Battery stress mitigation system with bypass

Abstract

To provide a power system for relieving battery stress.SOLUTION: The power system includes a battery charging path and a capacitor charging path arranged in parallel. During an inrush event, a current limiting element limits current flow along a battery charging path to mitigate battery stress. During an inrush event, current flow between the battery and the load along the bypass path is also prevented by the switch element. Under steady state charging conditions, the resistance of the current limiting element decreases, thus increasing the current flow between the battery and the load along the battery charging path. During steady state, a switch circuit controls operation of the switch element to also enable current flow between the battery and the load along the bypass path. The change in resistance of the current limiting element and / or the actuation of the switch element by the switch circuit is optionally based on a change in temperature and is achieved passively without requiring an external control input signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of the filing date of U.S. Provisional Patent Application No. 63 / 016,087, filed April 27, 2020, the disclosure of which is incorporated herein by reference in its entirety. [Background technology]

[0002] background Rapid charging and discharging can adversely affect the health of a battery, especially if it occurs during use of the battery under high power loads. Such inrush events can occur, for example, as a result of a sudden demand from a load (e.g., when electrical contact is first established between the battery and the load) or as a result of a sudden inrush of current into a battery being charged.

[0003] For electric vehicles (EVs), battery stress can be a particular concern given the high power demands on the main battery and the battery's frequent exposure to in-rush events during operation (e.g., EV acceleration, regenerative braking, etc.). Degraded battery performance and capacity can result in reduced vehicle performance and ultimately lead to premature, potentially costly battery replacement. Summary of the Invention

[0004] overview According to one embodiment of the present disclosure, a power system for a vehicle includes a battery charging path and a capacitor charging path arranged in parallel. The battery charging path is configured to provide current from the battery to a load. The capacitor charging path is configured to provide current from the capacitor to the load. A current-limiting element having a variable resistance is arranged in series along the battery charging path. The charge system further includes a bypass system. The bypass system includes a bypass path arranged in parallel with the battery charging path. A switch element is arranged along the bypass path. The switch element is configured to selectively prevent and allow current flow along the bypass path. The current-limiting element is defined by a resistance that substantially limits current flow between the battery and the load, while simultaneously preventing current flow along the bypass path.

[0005] In some embodiments, when the current-limiting element is defined by a resistance that substantially limits current flow between the battery and the load, the current flow between the battery and the load is less than the current flow along the capacitor charging path. Optionally, the current-limiting element is defined by a low resistance that allows current to flow between the battery and the load while allowing current flow along the bypass path. In some embodiments, when the switch circuit is activated to allow current flow along the bypass path, there is substantially no current flow between the capacitor and the load along the capacitor charging path.

[0006] In various embodiments, the switch circuit includes a temperature variable element having a resistance that changes in response to a first change in temperature. The change in resistance is optionally achieved without applying an external control input signal to the temperature variable element. In some embodiments, the current-limiting element includes a temperature sensitive element having a resistance that changes in response to a second change in temperature. The first change in temperature may be the same as the second change in temperature. Alternatively, the first change in temperature may be different from the second change in temperature.

[0007] The temperature variable element optionally comprises a positive temperature coefficient thermistor, and the temperature sensitive element optionally comprises a negative temperature coefficient thermistor. When the core of the temperature variable element reaches a predetermined temperature, the resistance of the temperature variable element increases in response. When the core of the temperature sensitive element reaches a predetermined temperature, the resistance of the temperature sensitive element decreases in response.

[0008] According to various aspects, the switch element includes a semiconductor switch. A change in the resistance of the temperature variable element is optionally configured to vary a voltage signal applied to a gate of the semiconductor switch. The current-limiting element may optionally include a temperature sensitive element. In response to a core of the temperature sensitive element reaching a temperature above a first threshold temperature range, the resistance of the temperature sensitive element may decrease.

[0009] In response to the core of the temperature variable element reaching a temperature above a second threshold temperature range, a voltage signal applied to a gate of the semiconductor switch is optionally activated to allow current flow through the bypass path. The second threshold temperature range corresponds to a temperature higher than the temperature of the first threshold temperature range. In response to the temperature of the core of the temperature variable element exceeding the second threshold temperature range, the resistance of the temperature variable element optionally increases.

[0010] In some embodiments, the switch circuit further includes a power source and a resistor disposed in series with the temperature variable element, which is optionally physically connected directly to the battery charging path.

[0011] According to another embodiment of the present disclosure, a power pack assembly includes a housing and a power system supported by the housing. The housing includes a first portion configured to house a battery and a second portion configured to house a capacitor. The power system includes a battery charging path, a capacitor charging path, a current limiting device, and a bypass system. The battery charging path extends between the first portion of the housing and a terminal supported by the housing. The capacitor charging path is disposed in parallel with the battery charging path and extends between the second portion of the housing and the terminal.

[0012] The current limiting element has a variable resistance and is disposed in series along the battery charging path. The bypass system includes a bypass path, a switch element, and a switch circuit. The bypass path is disposed in parallel with the battery charging path. The switch element is disposed along the bypass path. The switch element is configured to selectively limit and allow current flow along the bypass path. The switch circuit is configured to operate the switch element to limit current flow along the bypass path.

[0013] The power pack assembly also optionally includes a battery and a capacitor. The battery is housed within the first portion of the housing and connected to the terminals by a battery charging path. The capacitor is housed within the second portion of the housing and connected to the terminals by a capacitor charging path. The switch circuit optionally includes a temperature variable element having a variable resistance. The switch circuit is configured to operate a switch element in response to a change in core temperature of the temperature variable element to selectively restrict and allow current flow along the bypass path.

