vacuum cleaner

Abstract

To improve operability of a vacuum cleaner by grasping an operation mode and an operation executable time according to the deterioration of a secondary battery.SOLUTION: A vacuum cleaner 1 includes an electric blower 14 for generating suction force, a secondary battery 160 for supplying power to the electric blower 14, and a control device 100 for controlling the electric blower 14 and the secondary battery 160. The control device 100 can set a standard operation mode and a strong operation mode in which the rotation speed of the electric blower 14 is higher than that of the standard operation mode. When the strong operation mode is set, a time when a battery voltage of the secondary battery 160 reaches a lower limit set voltage or a time when a battery temperature of the secondary battery 160 reaches an upper limit set temperature, whichever is shorter, is made to be an operation executable time of the electric blower 14, and the operation executable time is displayed in a display unit 18.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention relates to an electric vacuum cleaner. [Background technology]

[0002] In rechargeable vacuum cleaners that use secondary batteries as a power source, operation may stop if the voltage of the secondary battery drops rapidly.

[0003] One technology that can solve this problem is the one described in Patent Document 1. In Patent Document 1, when determining the remaining charge of the secondary battery, different judgment voltages and different judgment times are set according to the operating state of the electric blower, and the operation control of the electric blower and notification of the remaining charge of the secondary battery are performed. Furthermore, Patent Document 1 has multiple criteria for determining the battery voltage, and the judgment time is also changed for each operating state of the electric blower and judgment criterion, thereby preventing the vacuum cleaner from suddenly stopping during cleaning while suppressing deterioration of accuracy, and ensuring that the limited battery capacity is used efficiently until the very end. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-600 [Overview of the project] [Problems that the invention aims to solve]

[0005] In electric vacuum cleaners, there is a high-power mode that rotates the electric blower more powerfully. In high-power mode, a large current is discharged from the secondary battery compared to the standard mode, which tends to raise the battery temperature. An upper temperature limit is set for the battery from the perspective of the lifespan and safety of the secondary battery. For example, the battery temperature tends to rise more easily when the ambient temperature is high or when the internal resistance increases due to the deterioration of the secondary battery. As a result, even if there is still battery charge remaining, the battery protection temperature threshold may be reached, and the operation of the electric blower may stop. In the technology described in Patent Document 1, it was not possible to know the operating time according to the operating mode and the deterioration of the secondary battery, resulting in poor operability.

[0006] The objective of the present invention is to solve the above problems and provide an electric vacuum cleaner that can determine the operating time according to the operating mode and the degradation of the secondary battery, thereby improving operability. [Means for solving the problem]

[0007] To achieve the above objective, the present invention provides an electric vacuum cleaner comprising an electric blower that generates suction force, a secondary battery that supplies power to the electric blower, and a control device that controls the electric blower and the secondary battery, wherein the control device can set a standard operating mode and a high-speed operating mode that increases the rotation speed of the electric blower compared to the standard operating mode, and when the high-speed operating mode is set, the operating time of the electric blower is set to the shorter of the time it takes for the battery voltage of the secondary battery to reach the lower limit set voltage or the time it takes for the battery temperature of the secondary battery to reach the upper limit set temperature, and the operating time is displayed on the display unit. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an electric vacuum cleaner that can understand the operating time according to the operating mode and the degradation of the secondary battery, thereby improving operability. [Brief explanation of the drawing]

[0009] [Figure 1]It is an external perspective view of the vacuum cleaner in a state housed in the stand according to an embodiment of the present invention. [Figure 2] It is an external perspective view of the vacuum cleaner in a state used as a stick type according to an embodiment of the present invention. [Figure 3] It is a control block diagram of the vacuum cleaner according to an embodiment of the present invention. [Figure 4] It is a diagram showing the configuration of the battery model 131 in the determination unit 140 according to an embodiment of the present invention. [Figure 5] It is a flowchart showing the processing content of the determination unit 140 according to an embodiment of the present invention. [Figure 6] It is a diagram showing the relationship among the operation time, the upper limit set temperature, and the lower limit set voltage when the capacity retention rate SOHQ is 100%. [Figure 7] It is a diagram showing the relationship among the operation time, the upper limit set temperature, and the lower limit set voltage when the capacity retention rate SOHQ is 90%. [Figure 8] It is a diagram showing the result of comparing the present example and a comparative example. Description of Embodiments

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In principle, the same reference numerals are assigned to the same elements in all drawings. Descriptions of portions having the same functions will be omitted. The configuration described below is merely an embodiment, and it is not intended that the embodiments of the present invention are limited to the following specific embodiments.

