Connector with integrated thermal cutoff for battery packs

Abstract

A temperature-sensitive battery connector is disclosed. The connector may include a connector body and at least one conductor mounted to the connector body and configured to transmit a current signal used to measure the voltage from a battery pack or battery cell to a battery management system (BMS). The connector may include a thermal switch device mounted to the connector body and thermally coupled to a terminal of the battery pack or battery cell. The thermal switch device may be configured to provide an overtemperature signal to the BMS by changing or interrupting the current conducted by the at least one conductor when the temperature of the battery pack or battery cell exceeds a threshold temperature.

Description

[0001] Incorporation by reference into any priority application

[0002] Any and all applications for which foreign or domestic priority claims are identified in the Application Data Sheet filed with the present application are hereby incorporated by reference pursuant to 37 CFR 1.57. Technical Field

[0003] The field relates to integrated thermal cutoff devices for sensing the temperature of a cell or battery pack. Background Art

[0004] In various types of electrical systems, circuit elements or other components, such as batteries (which may include one or more cells), may experience faults that negatively impact the operation or reliability of the larger electrical system. For example, during operation or charging, a battery pack may experience an increase in temperature. If the temperature rises too much, the cell or battery pack, or the larger electrical system, may be damaged by overtemperature and / or overcurrent faults. Such overtemperature faults may reduce the functionality, reliability, lifespan, and / or safety of the device. Therefore, there remains a need for a device that protects a larger electrical system when a circuit element, such as a cell or battery, experiences an overtemperature fault. Summary of the Invention

[0005] In one embodiment, a temperature-sensitive battery connector is disclosed. The temperature-sensitive battery connector may include a connector body and at least one conductor mounted to the connector body and configured to transmit a signal from a battery pack or battery cell to an electrical device, such as a battery management system (BMS). The temperature-sensitive battery connector may include a thermal switch device mounted to the connector body and thermally coupled to a terminal of the battery pack or battery cell. The thermal switch device may be configured to provide an over-temperature signal to the electrical device by modifying the signal transmitted by the at least one conductor when the temperature of the battery pack or battery cell exceeds a predetermined threshold temperature.

[0006] In another embodiment, an electrical system is disclosed. The electrical system may include multiple battery packs and a battery management system (BMS) for managing the multiple battery packs. Each of the multiple battery packs may have at least one battery terminal. The BMS may include a battery management controller and multiple status lines. The battery management controller may be configured to monitor the status of the battery packs via the status lines. Each of the multiple status lines may include a connector configured to couple to a battery terminal of a corresponding one of the battery packs. Each of the multiple status lines may include at least one conductor mounted to the connector, and the at least one conductor couples the connector to the battery management controller. Each of the multiple status lines may include a thermal switch device mounted to the connector. The thermal switch device may be thermally coupled to a battery terminal of a corresponding one of the battery packs. When the temperature of the corresponding one of the battery packs exceeds a predetermined threshold temperature, the thermal switch device may modify a signal from the battery terminal of the corresponding one of the battery packs to the battery management controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Specific implementations of the invention will now be described with reference to the following drawings, which are provided by way of example and not limitation.

[0008] Figure 1 is a schematic system diagram of a portion of an electrical system having one or more temperature sensors connected to corresponding battery packs.

[0009] Figure 2A is a perspective image of an electrical system comprising multiple interconnected battery packs to supply power to a load.

[0010] Figure 2B is an image showing an enlarged right side perspective view of the battery pack.

[0011] Figure 2C is an image showing an enlarged front perspective view of a battery pack.

[0012] Figure 3A is a schematic system diagram of a portion of an electrical system according to one embodiment.

[0013] Figure 3B is a schematic system diagram of an electrical system according to another embodiment.

[0014] Figure 4 yes Figure 3A An enlarged schematic diagram of a portion of the electrical system is shown.

[0015] Figure 5A is a schematic side cross-sectional view of a thermal switch device in a normal operating condition according to various embodiments.

[0016] Figure 5B yes Figure 5A Schematic circuit diagram of the thermal switch device shown in .

[0017] Figure 6A yes Figure 5A Schematic side sectional view of a thermal switch device in a fault state.

[0018] Figure 6B yes Figure 6A Schematic circuit diagram of the thermal switch device shown in .

[0019] Figure 7 is a graph illustrating current and temperature at which an exemplary switch trips from a normal operating condition to a fault condition, according to various embodiments.