[0014] According to another embodiment of the present disclosure, a method of charging a load includes causing current from a battery to flow through a current-limiting element located along a battery charging path coupling the battery to the load. The current is caused to flow from a capacitor to the load. The capacitor is located in parallel with the current-limiting element. Activating a switch circuit causes the switch element to flow current between the battery and the load along a bypass path disposed in parallel with the battery charging path. The switch circuit activates the switch element to cause current from the battery to flow along the battery charging path to the battery while simultaneously allowing current flow between the battery and the load along the bypass path.

[0015] The current limiting element optionally includes a temperature sensitive element, and the switch circuit optionally includes a temperature variable element. The switch circuit activates the switch element based on a change in resistance of the temperature variable element. When the temperature of the core of the temperature variable element reaches a first temperature, a change in the resistance of the temperature variable element occurs in response. The temperature sensitive element causes current to flow along the battery charging path based on a decrease in the resistance of the temperature sensitive element. When the core temperature of the temperature sensitive element reaches a second temperature, a change in the resistance of the temperature sensitive element occurs in response. After current flow from the capacitor to the load stops, the core of the temperature sensitive element reaches the first temperature. Before current flow from the capacitor to the load stops, the core of the temperature sensitive element reaches the second temperature.

[0016] [The present invention 1001] a battery charging path configured to provide current from the battery to a load, and a capacitor charging path configured to provide current from the capacitor to the load, arranged in parallel with each other; a current limiting element having a variable resistance disposed in series along the battery charging path; and Bypass System Including, The bypass system comprises: a bypass path disposed in parallel with the battery charging path; a switch element disposed along the bypass path and configured to selectively prevent and allow current flow along the bypass path; and Switch Circuit Including, The current limiting element is defined by a resistor that substantially limits current flow between the battery and the load, while the switch circuit is configured to prevent current flow along the bypass path. [The present invention 1002] A power system of the present invention 1001, wherein when a current limiting element is defined by a resistor that substantially limits the current flow between the battery and the load, the current flow between the battery and the load is less than the current flow along the capacitor charging path. [The present invention 1003] The power system of the present invention 1001, wherein the switch circuit is configured to allow current flow along a bypass path while a current limiting element is defined by a low resistance that allows current to flow between the battery and the load. [The present invention 1004] The power system of the present invention 1003, wherein when the switch circuit is activated to allow current flow along the bypass path, there is substantially no current flow along the capacitor charging path between the capacitor and the load. [The present invention 1005] The power system of the present invention 1001, wherein the switch circuit includes a temperature variable element having a resistance that changes in response to a first change in temperature. [The present invention 1006] The power system of the present invention 1005, wherein the change in resistance is achieved without applying an external control input signal to the temperature variable element. [The present invention 1007] The power system of the present invention 1005, wherein the current limiting element includes a temperature sensitive element having a resistance that changes in response to a second change in temperature. [The present invention 1008] the temperature variable element includes a positive temperature coefficient thermistor and the temperature sensitive element includes a negative temperature coefficient thermistor; when the core of the temperature variable element reaches a predetermined temperature, the resistance of the temperature variable element increases in response; When the core of the temperature sensitive element reaches a predetermined temperature, the resistance of the temperature sensitive element decreases in response. The power system of the present invention 1007. [The present invention 1009] The power system of the present invention 1005, wherein the switching element includes a semiconductor switch. [The present invention 1010] The power system of the present invention 1009, wherein a change in the resistance of the temperature variable element is configured to change the voltage signal applied to the gate of the semiconductor switch. [The present invention 1011] the current limiting element includes a temperature sensitive element; a resistance of the temperature sensitive element decreases in response to the core of the temperature sensitive element reaching a temperature above a first threshold temperature range; The power system of the present invention 1010. [The present invention 1012] a voltage signal applied to a gate of the semiconductor switch is activated in response to the core of the temperature variable element reaching a temperature above a second threshold temperature range, thereby allowing current flow through the bypass path; the second threshold temperature range corresponds to a temperature higher than the temperature of the first threshold temperature range; The power system of the present invention 1011. [The present invention 1013] The power system of the present invention 1012, wherein the resistance of the temperature variable element increases in response to the temperature of the core of the temperature variable element exceeding a second threshold temperature range. [The present invention 1014] The power system of the present invention 1010, wherein the switch circuit further includes a power source and a resistor disposed in series with the temperature variable element. [The present invention 1015] The power system of the present invention 1010, wherein the temperature variable element is physically connected directly to the battery charging path. [The present invention 1016] a housing having a first portion configured to house a battery and a second portion configured to house a capacitor; and A power system supported by the housing. 1. A power pack assembly comprising: The power system comprises: a battery charging path extending between the first portion of the housing and a terminal supported by the housing; a capacitor charging path disposed in parallel with the battery charging path and extending between the second portion of the housing and the terminal; a current limiting element having a variable resistance disposed in series along the battery charging path; and Bypass System Including, The bypass system comprises: a bypass path disposed in parallel with the battery charging path; a switch element disposed along the bypass path and configured to selectively restrict and allow current flow along the bypass path; and a switch circuit configured to actuate the switch element to limit current flow along the bypass path; Including, Power pack assembly. [The present invention 1017] further comprising a battery and a capacitor; the battery is contained within the first portion of the housing and connected to the terminals by a battery charging path; the capacitor is contained within the second portion of the housing and is connected to the terminal by a capacitor charging path; The power pack assembly of the present invention 1016. [The present invention 1018] the switch circuit includes a temperature variable element having a variable resistance; the switch circuit is configured to actuate a switch element in response to a change in temperature of the core of the temperature variable element to selectively restrict and allow current flow along a bypass path; The power pack assembly of the present invention 1016. [The present invention 1019] directing current from the battery through a current limiting device located along a battery charging path coupling the battery to a load; causing a current to flow from a capacitor located in parallel with the current limiting element to the load; and activating a switch circuit to cause a switch element to allow current to flow between the battery and the load along a bypass path disposed in parallel with the battery charging path; Including, the switch circuit operates the switch element to allow current to flow from the battery along the battery charging path to the battery while simultaneously allowing current flow between the battery and the load along the bypass path; A method for charging a load. [The present invention 1020] The current limiting element includes a temperature sensitive element and the switch circuit includes a temperature variable element; the switch circuit operates a switch element based on a change in resistance of the temperature variable element; a change in the resistance of the temperature variable element occurs in response to the temperature of the core of the temperature variable element reaching a first temperature; the temperature sensitive element causes a current to flow along a battery charging path based on a decrease in resistance of the temperature sensitive element; a change in the resistance of the temperature sensitive element occurs in response to a core temperature of the temperature sensitive element reaching a second temperature; the core of the temperature variable element reaches the first temperature after current flow from the capacitor to the load has stopped; the core of the temperature sensitive element reaches the second temperature before current flow from the capacitor to the load stops. The method of the present invention 1019. This summary is merely illustrative and is not intended to be limiting in any way. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, read in conjunction with the accompanying drawings, in which like numerals refer to like elements. [Brief explanation of the drawings]

