ACCUMULATOR WITH INTEGRATED TEMPERATURE SENSOR

Abstract

An accumulator comprises several stacked cells. Each cell includes an anode layer and a cathode layer separated by a permeable separator. At least one temperature sensor structure is arranged on the permeable separator between the anode and cathode layers of a first cell in the stack. The temperature sensor structure comprises at least a first material with which the permeable separator is partially coated, and a second material with which the permeable separator is partially coated. The first material overlaps the second material in an overlap region. A first sensor output terminal is connected to the first material, and a second sensor output terminal is connected to the second material. A voltage difference between the first and second sensor output terminals corresponds to the average temperature of the overlap region.

Description

INTRODUCTION

[0001] The subject matter of the disclosure relates to temperature monitoring systems for battery packs and, in particular, to an integrated temperature sensor for monitoring the same.

[0002] Vehicles, including electric vehicles and hybrid electric vehicles, incorporate power storage and distribution systems designed to store the electrical energy received during charging and distribute the stored electrical energy to the vehicle's systems during vehicle operation. One method for storing electrical energy is stacked battery cells.

[0003] Charging and discharging processes, as well as fluctuations in ambient temperature and heat from vehicle systems, can affect the temperature of the battery cells. The temperature of the battery cells can affect the efficiency of the battery. In addition, unexpected temperature changes can indicate faults or other undesirable processes.

[0004] Accordingly, it is desirable to provide an efficient and targeted system for monitoring battery temperatures within a stack of battery cells. SUMMARY

[0005] In an exemplary embodiment, a storage battery comprises a plurality of stacked cells, each cell comprising an anode layer and a cathode layer separated by a permeable separator, wherein at least one temperature sensor structure is arranged on the permeable separator between the anode layer and the cathode layer of a first cell of the stacked cells, wherein the temperature sensor structure comprises at least a first material with which the permeable separator is partially coated and a second material with which the permeable separator is partially coated, wherein the first material overlaps the second material in an overlap region,wherein a first sensor output terminal is connected to the first material and a second sensor output terminal is connected to the second material, and wherein a voltage difference between the first sensor output terminal and the second sensor output terminal corresponds to an average temperature of the overlap region.

[0006] In addition to one or more of the features described herein, the battery includes a plurality of temperature sensors, wherein each temperature sensor of the plurality of temperature sensors is arranged in a particular cell in the plurality of stacked cells.

[0007] In addition to one or more of the features described herein, the overlap region of each temperature sensor is located at the same coordinate position within each cell.

[0008] In addition to one or more of the features described herein, the overlap region of each temperature sensor is located at a specific coordinate position within each cell.

[0009] In addition to one or more of the features described herein, the first material has a layer thickness in the range of 50 nm to 500 nm, and the second material has a layer thickness in the range of 50 nm to 500 nm.

[0010] In addition to one or more of the features described herein, the first material is one of Cu and Cu-Ni alloy, Ni-Al alloy, Ni-Cr alloy, Fe, Ni-Si alloy, Pt, Pd, Pd rare earths, and ceramic material, and the second material is another of Cu and Cu-Ni alloy, Ni-Al alloy, Ni-Cr alloy, Fe, Ni-Si alloy, Pt, Pd, Pd rare earths, and ceramic material.

[0011] In addition to one or more of the features described herein, a metal foil contacts the first or second material, wherein the metal foil is either embedded in or disposed on the first or second material, and wherein the metal foil is a reference electrode.

[0012] In a further exemplary embodiment, a vehicle comprises a drive system with at least one electric motor, a battery system connected to the drive system via a power distribution system, wherein the battery system comprises at least a plurality of stacked cells, each cell in the plurality of stacked cells comprising an anode layer and a cathode layer separated by a permeable separator, wherein at least one temperature sensor structure is arranged on the permeable separator between the anode layer and the cathode layer of a first cell of the stacked cells, wherein the temperature sensor structure comprises at least a first material with which the permeable separator is partially coated, and a second material with which the permeable separator is partially coated, wherein the first material overlaps the second material in an overlap region,wherein a first sensor output terminal is connected to the first material and a second sensor output terminal is connected to the second material, and wherein a voltage difference between the first sensor output terminal and the second sensor output terminal corresponds to an average temperature of the overlap region, and a controller comprising at least one input connected to the first terminal and the second terminal, the controller being configured to convert a voltage difference between the first terminal and the second terminal into a temperature.

