Backup circuit and charging system for use in shopping cart

Abstract

To provide a backup circuit and a charging system which can stably supply power to an electronic apparatus with which a battery is connected.SOLUTION: According to an embodiment, a backup circuit comprises a super capacitor, a PTC thermistor, and a diode. The super capacitor is provided between output of a battery and an electronic apparatus via the PTC thermistor. The diode is provided in parallel with the PTC thermistor.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] An embodiment of the present invention comprises: Used in shopping carts This invention relates to a backup circuit and a charging system. [Background technology]

[0002] In recent years, some shopping carts have been equipped with electronic devices, such as tablet computers with built-in batteries. These shopping carts are equipped with an external battery that supplies power to the attached electronic devices to enable long-term continuous operation of the electronic devices. The electronic devices installed in the shopping cart operate by charging their built-in internal batteries with power supplied from the external battery.

[0003] Some batteries used as external batteries support pass-through charging, which allows them to output power even while charging. However, even if the external battery supports pass-through charging, there may be a momentary interruption in the output when charging begins or ends. A momentary interruption in the output from the external battery can cause the operation of electronic devices such as tablet devices to become unstable. For example, a momentary interruption in the output from the external battery can cause tablet devices to detect an abnormality, such as an unconnected external battery, or cause operational problems. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-151219 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide a battery that can stably supply power to an electronic device connected to the battery. Used in shopping carts To provide a backup circuit and a charging system. [Means for solving the problem]

[0006] According to an embodiment, Used in shopping carts The backup circuit is This is a backup circuit used in shopping carts equipped with electronic devices connected to batteries that support pass-through charging. Supercapacitor, PTC thermistor, and diode A first connector and a second connector The supercapacitor comprises: The aforementioned Battery output and The aforementioned A PTC thermistor is placed between the device and the PTC thermistor. The diode is connected in parallel to the PTC thermistor. The first connector is a connector for connecting to the interface of the battery, and the second connector is a connector provided downstream of the PTC thermistor and the diode and for connecting to the electronic device. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a shopping cart equipped with a charging system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing a first configuration example of a backup circuit in a charging system according to an embodiment. [Figure 3] FIG. 3 is a diagram showing an example of voltage waveforms at various parts when a momentary interruption of the battery occurs in the charging system according to the embodiment. [Figure 4] FIG. 4 is a diagram showing a second configuration example of the backup circuit in the charging system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, a charging device and a charging system according to an embodiment will be described with reference to the drawings. FIG. 1 is a perspective view showing a shopping cart 1 equipped with a charging system 2 according to an embodiment. A shopping cart (hereinafter also simply referred to as a cart) 1 is an example of a mobile object equipped with a charging system 2. The shopping cart 1 is used, for example, for shopping in a store or the like.

[0009] The charging system 2 is connected to the electronic device 3 mounted on the cart 1. The charging system 2 has a backup circuit 21, a battery 22, and a power receiver 23. The backup circuit 21 is provided between the electronic device 3 and the battery 22. The electronic device 3 acquires the power output by the battery 22 through the backup circuit 21. The battery 22 outputs the stored power at a predetermined power value. The output side of the battery 22 is connected to the electronic device 3 via the backup circuit 21. The input side of the battery 22 is connected to the power receiver 23. The power receiver 23 receives power transmitted from an external power transmitter 50. The power receiver 23 supplies the received power to the battery 22 as power for charging.

[0010] The electronic device 3 mounted on the cart 1 receives power output from a battery 22 via a backup circuit 21. The electronic device 3 mounted on the cart 1 includes a computer such as a tablet terminal 31. For example, a computer such as the tablet terminal 31 includes an internal battery and uses the input power to perform operations such as charging the internal battery. If the input power is interrupted momentarily, the computer such as the tablet terminal 31 may determine that the battery 22 is not connected and may issue a warning message or detect an abnormality in the battery 22. The backup circuit 21 outputs stable power even if the output of the battery 22 is interrupted momentarily, so that the operation of the computer such as the tablet terminal 31 does not become unstable.

