Battery maintenance system, battery maintenance method, and refilling device

Abstract

Provided is a battery maintenance system comprising: a supply path for supplying a liquid to a battery; a first on-off valve provided on the supply path; and a second on-off valve provided downstream of the first on-off valve in a supply direction of the liquid on the supply path.

Description

Battery maintenance system, battery maintenance method and replenishing device

[0001] The present disclosure relates to a battery maintenance system, a battery maintenance method, and a replenishment device.

[0002] Japanese Patent Application Laid-Open Publication No. 2021-165057 discloses an automatic battery water replenishment device that replenishes battery fluid. In this automatic battery water replenishment device, when water is filled to the full capacity twice in a row, a correction is made to match the amount of water lost due to charging after the full capacity replenishment with the amount of water replenishment due to the actual water filling time after the water loss, and control is performed to end water filling after the full capacity correction process and the non-full capacity correction process.

[0003] The present disclosure aims to improve the maintainability of batteries.

[0004] A battery maintenance system of a first aspect of the present disclosure comprises a supply path that supplies liquid to a battery, a first on-off valve provided on the supply path, and a second on-off valve provided on the supply path downstream of the first on-off valve in the supply direction of the liquid.

[0005] In the battery maintenance system of the first aspect, by opening both the first and second on-off valves, fluid is supplied to the battery through the supply path. Here, in the battery maintenance system, even if a malfunction occurs in the second on-off valve during supply of fluid to the battery, the supply of fluid to the battery can be stopped by closing the first on-off valve, which is located upstream of the second on-off valve in the fluid supply direction. This makes it possible to prevent excessive fluid supply to the battery. By preventing excessive fluid supply to the battery in this way, an increase in the frequency of maintenance due to fluid overflow is suppressed, improving the maintainability of the battery.

[0006] A battery maintenance system of a second aspect of the present disclosure is the battery maintenance system of the first aspect, wherein the first opening / closing valve is an electrically driven valve, and further includes a control unit that controls the driving of the first opening / closing valve.

[0007] In the battery maintenance system of the second aspect, the control unit controls the driving (opening and closing) of the first on-off valve, which reduces the burden on the operator compared to when the operator manually drives the first on-off valve.

[0008] A battery maintenance system of a third aspect of the present disclosure is the battery maintenance system of the second aspect, further comprising a charging cable connecting a charger to the battery, and the control unit controls the start and stop of charging the battery.

[0009] In the battery maintenance system of the third aspect, the control unit controls the start and stop of charging the battery by the charger. Therefore, the battery maintenance system can reduce the burden on the worker compared to when the worker performs charging work including starting and stopping charging the battery by himself.

[0010] A battery maintenance system according to a fourth aspect of the present disclosure is the battery maintenance system according to the third aspect, wherein the control unit simultaneously performs charging of the battery and supply of the liquid.

[0011] In the battery maintenance system of the fourth aspect, the control unit simultaneously charges the battery and supplies the battery with electrolyte, which reduces the time required to charge the battery and supply the electrolyte compared to when charging the battery and supplying the electrolyte separately.

[0012] A battery maintenance system according to a fifth aspect of the present disclosure is the battery maintenance system according to the third aspect, wherein the control unit supplies the liquid after or before charging the battery.

[0013] In the battery maintenance system of the fifth aspect, the control unit supplies the battery with fluid after or before charging. Here, depending on the condition and type of the battery, it may be preferable to supply fluid to the battery after or before charging. Therefore, in the battery maintenance system, by supplying fluid to the battery after or before charging depending on the battery condition, it is possible to extend the battery life.

[0014] A sixth aspect of the battery maintenance system of the present disclosure is a battery maintenance system according to any one of the second to fifth aspects, wherein the control unit calculates the amount of liquid to be supplied to the battery based on the charging and discharging history of the battery, and keeps the first opening / closing valve open until the calculated amount of liquid is supplied to the battery.

[0015] In the battery maintenance system of the sixth aspect, the control unit calculates the amount of fluid to be supplied to the battery based on the battery's charge / discharge history. The control unit then keeps the first on-off valve open until the calculated amount of fluid is supplied to the battery. Therefore, the battery maintenance system can more efficiently supply any shortage of fluid to the battery than when a constant amount of fluid is always supplied to the battery regardless of the battery's charge / discharge history.

[0016] A seventh aspect of the battery maintenance system of the present disclosure is the battery maintenance system of the sixth aspect, wherein the battery is composed of a plurality of cells, and the second opening / closing valve is in an open state when the liquid level of the stored liquid stored in at least one of the cells is less than a first threshold value, and is in a closed state when the liquid level is equal to or greater than the first threshold value.

[0017] In the battery maintenance system of the seventh aspect, when supplying liquid to the battery, the second on-off valve remains open until the liquid level of the stored liquid in at least one cell reaches a first threshold. When the liquid level reaches or exceeds the first threshold, the second on-off valve closes, and the supply of liquid to the battery is stopped. Here, in the battery maintenance system, if the first threshold is set to a liquid level that can prevent excessive supply of liquid to the battery, it is possible to further prevent an increase in the frequency of maintenance due to liquid overflow.

[0018] The battery maintenance system of the eighth aspect of the present disclosure is the battery maintenance system of the seventh aspect, further comprising a liquid level sensor that detects the liquid level of the stored liquid, and the control unit closes the first opening / closing valve when the liquid level detected by the liquid level sensor is equal to or greater than a second threshold value that is greater than the first threshold value.

[0019] In the battery maintenance system of the eighth aspect, when the height of the liquid level detected by the liquid level sensor is equal to or greater than a second threshold value that is greater than the first threshold value, the control unit closes the first on-off valve. Here, in the battery maintenance system described above, if an upper limit value for preventing liquid from overflowing from the cell is set to the second threshold value, for example, even if a malfunction occurs in the second on-off valve, the control unit closes the first on-off valve when the height of the liquid level reaches or exceeds the second threshold value, thereby effectively preventing liquid from overflowing due to an excessive supply of liquid to the battery.

[0020] A ninth aspect of the battery maintenance system of the present disclosure is the battery maintenance system of the seventh aspect, further comprising a liquid level sensor that detects the liquid level of the stored liquid, and the control unit maintains the first opening / closing valve in an open state when the liquid level detected by the liquid level sensor is less than a third threshold value that is smaller than the first threshold value.

[0021] In a ninth aspect of the battery maintenance system, when the liquid level detected by the liquid level sensor is less than a third threshold value that is smaller than the first threshold value, the control unit keeps the first on-off valve open. Here, in the above battery maintenance system, if the lower limit for preventing the cells from running out of liquid is set to the third threshold value, and the amount of liquid supplied is small and the liquid level does not reach the third threshold value, the control unit keeps the first on-off valve open, thereby preventing the cells from running out of liquid.

[0022] A battery maintenance system of a tenth aspect of the present disclosure is a battery maintenance system of the ninth aspect, wherein the control unit maintains the first opening / closing valve in an open state when the liquid level detected by the liquid level sensor is below a fourth threshold value set between the first threshold value and the third threshold value.

[0023] In a battery maintenance system of a tenth aspect, when the liquid level detected by the liquid level sensor is equal to or less than a fourth threshold value set between the first threshold value and the third threshold value, the control unit keeps the first on-off valve open. Here, in the battery maintenance system, when the optimal value for the liquid level in the cell is set to the fourth threshold value, the control unit keeps the first on-off valve open until the supply of liquid reaches the fourth threshold value, so that it is possible to supply liquid up to the optimal value while suppressing liquid overflow due to an excessive supply of liquid to the battery.

[0024] An eleventh aspect of the battery maintenance system of the present disclosure is the battery maintenance system of the sixth aspect, wherein the battery is composed of a plurality of cells, the supply path branches into a plurality of paths along the way to supply the liquid to each of the cells, the first on-off valve is provided upstream of the branched portion of the supply path in the supply direction, and the second on-off valve is provided in each of a plurality of branch paths that form a portion of the supply path downstream of the branched portion in the supply direction.

[0025] In the battery maintenance system of the eleventh aspect, since the supply path branches into multiple branch paths, the amount of liquid supplied to each cell varies depending on the distance of each branch path, etc. However, since the multiple branch paths are each provided with a second on-off valve, if the supply of liquid to any cell becomes excessive, the supply of liquid to the cell can be stopped by closing the second on-off valve corresponding to the excess cell. In this way, the battery maintenance system can suppress excessive supply of liquid to each cell that constitutes the battery compared to when the second on-off valve is provided upstream in the supply direction from the branch point of the supply path.