[0013] In addition to one or more of the features described herein, the at least one temperature sensing structure comprises a plurality of temperature sensing structures, wherein each temperature sensing structure of the plurality of temperature sensing structures is arranged in a particular cell in the plurality of stacked cells, and wherein the controller is configured to determine a temperature map of the plurality of stacked cells.

[0014] In addition to one or more of the features described herein, the overlap region of each temperature sensing structure is located at the same coordinate position within the corresponding cell as any other overlap region, and the temperature map of the plurality of stacked cells defines a temperature gradient along the plurality of stacked cells.

[0015] In addition to one or more of the features described herein, the overlap region of each temperature sensing structure is located at a different coordinate position within the corresponding cell than any other overlap region, and the temperature map of the plurality of stacked cells defines a distributed temperature map.

[0016] In addition to one or more of the features described herein, the first material has a layer thickness in the range of 50 nm to 500 nm, and the second material has a layer thickness in the range of 50 nm to 500 nm.

[0017] In addition to one or more of the features described herein, the first material is one of Cu and Cu-Ni alloy, Ni-Al alloy, Ni-Cr alloy, Fe, Ni-Si alloy, Pt, Pd, Pd rare earths, and ceramic material, and the second material is another of Cu and Cu-Ni alloy, Ni-Al alloy, Ni-Cr alloy, Fe, Ni-Si alloy, Pt, Pd, Pd rare earths, and ceramic material.

[0018] In addition to one or more of the features described herein, a metal foil contacts the first or second material, wherein the metal foil is either embedded in or disposed on the first or second material, and wherein the metal foil is a reference electrode.

[0019] In a further exemplary embodiment, a method for determining the temperature of a cell stack comprises providing at least a first voltage potential difference between a first output terminal and a second output terminal to a controller and converting the at least first voltage potential difference into a temperature using the controller, wherein the first sensor terminal and the second sensor output are components of a temperature sensing structure arranged on a permeable separator between an anode layer and a cathode layer of a first cell of a cell stack, wherein at least one temperature sensing structure is arranged on the permeable separator between the anode layer and the cathode layer of a first cell of the stacked cells, wherein the temperature sensing structure comprises at least a first material with which the permeable separator is partially coated, and a second material,with which the permeable separator is partially coated, wherein the first material overlaps the second material in an overlap region, wherein a first sensor output terminal is connected to the first material and a second sensor terminal is connected to the second material.,

[0020] In addition to one or more of the features described herein, providing at least the first voltage potential difference between the first sensor output terminal and the second sensor output terminal to the controller includes providing a plurality of voltage potential differences to the controller and converting each of the plurality of voltage potential differences into a plurality of temperatures, wherein each provided voltage potential difference corresponds to a particular temperature sensor within the stacked cell.

[0021] In addition to one or more of the features described herein, the method further comprises combining the plurality of temperatures into a gradient measurement of a cell temperature.

[0022] In addition to one or more of the features described herein, the method further comprises combining the plurality of temperatures into a point cloud measurement of a cell stack temperature.

[0023] In addition to one or more of the features described herein, the first material has a layer thickness in the range of 50 nm to 500 nm, and the second material has a layer thickness in the range of 50 nm to 500 nm.

[0024] In addition to one or more of the features described herein, the first material is one of Cu and Cu-Ni alloy, Ni-Al alloy, Ni-Cr alloy, Fe, Ni-Si alloy, Pt, Pd, Pd rare earths, and ceramic material, and the second material is another of Cu and Cu-Ni alloy, Ni-Al alloy, Ni-Cr alloy, Fe, Ni-Si alloy, Pt, Pd, Pd rare earths, and ceramic material.