[0017] Various objects, aspects, features, and advantages of the present disclosure will become more apparent and will be better understood by reference to the detailed description read in conjunction with the accompanying drawings, in which like reference numerals identify corresponding elements throughout the drawings, and in which like reference numerals generally indicate identical, functionally similar, and / or structurally similar elements.

[0018] [Figure 1] FIG. 1 is a diagram of a power system according to one embodiment. [Figure 2] 1 is an exemplary graph showing resistance of a temperature sensitive element versus temperature, according to one embodiment. [Figure 3] 1 is an exemplary graph comparing current flow from a charging system and elements of a charge system, according to one embodiment. [Figure 4] FIG. 1 is a circuit diagram of a power system according to one embodiment. [Figure 5] 1 is a circuit diagram of a high-power vehicle system utilizing a power system according to one embodiment. [Figure 6] 1 illustrates a power pack system incorporating a power system according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] explanation Referring generally to the drawings, a power system 10 including a charge system 100 and a bypass system 400 is shown and described in accordance with various aspects. In general, the charge system 100 relieves battery stress during an in-rush event (e.g., when an electrical connection is first established between the battery and the load). During steady-state operation, the bypass system 400 increases the efficiency of the power system 10 by providing an unrestricted current flow path through which current can be supplied between the battery and the load.

[0020] 1, charging system 100 includes a battery 102 and a capacitor 106 arranged in parallel. A battery charging path 103 connects the battery to a load 108, and a capacitor charging path 105 connects capacitor 106 to the load 108 and battery 102.

[0021] Capacitors typically have a relatively low internal resistance, allowing them to respond quickly to inrush events. Thus, the series arrangement of the capacitor 106 and the battery 102 in the charging system 100 allows the capacitor 106 to provide current during an inrush event (e.g., when electrical contact is first established between the charging system 100 and the load 108) and the battery 102 to gradually increase the current as the load 108 reaches a steady-state level of charge. Once the steady-state level of charge is reached, the battery 102 takes over as the primary source of current to the load 108.

[0022] The percentage of current flow provided to the load 108 by the battery 102 and capacitor 106, individually, depends on the difference between the effective resistance of the battery charging path 103 and the effective resistance of the capacitor 106. In a circuit consisting only of a capacitor and a battery, the effective resistance of the battery charging path matches the internal resistance of the battery, and the effective resistance of the capacitor matches the internal resistance of the capacitor. Thus, if the difference between the internal resistance of the battery and the internal resistance of the capacitor is small, the battery can still provide a significant portion (e.g., approximately half) of the current to the load during an inrush event. Depending on the power requirements of the load, this reduction in current flow from the battery during an inrush event may be insufficient to protect the battery from damage.

[0023] In contrast to batteries, capacitors suffer minimal wear and degradation when exposed to inrush current. Therefore, as shown in FIG. 1 , charging system 100 further includes current-limiting element 104, which increases the effective resistance of battery charging path 103 relative to the effective resistance of capacitor 106. Thus, as described below with reference to FIG. 3 , current-limiting element 104 increases the rate and amount at which capacitor 106 is used to meet the current demands of load 108 during an inrush event, thereby limiting the rate and amount of current drawn from battery 102. By extending the time that capacitor 106 is utilized as the primary source of current to load 108 during an inrush event, current-limiting element 104 advantageously allows battery 102 to gradually increase its current supply to load 108 in a manner that does not jeopardize its health. Once a steady-state level of charge is reached, battery 102 can also safely take over as the primary source of current to load 108.

[0024] The current-limiting element 104 can be defined by a variety of different resistive elements. For example, according to some embodiments, the current-limiting element 104 includes a resistor (e.g., thick film, thin film, wirewound, carbon composite, etc.) having a fixed resistance value. Because a resistor does not require any additional elements or external control input signals for its operation, the resistor allows the current-limiting element 104 to be easily and cost-effectively incorporated into the charge system 100.

[0025] While the resistance provided by current-limiting element 104, which includes a resistor, is advantageous during inrush events, continuous limitation of current flow between battery 102 and load 108 during steady-state charging conditions is often undesirable. Thus, in other embodiments, current-limiting element 104 alternatively includes an active element having a resistance that can be varied in response to an external control input signal (e.g., received via a controller, manual adjustment, etc.). Examples of such active elements include a rheostat, a potentiometer, a digital resistor, a field-effect transistor operating in linear mode, etc.

