Battery system

Abstract

To stabilize the output power of a battery system that uses multiple connected batteries. [Solution] The battery system comprises multiple batteries, switches positioned between each battery, and at least one of the following sensors: a voltage sensor for measuring the voltage of each battery and a current sensor for measuring the current of each battery. Furthermore, in this battery system, the connections between the batteries are switched based on the sensor readings.

Description

[Technical Field]

[0001] This specification discloses a technology relating to a battery system. [Background Art]

[0002] Patent Document 1 discloses a technology related to a fuel cell using microorganisms. In the fuel cell of Patent Document 1, electrons generated when microorganisms decompose organic matter are collected by an anode to generate power. Note that hydrogen generated when organic matter is decomposed (hereinafter referred to as protons) moves to the cathode. On the cathode surface, protons and electrons react with oxygen to generate water. Such a fuel cell can purify wastewater while generating power. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2019-110101 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In a fuel cell using microorganisms like that described in Patent Document 1, the power output by each individual fuel cell is low. Therefore, in order to use the fuel cell as a practically usable battery, it is necessary to connect and use a plurality of fuel cells. However, in a fuel cell using microorganisms, output power changes due to changes in the environment in which microorganisms live (the amount of water such as wastewater, and the amount of organic matter). In addition, the output power of each individual fuel cell often varies. Therefore, even when a plurality of fuel cells using microorganisms are connected, variations may occur in the output power. This phenomenon is a problem common to battery systems that use a plurality of connected batteries. Therefore, development of a battery system with stable output power is desired. The purpose of this specification is to provide a technology for stabilizing the output power of a battery system that uses a plurality of connected batteries. [Means for Solving the Problem]

[0005] The first technology disclosed herein is a battery system comprising a plurality of batteries, a switch positioned between each of the batteries, and at least one of a voltage sensor for measuring the voltage of each battery and a current sensor for measuring the current of each battery. In this battery system, the connections between each of the batteries may be switched based on the measured values ​​of the sensors.

[0006] A second technology disclosed herein is a battery system of the first technology, wherein each of the batteries may be connected using only the batteries whose measurement value from the sensor is equal to or greater than a predetermined value.

[0007] A third technology disclosed herein is a battery system of the first or second technology described above, which may include a second sensor for measuring at least one of the combined voltage and combined current of the connected batteries.

[0008] The fourth technology disclosed herein is a battery system of any of the first to third technologies described above, wherein a second switch may be provided on the wiring connected to the load.

[0009] The fifth technology disclosed herein is a battery system of any of the first to fourth technologies described above, wherein the battery may be a microbial fuel cell. [Effects of the Invention]

[0010] According to the first technology, even if the voltage (or current) values ​​of each battery are different, the output voltage (or current) can be kept constant (above a specified value) by switching a switch. Furthermore, by switching the switch, the output voltage (or current) can be temporarily changed (increased or decreased).

[0011] According to the second technology, it is possible to construct a circuit without using a battery with high resistance (low output).

[0012] According to the third technology, it is possible to measure the voltage value (combined voltage value) and / or the current value (combined current value) output from the circuit configured by connecting each battery. In other words, it is possible to measure not only the calculated voltage and / or current values ​​output from the circuit when each battery is connected, but also the actual voltage and / or current values ​​output to the load.

[0013] According to the fourth technology, it is possible to switch the battery connection not only while voltage (current) is being output to the load, but also while voltage (current) is not being output to the load. For example, before starting to output voltage (current) to the load, the battery connection is switched while voltage (current) is not being output to the load. Then, if it becomes necessary to switch the battery connection while voltage (current) is being output to the load, the battery connection can be switched while voltage (current) is still being output to the load.