[0011] 1, the cart 1 has a movable cart body 11 that can store products therein. The cart body 11 is configured to store products therein and move by operation of the user. The cart body 11 has a storage basket 12 for storing products. The storage basket 12 is supported by a frame 14 having four casters 15 (1511, 1512, 1521, 1522). The four casters 15 are provided at the four corners of the lower part of the frame 14. Each caster 15 (1511, 1512, 1521, 1522) has front wheels 1311 and 1312 and rear wheels 1321 and 1322 that rotate in the direction of movement. The cart body 11 moves when the wheels 13 of each caster 15 rotate on the floor surface. Furthermore, each caster 15 is configured so that the rotation direction of the wheels 13 can be freely rotated. This allows the cart body 11 to freely change its direction of movement.

[0012] A handle 16 is provided on the frame 14 on the front side of the storage basket 12. The handle 16 is held by a user. For example, the user holds the handle 16 to move the cart body 11. In this embodiment, the direction in which the user pushes the storage basket 12 from the handle 16 held by the user is defined as the forward direction.

[0013] Furthermore, the lower part of frame 14, on which four casters 15 are provided at the four corners, is narrower at the front and wider at the rear in the forward direction. Therefore, casters 1511 and 1512 supporting the front wheels are narrower in width from side to side than casters 1521 and 1522 supporting the rear wheels. As a result, when multiple carts are stored lined up one behind the other, the frames of the rear carts are stored so that they overlap along the frame of the front cart.

[0014] In addition, in the embodiment, the handle 16 side of the storage basket 12 is referred to as the front side, and the opposite side, that is, the front of the cart, is referred to as the tip side. The storage basket 12 has an opening / closing surface 121 on the front side that can be opened and closed with the lower end as the free end. The storage basket 12 is also formed so that the surface on the tip side is smaller than the front side that serves as the opening / closing surface 121. As a result, when multiple carts are stored lined up in front of each other, the rear cart pushes up the opening / closing surface 121 of the front cart, so that the storage baskets 12 of the front and rear carts are stored so that they overlap.

[0015] Electronic devices 3, including tablet terminals 31 serving as computers with internal batteries, are attached to the cart body 11. The electronic devices 3 are devices for providing information and services to users. In the configuration example shown in FIG. 1, each electronic device 3 is attached to a handle 16 of a storage basket 12.

[0016] FIG. 1 illustrates a tablet terminal 31, a product reader 32, and a card reader 33 as examples of the electronic device 3. The tablet terminal 31 has an exterior with a display unit equipped with a touch panel. The tablet terminal 31 is installed with the display unit facing the user positioned on the handle 16 side. For example, the tablet terminal 31 displays information about products read by the product reader 32. The tablet terminal 31 may also have a function for processing the payment for the products read by the product reader 32.

[0017] The product reader 32 as the electronic device 3 is a device that reads product information. The product reader 32 may have a display unit that displays the read product information. For example, the product reader 32 is a scanner that reads product identification information such as a barcode attached to a product being put into or taken out of the storage basket 12. The product reader 32 may also be an RFID tag reader that reads an RFID tag or the like attached to a product. The card reader 33 as the electronic device 3 is a card reader that reads a credit card, membership card, or the like owned by a user.

[0018] The tablet terminal 31 is an example of a computer equipped with a processor, memory, various interfaces, an internal battery, etc. The tablet terminal 31 receives power output from the battery 22 via the backup circuit 21. The tablet terminal 31 performs operations including charging the internal battery using the power received via the backup circuit 21.

[0019] The cart body 11 is equipped with a backup circuit 21, a battery 22, and a power receiver 23, which constitute the charging system 2. The power receiver 23 includes a power receiving coil and a power receiving circuit. The power receiver 23 receives power transmitted from the power transmitting coil of the power transmitter 50. The power receiver 23 supplies the power received from the power transmitter 50 to the battery 22 as power for charging.