[0025] The foregoing features and advantages, as well as other features and advantages of the disclosure, will be readily apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further features, advantages and details are listed only as examples in the following detailed description, which refers to the drawings in which: Fig. 1 shows a vehicle with an electric drive motor, Fig. 2 shows a battery cell according to an embodiment in a schematic representation, Fig. 3 shows a battery cell stack according to an embodiment in a schematic representation, Fig. 4 shows a temperature sensor separator for a battery cell in a detailed schematic representation, Fig. 5A shows a temperature sensor separator according to an example in a schematic representation, Fig. 5B shows a temperature sensor separator according to another example in a schematic representation, Fig. 5C shows a temperature sensor separator according to another example in a schematic representation and Fig. 5D shows a temperature sensor separator according to another example in a schematic representation. DETAILED DESCRIPTION

[0027] The following description is merely exemplary and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference characters designate like or corresponding parts and features. As used herein, the term module refers to a processing circuit, which may include an application-specific integrated circuit (ASIC), an electronic circuit, a processor (common, dedicated, or group), and memory executing one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the described functionality.As used herein, the term “controller” refers to any computer-based control system, including dedicated control systems, general vehicle controls, control programs distributed across multiple systems, or a similar control architecture.

[0028] According to an exemplary embodiment, a battery system for a vehicle comprises at least one battery with a set of stacked battery cells. A separator-like temperature sensor is placed between the electrode layers of a given cell without affecting cell operation. The temperature sensor enables the measurement of temperatures within the cell stack and can include targeted measurements at specific locations within the cell stack.

[0029] The temperature sensor comprises a two-layer thin-film coating with two selective materials on one side of a separator. The two selective materials overlap in an overlap region, and the voltage potential difference between the two materials, measured at the output terminals connected to each material, relates to temperature. The particular relationship and conversion between the voltage potential difference and the temperature of the cell depends on the known relationships between the selective materials used to form the sensor. A controller is connected to output terminals, with each output terminal in contact with only one of the selective materials. The voltage potential difference across the terminals is regressed using the known relationship to determine the average temperature in the overlap region.The size and location of the overlap area on the separator allows for precise targeting of the internal sensor measurements.

[0030] The temperature sensor (the combination of the material layers and the separator layer on which the materials are arranged) is porous and permeable and is placed within a cell stack. It can monitor the temperature from within the cell stack without disrupting cell operation. This sensor design provides flexibility, allowing measurements at various locations within the stack, and the measurement is not dependent on external probes or estimations.

[0031] With further reference to the general system described above, Fig. 1 shows an embodiment of a motor vehicle 10 with a battery system controller 24 configured to control a battery system. The vehicle 10 includes a vehicle body 12 that at least partially defines a passenger compartment 14. The vehicle body 12 also supports various vehicle subsystems, including a drive system 16, a battery system 22, other subsystems for supporting the functions of the drive system 16, and other vehicle components, such as a braking subsystem, a suspension system, a steering subsystem, a fuel injection subsystem, an exhaust subsystem, and the like.

[0032] The vehicle 10 may be an internal combustion engine vehicle, an electric vehicle (EV), or a hybrid vehicle. In one embodiment, the vehicle 10 is a hybrid vehicle that includes an internal combustion engine system 18 and at least one electric motor assembly. The drive system 16 includes, for example, a first electric motor 20 and a second electric motor 21. The motors 20 and 21 may be configured to drive wheels 23 on opposite sides of the vehicle 10. Any number of motors positioned at various additional locations on the vehicle 10 may be used to provide mechanical rotation for the corresponding systems and subsystems.

[0033] The battery system 22 may be electrically connected to the motors 20 and 21 and / or other components, such as the vehicle electronics. The battery system 22 may be configured as a rechargeable energy storage system (RESS) and include a plurality of compartmented battery cells. A battery system controller 24 is included within the battery system 22 and controls the charging and discharging functions of the batteries in the battery system 22. In alternative configurations, the battery system controller 24 may be a general vehicle controller remote from the battery system 22 and configured to control multiple systems and / or subsystems. The general vehicle controller may be located anywhere within the vehicle 10.In still further alternatives, the battery system controller 24 may be a distributed control system with multiple coordinating controllers throughout the vehicle 10, including controllers within the battery system 22 and controllers remote from the battery system 22.

