Magnetic dilatometer for measuring expansion of individual electrodes

Abstract

The invention relates to a magnetic dilatometer for measuring the expansion of individual electrodes. A dilatometer for measuring battery expansion includes: a battery cell having a first electrode and a second electrode; an internal magnetic sensing element; and a magnetic sensor. The internal magnetic sensing element is configured to move in response to expansion of the first electrode during expansion of the battery cell and remain stationary in response to expansion of the second electrode. The magnetic sensor is stationary relative to the battery cell and is configured to sense a change in magnetic force intensity between the internal magnetic sensing element and the magnetic sensor. A controller is configured to measure an expansion of the first electrode independently of an expansion of the second electrode based on a change in magnetic force intensity between the internal magnetic sensing element and the magnetic sensor.

Description

Background Art

[0001] The information provided in this section is for the purpose of generally presenting the environment of the present disclosure. To the extent that work of the presently named inventors is described in this section and aspects that may not have been eligible as prior art at the time of filing are not explicitly or implicitly admitted as prior art against the present disclosure.

[0002] The present disclosure relates to systems and methods for measuring battery swelling, and more particularly to systems and methods for measuring the swelling of individual battery electrodes.

[0003] A battery pack includes one or more battery modules, each battery module including a plurality of battery elements. When the battery is charged and discharged, the battery elements experience swelling. When the battery elements are charged and discharged, chemical reactions within the battery elements cause the anode or cathode electrodes to expand or swell and contract. Monitoring the swelling of the battery elements helps to avoid electrode drying, improve battery element life, plan battery elements, estimate energy density, and / or design battery modules and battery packs. Summary of the Invention

[0004] The present disclosure provides a dilatometer for measuring battery swelling, the dilatometer including: a battery element having a first electrode and a second electrode; an internal magnetic sensing element; and a magnetic force sensor. The internal magnetic sensing element is configured to move in response to the expansion of the first electrode and remain stationary in response to the expansion of the second electrode during the swelling of the battery element. The magnetic force sensor is stationary relative to the battery element and is configured to sense a change in the magnetic force intensity between the internal magnetic sensing element and the magnetic force sensor. A controller is configured to measure the expansion of the first electrode based on the change in the magnetic force intensity between the internal magnetic sensing element and the magnetic force sensor independently of the expansion of the second electrode.

[0005] In another feature, the internal magnetic sensing element is located between the first electrode and the second electrode.

[0006] In another feature, the battery element includes a separator between the first electrode and the second electrode, and the magnetic sensing element is located between a first portion and a second portion of the separator.

[0007] In another feature, the first electrode is closer to the magnetic force sensor than the second electrode.

[0008] In another feature, the magnetic sensing element is configured to allow ions to pass through the magnetic sensing element to move between the first electrode and the second electrode.

[0009] In another feature, the magnetic sensing element is porous and configured to allow the electrolyte of the battery element to extend through the magnetic sensing element.

[0010] In another feature, the magnetic sensing element is coated with a non-conductive material.

[0011] In another feature, a support is located between the first electrode and the second electrode, the support supports the first electrode and is configured to allow ions to pass through the support to move between the first electrode and the second electrode.

[0012] In another feature, the magnetic sensing element is arranged adjacent to the first electrode and configured to move away from the magnetic force sensor when the first electrode expands during swelling and to remain stationary when the second electrode expands during swelling.

[0013] In another feature, the magnetic force sensor further includes one of a load sensor, a strain gauge, a pressure sensor, and an electromagnetic force recovery sensor.

[0014] In another feature, the battery element is a pouch element.

[0015] In another feature, the battery element is a prismatic element.

[0016] In various features, the present disclosure also provides a dilatometer for measuring swelling in a coin cell battery. The dilatometer includes: a housing of the coin cell battery; a first electrode within the housing; a second electrode within the housing; a separator within the housing located between the first electrode and the second electrode; an internal magnetic sensing element within the housing configured to move in response to expansion of the first electrode during swelling of the coin cell battery and to remain stationary in response to expansion of the second electrode; an external magnet outside the housing and separated from the housing; a sensor configured to measure the magnetic force intensity between the internal magnetic sensing element and the external magnet; and a controller configured to measure the expansion of the first electrode based on a change in the magnetic force intensity between the external magnet and the internal magnetic sensing element measured by the sensor independently of the expansion of the second electrode.