[0020] The power receiver 23 is attached to the cart body 11 so that the power receiving coil faces the power transmitting coil of the power transmitter 50. In the configuration example shown in Fig. 1, the power receiver 23 is installed on the side of the cart body 1 so that the power receiving coil is approximately perpendicular to the floor surface. Furthermore, when the power transmitting coil of the power transmitter 50 is installed on the floor surface, the power receiver 23 may be installed on the bottom of the cart body 1 so that the power receiving coil faces the floor surface.

[0021] For example, the power transmitter 50 is installed in a cart parking area where the cart 1 is stored. The power receiver 23 mounted on the cart body 11 receives power contactlessly from the power transmitter 50 installed in the cart parking area when the cart 1 is stored in the cart parking area. As a result, when the cart 1 is stored in the cart parking area, the battery 22 mounted on the cart body 11 is charged by the power that the power receiver 23 receives contactlessly from the power transmitter 50.

[0022] The battery 22 and the backup circuit 21 are stored in a box. The box storing the battery 22 and the backup circuit 21 is attached to the cart body 11. The battery 22 is connected to the power receiver 23 while stored in the box attached to the cart body 11. As a result, the battery 22 obtains the power received by the power receiver 23 from the power transmitter 50 as charging power. In other words, the battery 22 is charged contactlessly and serves as a power source device for operating each electronic device 3 including the tablet terminal 31.

[0023] The backup circuit 21 is provided between the battery 22 and the electronic device 3 including the tablet terminal 31. The backup circuit 21 is stored in a box while connected to the battery 22 and the electronic device 3 including the tablet terminal 31. The backup circuit 21 is a circuit for stably supplying the power output by the battery 22 to the electronic device 3 including the tablet terminal 31.

[0024] Next, the configuration of the backup circuit 21 in the charging system 2 according to the embodiment will be described. FIG. 2 is a diagram showing a backup circuit 211 of a first configuration example in the charging system 2 according to the embodiment. In the configuration example shown in FIG. 2, the charging system 2 includes a backup circuit 211, a battery 22, and a power receiver . The power receiver 23 receives the power transmitted from the power transmission coil of the power transmitter 50. The power receiver 23 receives the power transmitted by the power transmitter 50, for example, in a contactless manner. The power receiver 23 supplies the power received from the power transmitter 50 to the battery 22. Note that the power receiver 23 may be in physical contact with the power transmitter 50 to receive the power from the power transmitter 50.

[0025] The battery 22 has a battery cell that stores power. The battery 22 includes an input interface 221 and an output interface 222. The input interface 221 of the battery 22 is connected to the power receiver 23 that receives power from the power transmitter 50. The battery 22 stores the power received by the power receiver 23 and input to the input interface 221 in the battery cell. The output interface 222 of the battery 22 is connected to the backup circuit 211. The battery 22 outputs the power stored in the battery cell from the output interface 222.

[0026] The backup circuit 211 is provided between the battery 22 and the electronic device 3 including the tablet terminal 31. The backup circuit 211 of the first configuration example shown in FIG. 1 includes a first connector 41, a second connector 42, a supercapacitor 43, a diode 44, a resistor 45, and a boost circuit 46.

[0027] The first connector 41 is an input section of the backup circuit 211, and the second connector 42 is an output section of the backup circuit 211. The first connector 41 is connected to the output interface 222 of the battery 22. Within the backup circuit 211, the first connector 41 is connected to the second connector 42 via a boost circuit 46.

[0028] A supercapacitor 43, a diode 44, and a resistor 45 are provided between the first connector 41 and the boost circuit 46. The supercapacitor 43 is connected to the first connector 41 and the boost circuit 46 via the diode 44. The supercapacitor 43 is also connected to the first connector 41 and the boost circuit 46 via the resistor 45.

[0029] The supercapacitor 43 is an electric double layer capacitor (EDLC) or the like. The supercapacitor 43 can store a large amount of electrical energy and can be charged and discharged at high speed. In the backup circuit 211 shown in FIG. 2, the supercapacitor 43 is charged when power is being supplied from the battery 22 to the first connector 41. When the power supply from the battery 22 is stopped, the supercapacitor 43 discharges the stored power.