[0011] FIG. 1 is an external perspective view of the vacuum cleaner in a state housed in the stand according to an embodiment of the present invention. FIG. 2 is an external perspective view of the vacuum cleaner in a state used as a stick type according to an embodiment of the present invention.

[0012] In the present embodiment 1, as indicated by arrows, front-rear, left-right, and up-down directions are defined from the perspective of a user who performs cleaning.

[0013] As shown in FIG. 1 and FIG. 2, the electric vacuum cleaner 1 includes a vacuum cleaner main body 10 constituting an outer casing, an extension pipe 20 having one end connected to the vacuum cleaner main body 10, and a suction nozzle body 30 connected to the other end of the extension pipe 20. Further, in the electric vacuum cleaner 1 of the present embodiment, a brush portion 40 is provided at a tip end of the vacuum cleaner main body 10, and when the extension pipe 20 is removed from the vacuum cleaner main body 10, the electric vacuum cleaner 1 can be used as a handheld electric vacuum cleaner.

[0014] A dust collection chamber 12 covered with an openable / closable dust collection cover 11 is provided in a front portion of the vacuum cleaner main body 10. An electric blower 14 that generates suction force is provided behind the dust collection chamber 12, and a battery pack 16 having a plurality of secondary batteries 160 is provided behind the electric blower 14. The secondary batteries 160 supply electric power to the electric blower 14.

[0015] A handle portion 13 that is gripped by a user when performing cleaning is provided at an upper rear portion of the vacuum cleaner main body 10. An operation switch 17 for turning on / off the operation of the electric blower 14 and adjusting the suction force is disposed on the handle portion 13. The operation switch 17 is provided with a standard operation mode and a strong operation mode in which the rotation speed of the electric blower 14 is higher and the suction force is stronger than that in the standard operation mode.

[0016] When the operation switch of the operation switch 17 is operated, the electric blower 14 operates to generate suction force, dust is sucked from the suction nozzle body 30, passes through the extension pipe 20, and is collected in the dust collection chamber 12.

[0017] When not in use, the electric vacuum cleaner 1 is placed on a stand 50, and the secondary batteries 160 are charged.

[0018] FIG. 3 is a control block diagram of the electric vacuum cleaner according to an embodiment of the present invention. The vacuum cleaner main body 10 is provided with a control device 100 that controls the electric vacuum cleaner 1, such as the electric blower 14 and the secondary batteries 160.

[0019] The control device 100 includes a temperature detection unit 110 for detecting the temperature of the secondary battery 160, an ambient temperature detection unit 111 for detecting the ambient temperature, a voltage detection unit 120 for detecting the voltage of the secondary battery 160, a current detection unit 130 for detecting the current of the secondary battery 160, a determination unit 140 that determines the deterioration state of the secondary battery 160 based on the temperature of the secondary battery 160 detected by the temperature detection unit 110, the ambient temperature detected by the ambient temperature detection unit 111, the voltage of the secondary battery 160 detected by the voltage detection unit 120, and the current of the secondary battery 160 detected by the current detection unit 130, and determines whether or not to operate the electric blower 14 according to this determination result and the operation command from the operation switch 17, and a control unit 150 that controls the electric blower 14 based on the determination result of the determination unit 140. The vacuum cleaner 1 is also equipped with a display unit 18 for displaying information. The display unit 18 is provided, for example, on the handle unit 13. The control device 100 allows setting a standard operating mode and a high-power operating mode in which the rotation speed of the electric blower 14 is higher and the suction power is stronger than in the standard operating mode.

[0020] Next, the configuration of the determination unit 140 will be described. Figure 4 is a diagram showing the configuration of the battery model 131 within the determination unit 140 according to an embodiment of the present invention.

[0021] Battery model 131 consists of voltage model 132, temperature model 133, and degradation model 134.

[0022] Within the determination unit 140, a calculation unit (not shown) calculates the initial charge level (SOC) and initial degradation state (SOH) of the secondary battery 160 based on the voltage V, current I, and surface temperature T of the secondary battery 160, and stores them in the memory unit. The initial charge level (SOC) and initial degradation state (SOH) are input to the battery model 131.

[0023] The State of Charge (SOC) is generally calculated using the following formula (a).

[0024] State of Charge (SOC) (%) = (Remaining battery capacity Ah / Fully charged battery capacity Ah) × 100 …(a) Furthermore, the degradation rate SOH is generally calculated using the following formula (b).

[0025] Degradation rate SOH (%) = (Battery full charge capacity Ah at the time of degradation / Initial battery full charge capacity Ah) × 100 …(b) Voltage model 132 outputs the voltage of the secondary battery 160, the state of charge (SOC), the temperature change (heat generation) of the secondary battery 160, and the state of degradation (SOH) under any given degradation state.

