Battery pack

Abstract

To obtain a battery pack capable of enhancing safety.SOLUTION: A battery pack according to one embodiment of the present disclosure comprises: a storage battery that has a positive electrode and a negative electrode and is capable of storing power; a thermoelectric conversion element that is thermally connected to the storage battery and is capable of generating power via thermoelectric conversion; and a first switch that is provided in a passage connecting the positive electrode and the negative electrode, that has a control terminal to which power generated by the thermoelectric conversion element is applied, and that becomes an on-state based on the power generated by the thermoelectric conversion element to allow the storage battery to be discharged.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack including a storage battery. [Background technology]

[0002] In battery packs equipped with storage batteries, temperature is often detected and controlled. For example, Patent Document 1 discloses a technology for equalizing the temperature of multiple battery cells using a Peltier element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-23527 Summary of the Invention [Problem to be solved by the invention]

[0004] However, battery packs are desired to be highly safe, for example, when the battery pack is placed near a heat source or when the storage battery of the battery pack generates heat, and further improvements in safety are expected.

[0005] It is desirable to provide a battery pack that can enhance safety. [Means for solving the problem]

[0006] A battery pack according to an embodiment of the present disclosure includes a storage battery, a thermoelectric conversion element, and a first switch. The storage battery has a positive electrode and a negative electrode and is capable of storing electric power. The thermoelectric conversion element is thermally connected to the storage battery and is capable of generating electric power through thermoelectric conversion. The first switch is provided in a path connecting the positive electrode and the negative electrode, has a control terminal to which electric power generated by the thermoelectric conversion element is applied, and is turned on based on the electric power generated by the thermoelectric conversion element, thereby discharging the storage battery.

[0007] According to the battery pack according to the embodiment of the present disclosure, safety can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram illustrating an example configuration of a battery pack according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is an explanatory diagram illustrating an example of the configuration of the battery pack shown in FIG. [Figure 3A] FIG. 3A is an explanatory diagram illustrating an example of an operation when controlling the temperature of the battery pack shown in FIG. [Figure 3B] FIG. 3B is an explanatory diagram showing another example of operation when controlling the temperature of the battery pack shown in FIG. [Figure 4A] FIG. 4A is an explanatory diagram showing an example of an operation when discharging the storage battery of the battery pack shown in FIG. [Figure 4B] FIG. 4B is an explanatory diagram showing another example of operation when discharging the storage battery of the battery pack shown in FIG. [Figure 5] FIG. 5 is a block diagram showing an example of the configuration of a battery pack according to a modified example. [Figure 6] FIG. 6 is a block diagram showing an example of the configuration of a battery pack according to a modified example. [Figure 7] FIG. 7 is a block diagram showing an example of the configuration of a battery pack according to a modified example. [Figure 8] FIG. 8 is a block diagram showing an example of the configuration of a battery pack according to a modified example. [Figure 9] FIG. 9 is a block diagram showing an example of the configuration of a battery pack according to a modified example. [Figure 10] FIG. 10 is a block diagram showing an example of the configuration of a battery pack according to a modified example. [Figure 11] FIG. 11 is a block diagram showing an example of the configuration of a battery pack according to a modified example. [Figure 12] FIG. 12 is a block diagram showing an example of the configuration of a battery pack according to a modified example. [Figure 13] FIG. 13 is a block diagram showing an example of the configuration of a battery pack according to a modified example. [Figure 14] FIG. 14 is a block diagram showing an example of the configuration of a battery pack according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] <Embodiment> [Configuration example] 1 and 2 show an example of the configuration of a battery pack (battery pack 1) according to one embodiment. In Fig. 1, battery pack 1 is connected to a charger 100. Battery pack 1 includes a storage battery 11, six Peltier elements 13 (Peltier elements 13A to 13F), a heat sink 14, a temperature sensor 15, a monitoring circuit 16, and a protection circuit 20. The storage battery 11, the six Peltier elements 13, the temperature sensor 15, the monitoring circuit 16, and the protection circuit 20 are housed inside a housing 90 (Fig. 2).

[0011] The storage battery 11 is configured to store power. The storage battery 11 has 24 battery cells 12. In this example, each of the 24 battery cells 12 is configured using a lithium-ion secondary battery. The 24 battery cells 12 are divided into six groups G (groups GA to GF). In each group G, four battery cells 12 are connected in parallel. The six groups G are connected in series. Specifically, the positive electrodes of four battery cells 12 belonging to group GA are connected to the negative electrodes of four battery cells 12 belonging to group GB, and the negative electrodes of four battery cells 12 belonging to group GA are connected to the negative electrode EN of the storage battery 11. The negative electrode EN of the storage battery 11 is connected to the negative terminal BN of the battery pack 1. The positive electrodes of four battery cells 12 belonging to group GB are connected to the negative electrodes of four battery cells 12 belonging to group GC, and the negative electrodes of four battery cells 12 belonging to group GB are connected to the positive electrodes of four battery cells 12 belonging to group GA. The positive electrodes of the four battery cells 12 belonging to group GC are connected to the negative electrodes of the four battery cells 12 belonging to group GD, and the negative electrodes of the four battery cells 12 belonging to group GC are connected to the positive electrodes of the four battery cells 12 belonging to group GB. The positive electrodes of the four battery cells 12 belonging to group GD are connected to the negative electrodes of the four battery cells 12 belonging to group GE, and the negative electrodes of the four battery cells 12 belonging to group GD are connected to the positive electrodes of the four battery cells 12 belonging to group GC. The positive electrodes of the four battery cells 12 belonging to group GE are connected to the negative electrodes of the four battery cells 12 belonging to group GF, and the negative electrodes of the four battery cells 12 belonging to group GE are connected to the positive electrodes of the four battery cells 12 belonging to group GD. The positive electrodes of the four battery cells 12 belonging to group GF are connected to the positive electrode EP of the storage battery 11, and the negative electrodes of the four battery cells 12 belonging to group GF are connected to the positive electrodes of the four battery cells 12 belonging to group GE. The positive electrode EP of the storage battery 11 is connected to the positive terminal BP of the battery pack 1.

[0012] Each of the 24 battery cells 12 has a cylindrical shape. As shown in Fig. 2, the 24 battery cells 12 are arranged side by side in the XY plane. Four battery cells 12 belonging to one group G are held by one cell holder 19. The cell holder 19 is made of, for example, a metal material and is capable of conducting heat.

[0013] Each of the six Peltier elements 13 has a plate shape and is configured to generate power according to the temperature difference between both surfaces. The Peltier elements 13 absorb or generate heat based on drive power supplied from outside the battery pack 1. The six Peltier elements 13A to 13F are connected in series. Specifically, the positive terminal of Peltier element 13A is connected to the negative terminal of Peltier element 13B, and the negative terminal of Peltier element 13A is connected to the negative terminal BN of the battery pack 1. The positive terminal of Peltier element 13B is connected to the negative terminal of Peltier element 13C, and the negative terminal of Peltier element 13B is connected to the positive terminal of Peltier element 13A. The positive terminal of Peltier element 13C is connected to the negative terminal of Peltier element 13D, and the negative terminal of Peltier element 13C is connected to the positive terminal of Peltier element 13B. The positive terminal of Peltier element 13D is connected to the negative terminal of Peltier element 13E, and the negative terminal of Peltier element 13D is connected to the positive terminal of Peltier element 13C. The positive terminal of Peltier element 13E is connected to the negative terminal of Peltier element 13F, and the negative terminal of Peltier element 13E is connected to the positive terminal of Peltier element 13D. The positive terminal of Peltier element 13F is connected to the positive terminal BP of battery pack 1, and the negative terminal of Peltier element 13F is connected to the positive terminal of Peltier element 13E.

[0014] Six Peltier elements 13A to 13F are provided corresponding to the six groups GA to GF of the storage battery 11, respectively. Each Peltier element 13 is thermally connected to four battery cells 12 belonging to the corresponding group G. Specifically, Peltier element 13A is thermally connected to four battery cells 12 belonging to group GA, Peltier element 13B is thermally connected to four battery cells 12 belonging to group GB, Peltier element 13C is thermally connected to four battery cells 12 belonging to group GC, Peltier element 13D is thermally connected to four battery cells 12 belonging to group GD, Peltier element 13E is thermally connected to four battery cells 12 belonging to group GE, and Peltier element 13F is thermally connected to four battery cells 12 belonging to group GF. In FIG. 1, dashed arrows indicate thermal connections.

[0015] 2, one surface S1 of the Peltier element 13 is thermally connected to the four battery cells 12 belonging to the corresponding group G via the cell holder 19, and the other surface S2 is thermally connected to the heat sink 14. This allows the Peltier element 13 to generate power according to the temperature difference between the outside air temperature and the temperature of the four battery cells 12 corresponding to that Peltier element 13. In addition, the Peltier element 13 can adjust the temperature of the four battery cells 12 by cooling or heating the four battery cells 12 corresponding to that Peltier element 13 based on the driving power supplied from the charger 100.