[0020] Figure 8 is a diagram illustrating the relationship between temperature and resistance of an exemplary positive temperature coefficient (PTC) resistor according to various embodiments. DETAILED DESCRIPTION

[0021] Various embodiments disclosed herein relate to connectors with integrated thermal switching devices (e.g., thermal cutoffs (TCOs)) configured to detect overtemperature and / or overcurrent conditions in a battery pack or battery cell and relay the detection to an electrical device, such as a battery management system (BMS). In various embodiments, a temperature-sensitive battery connector is disclosed. The connector may include a connector body and at least one conductor mounted to the connector body and configured to transmit a signal by which the battery management system (BMS) determines that the temperature of the battery pack or battery cell has exceeded a threshold level. The connector may include a thermal switching device (e.g., a TCO) mounted to the connector body and thermally coupled to terminals of the battery pack or battery cell. The thermal switching device may be configured to provide an overtemperature signal to the BMS (or other type of electrical device) by interrupting voltage or current to provide a signal transmitted by at least one conductor used to balance one or more cells (or an array of cells) in the battery when the temperature of the battery pack or battery cell exceeds a threshold temperature. In various embodiments, for example, the signal transmitted to the BMS can be created by a change in resistance (e.g., a sudden increase in the resistance of a thermal switch device or TCO in the connector body). The BMS can be configured to interpret the signal as an increase in the temperature of the battery pack or battery cell and can issue an alarm indicating an overtemperature condition. In various embodiments, the BMS can shut down one or more (or all) of the cells in response to the alarm. By selecting the material and size of the thermal switch device, the threshold temperature can be pre-tuned and set for the device.

[0022] Figure 1 is a schematic system diagram of a portion of an electrical system 1 having one or more temperature sensors 21 attached to corresponding battery packs 6. The battery packs 6 can supply power to a load L. Each battery pack 6 can include one or more battery cells 2. An electrical device including a battery management system 25 can be connected to the positive terminal 20 of the corresponding battery pack 6 via a corresponding cell balancing line, which is also used as a cell voltage status signaling line (also referred to herein as a "status line 23") in the various embodiments disclosed herein. As shown, the positive terminal 20 of a particular battery pack 6 can be connected to the negative terminal 28 of an adjacent battery pack 6. The BMS 25 can receive a signal from the battery pack 6 along the status line 23 indicating the status of the battery pack 6 (e.g., the voltage status of the battery pack 6). For example, the approximate voltage of the battery pack 6 can be provided to the BMS 25 along the status line 23. In addition, as Figure 1 As shown schematically, a temperature sensor 21 (e.g., a thermistor) may be physically attached or mounted to the housing structure of the battery pack 6. The temperature sensor 21 may measure the temperature of the battery pack 6 to which the temperature sensor is connected, and may transmit the measured temperature (or a property associated with and derivable from the measurement value determined by the sensor 21) along a temperature sensing line 35 to the BMS 25. Based on the signal transmitted to the BMS 25 along the temperature sensing line 35, the BMS 25 may determine whether the battery pack 6 is experiencing an overtemperature condition and / or an overcurrent condition.

[0023] Therefore, in Figure 1 In the illustrated arrangement, the BMS 25 is connected to the positive terminal 20 of each battery pack 6 via a status line 23 and monitors the temperature of each battery pack 6 via a temperature sensor 21 and a temperature sensing line 35. The use of multiple thermistors 21 and additional temperature sensing lines 35 increases the cost and complexity of the electrical system 1. Furthermore, the temperature sensor 21 is typically mounted on the housing of the battery pack 6, which may have poor thermal conductivity, resulting in delayed and inaccurate measurements of the temperature of the cells 2 within the battery pack 6. Therefore, there remains a need for improved systems and methods for monitoring the temperature of a battery pack.

[0024] Figure 2A is an image of at least a portion of an electrical system 1 including a plurality of interconnected battery packs 6 to supply power to a load L (not shown). Figure 2B is an image showing an enlarged right side view of the battery pack 6 . Figure 2C 1 is an image showing an enlarged front perspective view of a battery pack 6. Each battery pack 6 may include one or more battery cells 2 (see Figure 3A), wherein each cell has one or more positive terminals 20 and one or more negative terminals 28 (see Figure 3A ).exist Figure 2A In the example of FIG, each battery pack 6 may include a plurality of cells having three contact points (e.g., positive terminals or negative terminals) to provide electrical communication to the BMS and / or the load L, however, any suitable number of contact points or terminals may be provided for each battery pack 6. Figure 2A As shown, a conductive bus bar 33 may be provided to electrically connect the positive terminal 20 of each battery pack 6 to the negative terminal 28 of an adjacent battery pack 6. Figure 2A As shown, the cable 37 can be connected to one of the positive terminals 20. The cable 37 can be configured to apply a high voltage from the series battery pack 6 to the load L. For example, the cable 37 can supply a voltage of at least 500 V to the load L, a voltage of at least 700 V to the load L, or a voltage of at least 1000 V to the load L.

[0025] Battery Cell 2 (See Figure 3A ) may include any suitable type of battery cells, including but not limited to lithium-ion battery cells. It will be appreciated that each battery pack 6 may include any suitable number of battery cells 2. For example, each battery pack 6 may include at least 100 cells, at least 200 cells, at least 300 cells, at least 400 cells, or at least 500 cells. In one example, each battery pack 6 may include approximately 500 cells arranged in ten groups of fifty (50) cells arranged in parallel with each other. Furthermore, it will be appreciated that any suitable number of battery packs 6 may be used in a larger electrical system 1 or system. For example, more than 100 battery packs (e.g., 150 battery packs 6, or 200 battery packs 6) may be used in the system. The electrical system 1 or system may include any suitable type of device for the load L, including but not limited to an electric or hybrid vehicle, an electric bicycle, a power tool, or any other suitable battery-powered device.