[0026] In the temperature model 133, the amount of heat output from the voltage model 132 and the ambient temperature are input, and the temperature trend of the battery is output based on these.

[0027] In the degradation model 134, the degradation rate (SOH) of the secondary battery 160 is sequentially updated based on the state of charge (SOC), the load condition of the current I, and the temperature of the secondary battery 160, and output to the voltage model 132. Generally, the degradation rate (SOH) of a battery includes the capacity retention rate (SOHQ) and the resistance increase rate (SOHR). In this embodiment, the capacity retention rate (SOHQ) is used to set the voltage, and the resistance increase rate (SOHR) is used to set the temperature.

[0028] Voltage model 132 calculates the voltage behavior for the next time step based on this updated degradation rate (SOH). By performing such coupled simulations, the battery model ultimately outputs the battery voltage, state of charge (SOC), temperature changes, and degradation rate (SOH) (capacity retention rate (SOHQ), resistance increase rate (SOHR)). This configuration makes it possible to simulate the current waveform of an actual DC stick vacuum cleaner and the degradation and temperature changes from ambient temperature.

[0029] In this embodiment, to reproduce the battery voltage, the equivalent circuit model of the battery shown in Figure 4 was used as battery model 131. It was represented by an Open Circuit Voltage (OCV) component representing the electromotive force of the battery, a DC resistance component R0 representing the ohm resistance of the components constituting the battery, and polarization terms Vp1 and Vp2 representing the resistance due to ion diffusion and electroelectricity within the solid. The polarization terms are represented by a capacitor with polarization resistance Rp and time constant τ. The equivalent circuit model can be expressed as equations (1) and (2).

[0030]

number

[0031]

number

[0032] CCV is the Closed Circuit Voltage, T is the battery temperature, and t is time. Vp_z represents the previous value of polarization. Since OCV is a value that changes with the state of charge (SOC), SOC was used as the input. Since R0 and Rp are values ​​that change with the state of charge (SOC) and the battery temperature (T), the state of charge (SOC) and the battery temperature (T) were used as the inputs.

[0033] Battery heat generation Q battery Since this is determined by the resistance of the battery including the polarization term, we used equation (3).

[0034]

number

[0035] Temperature model 133 was created based on Newton's law of cooling. The heat balance equations are given by equations (4) to (6) below, and the temperature rise is given by equation (7).

[0036]

number

[0037]

number

[0038]

number

[0039]

number

[0040] Q total Q is the final heat generated by the battery. radiation is radiant heat, Q transfer σ is heat dissipation by heat transfer, σ is the Stefan-Boltzmann constant, ε is emissivity, S is surface area, T battery σ represents the battery temperature, Tm represents the refrigerant temperature, α represents the heat transfer coefficient, ΔT represents the temperature rise of the battery, and C represents the heat capacity of the battery. σ, ε, and C are values ​​that can be read from the specifications if the battery type and can material are known. Radiant heat from the battery cells is absorbed by the walls of the pack casing. Therefore, the value of radiant heat is determined by the surface area of ​​the outer wall of the pack casing, and is considered to be negligibly small from the perspective of the battery cells. For this reason, in this embodiment, Q radiation It was set to 0.

[0041] Degradation model 134 primarily calculates the capacity retention rate (SOHQ) and resistance rise rate (SOHR) based on conditions such as battery temperature, current, state of charge (SOC), and operating interval. The operating interval refers to how often (in days) the degradation simulation is calculated.

[0042] The overall flow of battery model 131 involves calculating the operating results for one day using voltage model 132 and temperature model 133, extracting representative values ​​from these results, sending them to degradation model 134, performing degradation calculations for a predetermined number of days, and returning the updated capacity retention rate (SOHQ) and resistance increase rate (SOHR) to voltage model 132. By repeating this a predetermined number of times, the degradation rate up to a specified number of years can be calculated.

[0043] The capacity retention rate SOHQ is the capacity retention rate SOHQ in a storage test strage and the capacity retention rate SOHQ in a cycle test cycle can be expressed as the sum, where a strage and a cycle are deterioration coefficients in the storage test and the cycle test, respectively, and vary depending on the battery used.

[0044] Equations (8) and (9) show the arithmetic expression for the capacity retention rate SOHQ and the arithmetic expression for the resistance increase rate SOHR.

