Hot spot detection in electrical installations

Abstract

An electrical device includes a surface that is exposable to heat generated by operation of the electrical device, causing the temperature of the surface to increase during operation. The surface includes a temperature sensor comprising first and second electrodes separated by a layer of control material, wherein the material properties and / or configuration of the control material are selected such that the electrical conductivity of the control material increases with increasing temperature, thereby enabling current to flow between the first and second electrodes once the temperature of any portion of the control material reaches or exceeds a predetermined temperature. The temperature sensor extends over substantially the entire surface. Also disclosed are systems including the electrical device and methods of controlling the electrical device.

Description

Technical Field

[0001] The present disclosure relates to hot spot detection in electrical devices. Specifically, the present disclosure relates to hot spot detection anywhere on the surface of an electrical device. The present disclosure also relates to systems and methods for controlling an electrical device based on the detection of a hot spot. Background Art

[0002] It's well known that electrical devices generate heat during operation. Examples of such devices include motors, fans, pumps, generators, heaters, and batteries. During normal operation, a certain amount of heat generation is expected. However, if an electrical device malfunctions or operates for extended periods, the heat generated can become excessive.

[0003] For consumer electronic devices such as home care or personal care appliances, the heat generated could cause harm to the user if the external surface of the device becomes too hot to touch and could burn. In all cases, excessive heat generation can cause damage to the device and, in extreme cases, fire.

[0004] Rechargeable, or secondary, batteries are particularly sensitive to high temperatures, as their lifespan is shortened by high-temperature operation. Furthermore, secondary batteries are at risk of thermal runaway in the event of damage, short circuiting, or overcharging. Thermal runaway, particularly in modern lithium-ion secondary batteries, can lead to fires and explosions if not managed properly.

[0005] It is in this context that the present invention is designed. Summary of the Invention

[0006] The present invention provides an electrical device comprising a surface including a temperature sensor extending over substantially the entire surface, the temperature sensor comprising first and second electrodes separated by a layer of control material, wherein the material properties and / or configuration of the control material are such that the electrical conductivity of the control material increases with increasing temperature, such that, in use, current can pass between the first and second electrodes once the temperature of any part of the control material reaches or exceeds a predetermined temperature, wherein the temperature sensor extends over substantially the entire surface.

[0007] Advantageously, hot spots occurring on any portion of a surface comprising a temperature sensor can be detected. For example, the surface may be exposed to heat originating from the operation of an electrical device, such that the temperature of the surface may increase during operation of the electrical device.

[0008] Optionally, the temperature sensor includes an additional electrode separated from the second electrode by an additional control material layer, wherein the material properties and / or configuration of the additional control material layer are selected such that the conductivity of the control material increases with increasing temperature, such that once the temperature of any portion of the additional control material layer reaches or exceeds a second predetermined temperature, current can pass between the additional electrode and the second electrode. Thus, a first or warning temperature occurring on a surface including the temperature sensor can be detected before the surface reaches a more critical second temperature.

[0009] The surface may optionally include a second temperature sensor comprising third and fourth electrodes separated by a second control material layer, wherein the material properties and / or configuration of the second control material layer are selected such that the conductivity of the control material increases with increasing temperature, such that current can flow between the third and fourth electrodes once the temperature of any portion of the second control material layer reaches or exceeds a second predetermined temperature. Similarly, with this configuration, a first or warning temperature occurring on the surface including the temperature sensor can be detected before the surface reaches a more critical second temperature.

[0010] The second temperature sensor optionally extends over substantially the entire surface to obtain maximum detector coverage.

[0011] The or each control material may be selected from the group consisting of a thermistor material, a thermoelectric material, a phase change material or a metal-insulator transition (MIT) material.

[0012] Optionally, the or each temperature sensor may be covered by a protective layer or contained within a protective cover.

[0013] The electrical device may include a battery, a motor, or a heater.

