This application claims the benefit and priority of Chinese Patent Application Number 2012100103422 filed Jan. 13, 2012. The entire disclosure of the above application is incorporated herein by reference.
The present disclosure relates to temperature sensors and, more particularly, to a durable, flexible, low-profile temperature sensor probe.
This section provides background information related to the present disclosure which is not necessarily prior art.
In rechargeable energy storage systems, particularly those used in automotive vehicle applications, it is important to know the temperature of the batteries so that system performance can be optimized and conditions adverse to the system, such as charging the battery at low temperatures, can be avoided. Consequently, temperature sensors are used to sense the battery temperature during vehicle operation.
The battery pack is typically comprised of a plurality of individual power cells which are tightly packed together to minimize space. In this regard, one or more temperature sensors are provided in the battery. The temperature sensor probe preferably has a low profile and can be tightly integrated into the battery pack, sandwiched in between the cells, since space is at a premium in the vehicle. The temperature sensor probe preferably promotes good surface contact area with the object to be sensed to enable it to accurately and quickly sense the battery temperature.
Because multiple sensors are used for each battery pack, the sensor is preferably cost effective to manufacture.
Prior low-profile temperature sensor probe designs incorporated a thermistor comprising traces on a printed circuit board (PCB) coated with a insulating material and having a connector block attached at one end of the board. However, the prior designs did not prove reliable and were susceptible to damage. For example, the PCB is brittle and could not effectively and reliably withstand routine handling without damage. Additionally, the insulating coating did not provide adequate electrical insulation and effective isolation from ambient conditions like temperature and humidity.
As shown in the figures, the temperature sensor probe of the disclosure includes a probe circuit subassembly having a temperature sensing thermistor element that is overmolded with a durable insulating material to form the sensor probe body. The sensor probe body forms a connector block portion and a flexible extension portion. The thermistor element includes an NTC bead having a pair of bead lead wires that are electrically spliced to a pair of lead wires that are, in turn, connected to a pair of terminals. The bead lead wires are protected by a PTFE cover. The electrical splices between the bead lead wires and the lead wires are electrically isolated and protected by shrink wrap tubing that covers the entire electrical connection. The probe circuit subassembly is then overmolded with a durable, resilient plastic that encompasses the wires of the probe circuit subassembly to protect them and create the flexible extension portion. The flexible extension portion enables the sensor probe to conform to the surface of the object to be sensed without putting an undue a strain on the components of the probe circuit subassembly. The thermistor element remains exposed to contact with the object to be sensed. The connector block is configured to accommodate a plug-in-type electrical connector.
The temperature sensor probe and, particularly, its probe circuit subassembly, is fully insulated electrically, thermally and from other ambient conditions, such as humidity and dirt. The temperature sensor probe is durable yet exhibits flexibilty. The sensor provides an integral connector for connection to a wiring harness, controller, or the like. The low profile configuration of the temperature sensor probe makes it ideal for applications requiring a small space claim.
As shown in the Figures the temperature sensor probe assembly is suitable for use in measuring temperatures in a rechargeable energy storage system used in an automobile. The temperature sensor probe is flexible to allow for expansion and contraction of the cells and/or cell modules during operation, and to closely form to the surface of the cells and/or cell modules. At the same time, the sensor probe provides a robust means to electrically connect the sensor probe to a wiring harness and/or a control module or other electronics in the vehicle.
In one aspect, the disclosure provides a low-profile temperature sensor probe comprising a probe circuit encapsulated by an integral dielectric body that is molded over the probe circuit. The probe circuit comprises a thermistor element including a pair of insulated thermistor leads, a first protective tubular material surrounding both of the thermistor leads, and a pair of insulated lead wires having a first end and a second end, each lead wire electrically connected at the first end to a respective one of the thermistor leads, thereby creating two electrical splice connections between insulated thermistor leads and the insulated lead wires. In addition, a pair of terminals are included, and each lead wire is electrically connected at the second end to a respective one of the terminals. A first heat-shrinkable, dielectric tubular material surrounding one of the pair of electrical splice connections, the tubular material isolating the electrical splice connections from each other, and a second heat-shrinkable, dielectric tubular material surrounding both of the pair of electrical splice connections and the first tubular material are further included. The body comprises a connector block portion and an extension portion, the connector block portion housing the electric terminals and being configured to accommodate a plug-in type electrical connector, and the extension portion extending from a first end proximate to the connector block portion generally linearly along a longitudinal axis of the sensor probe to a second end distal from the connector block portion. Also, the thermistor element is exposed near the distal end of the extension portion to enable it to directly contact an object to be sensed for temperature by the sensor probe.
In other aspects, the extension portion further comprises an aperture near the distal end of the extension portion and the thermistor element is located in the aperture. Also, the low-profile temperature sensor probe includes a support cover installed in the aperture that forms at least a portion of a pocket surrounding the thermistor element and positions the thermistor element relative to a first side surface of the extension portion, for example, so that it slightly protrudes from the first side surface of the extension portion. In still other aspects, the low-profile temperature sensor probe body and support cover comprise a resilient thermoplastic material.
In another aspect, the disclosure provides a low-profile temperature sensor probe including a probe circuit substantially encompassed by an integral, resilient, dielectric body. The probe circuit comprises a thermistor having two first insulated lead wires, two second insulated lead wires, and a resilient protective cover located around the first insulated lead wires. Each first lead wires is electrically connected to a respective second lead wire to create two first lead wire/second lead wire connections. The first lead wire/second lead wire connections being electrically isolated from one another. The body has an extension portion that generally extends along a longitudinal axis of the sensor probe from a first proximal end to a second distal end, and the extension portion comprises a first surface and an aperture near its distal end. The thermistor is located in the aperture and positioned relative to the first surface such that it directly contacts an object to be sensed for temperature when the sensor probe is in use.