[0026] By allowing the effective resistance of the battery charging path 103 to decrease after an inrush event, a current-limiting element 104 including an active element advantageously increases the efficiency and speed with which the battery 102 can supply current to the load 108 under steady-state charging conditions. However, the increased component count, complexity, and cost associated with incorporating the external input sources required for the operation of an active element may limit the suitability of using an active element as the current-limiting element 104 in various situations.

[0027] According to various aspects, the current-limiting element 104 advantageously includes a temperature-sensitive element (e.g., a negative temperature coefficient thermistor) that changes in a predictable manner in response to changes in temperature. As representatively shown by the graph in FIG. 2, a current-limiting element 104 including a temperature-sensitive element has a large resistance at an initial low temperature. As the core temperature of the temperature-sensitive element increases to a threshold temperature range, the resistance of the temperature-sensitive element decreases nonlinearly (e.g., exponentially). Once the core temperature exceeds the threshold temperature range, the temperature-sensitive element operates in a steady-state flow state in which the temperature-sensitive element offers minimal (e.g., zero) resistance to current flow from the battery 102 to the load 108.

[0028] An increase in the core temperature of the current-limiting element 104, which includes a temperature sensitive element, can occur as a result of heat dissipation through the temperature sensitive element during current flow. An increase in the core temperature of the temperature sensitive element can also occur as a result of changes in ambient temperature. For example, the core temperature of the temperature sensitive element can increase as a result of heat generation by the load 108 or other elements of the charge system 100 during operation. According to some embodiments, the temperature sensitive element is optionally connected to the load 108 through a heat sink to increase the responsiveness of the temperature sensitive element to changes in ambient temperature.

[0029] The initial resistance of the temperature sensitive element and the threshold temperature range at which the temperature sensitive element reaches a steady-state flow state vary based on the structure of the temperature sensitive element. Thus, by selecting a temperature sensitive element appropriate for the operating parameters and conditions of the load 108 in which the charging system 100 is used, a current-limiting element 104 including a temperature sensitive element can provide the benefits of both a fixed resistance resistor and an active element while avoiding the limitations of each of these options.

[0030] That is, like current-limiting elements 104 including active elements, current-limiting elements 104 including temperature-sensitive elements can provide varying degrees of resistance to current flow, thus allowing for a reduction in the effective resistance of the battery charging path 103 after an inrush event. Moreover, in contrast to active elements, temperature-sensitive elements do not require receipt of an external control input signal; rather, they passively change their resistance in response to changes in temperature. Thus, like current-limiting elements 104 including resistors, this elimination of the need for additional or external control elements allows current-limiting elements 104 including temperature-sensitive elements to be easily and cost-effectively incorporated into charging systems 100.

[0031] 3 shows graphs illustrating current flow from the battery and capacitor of a charging system 100 that does not include a current-limiting element 104 and a charging system 100 that includes a current-limiting element 104 that includes a temperature-sensitive element during an inrush event. A first curve 310 shows a time response curve of current flow from the battery of the charging system. A second curve 320 shows a time response curve of current flow to / from the capacitor of the charging system. A third curve 330 shows a time response curve of current flow from the battery 102 of the charging system 100. A fourth curve 340 shows a time response curve of current flow to / from the capacitor 106 of the charging system 100.

[0032] As illustrated by the graph in FIG. 3, in both the charging system (without the current-limiting element 104) and the charging system 100 (with the current-limiting element 104 including the temperature-sensitive element), the capacitor is the primary source of current at the beginning of an inrush event. As the capacitor gradually depletes and the battery increases its discharge, equilibrium points 301, 302 are reached. The equilibrium points 301, 302 correspond to the time when the amount of current supplied by the capacitor equals the amount of current supplied by the battery. After the occurrence of equilibrium points 301, 302, the amount of current supplied by the battery begins to exceed the amount of current provided by the capacitor. The capacitor continues to supply current to the load until transition points 303, 304 are reached. After the occurrence of transition points 303, 304, the capacitor stops supplying current to the load and instead begins to draw current from the battery (evidenced by the positive current value of the current flow for the capacitor). The battery continues to supply current to the battery and capacitor until a recharge point 305, 306 is reached (corresponding to the point at which the capacitor has been recharged by the battery), after which the current drawn by the battery achieves a steady state flow to the load.

[0033] 3, the charging system (without the current-limiting element 104) and the charge system 100 (with the current-limiting element 104 including the temperature sensitive element) achieve their respective transition points 303, 304 and recharge points 305, 306 at similar times. Therefore, the incorporation of the current-limiting element 104 into the charge system 100 does not adversely affect the time it takes for the battery 102 to recharge the capacitor 106 after an inrush event.

[0034] However, as shown by a comparison of the first curve 310 and the third curve 330, in the absence of the current-limiting element 104 to increase the effective resistance to flow between the battery 102 and the load 108, the rate of current flow from the battery in the charging system (which does not include the current-limiting element 104) is significantly greater than the rate of current flow from the battery 102 in the charging system 100. Thus, as shown by a comparison of the second curve 320 and the fourth curve 340, the amount of current supplied by the capacitor in the charging system is much less than the amount of current supplied by the capacitor 106 in the charging system 100. As a result of these changes in the charging system and the rate at which current is supplied between the capacitor and battery elements of the charging system 100, the charging system reaches its equilibrium point 301 much sooner than the charging system 100 reaches its equilibrium point 302.

[0035] 3 , comparing the amounts of energy individually supplied by the capacitor and battery of the charging system and charging system 100, respectively (represented by the area under each curve between the start of the inrush event and the occurrence of transition points 303, 304), the amount of energy supplied by the capacitor of the charging system (see callout A) is substantially less than the amount of energy supplied by the battery of the charging system (see callout B). In contrast, the amount of energy supplied by the capacitor 106 of the charging system 100 (see callout C) is substantially greater than the amount of energy supplied by the battery 102 of the charging system 100 (see callout D). Thus, as shown by a comparison of callout B of the first curve 310 and callout D of the third curve 330, the energy demand on the battery 102 of the charging system 100 (including the current-limiting element 104) is substantially less than the energy demand on the battery of the charging system without the current-limiting element 104.