[0014] According to the fifth technology, even with microbial fuel cells, which are prone to variations in battery output depending on the environment, it is possible to suppress deviations in the combined voltage (or combined current) from the specified value (rated voltage or rated current of the load). Furthermore, according to the fifth technology, it is also possible to purify wastewater, etc., while generating electricity. [Brief explanation of the drawing]

[0015] [Figure 1] A schematic diagram of the battery system of the first embodiment is shown. [Figure 2] An example of the operation of the battery system of the first embodiment is shown. [Figure 3] A diagram illustrating the batteries that make up a battery system is shown. [Figure 4] A diagram illustrating the configuration of each battery is shown. [Figure 5] A flowchart illustrating the operation of the battery system is shown. [Figure 6] A flowchart illustrating the operation of the battery system is shown. [Figure 7]Fig. 1 is a schematic diagram of the battery system according to the second embodiment. [Figure 8] An operation example of the battery system according to the second embodiment is shown. [Figure 9] Fig. 1 is a schematic diagram of the battery system according to the third embodiment. [Figure 10] An operation example of the battery system according to the third embodiment is shown. [Figure 11] Another operation example of the battery system according to the third embodiment is shown. MODE FOR CARRYING OUT THE INVENTION

[0016] (First Embodiment) The battery system 10 will be described with reference to Fig. 1. The battery system 10 includes six batteries B1 to B6 each provided with a voltage sensor, a voltage sensor V that measures a voltage between the battery B4 and the battery B6, and five switches 1 to 5 disposed between the batteries B1 to B6. The batteries B4, B5, B6 and the switches 4, 5 are connected in series. The switch 4 controls connection between the battery B4 and the battery B5. The switch 5 controls connection between the battery B5 and the battery B6. The battery B4 and the battery B6 are also connected in series to a load L and a switch 6. The switch 6 controls connection between the battery B4 and the battery B6, and connection to the load L. The voltage sensor V is an example of a second sensor, and the switch 6 is an example of a second switch.

[0017] The battery B1 is connected in series to the battery B2 and the battery B4. The switch 1 is disposed on a wiring between the battery B1 and the battery B4. The switch 1 can switch on / off of the connection between the battery B1 and the battery B4.

[0018] The battery B2 is connected in series to the battery B1, the battery B3 and the battery B4. The switch 2 is disposed on a wiring between the battery B2 and the battery B4. The switch 2 can switch on / off of the connection between the battery B2 and the battery B4.

[0019] Battery B3 is connected in series with batteries B2, B5, and B6. Switch 3 is located on the wiring between battery B3 and battery B6. Switch 3 can switch batteries B3 and B6 on and off.

[0020] Battery B4 is connected in series with batteries B1, B2, and B5. Switch 1 is located on the wiring between battery B4 and battery B1, switch 2 is located on the wiring between battery B4 and battery B2, and switch 4 is located on the wiring between battery B4 and battery B5. Switch 4 can switch batteries B4 and B5 on and off. Battery B4 is also connected in series with battery B6. A load L is connected on the wiring between battery B4 and battery B6. Switch 6 is located on the wiring between battery B4 and battery B6, and switch 6 switches the power supply to load L on and off.

[0021] Battery B5 is connected in series with batteries B3, B4, and B6. Switch 4 is located between batteries B5 and B4, and switch 5 is located on the wiring between batteries B5 and B6. Switch 5 can switch batteries B5 and B6 on and off.

[0022] Battery B6 is connected in series with batteries B3 and B5. Switch 3 is located on the wiring between battery B6 and battery B3, and switch 5 is located on the wiring between battery B6 and battery B5. Battery B6 is also connected in series with battery B4 via switch 6 and load L. In other words, switch 6 is located between battery B6 and load L. Battery B6 constitutes the output section of the battery system 10.

[0023] In the battery system 10, the combined voltage output to the load L can be changed by switching switches 1 to 5. Specifically, the battery system 10 can output a constant voltage (above a specified value) even if the voltages of batteries B1 to B6 are different. Alternatively, the battery system 10 can output a constant voltage even if the voltage of any of batteries B1 to B6 changes. The voltage sensor V and load L are connected in parallel between batteries B4 and B6. Therefore, the voltage sensor V can measure the combined voltage applied to the load L.