[0030] Resistor 45 limits the value of the current for charging supercapacitor 43. The resistance value of resistor 45 is set according to the load current (maximum current consumption of the tablet terminal) and the maximum output value of battery 22. The diode 44 is provided in parallel with the resistor 45 to ensure a sufficient amount of discharge from the supercapacitor 43. The diode 44 is, for example, a Schottky barrier diode (SBD).

[0031] The boost circuit 46 is a circuit for maintaining an appropriate voltage value to be supplied to the electronic device 3, such as the tablet terminal 31. When the output from the battery 22 is stopped, the boost circuit 46 boosts the voltage discharged from the supercapacitor 43 to an appropriate voltage value and supplies it to the tablet terminal 31. For example, the boost circuit 46 maintains the voltage discharged from the supercapacitor 43 at an appropriate voltage value during the period when the output from the battery 22 is stopped due to a momentary interruption.

[0032] The backup circuit 211 of the first configuration example charges the supercapacitor 43 with a charging current limited by the resistor 45 during the period when power is supplied from the battery 22. During the period when the power supply from the battery 22 is stopped due to a momentary interruption, the backup circuit 211 adjusts the voltage discharged from the supercapacitor 43 to an appropriate value using the boost circuit 46 and outputs the voltage to the electronic device 3. In other words, the backup circuit 211 can continue to supply stable power to the electronic device (load) 3 even if a momentary interruption occurs in the output of the battery 22 due to the charging operation of the battery 22, etc.

[0033] FIG. 3 is a diagram showing an example of measuring the voltages at various points in the backup circuit 21. FIG. 3 shows the measurement results of the output voltage Vb of the battery 22, the output voltage Vo of the boost circuit 46, and the discharge voltage Vc of the supercapacitor 43. In FIG. 3, the horizontal axis represents time, and one division on the horizontal axis represents 5 seconds. In the example shown in FIG. 3, the current consumption of the tablet terminal 31 serving as the electronic device 3, which serves as the load, is 1.5 A. The period during which the output of the battery 22 is stopped (the period of momentary blackout) is assumed to be approximately 300 ms.

[0034] As shown in Figure 3, when the output of battery 22 is stopped, supercapacitor 43 discharges. If the period during which the output of battery 22 is stopped (period of momentary blackout) is about 300 ms, output voltage Vo is maintained at 5.2 V due to discharge from supercapacitor 43. In the example shown in Figure 3, there is also a period during which the momentary blackout of about 300 ms causes the battery output to be repeatedly turned on and off approximately every two seconds. Even during this period, the discharge voltage of supercapacitor 43 gradually decreases, but the output voltage Vo of backup circuit 21 can be maintained at a predetermined value (5.2 V).

[0035] The battery 22 may experience a momentary interruption in output when the electrical connection between the power receiver 23 and the power transmitter 50 is switched. For example, in a system in which the power receiver 23 mounted on the cart 1 receives power from the power transmitter 50 in a contactless manner, the power receiving state is turned on and off depending on the change in the positional relationship between the power receiver 23 and the power transmitter 50. Power is supplied from such a power receiver 23 to the battery 22. For this reason, the battery 22 is prone to a momentary interruption in output due to the power receiver 23 turning on and off the power receiving state.

[0036] Even if the output of the battery 22 is momentarily interrupted, the backup circuit 211 continues to supply power to the electronic device 3 using the power discharged from the supercapacitor. As a result, the cart 1 equipped with the charging system 2 having the backup circuit 211 can stably supply power to electronic devices such as tablet terminals.

[0037] Next, another configuration of the backup circuit 21 in the charging system 2 according to the embodiment will be described. FIG. 4 is a diagram showing a backup circuit 212 of a second configuration example in the charging system 2 according to the embodiment. In the configuration example shown in FIG. 4, the charging system 2 includes a backup circuit 212, a battery 22, and a power receiver . The power receiver 23 and the battery 22 can be realized with the same configuration as that shown in Fig. 2 above. That is, the power receiver 23 receives power transmitted by the power transmitter 50 in a wireless manner and supplies the power received from the power transmitter 50 to the battery 22. The input interface 221 of the battery 22 is connected to the power receiver 23, and the output interface 222 is connected to the backup circuit 212.