[0045]

Mathematical Expression

[0046]

Mathematical Expression

[0047] In calculating the capacity retention rate SOHQ, the storage test and the cycle test are performed under various test conditions. First, the battery capacity deterioration rate coefficient a strage in the storage test is generalized. Deterioration caused by storage is subtracted from the cycle test results to obtain the battery capacity deterioration value from the cycle test, and the cycle deterioration coefficient a cycle is calculated from each cycle test result. Similarly for the resistance increase rate SOHR, changes in battery resistance are measured from the storage test and the cycle test, and b strage and b cycle are obtained and used as the deterioration calculation formula.

[0048] Next, the processing of the determination unit 140 will be described. FIG. 5 is a flowchart showing the processing content of the determination unit 140 according to an embodiment of the present invention.

[0049] In FIG. 5, when the vacuum cleaner is being charged, the determination unit 140 calculates the capacity retention rate SOHQ, estimates the resistance increase rate SOHR based on a pre-stored calculation formula, and stores the result (step S501).

[0050] When the user inputs the ON operation switch of the vacuum cleaner 1 from the operation switch 17 (step S502), the determination unit 140 determines whether the input operation switch is in high-power operation mode or not (step S503).

[0051] If the operating switch is in high-power mode (Yes in step S503), the determination unit 140 calculates the time until the lower limit set voltage is reached from the pre-stored discharge curve and capacity retention rate SOHQ, and the time until the upper limit set temperature is reached from the resistance rise rate SOHR, and displays the shorter of the two times on the display unit 18 (step S504). The shorter of the two times displayed on the display unit 18 becomes the operating time of the vacuum cleaner 1 (electric blower 14). Then, if the secondary battery 160 reaches the lower limit set voltage or the upper limit set temperature, the determination unit 140 transmits this information to the control unit 150, and the control unit 150 stops the operation of the vacuum cleaner 1 (electric blower 14) (step S506). The discharge curve is created by plotting multiple values ​​of the capacity retention rate SOHQ against the number of charge-discharge cycles and connecting these values, and is a value that can be arbitrarily set by the user or manufacturer. The discharge curve is stored in advance in the memory of the determination unit 140.

[0052] If the operating switch is not in high-power mode (No. in step S503), i.e., in standard operating mode, the determination unit 140 calculates the time until the lower limit voltage is reached from the pre-stored discharge curve and capacity retention rate SOHQ, and displays it on the display unit 18 (step S505). The time displayed on the display unit 18 is the operating time of the vacuum cleaner 1 (electric blower 14).

[0053] Then, if the secondary battery 160 reaches the lower limit set voltage, the determination unit 140 transmits that information to the control unit 150, and the control unit 150 stops the operation of the vacuum cleaner 1 (electric blower 14) (step S506).

[0054] After the operation of the vacuum cleaner 1 (electric blower 14) is stopped, the determination unit 140 determines whether or not the secondary battery 160 has reached the lower limit set voltage (step S507). If the secondary battery 160 has reached the lower limit set voltage and the operation of the vacuum cleaner 1 (electric blower 14) has stopped (Yes in step S507), the determination unit 140 displays on the display unit 18 that the secondary battery 160 has no remaining charge (step S508).

[0055] If the secondary battery 160 has not reached the lower limit set voltage (No in step S507), the determination unit 140 determines whether or not the secondary battery 160 has reached the upper limit set temperature (step S509). If the secondary battery 160 has reached the upper limit set temperature and the operation of the vacuum cleaner 1 (electric blower 14) has stopped (Yes in step S509), the determination unit 140 displays on the display unit 18 that the temperature of the secondary battery 160 is high (step S510).

[0056] If the secondary battery 160 has not reached the upper limit set temperature (No. in step S511), the determination unit 140 stops the vacuum cleaner 1 (electric blower 14) normally without displaying a warning on the display unit 18 (step S511).

[0057] Figure 6 shows the relationship between operating time, upper limit temperature, and lower limit voltage when the capacity retention rate (SOHQ) is 100%. Figure 7 shows the relationship between operating time, upper limit temperature, and lower limit voltage when the capacity retention rate (SOHQ) is 90%. Figures 6 and 7 show the operating conditions in high-power mode.

[0058] In Figures 6 and 7, the vertical axis shows the temperature and voltage of the secondary battery 160, and the horizontal axis shows the operating time of the vacuum cleaner 1 (electric blower 14).

[0059] In the determination unit 140, an upper temperature limit and a lower voltage limit are set to protect the secondary battery 160. In this embodiment, the upper temperature limit is set based on the capacity retention rate SOHQ, and the lower voltage limit is set based on the resistance rise rate SOHR.

