Battery Jacket

Abstract

A direct current powered heating jacket utilizing a carbon fiber heating element that, when enveloping a lithium-ion battery or battery pack, will quickly warm the battery or battery pack in a cold environment to its optimal operating temperature, thereby allowing the maximum discharge rate of the battery pack, is disclosed. Specifically, a system comprising one or more layers of carbon fiber heating elements within a flexible “battery jacket” that can be placed on or wrapped around a lithium-ion battery or battery pack is disclosed. The battery jacket may be connected to a direct current power source and can be controlled by a central processing unit (“CPU”). When the lithium-ion battery itself is used as the DC power source, the battery becomes “self-warming” and the optimal operating temperature of the battery can be maintained without an external DC power source.

Claims

1. A device for warming one or more lithium-ion batteries, comprising: a heating jacket comprising a flexible carbon fiber heating element having a top layer of foldable polymeric material and a bottom layer of foldable polymeric material; a direct current power source connected to each of two ends of the carbon fiber heating element to provide direct current electrical power to the heating element; a central processing unit (“CPU”) connected to the direct current power source for controlling the electrical output of the power source to the heating element; a temperature sensor for determining the temperature of the one or more lithium-ion batteries to be warmed, wherein the temperature sensor Is connected to the CPU; wherein the flexible heating jacket is located over, around or in between the one or more lithium-ion batteries to be warmed.

2. The device of claim 1 wherein the direct current power source comprises a transformer for inverting AC electrical current to direct current.

3. The device of claim 1 wherein direct current is applied to the heating element by the CPU when the temperature sensor indicates that the temperature of the one or more lithium batteries is below a pre-selected lower temperature.

4. The device of claim 3 wherein the direct current applied to the heating element is discontinued by the CPU when the temperature sensor indicates that the temperature of the one or more lithium-ion batteries has reached a pre-selected higher temperature.

5. The device of claim 1 wherein the direct current power source comprises the one or more lithium-ion batteries to be warmed.

6. A method for warming one or more lithium-ion batteries, comprising: placing a heating jacket comprising a flexible carbon fiber heating element having a top layer of foldable polymeric material and a bottom layer of foldable polymeric material, over, around or in between the one or more lithium-ion batteries to be warmed; applying direct current electrical power to each of two ends of the carbon fiber heating element; monitoring the internal temperature of the one or more lithium-ion batteries to be warmed; disconnecting the direct current electrical power to the carbon fiber heating element when the internal temperature of the one or more lithium-ion batteries to be warmed reaches a certain pre-selected upper temperature, as determined by a temperature sensor.

7. The method of claim 6 wherein the pre-selected upper temperature is 149° F.

8. The method of claim 6 wherein the application of direct current electrical power is controlled by a central processing unit.

9. The method of claim 6 wherein the direct current electrical power is applied when the temperature of the one or more lithium-ion batteries reaches a pre-selected lower temperature.

10. The method of claim 9 wherein the pre-selected lower temperature is 59° F. or below.

11. A device for maintaining the internal temperature of one or more lithium-ion batteries within a pre-determined temperature range, comprising: a heating jacket comprising a flexible carbon fiber heating element having a top layer of foldable polymeric material and a bottom layer of foldable polymeric material, located over, around or in between the one or more lithium-ion batteries; a temperature sensor for determining the internal temperature of the one or more lithium-ion batteries, wherein the temperature sensor is connected to a central processing unit (“CPU”); a direct, current electrical power source connected to each of two ends of the carbon fiber heating element to provide direct current electrical power to the heating element; wherein the direct current electrical power is applied to the heating element by the CPU when the temperature sensor indicates that the internal temperature of the one or more lithium-ion batteries Is at or below a pre-determined lower temperature, and the direct current electrical power to the heating element is discontinued by the CPU when the internal temperature of the one or more lithium-ion batteries reaches a pre-determined upper temperature.

12. The device of claim 11 wherein the pre-determined lower temperature is about 59° F. and the pre-determined upper temperature is about 149° F.

13. The device of claim 11 wherein, the direct current electrical power source is the one or more lithium-ion batteries.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a diagrammatic view of an embodiment of this invention;

[0013] FIG. 2 is a view of an embodiment of this invention;

[0014] FIG. 3 is perspective view of an embodiment of this invention;

[0015] FIG. 4 is a top view of a further embodiment of the invention; and

[0016] FIG. 5 is a diagrammatic view of a further embodiment of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The preferred embodiments of the present invention will now be described with reference to the FIGS. 1-5 of the drawings. Identical elements in the various figures are designated with the same reference numerals.