[0036] As noted above, in embodiments in which the current-limiting element 104 includes a fixed resistor, current is limited both during an inrush event and during subsequent steady-state charging. Charge system 100 embodiments that include a current-limiting element 104 that includes an active or temperature-sensitive element advantageously allow the effective resistance of the battery charging path 103 to be reduced after an inrush event, but such current-limiting element 104 embodiments may still provide some residual resistance to current flow during steady-state charging. As a result, the current-limiting element 104 may cause heat dissipation when current from the battery 102 flows to the load 108, which may in turn reduce the efficiency of the charge system 100.

[0037] 1, in accordance with various aspects, the power system 10 also includes a bypass system 400 that allows current to flow unrestricted from the battery 102 to the load 108 after an inrush event. As shown in FIG. 1, the bypass system 400 includes a bypass path 401 having a switch element 403 disposed in parallel with the battery charging path 103. The switch element 403 is selectively controllable to allow unrestricted current flow from the battery 102 to the load 108 during a steady-state charging condition. On the other hand, during an inrush event, the switch element 403 limits current flow through the bypass path 401 to enable the charging system 100 to minimize stress on the battery 102 in the above manner.

[0038] The switch circuit 420 of the bypass system 400 is functionally connected to the switch element 403 to effect transition of the switch element 403 between a flow state (current is diverted from the battery 102 to the load 108 via the bypass path 401) and a no-flow state (current flow through the bypass path 401 is limited, e.g., prevented) based on the operating state of the charge system 100 (i.e., steady level, inrush event, etc.).

[0039] The switch element 403 may be defined by a variety of different structures, elements, and features. For example, the switch element 403 may be controllable via a voltage-based signal, a current-based signal, etc. The switch element 403 may be normally open or normally closed. As described with reference to the example bypass system 400 of FIG. 4, the switch element 403 optionally includes a semiconductor switch 405. According to other embodiments, the switch element 403 optionally includes a relay switch. In still other embodiments, the switch element 403 may be defined by a variety of other structures.

[0040] Switch circuit 420 may utilize many different elements, structures, and arrangements to functionally control switch element 403 to implement a flow or no-flow state of bypass path 401. For example, switch circuit 420 may include a controller that sends a control input signal to switch element 403 based on one or more measured or sensed parameters (e.g., detected current, voltage, temperature levels, state of capacitor 106, etc.).

[0041] During operation of the charging system 100 to charge the load 108, heat is gradually generated as current flows through the charging system 100 to the load 108. As noted above, in accordance with various aspects, the current-limiting element 104 advantageously comprises a temperature-sensitive element that utilizes the increasing heat generated during powering of the load 108 during operation of the charging system 100 to passively (i.e., without the need for an external control input signal) vary the resistance of the battery charging path 103 in a desired manner.

[0042] In a similar manner, switch circuit 420 also optionally utilizes the increase in temperature that occurs during charging of load 108 to control the operation of switch element 403 using temperature variable element 421. Thus, just as current-limiting element 104 including a temperature sensitive element eliminates the need for complex and costly arrangements to achieve changes in its resistance, the use of temperature variable element 421 also provides switch circuit 420 with a simple and cost-effective option by which it can achieve the desired control of switch element 403.

[0043] The manner in which the change in resistance of the temperature variable element 421 causes the switch circuit 420 to transition the switch element 403 between a flow state and a no-flow state can be achieved using a variety of different elements and arrangements. Generally, operation of the switch circuit 420 is based on the temperature variable element 421 achieving a resistance that falls within a predetermined effective resistance range. Once a resistance that falls within the effective resistance range is achieved, the selection and arrangement of the other elements of the switch circuit 420 are configured to enable the switch circuit 420 to achieve the desired transition of the switch element 403. In such a manner, the temperature variable element 421 can also actuate the switch element 403 without requiring an external control input signal.

[0044] As noted above, current flow through bypass path 401 is desirably prevented during an inrush event to minimize the rate and amount of energy provided by battery 102 to load 108 during the inrush event. Accordingly, in various embodiments, the structure of temperature variable element 421 is selected so that the threshold temperature range at which temperature variable element 421 achieves a resistance that falls within the effective resistance range corresponds to a temperature range having a minimum temperature equal to or greater than the expected temperature of charge system 100, load 108, and / or the ambient environment during steady-state charging conditions.

[0045] To enhance the responsiveness of the temperature variable element 421 to changes in temperature resulting from operation of the charge system 100, the temperature variable element 421 is optionally located in close proximity to the battery 102, the current-limiting element 104, and / or the load 108. Additionally or alternatively, the temperature variable element 421 is optionally connected to the charge system 100 and / or the load 108 via a heat sink or other heat transfer device. For example, the temperature variable element 421 is optionally physically connected to a portion of the battery charging path 103 extending between the current-limiting element 104 and the load 108 to enhance the ability of the temperature variable element 421 to respond to changes in temperature that occur as heat is dissipated by the current-limiting element 104.

[0046] In various embodiments, the temperature variable element 421 comprises a positive temperature variable element (e.g., a posistor or positive temperature coefficient resistor) defined by a low resistance at low temperatures and a high resistance when the temperature of its core exceeds a threshold temperature range. In embodiments in which the current-limiting element 104 of the charging system 100 in which the bypass system 400 is used comprises a temperature sensitive element, the structure of the positive temperature variable element defining the temperature variable element 421 is optionally selected so that the positive temperature variable element achieves a resistance that falls within an effective resistance range at a threshold temperature range higher than the threshold temperature range at which the resistance of the temperature sensitive element defining the current-limiting element 104 undergoes its resistance transition. Such a configuration of the temperature variable element 421 including a positive temperature variable element may prevent operation of the switch element 403 that enables flow through the bypass path 401 during an inrush event.