[0016] The heat sink 14 is configured to release heat generated in the storage battery 11 to the outside air or to supply heat from the outside air to the storage battery 11. As shown in FIG. 2 , the heat sink 14 is thermally connected to the outside air by contacting the outside air, and is thermally connected to the six Peltier elements 13 via the surfaces S2 of the six Peltier elements 13. In this example, the heat sink 14 has multiple fins. However, this is not a limitation, and the heat sink 14 can have various structures that can come into contact with the outside air. For example, the heat sink 14 may have multiple pins instead of multiple fins, or multiple blocks instead of multiple fins. Furthermore, the heat sink 14 may be, for example, a plate-shaped member provided on the outer surface of the housing 90 without multiple fins. Furthermore, while one heat sink 14 is provided in this example, this is not a limitation, and instead, for example, multiple heat sinks 14 may be provided. Specifically, for example, six heat sinks 14 may be provided, each thermally connected to one of the six Peltier elements 13.

[0017] The temperature sensor 15 includes, for example, a thermistor, and is configured to detect the temperature of the storage battery 11. The temperature sensor 15 is provided near the storage battery 11, for example.

[0018] The monitoring circuit 16 is configured to monitor the operating state of the battery pack 1. Specifically, the monitoring circuit 16 monitors, for example, the cell voltages of the 24 battery cells 12 in the storage battery 11 in groups G, and monitors the temperature of the storage battery 11. The monitoring circuit 16 is connected to the positive electrode EP and negative electrode EN of the storage battery 11 and operates based on power supplied from the storage battery 11. The monitoring circuit 16 monitors the operating state of the battery pack 1 when the battery pack 1 is connected to a charger 100 or an electronic device that operates by receiving power from the battery pack 1. Furthermore, when the battery pack 1 is not connected to the charger 100 or an electronic device that operates by receiving power from the battery pack 1, the monitoring circuit 16 operates in a sleep state. This improves safety and reduces power consumption in the battery pack 1.

[0019] The protection circuit 20 is configured to discharge the storage battery 11 when, for example, the battery pack 1 is not connected to the charger 100 and there is a large temperature difference between the outside air temperature and the temperature of the storage battery 11. Furthermore, when the battery pack 1 is connected to the charger 100, the protection circuit 20 is able to supply driving power supplied from the charger 100 to the Peltier elements 13A to 13F. The protection circuit 20 has a resistive element 21, a relay 22, a resistive element 23, a relay 24, and a resistive element 25.

[0020] One end of the resistance element 21 is connected to the drive terminal POWP of the battery pack 1, and the other end is connected to a control terminal C1 of the relay 22 (described later).

[0021] In this example, the relay 22 is an electromagnetic relay configured to connect terminal T1 to terminal T2 or terminal T3 by supplying power to the coil. When no power is supplied to the coil, terminal T1 is connected to terminal T3. When power is supplied to the coil, terminal T1 is connected to terminal T2, and then when power is no longer supplied to the coil, terminal T1 is connected to terminal T3. When power is supplied to the coil, the operation of the relay 22 is the same in both cases where current flows from control terminal C1 to control terminal C2 and where current flows from control terminal C2 to control terminal C1. In other words, the relay 22 is a non-polar relay.

[0022] In relay 22, terminal T1 is connected to the positive terminal of Peltier element 13F, terminal T2 is connected to drive terminal POWP of battery pack 1, and terminal T3 is connected to one end of resistive element 23. Control terminal C1, which is one end of the coil, is connected to the other end of resistive element 21, and control terminal C2, which is the other end of the coil, is connected to the negative terminal of Peltier element 13A and the negative terminal BN of battery pack 1.

[0023] One end of the resistive element 23 is connected to the terminal T3 of the relay 22, and the other end is connected to the control terminal C2 of the relay 24.

[0024] In this example, the relay 24 is an electromagnetic relay configured to connect terminal T1 to terminal T2 or terminal T3 by supplying power to the coil. When no power is supplied to the coil, terminal T1 is connected to terminal T3. When power is supplied to the coil, terminal T1 is connected to terminal T2, and even if power is subsequently removed from the coil, terminal T1 remains connected to terminal T2. In other words, the relay 24 is a latching relay. When power is supplied to the coil, the operation of the relay 22 is the same in both cases where current flows from control terminal C1 to control terminal C2 and where current flows from control terminal C2 to control terminal C1. In other words, the relay 22 is a non-polar relay.

[0025] In the relay 24, terminal T1 is connected to the resistive element 25, and terminal T2 is connected to the negative terminal EN of the storage battery 11 and to the negative terminal BN of the battery pack 1. Terminal T3 is in an open state and is not connected to any element. A control terminal C1, which is one end of the coil, is connected to the negative terminal of the Peltier element 13A and to the negative terminal BN of the battery pack 1, and a control terminal C2, which is the other end of the coil, is connected to the other end of the resistive element 23.

[0026] One end of the resistance element 25 is connected to the positive terminal EP of the storage battery 11 and to the positive terminal BP of the battery pack 1, and the other end is connected to the terminal T1 of the relay .

[0027] The charger 100 is configured to charge the battery pack 1. The charger 100 has a charging circuit 101 and a temperature control circuit 102. The charging circuit 101 is configured to charge the storage battery 11 of the battery pack 1 via the positive terminal BP and negative terminal BN of the battery pack 1. The temperature control circuit 102 is configured to supply driving power to the Peltier elements 13A to 13F via the driving terminal POWP and negative terminal BN of the battery pack 1, thereby controlling the temperature of the storage battery 11 of the battery pack 1 to a temperature suitable for a charging operation.

[0028] With this configuration, as shown in FIG. 1, when the battery pack 1 is connected to the charger 100, the Peltier elements 13A to 13F of the battery pack 1 adjust the temperature of the storage battery 11 by cooling or heating the storage battery 11 based on the driving power supplied from the temperature control circuit 102.

[0029] Furthermore, when the battery pack 1 is not connected to the charger 100, the Peltier elements 13A to 13F of the battery pack 1 generate power according to the temperature difference between the outside air temperature and the temperature of the storage battery 11. For example, if the battery pack 1 is placed near a heat source such as a fire, the outside air temperature may transiently become higher than the temperature of the storage battery 11, which may increase the power generated by the six Peltier elements 13. Similarly, if the battery pack 1 is damaged and begins to generate heat, the temperature of the storage battery 11 may transiently become higher than the outside air temperature, which may increase the power generated by the six Peltier elements 13. When the power generated by the six Peltier elements 13 is sufficiently high, the relay 24 connects the terminal T1 to the terminal T2. This causes the storage battery 11 to discharge in the battery pack 1. In this way, the battery pack 1 is designed to improve safety.

[0030] Here, the storage battery 11 corresponds to a specific example of a "storage battery" in an embodiment of the present disclosure. The positive electrode EP corresponds to a specific example of a "positive electrode" in an embodiment of the present disclosure. The negative electrode EN corresponds to a specific example of a "negative electrode" in an embodiment of the present disclosure. The heat sink 14 corresponds to a specific example of a "heat sink" in an embodiment of the present disclosure. The Peltier elements 13A to 13F correspond to a specific example of a "thermoelectric conversion element" in an embodiment of the present disclosure. The relay 24 corresponds to a specific example of a "first switch" in an embodiment of the present disclosure. The terminals T1, T2, and T3, and the control terminals C1 and C2 of the relay 24 correspond to specific examples of a "first terminal," a "second terminal," a "third terminal," and a "control terminal," respectively, of the "first switch" in an embodiment of the present disclosure. The relay 22 corresponds to a specific example of a "second switch" in an embodiment of the present disclosure. The terminals T1, T2, and T3 of the relay 22 and the control terminals C1 and C2 correspond to specific examples of a "first terminal," a "second terminal," a "third terminal," and a "control terminal" of a "second switch" in an embodiment of the present disclosure, respectively. The drive terminal POWP corresponds to a specific example of a "drive terminal" in an embodiment of the present disclosure. The monitoring circuit 16 corresponds to a specific example of a "monitoring circuit" in an embodiment of the present disclosure. The charger 100 corresponds to a specific example of a "device" in an embodiment of the present disclosure.

[0031] [Actions and Actions] Next, the operation and function of the battery pack 1 of this embodiment will be described.

[0032] (Overview of overall operation) First, an overview of the overall operation of the battery pack 1 will be described with reference to FIG. 1. The storage battery 11 stores power. Each of the six Peltier elements 13 generates power according to the temperature difference between the outside air temperature and the temperature of the four battery cells 12 corresponding to that Peltier element 13. The Peltier elements 13 also adjust the temperatures of the four battery cells 12 by cooling or heating the four battery cells 12 corresponding to that Peltier element 13 based on driving power supplied from outside the battery pack 1. The heat sink 14 releases heat generated in the storage battery 11 to the outside air or supplies heat from the outside air to the storage battery 11. The temperature sensor 15 detects the temperature of the storage battery 11. The monitoring circuit 16 monitors the operating state of the battery pack 1. When the battery pack 1 is connected to a charger 100, the protection circuit 20 supplies driving power supplied from the charger 100 to the Peltier elements 13A to 13F. Furthermore, for example, when the battery pack 1 is not connected to the charger 100, the protection circuit 20 discharges the storage battery 11 if there is a large temperature difference between the outside air temperature and the temperature of the storage battery 11.