[0026] Figures 2A to 2C The battery pack 6 in may include a housing 30 that supports or encloses the battery cells. For example, in various embodiments, the housing 30 may include an inner cavity defined by (one or more) outer walls and shaped to accommodate one or more battery cells 2. The housing 30 may include any suitable type of material, such as a plastic material. In some embodiments, as described above, one or more temperature sensors 21 (e.g., thermocouples, thermistors, or any other suitable type of sensor) may be mechanically and thermally coupled to the housing 30 at a distance spaced from the terminals to avoid short circuiting, such as Figure 1 and Figure 2AThe temperature sensor 21 can monitor the temperature of the housing 30 , which can be used to correlate with the temperature of the battery cell 2 (which may be different from the measured temperature of the housing 30 ).

[0027] like Figures 2A to 2C As shown, the positive terminal 20 of each battery pack 6 can be electrically and mechanically connected to a status line 23 (e.g., a voltage or current sense line) via a connector 24. The connector 24 can include any suitable type of electrical connector, such as a conductive clip, a conductive ring, a conductive clamp, etc. For example, Figures 2B to 2C and Figure 4 As shown, conductive ring 22 may be used to secure connector 24 to positive terminal 20 of battery pack 6 to mechanically and electrically connect status wire 23 to positive terminal 20. Alternatively, in some embodiments, status wire 23 may be attached to negative terminal 28.

[0028] The status line 23 can provide electrical communication between the positive terminal 20 of the battery pack 6 and a battery management system (BMS) that is not in operation. Figures 2A to 2C As shown in (for example, see Figures 3A to 3B The BMS can receive a signal from the battery pack 6 along the status line 23 indicating the status of the battery pack 6. For example, the approximate voltage of the battery pack 6 can be provided to the BMS along the status line 23. Thus, in various embodiments, the BMS can be configured to monitor the status of the battery pack 6. The BMS can also transmit power to the battery pack 6 along the status line 23 to balance cells 2 that have become unbalanced. In various embodiments, for example, based on the state of charge of each battery pack 6, the BMS can transmit power along the status line 23 to balance the charge of the battery packs 6.

[0029] exist Figures 2A to 2C In an arrangement of , the sensor 21 may not provide a direct, accurate measurement of the temperature of the battery cell 2 because the sensor 21 is mounted to the housing 30 , which may comprise a plastic material and not be a good thermal conductor by design.

[0030] As this article combines Figures 3A to 4 As explained, the connector 24 can advantageously include a thermally activated switch that can monitor the temperature of the battery pack 6 directly at the battery pack 6, such as at the positive terminal 20 of the battery pack 6 (or at the negative terminal 28 of the battery pack 6). As explained herein, in various embodiments disclosed herein, the temperature sensor 21 and associated temperature sensing wire 35 can be omitted, which can reduce the cost and complexity of the device 1.

[0031] Figure 3Ais a schematic system diagram of a portion of an electrical system 1 according to one embodiment. Figure 4 yes Figure 3A An enlarged schematic diagram of a portion of the electrical system 1 is shown in . The illustrated portion of the electrical system 1 can supply power to a load L such as an electric vehicle, an electric bicycle, a power tool, or the like.

[0032] exist Figure 3A In the embodiment, the electrical device including the battery management system (BMS) 25 is electrically connected to the positive terminal 20 and the negative terminal 28 of the battery pack 6, which may include one or more cells 2. Although two cells 2 are in Figure 3A 1 and 2. The BMS 25 is shown in each battery pack 6, but any suitable number of cells may be provided per battery pack 6. The BMS 25 may include processing circuitry including circuitry defining one or more battery management controllers. Figure 3A Two complete battery packs 6 and a portion of a third battery pack are shown; however, as described above, the BMS 25 can be electrically connected to any suitable number of battery packs 6. As described above, the status line 23 can electrically connect the positive terminal 20 of the battery pack 6 to the BMS 25. In addition, the connector 24 can electrically and mechanically connect the status line 23 to the positive terminal 20 of the battery pack 6. However, as described above, the status line 23 can alternatively be connected to the negative terminal 28. Figure 2A Likewise, the bus bar 33 may electrically connect the positive terminal 20 of each battery pack 6 to the corresponding negative terminal 28 of an adjacent battery pack 6 .

[0033] However, with Figures 2A to 2C The arrangement is different. Figure 3A and Figure 4 In an embodiment, the connector 24 may include a connector body 27 coupled to the connector 24 or an integrated thermal switch device 3 formed within the connector body 27 of the connector 24, such as Figure 4 As shown. The connector 24 (eg, the connector body 27) may include an electrical conductor (such as metal) that is electrically and mechanically connected to the status line 23. Figure 4 As shown, the thermal switch device 3 and the connector body 27 can be mechanically and thermally connected to the positive terminal 20 of the battery pack 6 via a central thermally and electrically conductive ring 22 or via other thermally conductive fastening means. For example, a nut or other fastener can clamp the conductive ring 22 between the connector body 27 and the battery pack 6. Those skilled in the art will understand that additional ways of connecting the connector body 27 and the switch device 3 to the battery pack 6 may be suitable.