[0014] The electrical device may include a battery cell that may include an electrode assembly including an anode current collector and a cathode current collector located on either side of a separator material.

[0015] Alternatively, a first battery cell and a second battery cell may be provided, wherein the or each temperature sensor is sandwiched between the first and second battery cells to provide hot spot detection between the battery cells.

[0016] The or each temperature sensor may optionally have substantially the same footprint as the anode current collector and / or cathode current collector to ensure hot spot detection at these areas.

[0017] Optionally, the electrode assembly has the form of a jelly roll and wherein the or each temperature sensor is located substantially in the middle of the jelly roll electrode assembly to allow hot spot detection in the middle of the jelly roll.

[0018] The or each battery cell may be located within a housing.

[0019] The surface may optionally comprise at least a portion of an outer casing of the electrical device, and the or each temperature sensor may be located on an inner or outer surface of the outer casing.Alternatively or additionally, the temperature sensor may be embedded within the material of the outer casing.

[0020] In another aspect, the present invention provides a system comprising an electrical device as described above and a hotspot detector, the hotspot detector comprising a processor configured to receive an input signal, wherein the input signal indicates current flow in a sensor circuit connected to an electrode of a temperature sensor of the electrical device, wherein the processor is configured to output a control signal based on the indicated presence of current flow in the sensor circuit.

[0021] Optionally, the processor may be configured to receive a second input signal, wherein the second input signal indicates a current flow in a second sensor circuit connected to an electrode of a second temperature sensor of the electrical device, wherein the processor is configured to output a second control signal based on the indicated presence of current flow in the second sensor circuit.

[0022] The system may optionally include a controller configured to modify the flow of primary current to and / or from the electrical device upon outputting a control signal from the processor.

[0023] The system may include a battery management system, wherein the electrical device includes a battery, and wherein the primary current flow is current drawn from the battery or current provided to the battery for charging the battery.

[0024] In another aspect, the present invention provides a method of controlling an electrical device as described above, the method comprising: sensing current flow in a sensor circuit connected to an electrode of a temperature sensor of the electrical device; issuing a control signal to a controller when current flow in the sensor circuit is sensed; and upon receiving the control signal, using the controller to modify the main current flow to and / or from the electrical device.

[0025] Optionally, the method may include sensing a second current flow in a second sensor circuit connected to an electrode of a second temperature sensor of the electrical device; issuing a second control signal to a controller when the second current flow is sensed; and using the controller to further modify the main current flow to and / or from the electrical device upon receipt of the second control signal.

[0026] When the first control signal is received, a first main current control protocol may be initiated, and when the second control signal is received, a second main current control protocol may be initiated.

[0027] Optionally, the second main current control protocol may include substantially stopping main current flow to and / or from the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention will now be described by way of non-limiting examples with reference to the following accompanying drawings, in which:

[0029] Figure 1 A schematic diagram of a system including an electrical device, a processor, and a controller is shown;

[0030] Figure 2 shows a schematic diagram of a temperature sensor;

[0031] Figure 3 shows a schematic diagram of another temperature sensor;

[0032] Figure 4 shows a schematic diagram of another system including an electrical device, a processor, and a controller;

[0033] Figure 5 shows a schematic diagram of yet another temperature sensor;

[0034] Figure 6 shows a schematic diagram of a battery cell including a temperature sensor;

[0035] Figure 7 shows a schematic diagram of two battery cell stacks including a temperature sensor sandwiched therebetween;

[0036] Figure 8 Shown Figure 6 A schematic diagram of a partially exploded plan view of a battery cell;

[0037] Figure 9 shows a schematic diagram of a temperature sensor located within a jelly roll electrode assembly;

[0038] Figure 10 shows a schematic diagram of another battery cell stack including a temperature sensor; and

[0039] Figures 11a to 11c Schematic diagram showing alternative locations for temperature sensors. DETAILED DESCRIPTION

[0040] Figure 1 A schematic diagram of a system 10 is shown that includes an electrical device 20, a processor 30, and a controller 40. The electrical device 20 can be any electrical device that is capable of generating heat during operation. Examples include motors, fans, pumps, generators, heaters, and batteries.