[0033] (Detailed operation) First, the operation when the battery pack 1 is connected to the charger 100 will be described.

[0034] 3A and 3B show an example of operation when the battery pack 1 is connected to the charger 100, where FIG. 3A shows the case where the temperature of the storage battery 11 is high, and FIG. 3B shows the case where the temperature of the storage battery 11 is low.

[0035] The charger 100 grasps the temperature of the storage battery 11, for example, by communicating with the monitoring circuit 16 of the battery pack 1. Then, the temperature control circuit 102 of the charger 100 generates driving power based on the temperature of the storage battery 11.

[0036] When the temperature of the storage battery 11 is high, the temperature control circuit 102 supplies drive power via the drive terminal POWP and the negative terminal BN such that the voltage of the drive terminal POWP is higher than the voltage of the negative terminal BN. As a result, as shown in FIG. 3A, a current I1 flows through the drive terminal POWP, the resistive element 21, the coil of the relay 22, and the negative terminal BN in this order, and the relay 22 connects terminal T1 to terminal T2. As a result, the drive terminal POWP is connected to the positive terminal of the Peltier element 13F via the relay 22. A drive current I2 then flows through the drive terminal POWP, the relay 22, the six Peltier elements 13, and the negative terminal BN in this order. The six Peltier elements 13 cool the storage battery 11 based on this drive current I2.

[0037] When the temperature of the storage battery 11 is low, the temperature control circuit 102 supplies drive power via the drive terminal POWP and the negative terminal BN such that the voltage of the drive terminal POWP is lower than the voltage of the negative terminal BN. As a result, as shown in FIG. 3B , a current I3 flows in the order of the negative terminal BN, the coil of the relay 22, the resistive element 21, and the drive terminal POWP, and the relay 22 connects the terminal T1 to the terminal T2. As a result, the drive terminal POWP is connected to the positive terminal of the Peltier element 13F via the relay 22. Then, a drive current I4 flows in the order of the negative terminal BN, the six Peltier elements 13, the relay 22, and the drive terminal POWP. The six Peltier elements 13 heat the storage battery 11 based on this drive current I4.

[0038] In this way, the temperature control circuit 102 controls the temperature of the storage battery 11 so that the temperature becomes suitable for the charging operation.

[0039] The charging circuit 101 of the charger 100 then supplies charging power to the battery pack 1. As a result, as shown in Figures 3A and 3B, a charging current I5 flows in the order of the positive terminal BP, the storage battery 11, and the negative terminal BN. In this way, the charging circuit 101 charges the storage battery 11.

[0040] In this battery pack 1, the resistive element 21 is provided to prevent the terminal T1 of the relay 22 from being connected to the terminal T2 due to the power generated by the six Peltier elements 13. That is, for example, as shown in FIGS. 3A and 3B , when the charger 100 supplies drive power to the battery pack 1 and then stops the supply of drive power, a current may flow through the coil of the relay 22 based on the power generated by the six Peltier elements 13. If the resistive element 21 were not provided, a larger amount of power would be supplied to the coil, which could potentially connect the terminal T1 of the relay 22 to the terminal T2. The battery pack 1 is provided with the resistive element 21, which can limit the power supplied to the coil. As a result, the battery pack 1 can prevent the terminal T1 of the relay 22 from being connected to the terminal T2 due to the power generated by the six Peltier elements 13.

[0041] Next, we will explain the operation when the battery pack 1 is not connected to the charger 100. Because the battery pack 1 is not connected to the charger 100 or any electronic device that operates by receiving power from the battery pack 1, the monitoring circuit 16 operates in a sleep state and simply monitors, for example, the operating state of the battery pack 1. Because nothing is connected to the drive terminal POWP, almost no current flows through the coil of the relay 22. Therefore, the relay 22 connects the terminal T1 to the terminal T3. As a result, the positive terminal of the Peltier element 13F is connected to the control terminal C2 of the relay 24 via the relay 22 and the resistive element 23. Each of the six Peltier elements 13 generates power according to the temperature difference between the outside air temperature and the temperatures of the four battery cells 12 corresponding to that Peltier element 13.

[0042] For example, if the battery pack 1 is placed near a heat source such as a fire, the temperature of the outside air may transiently become higher than the temperature of the storage battery 11, which may increase the power generated by the six Peltier elements 13. Similarly, if the battery pack 1 is damaged and begins to generate heat, the temperature of the storage battery 11 may transiently become higher than the temperature of the outside air, which may increase the power generated by the six Peltier elements 13. If the power generated by the six Peltier elements 13 is large enough to operate the relay 24, the relay 24 connects terminal T1 to terminal T2 and discharges the storage battery 11.

[0043] 4A and 4B show an example of a discharging operation, where FIG. 4A shows a case where the temperature of the outside air is sufficiently higher than the temperature of the storage battery 11, and FIG. 4B shows a case where the temperature of the storage battery 11 is sufficiently higher than the temperature of the outside air.

[0044] When the outside air temperature is higher than the temperature of the storage battery 11, the six Peltier elements 13 generate power with a higher polarity in the voltage of their positive terminals than in the voltage of their negative terminals. As a result, as shown in FIG. 4A, a current I11 flows from the positive terminal of the Peltier element 13F to the relay 22, the resistor element 23, the coil of the relay 24, and the negative terminal of the Peltier element 13A in this order. When the power generated by the six Peltier elements 13 is large enough to operate the relay 24, the relay 24 connects the terminal T1 to the terminal T2, as shown in FIG. 4A. As a result, a discharge current I13 flows from the positive terminal EP of the storage battery 11 to the resistor element 25, the relay 24, and the negative terminal EN of the storage battery 11 in this order, thereby discharging the storage battery 11. Because the relay 24 is a latching relay, the terminal T1 remains connected to the terminal T2. This allows the storage battery 11 to be sufficiently discharged.

[0045] When the temperature of the storage battery 11 is higher than the outside air temperature, the six Peltier elements 13 generate power with a higher polarity at their negative terminals than at their positive terminals. As a result, as shown in FIG. 4B, a current I12 flows from the negative terminal of the Peltier element 13A to the coil of the relay 24, the resistor element 23, the relay 22, and the positive terminal of the Peltier element 13F, in that order. When the power generated by the six Peltier elements 13 is large enough to operate the relay 24, the relay 24 connects the terminal T1 to the terminal T2, as shown in FIG. 4B. As a result, a discharge current I13 flows from the positive terminal EP of the storage battery 11 to the resistor element 25, the relay 24, and the negative terminal EN of the storage battery 11, in that order, thereby discharging the storage battery 11. Because the relay 24 is a latching relay, even if the power generated by the six Peltier elements 13 decreases, the terminal T1 remains connected to the terminal T2. This allows the storage battery 11 to be sufficiently discharged.

[0046] In this battery pack 1, the resistive element 23 is provided to adjust the current I12, as shown in Figures 4A and 4B. That is, the relay 24 operates based on the power generated by the six Peltier elements 13. Therefore, the resistive element 23 can adjust the power supplied to the relay 24. Note that if the power generated by the six Peltier elements 13 is sufficient to operate the relay 24 appropriately, the resistive element 23 may be omitted.

[0047] 4A and 4B, the resistive element 25 is provided to adjust the discharge current I13. That is, in the battery pack 1, the resistive element 25 can adjust the discharge rate during the discharging operation. Note that, for example, if an appropriate discharge rate can be achieved due to the characteristics of the storage battery 11, the resistive element 25 may be omitted.

[0048] As described above, the battery pack 1 includes a storage battery 11 having a positive electrode EP and a negative electrode EN and capable of storing electric power; thermoelectric conversion elements (six Peltier elements 13) thermally connected to the storage battery 11 and capable of generating electric power through thermoelectric conversion; and a first switch (relay 24) provided in a path connecting the positive electrode EP and the negative electrode EN, having control terminals C1 and C2 to which electric power generated by the thermoelectric conversion elements (six Peltier elements 13) is applied, and turning on based on the electric power generated by the thermoelectric conversion elements (six Peltier elements 13) to discharge the storage battery 11. As a result, in the battery pack 1, for example, if the battery pack 1 is placed near a heat source such as a fire or if the battery pack 1 is damaged and begins to generate heat, the electric power generated by the six Peltier elements 13 transiently increases. Then, in the battery pack 1, the relay 24 turns on based on this electric power, allowing the storage battery 11 to be discharged. As a result, the battery pack 1 can improve safety.

[0049] The battery pack 1 further includes a monitoring circuit 16 that can monitor the operating state of the battery pack 1 when the battery pack 1 is connected to a device (such as a charger 100 or an electronic device that operates by receiving power from the battery pack 1) and can operate in a sleep state when the battery pack 1 is not connected to the device. In this way, the monitoring circuit 16 has difficulty detecting the operating state of the battery pack 1 when operating in a sleep state. Even in such a case, the battery pack 1 can discharge the storage battery 11 based on the power corresponding to the temperature difference between the outside air temperature and the temperature of the storage battery 11. As a result, the battery pack 1 can improve safety.

