Energy storage with heater

Abstract

An energy storage system is disclosed that includes a battery pack; an energy input connected to the battery pack for receiving energy from an energy source unit; an energy output connected to the battery pack for powering an energy consumption unit; at least one heater in thermal communication with the battery and the energy source unit, the heater adapted to heat the battery by: obtaining heat, from the energy source unit; and upon failure to obtain energy from the energy source unit, from the battery back; a temperature sensor for reading the temperature of the battery; and a controller in communication with the heater and the temperature sensor. A thermally conductive and moisture resistant encapsulant, encapsulates the battery pack.

Description

Energy Storage with HeaterTECHNICAL FIELD

[0001] The specification relates to energy storage systems generally, and in particular to rechargeable energy storage or batteries with heater.BACKGROUND

[0002] Sustainable ways of generating and consuming energy in an environmentally friendly manner are now widely being adopted to mitigate the impact of dependence on fossil fuels.

[0003] Rechargeable power sources, particularly in the form of lithium-ion batteries which were first commercialized in the early 1990s have accelerated the adoption of sustainably energy consumption for many small and large devices. The use of lithium-ion batteries in portable devices such as tablets, laptops, smart phones and the like, is now very common.

[0004] The advent of electric vehicles, and energy storage needs for solar power energy generation, have increased the scope and scale of adoption for rechargeable battery technologies. In particular, the use of rechargeable batteries has expanded into many new areas of application beyond indoor handheld devices, to include many outdoor implementations.

[0005] With the increasing use and improving capability of rechargeable battery packs, there is a shift in the mix of energy consumption and storage. The demand for rechargeable batteries that can operate in a wide range of environmental conditions is thus becoming increasing apparent.

[0006] Although, progress has been made in ensuring the operability of battery packs under different environmental conditions, improvements are desired.SUMMARY OF THE DISCLOSURE

[0007] In accordance with one aspect of the present disclosure, there is provided an energy storage system comprising: a battery pack comprising an energy input on the battery pack for receiving energy from an energy source unit; and an energy output for powering an energy consumption unit; a first temperature sensor for measuring temperature of the battery pack to obtain a battery temperature reading (TBATTERY) ; a first heater in thermal communication with the battery pack; a controller in communication with the first heater and the first temperature sensor, the controller operable to cause the first heater to heat the battery pack, using ordered steps of: (i) obtaining heat from the energy source unit when energy available at the energy source unit is above a threshold; and (ii) obtaining heat from the battery pack, otherwise, wherein a thermally conductive and moisture resistant encapsulant, encapsulates the battery pack thereby ensuring uniformity of temperature readings across the battery pack; and wherein upon the battery temperature reading being less than a first threshold (Theat), so that TBATTERY < Theat, the controller causes the first heater to heat the battery pack.

[0008] In accordance with one aspect of the present disclosure, the above system further comprises the property that: upon the battery temperature reading exceeding a second threshold (TMAX), SO that TBATTERY > TMAX, the controller is further adapted to stop the first heater from heating the battery pack, the second threshold being greater than the first threshold.

[0009] In accordance with one aspect of the present disclosure, the above system further comprises the property that wherein upon the battery temperature reading not being less than a third threshold (Tcharge), the controller is further adapted to charge the battery pack using the energy source unit but not otherwise.

[0010] In accordance with one aspect of the present disclosure, the above system further comprises: (a) a printed circuit board (PCB) on which the first heater is formed; (b) a second temperature sensor for measuring temperature of the PCB to obtain a PCB temperature reading (TPCB) ; (C) a second heater for heating one of the energy source unit and the battery pack; wherein the controller is further in communication with the second temperature sensor and the second heater; and wherein upon the PCB temperature reading exceedinga fourth threshold TPCB_MAX, the controller causes the first heater to stop heating the battery pack.

