, the overcharge detection unit 15 can switch the first switching element 10a from off to on and cut off the charging current with the SCP 3.

[0042] Furthermore, the power supply 100 in FIG. 1 connects a discharge switching element 19 that cuts off the discharge current and a charge switching element 18 that cuts off the charging current in series with the output side of the battery unit 1, and controls the on / off states of the discharge switching element 19 and the charge switching element 18 with the AFE 13. When the detected voltage of the battery unit 1 or the battery cell 2 becomes lower than the minimum voltage, the AFE 13 switches the discharge switching element 19 from on to off to cut off the discharge current, and when it becomes higher than the maximum voltage, the AFE 13 switches the charge switching element 18 from on to off to cut off the charging current.

Industrial Applicability

[0043] The present invention is a power supply including a battery unit, and in particular, it is preferably used for a power supply that includes an SCP (Self-Control Protector) on the output side of the battery unit and cuts off the current with the SCP in case of an abnormality.

Explanation of Reference Numerals

[0044] 100... Power supply 1... Battery unit 2... Battery cell 3... SCP 4…Fuse element 5…Heater 6…Switch 7…Control circuit 8…Voltage detection circuit 9…Selection circuit 10…Switching element 10a…First switching element 10b…Second switching element 10c…Third switching element 11…Different voltage terminal 11a…First different voltage terminal 11b…Second different voltage terminal 11c…Third different voltage terminal 12…Diode 13…AFE 14…MPU 15…Overcharge detection unit 16…Detection unit 17…Temperature sensor 18…Charge switching element 19…Discharge switching element

Claims

1. A battery unit, an SCP (Self-Control Protector) connected in series with the battery unit to cut off the charge and discharge current in an abnormal state, a switch formed by connecting the SCP to the battery unit, A power supply comprising a control circuit for turning the switch on and off, The battery unit includes a plurality of battery cells connected in series with each other, The SCP, a fuse element connected in series on the output side of the battery unit, a heater connected to the battery unit and generating heat by Joule heat to melt the fuse element, The switch, connects one terminal to the heater, and includes a plurality of switching elements formed by connecting the other terminal to a plurality of different voltage terminals having different voltages of the battery unit, The control circuit, a voltage detection circuit for detecting the voltage of the battery unit or the battery cell, a selection circuit for selecting the switching element to be switched to the on state based on the detected voltage of the voltage detection circuit, In an abnormal state, the selection circuit, selects the switching element to be switched to the on state, A power supply comprising a battery unit, characterized in that the switching element in the on state connects the battery unit to the heater to melt the fuse element.

2. A power supply comprising the battery unit according to claim 1, The control circuit includes a detection unit for detecting an abnormal state, and in a state where the detection unit detects an abnormal state, the switching element is turned on to melt the fuse element. A power supply comprising a battery unit.

3. A power supply comprising the battery unit according to claim 2, The detection unit, an AFE (Analog Front End) for detecting the voltage of each battery cell, an MPU (Microprocessor Unit) for detecting the total voltage of the battery unit, A power supply comprising a battery unit, which compares the cell voltage of the battery cell detected by the AFE and the total voltage of the battery unit detected by the MPU with a threshold value to determine an abnormality.

4. A power supply comprising the battery unit according to claim 2 or 3, The detection unit has an overcharge detection unit for detecting overcharge of the battery unit, A power supply comprising a battery unit, wherein the overcharge detection unit detects overcharge of the battery unit and melts the fuse element of the SCP.

5. A power supply comprising the battery unit according to any one of claims 2 to 4, A power supply comprising a battery unit in which a detection unit detects the temperature of the battery unit or the battery cell, compares the detected temperature with a threshold value, and determines an abnormal state.

6. A power supply comprising the battery unit according to any one of Claims 1 to 5, A power supply comprising a battery unit in which a diode is connected in series with each of the switching elements in the energization direction of the switching element.

7. A power supply comprising the battery unit according to any one of Claims 1 to 6, A power supply comprising a battery unit in which the switching element is an FET.

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