[0050] Furthermore, even if the monitoring circuit 16 fails, for example, if the battery pack 1 is placed near a heat source such as a fire, or if the battery pack 1 is damaged and begins to generate heat, the storage battery 11 can be discharged based on the power generated by the six Peltier elements 13. Therefore, the battery pack 1 can improve safety.

[0051] The monitoring circuit 16 operates based on the power stored in the storage battery 11. Therefore, even if the battery pack 1 is not connected to the charger 100 or an electronic device that operates by receiving power from the battery pack 1, if the monitoring circuit 16 monitors the operating state of the battery pack 1, the longer the storage period, the lower the SOC (State Of Charge) value of the storage battery 11. The battery pack 1 can operate based on the power generated by the six Peltier elements 13, rather than the power stored in the storage battery 11, and therefore, the lowering of the SOC value of the storage battery 11 can be suppressed during the storage period.

[0052] In the battery pack 1, the first switch (relay 24) is configured to be able to maintain the on state after being turned on based on the power generated by the thermoelectric conversion elements (six Peltier elements 13). This allows the battery pack 1 to maintain a state in which the storage battery 11 is discharged even when, for example, the battery pack 1 approaches a thermal equilibrium state and the power generated by the six Peltier elements 13 becomes small. This allows the storage battery 11 to be sufficiently discharged in the battery pack 1, thereby improving safety.

[0053] The battery pack 1 further includes a drive terminal POWP to which drive power can be supplied, and a second switch (relay 22). The thermoelectric conversion elements (six Peltier elements 13) include Peltier elements. The second switch (relay 22) is capable of supplying drive power to the thermoelectric conversion elements (six Peltier elements 13). The first switch (relay 24) is capable of discharging the storage battery 11 when the second switch (relay 22) is not supplying drive power to the thermoelectric conversion elements (six Peltier elements 13). Specifically, in the battery pack 1, for example, the second switch (relay 22) has a first terminal (terminal T1) connected to the thermoelectric conversion elements (six Peltier elements 13), a second terminal (terminal T2) connected to the drive terminal POWP, a third terminal (terminal T3) connected to the control terminal (control terminal C2) of the first switch (relay 24), and a control terminal (control terminal C1) connected to the drive terminal POWP. When drive power is supplied to the drive terminal POWP, the second switch (relay 22) can connect the first terminal (terminal T1) and the second terminal (terminal T2) to each other, and when drive power is not supplied to the drive terminal POWP, the second switch (relay 22) can connect the first terminal (terminal T1) and the third terminal (terminal T3) to each other. As a result, when the battery pack 1 receives external driving power, the driving power is supplied to the six Peltier elements 13 to cool or warm the storage battery 11, thereby adjusting the temperature of the storage battery 11. Furthermore, when the battery pack 1 does not receive external driving power, the storage battery 11 can be discharged based on the power generated by the six Peltier elements 13. In this way, the battery pack 1 can effectively utilize the six Peltier elements 13.

[0054] [effect] As described above, in this embodiment, a storage battery having a positive electrode and a negative electrode and capable of storing electric power, a thermoelectric conversion element thermally connected to the storage battery and capable of generating electric power through thermoelectric conversion, and a first switch provided in a path connecting the positive electrode and the negative electrode, having a control terminal to which the electric power generated by the thermoelectric conversion element is applied, and turning on based on the electric power generated by the thermoelectric conversion element, thereby enabling the storage battery to be discharged, are provided, thereby improving safety.

[0055] In this embodiment, the operating state of the battery pack can be monitored when the battery pack is connected to a device, and a monitoring circuit is further provided that can operate in a sleep state when the battery pack is not connected to a device, thereby improving safety.

[0056] In this embodiment, the first switch is configured to be able to maintain the on state after being turned on based on the power generated by the thermoelectric conversion element, thereby improving safety.

[0057] In this embodiment, a drive terminal to which drive power can be supplied and a second switch are further provided. The thermoelectric conversion element includes a Peltier element. The second switch is capable of supplying drive power to the thermoelectric conversion element. The first switch is capable of discharging the storage battery when the second switch is not supplying drive power to the thermoelectric conversion element. Specifically, for example, the second switch has a first terminal connected to the thermoelectric conversion element, a second terminal connected to the drive terminal, a third terminal connected to the control terminal of the first switch, and a control terminal connected to the drive terminal. The second switch is capable of connecting the first and second terminals to each other when drive power is supplied to the drive terminal, and is capable of connecting the first and third terminals to each other when drive power is not supplied to the drive terminal. This allows the thermoelectric conversion element to be used effectively.

[0058] [Variation 1] In the above embodiment, the temperature control circuit 102 supplies drive power to the Peltier elements 13A to 13F via the drive terminal POWP and the negative terminal BN of the battery pack 1, but this is not limitative. Below, this modified example will be described with some examples.

[0059] FIG. 5 shows an example of the configuration of a battery pack 1A and a charger 100A according to this modification.

[0060] The charger 100A has a temperature control circuit 102A. The temperature control circuit 102A is configured to control the temperature of the storage battery 11 of the battery pack 1A to a temperature suitable for charging by supplying drive power to the Peltier elements 13A to 13F via the positive terminal BP and drive terminal POWN of the battery pack 1A.

[0061] The battery pack 1A includes a protection circuit 20A, which includes a resistive element 21, a relay 22, a resistive element 23, a relay 24, and a resistive element 25.

[0062] One end of the resistor element 21 is connected to the positive terminal BP, and the other end is connected to the control terminal C1 of the relay 22.

[0063] Terminal T1 of relay 22 is connected to the positive terminal of Peltier element 13F, terminal T2 is connected to the positive terminal BP, and terminal T3 is connected to one end of resistor element 23. Control terminal C1, which is one end of the coil, is connected to the other end of resistor element 21, and control terminal C2, which is the other end of the coil, is connected to the negative terminal of Peltier element 13A and to drive terminal POWN of battery pack 1A.

[0064] One end of the resistive element 23 is connected to the terminal T3 of the relay 22, and the other end is connected to the control terminal C2 of the relay 24.

[0065] Terminal T1 of relay 24 is connected to resistive element 25, terminal T2 is connected to the negative terminal EN of storage battery 11 and to the negative terminal BN of battery pack 1A. Terminal T3 is in an open state and is not connected to any element. Control terminal C1, which is one end of the coil, is connected to the negative terminal of Peltier element 13A and to the drive terminal POWN of battery pack 1A, and control terminal C2, which is the other end of the coil, is connected to the other end of resistive element 23.

[0066] One end of the resistance element 25 is connected to the positive terminal EP of the storage battery 11 and to the positive terminal BP of the battery pack 1A, and the other end is connected to the terminal T1 of the relay 24.

[0067] When the temperature of the storage battery 11 is high, the temperature control circuit 102A supplies drive power via the positive terminal BP and the drive terminal POWN such that the voltage at the drive terminal POWN is lower than the voltage at the positive terminal BP. This is applied to the drive terminal POWN. This causes current to flow through the positive terminal BP, the resistive element 21, the coil of the relay 22, and the drive terminal POWN in this order, and the relay 22 connects terminal T1 to terminal T2. This connects the positive terminal BP to the positive terminal of the Peltier element 13F via the relay 22. This drive current then flows through the positive terminal BP, the relay 22, the six Peltier elements 13, and the drive terminal POWN in this order. The six Peltier elements 13 cool the storage battery 11 based on this drive current.

[0068] When the temperature of the storage battery 11 is low, the temperature control circuit 102A supplies drive power via the positive terminal BP and the drive terminal POWN such that the voltage at the drive terminal POWN is higher than the voltage at the positive terminal BP. As a result, current flows from the drive terminal POWN to the coil of the relay 22, the resistance element 21, and the positive terminal BP in that order, and the relay 22 connects terminal T1 to terminal T2. As a result, the positive terminal BP is connected to the positive terminal of the Peltier element 13F via the relay 22. Then, a drive current flows from the drive terminal POWN to the six Peltier elements 13, the relay 22, and the positive terminal BP in that order. The six Peltier elements 13 heat the storage battery 11 based on this drive current.

[0069] FIG. 6 shows an example of the configuration of another battery pack 1B and another charger 100B according to this modification.

[0070] The charger 100B has a temperature control circuit 102B. The temperature control circuit 102B is configured to control the temperature of the storage battery 11 of the battery pack 1B to a temperature suitable for charging by supplying drive power to the Peltier elements 13A-13F via the drive terminal POWP and the positive terminal BP of the battery pack 1B.

[0071] The battery pack 1B includes a protection circuit 20B, which includes a resistive element 21, a relay 22, a resistive element 23, a relay 24, and a resistive element 25.

[0072] One end of the resistance element 21 is connected to the drive terminal POWP, and the other end is connected to the control terminal C1 of the relay 22.