[0011] Other technical advantages may become readily apparent to one of ordinary skill in the art after review of the following figures and description.BRIEF DESCRIPTIONS OF THE DRAWINGS

[0012] For a better understanding of the embodiments described herein and to show more clearly how the embodiments may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which:

[0013] FIG. 1 is a perspective diagram of an exemplary embodiment of an energy storage system, in the form of a solar panel powered light fixture, in which both the solar panel and the light are capable of rotating 360 degrees independently;

[0014] FIG. 2 a schematic block diagram of several hardware modules of a general energy storage system, exemplary of an embodiment of the present disclosure, of which the energy storage system of FIG. 1 is an example embodiment;

[0015] FIG. 3 a schematic block diagram of a heater having a control circuit, and a first, a second and a third heater sub-blocks for use the energy storage system of FIG. 2;

[0016] FIG. 4 a schematic block diagram depicting a plurality of heat generating elements in one exemplary embodiment of the first heater sub-block of FIG. 3;

[0017] FIG. 5 a schematic block diagram depicting a plurality of heat generating elements in one exemplary embodiment of the second heater sub-block of FIG. 3;

[0018] FIG. 6 a schematic block diagram depicting a plurality of heat generating elements in one exemplary embodiment of the third heater sub-block of FIG. 3;

[0019] FIG. 7 is a plot of current versus voltage for the solar panel of FIG. 1 at a given irradiance;

[0020] FIG. 8 is a circuit diagram for implementing one or more blocks of the system ofFIG. 2.

[0021] FIG. 9 is a perspective view of a silicone encapsulant being poured into the energy storage system of FIG. 2;

[0022] FIG. 10 is a flowchart depicting an exemplary process for the operation the energy storage system of FIG. 2;

[0023] FIG. 11 is a schematic illustration of the various blocks and process steps for embodiments of the present disclosure; and

[0024] Unless otherwise specifically noted, articles depicted in the drawings are not necessarily drawn to scale.DETAILED DESCRIPTION

[0025] Directional terms such as "top," "bottom," "upwards," "downwards," "vertically," and "laterally" are used in the following description for the purpose of providing relative reference only, and are not intended to suggest any limitations on how any article is to be positioned during use, or to be mounted in an assembly or relative to an environment. The use of the word "a" or "an" when used herein in conjunction with the term "comprising" may mean "one," but it is also consistent with the meaning of "one or more," "at least one" and "one or more than one." Any element expressed in the singular form also encompasses its plural form. Any element expressed in the plural form also encompasses its singular form. The term "plurality" as used herein means more than one, for example, two or more, three or more, four or more, and the like.

[0026] In this disclosure, the terms "comprising", "having", "including", and "containing", and grammatical variations thereof, are inclusive or open-ended and do not exclude additional, un-recited elements and / or method steps. The term "consisting essentially of" when used herein in connection with a composition, use or method, denotes that additional elements, method steps or both additional elements and method steps may be present, but that these additions do not materially affect the manner in which the recited composition, method, or use functions. The term "consisting of" when used herein in connection with a composition, use, or method, excludes the presence of additional elements and / or method steps.

[0027] As used herein, the expression "energy storage system" refers to a system that can be charged by electricity generated from various sources including solar, wind, hydroelectric, or other sources of electricity and stores the received energy, and releases the stored energy as desired in suitable amounts for different end-uses including lighting, charging, power supplies, etc.

[0028] For clarity of illustration, where considered appropriate, reference numerals may be repeated among the Figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiment or embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the embodiments described herein. It should be understood at the outset that, although embodiments are illustrated in the figures and described below, the principles of the present disclosure may be implemented using any number of techniques, whether currently known or not. The present disclosure should in no way be limited to the implementations and techniques illustrated in the drawings and described in this disclosure.

[0029] Various terms used throughout the present description may be read and understood as follows, unless the context indicates otherwise: "or" as used throughout is inclusive, as though written "and / or"; singular articles and pronouns as used throughout include their plural forms, and vice versa; similarly, gendered pronouns include their counterpart pronouns so that pronouns should not be understood as limiting anything described herein to use, implementation, performance, etc. by a single gender; "exemplary" should be understood as "illustrative" or as a non-limiting example, and not necessarily as "preferred" over other embodiments. Further definitions for terms may be set out herein; these may apply to prior and subsequent instances of those terms, as will be understood from a reading of the present description. It will also be noted that the use of the term "a" or "an" will be understood to denote "at least one" in all instances unless explicitly stated otherwise or unless it would be understood to be obvious that it must mean "one".

[0030] Modifications, additions, or omissions may be made to the systems, apparatuses, and methods described herein without departing from the scope of the disclosure. Forexample, the components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses disclosed herein may be performed by more, fewer, or other components and the methods described may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order. As used in this document, "each" refers to each member of a set or each member of a subset of a set.