[0018] FIGS. 1 and 2 illustrate a preferred embodiment of the device of the present invention, generally designated by the reference number 100. The device comprises a flexible carbon fiber heating element 110 enclosed in a flexible, foldable polymer covering 120 which, together with heating element 110, forms what is herein referred to as “battery jacket” 130. FIG. 1 also illustrates by schematic diagram electronic circuitry 140 that regulates the DC flow to heating element 110. The electronic components comprising electronic circuitry 140 are known to those of skill in the art as identified in FIG. 1.

[0019] FIG. 2 illustrates battery jacket 130, where it is shown that heating element 110 is encased in a flexible polymeric covering 120, much in the form of a laminate (see inset FIG. 3). Referring to FIG. 2, the flexible carbon fiber heating element 110 is comprised of conductive carbon fiber material that has resistivity to electrical current. The resistivity characteristic is such that, when DC electrical current is applied, heating element 110 will rapidly warm to a desired temperature with only a minimum of current. Although heating element 110 is illustrated as being generally flat, it may be of any desired cross-sectional shape, such as round or oval for examples. Heating element 110 also has a width and a thickness dimension which can vary according to the size of battery jacket 130 itself. Utilizing a wider heating element 110 provides for more surface area for contacting the lithium-ion battery and thus more efficient heating of the battery. When considering the width and thickness of heating element 110, it must be considered that heating jacket 130 and therefore heating element 110 are meant to be flexible for wrapping around a lithium-ion battery. Heating element 110 also comprises two terminal ends 180 for connecting to the DC current provide through electronic circuitry 140.

[0020] A cross-sectional view of battery jacket 130, (see inset FIG. 3), illustrates carbon fiber heating element 110 enclosed between a polymer top layer 160 and a polymer bottom layer 170.

[0021] FIG. 3 illustrates battery jacket 130 as folded between three lithium-ion batteries (not numbered), in the form of a battery pack. The flexible nature of carbon fiber heating element 110 and the polymer layers 160, 170 provides battery jacket 130 with the capability of completely surrounding one of the lithium-ion batteries, while the other two lithium-ion batteries are placed above and below battery jacket 130. In this manner, all three lithium-ion batteries are warmed simultaneously. Furthermore, other configurations using battery jacket 130, such as completely surrounding a lithium-ion battery to be warmed on all sides is contemplated by the within invention.

[0022] FIG. 4 illustrates another view of a lithium-ion battery being warmed by battery jacket 130 of the within invention. In this embodiment, battery jacket 130 is shown placed below a single lithium-ion battery. However, because of the flexibility of battery jacket 130, it can also wrap around the battery, as it does for the middle battery shown in FIG. 3.

[0023] FIG. 5 diagrammatically depicts a device for warming a lithium-ion battery, within the scope of this invention. The DC voltage from DC power source 190 is provided through electronic circuitry 140 to battery jacket 130. Central processing unit 200, which also controls other elements and functions of the device, is connected to power source 190 and regulates the DC voltage therefrom, including turning the voltage on and off as desired. An embodiment of this invention may also include a temperature sensor 210, connected to CPU 200, for monitoring the temperature of the lithium-ion battery. When the temperature of the lithium-ion battery falls below a pre-determined, pre-set temperature set in CPU 200, DC voltage is applied to heating element 110 in battery jacket 130, causing it to warm. When the temperature of the lithium-ion battery consequently reaches a pre-set maximum temperature set in CPU 200, CPU 200 signals power source 190 to discontinue the applied DC voltage. The lithium-ion battery temperature range in which the DC voltage is applied can be any range desired, narrow or large, but should be selected according to the ideal operational parameters of the lithium-ion battery. In a preferred embodiment of the invention, the lower temperature for pre-heating the lithium-ion battery is set at 59° F., and the upper shut-off temperature is set for 149° F., to protect the lithium-ion battery from being over heated.

[0024] Also, the lithium-ion battery itself may be connected to power source 190 and can become the source for the DC voltage for heating element 130. In this configuration, the lithium-ion battery becomes self-warming such that it is capable of maintaining its operational temperature for a period of time, while using only a minimum of electrical energy.

[0025] The preceding preferred embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those of skill in the art, or disclosed herein, may be employed without departing from the spirit of the invention or the scope of the claims.