[0073] Terminal T1 of relay 22 is connected to the positive terminal of Peltier element 13F, terminal T2 is connected to drive terminal POWP, and terminal T3 is connected to one end of resistor element 23. Control terminal C1, which is one end of the coil, is connected to the other end of resistor element 21, and control terminal C2, which is the other end of the coil, is connected to the negative terminal of Peltier element 13A and the positive terminal BP of battery pack 1B.

[0074] One end of the resistive element 23 is connected to the terminal T3 of the relay 22, and the other end is connected to the control terminal C2 of the relay 24.

[0075] Terminal T1 of relay 24 is connected to the positive terminal EP of storage battery 11, and terminal T2 is connected to one end of resistor element 25. Terminal T3 is in an open state and is not connected to any element. Control terminal C1, which is one end of the coil, is connected to the negative terminal of Peltier element 13A and the positive terminal BP of battery pack 1B, and control terminal C2, which is the other end of the coil, is connected to the other end of resistor element 23.

[0076] One end of the resistive element 25 is connected to the terminal T2 of the relay 24, and the other end is connected to the negative terminal EN of the storage battery 11 and to the negative terminal BN of the battery pack 1B.

[0077] When the temperature of the storage battery 11 is high, the temperature control circuit 102B supplies drive power via the drive terminal POWP and the positive terminal BP such that the voltage of the drive terminal POWP is higher than the voltage of the positive terminal BP. As a result, current flows from the drive terminal POWP to the resistive element 21, the coil of the relay 22, and the positive terminal BP in that order, and the relay 22 connects terminal T1 to terminal T2. As a result, the drive terminal POWP is connected to the positive terminal of the Peltier element 13F via the relay 22. Then, a drive current flows from the drive terminal POWP to the relay 22, the six Peltier elements 13, and the positive terminal BP in that order. The six Peltier elements 13 cool the storage battery 11 based on this drive current.

[0078] When the temperature of the storage battery 11 is low, the temperature control circuit 102B supplies drive power via the drive terminal POWP and the positive terminal BP such that the voltage at the drive terminal POWP is lower than the voltage at the positive terminal BP. As a result, current flows in the order of the positive terminal BP, the coil of the relay 22, the resistance element 21, and the drive terminal POWP, and the relay 22 connects terminal T1 to terminal T2. As a result, the drive terminal POWP is connected to the positive terminal of the Peltier element 13F via the relay 22. Then, a drive current flows in the order of the positive terminal BP, the six Peltier elements 13, the relay 22, and the drive terminal POWP. The six Peltier elements 13 heat the storage battery 11 based on this drive current.

[0079] FIG. 7 shows an example of the configuration of another battery pack 1C and another charger 100C according to this modification.

[0080] The charger 100C has a temperature control circuit 102C. The temperature control circuit 102C is configured to control the temperature of the storage battery 11 of the battery pack 1C to a temperature suitable for charging operation by supplying driving power to the Peltier elements 13A to 13F via the driving terminals POWP and POWN of the battery pack 1C.

[0081] The battery pack 1C includes a protection circuit 20C, which includes a resistive element 21, a relay 22, a resistive element 23, a relay 24, and a resistive element 25.

[0082] One end of the resistance element 21 is connected to the drive terminal POWP, and the other end is connected to the control terminal C1 of the relay 22.

[0083] Terminal T1 of relay 22 is connected to the positive terminal of Peltier element 13F, terminal T2 is connected to drive terminal POWP, and terminal T3 is connected to one end of resistor element 23. Control terminal C1, which is one end of the coil, is connected to the other end of resistor element 21, and control terminal C2, which is the other end of the coil, is connected to the negative terminal of Peltier element 13A and to drive terminal POWN of battery pack 1C.

[0084] One end of the resistive element 23 is connected to the terminal T3 of the relay 22, and the other end is connected to the control terminal C2 of the relay 24.

[0085] Terminal T1 of relay 24 is connected to resistive element 25 and to the positive terminal BP of battery pack 1C, terminal T2 is connected to the negative terminal EN of storage battery 11 and to the negative terminal BN of battery pack 1C. Terminal T3 is in an open state and is not connected to any element. Control terminal C1, which is one end of the coil, is connected to the negative terminal of Peltier element 13A and to the drive terminal POWN of battery pack 1C, and control terminal C2, which is the other end of the coil, is connected to the other end of resistive element 23.

[0086] One end of the resistance element 25 is connected to the positive electrode EP of the storage battery 11, and the other end is connected to the terminal T1 of the relay .

[0087] When the temperature of the storage battery 11 is high, the temperature control circuit 102C supplies drive power via the drive terminals POWP and POWN such that the voltage of the drive terminal POWP is higher than the voltage of the drive terminal POWN. As a result, current flows from the drive terminal POWP to the resistor element 21, the coil of the relay 22, and the drive terminal POWN in that order, and the relay 22 connects terminal T1 to terminal T2. As a result, the drive terminal POWP is connected to the positive terminal of the Peltier element 13F via the relay 22. Then, a drive current flows from the drive terminal POWP to the relay 22, the six Peltier elements 13, and the drive terminal POWN in that order. The six Peltier elements 13 cool the storage battery 11 based on this drive current.

[0088] When the temperature of the storage battery 11 is low, the temperature control circuit 102C supplies drive power via the drive terminals POWP and POWN such that the voltage at the drive terminal POWP is lower than the voltage at the drive terminal POWN. As a result, current flows from the drive terminal POWN to the coil of the relay 22, the resistance element 21, and the drive terminal POWP in that order, and the relay 22 connects terminal T1 to terminal T2. As a result, the drive terminal POWP is connected to the positive terminal of the Peltier element 13F via the relay 22. Then, a drive current flows from the drive terminal POWN to the six Peltier elements 13, the relay 22, and the drive terminal POWP in that order. The six Peltier elements 13 heat the storage battery 11 based on this drive current.

[0089] [Variation 2] In the above embodiment, the temperature control circuit 102 drives the six Peltier elements 13 to cool or warm the storage battery 11, but this is not limiting. Alternatively, for example, the temperature control circuit 102 may only cool the storage battery 11. In this case, the relay 22 may be configured using a polarized relay. When power is supplied to the coil of the polarized relay 22, if a current flows from the control terminal C1 to the control terminal C2, the relay 22 connects the terminal T1 to the terminal T2. On the other hand, when a current flows from the control terminal C2 to the control terminal C1, the operation is the same as when no power is supplied to the coil, and the relay 22 connects the terminal T1 to the terminal T3.

[0090] [Variation 3] In the above embodiment, non-polar relays 22, 24 are used, but this is not limiting, and instead, for example, polarized relays 22, 24 may be used. Fig. 8 shows an example configuration of a battery pack 1D according to this modification. The battery pack 1D has a protection circuit 20D. The protection circuit 20D has a relay 22D, diodes D1 to D4, a relay 24D, and diodes D11 to D14.

[0091] Relay 22D is a polarized relay. When power is supplied to the coil of relay 22D, if a current flows from control terminal C1 to control terminal C2, relay 22D connects terminal T1 to terminal T2. On the other hand, when a current flows from control terminal C2 to control terminal C1, the operation is the same as when power is not supplied to the coil, and relay 22D connects terminal T1 to terminal T3.

[0092] The diodes D1 to D4 are bridge diodes. The anode of the diode D1 is connected to the other end of the resistor element 21, and the cathode is connected to the control terminal C1 of the relay 22D. The anode of the diode D2 is connected to the negative terminal of the Peltier element 13A and the negative terminal BN of the battery pack 1D, and the cathode is connected to the control terminal C1 of the relay 22D. The anode of the diode D3 is connected to the control terminal C2 of the relay 22D, and the cathode is connected to the negative terminal of the Peltier element 13A and the negative terminal BN of the battery pack 1D. The anode of the diode D4 is connected to the control terminal C2 of the relay 22D, and the cathode is connected to the other end of the resistor element 21. Here, the diode D1 corresponds to a specific example of a "fifth diode" in an embodiment of the present disclosure. The diode D2 corresponds to a specific example of a "sixth diode" in an embodiment of the present disclosure. The diode D3 corresponds to a specific example of a "seventh diode" in an embodiment of the present disclosure. Diode D4 corresponds to a specific example of an "eighth diode" in an embodiment of the present disclosure. Drive terminal POWP corresponds to a specific example of a "first drive terminal" in an embodiment of the present disclosure. Negative terminal BN corresponds to a specific example of a "second drive terminal" in an embodiment of the present disclosure.

[0093] 3A in the above embodiment, when the temperature control circuit 102 supplies drive power via the drive terminal POWP and the negative terminal BN such that the voltage of the drive terminal POWP is higher than the voltage of the negative terminal BN, current flows in the order of the drive terminal POWP, the resistive element 21, the diode D1, the coil of the relay 22D, the diode D3, and the negative terminal BN. As a result, the relay 22D connects the terminal T1 to the terminal T2, and the temperature control circuit 102 can drive six Peltier elements 13.