[0031] Disclosed herein is a system that, in one embodiment, includes an array of rechargeable batteries, or a battery pack in which the batteries are used to trickle heat themselves or using an energy source, by utilizing a heater in the form of an array of heat cables or interconnected heating elements which may include resistors and semiconductors.

[0032] The heating process is undertaken in order to operate and / or charge the batteries within a preferred or selected temperature range (e.g., between 2°C and 20°C). The selected range may be optimal in some sense such as battery performance, expected life of the energy storage system, or minimizing some other cost function.

[0033] FIG. 1 is a perspective diagram of an exemplary embodiment of an energy storage system, in the form of autonomous powered light fixture 100. The autonomous powered light fixture 100 incudes a lamp 106 powered by a solar panel 102. The solar panel 102 is attached to a housing 108 which is secured to a first pole section 104a. The first pole section 104a is rotatably attached onto a second pole section 104b by an attachment means 104c. The pole sections 104a, 104b and attachment means 104c are collectively referred to as pole 110. This configuration enables both the lamp 106 and the solar panel 102 to rotate 360 degrees independently.

[0034] The lamp 106 may be in the form of one or more printed circuit boards having a plurality of light emitting diodes (LEDs) mounted thereon that are in electrical communication with a power source. Other types of lamps may also be used. Pole section 104a, which is depicted as tubular, is rotatably mounted to pole section 104b by attachment means 104c which may be telescopic or any other means that permits independent rotation of the lamp 106 and the housing 108 including the solar panel 102. Many types of such attachments will be familiar to persons of skill in the art.

[0035] In the depicted embodiment, energy from the solar panel 102 is stored in a battery pack (not specifically illustrated in FIG. 1) which may be housed in the housing 108.

[0036] In other embodiments, other types of energy sources may also be used as will be described later. The battery pack is charged by the solar panel 102 during the day. The battery pack is configured to selectively provide heat at night or as needed based on temperature sensor readings and the desired battery operating temperature as will be described in more detail with reference to FIG. 2 below.

[0037] FIG. 2 depicts a simplified schematic block diagram of several hardware modules of an energy storage system 200. The system 200 includes an energy source 202 which may be a solar panel, wind turbine or another form of renewable energy source.

[0038] A housing 210 may be used to house an enclosure 204 that includes an energy storage element which may be in the form of a battery pack 220. The enclosure 204 may be filled with a thermal encapsulant such as silicone.

[0039] A heater 212 is in electrical communication with energy storage element in the form of a battery pack 220.

[0040] A first temperature sensor 216 and a second temperature sensor 208 are disposed in electrical communication with the battery pack 220. The second temperature sensor 208 is used to monitor the temperature proximate, at, or surrounding the energy source 202 which in this embodiment is a solar panel.

[0041] An energy consumption unit 206 which may be a light lamp (as shown in FIG. 1), or a handheld device such as a smartphone, tablet, digital media player, digital camera or camcorder, or some other device that is interconnected to draw energy from the battery pack 220 as needed.

[0042] The battery pack 220 may be made up of lithium iron phosphate battery (LiFePOi) batteries. In alternative embodiments, other chemistries such as lithium nickel manganese cobalt oxides. These may include LiNMC (Lithium Nickel Manganese Cobalt Oxide), LiNCA (Lithium Nickel Manganese Aluminium Oxide), LiMO (Lithium Manganese Oxide), LiCO (Lithium Cobalt Oxide) and lithium nickel manganese cobalt oxides having the general formula LiNixMnyCoi-x-yO2. In other embodiments, salt batteries may be used.

[0043] A control circuit 214 is in electrical communication with the first temperature senor 216 and the heater 212, as well as the battery pack 220. A Maximum Power Point Tracking (MPPT) circuit 226 may be formed as part of the control circuit 214 or in the heater 212 and can be used to detect maximum power output from a solar panel to efficiently charge and / or heat the battery pack 220.

[0044] A thermal protection circuit 218, which may form part of the control circuit 214, uses its own independent temperature sensor 224. The protection temperature sensor 224 is typically disposed inside of the battery back 220. The thermal protection circuit 218 prevents overheating by shutting off the heater 212 when the associated temperature sensors (e.g., the temperature sensor 216) fail, leading to excessive temperatures inside the battery pack 220.