[0034] In one embodiment, the battery system 22 includes one or more battery packs 28. The battery packs 28 include a plurality of individual battery cells arranged in a stack. In the exemplary system of Fig. 1 shows a simplified illustration of the power distribution bus 29, which supplies the drive systems 16 with power via an inverter 26.

[0035] With further reference to Fig. 1 illustrates Fig. 2 shows a simplified exemplary battery cell 100 as could be used in the battery system 24. The exemplary cell 100 includes an anode layer 110 and a cathode layer 120. A separator layer 130 is located between the anode and cathode layers 110, 120. The separator layer 130 is an electrically insulating material and includes a heat sensing structure having a first coating 162 disposed on a first side of the separator 130, a second coating 166 disposed on the first side of the separator 130, an overlap region 170 where the first coating 162 and the second coating 166 overlap, a tab 131 extending from the separator layer 130 and including portions of the first coating 162 and the second coating 164, and a pair of leads 132, 134 extending from the first coating 162 and the second coating 164, respectively.the second coating 164, with the leads 132, 134 supported by the tab 131. In some examples, the separator layer 130 may comprise another separator layer over the thermal sensor structure, the second separator layer being substantially identical to the separator layer 130 and the coating material of the separator layer 130 being between the separator layer 130 and the second separator layer. The separator layer 130 is thin enough (in the range of 10 µm to 50 µm) to be permeable and porous. Each coating material 162, 166 has a thickness in the range of 50 nm to 500 nm. The tab 131 extends beyond the peripheral edge of the separator layer 130. In alternative examples (see . Fig. 5B, Fig. 5C, Fig. 5D), each terminal 132, 134 may be located on separate tabs, resulting in two distinct tabs, each extending beyond the peripheral edge of the separator layer 130. While a practical implementation of the separator 130, the first coating layer 162, and the second coating layer 166 includes a third dimension of vertical thickness, for simplicity, the cell 100 may be considered a planar structure defined by an XY coordinate grid, with the peripheral edge being the edges in the XY plane.

[0036] Each accumulator within the accumulator system 22 consists of several accumulator cells 100. Fig. 3 shows an exemplary stack of three battery cells 200, each battery cell 200 comprising an anode layer 210 and a cathode layer 220, as in the exemplary battery cell 100 of Fig. 2. The battery cells 200 are stacked such that the cathode layer 220 of one battery cell 200 is adjacent to the anode layer 210 of the next battery cell 200, with a further separator 238 positioned between the battery cells 200. In the illustrated example, the separator layers 238 between the battery cells 200 do not include any temperature sensor structures. In each of the battery cells 200, there is a separator layer 230 with terminals 232, 234 arranged in the Fig. 2. In an alternative embodiment, the separator layer 230 may be used in addition to a conventional separator layer.

[0037] The terminals 232, 234 and the corresponding temperature sensor structure (in Fig. 2) may be included in each battery cell 200, it being understood that a practical implementation of a battery system 24 may include any number of cells 200, with a subset of the cells 200 including the temperature sensing structure. In such an example, the number of cells 200 including the temperature sensing structure is generally limited to the number of inputs available in a corresponding controller.

[0038] Fig. Figure 4 schematically shows a more detailed example of a temperature sensor structure as used in the accumulator cells 100, 200 of Fig. 2 and Fig. 3, including a top view and a partial cross-sectional view along cross section AA. A separator 330 comprises a porous permeable layer 332 that acts as a separator 130, 230 between the cathode layer 120, 220 and the anode layer 110, 210 of the respective cell 100, 300. Two tabs 342, 344 extend outwardly from the separator layer 332, and a corresponding output terminal 352, 354 is attached to each tab 342, 344. Each terminal 352, 354 is connected to inputs of a controller 356, and the controller 356 measures the voltage potential difference between the terminals 352, 354 and converts the difference into a temperature value.