[0094] 3B of the above embodiment, when the temperature control circuit 102 supplies drive power via the drive terminal POWP and the negative terminal BN such that the voltage of the drive terminal POWP is lower than the voltage of the negative terminal BN, current flows in the order of the negative terminal BN, diode D2, the coil of the relay 22D, diode D4, resistor element 21, and drive terminal POWP. As a result, relay 22D connects terminal T1 to terminal T2, and the temperature control circuit 102 becomes able to drive six Peltier elements 13.

[0095] Relay 24D is a polarized relay. When power is supplied to the coil of relay 24D, if a current flows from control terminal C1 to control terminal C2, relay 24D connects terminal T1 to terminal T2. On the other hand, when a current flows from control terminal C2 to control terminal C1, the operation is the same as when power is not supplied to the coil, and relay 24D connects terminal T1 to terminal T3.

[0096] The diodes D11 to D14 are bridge diodes. The anode of the diode D11 is connected to the other end of the resistor element 23, and the cathode is connected to the control terminal C1 of the relay 24D. The anode of the diode D12 is connected to the negative terminal of the Peltier element 13A and the negative terminal BN of the battery pack 1D, and the cathode is connected to the control terminal C1 of the relay 24D. The anode of the diode D13 is connected to the control terminal C2 of the relay 24D, and the cathode is connected to the negative terminal of the Peltier element 13A and the negative terminal BN of the battery pack 1D. The anode of the diode D14 is connected to the control terminal C2 of the relay 24D, and the cathode is connected to the other end of the resistor element 23. Here, the diode D11 corresponds to a specific example of a "first diode" in an embodiment of the present disclosure. The diode D12 corresponds to a specific example of a "second diode" in an embodiment of the present disclosure. The diode D13 corresponds to a specific example of a "third diode" in an embodiment of the present disclosure. The diode D14 corresponds to a specific but not limitative example of a "fourth diode" in an embodiment of the present disclosure.

[0097] 4A in the above embodiment, when six Peltier elements 13 generate power with a higher polarity in which the voltage at the positive terminal is higher than the voltage at the negative terminal, current flows in the order of the positive terminal of Peltier element 13F, relay 22D, resistive element 23, diode D11, the coil of relay 24D, diode D13, and the negative terminal of Peltier element 13A. As a result, relay 24D connects terminal T1 to terminal T2, and storage battery 11 is discharged.

[0098] 4B in the above embodiment, when six Peltier elements 13 generate power with a higher polarity in the voltage of the negative terminal than in the voltage of the positive terminal, current flows in the order of the negative terminal of Peltier element 13A, diode D12, the coil of relay 24D, diode D14, resistive element 23, relay 22D, and the positive terminal of Peltier element 13F. As a result, relay 24D connects terminal T1 to terminal T2, and storage battery 11 is discharged.

[0099] [Variation 4] In the above embodiment, the relay 22 operates based on the driving power generated by the temperature control circuit 102, but this is not limiting. Alternatively, the relay 22 may operate based on, for example, other driving power. FIG. 9 illustrates a configuration example of a battery pack 1E according to this modification. The battery pack 1E includes a protection circuit 20E. In the protection circuit 20E, the control terminal C1 of the relay 22 is connected to the terminal BATT. Here, the terminal BATT corresponds to a specific example of a "control signal terminal" in an embodiment of the present disclosure. The battery pack 1E is connected to a charger 100E. When the battery pack 1E is connected to the charger 100E, the charging circuit 101E of the charger 100E applies a predetermined voltage to the terminal BATT. That is, the battery pack 1E can detect whether the charger 100E is connected to the battery pack 1E based on the voltage at the terminal BATT. When the charger 100E is connected to the battery pack 1E, current flows in the order of terminal BATT, the coil of the relay 22, and the negative terminal BN in the battery pack 1E, and the relay 22 connects terminal T1 to terminal T2. This allows the temperature control circuit 102 to drive the six Peltier elements 13. Furthermore, when the charger 100E is not connected to the battery pack 1E, no power is supplied to the coil of the relay 22, so the relay 22 connects terminal T1 to terminal T3. Therefore, in the battery pack 1E, the storage battery 11 can be discharged based on the power generated by the six Peltier elements 13.

[0100] [Variation 5] In the above embodiment, the power generated by the six Peltier elements 13 is directly supplied to the coil of the relay 24, but this is not limiting. Alternatively, a circuit may supply power to the coil of the relay 24 based on the power generated by the six Peltier elements 13. This modification will be described in detail using several examples.

[0101] 10 shows an example of the configuration of a battery pack 1F according to this modification. The battery pack 1F includes a protection circuit 20F. The protection circuit 20F includes a relay 22, a switch control circuit 30F, a relay 24, and a resistance element 25. The switch control circuit 30F includes diodes D21 to D24, resistance elements 31 and 32, a control circuit 33, a resistance element 34, and a transistor 35.

[0102] Terminal T1 of relay 22 is connected to the positive terminal of Peltier element 13F, terminal T2 is connected to drive terminal POWP, and terminal T3 is connected to the anode of diode D21 and the cathode of diode D24. Control terminal C1, which is one end of the coil, is connected to terminal BATT, and control terminal C2, which is the other end of the coil, is connected to negative terminal BN of battery pack 1F.

[0103] The anode of diode D21 is connected to terminal T3 of relay 22, and the cathode is connected to one end of resistor 31. The anode of diode D22 is connected to the negative terminal of Peltier element 13A, and the cathode is connected to one end of resistor 31. The anode of diode D23 is connected to negative terminal BN, and the cathode is connected to the negative terminal of Peltier element 13A. The anode of diode D24 is connected to negative terminal BN, and the cathode is connected to terminal T3 of relay 22.

[0104] One end of the resistor element 31 is connected to the cathodes of the diodes D21 and D22, and the other end is connected to the node N1. One end of the resistor element 32 is connected to the node N1, and the other end is connected to the negative terminal BN of the battery pack 1F.

[0105] The control circuit 33 is configured to compare the voltage at the terminal IN with a predetermined threshold voltage, and to set the voltage at the terminal OUT to a high level when the voltage at the terminal IN is higher than the predetermined threshold voltage, and to set the voltage at the terminal OUT to a low level when the voltage at the terminal IN is lower than the predetermined threshold voltage. The terminal IN of the control circuit 33 is connected to the node N1, and the terminal OUT is connected to one end of the resistor 34 and the gate of the transistor 35. The control circuit 33 is connected to the positive electrode EP and negative electrode EN of the storage battery 11, and is configured to operate based on power supplied from the storage battery 11.

[0106] One end of the resistor element 34 is connected to the terminal OUT of the control circuit 33, and the other end is connected to the negative terminal BN of the battery pack 1F. The transistor 35 is an N-type field effect transistor, and has a drain connected to the control terminal C2 of the relay 24, a gate connected to the terminal OUT of the control circuit 33, and a source connected to the negative terminal BN of the battery pack 1F.

[0107] Terminal T1 of relay 24 is connected to resistor element 25, terminal T2 is connected to the negative terminal EN of storage battery 11 and to the negative terminal BN of battery pack 1F. Terminal T3 is in an open state and is not connected to any element. Control terminal C1, which is one end of the coil, is connected to the positive terminal EP of storage battery 11 and to the positive terminal BP of battery pack 1F, and control terminal C2, which is the other end of the coil, is connected to the drain of transistor 35.

[0108] One end of the resistance element 25 is connected to the positive terminal EP of the storage battery 11 and to the positive terminal BP of the battery pack 1, and the other end is connected to the terminal T1 of the relay .

[0109] Here, the switch control circuit 30F corresponds to a specific but not limitative example of "switch control circuit" in an embodiment of the present disclosure.

[0110] 4A in the above embodiment, when six Peltier elements 13 generate power with a higher polarity in which the voltage at the positive terminal is higher than the voltage at the negative terminal, current flows in the order of the positive terminal of Peltier element 13F, relay 22, diode D21, resistor element 31, resistor element 32, and negative terminal of Peltier element 13A. When the voltage at node N1 is higher than the threshold voltage, control circuit 33 sets the voltage at terminal OUT to a high level.

[0111] 4B in the above embodiment, when six Peltier elements 13 generate power with a higher polarity in which the voltage at the negative terminal is higher than the voltage at the positive terminal, current flows in the order of the negative terminal of Peltier element 13A, diode D22, resistor element 31, resistor element 32, diode D24, relay 22, and the positive terminal of Peltier element 13F. When the voltage at node N1 is higher than the threshold voltage, control circuit 33 sets the voltage at terminal OUT to a high level.

[0112] When the voltage at the terminal OUT becomes high, the transistor 35 turns on, and current flows from the positive electrode EP of the storage battery 11 to the coil of the relay 24, the transistor 35, and the negative electrode EN of the storage battery 11 in this order, and the relay 24 connects the terminal T1 to the terminal T2, causing the storage battery 11 to discharge.

[0113] In this battery pack 1F, the resistive elements 31 and 32 are provided to divide the voltage corresponding to the power generated by the six Peltier elements 13. If this voltage division is not necessary, the resistive element 31 can be omitted.