[0045] The heater 212, in the depicted embodiment, is a double heater that is schematically illustrated as having a first heater submodule 212a and a second heater submodule 212b. The heater submodule 212a of the heater 212 is configured to take power from the solar panel (or other energy source 202) to heat the battery pack 220 initially using the energy source 202 when power is available. Additionally, the heater submodule 212b of the heater 212 will draw power from the battery pack 220 itself, when no other power source (such as the solar panel) is available.

[0046] FIG. 3 a schematic block diagram of a printed circuit board (PCB) that includes one embodiment of the heater control circuit 214 and a first, a second, and a third heater sub-blocks 212a, 212b, and 212c respectively, forming part of heater 212 for use the energy storage system 200.

[0047] The first heater sub-block 212a may be formed from a plurality of heat generating elements in the form of resistors, semiconductors, or combinations thereof. In the embodiment of the first heater sub-block 212a depicted in FIG. 4 the plurality of heat generating elements are resistors.

[0048] Similarly, the second heater sub-block 212b may be formed as a network of a plurality of heat generating elements in the form resistors, semiconductors or combinations thereof. In the embodiment of the second heater sub-block 212b depicted in FIG. 5 the plurality of heat generating elements are resistors.

[0049] The third heater sub-block 212c may be formed as a network of a plurality of heat generating elements in one exemplary embodiment of the third heater sub-block 212c of FIG. 3. In the embodiment of the third heater sub-block 212c depicted in FIG. 6, the plurality of heat generating elements are resistors.

[0050] In alternate embodiments, instead of the purely resistive network of heating elements shown in FIG. 4, FIG. 5, and FIG. 6, one or more of specific heat generating semiconductor chips, resistors, other impedance elements, or a combination of resistors and heat generating semiconductor chips may be used. The heat generating elements may include MOSFETs (metal-oxide-semiconductor field-effect transistors), and bipolar junction transistors (BJT) including both NPN transistors and PNP transistors. One specific semiconductor that may be used as a heat generating element is FJB102TM, which is an NPN high-voltage power Darlington transistor available from Fairchild Semiconductor International Inc., now part of ON Semiconductor Corporation.

[0051] In operation, in one embodiment, the battery pack 220 is charged by the energy source 202 in the form of the solar panel.

[0052] Temperature sensor 216 measures the temperature of the battery pack 220. When battery temperature as measured by temperature sensor 216 falls below a minimum threshold desired (e.g., below 2°C), then automatic heating of the battery pack 220 is initiated by the control circuit 214 and the heater 212.

[0053] An ambient light sensor 222 is depicted in FIG. 2. The ambient light sensor 222 in the depicted embodiment is a photodetector. The ambient light sensor 222 measures the amount of ambient light present in its surroundings and provides the control circuit 214 with a corresponding reading.

[0054] In some embodiments, the minimum threshold temperature required to start heating the battery pack 220 (Theat) may be the same temperature as the minimum threshold temperature for charging the battery back 220 (Tcharge) - e.g., 2°C.

[0055] In such cases where Tcharge = Theat (e.g., say 2°C), when the temperature reading T from the temperature sensor 216 falls below a minimum threshold temperature for charging (i.e., T < 2°C), then the control circuit 214 stops recharging the battery pack 220and simultaneously starts heating the battery pack 220. This will be discussed later with reference to FIG. 10.

[0056] In alternative embodiments, the temperature threshold for heating of the battery pack 220 (Theat) may be slightly higher than the temperature threshold for charging (Tcharge) the battery pack 220 (i.e., Theat > Tcharge) . This allows a charging operation that is already in progress to continue uninterrupted, if temperature of the battery pack starts to fall while charging, and allows system 200 to maintain the battery temperature above than 2°C. In other embodiments Tcharge may be set to 0°C so that no charging takes place while the battery temperature is below zero.

[0057] The energy consumption unit 206, which may be an LED light bulb or lamp in embodiments such as the lighting fixture 100, uses the battery pack 220 as a power source, to turn on automatically based on readings from ambient light sensor 222.

[0058] When the heater 212 takes power from the energy source 202 (e.g., a solar panel), the heater 212 maintains Maximum Power Point Tracking (MPPT) in such a way as to take maximum power from the energy source 202 (solar panel) to heat the battery pack 220.

[0059] As a solar panel such as solar panel 102 provides energy for a particular irradiation (e.g., 800 W / m2), its current (I) initially remains fairly constant while its voltage (V) increases up to a certain voltage. Thereafter there is a turning point, whereby as the voltage increases further, the current starts to decrease.