[0026] A battery maintenance system of a twelfth aspect of the present disclosure is the battery maintenance system of the eleventh aspect, wherein each of the second opening / closing valves is in an open state when the liquid level of the stored liquid in each of the cells is less than a first threshold value, and is in a closed state when the liquid level is equal to or greater than the first threshold value.

[0027] In the battery maintenance system of the twelfth aspect, when supplying fluid to the battery, if the fluid level in each cell is less than a first threshold, the second on-off valve corresponding to each cell is opened. If the fluid level in each cell is equal to or greater than the first threshold, the second on-off valve corresponding to each cell is closed, and the supply of fluid to each cell is stopped. Here, in the battery maintenance system, if the first threshold is set to a fluid level that can prevent excessive supply of fluid to the battery, it is possible to further prevent an increase in the frequency of maintenance due to fluid overflow.

[0028] A thirteenth aspect of the battery maintenance system of the present disclosure is the battery maintenance system of the twelfth aspect, further comprising a liquid level sensor that detects the liquid level of the stored liquid, the liquid level sensor being installed in two or more of the cells, and the control unit closing the first opening / closing valve when the liquid level detected by at least one of the liquid level sensors is equal to or greater than a second threshold value that is greater than the first threshold value.

[0029] In a battery maintenance system of a thirteenth aspect, a liquid level sensor is installed in each of two or more cells, and when the liquid level detected by at least one liquid level sensor is equal to or greater than a second threshold value that is greater than the first threshold value, the control unit closes the first on-off valve. Here, in the battery maintenance system, if an upper limit value for preventing liquid from overflowing from the cells is set to the second threshold value, for example, even if a malfunction occurs in the second on-off valve, the control unit closes the first on-off valve when the liquid level reaches or exceeds the second threshold value, thereby effectively preventing liquid from overflowing due to an excessive supply of liquid to the battery.

[0030] A battery maintenance system of a fourteenth aspect of the present disclosure is the battery maintenance system of the thirteenth aspect, wherein the plurality of cells are stored in parallel in a metal storage box, and the liquid level sensor is installed on a first cell of the plurality of cells that has the largest number of contact surfaces with the storage box, and a second cell that has the smallest number of contact surfaces with the storage box.

[0031] In a fourteenth aspect of the battery maintenance system, a liquid level sensor is installed in each of the first and second cells. The second cell, which has the fewest contact surfaces with the metal housing, is more likely to become hot than the first cell, which has the most contact surfaces with the housing, because it is more difficult or unable to dissipate heat through the housing. Therefore, the stored liquid in the second cell decreases more quickly than in the first cell. Therefore, by installing liquid level sensors in the second cell, which decreases the stored liquid quickly, and the first cell, which decreases the stored liquid slowly, it is possible to supply liquid to the second cell according to the decrease in the stored liquid, and to stop the supply of liquid according to the overflow of the stored liquid in the first cell.

[0032] A battery maintenance system of a fifteenth aspect of the present disclosure is the battery maintenance system of the fourteenth aspect, wherein the control unit opens the first opening / closing valve when the liquid level detected by the liquid level sensor installed in the second cell is less than a third threshold value that is smaller than the first threshold value, and closes the first opening / closing valve when the liquid level detected by the liquid level sensor installed in the first cell is equal to or greater than a second threshold value that is larger than the first threshold value.

[0033] In a fifteenth aspect of the battery maintenance system, the control unit opens the first on-off valve when the liquid level detected by the liquid level sensor installed in the second cell, where the stored liquid decreases quickly, is below a third threshold value that is smaller than the first threshold value. In the battery maintenance system, if the lower limit for preventing the cell from running out is set to the third threshold value, the control unit keeps the first on-off valve open when the supply of liquid is low and the liquid level does not reach the third threshold value, thereby preventing the second cell from running out. In the battery maintenance system, if the liquid level detected by the liquid level sensor installed in the first cell, where the stored liquid decreases slowly, is equal to or greater than a second threshold value that is larger than the first threshold value, the control unit closes the first on-off valve. In the battery maintenance system, if the upper limit for preventing liquid from overflowing from the cell is set to the second threshold value, for example, even if a malfunction occurs in the second on-off valve, the control unit closes the first on-off valve when the liquid level reaches or exceeds the second threshold value, thereby effectively preventing liquid overflow due to excessive supply of liquid to the battery (e.g., liquid overflow from the first cell).

[0034] A battery maintenance system of a 16th aspect of the present disclosure is a battery maintenance system of either the 7th or 12th aspect, wherein the second opening / closing valve comprises a float that floats on the liquid, and a valve body that moves in conjunction with the float and contacts a valve seat to block the internal flow path when the height of the liquid level is equal to or higher than a first threshold value.

[0035] In the battery maintenance system of the sixteenth aspect, the valve element that moves in conjunction with the float contacts the valve seat and closes the internal flow path when the liquid level is equal to or higher than the first threshold. In this way, compared to when an electrically driven valve element is used as the second on-off valve, it is possible to suppress increases in costs related to control of the second on-off valve.

[0036] A battery maintenance system of a seventeenth aspect of the present disclosure is the battery maintenance system of the seventh or twelfth aspect, further comprising a catalyst unit that reduces gas produced by electrolysis of the stored liquid and returns it to the liquid.

[0037] In the battery maintenance system of the seventeenth aspect, the catalyst reduces gas generated by electrolysis of the stored liquid and returns it to the liquid, which allows the rate at which the stored liquid decreases to be slower than in a battery maintenance system without a catalyst.

[0038] The battery maintenance system of an eighteenth aspect of the present disclosure is the battery maintenance system of the seventeenth aspect, wherein the catalyst section is connected to the second on-off valve.

[0039] In the battery maintenance system of the eighteenth aspect, the catalyst unit is connected to the second on-off valve, so the cell structure can be simplified compared to when the catalyst unit is provided in a location separate from the second on-off valve in the cell.

[0040] A battery maintenance system according to a nineteenth aspect of the present disclosure is the battery maintenance system according to the eleventh aspect, wherein the supply path is releasably connected between the branch portion and the first opening / closing valve by a joint mechanism.

[0041] In the battery maintenance system of the nineteenth aspect, the branched portion of the supply path and the first on-off valve are releasably connected by a joint mechanism. Here, in the battery maintenance system described above, compared to a case in which the joint mechanism is provided downstream of the branched portion of the supply path in the supply direction, fewer parts need to be connected and disconnected, making it easier to connect the supply path. This reduces the burden on the operator.

[0042] A battery maintenance method according to a twentieth aspect of the present disclosure combines charging and supplying a liquid to a battery.

[0043] In the battery maintenance method of the twentieth aspect, since the charging of the battery and the supply of the electrolyte are performed simultaneously, the time required for charging the battery and the supply of the electrolyte can be shortened compared to when the charging of the battery and the supply of the electrolyte are performed separately, thereby improving the ease of maintenance of the battery.

[0044] A battery maintenance method according to a twenty-first aspect of the present disclosure is the battery maintenance method according to the twentieth aspect, in which the supply of the liquid is carried out from the start to the completion of supply between the start and completion of charging of the battery.

[0045] In the battery maintenance method of the 21st aspect, the supply of liquid is performed from start to finish between the start and completion of charging the battery. That is, in the battery maintenance method, the supply of liquid to the battery can be started and finished while the battery is being charged, which further reduces the time required to charge the battery and supply the liquid. This further improves the ease of maintenance of the battery.

[0046] A battery maintenance method according to a twenty-second aspect of the present disclosure is the battery maintenance method according to the twenty-first aspect, wherein the supply of the liquid is completed before the voltage of the battery reaches a predetermined voltage.

[0047] In the battery maintenance method of the 22nd aspect, for example, if the predetermined voltage is set to a voltage lower than the voltage at which gassing occurs, the supply of liquid can be completed before the battery voltage reaches the predetermined voltage, thereby preventing the supply of liquid from being affected by the occurrence of gassing.

[0048] A refilling device of a 23rd aspect of the present disclosure includes a supply path that supplies liquid to a battery, a first opening / closing valve provided on the supply path, and a second opening / closing valve provided on the supply path downstream of the first opening / closing valve in the supply direction of the liquid.

[0049] In the refilling device of the 23rd aspect, by opening both the first and second valves, the liquid is supplied to the battery through the supply path. Here, even if a malfunction occurs in the second valve during supply of liquid to the battery, the supply of liquid to the battery can be stopped by closing the first valve, which is located upstream of the second valve in the liquid supply direction. This prevents excessive liquid from being supplied to the battery. By preventing excessive liquid from being supplied to the battery in this way, an increase in the frequency of maintenance due to liquid overflow is suppressed, improving the maintainability of the battery.