[0034] exist Figure 3A and Figure 4In the embodiment shown, the thermal switch device 3 is arranged in physical proximity to and thermally connected to the positive terminal 20 of the battery pack 6 and to the cells 2 of the battery pack 6. Figure 4 As shown, the thermal switch device 3 can be in physical contact with the terminal 20 of the battery pack 6 via a central heat-conducting ring 22 or other heat-conducting fastening device. In some embodiments, a thermal adhesive can also be provided between the thermal switch device 3 and the ring 22, and / or between the ring 22 and the terminal 20. Figure 4 As shown, a short thermal conduction path is provided directly between the thermal switch device 3 and the terminal 20 of the battery pack 6. Such a thermal conduction path can enable thermal energy (e.g., heat) to be efficiently transferred from the battery pack 6 (and the single cell 2) to the thermal switch device 3.

[0035] Thermal switch device 3 may include a switch 4 (such as a thermally activated switch) configured to move from a normally closed condition to an open condition when the temperature of the battery cell 2 exceeds a characteristic temperature threshold. Thermal switch device 3 may function as a thermal fuse and / or a thermal cut-off (TCO) device. Switch 4 may be configured to remain in the normally closed condition when the temperature of the battery cell 2 is below the temperature threshold. In the normally closed condition, cell balancing may be performed, and one or more condition signals from battery stack 6 may be transmitted to and monitored by BMS 25. Thus, by receiving and processing signals received from battery stack 6 along condition line 23, BMS 25 may determine that battery stack 6 is operating normally at a temperature below the threshold.

[0036] exist Figure 3A and Figure 4 In the example of FIG, the electrical device that monitors the temperature state of the battery pack 6 includes a BMS, but in other embodiments, the electrical device may include a motor, a transformer, a housing of an electrical component, or other suitable electrical device, where it is important to keep the temperature of the battery pack 6 or a single cell below a predetermined threshold temperature. In some embodiments, the connector 24 can be connected to multiple (e.g., two) electrical wires or status wires, and the tripping of the thermal switch device 3 can create an open circuit in the multiple status wires to indicate an overtemperature condition.

[0037] Thus, during operation, thermal energy from the battery pack 6 can be transferred to the thermal switching device 3 along a short, thermally conductive path with little or no heat loss. If the temperature of the battery pack 6 (and / or the individual cells 2 of the battery pack) is below a threshold temperature, the switch 4 can remain closed, and the BMS 25 (or other electrical device) receives a status signal from the battery pack 6 and can determine that the battery pack 6 is functioning properly. However, if the temperature of the battery pack 6 exceeds a predetermined temperature, the switch 4 can be moved to an open state, interrupting the signal along the status line 23 to the BMS 25. The BMS 25 can determine that the signal has been interrupted and can indicate to the user that the battery pack 6 may have experienced an over-temperature condition. Furthermore, opening the switch 4 can cause the BMS to initiate a process to interrupt the circuit between the electrical load L and the portion or all of the battery pack 6 that is experiencing the over-temperature condition, which can beneficially prevent further temperature increases to protect the battery pack 6 and the larger electrical system 1.

[0038] For example, in some embodiments, switch 4 can be opened in response to an increase in temperature, which can send a signal to BMS 25 resulting from a change in resistance (e.g., a sudden increase in resistance). In various embodiments, the current along condition line 23 can be suddenly reduced. For example, in some embodiments, an analog-to-digital converter (ADC) within BMS 25 can be programmed to calculate a voltage drop based on an increase in resistance, such as in a PTC resistor or other component of switch 4, which increases with increasing temperature. BMS 25 can be programmed to interpret the change in current and / or resistance as a voltage drop, and therefore as a warning or alarm signal indicating that a threshold value has been exceeded for the monitored cell(s). In response to an overtemperature alarm, BMS 25 can send a command to shut down some or all of the cells 2 in battery pack 6.

[0039] In some embodiments, switch 4 can be configured to be non-resettable, such that if switch 4 flips or trips from a normally closed state to an open state, switch 4 remains in the open state. In such an arrangement, when switch 4 is open, the voltage-related status signal sent to BMS 25, as well as the cell balancing function, may be permanently interrupted. Based on this interruption, BMS 25 may determine that battery pack 6 is in an overtemperature fault state. In some cases, the user may choose to replace the battery pack 6 that has experienced the temperature fault state. In other embodiments, switch 4 is manually resettable. For example, if switch 4 flips or trips to an open state, BMS 25 may indicate to the user that the signal along status line 23 has been interrupted, which may indicate an overtemperature condition. The user may inspect battery pack 6 and, if the temperature has sufficiently dropped, or if the overtemperature condition has otherwise been resolved, the user may reset switch 4 to a normally closed state, for example by pressing a button or engaging another interface.