[0041] The electrical device 20 is connected to a main cable 21, which carries a main current flow when the electrical device 20 is in operation. Depending on the type of electrical device, the main current flow may be a current supply from a power source 23 (e.g., in the case of a motor, heater, or fan) to the electrical device 20, or it may be a current flow from the electrical device to a power consumer 24 (e.g., in the case of a generator or battery). In the specific case of a battery, the main current flow may be a current flow from the battery to another electrical device (e.g., a phone, laptop, or the drive motor of an electric vehicle), or it may be a current flow to the battery for the purpose of charging the battery.

[0042] Substantially the entire outer surface 22 of the electrical device 20 is covered by the temperature sensor 50 as a film. Figure 2 , the temperature sensor 50 includes a first electrode 52 and a second electrode 54 separated by a control material 56. The control material 56 is configured such that the electrical conductivity of the control material increases with increasing temperature, allowing current to flow between the first and second electrodes once the temperature of any portion of the control material reaches or exceeds a predetermined temperature. Thus, the control material acts as an electrical insulator below the predetermined temperature, preventing current from flowing between the first and second electrodes 52, 54. However, if any portion of the outer surface 22 of the electrical device 20 reaches (or exceeds) the predetermined temperature, the material properties of the control material 56 change, allowing current to flow between the first and second electrodes 52, 54. Thus, the temperature sensor 50 can detect the presence of a hot spot on any portion of the outer surface 22 of the electrical device 20.

[0043] Suitable materials for control material 56 include thermistor materials (e.g., iron oxide, nickel oxide, barium titanate, or polymers), thermoelectric materials (e.g., bismuth chalcogenide and lead telluride), phase change materials (e.g., waxes, lipids, and salt hydrides), and metal-insulator transition (MIT) materials (e.g., vanadium dioxide, silicon dioxide, and titanium dioxide).

[0044] A suitable MIT material is vanadium dioxide (VO2), which can be fine-tuned by adding dopants such as hydrogen, iron, cobalt, nickel, molybdenum, niobium, hafnium, magnesium, germanium, sodium, potassium, titanium, silicon, and tungsten to change its behavior from an electrical insulator below a predetermined temperature to an electrical conductor above a predetermined temperature. For example, a control material 56 made of VO2 can be tuned to change its behavior from an insulator to a conductor at 80°C, 90°C, or 100°C. It should be understood that these are merely example temperatures, and that the control material 56 can be tuned to change its conductive properties at any suitable temperature within the range allowed by the particular control material 56.

[0045] Reference again Figure 1, the first and second electrodes 52, 54 of the temperature sensor 50 are connected to the sensor circuit 12 having the sensor power supply 14. Under normal operating conditions, when the temperature of the outer surface 22 of the electrical device 20 is below a predetermined temperature, no current flows in the sensor circuit 12 because current cannot pass between the first and second electrodes 52, 54 through the control material 56. However, if any portion of the outer surface 22 reaches or exceeds the predetermined temperature, resulting in a hot spot, the conductivity of the control material 56 in the hot spot area increases, so that current can flow between the first and second electrodes 52, 54. Of course, if the entire or a majority of the outer surface 22 reaches or exceeds the predetermined temperature, current will be able to flow between the first and second electrodes 52, 54.

[0046] The processor 30 has an input 31 which is arranged to have a zero value when no current is flowing in the sensor circuit 12 and a non-zero value when current is flowing in the sensor circuit 12. Thus, the input 31 of the processor 30 represents the current flowing in the sensor circuit 12.

[0047] Processor 30 is configured to output control signal 32 when a non-zero value indicative of current flow in sensor circuit 12 is input to input 31. Control signal 32 is received by controller 40 which is configured to modify the main current flow in main cable 21 .