[0050] A replenishment device of a 24th aspect of the present disclosure is the replenishment device of the 23rd aspect, wherein the first on-off valve is an electrically driven valve, and further includes a control unit that controls the driving of the first on-off valve.

[0051] In the refilling device of the twenty-fourth aspect, the control unit controls the actuation (opening and closing) of the first on-off valve, which reduces the burden on the operator compared to when the operator manually operates the first on-off valve.

[0052] A 25th aspect of the present disclosure is a replenishment device that, in the 24th aspect, further includes a charger and a charging cable connecting the charger and the battery, and the control unit controls the start and stop of charging the battery.

[0053] In the refilling device of the twenty-fifth aspect, the control unit controls the start and stop of charging the battery, which reduces the burden on the worker compared to when the worker performs charging work including starting and stopping charging the battery.

[0054] A replenishment device of a 26th aspect of the present disclosure is a replenishment device of any one of the 23rd to 25th aspects, further comprising a storage section that is provided in the supply path upstream of the first opening / closing valve in the supply direction of the liquid and that stores the liquid.

[0055] The refilling device of the 26th aspect is provided with a storage section for storing liquid, and therefore, for example, by storing liquid that has undergone a predetermined process in the storage section, maintenance time can be shortened.

[0056] According to the present disclosure, it is possible to improve the maintainability of the battery.

[0057] 1 is a diagram showing a schematic configuration of a battery maintenance system according to an embodiment of the present disclosure. FIG. 2 is a block diagram showing the configuration of a control system of the battery maintenance system according to an embodiment of the present disclosure. FIG. 3 is a schematic plan view of a battery to which liquid is supplied by the battery maintenance system according to an embodiment of the present disclosure. FIG. 4 is a cross-sectional view showing the configurations of a first cell, a second on-off valve, and a first liquid level sensor used in the battery maintenance system according to an embodiment of the present disclosure. FIG. 5 is a cross-sectional view showing the configurations of a second cell, a second on-off valve, and a second liquid level sensor used in the battery maintenance system according to an embodiment of the present disclosure. FIG. 6 is a flowchart showing a flow of supplying liquid to a battery using the battery maintenance system according to an embodiment of the present disclosure. FIG. 7 is a diagram showing the timing of charging and liquid supply to a battery. FIG. 8 is a cross-sectional view showing a configuration when a return flow is connected to the first cell and the second on-off valve used in the battery maintenance system according to an embodiment of the present disclosure. FIG. 9 is a diagram showing a schematic configuration of a battery maintenance system according to another embodiment of the present disclosure. FIG. 10 is a schematic plan view of a battery according to a modified example. FIG. 11 is a schematic plan view of a battery to which liquid is supplied by the battery maintenance system according to another embodiment of the present disclosure. FIG. 12 is a diagram showing a schematic configuration of a battery maintenance system according to another embodiment of the present disclosure. FIG. 13 is a diagram showing a forklift as an example of a mobile body equipped with a battery according to the present disclosure.

[0058] An embodiment of the present disclosure will be described below with reference to the drawings. In each drawing, the same or equivalent components and parts are designated by the same reference numerals. Furthermore, the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0059] As shown in Figure 1, a battery maintenance system 10 (hereinafter referred to as "system 10") of this embodiment is a system that has the function of supplying liquid (hereinafter referred to as "liquid supply") to a battery 110. In the figure, the liquid to be supplied to the battery 110 is indicated by the symbol FL. Also in the figure, the stored liquid stored in a cell 112 is indicated by the symbol RL.

[0060] Before describing the system 10, the battery 110 to which the liquid FL is supplied by the system 10 will be described.

[0061] As shown in FIG. 3 , the battery 110 is a lead-acid battery composed of a plurality of cells 112. The plurality of cells 112 are housed in parallel in a metal housing 114. Specifically, the housing 114 is a rectangular box, and the plurality of cells 112 are arranged in a matrix on the bottom surface of the housing 114. In the present embodiment, as an example, the plurality of cells 112 are arranged in a matrix of four rows and four columns on the bottom surface of the housing 114. Furthermore, of the plurality of cells 112, the cells 112 located on the periphery are supported in position by contacting a side wall 114 a of the housing 114. In this manner, the parallel state of the plurality of cells 112 is maintained by the side wall 114 a of the housing 114.

[0062] In this embodiment, the cell 112 has a voltage of, for example, 2 V when fully charged. The cells 112 are connected in series, but may also be connected in parallel.

[0063] Furthermore, of the multiple cells 112, the cell with the largest number of contact surfaces with the storage box 114 is referred to as the first cell 112a, and the cell with the smallest number of contact surfaces with the storage box 114 is referred to as the second cell 112b. In this embodiment, of the multiple cells 112, the cell 112 located on the outer periphery and at the corner is the first cell 112a. The first cell 112a contacts two surfaces of the side wall 114a of the storage box 114 and the bottom surface, a total of three surfaces. Of the multiple cells 112, the cell 112 located on the inner side is the second cell 112b. The second cell 112b contacts the bottom surface of the storage box 114 but does not contact the side wall 114a. Therefore, the second cell 112b contacts one surface with the storage box 114.

[0064] 1, the first cell 112a and the second cell 112b are adjacent to each other, but this is for convenience of explanation only and differs from the actual cell arrangement. Also, the terminals of the adjacent first cell 112a and second cell 112b are connected, but this is also for convenience of explanation only and differs from the actual inter-cell terminal connection.

[0065] Next, the system 10 will be described. As shown in Fig. 1, the system 10 includes a supply path 20, a first on-off valve 30, and a second on-off valve 40. The system 10 of this embodiment also includes, as an example, a liquid level sensor 50 and a control unit 60.

[0066] The supply path 20 is a flow path that supplies the liquid FL to the battery 110. In this embodiment, as an example, the liquid FL supplied to the battery 110 is purified water, and the stored liquid RL stored in the cells 112 of the battery 110 is battery fluid. However, the present disclosure is not limited to this configuration. For example, the liquid FL may be water containing more impurities than purified water (tap water, for example), or it may be battery fluid. Examples of battery fluid include dilute sulfuric acid (sulfuric acid + water). The specific gravity of dilute sulfuric acid is, for example, 1.1 to 1.3 at a temperature of 20°C. The battery fluid may contain additives such as inorganic salts and organic salts. When the liquid FL is dilute sulfuric acid, it may have the same concentration (specific gravity) as the stored liquid RL, or it may have a different concentration (specific gravity).

[0067] Furthermore, as an example, the supply path 20 of this embodiment supplies the liquid FL from a storage section 14 that stores the liquid FL to the battery 110. This storage section 14 is a container that stores the liquid FL and is located upstream of the first on-off valve 30 in the supply direction of the liquid FL. The supply direction of the liquid FL (hereinafter referred to as the "liquid supply direction") is the direction indicated by the arrow SD in Fig. 1. In this embodiment, the upstream end of the supply path 20 is connected to the storage section 14, but the present disclosure is not limited to this configuration, and for example, the upstream end of the supply path 20 may be connected to a water supply.

[0068] Moreover, as an example, the supply path 20 of the present embodiment branches into a plurality of paths midway to supply the liquid FL to each of the cells 112. Specifically, the supply path 20 branches into a plurality of branch paths 22 midway, and the plurality of branch paths 22 that form the portion downstream of the branched portion in the liquid supply direction supply the liquid FL to each of the cells 112.

[0069] The first on-off valve 30 is provided on the supply path 20. The first on-off valve 30 is an electrically driven valve, i.e., a valve that is electrically driven to open and close. The first on-off valve 30 is, for example, a solenoid valve, but is not limited to this. In addition, the first on-off valve 30 of this embodiment is, for example, provided upstream of the branching portion of the supply path 20 in the liquid supply direction.

[0070] The second on-off valve 40 is provided on the supply path 20 downstream in the liquid supply direction from the first on-off valve 30. In addition, the second on-off valve 40 of the present embodiment is provided in each of the plurality of branch paths 22, as an example.

[0071] Each second on-off valve 40 is in an open state when the height of the liquid level LS of the stored liquid RL stored in the corresponding cell 112 (hereinafter referred to as the “liquid level height”) is less than a first threshold value T1, and is in a closed state when the height is equal to or greater than the first threshold value T1. Note that the height of the liquid level LS of the stored liquid RL here refers to the height from the bottom surface of the cell 112.