[0047] According to other embodiments, the temperature variable element 421 alternatively comprises a negative temperature variable element. The negative temperature variable element functions in a manner similar to the temperature sensitive element described with reference to the current-limiting element 104 of the charging system 100, in that the resistance of the negative temperature variable element decreases above a threshold temperature range. In embodiments in which the current-limiting element 104 of the charging system 100 comprises a temperature sensitive element, the temperature sensitive element defining the current-limiting element 104 and the negative temperature variable element defining the temperature variable element 421 may be defined by the same or similar structures. Optionally, in some such embodiments, the negative temperature variable element defining the temperature variable element 421 is configured to achieve a resistance that falls within an effective resistance range at a threshold temperature range higher than the threshold temperature range at which the resistance of the temperature sensitive element defining the current-limiting element 104 decreases, to avoid premature activation of the switch element 403 that would allow current to flow through the bypass path 401.

[0048] The selection and arrangement of additional elements defining switch circuit 420 depend on the characteristics of switch element 403 (e.g., construction of switch element 403, biasing of switch element 403, etc.) and the type of temperature variable element 421 (e.g., negative temperature variable element or positive temperature variable element) used in bypass system 400. Current flow through switch circuit 420 is supplied from a power source including battery 102 or a secondary power source 430 that is disconnected from battery 102. Secondary power source 430 may include a variety of different power sources, such as a DC power source, e.g., a DC / DC converter, a vehicle auxiliary battery, etc. Alternatively, current may be supplied to switch circuit 420 from battery 102.

[0049] In general, the further elements of switch circuit 420 are selected and arranged such that when temperature variable element 421 achieves a resistance that falls within the effective resistance range, the current flow through and / or the resistance of temperature variable element 421 causes switch circuit 420 to provide a signal to switch element 403 that causes transition of switch element 403.

[0050] For example, in bypass system 400 embodiments in which switch element 403 is controlled by switch circuit 420 via a voltage-based signal (e.g., the bypass system 400 embodiment of FIG. 4), switch circuit 420 optionally includes resistor 410 and / or other elements arranged in a voltage divider configuration. The voltage divider configuration varies the voltage supplied to gate 407 of semiconductor switch 405 in response to changes in the temperature of the core of temperature variable element 421 (and thus the resistance of temperature variable element 421). Thus, when temperature variable element 421 achieves a resistance that falls within the effective resistance range, the voltage signal supplied to gate 407 by switch circuit 420 corresponds to a voltage sufficient to effect a transition of semiconductor switch 405.

[0051] Referring to Figure 4, a bypass system 400 according to one exemplary embodiment is shown. As shown in Figure 4, the switch element 403 includes a solid-state semiconductor switch 405 that restricts or allows current flow based on a voltage applied to a gate 407 of the semiconductor switch 405 by a switch circuit 420. Non-limiting examples of the semiconductor switch 405 include, for example, a field effect transistor (FET), such as a junction field effect transistor (JFET), a metal oxide semiconductor field effect transistor (MOSFET), or other similar types of FETs that can operate as a switch based on an applied voltage.

[0052] 4, the switch circuit 420 embodiment shown in the bypass system 400 embodiment of FIG. 4 uses a voltage divider arrangement of a temperature variable element 421 including a negative temperature variable element in series with a fixed resistance resistor 410 to vary the voltage supplied to the semiconductor switch 405. Thus, when the resistance of the temperature variable element 421 reaches a level within the effective resistance range (e.g., in response to heat dissipated when a larger current is passed through the current-limiting element 104 during steady-state charging), the voltage supplied to the switch element 403 by the switch circuit 420 corresponds to a voltage that falls within a threshold voltage range configured to effect transition of the switch element 403, thus allowing current from the battery 102 to flow through the bypass path 401 to the load 108.

[0053] According to various embodiments, given the high power demands of electric vehicles ("EVs"), power system 10 is advantageously incorporated into an EV power distribution system. Referring to Figure 5, according to one exemplary embodiment, a high voltage power circuit 500 is shown that utilizes power system 10 as described according to any embodiment above to supply current to one or more high voltage loads 512 (e.g., 48V loads), such as an EV's electromechanical anti-roll control system (EARC), electric turbo (E-Turbo), belt starter generator (BSG), etc.

[0054] A contactor 504 and / or current sensor 506 are optionally disposed in series with the EV's primary battery 502. The contactor 504 may include any electronic or electromechanical device that isolates the battery 502 from the rest of the circuit 500. For example, the contactor 504 is a relay, contactor, or other switch that can be manually or automatically configured to allow or prevent current flow to / from the battery 502. The contactor 504 is optionally controlled by a control circuit (not shown) to provide thermal, overvoltage, undervoltage, or other protection to the circuit 500. The contactor 504 may optionally be replaced (or supplemented) with a fuse or other protective device.

[0055] An optional current sensor 506 measures the current flow from / to the battery 502. The current sensor 506 may monitor the charge and discharge rates and other parameters that may affect the health or condition of the battery 502. In some embodiments, the current sensor 506 may also be connected to any control circuitry used to activate the contactor 504 based on the measured current flow from and to the battery 502.

[0056] An optional DC / DC converter 514 reduces the power provided by the battery 502 and / or supercapacitor 510. The reduced power may be used for lower demand elements 516 of the EV, such as headlights, power windows, a radio or other elements of the EV, and / or may be used to recharge a lower power battery 518 (e.g., a 12V battery).