[0040] In yet another embodiment, the switch 4 is resettable in an automatic manner, as shown below in conjunction with Figures 5A to 8 In some embodiments, as explained. Figures 5A to 6B As shown, the switch 4 may include a thermal switch element in parallel with a positive temperature coefficient (PTC) resistor, or various combinations of PTC, thermal cut-off (TCO) and / or thermal fuses arranged in parallel or in series. In other embodiments, the switch 4 may not include a PTC resistor. The switch 4 may have hysteresis properties (e.g., see Figure 8 ), the hysteresis property enables the switch 4 to move from the normally closed state to the open state when the temperature exceeds a characteristic threshold; and to move back from the open state to the normally closed state once the temperature drops below a reset threshold. In such an arrangement, the signal along the status line 23 from the battery pack 6 to the BMS 25 can be intermittently or temporarily interrupted. When the signal is interrupted, the BMS 25 can determine that the battery pack 6 is in an overtemperature state and can indicate the overtemperature state to the user. If the temperature drops sufficiently, the switch 4 can move back to the normally closed state, and the voltage signal and single cell balancing function to the BMS 25 can be restored. The BMS 25 can accordingly determine that the overtemperature state has subsided and the battery pack 6 is operating normally.

[0041] Beneficially, with Figure 1 A to Figure 2C Compared with the temperature sensor 21 shown in Figure 3A and Figure 4 The embodiment can more accurately determine whether the temperature of the battery pack 6 and the single cell 2 of the battery pack is too high. Figure 1 A to Figure 2CIn the arrangement of , the sensor 21 generally detects the temperature of the housing 30 and does not include a direct heat conduction path to the battery pack 6 and the individual cells of the battery pack. In contrast, in Figure 3A and Figure 4 In an embodiment, the thermal switch device 3 is integrated with the connector 24 and is disposed near the terminal 20 of the battery pack 6 and is in close thermal communication with the terminal. Therefore, the temperature of the thermal switch device 3 is closer to the temperature of the battery pack 6, at least in part due to the close thermal proximity of the thermal switch device 3 and the battery pack 6. In addition, the use of the thermal switch device 3 can advantageously disconnect (and in some embodiments close) the switch 4 so as to transmit the status of the battery pack 6 directly to the BMS 25, for example, whether the battery pack 6 is in a normal operating state or an over-temperature fault state. For example, as described above, the disconnection of the thermal switch device 3 can send a signal caused by a change in resistance (e.g., a sudden increase in resistance) to the BMS 25, which can be used as an alarm representing an over-temperature state. In some embodiments, the use of a switch device 3 integrated with the connector body 27 can avoid the use of a separate temperature sensor (such as a switch device 3 in combination with a BMS 25). Figure 1 A to Figure 2C The thermal switch device 3 may be configured to withstand a high voltage, including a voltage of at least 500 V, at least 750 V, or at least 1000 V. For example, the thermal switch device 3 may be configured to withstand a voltage in the range of 1 V to 2000 V, or a voltage in the range of 100 V to 1500 V.

[0042] Figure 3B is a schematic system diagram of an electrical system 1 according to another embodiment. Unless otherwise specified, Figure 3B The components can be used with Figure 3A and Figure 4 Like numbered parts are identical or substantially similar to those in Figure 3A and Figure 4 As with the embodiment of , a connector 24 may be provided. Figure 4 Likewise, the connector 4 may include the thermal switch element 3 as described above. Figure 3A and Figure 4 In a different embodiment, instead of being connected to a plurality of battery packs 6 having a plurality of cells 2, Figure 3B In the embodiment of FIG. 1 , the connector 24 can be connected to the positive terminal 26 of the individual battery cell 2. The BMS 25 (or other electrical device as described above) can be electrically connected to the positive terminal 26 and the negative terminal 29 of the battery cell 2. Figure 4 As shown, the status line 23 can provide electrical communication between the connector 24 and the BMS 25. Figure 3A and Figure 4The implementation method is the same as Figure 3B The embodiment of the present invention can similarly monitor the temperature of the battery cell 2. If the temperature of the battery cell 2 exceeds a predetermined threshold, the switch 4 can be opened and the signal to the BMS 25 can be interrupted. In addition, as described above, the switch 4 can be configured to be non-resettable, manually resettable, or automatically resettable.

[0043] Figures 5A to 8 Various embodiments are shown in which the switching device 3 is resettable in an automatic manner. However, as mentioned above, in other embodiments the switching device 3 may be non-resettable or resettable in a manual manner. Figure 5A is a schematic side sectional view of the thermal switch device 3 in a normal working state according to various embodiments. Figure 5B yes Figure 5A Schematic circuit diagram of the thermal switch device 3 shown in . Figure 6A yes Figure 5A Schematic side sectional view of the thermal switch device 3 in a fault state. Figure 6B yes Figure 6A The schematic circuit diagram of the thermal switch device 3 is shown in FIG. The thermal switch device 3 may include a switch 4 connected to a positive temperature coefficient (PTC) resistor 5. For example, in Figures 5A to 6B In the embodiment of the present invention, the switch 4 is connected in parallel with the PTC resistor 5, but in other embodiments, the PTC resistor 5 can be connected in other configurations. In other embodiments, there may be no PTC resistor 5 or parallel electrical path.