[0072] The second on-off valve 40 of this embodiment, for example, includes a float 42 that floats on the stored liquid RL and a valve element 44 that moves in conjunction with the float 42 and contacts a valve seat 45 to close the internal flow path 48 when the liquid level of the stored liquid RL is equal to or higher than a first threshold. Specifically, as shown in FIG. 4 , the second on-off valve 40 includes a housing 46. The interior of the housing 46 forms a portion of the supply path 20 (branch path 22). The housing 46 includes a guide hole 47 that guides a shaft member 43 extending from the float 42. This guide hole 47 allows the float 42 to move up and down in response to the rise and fall of the liquid level LS. The valve element 44 is also provided on the shaft member 43 opposite the float 42. Because the float 42 and valve element 44 are provided on the shaft member 43 in this manner, the valve element 44 moves up and down in conjunction with the up and down movement of the float 42. Furthermore, the valve element 44 is pushed up by the shaft 43 to a predetermined height within the housing 46, whereby it contacts the valve seat 45 and blocks the internal flow path 48 that constitutes part of the supply path 20 (branch path 22). That is, as the liquid level LS rises, the float 42 rises, pushing the valve element 44 up via the shaft 43, blocking the internal flow path 48 of the housing 46 and stopping the supply of the liquid FL to the cell 112. Here, the height of the liquid level LS at which the valve element 44 contacts the valve seat 45 and blocks the internal flow path 48 is the first threshold value T1. Note that even if the liquid level LS exceeds the first threshold value T1, the contact state between the valve element 44 and the valve seat 45 does not change, and therefore the closed state of the internal flow path 48 is maintained. Furthermore, the first threshold value T1 of the second on-off valve 40 may be set for each cell 112.

[0073] The liquid level sensor 50 has a function of detecting the liquid level LS of the stored liquid RL. The liquid level sensor 50 may be installed in two or more cells 112. As an example, the liquid level sensor 50 of this embodiment is installed in at least one first cell 112a and at least one second cell 112b. As shown in FIG. 4, the liquid level sensor 50 installed in the first cell 112a will be referred to as the first liquid level sensor 50a below as appropriate. As shown in FIG. 5, the liquid level sensor 50 installed in the second cell 112b will be referred to as the second liquid level sensor 50b below as appropriate. The detection results of each liquid level LS by each liquid level sensor 50 are transmitted to the control unit 60.

[0074] As an example, the liquid level sensor 50 of this embodiment is a sensor that detects the liquid level LS in the cell 112 in which it is installed by being conductive when the liquid level detection unit 51 is immersed in the stored liquid RL and being non-conductive when the liquid level detection unit 51 is not immersed in the stored liquid RL. Note that the liquid level sensor 50 can adjust the vertical position of the liquid level LS to be detected (liquid level height) by adjusting the vertical position of the liquid level detection unit 51 relative to the cell 112. For example, by installing multiple liquid level sensors 50 in one cell 112 and varying the vertical positions of each liquid level detection unit 51, it becomes possible to precisely grasp the vertical position of the liquid level LS relative to the cell 112.

[0075] 4, the liquid level detection unit 51a of the first liquid level sensor 50a is disposed at a position where it can detect a second threshold value T2, which is greater (higher) than the first threshold value T1, in the first cell 112a. In this embodiment, as an example, the second threshold value T2 is set to an upper limit value for preventing liquid from overflowing from the first cell 112a. The two-dot chain line in FIG. 4 indicates the third threshold value T3 in the second cell 112b.

[0076] 5, the liquid level detection unit 51b of the second liquid level sensor 50b is disposed at a position where it can detect a liquid level in the second cell 112b at a third threshold value T3 that is smaller (lower) than the first threshold value T1. In this embodiment, as an example, the third threshold value T3 is set to a lower limit value for preventing the second cell 112b from running dry. Note that the two-dot chain line shown in FIG. 5 indicates the second threshold value T2 in the first cell 112a.

[0077] Here, the first cell 112a, which has the largest number of contact surfaces with the metal storage box 114, dissipates heat easily through the storage box. On the other hand, the second cell 112b, which has the smallest number of contact surfaces with the storage box 114, is not in contact with the storage box 114 compared to the first cell 112a, and therefore dissipates less heat through the storage box 114. Therefore, the second cell 112b is more likely to become hot and the stored liquid RL decreases more quickly than the first cell 112a. In this way, in the second cell 112b, which decreases the stored liquid RL most quickly, the liquid level detection unit 51b of the second liquid level sensor 50b is positioned at a position where the third threshold value T3, which serves as a lower limit for preventing the second cell 112b from running dry, can be detected. Therefore, when the liquid level height becomes equal to or greater than the third threshold value T3, it becomes possible to determine that the amount of stored liquid RL is generally equal to or greater than the lower limit even in cells 112 where the second liquid level sensor 50b is not installed. Furthermore, in the first cell 112a where the stored liquid RL decreases the slowest, in other words where the stored liquid RL remains the most and is most likely to overflow, by positioning the liquid level detection unit 51a of the first liquid level sensor 50a at a position where it can detect the second threshold value T2 as an upper limit value for preventing overflow of the first cell 112a, it becomes possible to know that overflow is imminent when the liquid level height becomes equal to or greater than the second threshold value T2.

[0078] Furthermore, a liquid measuring unit is provided between the first on-off valve 30 and the branched portion of the supply path 20. The liquid measuring unit has the function of measuring the pressure and flow rate of the liquid FL. As an example, the liquid measuring unit in this embodiment is composed of a pressure gauge 31 and a flow meter 32. Specifically, the pressure gauge 31 and the flow meter 32 are provided between the first on-off valve 30 and the branched portion of the supply path 20, respectively. The pressure gauge 31 transmits the pressure of the liquid FL flowing through the supply path 20 to the control unit 60. The flow meter 32 transmits the flow rate of the liquid FL flowing through the supply path 20 to the control unit 60.

[0079] In the present embodiment, the pressure gauge 31 and the flow meter 32 are respectively provided between the first on-off valve 30 and the branch portion of the supply path 20, but the present disclosure is not limited to this configuration. The flow meter 32 may be provided upstream of the first on-off valve 30 in the supply path 20 in the liquid supply direction. Furthermore, the pressure gauge 31 may also be provided upstream of the first on-off valve 30 in the liquid supply direction. Furthermore, one of the pressure gauge 31 and the flow meter 32 may be provided upstream of the first on-off valve 30 in the liquid supply direction, and the other of the pressure gauge 31 and the flow meter 32 may be provided downstream of the first on-off valve 30 in the liquid supply direction. In the present embodiment, since the liquid FL is supplied from the storage portion 14, the flow rate of the liquid flowing out of the storage portion 14 may be calculated based on, for example, a change in mass (a decrease in mass) or a change in liquid level (a decrease in liquid level) in the storage portion 14. In this case, the flow meter 32 may be omitted.

[0080] As shown in FIG. 2 , the control unit 60 includes, for example, a CPU (Central Processing Unit: processor) 61, a ROM (Read Only Memory) 62, a RAM (Random Access Memory) 63, and a storage 64.

[0081] The CPU 61 is a central processing unit that executes various programs and controls various parts. That is, the CPU 61 reads programs from the ROM 62 or the storage 64, and executes the programs using the RAM 63 as a work area. The CPU 61 controls the first on-off valve 30 and performs various arithmetic processing in accordance with the programs recorded in the ROM 62 or the storage 64. Note that, if a liquid supply pump is used to supply the liquid FL from the reservoir 14, for example, the CPU 61 controls the liquid supply pump in the same way as the first on-off valve 30.

[0082] The ROM 62 stores various programs and various data. The RAM 63 temporarily stores programs or data as a working area. The storage 64 is configured with an HDD (Hard Disk Drive) or an SSD (Solid State Drive) and stores various programs including the operating system and various data.

[0083] The control unit 60 has a function of controlling the driving (opening / closing operation) of the first on-off valve 30. Furthermore, as an example, the control unit 60 of this embodiment calculates the amount of liquid FL to be supplied (also referred to as the replenishment amount) to the battery 110 based on the charge / discharge history of the battery 110, and keeps the first on-off valve 30 open until the calculated supply amount is supplied to the battery 110. Specifically, the charge / discharge history of the battery 110 is stored in the storage 64. When supplying liquid FL to the battery 110, the control unit 60 reads the charge / discharge history of the battery 110 from the storage 64 and calculates the amount of liquid loss from the read charge / discharge history. The control unit 60 then sets the calculated amount of liquid loss as the amount of liquid FL to be supplied, and controls the first on-off valve 30 to remain open until the calculated amount of liquid FL is supplied to the battery 110. Note that because the amount of remaining liquid before liquid supply differs for each cell 112, when the liquid FL is supplied to each cell 112 via each branch path 22, the liquid level of the stored liquid RL may become equal to or greater than the first threshold value T1 before the entire supply amount calculated above is supplied. In this case, the second on-off valve 40 installed in the cell 112 where the liquid level of the stored liquid RL has become equal to or greater than the first threshold value T1 changes from an open state to a closed state, and the supply of the liquid FL to the target cell 112 is stopped. Then, the liquid FL continues to be supplied to the other cells 112 except for the cell 112 where the second on-off valve 40 has become closed.