[0048] In the event that the main cable 21 provides power from the power source 23 to the electrical device 20, the controller 40 can be configured to stop or reduce the flow of the main current to permanently shut down operation of the electrical device 20, or until the electrical device 20 has cooled sufficiently to allow normal operation to resume. Alternatively, (or in addition to in the case of a battery), in the event that the main cable 21 provides power from the electrical device 20 to the power consumer 24, the controller 40 can be configured to permanently stop or reduce the flow of the main current, or until the electrical device 20 has cooled sufficiently to allow normal operation to resume.

[0049] Figure 3Another example of a temperature sensor 51 is shown. For clarity, the same reference numerals are used throughout this specification to represent the same components. The temperature sensor 51 includes two temperature sensors 50a, 50b, one located on top of the other and separated by an electrically insulating layer 59. The first temperature sensor 50a includes a first electrode 52a and a second electrode 54a separated by a first control material 56a. The second temperature sensor 50b includes a third electrode 52b and a fourth electrode 54b separated by a second control material 56b. The first control material 56a is configured to change from an electrical insulator to an electrical conductor at a first predetermined temperature, and the second control material 56b is configured to change from an electrical insulator to an electrical conductor at a second predetermined temperature that is higher than the first predetermined temperature. In this way, the temperature sensor 51 is capable of detecting when any portion of the outer surface 22 of the electrical device 20 reaches the first predetermined temperature, as well as when the same (or any other) portion of the outer surface 22 reaches the second predetermined temperature.

[0050] The first and second electrodes 52a, 54a of the first temperature sensor 50a are connected to the first sensor circuit 12a connected to the sensor power supply 14, and the third and fourth electrodes 52b, 54b of the second temperature sensor 50b are connected to the second sensor circuit 12b connected to the sensor power supply 14.

[0051] Now refer to Figure 4 Under normal operating conditions, when the temperature of the outer surface 22 of the electrical device 20 is below a first predetermined temperature, no current flows in the sensor circuits 12a, 12b because current cannot pass between the first and second electrodes 52a, 54a through the first control material 56a, or between the third and fourth electrodes 52b, 54b through the second control material 56b. However, if any portion of the outer surface 22 reaches or exceeds the first predetermined temperature, resulting in a hot spot, the conductivity of the first control material 56a in the hot spot region increases, allowing current to flow between the first and second electrodes 52a, 54a. This causes current to flow in the first sensor circuit 12a.

[0052] Similarly, if any portion of the outer surface 22 reaches or exceeds the second predetermined temperature, the conductivity of the second control material 56b in the hotspot region increases, so current can flow between the third and fourth electrodes 52b, 54b. This causes current to flow in the second sensor circuit 12b.

[0053] Processor 30 is configured to receive two inputs. First input 31a is configured to have a value of zero when no current is flowing in first sensor circuit 12a, and a non-zero value when current is flowing in first sensor circuit 12a. Therefore, first input 31a of processor 30 indicates current flowing in first sensor circuit 12a. Similarly, second input 31b is configured to have a value of zero when no current is flowing in second sensor circuit 12b, and a non-zero value when current is flowing in second sensor circuit 12b. Therefore, second input 31b indicates current flowing in second sensor circuit 12b.

[0054] Processor 30 is configured to output two control signals. Upon receiving a non-zero value first input 31a indicating current flow in first sensor circuit 12a, a first control signal 32a is issued, and upon receiving a non-zero value second input 31b indicating current flow in second sensor circuit 12b, a second control signal 32b is issued. Output signals 32a, 32b are received by controller 40, which is configured to modify the flow of the main current in main cable 21 based on the output signals 32a, 32b received from processor 30.

[0055] The controller 40 can be configured to reduce the flow of the main current upon receiving the first control signal 32a, and to stop the flow of the main current upon receiving the second control signal 32b. Alternatively or in addition, the controller 40 can be configured to issue an alarm signal upon receiving the first control signal 32a to indicate to a user or an automated control system that a first predetermined temperature has been reached somewhere on the outer surface 22 of the electrical device 20. This then allows the user or control system to intervene or perform diagnostic tests before the second predetermined temperature is reached.