[0057] The power system 10, including the charge system 100 and bypass system 400 described according to any embodiment herein, may be electrically connected to the battery 502 and supercapacitor 510 of the high-voltage power circuit 500 according to any number of different arrangements, configurations, etc. The power system 10 is optionally integrated into other elements of the EV. For example, in some embodiments, the power system 10 is integrated into the high-voltage power circuit 500 via a power pack system 600, as representatively shown in FIG. 6 .

[0058] 6 , according to some embodiments, the battery 502, the supercapacitor 510, and the power system 10 are combined into a hybrid power pack system 600. The battery cells 601 forming the battery 502 are housed within a first portion of the housing 610 (e.g., a first side of the interior cavity of the housing 610), and the capacitive element 603 forming the supercapacitor 510 is housed within a second portion of the housing 610 (e.g., a second side of the interior cavity of the housing 610). The electrical elements of the power system 10 may be combined into any of a variety of structures or configurations and supported relative to the power pack housing 610 such that the battery charging path 103 couples the battery cells 601 to a positive terminal 605 supported by the housing 610, and the capacitor charging path 105 couples the capacitive element 603 to the positive terminal 605. One or more of the battery cells 601 supported within the housing 610 are optionally used to power the switch circuit 420. Alternatively, a secondary power source 430 for powering the bypass system 400 is also supported by the power pack housing 610 .

[0059] In such embodiments, the hybrid power pack system 600 may be directly coupled to a load (e.g., high voltage load 512) without the need to connect or wire any additional elements to it. In some such embodiments, the power pack system 600 also optionally includes additional elements (e.g., contactors, fuses, etc.) that are also supported within the power pack housing 610.

[0060] The terms "about" and "approximately" as used herein will be understood by those of ordinary skill in the art and will vary to some extent depending on the context in which they are used. If there are any uses of these terms that are not clear to persons of ordinary skill in the art, taking into account the context in which it is used, "about" and "approximately" will mean up to ±10% of the particular term.

[0061] The use of the terms "a," "an," and "the" and similar referents in the context of describing elements (particularly in the context of the claims below) should be construed to encompass both the singular and the plural unless otherwise indicated herein or clearly contradicted by context. The recitation of numerical ranges herein is merely intended to serve as a shorthand method of referring individually to each individual value falling within the range, unless otherwise indicated herein, and each individual value is incorporated into the specification as if it were individually set forth herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context. The use of all examples or exemplary language (e.g., "such as") provided herein is intended merely to better describe embodiments and does not impose limitations on the scope of the claims unless otherwise stated. No language in the specification should be construed as indicating any non-claimed element as essential.

[0062] While particular embodiments have been illustrated and described, it is to be understood that changes and modifications may be made therein in accordance with ordinary skill in the art without departing from the technology in its broader aspects as defined in the following claims.

[0063] The embodiments illustratively described herein may suitably be practiced in the absence of any element or limitation not specifically disclosed herein. Thus, for example, terms such as "comprise," "include," and "contain" should be read broadly and without limitation. Additionally, the terms and expressions used herein are used as terms of description, not limitation, and the use of such terms and expressions is not intended to exclude any equivalents of the shown and described features or portions thereof, and it is recognized that various modifications are possible within the scope of the claimed technology. Additionally, the phrase "consisting essentially of" is understood to include the specifically described elements and additional elements that do not materially affect the basic and novel characteristics of the claimed technology. The phrase "consisting of" excludes any unspecified elements.

[0064] The present disclosure should not be limited with respect to the particular embodiments described in this application. It will be apparent to those skilled in the art that numerous modifications and variations can be made without departing from the spirit and scope thereof. Functionally equivalent methods and compositions within the scope of the present disclosure, in addition to those described herein, will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are deemed to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that the present disclosure is not limited to particular methods, reagents, compounds, compositions or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting.

[0065] Additionally, when features or aspects of the disclosure are described in terms of a Markush group, those skilled in the art will understand that the disclosure is also described in terms of any individual member or subgroup of members of the Markush group.

[0066] As will be understood by those skilled in the art, for all purposes, especially in terms of providing a written description, all ranges disclosed herein also encompass all possible subranges and combinations of subranges. Any stated range can be easily recognized as fully describing and validating the same range divided into at least equal parts, such as 1 / 2, 1 / 3, 1 / 4, 1 / 5, 1 / 10, etc. As a non-limiting example, each range discussed herein can be easily divided into a lower 1 / 3, a middle 1 / 3, and an upper 1 / 3, etc. Also, as will be understood by those skilled in the art, all terms such as "up to," "at least," "greater than," "less than," etc., refer to a range that includes the stated numerical value and can then be divided into subranges as described above. Finally, as will be understood by those skilled in the art, a range includes each individual member.

[0067] Other aspects are set forth in the following claims.

Claims

1. 1. A power system for a vehicle, comprising: a battery charging path configured to provide current from the battery to a load, the battery charging path having a first end for electrical connection to a positive terminal of the battery and a second end for electrical connection to the load, and a capacitor charging path configured to provide current from the capacitor to the load, arranged in parallel with each other; a current limiting element having a variable resistance disposed in series along the battery charging path, the current limiting element having a first leg coupled to the positive terminal of the battery and a second leg coupled to a junction including the load and a terminal of the capacitor; 1. A bypass system comprising: a bypass path disposed between the positive terminal of the battery and the junction in parallel with the battery charging path; a switch element disposed along the bypass path and configured to selectively prevent and allow current flow along the bypass path; Switch circuit and Including, a bypass system, the switch circuit configured to prevent current flow along the bypass path while the current limiting element is defined by a resistor that substantially limits current flow between the battery and the load; and a contactor disposed between the positive terminal of the battery and the current limiting element, the contactor configured to control current flow from the remainder of the power system to the battery based on current measurements in the battery charging path; The power system.