[0024] Referring to Figure 2, an example of the operation of the battery system 10 will be described. Figure 2 describes an example where it is necessary to apply a voltage of 2V or more to the load L (the rated voltage of the load L is 2V). When the voltages of batteries B1 to B6 are as follows, switch 1 and switch 3 are connected as shown in (a) to form a series circuit of battery B4-battery B1-battery B2-battery B3-battery B6. Battery B1: 0.3V Battery B2: 0.4V Battery B3: 0.5V Battery B4: 0.5V Battery B5: 0.5V Battery B6: 0.5V

[0025] By forming a series circuit of batteries B4-B1-B2-B3-B6, a combined voltage of (0.5+0.3+0.4+0.5+0.5=2.2)V can be applied to the load L. Furthermore, in the battery system 10, if, for example, battery B1 malfunctions and becomes unable to discharge (increased electrical resistance), switches 1 to 5 are switched as shown in (b). In (b), switches 2 and 5 are turned on, and in addition, switches 1 and 3 are turned off, forming a series circuit of batteries B4-B2-B3-B5-B6. As a result, a combined voltage of (0.5+0.4+0.5+0.5+0.5=2.4)V is applied to the load L. In this way, the battery system 10 can always apply a voltage of 2V or more to the load L by switching switches 1 to 5 and changing the connection of batteries B1 to B6.

[0026] Now, referring to Figure 3, batteries B1 to B6 will be described. Figure 3 shows a conceptual diagram of the battery pack 40. The battery pack 40 comprises a battery module 30 composed of multiple battery cells 20, and components 32 such as a cooling structure and a case. A battery cell 20 is sometimes called a single cell. Each of the batteries B1 to B6 that make up the battery system 10 may be a battery pack 40, a battery module 30, or a battery cell 20.

[0027] Furthermore, each of the batteries B1 to B6 may be, for example, a storage battery used in electric vehicles, stationary storage batteries, etc., or a power generation device such as a solar cell, wind power generation, geothermal power generation, or microbial fuel cell. The battery system 10 can use the storage batteries, power generation devices described above, or other storage batteries, power generation devices as batteries B1 to B6. In the battery system 10, a microbial fuel cell 50 is used as batteries B1 to B6. The structure of the microbial fuel cell 50 will be described below.

[0028] Figure 4 shows a schematic diagram of the microbial fuel cell 50. The microbial fuel cell 50 includes an anode electrode 54 placed in soil 52 containing moisture such as mud, a cathode electrode 56 placed on the surface of the soil 52, a voltage sensor V1 for measuring the voltage between electrodes 54 and 56, and a current sensor A1 for measuring the current between electrodes 54 and 56. Voltage sensors V2 and V3 have data loggers and record the potential of the anode electrode 54 and cathode electrode 56 of the microbial fuel cell 50 (potential relative to a reference electrode 58).

[0029] Within the soil 52, acetic acid produced by the decomposition of organic matter by microorganisms moves to the anode electrode 54. Oxidation of acetic acid takes place at the anode electrode 54. Then, electrons move from the anode electrode 54 to the cathode electrode 56. Also, protons produced by the decomposition of organic matter by microorganisms move to the cathode electrode 56. At the cathode electrode 56, electrons and protons react with oxygen (reduction) to produce water. In this way, the microbial fuel cell 50 can generate electricity. Furthermore, because ions (acetic acid ions, protons) move to the cathode electrode 56 and the anode electrode 54, the soil 52 is maintained in an electrically neutral state.

[0030] Furthermore, the microbial fuel cell 50 utilizes a reference electrode 58 made of a 0.3 mol / L KCl aqueous solution 60 to measure the potentials of the anode electrode 54 and the cathode electrode 56. Specifically, the reference electrode 58 and liquid junction 62 are placed in the KCl aqueous solution 60, a voltage sensor V2 is placed between the reference electrode 58 and the cathode electrode 56, and a voltage sensor V3 is placed between the reference electrode 58 and the anode electrode 54. The liquid junction 62 is also connected to the cathode electrode 56 and the anode electrode 54. This allows for the measurement of the potentials of the cathode electrode 56 and the anode electrode 54 (potential relative to the reference electrode 58). Voltage sensors V2 and V3 have data loggers that record changes in the potentials of the cathode electrode 56 and the anode electrode 54. The reference electrode 58 is a silver / silver chloride electrode, and the liquid junction 62 is formed from lead wires and platinum wires.

[0031] Next, referring to Figures 5 and 6, the switching method for switches 1 to 5 and switch 6 of the battery system 10 will be explained. Figure 2 will also be referred to as appropriate in the following explanation. First, with switch 6 turned off and unconnected to the load L, the voltages of each battery B1 to B6 are measured (step S2). Next, using batteries with a voltage equal to or greater than the specified value (e.g., 0.1V), the battery connection method is determined (step S4). In the case of battery system 10, switch 1 and switch 3 are connected to form a series circuit of battery B4-battery B1-battery B2-battery B3-battery B6 (see also Figure 2(a)).