[0114] In this way, the battery pack 1F is provided with a switch control circuit 30F that can turn on the first switch (relay 24) by driving the control terminals (control terminals C1 and C2) of the first switch (relay 24) based on the power generated by the thermoelectric conversion elements (six Peltier elements 13). This allows the storage battery 11 to be stably discharged without being affected by individual differences in the relay 24. That is, there are individual differences in the power that needs to be supplied to the coil to turn on the relay 24. In this case, there may be variations in the temperature difference at which the storage battery 11 starts discharging among the six Peltier elements 13. In the battery pack 1F, when the voltage of node N1 is higher than the threshold voltage, the control circuit 33 sets the voltage of the terminal OUT to a high level and turns on the transistor 35. This allows the battery pack 1F to supply sufficient power to the coil of the relay 24, allowing the storage battery 11 to be stably discharged without being affected by individual differences in the relay 24.

[0115] 11 shows an example of the configuration of another battery pack 1G according to this modification. The battery pack 1G includes a protection circuit 20G. The protection circuit 20G includes a relay 22, a switch control circuit 30G, a transistor 26, and a resistance element 25. The switch control circuit 30G includes diodes D21 to D24, resistance elements 31 and 32, a control circuit 33, an SR latch 36, and a resistance element 37. In this protection circuit 20G, the resistance element 34, transistor 35, and relay 24 in the battery pack 1F (FIG. 10) are replaced with the SR latch 36, resistance element 37, and transistor 26.

[0116] The set terminal of the SR latch 36 is connected to the terminal OUT of the control circuit 33, the reset terminal is connected to the terminal BATT of the battery pack 1G, and the output terminal is connected to the gate of the transistor 26.

[0117] One end of the resistor element 37 is connected to the output terminal of the SR latch 36, and the other end is connected to the negative terminal BN of the battery pack 1G.

[0118] The transistor 26 is an N-type field effect transistor, with its drain connected to the other end of the resistance element 25, its gate connected to the output terminal of the SR latch 36, and its source connected to the negative terminal BN of the battery pack 1G.

[0119] Here, the switch control circuit 30G corresponds to a specific but not limiting example of "switch control circuit" in an embodiment of the present disclosure. The transistor 26 corresponds to a specific but not limiting example of "first switch" in an embodiment of the present disclosure.

[0120] In this battery pack 1G, when the voltage at terminal OUT becomes high, the SR latch 36 is set, and the output voltage of the SR latch 36 becomes high. This turns on the transistor 26, causing the storage battery 11 to discharge. Even if the power generated by the six Peltier elements 13 becomes smaller, the output voltage of the SR latch 36 remains high, so the transistor 26 remains on. This allows the storage battery 11 to be sufficiently discharged.

[0121] In this way, in the battery pack 1G, the voltage of the control terminal of the first switch (transistor 26) can be set to an ON voltage for turning the first switch ON based on the power generated by the thermoelectric conversion element (six Peltier elements 13), and a switch control circuit 30G is provided that can maintain the voltage of the control terminal after the voltage of the control terminal is set to the ON voltage. This allows the storage battery 11 to be discharged stably, similar to the switch control circuit 30F. Furthermore, the transistor 26 can be used instead of the relay 24, which is a latching relay.

[0122] [Variation 6] In the above embodiment, the charger 100 controls the temperature of the storage battery 11 when charging the battery pack 1. However, this is not limiting. Alternatively, for example, as in a charger 100H shown in FIG. 12, the temperature of the storage battery 11 may not be controlled when charging the battery pack 1. This charger 100H includes a charging circuit 101. This charger 100H is the same as the charger 100 (FIG. 1) according to the above embodiment, except that the temperature control circuit 102 is omitted. When this charger 100H is connected to the battery pack 1, nothing is connected to the drive terminal POWP, and therefore almost no current flows through the coil of the relay 22. Therefore, the relay 22 connects the terminal T1 to the terminal T3. As a result, the positive terminal of the Peltier element 13F is connected to the control terminal C2 of the relay 24 via the relay 22 and the resistive element 23. That is, in this case, in the battery pack 1, while the storage battery 11 is being charged, the power generated by the six Peltier elements 13 is supplied to the coil of the relay 24. Then, when the power generated by the six Peltier elements 13 is large enough to operate the relay 24, the relay 24 connects the terminal T1 to the terminal T2, and the storage battery 11 is discharged.

[0123] [Variation 7] In the above embodiment, the battery pack 1 is configured to be capable of controlling the temperature of the storage battery 11, but this is not limiting. Alternatively, for example, the battery pack 1 may not control the temperature of the storage battery 11, as in the battery pack 1H shown in FIG. 13 . This battery pack 1H includes a protection circuit 20H. The protection circuit 20H is configured to discharge the storage battery 11 when there is a large temperature difference between the outside air temperature and the temperature of the storage battery 11, regardless of whether the battery pack 1 is connected to a charger 100H. The protection circuit 20H includes a resistive element 23, a relay 24, and a resistive element 25. This protection circuit 20H is similar to the protection circuit 20 ( FIG. 1 ) according to the above embodiment, except that the resistive element 21 and the relay 22 are omitted and one end of the resistive element 23 is connected to the positive terminal of the Peltier element 13F.

[0124] In this example, six Peltier elements 13 are provided, but this is not limited to this. Instead, six thermocouples 43 (thermocouples 43A to 43F) may be provided, as in the battery pack 1J shown in FIG. 14.

[0125] [Variation 8] In the above embodiment, the heat sink 14 is provided, but this is not limiting and the heat sink 14 may not be provided. In this case, the Peltier element 13 is thermally connected to the housing 90 of the battery pack 1. Specifically, the Peltier element 13 may be thermally connected to the housing 90 by, for example, direct contact with the housing 90, or may be thermally connected to the housing 90 via a thermally conductive connecting member. In this example, the housing 90 is made of a thermally conductive material. The housing 90 is thermally connected to the outside air. Therefore, the Peltier element 13 can generate power according to the temperature difference between the temperature of the outside air and the temperature of the storage battery 11.

[0126] [Other variations] Two or more of these variations may also be combined.

[0127] Although the present technology has been described above by giving embodiments, the present technology is not limited to these embodiments and can be modified in various ways.

[0128] For example, in the above-described embodiment, the relays 22 and 24 are used, but the present invention is not limited to this, and instead, for example, a semiconductor switch element may be used.

[0129] For example, in the above-described embodiments, cylindrical battery cells 12 are used. The cylindrical battery cells 12 may be, for example, a cylindrical can type, a cylindrical laminate type, or a cylindrical resin type. Alternatively, for example, a prismatic battery cell 12 may be used. The prismatic battery cells 12 may be, for example, a prismatic can type, a prismatic laminate type, or a prismatic resin type. Alternatively, for example, a coin-shaped battery cell 12 may be used.

[0130] The effects described in this specification are merely examples, and the effects of the present disclosure are not limited to the effects described in this specification. Therefore, other effects may be obtained with respect to the present disclosure.