In yet another aspect, the disclosure provides a method for manufacturing a low-profile temperature sensor including providing a thermistor element having a thermistor bead and two insulated thermistor leads. The thermistor leads are surrounded with a tubular PTFE material. A pair of insulated lead wires is provided, each having a first end and a second end. Each thermistor lead is electrically connected to the first end of a corresponding lead wire to create a pair of first electrical connections. One thermistor lead/lead wire connection is surrounded with a first heat shrinkable, dielectric, tubular material, and the other thermistor lead/lead wire connection and the first heat shrinkable, dielectric, tubular material is surrounded with a second heat shrinkable, dielectric, tubular material. A pair of terminals are provided and each is electrically connected to a second end of a corresponding lead wire to create a pair of second electrical connections. The first and second electrical connections and the lead wires are encompassed with a dielectric, thermoplastic material to create a flexible extension portion including an aperture near a distal end of the extension portion with the thermistor element located within the aperture. A support element is inserted in the aperture to position the thermistor bead relative to a first surface of the extension portion such that the thermistor bead protrudes from the first surface.
In still another aspect, a method for manufacturing a low-profile temperature sensor with a circuit including a thermistor element and lead wires involves surrounding two insulated thermistor leads of the thermistor element with a protective, resilient material, then electrically connecting each of the two insulated thermistor leads of the thermistor element to a corresponding one of two lead wires to create two thermistor lead/lead wire connections. The thermistor lead/lead wire connections are electrically isolated from one another. Then, overmolding the thermistor lead/lead wire connections with a resilient, dielectric thermoplastic material to encompass thermistor lead/lead wire connections and forming a body having an extension portion including a first surface and an aperture in which the thermistor element is located. Finally, the thermistor element is positioned relative to the first surface such that the thermistor element protrudes from the first surface.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
As illustrated in the Figures, the disclosure provides a robust, compact, fast responding, fully insulated temperature sensor probe 10 with an integral connector block portion 12 and having a low profile. Because the sensor probe 10 has a low profile and small footprint, it is suitable for use in applications where space is at a premium. In one anticipated application, the sensor probe can be compressed between the battery cells in a battery pack of a rechargeable energy storage system.
The sensor probe 10 employs a fast-response-time, negative temperature coefficient (NTC) thermistor element 14. The thermistor element 14 is part of a probe circuit subassembly 16 that also includes insulated and covered lead wires 38, 40 and connection terminals 42. The probe circuit subassembly 16 is encapsulated in an integral dielectric housing or body 18 that is molded over the probe circuit subassembly 16. As shown, the thermistor element 14 nevertheless remains exposed at an end of the sensor probe 10 to enable it to directly contact an object to be sensed for temperature.
The overmolded dielectric body 18 of the sensor probe 10 makes the probe resilient, flexible and/or pliable to enable the sensor probe 10 to adapt to surface contours of the sensed object and to promote the direct contact between the sensor probe and the object to be sensed without creating undesirable strain on the probe circuit subassembly 16 or its components. In this regard, the sensor probe 10 can move or flex with the object while still maintaining good surface contact, such as in situations where the object expands and/or contracts with temperature changes.
One embodiment of the low profile temperature sensor probe 10 of the disclosure is illustrated in the figures. Referring to
The connector block portion 12 is configured to accommodate a plug-in type electrical connector, such as would be part of a standard wiring harness in an automobile or other application, for example, to connect the sensor probe 10 to a circuit for monitoring a condition of the sensor probe which is correlated to a temperature value. The connector block portion 12, therefore, houses the electric terminals 42 (best seen in
The flexible extension portion 20 of the sensor probe device 10 is shown to comprise a long, narrow, generally rectangularly-shaped feature. The extension portion 20 extends from a first end 22 proximate to the connector block portion 12 generally linearly along a longitudinal axis of the device to a second end 24 distal from the connector block portion 12. In the embodiment illustrated in the figures, the extension portion 20 has a first (front) side surface 26 and a second (back) side surface 28, and a plurality of apertures 30, 32 extending through the extension portion 20 from the first side surface 26 to the second side surface 28. The apertures 30, 32 can be operable to accommodate locating features and/or mounting fasteners (not shown) that can be used locate and/or secure the sensor probe device 10 in place when it is installed.
In addition to the locating or mounting apertures 30, 32, the extension portion includes an aperture 34 near the distal end 24 of the extension portion 20 in which the thermistor element 14 is located. A support cover 56 (
The construction of the probe circuit subassembly 16 may be understood with reference to
As shown in
Finally, the pair of terminals 42 (see
Referring to
Referring to
The overmolding can be accomplished in a single molding operation or in multiple molding operations, as depicted in
As shown in
In particular, for example, as shown in
In the schematic illustrations of
In an alternative embodiment of the sensor probe 10 of the disclosure, the overmolded body 18 does not have to include an integral connector block portion 12. For example, a completed sensor probe 10 body 18 could be configured as shown in
In still another alternative embodiment of the sensor probe 10 of the disclosure, the sensor probe 10 does not require any terminals 42. Instead, the lead wires 40 of the sensor probe 10 are lengthened so they extend from the sensor probe's overmolded body 18. In such a case, the length of the lead wires 40 could vary as required for a particular wiring arrangement of the sensor probe. For example, the lead wires 40 could extend in length so they may be directly connected to a controller monitoring the condition of the sensor probe. Alternatively, the lead wires of one or more sensor probe(s) could be wired to a common connector for the sensor probe(s) and/or other electronic components of the apparatus in which the sensor probe is installed. Still further, the lead wires could, themselves, form part of a wiring harness.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Number | Date | Country | Kind |
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2012100103422 | Jan 2012 | CN | national |