[0056] Figure 5 A third example of a temperature sensor 53 is shown comprising a first electrode 52c and a second electrode 54c separated by a first control material 56c. An additional electrode 55 is located adjacent the second electrode 54c and separated from the second electrode 54c by a layer of additional control material. Figure 5 The temperature sensor 53 is connected to Figure 3 The temperature sensor 51 operates in a very similar manner, in that the two control material layers 56c, 57 are configured to change from an electrical insulator to an electrical conductor at two different predetermined temperatures. In the case of the temperature sensor 53, if a first predetermined temperature is reached, current is enabled to flow in the first sensor circuit 12a, such that current can flow between the first and second electrodes 52c, 54c through the first control material 56c, and if a second predetermined temperature is reached, current is enabled to flow in the second sensor circuit 12b, such that current can flow between the second and additional electrodes 54c, 55 through the second control material layer 57. The processor 30 and the controller 40 then proceed in the same manner as described above with reference to FIG. Figure 4 The system 10 is controlled in the same manner.

[0057] Figure 6 A battery cell is shown comprising an anode 61 and a cathode 63 separated by a separator layer 62. The electrolyte is contained within the separator layer 62. A temperature sensor 50 is located next to the cathode 63, and a protective material layer 70, such as polypropylene or polyethylene terephthalate (PET), is located next to the temperature sensor 50. It should be understood that the temperature sensor may correspond to any of the temperature sensors 50, 51, 53 described above, and that the temperature sensors 50, 51, 53 may be located next to the anode 61 instead of, or in addition to, the cathode 63. In the event that the temperature sensors 50, 51, 53 are located on both sides of the battery cell 60, one or both may be covered by the protective material layer 70. Alternatively, the entire battery cell 60, including the or each temperature sensor 50, 51, 53, may be located within a protective material bag.

[0058] Figure 7 An alternative battery arrangement 65 is shown that includes first and second battery cells 60a, 60b arranged in a stack. The first battery cell 60a includes a first anode 61a and a first cathode 63a separated by a first separator layer 62a. The second battery cell 60b includes a second anode 61b and a second cathode 63b separated by a first separator layer 62b. A temperature sensor 50 is sandwiched between the first and second battery cells 60a, 60b. The temperature sensor 50 is contained within a protective material bag 70a, such as a polypropylene bag. Alternatively, one or both sides of the temperature sensor 50 may be covered by a protective material layer, or the protective material layer may not be included at all. It should be understood that the temperature sensor may correspond to any of the temperature sensors 50, 51, 53 described above.

[0059] Despite Figure 7 Only two battery cells 60 a , 60 b are shown, but it will be appreciated that the battery 65 may include a plurality of battery cells 60 arranged in a stack, with the temperature sensors 50 , 51 , 53 located between some or all of the battery cells 60 .

[0060] Figure 8 Shown Figure 6 Schematic partially exploded plan view of a battery cell 60. It can be seen here that the footprint of the temperature sensors 50, 51, 53 is substantially the same as the footprint of the anode 61 and cathode 63. This allows the temperature sensors 50, 51, 53 to sense hot spots that occur in any part of the battery cell 60. Figure 7 The temperature sensors 50, 51, 53 also have the same arrangement, so that the temperature sensors 50, 51, 53 can sense hot spots that appear in any part of the battery cells 60a, 60b. Figure 7 between the battery cells 60a, 60b, it is possible to detect hot spots in the middle of the battery 65 as well as on the outer surfaces where additional temperature sensors 50, 51, 53 may be located.