[0131] Furthermore, the present disclosure may take the following aspects. <1> a storage battery having a positive electrode and a negative electrode and capable of storing electric power; a thermoelectric conversion element thermally connected to the storage battery and capable of generating electric power through thermoelectric conversion; a first switch that is provided in a path connecting the positive electrode and the negative electrode, has a control terminal to which the power generated by the thermoelectric conversion element is applied, and is turned on based on the power generated by the thermoelectric conversion element, thereby being able to discharge the storage battery; A battery pack equipped with <2> further comprising a heat sink thermally connected to the ambient air; The thermoelectric conversion element is further thermally connected to the heat sink and is capable of generating electric power according to the difference between the temperature of the outside air and the temperature of the storage battery. <1> The battery pack described. <3> a housing that houses the storage battery, the thermoelectric conversion element, and the first switch and is thermally connected to the outside air; The thermoelectric conversion element is further thermally connected to the housing and is capable of generating power according to the difference between the temperature of the outside air and the temperature of the storage battery. <1> The battery pack described. <4> The first switch is capable of maintaining an on state after being turned on based on the power generated by the thermoelectric conversion element. <1> from <3> 10. The battery pack according to claim 9, wherein: <5> The thermoelectric conversion element further includes a switch control circuit that drives the control terminal of the first switch based on the power generated by the thermoelectric conversion element, thereby turning on the first switch. <4> The battery pack described. <6> The device further includes a switch control circuit that can set the voltage of the control terminal of the first switch to an on-voltage for turning on the first switch based on the power generated by the thermoelectric conversion element, and that can maintain the voltage of the control terminal after setting the voltage of the control terminal to the on-voltage. <1> from <3> 10. The battery pack according to claim 9, wherein: <7> further comprising a first diode, a second diode, a third diode, and a fourth diode; the thermoelectric conversion element has a first terminal and a second terminal, the control terminal of the first switch includes a first control terminal and a second control terminal; the first diode has an anode connected to the first terminal of the thermoelectric conversion element and a cathode connected to the first control terminal of the first switch; the second diode has an anode connected to the second terminal of the thermoelectric conversion element and a cathode connected to the first control terminal of the first switch, the third diode has an anode connected to the second control terminal of the first switch and a cathode connected to the second terminal of the thermoelectric conversion element, The fourth diode has an anode connected to the second control terminal of the first switch and a cathode connected to the first terminal of the thermoelectric conversion element. <1> from <3> 10. The battery pack according to claim 9, wherein: <8> a drive terminal to which drive power can be supplied; The second switch and Furthermore, the thermoelectric conversion element includes a Peltier element, the second switch is capable of supplying the driving power to the thermoelectric conversion element; The first switch is capable of discharging the storage battery when the second switch is not supplying the driving power to the thermoelectric conversion element. <1> from <7> 10. The battery pack according to claim 9, wherein: <9> the thermoelectric conversion element has a first terminal and a second terminal, The driving power can be selectively set to a power of a first polarity in which the voltage of the first terminal is higher than the voltage of the second terminal, or to a power of a second polarity in which the voltage of the first terminal is lower than the voltage of the second terminal. <8> The battery pack described. <10> The second switch is a first terminal connected to the thermoelectric conversion element, a second terminal connected to the drive terminal, a third terminal connected to the control terminal of the first switch, and a control terminal connected to the drive terminal; When the driving power is supplied to the driving terminal, the first terminal and the second terminal can be connected to each other; When the driving power is not supplied to the driving terminal, the first terminal and the third terminal are connectable to each other. <8> or <9> The battery pack described. <11> a resistor element having one end connected to the drive terminal and the other end connected to the control terminal of the second switch; The second switch is operable based on a current flowing through the control terminal. <10> The battery pack described. <12> further comprising a fifth diode, a sixth diode, a seventh diode, and an eighth diode; the drive terminals include a first drive terminal and a second drive terminal; the control terminal of the second switch includes a first control terminal and a second control terminal; the fifth diode has an anode connected to the first drive terminal and a cathode connected to the first control terminal of the second switch; the sixth diode has an anode connected to the first drive terminal and a cathode connected to the second control terminal of the second switch; the seventh diode has an anode connected to the second control terminal and a cathode connected to the second drive terminal; The eighth diode has an anode connected to the first control terminal and a cathode connected to the second drive terminal. have <10> or <11> The battery pack according to claim 1. <13> further comprising a control signal terminal to which a control signal can be supplied; The second switch is a first terminal connected to the thermoelectric conversion element, a second terminal connected to the drive terminal, a third terminal connected to the control terminal of the first switch, and a control terminal connected to the control signal terminal; When the control signal is supplied to the control signal terminal, the first terminal and the second terminal can be connected to each other; When the control signal is not supplied to the control signal terminal, the first terminal and the third terminal are connectable to each other. <8> or <9> The battery pack described. <14> The battery pack further includes a monitoring circuit that can monitor the operating state of the battery pack when the battery pack is connected to a device and can operate in a sleep state when the battery pack is not connected to a device. <1> from <13> 10. The battery pack according to claim 9, wherein: [Explanation of symbols]

[0132] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1J... battery pack, 2... resistor element, 11... storage battery, 12... battery cell, 13, 13A, 13B, 13C, 13D, 13E, 13F... Peltier element, 14... heat sink, 15... temperature sensor, 16... monitoring circuit, 19... cell holder, 20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H... protection circuit, 21... resistor element, 22, 22D... relay, 23... resistor element, 24, 24D... relay, 25... resistor element, 26... transistor, 30F, 30G... switch control circuit, 31... resistor element, 32... resistor element, 33... control circuit, 34... resistor element, 35... transistor, 36... SR line switch, 37...resistance element, 43, 43A, 43B, 43C, 43D, 43E, 43F...thermocouple, 90...housing, 100, 100A, 100B, 100C, 100E, 100H...charger, 101, 101E...charging circuit, 102, 102A, 102B, 102C...temperature control circuit, BATT...terminal, BN...negative terminal, BP...positive terminal, C1, C2...control terminal, D1, D2, D3, D4, D11, D12, D13, D14, D21, D22, D23, D24...diode, EN...negative electrode, EP...positive electrode, G...group, GA, GB, GC, GD, GE, GF...group, POWN, POWP...drive terminal, S1...surface, S2...surface, T1...terminal, T2...terminal, T3...terminal.

Claims

1. a storage battery having a positive electrode and a negative electrode and capable of storing electric power; a thermoelectric conversion element thermally connected to the storage battery and capable of generating electric power through thermoelectric conversion; a first switch that is provided in a path connecting the positive electrode and the negative electrode, has a control terminal to which the power generated by the thermoelectric conversion element is applied, and is turned on based on the power generated by the thermoelectric conversion element, thereby being able to discharge the storage battery; A battery pack equipped with

2. further comprising a heat sink thermally connected to the ambient air; The thermoelectric conversion element is further thermally connected to the heat sink and is capable of generating electric power according to the difference between the temperature of the outside air and the temperature of the storage battery. The battery pack according to claim 1 .

3. a housing that houses the storage battery, the thermoelectric conversion element, and the first switch and is thermally connected to the outside air; The thermoelectric conversion element is further thermally connected to the housing and is capable of generating power according to the difference between the temperature of the outside air and the temperature of the storage battery. The battery pack according to claim 1 .

4. The first switch is capable of maintaining an on state after being turned on based on the power generated by the thermoelectric conversion element. The battery pack according to claim 1 .

5. The thermoelectric conversion element further includes a switch control circuit that drives the control terminal of the first switch based on the power generated by the thermoelectric conversion element, thereby turning on the first switch. The battery pack according to claim 4.

6. The power supply further includes a switch control circuit that can set the voltage of the control terminal of the first switch to an ON voltage for turning on the first switch based on the power generated by the thermoelectric conversion element, and that can maintain the voltage of the control terminal after the voltage of the control terminal is set to the ON voltage. The battery pack according to claim 1 .

7. further comprising a first diode, a second diode, a third diode, and a fourth diode; the thermoelectric conversion element has a first terminal and a second terminal; the control terminal of the first switch includes a first control terminal and a second control terminal; the first diode has an anode connected to the first terminal of the thermoelectric conversion element and a cathode connected to the first control terminal of the first switch; the second diode has an anode connected to the second terminal of the thermoelectric conversion element and a cathode connected to the first control terminal of the first switch, the third diode has an anode connected to the second control terminal of the first switch and a cathode connected to the second terminal of the thermoelectric conversion element; The fourth diode has an anode connected to the second control terminal of the first switch and a cathode connected to the first terminal of the thermoelectric conversion element. The battery pack according to claim 1 .

8. a drive terminal to which drive power can be supplied; A second switch and Furthermore, the thermoelectric conversion element includes a Peltier element, the second switch is capable of supplying the driving power to the thermoelectric conversion element; The first switch is capable of discharging the storage battery when the second switch is not supplying the driving power to the thermoelectric conversion element. The battery pack according to any one of claims 1 to 7.

9. the thermoelectric conversion element has a first terminal and a second terminal; The driving power can be selectively set to a power of a first polarity in which the voltage of the first terminal is higher than the voltage of the second terminal, or to a power of a second polarity in which the voltage of the first terminal is lower than the voltage of the second terminal. The battery pack according to claim 8.

10. The second switch is a first terminal connected to the thermoelectric conversion element, a second terminal connected to the drive terminal, a third terminal connected to the control terminal of the first switch, and a control terminal connected to the drive terminal; When the driving power is supplied to the driving terminal, the first terminal and the second terminal are connectable to each other; When the driving power is not supplied to the driving terminal, the first terminal and the third terminal are connectable to each other. The battery pack according to claim 8.

11. a resistor element having one end connected to the drive terminal and the other end connected to the control terminal of the second switch; The second switch is operable based on a current flowing through the control terminal. The battery pack according to claim 10.

12. further comprising a fifth diode, a sixth diode, a seventh diode, and an eighth diode; the drive terminals include a first drive terminal and a second drive terminal; the control terminal of the second switch includes a first control terminal and a second control terminal; the fifth diode has an anode connected to the first drive terminal and a cathode connected to the first control terminal of the second switch; the sixth diode has an anode connected to the first drive terminal and a cathode connected to the second control terminal of the second switch; the seventh diode has an anode connected to the second control terminal and a cathode connected to the second drive terminal; The eighth diode has an anode connected to the first control terminal and a cathode connected to the second drive terminal. have The battery pack according to claim 10.

13. further comprising a control signal terminal to which a control signal can be supplied; The second switch is a first terminal connected to the thermoelectric conversion element, a second terminal connected to the drive terminal, a third terminal connected to the control terminal of the first switch, and a control terminal connected to the control signal terminal; When the control signal is supplied to the control signal terminal, the first terminal and the second terminal are connectable to each other; When the control signal is not supplied to the control signal terminal, the first terminal and the third terminal are connectable to each other. The battery pack according to claim 8.

14. The battery pack further includes a monitoring circuit that can monitor the operating state of the battery pack when the battery pack is connected to a device and can operate in a sleep state when the battery pack is not connected to a device. The battery pack according to claim 1 .

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