[0039] A first coating layer 362 covering a first region 364 and a second coating layer 366 covering a second region 368 are disposed on the separator 330. The first region 364 and the second region include a common overlap region 370 in which the coating layers 362, 366 overlap and touch. The first coating layer 362 extends onto a first tab 342, and the second coating layer 366 extends onto the second tab 344. The terminals 352, 354 on each tab 342, 344 contact the corresponding coating layers 262, 266. The coating layers 362, 366 are made of different materials and, in one example, are selected from a Cu and Cu-Ni alloy, Ni-Al alloy, Ni-Cr alloy, Fe, Ni-Si alloy, Pt, Pd, Pd-rare earth, or ceramic-based materials. Each coating layer has a thickness 380 in the range of 50 nm to 500 nm.By using a thickness in the range of 50 nm to 500 nm, the coating layers 362, 366 do not reduce the porosity or permeability of the separator 330 and thus do not impair the energy storage and discharge functions of the cell 100, 200. In some examples, one or both of the coating layers 362, 366 may include a relatively small piece of metal foil 301, such as a lithium metal foil, deposited on or embedded in one of the coating layers 362, 366. The piece of metal foil 301 is connected to a lead 303 located on one of the tabs 342, 344 and is used as a reference electrode to provide a local voltage of the cathode layer 220 or the anode layer 210, respectively, for control in a known manner.

[0040] Due to the different materials of each layer 362, 366, a voltage potential difference exists between the two terminals 352, 354. The voltage potential difference depends on the average temperature in the overlap region 370. A controller 356 converts the voltage potential difference into a temperature measurement in the overlap region 370 and makes the temperature measurement(s) available to all other control programs, controllers, and / or vehicle systems that require or may use this information.

[0041] Since the voltage potential difference is the average temperature in the overlap region 370, it can be seen that depending on the positioning of the overlap region 370 within the cell 100, 200 different temperature measurements can be made. The examples in Fig. 5A, Fig. 5B, Fig. 5C and Fig. 5D illustrate example, non-limiting variations of the positioning and size (in percent of the separator 330) covered by the overlap region 370 according to some examples.

[0042] Fig. 5A illustrates an example in which the terminals 352, 354 are arranged on a common tab 342 / 344, with each terminal 352, 354 contacting only one of the coating layers. In the example of Fig. 5A, the overlap region 370 covers the entire separator 330 and represents an average temperature measurement of the entire cell 100, 200 in which the separator 330 is Fig. 5A is included. Fig. Figure 5B illustrates a similar example as Fig. 5A, however, each of the terminals 352, 354 is attached to a separate tab 342, 344 and the corresponding coating layers cover the entirety of the tabs 342, 344.

[0043] Fig. 5C provides an example with two tabs 342, 344, each tab 342, 344 supporting a terminal 352, 354. The coating layers 362, 366 together cover less than 50% of the separator 330, with each layer 362, 366 covering less than 30% of the surface. The overlap region 370 is located in the center of the separator 330 and produces a spot temperature reading at the center of the separator 330. It is further understood that similar spot readings can be produced in similar designs by placing the overlap region 370 at any point in the cell 100, 200 where a temperature reading is desired.

[0044] The inclusion of multiple separators 330 within a battery system 24 or multiple separators 330 within a single battery cell 100, 200 where the overlap regions 370 are located at different locations is used in some examples to provide a point map of temperature variations across the battery cell 100, 200 or the battery system 24.

[0045] Fig. 5D illustrates an example in which the overlap region 370 extends along an entire edge of the separator 330 and is otherwise constructed similarly to the example of Fig. 5C.

[0046] It should be noted that in some examples, a single battery system 24 or a single battery cell 100, 200 may utilize all or some of the illustrated variations, and the variations are not mutually exclusive within a single battery. It should also be noted that several different separators, similar to those described in Fig. 5A, Fig. 5B, Fig. 5C and Fig. 5D, can be used in combination and in conjunction with each other to generate a three-dimensional grid or array of temperature measurements that can be converted by the controller into a gradient measurement across the individual cell 100, 200 or across an entire cell stack.