[0060] This is illustrated in FIG. 7 that depicts a plot of current (I) versus voltage (V) for a solar panel at a particular irradiation. As shown, the current I is relatively constant in the segment 702 of the plot but decreases rapidly at segment 706. As the power (P) is the product of the current and the voltage (i.e., P = IV), maximum power is generated at about point 704 when the current (I) starts to decrease. Therefore, the MPPT circuit 226 finds this point 704 to make sure that the power source (solar panel) is utilized at its highest power.

[0061] FIG. 8 depicts one embodiment of a detailed circuit diagram for the MPPT circuit 226. As shown, an integrated circuit comparator U3B detects solar panel voltage and determine if the voltage is at the inflection point 702 by sending a command to the NPN transistor QI and transistor Q2 through transistor MOSFET M2. Operational amplifier U7A senses the solar panel voltage through resistors R5 and R6. When voltage of the solar panelis going down (beyond the inflection point) it will reduce the drive of transistor QI and transistor Q2 but control its state. When the drive of transistor QI and transistor Q2 is lower it will reduce the current in the heater 212 which will tend to increase the voltage of the solar panel. As this feedback is sensed with capacitor C5 and resistor R4 will compensate and make the system stable.

[0062] The thermally conductive shielding material (silicone in this embodiment) encapsulates the battery pack to ensures uniformity of temperature readings across the battery pack 220. FIG. 9 depicts a perspective view of a silicone encapsulant 902 being poured into a housing 904 to encapsulate a battery pack. Accordingly, temperature readings by sensor 216 anywhere on the battery would be representative of the battery temperature across the entire battery back 220 and are unlikely to provide incorrect readings from any atypically hot or atypically cold spots with unrepresentative temperature that may come into contact with probes of sensor 216. As persons of skill in the art may realize, in the absence of an encapsulant with good thermal conductivity, incorrect readings may occur as a result of unrepresentative spots being measured, or from uneven distribution of heat.

[0063] In one embodiment, the system 200 may also heat the energy source 202 itself, when the temperature read by an associated sensor 208 falls below a threshold and the reading from ambient light sensor 222 indicates that adequate sunlight is present. This is especially useful in embodiments where the energy source 202 is a solar panel and the system 200 is operated in winter conditions. The heater 212 may be used to heat the solar panel to melt snow that may be covering the solar panel thereby exposing the panel to direct sunlight and increasing the energy generated by the solar panel.

[0064] In one alternative embodiment of the present invention, the temperature inside and in the middle of the batteries is measured. The heater 212 in this specific embodiment is made of a flexible printed circuit board (PCB) that is wrapped around the battery back. Since the PCB is flexible it will be able to wrap all around the battery.

[0065] FIG. 10 is a simplified flowchart summarizing steps in a process 800 that operates the system 200 of FIG. 2, the autonomous powered fixture 100 of FIG. 1, or other type of energy consuming unit 206 such as a camera, a tablet, or the like.

[0066] As illustrated, at step 802, the process 800 obtains the battery temperature TBATTERY and a PCB temperature TPCB from sensor 216 and another sensor such as sensor 224 respectively.

[0067] At step the temperature reading TBATTERY is compared (step 804) to the minimum threshold Theat to start heating the battery back (e.g. 2 °C). If TBATTERY is below the threshold Theat then the process starts the battery heater such as heater 212.

[0068] Otherwise, the system checks if the temperature reading TBATTERY is below the charging threshold Tcharge (step 808). As noted above, the thresholds Theat and Tcharge may be set to the same threshold value (e.g. 2°C).

[0069] If the temperature reading TBATTERY is not below the charging temperature, the process charges the battery as needed (step 810) and stops charging as needed (step 812) but otherwise temperature reading TBATTERY is below the charging temperature the process proceeds to step 818.

[0070] At step 818, the temperature reading TBATTERY is compared to the maximum threshold TMAX (e.g., 20 °C) and if TBATTERY > TMAX, then the process then shuts down the heater (step 814). A check is made to see if the PCB temperature reading exceeds the maximum TPCB_MAX (e.g., 80 °C) and if so (step 820), the process shuts down all heaters. Otherwise, the process continues back at step 802 of FIG. 10.