[0038] The backup circuit 212 is provided between the battery 22 and the electronic device 3 including the tablet terminal 31. The backup circuit 212 of the second configuration example shown in FIG. 4 includes a first connector 41, a second connector 42, a supercapacitor 43, a diode 44, a resistor 45, a boost circuit 46, and a PTC thermistor 47.

[0039] The first connector 41 is an input section of the backup circuit 212. The second connector 42 is an output section of the backup circuit 212. The first connector 41 is connected to the output interface 222 of the battery 22. Within the backup circuit 212, the first connector 41 is connected to the second connector 42 via a boost circuit 46.

[0040] 4, a supercapacitor 43, a diode 44, a resistor 45, and a PTC thermistor 47 are provided between the first connector 41 and the boost circuit 46. The supercapacitor 43 is connected to the first connector 41 and the boost circuit 46 via the diode 44. The supercapacitor 43 is also connected to the first connector 41 and the boost circuit 46 via the resistor 45 and the PTC thermistor 47 connected in series.

[0041] The supercapacitor 43 is an electric double layer capacitor (EDLC) or the like. The supercapacitor 43 can store a large amount of electrical energy and can be charged and discharged at high speed. In the backup circuit 212 shown in FIG. 2, the supercapacitor 43 is charged when power is being supplied from the battery 22 to the first connector 41. When the power supply from the battery 22 is stopped, the supercapacitor 43 discharges the stored power.

[0042] Resistor 45 and PTC thermistor 47 limit the value of the current for charging supercapacitor 43. The resistance value of resistor 45 is set according to the characteristics of PTC thermistor 47, the load current (maximum current consumption of the tablet terminal), and the maximum output value of battery 22. The diode 44 is provided in parallel with the resistor 45 and the PTC thermistor 47 to ensure a sufficient amount of discharge from the supercapacitor 43. The diode 44 is, for example, a Schottky barrier diode (SBD).

[0043] The boost circuit 46 is a circuit for maintaining an appropriate voltage value to be supplied to the electronic device 3, such as the tablet terminal 31. When the output from the battery 22 is stopped, the boost circuit 46 boosts the voltage discharged from the supercapacitor 43 to an appropriate voltage value and supplies it to the tablet terminal 31. For example, the boost circuit 46 maintains the voltage discharged from the supercapacitor 43 at an appropriate voltage value during the period when the output of the battery 22 is stopped due to a momentary interruption.

[0044] The PTC thermistor 47 is an example of a resistor and an overcurrent protection element. The PTC thermistor 47 is a temperature-dependent resistive element whose resistance value increases as the temperature increases. For example, the PTC thermistor 47 operates as a resistor with a predetermined resistance value at room temperature. The resistance value of the PTC thermistor 47 increases rapidly when the temperature exceeds a predetermined temperature (Curie temperature). When the temperature exceeds the Curie temperature due to heat generated by an overcurrent, the PTC thermistor 47 increases its resistance value, thereby limiting the overcurrent. In other words, the PTC thermistor 47 functions as a resistor with a predetermined resistance value when the temperature is below the Curie temperature, and functions as an overcurrent protection element when the temperature rises due to an overcurrent.

[0045] Like the backup circuit 211 of the first configuration example, the backup circuit 212 of the second configuration example can continue to supply power to the electronic device (load) 3 even if an instantaneous interruption occurs in the output of the battery 22. That is, while the battery 22 is supplying power, the backup circuit 212 charges the supercapacitor 43 with a charging current limited by the resistor 45. While the power supply from the battery 22 is stopped due to an instantaneous interruption, the backup circuit 211 maintains the voltage discharged by the supercapacitor 43 at an appropriate voltage value using the boost circuit 46 and outputs it to the electronic device 3.