[0032] Next, a determination is made (step S4) as to whether it is possible to output a combined voltage equal to or greater than the specified value (rated voltage of load L, 2V) using the determined connection method. If it is not possible to output a combined voltage equal to or greater than the specified value (step S6: NO), the process proceeds to step S26 to report an error. Examples of cases where it is not possible to output a combined voltage equal to or greater than the specified value include: battery B1: 0.2V, battery B2: 0.4V, battery B3: 0.2V, battery B4: 0.3V, battery B5: 0.3V, battery B6: 0.4V, etc. In this case, no matter how batteries B1 to B6 are connected, it is not possible to output a combined voltage equal to or greater than the specified value.

[0033] If the determined connection method can output a combined voltage equal to or greater than the specified value (Step S6: YES), switch 1 and switch 3 are turned on, and switches 2, 4, and 5 are turned off (Step S8). Next, the combined voltage of the connected circuit (battery B4 - battery B1 - battery B2 - battery B3 - battery B6) is measured (Step S10). The combined voltage is measured using the voltage sensor V (see also Figure 2). Next, it is determined whether the combined voltage measured by the voltage sensor V is equal to or greater than the specified value (Step S12). If the combined voltage is less than the specified value (Step S12: NO), return to Step S4 and reconsider the connection method of switches 1 to 5.

[0034] If the combined voltage is above the specified value (Step S12: YES), switch 6 is turned on and the circuit is connected to the load L (Step S14). As described above, in the battery system 10, the voltage of the circuit (battery B4-battery B1-battery B2-battery B3-battery B6) is 2.2V (Step S12: YES), so switch 6 is turned on and the circuit is connected to the load L (see also Figure 2(a)). Then, with switch 6 connected to the load L, the combined voltage of the circuit is measured (Step S16). Next, the voltage sensor V measures whether or not the combined voltage of the circuit is above the specified value (2V) (Step S18). The measurement in this step differs from that in Step S12 in whether or not the circuit is connected to the load L.

[0035] If the combined voltage of the circuit is equal to or greater than the specified value (2V) (Step S18: YES), the process proceeds to Step S20 to determine whether or not to terminate the power supply to the load L. If the power supply to the load L is to be terminated (Step S20: YES), switch 6 is turned off (Step S24), and the power supply to the load L is terminated. On the other hand, if the power supply to the load L is to be continued (Step S20: NO), the process returns to Step S18 to measure whether or not the combined voltage of the circuit is equal to or greater than the specified value (2V). In other words, the combined voltage of the circuit is continuously measured while the load L is powered.

[0036] If, in step S18, it is determined that the combined voltage of the circuit is less than the specified value (2V) (step S18: YES), the process proceeds to step S30. In step S18, the combined voltage of the circuit may fall below the specified value (2V). For example, when the circuit is connected to the load L in step S14, the combined voltage of the circuit may decrease due to a voltage drop. Alternatively, while the load L is energized, the voltages of batteries B1 to B6 may decrease, causing the combined voltage of the circuit to decrease.

[0037] When the process proceeds to step S30, steps S32, S34, S36, S38, and S40 are executed. The contents of steps S32, S34, S36, S38, and S40 are the same as those of S2, S4, S6, S8, and S10, respectively. The difference between steps S32-S40 and steps S2-S10 is that steps S32-S40 determine the connection method of switches 1-5 and switch switches 1-5 with the circuit connected to load L, whereas steps S2-S10 determine the connection method of switches 1-5 and switch switches 1-5 without the circuit connected to load L.

[0038] If, regardless of how batteries B1 to B6 are connected, it is not possible to output a combined voltage equal to or greater than the specified value (2V) (step S36: NO), the process proceeds to step S26 to report an error. After measuring the combined voltage of the newly connected circuit (for example, battery B4-battery B2-battery B3-battery B5-battery B6 in Figure 2(b)) (step S40), the process proceeds to step S18.