[0060] When power is supplied from the secondary battery 160 and the vacuum cleaner 1 (electric blower 14) starts operating, the battery temperature (1) of the secondary battery 160 rises and the battery voltage (1) of the secondary battery 160 decreases. In the example shown in Figure 6, where the capacity retention rate SOHQ is 100%, the battery voltage (1) of the secondary battery 160 reaches the lower limit voltage faster than the time it takes for the battery temperature (1) to reach the upper limit voltage. Therefore, the time it takes for the battery voltage (1) of the secondary battery 160 to reach the lower limit voltage is estimated, and the operating time of the vacuum cleaner 1 (electric blower 14) is displayed on the display unit 18.

[0061] Furthermore, in the example shown in Figure 7, where the capacity retention rate (SOHQ) is 90%, the battery temperature (2) of the secondary battery 160 reaches the upper limit set temperature faster than the time it takes for the battery voltage (2) to reach the lower limit set voltage. Therefore, the time it takes for the battery temperature (2) of the secondary battery 160 to reach the upper limit set temperature is estimated, and the operating time of the vacuum cleaner 1 (electric blower 14) is displayed on the display unit 18.

[0062] The effects of this embodiment will be explained. Figure 8 shows a comparison between this embodiment and a comparative example. In this embodiment, the remaining operating time is estimated using battery voltage and the remaining operating time is estimated using battery temperature.

[0063] In this embodiment (1), the error in remaining operating time is 3% when the capacity retention rate (SOHQ) is 100%. Similarly, in comparative example (1), the error in remaining operating time is also 3%, just like in this embodiment (1).

[0064] Next, in this embodiment (2), when the capacity retention rate SOHQ is 90%, it is estimated that the battery temperature (2) will reach the upper limit set temperature before the battery voltage (2) reaches the lower limit set voltage, so the error in remaining operating time is 3%.

[0065] In Comparative Example (2), when the capacity retention rate (SOHQ) is 90%, only the time to reach the lower limit voltage is estimated, resulting in a 15% error in the remaining operating time. In other words, in Comparative Example (2), the battery temperature (2) reaches the upper limit temperature in a shorter time than the estimated operating time, resulting in a 15% error in the remaining operating time. As secondary batteries degrade, their internal resistance increases, making them more susceptible to temperature increases.

[0066] In this embodiment (2), it is estimated that the battery temperature (2) will reach the upper limit set temperature before the battery voltage (2) reaches the lower limit set voltage, and this time is displayed as the operating time. Therefore, even when the electric blower 14 is operated in high-speed mode while the secondary battery is degraded, the operating time can be determined with less error, improving the operability of the vacuum cleaner.

[0067] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations. [Explanation of Symbols]

[0068] 1…Electric vacuum cleaner, 10…Vacuum cleaner body, 11…Dust collection cover, 12…Dust collection chamber, 13…Handle, 14…Electric blower, 16…Battery pack, 17…Operation switch, 18…Display unit, 20…Extension tube, 30…Suction nozzle, 40…Brush unit, 50…Stand, 100…Control device, 110…Temperature detection unit, 111…Ambient temperature detection unit, 120…Voltage detection unit, 130…Current detection unit, 131…Battery model, 132…Voltage model, 133…Temperature model, 134…Degradation model, 140…Determination unit, 150…Control unit, 160…Secondary battery

Claims

1. In an electric vacuum cleaner comprising an electric blower that generates suction force, a secondary battery that supplies power to the electric blower, and a control device that controls the electric blower and the secondary battery, The control device can be set to a standard operating mode and a high-speed operating mode in which the rotational speed of the electric blower is higher than that of the standard operating mode. When the aforementioned high-power operation mode is set, the operating time of the electric blower is set to the shorter of either the time it takes for the battery voltage of the secondary battery to reach the lower limit set voltage, or the time it takes for the battery temperature of the secondary battery to reach the upper limit set temperature, and the operating time is displayed on the display unit.

2. In the vacuum cleaner according to claim 1, The control device, when the standard operating mode is set, determines the time it takes for the battery voltage of the secondary battery to reach the lower limit set voltage as the operating time of the electric blower, and displays the operating time on the display unit, thereby enabling the operation of the electric blower.

3. In the vacuum cleaner according to claim 1 or 2, The control device is characterized by calculating the time it takes for the battery voltage of the secondary battery to reach a lower limit set voltage based on the capacity retention rate (SOHQ) of the secondary battery.

4. In the vacuum cleaner according to claim 3, The control device is characterized by calculating the time it takes for the battery temperature of the secondary battery to reach the upper limit set temperature based on the resistance rise rate SOHR of the secondary battery.

5. In the vacuum cleaner according to claim 4, The aforementioned display unit is provided on the handle that the user holds when cleaning, characterized in that it is located on the handle.

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