[0084] In this embodiment, as an example, the liquid FL is purified water and the reservoir liquid RL is battery fluid. When the battery fluid is reduced in volume, the water (purified water component) in the battery fluid evaporates. Therefore, the battery fluid is replenished by supplying purified water, which is the liquid FL, to the battery fluid.

[0085] Furthermore, as an example, the control unit 60 of this embodiment changes the first on-off valve 30 from an open state to a closed state when the liquid level height detected by the liquid level sensor 50 in any of the cells 112 is equal to or greater than a second threshold value T2 that is greater than the first threshold value T1. Specifically, when the liquid level detection unit 51a of the first liquid level sensor 50a detects the liquid level LS of the stored liquid RL stored in the first cell 112a and receives the detection signal, the control unit 60 controls the driving of the first on-off valve 30 so that the first on-off valve 30 changes from an open state to a closed state in order to prevent liquid from overflowing from the first cell 112a.

[0086] Furthermore, as an example, the control unit 60 of this embodiment maintains the open state of the first on-off valve 30 when the liquid level height detected by the liquid level sensor 50 in any of the cells 112 is less than a third threshold value T3 that is smaller than the first threshold value T1. Specifically, the liquid level detection unit 51b of the second liquid level sensor 50b detects the liquid level LS of the stored liquid RL stored in the second cell 112b, and until the control unit 60 receives the detection signal, the control unit 60 controls the operation of the first on-off valve 30 so that the first on-off valve 30 can maintain the open state in order to prevent the second cell 112b from running dry.

[0087] Furthermore, the system 10 of this embodiment has, as an example, a function of charging the battery 110. Specifically, the system 10 further includes a charging cable 70 that connects the charger 16 and the battery 110. The battery 110 is charged via this charging cable 70.

[0088] Furthermore, the control unit 60 of this embodiment has, as an example, a function of controlling the start and stop of charging of the battery 110. The control unit 60 may also control the charging of the battery 110 and the supply of the liquid FL to be performed simultaneously, or may control the supply of the liquid FL to the battery 110 after or before charging. From the viewpoint of maintainability of the battery 110, it is preferable to perform the charging of the battery 110 and the supply of the liquid FL simultaneously. Here, performing the charging of the battery 110 and the supply of the liquid FL simultaneously means that the charging time and the liquid supply time overlap partially or entirely.

[0089] The supply of liquid FL from the storage section 14 to the battery 110 may be achieved by positioning the storage section 14 at a higher position than the battery 110, or by providing an electric liquid supply pump (not shown) to supply liquid FL from the storage section 14 to the battery 110 and controlling this liquid supply pump with the control section 60.

[0090] In this embodiment, the supply path 20, the first on-off valve 30, and the second on-off valve 40 constitute a replenishment device 12. The replenishment device 12 may include a storage unit 14. The replenishment device 12 may also include a control unit 60. The replenishment device 12 may also include a charger 16 and a charging cable 70.

[0091] Next, the flow of supplying liquid to the battery 110 using the system 10 of this embodiment will be described with reference to FIG.

[0092] First, in step S200, the control unit 60 determines (calculates) the amount of liquid FL to be supplied to the battery 110 based on the charge / discharge history of the battery 110. Specifically, the control unit 60 calculates the amount of liquid loss in the battery 110 based on the charge / discharge history of the battery 110, and sets this amount of liquid loss as the amount of liquid FL to be supplied.

[0093] Next, in step S202, the first on-off valve 30 is opened to supply the liquid FL to the battery 110 based on the calculated supply amount of the liquid FL. When the first on-off valve 30 is opened, the supply of the liquid FL begins.

[0094] Next, in step S204, the control unit 60 determines whether the pressure (fluid pressure) of the liquid FL in the supply path 20 is equal to or greater than a predetermined pressure or less than a predetermined pressure. Specifically, the control unit 60 monitors measurement data (hereinafter referred to as "pressure data") received from the pressure gauge 31, and determines whether the pressure of the liquid FL is equal to or greater than a predetermined pressure or less than a predetermined pressure based on this pressure data. If the determination result shows that the fluid pressure in the supply path 20 is equal to or greater than the predetermined pressure, the process proceeds to step S206, and if the fluid pressure in the supply path 20 is less than the predetermined pressure, the process proceeds to step S218.

[0095] Here, for example, when one second on-off valve 40 changes from an open state to a closed state, the hydraulic pressure in the supply path 20 decreases by a predetermined value. In other words, it is possible to determine whether a second on-off valve 40 is in a closed state based on a change in hydraulic pressure in the supply path 20 (here, a decrease in hydraulic pressure). For example, by setting the pressure value that decreases when three second on-off valves 40 become closed to the above-mentioned predetermined pressure, it is possible to determine whether the three second on-off valves 40 have changed from an open state to a closed state when the hydraulic pressure in the supply path 20 falls below the predetermined pressure. Step S218 will be described in detail later; this step S218 is a step in which the first on-off valve 30 is changed from an open state to a closed state. In other words, step S204 is a determination step for terminating the liquid supply in order to prevent excessive supply of the liquid FL when multiple second on-off valves 40 become closed before the supply amount calculated by the control unit 60 is completely supplied.

[0096] Next, in step S206, the control unit 60 determines whether the liquid level is less than the second threshold value T2 or greater than or equal to the second threshold value T2. Specifically, the control unit 60 monitors the detection data received from the first liquid level sensor 50a and determines, based on the detection data, whether the liquid level in the first cell 112a in which the first liquid level sensor 50a is installed is less than the second threshold value T2 or greater than or equal to the second threshold value T2. If the determination result shows that the liquid level is less than the second threshold value T2, the process proceeds to step S208. If the liquid level is greater than or equal to the second threshold value T2, the process proceeds to step S218. That is, step S206 is a determination step for terminating the liquid supply in order to prevent overflow due to excessive supply of the liquid FL when the liquid level in the first cell 112a in which the first liquid level sensor 50a is installed reaches or exceeds the second threshold value T2, which is the upper limit for overflow, before the supply amount calculated by the control unit 60 is completed.

[0097] Next, in step S208, the control unit 60 determines whether the calculated supply amount has been satisfied. Specifically, the control unit 60 monitors measurement data (hereinafter referred to as "flow rate data") received from the flow meter 32, and determines whether the amount of supplied liquid FL has satisfied the calculated supply amount based on this flow rate data. If the result of the determination is that the amount of supplied liquid FL satisfies the calculated supply amount, the process proceeds to step S218, but if the amount of supplied liquid FL does not satisfy the calculated supply amount, the process returns to (proceeds to) step S204.

[0098] Next, in step S210, the control unit 60 determines whether the liquid level is equal to or greater than the third threshold value T3 or less than the third threshold value T3. Specifically, the control unit 60 monitors the detection data received from the second liquid level sensor 50b and determines, based on the detection data, whether the liquid level in the second cell 112b in which the second liquid level sensor 50b is installed is equal to or greater than the third threshold value T3 or less than the third threshold value T3. If the determination result shows that the liquid level is equal to or greater than the third threshold value T3, the process proceeds to step S218. If the liquid level is less than the third threshold value T3, the process proceeds to step S212. That is, step S206 is a determination step for determining whether to continue liquid supply in order to prevent each cell 112 from running out of liquid after the supply amount calculated by the control unit 60 has been completed, in order to prevent each cell 112 from running out of liquid.

[0099] Next, in step S212, the control unit 60 maintains the open state of the first on-off valve 30. This allows the liquid supply to each cell 112 to continue.

[0100] Next, in step S214, similar to step S204, the control unit 60 determines whether the fluid pressure in the supply path 20 is equal to or greater than a predetermined pressure or less than a predetermined pressure. If the result of the determination is that the fluid pressure in the supply path 20 is equal to or greater than the predetermined pressure, the process proceeds to step S216, and if the fluid pressure in the supply path 20 is less than the predetermined pressure, the process proceeds to step S218. Step S214 is a determination step for terminating the continued liquid supply from the perspective of preventing excessive supply of the liquid FL when, for example, the plurality of second on-off valves 40 have become closed in a case where the supply of the liquid is continued after the supply of the supply amount calculated by the control unit 60 has been completed.