[0039] The advantages of battery system 10 are explained below. In battery system 10, the connection method of batteries B1 to B6 can be changed by switching switches 1 to 5. Therefore, even if the voltages of each battery B1 to B6 are different, a constant voltage can be output by switching switches 1 to 5. Also, even if loads L with different specified values ​​(rated voltages) are connected to battery system 10, the required voltage can be output by switching switches 1 to 5. Alternatively, if it becomes necessary to apply a different voltage to load L temporarily, the output voltage can be changed by switching switches 1 to 5. Furthermore, by switching switches 1 to 5, it is possible to configure the circuit while avoiding batteries with high resistance (low voltage).

[0040] Furthermore, because it has a voltage sensor V, it can measure the actual voltage applied to the load L from the circuit, rather than the combined voltage calculated from the voltages of each battery B1 to B6. Also, because it has a voltage sensor V, it can measure the output power of the circuit while voltage is applied to the load L. Therefore, even if the output voltage changes while the load L is energized (for example, if the output voltage drops), it is possible to switch switches 1 to 5 again and apply a voltage above the specified value to the load L.

[0041] A switch 6 is provided on the wiring connecting battery B6 and load L. By providing switch 6, switches 1 to 5 can be switched even when no voltage is applied to load L, and also when voltage is applied to load L. By switching switches 1 to 5 when no voltage is applied to load L, a voltage higher than the specified value can be applied to load L.

[0042] Furthermore, by switching switches 1 to 5 while voltage is applied to load L, it is possible to apply a voltage above the specified value to load L even if a voltage drop occurs due to current generation when the circuit is connected to load L. Also, even if the output voltage of the circuit changes while power is being applied to load L, the output voltage can be maintained above the specified value. In other words, even if the voltage of any of batteries B1 to B6 changes, the combined voltage applied to load L can be kept constant. Alternatively, the voltage applied to load L can be temporarily changed.

[0043] In the battery system 10, each battery B1 to B6 is composed of a microbial fuel cell 50. The output voltage of the microbial fuel cell 50 is prone to fluctuations depending on the environment in which it is placed (soil moisture, type of microorganism, and amount of microorganisms). Therefore, simply connecting batteries B1 to B6 may not be sufficient to obtain the required combined voltage. Since the battery system 10 allows switching the connection of each battery B1 to B6, it is possible to obtain the required (above specified) combined voltage even if each battery B1 to B6 is composed of a microbial fuel cell 50.

[0044] (Second example) The battery system 110 will be described with reference to Figures 7 and 8. Note that the battery system 110 is a modified version of the battery system 10. Therefore, in the battery system 110, components that are substantially the same as those in the battery system 10 may be omitted from the description by assigning them the same reference number as the battery system 10, or one with the same last two digits.

[0045] In the battery system 110, battery B1 is connected in series with batteries B2 and B4. Switch 101 is located on the wiring between batteries B1 and B4. Switch 101 can switch batteries B1 and B4 on and off. Battery B2 is connected in series with batteries B1 and B3.

[0046] Battery B3 is connected in series with batteries B2, B5, and B6. Switch 103 is located on the wiring between battery B3 and battery B6. Switch 103 can switch batteries B3 and B6 on and off.

[0047] Battery B4 is connected in series with batteries B1 and B5. Switch 101 is located on the wiring between battery B4 and battery B1, and switch 104 is located on the wiring between battery B4 and battery B5. Switch 104 can switch batteries B4 and B5 on and off. Battery B4 is also connected in series with battery B6. A load L is connected on the wiring between battery B4 and battery B6. Switch 106 is located on the wiring between battery B4 and battery B6. Switch 106 switches the connection between battery B4 and battery B6 on and off, and the power supply to load L on and off.

[0048] Battery B5 is connected in series with batteries B3, B4, and B6. Switch 104 is located between batteries B5 and B4, and switch 105 is located on the wiring between batteries B5 and B6. Switch 105 can switch batteries B5 and B6 on and off. Battery B5 is also connected to the wiring between battery B4 and load L via switch 102. By switching switch 102 on and off, it is possible to switch between a circuit where load L is connected between batteries B4 and B6 and a circuit where load L is connected between batteries B5 and B6.

[0049] Battery B6 is connected in series with batteries B3 and B5. Switch 103 is located on the wiring between battery B6 and battery B3, and switch 105 is located on the wiring between battery B6 and battery B5. Additionally, switch 106 is located between battery B6 and load L. Battery B6 is connected in series with battery B4 or battery B5 via switch 106 and load L.