[0044] In the embodiment shown, the switch 4 is a heat-activated mechanical switch, in particular a bimetallic element. As explained herein, the PTC resistor 5 may comprise a resistive element whose resistance increases as the temperature increases. The PTC resistor 5 may be any suitable type of PTC resistor, including a ceramic PTC resistor or a polymer PTC resistor. Figure 5A and Figure 6A As shown, the thermal switch device 3 may include an electromechanical device including a housing 10 coupled to a first terminal T1 and a second terminal T2. The housing 10 may include a first conductive line 12 electrically connected to the second terminal T2 and the PTC resistor 5 via one or more interconnects 13.

[0045] The switch 4 may include a movable (eg, pivotable or bendable) conductive arm 8 and a switch element 7. The pivotable arm 8 may be electrically connected to the first terminal T1 and the switch element 7 via a contact portion. Figure 5A In the normal state shown, the pivotable arm 8 can electrically contact the central portion of the switch element 7. For example, in Figure 5A , the pivotable arm 8 is shown in a normal state, wherein the contact portion 15 on the distal end portion of the pivotable arm 8 contacts and is electrically connected to the first conductive line 12 and the second terminal T2. Figure 6A , the pivotable arm 8 is shown in a fault state in which the pivotable arm 8 is disconnected from the second terminal T2 and is in an open electrical configuration. In the fault state, the pivotable arm 8 may also be in electrical contact with the switch element 7 at its opposite end.

[0046] The pivotable arm 8 can be moved from the normal state to the fault state by engaging the switching element 7 and the PTC resistor 5. For example, the switching element 7 may comprise an electromechanical or thermomechanical switching element, in particular a dome-shaped bimetallic element, such as a disc having different metals on different sides, which changes shape in response to temperature changes. During normal operation, such as Figure 5A and Figure 5B As shown, a first current I1 can flow along the pivotable arm 8. Most of the current I2 passes through the second terminal T2, the first conductive line 12, and the pivotable arm 8 without passing through the PTC resistor 5. However, a small trickle current I3 (shown in dashed lines) flows from the second terminal T2 and the first conductive line 12 through the PTC resistor 5 and the switching element 7 to the pivotable arm 8. As described above, during normal operation, the current I2 bypassing the PTC resistor 5 may be much greater than the trickle current I3 passing through the PTC resistor 5.

[0047] If the temperature and / or current through the thermal switch device 3 exceeds a threshold value, the thermal switch device 3 can be switched from Figures 5A to 5B The normal working state shown in the Figures 6A to 6B For example, if the temperature of the switching element 7 exceeds a certain temperature threshold, which can be selected and tuned during the manufacturing process (such as by material and size selection), the switching element 7 can be turned off. Figure 5A Switch the downward curved shape to Figure 6A The PTC resistor 5 can also increase the temperature of the switching element 7, because increasing the current through the PTC resistor 5 causes the temperature of the PTC resistor 5 and the switching element 7 in contact with the PTC resistor 5 to increase. The corresponding relationship between resistance and temperature can be nonlinear, for example, Figure 8 As shown, at a threshold temperature (or temperature range), the resistance may increase significantly, resulting in a higher temperature rise. Figure 6A, the switch element 7 can move the pivotable arm 8 to the off configuration. Although the switch element 7 is shown as being bent downward in the normal state and bent upward in the fault state, it should be understood that in other arrangements, the thermal switch device can also be configured so that the switch element 7 is in an upward bent shape during the normal operating state and in a downward bent shape during the fault state.

[0048] During a fault configuration, the increased temperature of the PTC resistor 5 correspondingly increases the resistance and reduces the current flowing through the thermal switching device 3. As described below with respect to Figure 8 Explained in more detail, the trickle current I3 can provide a small amount of current from the battery pack or single cell to enable basic device functions because the heat generated by the PTC resistor 5 maintains a high temperature after the initial fault state to prevent the switch 4 from chattering, that is, preventing the switch from repeatedly switching between the fault mode and the normal operating mode. Therefore, in some embodiments, if chattering is problematic for the switching device, the PTC resistor 5 can be used. In other embodiments, if chattering is not a problem, the PTC resistor can be omitted, for example, the design of the bimetallic disc can be adjusted to avoid the use of the PTC resistor. Those skilled in the art will understand that the trickle current I3 through the PTC resistor 5 can have different amplitudes in the normal state and the fault state, and the amplitude of I3 can change during the occurrence of the fault state.