[0101] Next, in step S216, similar to step S206, the control unit 60 determines whether the liquid level height is less than the second threshold value T2 or equal to or greater than the second threshold value T2. If the result of the determination is that the liquid level height is less than the second threshold value T2, the process returns to (transitions to) step S212, whereas if the liquid level height is equal to or greater than the second threshold value T2, the process transitions to step S218. Step S206 is a determination step for terminating the liquid supply from the perspective of preventing liquid overflow due to excessive supply of liquid FL when the liquid level height in the first cell 112a in which the first liquid level sensor 50a is installed reaches or exceeds the second threshold value T2, which is the upper limit for liquid overflow, while liquid supply is continuing after the supply amount calculated by the control unit 60 has been completed.

[0102] In step S218, the control unit 60 changes the first on-off valve 30 from an open state to a closed state. Specifically, the control unit 60 controls the first on-off valve 30 to change from an open state to a closed state. When the first on-off valve 30 changes to the closed state, the liquid supply ends.

[0103] As described above, when the system 10 of this embodiment is used to supply the liquid to the battery 110, the maintainability of the battery 110 is improved.

[0104] Next, a maintenance method for the battery 110 according to this embodiment will be described. In this embodiment, the above-described system 10 is used as an example.

[0105] In the maintenance method for the battery 110 of this embodiment, charging of the battery 110 and supply of liquid to the battery 110 (the liquid supply described above) are performed simultaneously. Specifically, as shown in Fig. 7 , the control unit 60 controls the time so that the charging time of the battery 110 overlaps with the liquid supply time to the battery 110. By performing charging of the battery 110 and supplying liquid to the battery 110 simultaneously, the time required for charging and supplying liquid to the battery 110 can be shortened compared to when charging and supplying liquid to the battery 110 are performed separately, and the maintainability of the battery 110 is improved.

[0106] Furthermore, in the maintenance method for the battery 110 of this embodiment, it is preferable to start and complete the supply of the liquid FL between the start and completion of charging the battery 110. In this way, if the supply of the liquid to the battery 110 is completed from start to completion while the battery 110 is being charged, the time required for charging and supplying the liquid to the battery 110 can be further reduced. This further improves the ease of maintenance of the battery 110.

[0107] Furthermore, in the maintenance method for the battery 110 of this embodiment, it is preferable to complete the supply of liquid from the start of charging the battery 110 until the voltage of the battery 110 reaches a predetermined voltage t. For example, if the predetermined voltage t is set to a voltage lower than the voltage at which gassing occurs, completing the supply of liquid before the voltage of the battery 110 reaches the predetermined voltage t can prevent the supply of liquid from being affected by the occurrence of gassing. Note that the predetermined voltage t is preferably set to, for example, 2.5 V, more preferably 2.4 V, and even more preferably 2.3 V.

[0108] The charging current may be constant current charging, and the current value may be 0.05 C to 0.5 C. Here, 1 C represents the current value when the battery goes from a fully charged state to a fully discharged state in one hour. If the current value is 0.5 C or less, the amount of heat generated by the storage battery can be reduced, ensuring a sufficient amount of charge. Furthermore, if the current value is 0.05 C or more, charging in a short time is possible. Furthermore, the charging current may be semi-constant voltage charging, and the inrush current value may be 0.05 C to 0.5 C. Semi-constant voltage charging limits the current value to match the battery voltage, which has the effect of suppressing heat generation from the battery when charging at a high current value.

[0109] As described above, when the system 10 of this embodiment is used to charge and supply the battery 110 with a liquid, the maintainability of the battery 110 is improved.

[0110] Next, the effects of this embodiment will be described. In the system 10 of this embodiment, by opening both the first on-off valve 30 and the second on-off valve 40, the liquid FL is supplied to the battery 110 through the supply path 20. In the system 10, even if a malfunction occurs in the second on-off valve 40 during supply of liquid to the battery 110, the supply of liquid to the battery 110 can be stopped by switching the first on-off valve 30, which is located upstream of the second on-off valve 40 in the liquid supply direction, from an open state to a closed state. This makes it possible to prevent excessive supply of liquid FL to the battery 110. By preventing excessive supply of liquid FL to the battery 110 in this way, an increase in the frequency of maintenance of the battery 110 due to liquid overflow is prevented, improving the maintainability of the battery 110.

[0111] In particular, in the system 10 of this embodiment, the supply path 20 branches into multiple branch paths 22, which causes differences in the amount of liquid FL supplied to each cell 112 depending on the distance of each branch path 22, but because the multiple branch paths 22 are each provided with a second on-off valve 40, if the supply of liquid to any of the cells 112 becomes excessive, the second on-off valve 40 corresponding to the excess cell 112 can be closed to stop the supply of liquid to the cell 112. In this way, in the system 10, it is possible to suppress excessive supply of liquid FL to each cell 112 that constitutes the battery 110, compared to when the second on-off valve 40 is provided upstream of the branch portion of the supply path 20 in the liquid supply direction.

[0112] Furthermore, in the system 10 of the present embodiment, the driving (opening and closing operation) of the first on-off valve 30 is controlled by the control unit 60. Therefore, in the system 10, the burden on the worker can be reduced compared to when the worker manually drives the first on-off valve 30.

[0113] Furthermore, in the system 10 of this embodiment, the control unit 60 determines the amount of liquid FL to be supplied to the battery 110 based on the charge / discharge history of the battery 110. Then, the control unit 60 keeps the first on-off valve 30 open until the determined supply amount of liquid FL is supplied to the battery 110. Therefore, in the system 10, it is possible to efficiently supply a shortage of liquid FL to the battery 110 compared to a case in which a constant amount of liquid FL is always supplied to the battery 110 regardless of the charge / discharge history of the battery 110.

[0114] Furthermore, in the system 10 of this embodiment, when supplying liquid to the battery 110, the second on-off valve 40 remains open until the liquid level of the stored liquid RL stored in at least one cell 112 reaches a first threshold value T1. When the liquid level reaches or exceeds the first threshold value T1, the second on-off valve 40 transitions from an open state to a closed state, thereby stopping the supply of liquid to the battery 110. Specifically, when supplying liquid to the battery 110, if the liquid level in each cell 112 is less than the first threshold value T1, the second on-off valve 40 corresponding to each cell 112 transitions from an open state to a closed state, thereby stopping the supply of liquid FL to each cell 112. In this regard, in the system 10, if the first threshold value T1 is set to a liquid level that can prevent excessive supply of liquid FL to the battery 110, it is possible to further suppress an increase in the frequency of maintenance due to liquid overflow.

[0115] 4, in the system 10 of this embodiment, when the height of the liquid level LS detected by the liquid level detection unit 51a of the first liquid level sensor 50a installed in the first cell 112a, where the stored liquid decreases slowly, is equal to or greater than a second threshold value T2 that is greater than the first threshold value T1, the control unit 60 switches the first on-off valve 30 from an open state to a closed state. Here, in the system 10, if the upper limit for preventing liquid overflow from the first cell 112a is set to the second threshold value T2, for example, even if a malfunction occurs in the second on-off valve 40, the control unit 60 switches the first on-off valve 30 to a closed state when the liquid level reaches or exceeds the second threshold value T2, thereby effectively preventing liquid overflow due to an excessive supply of liquid FL to the battery 110 (e.g., liquid overflow from the first cell 112a).

[0116] In the system 10 of this embodiment, a first liquid level sensor 50a is installed in the first cell 112a, and a second liquid level sensor 50b is installed in the second cell 112b. The second cell 112b, which has the fewest contact surfaces with the metal container 114, is more likely to become hot than the first cell 112a, which has the most contact surfaces with the container 114, because it is more difficult or unable to dissipate heat through the container 114. Therefore, the stored liquid RL decreases faster in the second cell 112b than in the first cell 112a. Therefore, by installing the second liquid level sensor 50b in the second cell 112b, which decreases the stored liquid RL faster, and the first liquid level sensor 50a in the first cell 112a, which decreases the stored liquid RL more slowly, it is possible to supply liquid according to the decrease in the stored liquid RL in the second cell 112b, and to stop the liquid supply according to the overflow of the stored liquid RL in the first cell 112a.

[0117] 5, in the system 10 of this embodiment, when the height of the liquid level LS detected by the second liquid level sensor 50b installed in the second cell 112b, in which the stored liquid RL decreases quickly, is less than a third threshold value T3 that is smaller than the first threshold value T1, the control unit 60 opens the first on-off valve 30. Here, in the system 10, if the lower limit for preventing the second cell 112b from running dry is set to the third threshold value T3, and the supply of the liquid FL is low and the liquid level does not reach the third threshold value T3, the control unit 60 keeps the first on-off valve 30 open, thereby preventing the second cell 112b from running dry.