[0017] In another feature, the internal magnetic sensing element is located between a first portion of the separator and a second portion of the separator.

[0018] In another feature, a support member is located between the first portion of the separator and the second portion of the separator, the support member supports the first electrode and is configured to allow ions to pass through the support to move between the first electrode and the second electrode.

[0019] In additional features, the internal magnetic sensing element is arranged adjacent to the first electrode and configured to move away from the sensor when the first electrode expands during inflation and to remain stationary when the second electrode expands during inflation. The internal magnetic sensing element is further configured as a spacer between the first electrode and the biasing member.

[0020] In various features, the present disclosure also provides an extensometer for measuring the inflation of a first electrode of a button cell battery, the button cell battery including a first electrode and a second electrode. The extensometer includes: a button cell holder configured to hold the button cell battery; an external magnet arranged adjacent to the button cell holder and separated from the button cell battery disposed in the button cell holder; a force sensor configured to measure the magnetic force strength between the external magnet and an internal magnetic sensing element in the button cell battery, the internal magnetic sensing element being configured to move in response to the expansion of the first electrode and to remain stationary in response to the expansion of the second electrode during inflation of the button cell battery; a translation stage configured to support the force sensor; and a controller configured to measure the inflation of the first electrode independent of the inflation of the second electrode based on the change in the magnetic force strength between the external magnet and the internal magnetic sensing element measured by the force sensor.

[0021] In additional features, the external magnet is one of a spherical magnet, a hemispherical magnet, and a conical magnet.

[0022] In additional features, the force sensor includes one of a load cell, a strain gauge, and a pressure sensor.

[0023] In additional features, the button cell holder is configured to hold the button cell battery during at least one of charging and discharging of the button cell battery. The controller is configured to measure the inflation of the first electrode independent of the second electrode during at least one of charging and discharging of the button cell battery.

[0024] The present disclosure provides a dilatometer for measuring battery swelling, the dilatometer comprising: a battery element including a first electrode and a second electrode; an internal magnetic sensing element; a magnetic force sensor, wherein the internal magnetic sensing element is configured to move in response to expansion of the first electrode and remain stationary in response to expansion of the second electrode during swelling of the battery element, and the magnetic force sensor is stationary relative to the battery element, wherein the magnetic force sensor is configured to sense a change in the magnetic force intensity between the internal magnetic sensing element and the magnetic force sensor; and a controller configured to measure expansion of the first electrode based on the change in the magnetic force intensity between the internal magnetic sensing element and the magnetic force sensor independently of expansion of the second electrode.

[0025] Additional fields of applicability of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are intended for illustrative purposes only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present disclosure will be more fully understood through the detailed description and the drawings, wherein:

[0027] Figure 1A and 1B is a side view of an example of a magnetic force dilatometer (MFD) for measuring expansion of an individual electrode of a battery element in accordance with the present disclosure;

[0028] Figure 2 and 3 is a side view of other examples of an MFD for measuring expansion of an individual electrode of a battery element in accordance with the present disclosure;

[0029] Figure 4A and 4B is a side view of another example of an MFD for measuring expansion of an individual electrode of a battery element;

[0030] Figure 5 is a plan view of another example of an MFD for measuring expansion of a battery element with temperature compensation in accordance with the present disclosure;

[0031] Figure 6 is Figure 5 a side view of the MFD; and

[0032] Figure 7 is Figure 5 a perspective view of the MFD.

[0033] In the drawings, reference numerals may be reused to identify similar and / or identical elements. DETAILED DESCRIPTION

[0034] Battery elements, such as lithium-ion batteries (LIBs), experience reversible and irreversible expansion or swelling during cycling. Accurately understanding battery element expansion or swelling can be used to avoid electrode drying, improve battery element life, engineer battery elements, estimate energy density, and / or design battery packs. For next-generation anode materials, such as silicon, battery element expansion or swelling is a much greater concern because some electrode materials experience ~300% volume change during cycling.