[0049] Figure 7 is a graph showing current and temperature when an exemplary switch 4 trips from a normal operating state to a fault state according to various embodiments. Specifically, Figure 7 Is used for Komatsulite TM Current vs. temperature plot for a dome-shaped bimetallic switch of a KCA Series A type circuit breaker available from Bourns, Inc. of Riverside, California. Specifically, Figure 7 Current versus temperature graphs are plotted for four different versions of Series A circuit breakers. Figure 7 In Figure 1, the lines represent the temperature and current combinations at which a particular circuit breaker trips to a fault condition. Therefore, the area below each line represents a normal condition, while the area at and above the line represents a fault condition. Figure 7 As shown, the switch 4 can be tripped from a normal operating state to a fault state when at a relatively high temperature (even at a low current) and / or at a relatively high current (even at a low temperature). For example, when the switch 4 reaches a preset threshold temperature in the range of 65° C. to 85° C. (or more specifically, in the range of 70° C. to 80° C., depending on the design), the switch 4 can be tripped from a normal operating state to a fault state.

[0050] In some embodiments, the use of a PTC resistor 5 can provide various advantages. As explained herein, the PTC resistor 5 can enable the switch 4 and the thermal switch device 3 to operate in a stable manner, such that the thermal switch device 3 maintains an elevated temperature after an initial fault condition without rapidly switching between normal and fault conditions. In contrast, due to hysteresis, in some cases, a significant decrease in the temperature of the switch device 3 may be required before the thermal switch device 3 can be reset from a fault condition to a normal operating condition.

[0051] Figure 8 FIG is a diagram illustrating the relationship between temperature and resistance of an exemplary PTC resistor according to various embodiments. Figure 8 As shown, at the predetermined fault temperature T f When the temperature is below 5000, the resistance R of the PTC resistor 5 PTC It can be at a relatively low level (but can be higher than the resistance Rs of the switch 4). As the temperature of the PTC resistor 5 reaches the predetermined fault temperature T f , resistor R PTC It will increase significantly with the increase of temperature. Figures 5A to 6B In the thermal switch device 3, the temperature increase of the PTC resistor 5 will further increase the temperature of the switching element 7 in contact with the PTC resistor 5. Therefore, the temperature increase of the PTC resistor 5 will accelerate or otherwise help the switching element 7 to change shape and trip. Figures 6A to 6B The fault condition is shown, thus providing a faster reaction time for the thermo-mechanical switch.

[0052] Advantageously, Figure 8 The hysteresis shown in can prevent the thermal switch device 3 from operating in the frequency hopping mode. In the frequency hopping mode, there is no Figure 8 As shown in the hysteresis, as the temperature decreases (even slightly), the temperature of the bimetallic switching element 7 will decrease and switch back to the normal working state prematurely. The increased current in the working state will again increase the temperature of the switching element 7 above the fault temperature T f , and the circuit breaker may repeatedly switch from a normal operating state to a fault state and back again. This frequency hopping pattern is undesirable and may cause instability in the larger electrical system or device 1.

[0053] therefore, Figures 5A to 6B The thermal switch device 3 may advantageously employ a PTC resistor 5 connected (eg, connected in parallel) to the switch 4 to maintain a stable operating state and a fault state. Figures 5A to 6BThe thermal switch device 3 can advantageously be resettable in some arrangements so that if the fault condition subsides (e.g., by a sufficient reduction in current and / or temperature), the circuit breaker 3 can return to a normal operating condition. Furthermore, as explained herein, the thermal switch device 3 can stably move to a fault condition and return to a normal operating condition without frequency bouncing.

[0054] In other embodiments, as described above, the thermal switch device 3 may be manually resettable or not resettable at all. In such embodiments, for example, there may be no PTC resistor in the thermal switch device 3 and no electrical path in parallel with the switch 4. In such an arrangement, if the switch 4 trips under a fault condition, the switch 4 may remain permanently in an open configuration to prevent current from flowing into and out of the BMS. In some embodiments, the thermal switch device 3 may include a button or other manual user interface to enable a user to manually reset the thermal switch device 3 to a normal operating configuration. Other arrangements for the thermal switch device 3 may be suitable.

[0055] Although the present invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the present invention extends from the specifically disclosed embodiments to other alternative embodiments and / or uses of the present invention, as well as obvious modifications and their equivalents. In addition, although several variations of the present invention have been shown and described in detail, other modifications within the scope of the present invention will be obvious to those skilled in the art based on this disclosure. It is also envisioned that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the present invention. It should be understood that the various features and aspects of the disclosed embodiments may be combined with or substituted for each other to form different modes of the disclosed invention. Therefore, the scope of the invention disclosed herein is not intended to be limited by the specifically disclosed embodiments described above, but should only be determined by a reasonable reading of the appended claims.