[0047] The terms "a", "an" and "another" do not imply a limitation of quantity, but rather indicate the presence of at least one of the recited elements. The term "or" means "and / or" unless the context clearly indicates otherwise. Reference throughout this specification to "an aspect" means that a particular element (e.g., a feature, structure, step, or property) described in connection with the aspect is included in at least one of the aspects described herein and may or may not be present in other aspects. It is understood that the described elements in the various aspects may be combined in any suitable way.

[0048] When an element such as a layer, film, region, or substrate is described as lying "on" another element, it may lie directly on top of the other element, or there may be intervening elements. In contrast, when an element is described as lying "directly on" another element, there are no intervening elements.

[0049] Unless otherwise indicated herein, all examination standards are the most recent standard in effect as of the filing date of this application or, if priority is claimed, as of the filing date of the earliest priority application in which the examination standard appears.

[0050] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0051] While the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalent elements may be substituted without departing from the scope of the disclosure. Furthermore, many changes may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its essential scope. Therefore, the present disclosure is not intended to be limited to the particular embodiments disclosed, but is intended to include all embodiments falling within its scope.

Claims

[1] Accumulator, comprising: a plurality of stacked cells, each cell comprising an anode layer and a cathode layer separated by a permeable separator, at least one temperature sensor structure arranged on the permeable separator between the anode layer and the cathode layer of a first cell of the stacked cells, wherein the temperature sensor structure comprises at least a first material with which the permeable separator is partially coated and a second material with which the permeable separator is partially coated, wherein the first material overlaps the second material in an overlap region, wherein a first sensor output terminal is connected to the first material and a second sensor terminal is connected to the second material, and wherein a voltage difference between the first sensor output terminal and the second sensor output terminal corresponds to an average temperature of the overlap region. [2] The accumulator according to claim 1, wherein the accumulator comprises a plurality of temperature sensors, each temperature sensor of the plurality of temperature sensors being arranged in a particular cell in the plurality of stacked cells. [3] The accumulator of claim 2, wherein the overlap region of each temperature sensor is located at the same coordinate position within each cell. [4] The accumulator of claim 2, wherein the overlap region of each temperature sensor is located at a specific coordinate position within each cell. [5] The accumulator according to claim 1, wherein the first material has a layer thickness in the range of 50 nm to 500 nm and the second material has a layer thickness in the range of 50 nm to 500 nm. [6] The accumulator according to claim 1, wherein the first material is one of Cu and Cu-Ni alloy, Ni-Al alloy, Ni-Cr alloy, Fe, Ni-Si alloy, Pt, Pd, Pd rare earths and ceramic material and the second material is another of Cu and Cu-Ni alloy, Ni-Al alloy, Ni-Cr alloy, Fe, Ni-Si alloy, Pt, Pd, Pd rare earths and ceramic material. [7] The accumulator of claim 1, further comprising a metal foil contacting the first or second material, the metal foil being either embedded in or disposed on the first or second material, and the metal foil being a reference electrode. [8] Vehicle comprising: a drive system with at least one electric motor, an accumulator system connected to the drive system via a power distribution system, the accumulator system comprising at least a plurality of stacked cells according to one of claims 1 to 7. [9] A method for determining the temperature of a cell stack, comprising: Providing at least a first voltage potential difference between a first output terminal and a second output terminal to a controller and converting the at least first voltage potential difference into a temperature using the controller, wherein the first sensor terminal and the second sensor output are components of a temperature sensing structure arranged on a permeable separator between an anode layer and a cathode layer of a first cell of a cell stack, wherein at least one temperature sensing structure is arranged on the permeable separator between the anode layer and the cathode layer of a first cell of the stacked cells, wherein the temperature sensing structure comprises at least a first material with which the permeable separator is partially coated and a second material with which the permeable separator is partially coated,wherein the first material overlaps the second material in an overlap region, wherein a first sensor output terminal is connected to the first material and a second sensor terminal is connected to the second material., [10] The method of claim 9, wherein providing at least the first voltage potential difference between the first sensor output terminal and the second sensor output terminal to the controller comprises providing a plurality of voltage potential differences to the controller and converting each of the plurality of voltage potential differences into a plurality of temperatures, each provided voltage potential difference corresponding to a particular temperature sensor within the stacked cell.

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