[0061] Figure 9 Another alternative battery cell arrangement 66 is shown. Figure 9 The battery cell includes a "jelly roll" type electrode assembly 67, which includes an anode and a cathode located on either side of a separator and rolled into a substantially flat spiral. The battery cell 66 includes a temperature sensor 50, 51, 53 located substantially in the center of the jelly roll electrode assembly 67 for sensing hot spots within the jelly roll electrode assembly 67. One or more temperature sensors 50, 51, 53 may also be located on an outer surface of the jelly roll electrode assembly 67. The temperature sensors 50, 51, 53 may include a protective material layer 70 or may be located within a protective material bag.

[0062] Figure 10 An alternative battery 68 is shown that includes two jellyroll battery cells 66a, 66b positioned in a stack. The first jellyroll battery cell 66a includes a first jellyroll electrode assembly 67a, and the second jellyroll battery cell 66b includes a second jellyroll electrode assembly 67b. A temperature sensor 50 is sandwiched between the first and second jellyroll battery cells 66a, 66b. The temperature sensor 50 can be contained within a protective material pouch. Alternatively, one or both sides of the temperature sensor 50 can be covered by a protective material layer, or no protective material layer can be included at all. It should be understood that the temperature sensor can correspond to any of the temperature sensors 50, 51, 53 described above. Furthermore, depending on design choice, the jellyroll battery cells 66a, 66b can include or not include the temperature sensor 50, 51, 53 located at their center.

[0063] Despite Figure 9 Only two jelly roll battery cells 66a, 66b are shown, but it should be understood that the battery 68 may include a plurality of jelly roll battery cells 66 arranged in a stack with the temperature sensors 50, 51, 53 located between some or all of the jelly roll battery cells 66.

[0064] Figures 11a to 11c A schematic diagram of a section through an outer shell 80a, 80b, 80c is shown, which may form an outer housing of an electrical device 20 according to any of the above-described embodiments. The outer shell 80a, 80b, 80c may be made of a rigid or flexible material.

[0065] like Figure 11aAs shown, the outer shell 80a has a temperature sensor 50 located on the outer surface of the outer shell 80a. Substantially the entire outer surface of the outer shell 80a can be covered by a single temperature sensor 50. Alternatively, multiple temperature sensors 50 can be used to cover the outer surface of the outer shell 80a. In another alternative, only a portion of the outer surface of the outer shell 80a can be covered by one or more temperature sensors 50.

[0066] Figure 11b An outer shell 80b is shown having a temperature sensor 50 located on the inner surface of the outer shell 80b. Substantially the entire inner surface of the outer shell 80b may be covered by a single temperature sensor 50. Alternatively, multiple temperature sensors 50 may be used to cover the inner surface of the outer shell 80b. In another alternative, only a portion of the inner surface of the outer shell 80b may be covered by one or more temperature sensors 50.

[0067] Figure 11c Housing 80c is shown having a temperature sensor 50 embedded in the material of housing 80c. Substantially the entire housing 80c may have a single temperature sensor 50 embedded therein. Alternatively, multiple temperature sensors 50 may be embedded within housing 80c. In another alternative, only a portion of housing 80c may include one or more embedded temperature sensors 50. It should be understood that the temperature sensors of housings 80a, 80b, 80c may correspond to any of the temperature sensors 50, 51, 53 described above.

Claims

1. An electrical device comprising a surface, the surface comprising: a first temperature sensor extending across the entire surface, the first temperature sensor comprising first and second electrodes separated by a layer of control material, wherein the material properties and / or configuration of the control material are such that the electrical conductivity of the control material increases with increasing temperature, whereby, in use, current is able to pass between the first and second electrodes once the temperature of any part of the control material reaches or exceeds a predetermined temperature, a second temperature sensor comprising third and fourth electrodes separated by a second control material layer, wherein the material properties and / or configuration of the second control material layer are selected such that the conductivity of the control material increases with increasing temperature, thereby enabling current to pass between the third and fourth electrodes once the temperature of any portion of the second control material layer reaches or exceeds a second predetermined temperature, The first temperature sensor and the second temperature sensor are separated by an electrical insulation layer.