[0046] Furthermore, if the supercapacitor 43 fails in short mode, a large current (overcurrent) flows through the resistor 45 in the backup circuit 211 of the first configuration example. In this case, unless the battery 22 stops output using its protection function, the large current continues to flow through the circuit. If the large current continues to flow, temperature rises cannot be suppressed, and there is a possibility that an abnormally high temperature may occur, or a failure may occur due to the abnormally high temperature.

[0047] To avoid such a situation, the backup circuit 212 of the second configuration example is provided with a PTC thermistor that functions as an overcurrent protection element when the temperature rises due to an overcurrent. The resistance value of the PTC thermistor increases rapidly when the temperature rises due to an overcurrent. If an overcurrent occurs due to a failure of the supercapacitor 43, the PTC thermistor 47 of the backup circuit 212 becomes highly resistant, thereby suppressing the overcurrent. As a result, the backup circuit of the second configuration example can maintain power supply to electronic devices and ensure safety even if a momentary interruption in battery output occurs.

[0048] 4, backup circuit 212 has resistor 45 connected in series with PTC thermistor 47. By connecting resistor 45 in series with PTC thermistor 47, backup circuit 212 can be designed by combining the characteristics of PTC thermistor 47 with the resistance value of resistor 45. This makes it easier to select a PTC thermistor for backup circuit 212, and increases the degree of freedom in circuit design.

[0049] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. The following additionally describes the contents of the claims as originally filed in this application. [1] A supercapacitor is provided between the battery output and the electronic device via a PTC thermistor; a diode connected in parallel to the PTC thermistor; A backup circuit comprising: [2] Further, a boost circuit for boosting an output is provided between the electronic device and the diode. [1] The backup circuit described in [1]. [3] Further, a resistor is provided in series with the PTC thermistor. [1] The backup circuit according to any one of [1] and [2]. [4] a power receiver that receives the power transmitted by the power transmitter; a battery having an input interface for inputting the power received by the power receiver and an output interface for outputting the stored power; a backup circuit including a supercapacitor connected between the output interface of the battery and an electronic device via a PTC thermistor, and a diode connected in parallel with the PTC thermistor; A charging system having: [5] The power receiver is installed in a mobile object and receives the power transmitted by the power transmitter in a non-contact manner. [4] A charging system according to the present invention. [Explanation of symbols]

[0050] 1...Shopping cart (mobile object), 2...Charging system, 21 (211, 212)...Backup circuit, 22...Battery, 23...Receiver, 31...Electronic device (tablet terminal), 41...First connector, 42...Second connector (connector), 43...Supercapacitor, 44...Diode, 45...Resistor, 46...Boost circuit, 47...PTC thermistor.

Claims

1. A backup circuit used in a shopping cart equipped with an electronic device connected to a battery that supports pass-through charging, comprising: a supercapacitor provided between the output of the battery and the electronic device via a PTC thermistor; a diode connected in parallel to the PTC thermistor; a first connector for connecting to an interface of the battery; a second connector provided downstream of the PTC thermistor and the diode for connection to the electronic device; A backup circuit for use in a shopping cart comprising:

2. Further, a boost circuit for boosting an output is provided between the electronic device and the diode. The backup circuit of claim 1 .

3. Further, a resistor is provided in series with the PTC thermistor.

3. The backup circuit according to claim 1 or 2.

4. A charging system mounted on a shopping cart, a power receiver that receives the power transmitted by the power transmitter; a pass-through charging compatible battery having an input interface for inputting the power received by the power receiver and an output interface for outputting the stored power; a backup circuit including: a supercapacitor provided between an output interface of the battery and an electronic device via a PTC thermistor; a diode provided in parallel with the PTC thermistor; a first connector for connecting to the interface of the battery; and a second connector provided downstream of the PTC thermistor and the diode for connecting to the electronic device; A charging system having:

5. The power receiver receives the power transmitted by the power transmitter in a non-contact manner. The charging system according to claim 4 .

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