[0050] Referring to Figure 8, an example of the operation of the battery system 110 will be described. Note that the battery system 110 has the same functions and effects as the battery system 10. The battery system 110 is particularly useful when temporarily changing (increasing) the voltage applied to the load L. Figure 8 describes an example in which the voltage applied to the load L is temporarily increased from 1.0V to 2.2V.

[0051] First, as shown in (a), switches 101, 102, and 105 are turned on to form a series circuit of battery B5 and battery B6. By forming a series circuit of battery B5 and battery B6, a combined voltage of (0.5 + 0.5 = 1.0) V can be applied to the load L. Next, as shown in (b), switches 102 and 105 are turned off, and switch 103 is turned on to form a series circuit of battery B4, battery B1, battery B2, battery B3, and battery B6. By forming a series circuit of battery B4, battery B1, battery B2, battery B3, and battery B6, a combined voltage of (0.5 + 0.3 + 0.4 + 0.5 + 0.5 = 2.2) V can be applied to the load L.

[0052] The battery system 110 connects battery B5 to the wiring connecting battery B4 and load L via switch 102. Therefore, it is possible to switch between a circuit in which load L is connected between batteries B4 and B6 and a circuit in which load L is connected between batteries B5 and B6, thereby significantly changing the combined voltage applied to load L. Note that the switching method of switches 101-105 and switch 106 of the battery system 110 is substantially the same as that of the battery system 10 (see also Figures 5 and 6).

[0053] (Third embodiment) The battery system 210 will be described with reference to Figures 9 to 11. Note that the battery system 210 is a modified version of the battery systems 10 and 110. Therefore, in the battery system 210, for components that are substantially the same as those in the battery systems 10 and 110, the description may be omitted by assigning them the same reference number as those assigned to the battery systems 10 and 110, or one with the same last two digits.

[0054] In the battery system 210, battery B1 is connected in series with batteries B2 and B4. Switch 201 is located on the wiring between batteries B1 and B2. Switch 201 can switch batteries B1 and B2 on and off.

[0055] Battery B2 is connected in series with batteries B1 and B3. Switch 201 is located on the wiring between batteries B2 and B1, and switch 202 is located on the wiring between batteries B2 and B3. Switch 202 can switch batteries B2 and B3 on and off. Also, battery B3 is connected in series with batteries B2 and B6. Switch 202 is located on the wiring between batteries B3 and B2.

[0056] Battery B4 is connected in series with batteries B1 and B5. Switch 203 is located on the wiring between batteries B4 and B5. Switch 203 can switch batteries B4 and B5 on and off.

[0057] Battery B5 is connected in series with batteries B4 and B6. Switch 203 is located on the wiring between batteries B5 and B4, and switch 204 is located on the wiring between batteries B5 and B6. Switch 204 can switch batteries B5 and B6 on and off. Also, battery B6 is connected in series with batteries B3 and B5. Switch 204 is located on the wiring between batteries B6 and B5.

[0058] In the battery system 210, the load L, current sensor A, and voltage sensor V are connected in parallel to the wiring between batteries B1 and B4, and to the wiring between batteries B3 and B6. That is, in the battery system 210, the series circuits of batteries B1, B2, and B3 are connected in parallel to the series circuits of batteries B4, B5, and B6. A switch 206 is located on the wiring connecting the wiring between batteries B3 and B6 to the load L. The switch 206 switches the connection between batteries B4 and B6 on / off, and the power supply to the load L on / off.

[0059] In the battery system 210, switches 201 to 204 are switched based on the combined current value supplied to the load L. Current sensor A and load L are connected in series. In addition, current sensor A, load L, and voltage sensor V are connected in parallel to the circuit consisting of batteries B1 to B6. Therefore, current sensor A can measure the current value flowing through load L when current is flowing through load L (when switch 206 is ON). That is, when switch 206 is OFF, it is not possible to measure the combined current value output from the circuit consisting of batteries B1 to B6.

[0060] On the other hand, the voltage sensor V can measure the combined voltage (open-circuit voltage) of the circuit composed of batteries B1 to B6 even when no current is flowing through the load L.