2. The electrical device according to claim 1, wherein The first temperature sensor comprises an additional electrode separated from the second electrode by an additional control material layer, wherein the material properties and / or configuration of the additional control material layer are selected such that the electrical conductivity of the control material increases with increasing temperature, thereby enabling current to pass between the additional electrode and the second electrode once the temperature of any part of the additional control material layer reaches or exceeds a second predetermined temperature.

3. The electrical device according to claim 1, wherein The second temperature sensor extends over the entire surface.

4. The electrical device according to claim 1, wherein Each of the control materials is selected from the group consisting of a thermistor material, a thermoelectric material, a phase change material, or a metal-insulator transition material.

5. The electrical device according to claim 1, wherein Each of the temperature sensors is covered by a protective layer or contained within a protective cover.

6. The electrical device according to claim 1, wherein The electrical device includes a battery, a motor or a heater.

7. The electrical device according to claim 1, wherein The electrical device includes a battery unit.

8. The electrical device according to claim 7, wherein: The battery cell includes an electrode assembly comprising an anode current collector and a cathode current collector positioned on either side of a separator material.

9. The electrical device of claim 7, comprising a first battery unit and a second battery unit, wherein: Each of the temperature sensors is sandwiched between a first battery cell and a second battery cell.

10. The electrical device according to claim 8, wherein Each of the temperature sensors has the same footprint as the anode current collector and / or cathode current collector.

11. The electrical device according to claim 8, wherein The electrode assembly has a jelly roll form, and wherein each of the temperature sensors is located in the middle of the jelly roll electrode assembly.

12. The electrical device according to claim 7, wherein Each of the battery cells is located in the housing.

13. The electrical device according to claim 1, wherein The surface comprises at least a portion of an outer housing of the electrical device.

14. The electrical device according to claim 13, wherein Each of the temperature sensors is located on the inner surface or the outer surface of the outer shell.

15. The electrical device according to claim 13, wherein The first temperature sensor is embedded in the material of the outer shell.

16. A system comprising an electrical device according to any one of claims 1 to 15 and a hotspot detector, the hotspot detector comprising a processor configured to receive an input signal, wherein: The input signal is indicative of current flow in a sensor circuit connected to an electrode of a temperature sensor of the electrical device, wherein the processor is configured to output a control signal based on the indicated presence of current flow in the sensor circuit.

17. The system of claim 16, wherein: The processor is configured to receive a second input signal, wherein the second input signal indicates a current flow in a second sensor circuit connected to an electrode of a second temperature sensor of the electrical device, wherein the processor is configured to output a second control signal based on the indicated presence of current flow in the second sensor circuit.

18. The system of claim 16, comprising a controller configured to modify the flow of primary current to and / or from the electrical device upon output of a control signal from the processor.

19. The system according to claim 18, wherein: The electrical device comprises a battery, and wherein the main current flow is current drawn from the battery or current supplied to the battery in order to charge the battery.

20. A method for controlling an electrical device according to any one of claims 1 to 15, the method comprising: sensing current flow in a sensor circuit connected to electrodes of a first temperature sensor of the electrical device; When current flowing in the sensor circuit is sensed, a first control signal is sent to the controller; as well as Upon receiving the first control signal, the controller is used to modify the flow of main current to and / or from the electrical device.

21. The method according to claim 20, comprising: sensing a second current flow in a second sensor circuit connected to an electrode of a second temperature sensor of the electrical device; When sensing the flow of the second current, sending a second control signal to the controller; as well as Upon receiving the second control signal, the controller is employed to further modify the main current flow to and / or from the electrical device.

22. The method of claim 21, wherein: A first main current control protocol is initiated upon receipt of the first control signal, and wherein a second main current control protocol is initiated upon receipt of the second control signal.

23. The method of claim 22, wherein: The second main current control protocol includes stopping the flow of main current to and / or from the electrical device.

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