[0071] Another schematic illustration of the various blocks and process steps is shown in FIG. 11. The PCB temperature measurement may be obtained from sensor 218. Several battery temperature measurements are taken to operate the battery between 2°C and 20°C as well as turning off heating if the temperature exceeds predetermined maximum temperature thresholds. For example, battery temperatures exceeding 40°C and PCB temperatures exceeding 80°C cause heaters to be turned off. The power optimizer block implements Maximum Power Point Tracking (MPPT) circuit discussed above to utilize the maximum power from the solar panel.

[0072] At block 1102, a battery temperature TBATTERYI is measured. If the battery temperature TBATTERYI is less than a predetermined threshold TBATTERY_MIN (e.g., TBATTERYI < 2°C), then recharging of the battery is stopped (block 1112) and the heater is started (block 1110) by switching on a first switch 1116 that starts a battery heater 1114.

[0073] Otherwise, if the temperature TBATTERYI is less than another predetermined threshold (< 20 °C) and the battery is fully charged (block 1106) then the power optimizer (block 1108) is started. As shown the power optimizer (block 1108) controls a second switch 1134 that can start a second heater 1132 to heat the solar panel via a solar panel optimizer 1136.

[0074] Simultaneously, temperature is continually monitored so that PCB temperature is measured (block 1120) and a second battery temperature TBATTERYZ is measured (block 1122). If the PCB temperature TPCB is greater than a threshold TPCB-MAX (e.g., TPCB > 80 °C) then battery heater 1114 and solar panel heater 1132 are both turned off (block 1128) using switches 1116 and 1114 respectively. If the second battery temperature TBATTERYZ is above a battery threshold TBATTERY-MAX (e.g., TBATTERY2 > 40°C) then the protection circuit turns of all the heaters, by switching off switch 1118 which cuts off connection to electrical ground for both the battery heater 1114 and the solar panel heater 1132.

[0075] There are many advantageous features of embodiment of the present invention. For example, the use of silicone as an encapsulant is advantageous as silicone exhibits good thermal conductivity; acts as an electrical insulator; and provides a tight seal that shields the battery pack 220 and its interconnected electronic circuits from harsh outside environmental effects. In an enclosure that is properly sealed using a silicone encapsulant, no moisture or water can reach inside to cause deleterious effects on the battery pack or interconnected PCB and electronics. Silicone is also advantageous as it does not readily react with other chemical elements found inside the enclosure 204.

[0076] The light fixture embodiment of FIG. 1 allows the light lamp 106 and the solar panel 102 to be rotated 360 degrees independently which allows the light lamp 106 to be installed in the proper direction, for example on the side of a street, without any drilling in the pole 110 or any section thereof. It also allows the solar panel 102 to be orientated in a direction (e.g., south) to generate maximum power from the sun. The orientations of the solar panel 102 and light lamp 106 are completely independent.

[0077] There are many other advantages of embodiments of the present invention over the known systems. For example, US Patent No. 9,991,575 discloses a heater at the top of the battery which suffers from the disadvantage that as the temperature inside the battery will not typically be uniform or equally distributed. As the heat moves up in the air the bottom of the battery can be frozen while the top of the battery can be heated well abovethe trigger point. The thermal measurement is taken at the top which is not representative of the whole battery as there will be a gradient of temperature from bottom to top.

[0078] Similarly, US Patent No. 9,954,391 discloses at heater in the form of a heating wire or a heating sheet rather than discrete elements such as resistors and semiconductors. The temperature sensor is at the outer surface as opposed to the disclosed embodiments which place a temperature sensor inside the battery pack and utilize encapsulant to ensure accurate and representative reading of the battery temperature.

[0079] European Patent No 3066891 discloses the use stanyl to have better thermal uniformity across the batteries. Stanyl is a type plastic and prone to underperform due to moisture. Silicone is a much better material for outdoor applications as it is seals all the electronics (i.e., both heater and the battery) such that moisture cannot affect the circuit and lead to deterioration battery life. Moreover, stanyl is a hard material and can cause mechanical stress on the batteries due to thermal expansion. Silicone is a comparatively softer material and will not cause mechanical stress on the batteries.

[0080] WO 2017 / 031586 Al discloses a heater is made of an internal combustion engine and uses a heating rod which is a much less efficient solution that the solutions taught by embodiments of the present disclosure.

[0081] Although specific advantages have been enumerated above, various embodiments may include some, none, or all of the enumerated advantages.