2. 2. The power system of claim 1, wherein when a current limiting element is defined by a resistor that substantially limits current flow between the battery and the load, current flow between the battery and the load is less than current flow along a capacitor charging path.

3. 10. The power system of claim 1, wherein the switch circuit is configured to allow current flow along a bypass path while defining a current limiting element with a low resistance that allows current to flow between the battery and the load.

4. 4. The power system of claim 3, wherein when the switch circuit is activated to allow current flow along the bypass path, substantially no current flow occurs along the capacitor charging path between the capacitor and the load.

5. 10. The power system of claim 1, wherein the switch circuit includes a temperature variable element having a resistance that changes in response to a first change in temperature.

6. 6. The power system of claim 5, wherein the change in resistance is achieved without applying an external control input signal to the temperature variable element.

7. 6. The power system of claim 5, wherein the current-limiting element comprises a temperature sensitive element having a resistance that changes in response to a second change in temperature.

8. the temperature variable element includes a positive temperature coefficient thermistor and the temperature sensitive element includes a negative temperature coefficient thermistor; when the core of the temperature variable element reaches a predetermined temperature, the resistance of the temperature variable element increases in response; When the core of the temperature sensitive element reaches a predetermined temperature, the resistance of the temperature sensitive element decreases in response.

8. The power system of claim 7.

9. 6. The power system of claim 5, wherein the switching element comprises a semiconductor switch.

10. 10. The power system of claim 9, wherein a change in the resistance of the temperature variable element is configured to vary a voltage signal applied to a gate of the semiconductor switch.

11. the current limiting element includes a temperature sensitive element; a resistance of the temperature sensitive element decreases in response to the core of the temperature sensitive element reaching a temperature above a first threshold temperature range; 11. The power system of claim 10.

12. a voltage signal applied to a gate of the semiconductor switch is activated in response to the core of the temperature variable element reaching a temperature above a second threshold temperature range, thereby allowing current flow through the bypass path; the second threshold temperature range corresponds to a temperature higher than the temperature of the first threshold temperature range; 12. The power system of claim 11.

13. 13. The power system of claim 12, wherein the resistance of the temperature variable element increases in response to the temperature of the core of the temperature variable element exceeding a second threshold temperature range.

14. 11. The power system of claim 10, wherein the switch circuit further comprises a power source and a resistor disposed in series with the temperature variable element.

15. 11. The power system of claim 10, wherein the temperature variable element is physically coupled directly to the battery charging path.

16. a housing having a first portion configured to house a battery and a second portion configured to house a capacitor; and A power system supported by the housing.

1. A power pack assembly comprising: The power system comprises: a battery charging path extending between the first portion of the housing and a terminal supported by the housing, the path having a first end for electrical connection to the positive terminal of the battery and a second end for electrical connection to a load; a capacitor charging path extending between the second portion of the housing and the terminal, the capacitor charging path being disposed in parallel with the battery charging path; a current limiting element having a first leg coupled to the positive terminal of the battery and a second leg coupled to a junction including the load and a terminal of the capacitor, the current limiting element having a variable resistor disposed in series along the battery charging path; 1. A bypass system comprising: a bypass path disposed in parallel with the battery charging path and located between the positive terminal of the battery and the junction; a switch element disposed along the bypass path and configured to selectively restrict and allow current flow along the bypass path; a switch circuit configured to actuate the switch element to limit current flow along the bypass path; a bypass system including: a contactor disposed between the positive terminal of the battery and the current limiting element, the contactor configured to control current flow from the remainder of the power system to the battery based on current measurements in the battery charging path; The power pack assembly.

17. further comprising a battery and a capacitor; the battery is contained within the first portion of the housing and connected to the terminals by a battery charging path; the capacitor is contained within the second portion of the housing and is connected to the terminal by a capacitor charging path; 17. The power pack assembly of claim 16.

18. the switch circuit includes a temperature variable element having a variable resistance; the switch circuit is configured to actuate a switch element in response to a change in temperature of the core of the temperature variable element to selectively restrict and allow current flow along a bypass path; 17. The power pack assembly of claim 16.

19. causing current from the battery to flow through a current limiting element located along a battery charging path having a first end for electrical connection to a positive terminal of the battery and a second end for electrical connection to a load; allowing current to flow from a capacitor located in parallel with the current limiting element to the load, the current limiting element having a first leg coupled to the positive terminal of the battery and a second leg coupled to a junction including the load and a terminal of the capacitor; activating a switch circuit to cause a switch element to allow current to flow between the battery and the load along a bypass path disposed between the positive terminal of the battery and the junction and in parallel with the battery charging path; the switch circuit actuating the switch element to allow current to flow from the battery along the battery charging path to the battery while simultaneously allowing current flow between the battery and the load along the bypass path; and activating a contactor disposed between the positive terminal of the battery and the current limiting device, the contactor configured to control current flow from the remainder of the circuit to the battery based on a current measurement in the battery charging path.

12. A method for charging a load, comprising:

20. The current limiting element includes a temperature sensitive element and the switch circuit includes a temperature variable element; the switch circuit operates a switch element based on a change in resistance of the temperature variable element; a change in the resistance of the temperature variable element in response to the temperature of the core of the temperature variable element reaching a first temperature; the temperature sensitive element causes a current to flow along a battery charging path based on a decrease in resistance of the temperature sensitive element; a change in the resistance of the temperature sensitive element occurs in response to a core temperature of the temperature sensitive element reaching a second temperature; the core of the temperature variable element reaches the first temperature after current flow from the capacitor to the load stops; the core of the temperature sensitive element reaches the second temperature before current flow from the capacitor to the load stops.

20. The method of claim 19.

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