[0061] Referring to Figures 10 and 11, an example of the operation of the battery system 210 will be described. Note that the battery system 210 has the same functions and effects as the battery systems 10 and 110. That is, like the battery systems 10 and 110, the battery system 210 can maintain a constant combined current supplied to the load L. Furthermore, it can temporarily change the combined current value supplied to the load L.

[0062] Figure 10 shows an example of maintaining a constant current value supplied to the load L. (a) shows an example in which a combined current is supplied to the load L from the series circuit of batteries B1, B2, and B3. Specifically, switches 201, 202, and 204 are turned on, and switch 203 is turned off. As a result, no current is supplied to the load L from the series circuit of batteries B4, B5, and B6, and current is supplied to the load L only from the series circuit of batteries B1, B2, and B3. Alternatively, switch 204 may be turned off instead of switch 203. Or, both switches 203 and 204 may be turned off.

[0063] (b) shows the case where a malfunction occurs in battery B1, making it unable to discharge (increased electrical resistance). When a malfunction occurs in battery B1, switch 201 is turned off and switch 203 is turned on. As a result, no current is supplied to load L from the series circuit of batteries B1, B2, and B3, and current is supplied to load L from the series circuit of batteries B4, B5, and B6. In this way, the current value supplied to load L can be kept constant.

[0064] Figure 11 shows an example of temporarily changing (increasing) the current supplied to load L. In (a), current is supplied to load L only from the series circuit of batteries B1, B2, and B3. To temporarily increase the current supplied to load L, switch 203 is turned on as shown in (b). As a result, the combined current of the current flowing through the series circuit of batteries B1, B2, and B3 and the current flowing through the series circuit of batteries B4, B5, and B6 is supplied to load L. In this way, the current supplied to load L can be temporarily increased. Note that the switching method of switches 201 to 204 and switch 206 of battery system 210 is substantially the same as that of battery system 10, and can be implemented by replacing "voltage" with "current" as shown in Figures 5 and 6.

[0065] (Other embodiments) In the above embodiment, a battery system using six batteries was described. However, the number of batteries constituting the battery system may be five or fewer, or seven or more. Furthermore, the switches placed between each battery are not limited to the configuration of the above embodiment and may be placed between any batteries. The important aspect of the technology disclosed herein is to change the connection configuration of multiple batteries using switches and adjust the voltage (current) output to the load to a desired voltage (current) value.

[0066] Furthermore, the voltage sensor V and / or current sensor A are not essential components and may be omitted. Even if the voltage sensor V and / or current sensor A are omitted, the combined voltage and / or combined current can still be calculated from the voltage and / or current values ​​of each battery.

[0067] Additionally, the switches (switches 6, 106, and 206) located on the wiring connected to load L may be removed. Power supply to load L can also be stopped by turning off the switches (switches 1-5, 101-105, and 201-204) located between each battery.

[0068] Furthermore, in the microbial fuel cell 50, the reference electrode 58, liquid junction 62, voltage sensor V2, and voltage sensor V3 may be omitted. The voltage and current between the cathode electrode 56 and the anode electrode 54 can be measured by the voltage sensor V1 and current sensor A1 without measuring the potential between the cathode electrode 56 and the anode electrode 54.

[0069] Although embodiments of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. Furthermore, the technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of symbols]

[0070] 1, 2, 3, 4, 5: Switch 6: The second switch 10: Battery System 50: Microbial fuel cell A: Second sensor A1: Current sensor B1~B6:Battery V: Second sensor V1: Voltage sensor

Claims

1. A battery system comprising multiple batteries, Multiple batteries, A switch is positioned between each of the aforementioned batteries, The system includes at least one of the following sensors: a voltage sensor for measuring the voltage of each battery and a current sensor for measuring the current of each battery. A battery system in which the connections between each of the batteries are switched based on the measured values ​​of the sensor.

2. The battery system according to claim 1, Each of the aforementioned batteries is connected to a battery system that uses only the batteries whose measurement value from the sensor is equal to or greater than a predetermined value.

3. The battery system according to claim 1, A battery system comprising a second sensor for measuring at least one of the combined voltage and combined current of the connected batteries.

4. The battery system according to claim 1, A battery system in which a second switch is provided on the wiring connected to the load.

5. A battery system according to any one of claims 1 to 4, The aforementioned battery is a battery system that is a microbial fuel cell.

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