Claims

1. A temperature-sensitive battery connector, comprising: a connector body configured to mechanically connect to a terminal of a battery cell; at least one conductor mounted to the connector body and configured to transmit a signal from a battery pack or battery cell to an electrical device; as well as A thermal switch device is mounted to the connector body to be thermally coupled to the terminals of the battery pack or battery cell, wherein the thermal switch device is in physical contact with the terminals of the battery pack or battery cell via the at least one conductor mounted to the connector body to directly monitor the temperature of the battery pack or battery cell at the terminals of the battery pack or battery cell, and the thermal switch device is configured to provide an over-temperature signal to the electrical device by modifying the signal transmitted by the at least one conductor when the temperature of the battery pack or battery cell exceeds a predetermined threshold temperature.

2. The temperature-sensitive battery connector according to claim 1, wherein: The electrical device includes a battery management system (BMS).

3. The temperature-sensitive battery connector according to claim 1, wherein: When the temperature of the battery pack or battery cell is less than the predetermined threshold temperature, the signal transmitted by the at least one conductor to the electrical device includes a voltage condition signal.

4. The temperature-sensitive battery connector according to claim 1, wherein: The modified signal is a change in current through the at least one conductor.

5. The temperature-sensitive battery connector according to claim 4, wherein: The thermal switch device is configured to provide the over-temperature signal to the electrical device by varying a current through the at least one conductor.

6. The temperature-sensitive battery connector according to claim 1, wherein: The modified signal is caused by a change in the resistance of at least one component of the thermal switching device.

7. The temperature-sensitive battery connector according to claim 1, wherein: The thermal switch device is configured to provide a normal temperature signal to the device by transmitting the signal from the at least one conductor to the device when the temperature of the battery pack is below a threshold temperature.

8. The temperature-sensitive battery connector according to claim 1, wherein: The thermal switching device is a thermal fuse or a thermal cut-off (TCO) device.

9. The temperature-sensitive battery connector according to claim 1, wherein: The thermal switch device is not resettable.

10. The temperature-sensitive battery connector according to claim 1, wherein: The thermal switch device is manually resettable.

11. The temperature sensitive battery connector of claim 10, further comprising a user interface for manually resetting the thermal switch device when the thermal switch device is engaged by a user.

12. The temperature-sensitive battery connector according to claim 1, wherein: The thermal switch device is capable of being reset in an automatic manner.

13. The temperature-sensitive battery connector according to claim 12, wherein: The thermal switching device includes: a thermally activated switching element; and a positive temperature coefficient (PTC) resistor connected in parallel with the thermally activated switching element, and wherein the modified signal is indicative of a change in resistance of the PTC connected in parallel with the thermally activated switching element.

14. The temperature-sensitive battery connector according to claim 13, wherein: The thermally activated switching element comprises a bimetallic dome-shaped switching element.

15. The temperature-sensitive battery connector of claim 1, further comprising a conductive ring for mechanically and thermally connecting the connector body to the terminal of the battery pack or battery cell.

16. An electrical system comprising: Multiple battery packs; a battery management system (BMS), the battery management system being configured to manage the plurality of battery packs, each of the plurality of battery packs having at least one battery terminal, the BMS comprising: Battery Management Controller; and a plurality of status lines, wherein the battery management controller is configured to monitor the status of the battery pack via the status lines, and wherein each of the plurality of status lines comprises: a connector configured to couple to a battery terminal of a corresponding one of the battery packs; at least one conductor mounted to the connector and coupling the connector to the battery management controller; and a thermal switch device mounted to the connector, wherein The thermal switch device is thermally coupled to the battery terminal of the corresponding one of the battery packs, wherein the thermal switch device is in physical contact with the battery terminal of the corresponding one of the battery packs via the at least one conductor mounted to the connector to directly monitor the temperature of the corresponding one of the battery packs at the battery terminal of the corresponding one of the battery packs, wherein when the temperature of the corresponding one of the battery packs exceeds a predetermined threshold temperature, the thermal switch device modifies the signal from the battery terminal of the corresponding one of the battery packs to the battery management controller.

17. The electrical system of claim 16, wherein: The battery management controller is configured to sense that at least one of the battery packs is at a temperature exceeding the predetermined threshold temperature based on detecting an open circuit state of at least one of the status lines.

18. The electrical system of claim 16, wherein: The thermal switch device in each status line is integrated with the connector of each corresponding status line.

19. The electrical system of claim 16, wherein: The thermal switching device is a thermal fuse or a thermal cut-off (TCO) device.

20. The electrical system of claim 16, wherein: The thermal switch device is not resettable.

21. The electrical system of claim 16, wherein: The thermal switch device is manually resettable.

22. The electrical system of claim 21 further comprising a user interface for manually resetting the thermal switch device when the thermal switch device is engaged by a user.

23. The electrical system of claim 16, wherein: The thermal switch device is capable of being reset in an automatic manner.

24. The electrical system of claim 23, wherein: The thermal switching device includes: a thermally activated switching element; and a positive temperature coefficient (PTC) resistor connected in parallel with the thermally activated switching element.

25. The electrical system of claim 24, wherein: The thermally activated switching element comprises a bimetallic dome-shaped switching element.

26. The electrical system of claim 16, further comprising a conductive ring for mechanically and thermally connecting the connector to the terminal of the battery pack or battery cell.

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