[0082] Persons skilled in the art will appreciate that there are yet more alternative implementations and modifications possible, and that the above examples are only illustrations of one or more implementations. The scope, therefore, is only to be limited by the claims appended hereto and any amendments made thereto.

Claims

CLAIMSWhat is claimed is:

1. An energy storage system comprising:(a) a battery pack comprising an energy input on the battery pack for receiving energy from an energy source unit; and an energy output for powering an energy consumption unit;(b) a first temperature sensor for measuring temperature of the battery pack to obtain a battery temperature reading;(c) a first heater in thermal communication with the battery pack;(d) a controller in communication with the first heater and the first temperature sensor, the controller operable to cause the first heater to heat the battery pack, using ordered steps of:(i) obtaining heat from the energy source unit when energy available at the energy source unit is above a threshold; and(ii) obtaining heat from the battery pack, otherwise, wherein a thermally conductive and moisture resistant encapsulant, encapsulates the battery pack thereby ensuring uniformity of temperature readings across the battery pack; and wherein upon the battery temperature reading being less than a first threshold, the controller causes the first heater to heat the battery pack.

2. The system of claim 1, wherein upon the battery temperature reading exceeding a second threshold, the controller is further adapted to stop the first heater from heating the battery pack, the second threshold being greater than the first threshold.

3. The system of claim 1, wherein upon the battery temperature reading not being less than a third threshold, the controller is further adapted to charge the battery pack using the energy source unit but not otherwise.

4. The system of claim 2, wherein upon the battery temperature reading being less than the third threshold while the battery pack being charged, the controller is further adapted to stop charging the battery pack.

5. The system of claim 1, further comprising :(a) a printed circuit board (PCB) on which the first heater is formed,(b) a second temperature sensor for measuring temperature of the PCB to obtain a PCB temperature reading;(c) a second heater for heating one of the energy source unit and the battery pack; wherein the controller is further in communication with the second temperature sensor and the second heater; and wherein upon the PCB temperature reading exceeding a fourth threshold, the controller causes the first heater to stop heating the battery pack.

6. The system of claim 5, wherein upon the PCB temperature reading exceeding the fourth threshold, the controller also causes the second heater to turn off.

7. The system of claim 5, wherein the PCB is flexible and wraps around the battery pack thereby containing and spreading heat uniformly throughout the battery pack .

8. The system of claim 1, further comprising the energy source wherein the energy source comprises a solar panel.

9. The system of claim 1 wherein the battery pack comprises one or more lithium-ion batteries.

10. The system of claim 9, wherein the lithium-ion batteries comprise at least one of lithium iron phosphate (LiFePOi), LiNMC (Lithium Nickel Manganese Cobalt Oxide), LiNCA (Lithium Nickel Manganese Aluminium Oxide), LiMO (Lithium Manganese Oxide), LiCO (Lithium Cobalt Oxide) and lithium nickel manganese cobalt oxides having the general formula LiNixMnyCoi-x-yO2.

11. The system of claim 1, wherein the first threshold is 2°C.

12. The system of claim 2, wherein the second threshold is 40°C.

13. The system of claim 3, wherein the third threshold is 2°C.

14. The system of claim 6 wherein the fourth threshold is 80°C.

15. The system of claim 1, wherein the encapsulate comprises silicone.

16. The system of claim 15, wherein silicone encapsulation of the battery pack leads to said uniformity of temperature readings across the battery pack and provides protection against one or more of humidity, moisture, and deleterious environmental effects.

17. The system of claim 7, wherein the encapsulate comprises silicone and wherein silicone encapsulation of the battery pack and the flexible PCB having the first heater formed thereon lead to said uniformity of temperature readings across the battery pack and provide uniform heating of the battery pack.

18. The system of claim 5, wherein the energy storage system is an autonomous powered light fixture, and the energy consumption unit is a light lamp.

19. The system of claim 18, further comprising: a first pole section rotatably attached onto a second pole section, to enable both the lamp and the solar panel to rotate 360 degrees independently.

20. The system of claim 18, wherein the second heater heats the solar panel to so than any snow covering the solar panel melts, thereby exposing the solar panel to direct sunlight and increasing the energy generated by the solar panel.

1. The system of claim 18, further comprising a Maximum Power Point Tracking (MPPT) circuit in electrical communication with the solar panel, to generate maximum power from the solar panel at a given irradiance.

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