[0118] Furthermore, in the system 10 of this embodiment, when the liquid level is equal to or higher than the first threshold value T1, the valve element 44, which moves in conjunction with the float 42, contacts the valve seat 45 and closes the internal flow path 48. In this way, compared to when an electrically driven valve element 44 is used as the second on-off valve 40, an increase in costs related to the control of the second on-off valve 40 can be suppressed.

[0119] Furthermore, in the system 10 of this embodiment, the control unit 60 controls the start and stop of charging of the battery 110 by the charger 16. Therefore, in the system 10, the burden on the worker can be reduced compared to when the worker performs charging work including starting and stopping charging of the battery 110 by himself.

[0120] Furthermore, in the system 10 of this embodiment, when the control unit 60 simultaneously charges the battery 110 and supplies the liquid to the battery 110, the time required to charge the battery 110 and supply the liquid can be reduced compared to, for example, when the charging and supply of the liquid to the battery 110 are performed separately.

[0121] Depending on conditions such as the state and type of the battery 110, it may be preferable to supply liquid to the battery 110 after or before charging the battery 110. Therefore, in the system 10 of this embodiment, when the control unit 60 supplies liquid to the battery 110 after or before charging the battery 110, supplying liquid to the battery 110 after or before charging the battery 110 depending on the conditions of the battery 110 makes it possible to extend the life of the battery 110.

[0122] In the refilling device 12 of this embodiment, by opening both the first on-off valve 30 and the second on-off valve 40, the liquid FL is supplied to the battery 110 through the supply path 20. Here, in the refilling device 12, even if a malfunction occurs in the second on-off valve 40 during supply of liquid to the battery 110, the supply of liquid to the battery 110 can be stopped by switching the first on-off valve 30, which is located upstream of the second on-off valve 40 in the liquid supply direction, from an open state to a closed state. This makes it possible to prevent excessive supply of liquid FL to the battery 110. By preventing excessive supply of liquid FL to the battery 110 in this way, an increase in the frequency of maintenance due to liquid overflow is suppressed, and the maintainability of the battery 110 is improved.

[0123] In addition, the refilling device 12 of this embodiment is equipped with a storage section 14 for storing liquid FL, and therefore, for example, by storing liquid FL that has undergone a specified process in the storage section 14, maintenance time can be shortened.

[0124] The control unit 60 of this embodiment may be mounted in the charger 16, attached to the battery 110, attached to the mobile body on which the battery 110 is mounted, or installed in a location separate from these. The control unit 60 may also have a function as a so-called battery management system.

[0125] Furthermore, the system 10 of the present embodiment may charge and supply the liquid to the battery 110 by, for example, a user performing an operation to execute a maintenance mode set in the control unit 60. Here, the maintenance mode may include a mode in which both charging and supplying the liquid to the battery 110 are performed, and a mode in which only one of these is performed. Furthermore, the control unit 60 of the system 10 may monitor, for example, when a predetermined time has elapsed since the previous maintenance, when the voltage of the battery 110 falls below a predetermined voltage, when the liquid level in the second cell 112b falls below a third threshold T3, and the like, and when any one or a combination of these conditions is met, the system 10 may automatically execute the maintenance mode or may notify the user that the conditions have been met (including by notification via the Internet, etc.).

[0126] (Other Embodiments) The system 10 of the above-described embodiment may further include a catalyst unit 80 that reduces gas generated by electrolysis of the stored liquid RL (for example, battery fluid) and returns it to the liquid FL (for example, purified water). For example, the catalyst unit 80 may be connected to the second on-off valve 40. Specifically, as shown in FIG. 8 , a housing 81 for the catalyst unit 80 is connected to the housing 46 of the second on-off valve 40. The housing 81 includes a catalyst 82, a catalyst container 83 that accommodates the catalyst 82, and a splash guard 84. The catalyst 82 reacts with hydrogen and oxygen to produce water. The catalyst 36 includes a transition metal or a transition metal oxide. The catalyst 36 may also include, for example, a noble metal such as Pd, Pt, or Ag, or a base metal such as Fe, Co, or Mn. In the system 10 including the catalyst unit 80, the gas generated by electrolysis of the stored liquid RL is reduced by the catalyst unit 80 and returned to the liquid FL. Therefore, in the system 10, the rate of decrease of the stored liquid RL can be slower than in a case where the catalyst unit 80 is not provided. Furthermore, because the catalyst unit 80 is connected to the second on-off valve 40, the structure of the cell 112 can be simplified compared to a case where the catalyst unit 80 is provided in a location separate from the second on-off valve 40 of the cell 112. Note that the present disclosure is not limited to the above configuration, and the catalyst unit 80 and the second on-off valve 40 may be separately attached to the ceiling of the cell 112. In this case, the second on-off valve 40 and the catalyst unit 80 can be separately removed, facilitating part replacement and maintenance. Note that, although FIG. 8 illustrates an example in which the second on-off valve 40 with the catalyst unit 80 is installed in the first cell 112a, the present disclosure is not limited to this.

[0127] Furthermore, as shown in FIG. 9 , the system 10 of the above-described embodiment may include a joint mechanism 90 between the branched portion of the supply path 20 and the first on-off valve 30. The joint mechanism 90 releasably connects the supply path 20. Specifically, the joint mechanism 90 includes a male member 96 and a female member 94. Connecting the male member 96 to the female member 94 mechanically connects the male member 96 and the female member 94. Because the joint mechanism 90 releasably connects the branched portion of the supply path 20 to the first on-off valve 30, fewer parts need to be connected and disconnected, making connection of the supply path 20 easier than when the joint mechanism 90 is provided downstream of the branched portion of the supply path 20 in the liquid supply direction. This reduces the burden on the operator. The charging cable 70 may also include a joint mechanism 72. The joint mechanism 72 includes a male member 74 and a female member 76. Connecting the male member 74 to the female member 76 electrically connects the male member 74 and the female member 76. Here, the battery 110 can be removed by disconnecting the joint mechanism 90 and the joint mechanism 72. By using the system 10 in this manner, the battery 110 can be replaced while water is supplied to and charged from a new battery 110.

[0128] In the system 10 of the above-described embodiment, the cells 112 of the battery 110 are arranged in a 4-row, 4-column matrix, as an example. However, the present disclosure is not limited to this. For example, as shown in FIG. 10 , the cells 112 of the battery 110 may be arranged in a 2-row, 6-column matrix. In this case, as in the above-described embodiment, the cell with the most contact surfaces with the housing 124 is referred to as the first cell 112a, and the cell with the fewest contact surfaces with the housing 124 is referred to as the second cell 112b. Installing a first liquid level sensor 50a in at least one of the first cells 112a and a second liquid level sensor 50b in at least one of the second cells 112b can achieve the same effects as the system 10 of the above-described embodiment. The matrix arrangement of the multiple cells 112 in n rows and m columns (n ​​and m are positive integers) can be set depending on the equipment to which the multiple cells 112 are applied. Furthermore, the multiple cells 112 do not have to be arranged in an orderly manner.

[0129] In the system 10 of the above-described embodiment, a first liquid level sensor 50a is installed in at least one of the first cells 112a, and a second liquid level sensor 50b is installed in at least one of the second cells 112b. In addition, as shown in FIG. 11 , a cell 112 having a number of contact surfaces with the container 114 between the first cell 112a and the second cell 112b may be referred to as a third cell 112c. As shown in FIG. 12 , a third liquid level sensor 50c may be installed in the third cell 112c. It is preferable that the third liquid level sensor 50c be set to a fourth threshold T4, which is an optimal liquid level for each cell 112 between the first threshold T1 and the third threshold T3, in other words, within the range of less than the first threshold T1 and more than the third threshold T3. The liquid level at the fourth threshold T4 may be the same as the first threshold T1. Furthermore, since the third cell 112c is a cell 112 having properties intermediate between those of the first cell 112a, which is prone to overflowing, and the second cell 112b, which is prone to running dry, if this third cell 112c is set to the fourth threshold value T4, which is the optimal liquid level height, and if liquid supply is continued even after the calculated liquid supply is completed, the control unit 60 will keep the first opening / closing valve 30 open until the liquid supply reaches the fourth threshold value T4, thereby preventing liquid overflow due to excessive supply of liquid to the battery 110 and allowing liquid to be supplied up to the optimal value.

[0130] Furthermore, in the system 10 of the above-described embodiment, a liquid level sensor is used in which the liquid level detection unit is immersed in the liquid to detect the liquid level LS, but the present disclosure is not limited to this configuration. For example, a non-contact liquid level sensor may be used to detect the up and down movement of the liquid level LS in detail. In this case, a non-contact liquid level sensor may be provided in all cells 112, or a liquid level sensor may be provided in at least one of the first cells 112a and at least one of the second cells 112b.

[0131] In the system 10 of the above-described embodiment, the cells 112 in which the first liquid level sensor 50a and the second liquid level sensor 50b are installed are specified, but the present disclosure is not limited to this configuration. For example, the first liquid level sensor 50a and the second liquid level sensor 50b may be installed in all of the cells 112. Furthermore, the third liquid level sensor 50c may be installed in all of the cells 112.

[0132] While the embodiments of the present disclosure have been described above with reference to the accompanying drawings, it is clear that a person of ordinary skill in the art to which the present disclosure pertains can conceive of various modifications and applications within the scope of the technical ideas set forth in the claims, and it is understood that these naturally fall within the technical scope of the present disclosure. For example, FIG. 13 is a diagram illustrating a forklift 200 equipped with a battery 110 as an example of a mobile object. As shown in FIG. 13, the forklift 200 is equipped with the battery 110. The forklift 200 is driven by power supplied from the battery. The battery 110 is configured with a plurality of cells 112. For example, a lead-acid battery for a forklift equipped in the forklift 200 affects the loss of electrolyte depending on the operating conditions of the forklift. A storage battery that is connected to a load and repeatedly charged and discharged is sometimes called a cycle storage battery. The cycle lead-acid battery may be a lead-acid battery that is repeatedly used at a depth of discharge (DOD) of 1% to 99% of its rated capacity. In a lead-acid battery used in a forklift, the electrolyte may decrease and the remaining capacity may become low after the forklift has been operated for a certain period of time. In such a case, the lead-acid battery can be removed from the forklift and recharged simultaneously using the battery maintenance system 10 of this embodiment, thereby enabling efficient operation of the forklift. The battery maintenance system 10 may be provided with a joint mechanism that allows easy attachment and detachment of the charging cable and the electrolyte supply line to the battery. The charging cable 70 may be provided with a joint mechanism 72, and the supply line for supplying electrolyte to the battery may be provided with a joint mechanism 90. The battery maintenance system 10 of this embodiment is particularly effective for cycle lead-acid batteries used in mobile objects such as a forklift 200.

[0133] REFERENCE SIGNS LIST 10 Battery maintenance system 12 Replenishing device 14 Storage section 16 Charger 20 Supply path 22 Branch path 30 First on-off valve 32 Supply amount measuring section 40 Second on-off valve 42 Float 43 Shaft member 44 Valve body 45 Valve seat 46 Housing 47 Guide hole 50 Liquid level sensor 50A First liquid level sensor 50B Second liquid level sensor 60 Control section 64 Storage 70 Charging cable 72 Joint mechanism 74 Male member 76 Female member 80 Circulation section 81 Housing 82 Catalyst 83 Catalyst container 84 Splash-proof plate 90 Joint mechanism 94 Female member 96 Male member 110 Battery 112 Cell 112a First cell 112b Second cell 114 Storage box 120 Battery 124 Storage box 200 Forklift RL Stored liquid FL Liquid LS Liquid level SD Liquid supply direction T1 First threshold T2 Second threshold T3 Third threshold T4 Fourth threshold

Claims

1. A battery maintenance system comprising a supply path for supplying a liquid to a battery, a first on-off valve provided on the supply path, and a second on-off valve provided downstream of the first on-off valve in the supply direction of the liquid on the supply path.

2. The battery maintenance system according to claim 1, wherein the first on-off valve is an electrically driven valve, and further comprises a control unit for controlling the driving of the first on-off valve.

3. The battery maintenance system according to claim 2, further comprising a charging cable connecting a charger and the battery, wherein the control unit controls the start and stop of charging the battery.

4. The battery maintenance system according to claim 3, wherein the control unit performs charging of the battery and supply of the liquid together.

5. The battery maintenance system according to claim 3, wherein the control unit supplies the liquid after or before charging the battery.

6. The battery maintenance system according to claim 2, wherein the control unit obtains the supply amount of the liquid to the battery based on the charge and discharge history of the battery, and keeps the first on-off valve open until the obtained supply amount is supplied to the battery.

7. The battery maintenance system according to claim 6, wherein the battery is composed of a plurality of cells, and the second on-off valve is in an open state when the height of the liquid level of the liquid stored in at least one of the cells is less than a first threshold value, and is in a closed state when the height is equal to or greater than the first threshold value.

8. The battery maintenance system according to claim 7, further comprising a liquid level sensor for detecting the liquid level of the stored liquid, wherein the control unit closes the first on-off valve when the height of the liquid level detected by the liquid level sensor is equal to or greater than a second threshold value greater than the first threshold value.

9. The battery maintenance system according to claim 7, further comprising a liquid level sensor for detecting the liquid level of the stored liquid, wherein the control unit maintains the open state of the first on-off valve when the height of the liquid level detected by the liquid level sensor is less than a third threshold value less than the first threshold value.

10. The control unit maintains the open state of the first on-off valve when the height of the liquid level detected by the liquid level sensor is equal to or less than a fourth threshold value set between the first threshold value and the third threshold value. The battery maintenance system according to claim 9.

11. The battery is composed of a plurality of cells. The supply path branches into a plurality of paths in the middle to supply the liquid to each of the cells. The first on-off valve is provided upstream of the branching portion of the supply path in the supply direction. The second on-off valve is provided in each of a plurality of branch paths that constitute a portion of the supply path on the downstream side of the branching portion in the supply direction. The battery maintenance system according to claim 6.

12. Each of the second on-off valves is in an open state when the height of the reserved liquid stored in each cell is less than the first threshold value, and is in a closed state when it is equal to or greater than the first threshold value. The battery maintenance system according to claim 11.

13. The battery maintenance system according to claim 12, further comprising a liquid level sensor for detecting the liquid level of the reserved liquid. The liquid level sensor is installed in two or more of the cells. The control unit closes the first on-off valve when the height of the liquid level detected by at least one of the liquid level sensors is equal to or greater than a second threshold value that is greater than the first threshold value.

14. The plurality of cells are stored in parallel in a metal storage box. The liquid level sensor is installed in a first cell having the largest number of contact surfaces with the storage box and a second cell having the smallest number of contact surfaces with the storage box among the plurality of cells, respectively. The battery maintenance system according to claim 13.

15. The control unit opens the first on-off valve when the height of the liquid level detected by the liquid level sensor installed in the second cell is less than a third threshold value that is less than the first threshold value, and closes the first on-off valve when the height of the liquid level detected by the liquid level sensor installed in the first cell is equal to or greater than a second threshold value that is greater than the first threshold value. The battery maintenance system according to claim 14.

16. The battery maintenance system according to claim 7 or claim 12, wherein the second on-off valve includes a float floating on the liquid, and a valve body that moves in conjunction with the float and closes the internal flow path by contacting a valve seat when the height of the liquid level is equal to or higher than a first threshold value.

17. The battery maintenance system according to claim 7 or claim 12, further comprising a catalyst unit that reduces the gas generated by electrolysis of the stored liquid and returns it to the liquid.

18. The battery maintenance system according to claim 17, wherein the catalyst unit is connected to the second on-off valve.

19. The battery maintenance system according to claim 11, wherein the supply path is releasably connected between the branch portion and the first on-off valve by a joint mechanism.

20. A battery maintenance method for performing charging of a battery and supply of a liquid together.

21. The battery maintenance method according to claim 20, wherein supply of the liquid is performed from the start of supply to the end of supply during the period from the start of charging of the battery to the completion of charging.

22. The battery maintenance method according to claim 21, wherein supply of the liquid is completed before the voltage of the battery reaches a predetermined voltage.

23. A replenishing device comprising a supply path for supplying a liquid to a battery, a first on-off valve provided on the supply path, and a second on-off valve provided downstream of the first on-off valve in the supply direction of the liquid on the supply path.

24. The replenishing device according to claim 23, wherein the first on-off valve is a valve driven electrically, and further comprises a control unit that controls driving of the first on-off valve.

25. The replenishing device according to claim 24, further comprising a charger and a charging cable connecting the charger and the battery, wherein the control unit controls start and stop of charging of the battery.

26. The replenishing device according to any one of claims 23 to 25, further comprising a storage unit provided upstream of the first on-off valve in the supply direction of the liquid in the supply path for storing the liquid.

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