[0035] This disclosure relates to a magnetic force dilatometer (MFD) configured to measure battery element swelling during cycling. In the co-assigned U.S. Patent Application No. 18 / 087,452, filed Dec. 22, 2022, and titled “SYSTEMS AND METHODS FOR MEASURING BATTERY DILATION,” which is incorporated herein by reference in its entirety, the MFD is configured to measure battery element swelling during cycling. The entire content of the co-assigned U.S. Patent Application No. 18 / 305,075, filed Apr. 21, 2023, and titled “MAGNETIC FORCE DILATOMETER WITH TEMPERATURE COMPENSATION” is also incorporated herein by reference.

[0036] The MFD according to the present disclosure is configured to measure the swelling of an individual electrode of a battery element independent of the swelling of other electrodes of the battery element. The ability to measure individual electrode swelling enhances the overall understanding of battery element swelling. Knowing the rate of individual electrode swelling and the conditions under which the electrode swells will facilitate advancements in battery element technology.

[0037] Now referring to Figure 1A and 1B , there is shown an MFD 10 for measuring battery swelling. The MFD 10 includes a battery element 20 (e.g., a lithium-ion battery element). The battery element 20 includes a housing 22 that encloses one or more sets of first electrodes 24, second electrodes 26, and a separator 28. Each separator 28 includes a first portion 28A and a second portion 28B. A spacer 30 is arranged adjacent to the second electrode 26.

[0038] A biasing member 32 (e.g., a spring) is arranged between the spacer 30 and the inner surface of the housing 22. The biasing member 32 holds the spacer 30 against the second electrode 26 and is flexible to accommodate movement of the spacer 30 when the first electrode 24 and / or the second electrode 26 expand during swelling.

[0039] The magnetic sensing element 60 is located between the first electrode 24 and the second electrode 26 and is an internal magnet. The magnetic sensing element 60 (e.g., a permanent magnet, an electromagnet, or a ferromagnetic material) is arranged to move within the housing 22 when the first electrode 24 expands during the expansion of the battery element 20. During the individual expansion of the second electrode 26, the magnetic sensing element 60 remains stationary. The magnetic sensing element 60 is located between the first part 28A and the second part 28B of the separator. The magnetic sensing element 60 is configured to allow ions to pass through the magnetic sensing element 60 between the first electrode 24 and the second electrode 26. For example, the magnetic sensing element 60 may include a wire mesh made of nickel or steel, or on the other hand, be porous to allow the electrolyte to pass through it. The magnetic sensing element 60 may also be filled with an electrolyte or made ion-conductive in any suitable manner. The magnetic sensing element 60 may be coated with any suitable non-conductive material to isolate the first electrode 24 and the second electrode 26, thereby preventing a short circuit. For example, the magnetic sensing element 60 may be coated with alumina or a polymer coating (such as polypropylene or polyethylene). In particular, when the magnetic sensing element 60 is coated with a non-conductive coating, the separator 28 is optional.

[0040] The MFD 10 further includes an external magnet 40, which is arranged outside the housing 22 of the battery element 20 and separated from the housing 22. The external magnet 40 can be a hemispherical magnet, a spherical magnet, a conical magnet, a cylindrical magnet, a square magnet, a rectangular magnet, or any other suitable magnet. The external magnet 40 and the magnetic sensing element 60 are arranged within each other's magnetic fields.

[0041] The MFD 10 further includes a sensor 42, which is configured to measure the magnetic force intensity between the external magnet 40 and the magnetic sensing element 60. The sensor 42 can be any suitable force sensor, such as a load cell sensor, a strain gauge sensor, a pressure sensor, etc. In some applications, the external magnet 40 and the sensor 42 can be replaced by a Hall sensor, a magnetoresistor, a fluxgate sensor, a superconducting quantum interference device (SQUID) sensor, a resonant sensor, an induction magnetometer, a reed contact sensor, a Weigand wire sensor, or a magnetic force sensor.

[0042] An optional temperature sensor 46 measures the temperature of the components of the MFD 10 or the ambient temperature around the MFD 10. The controller 50 communicates with the sensor 42 and the temperature sensor 46. The controller 50 is configured to determine the expansion of the first electrode 24 based on the change in the magnetic force intensity between the external magnet 40 and the magnetic sensing element 60. The controller 50 receives a temperature signal from the temperature sensor 46 and performs temperature correction or compensation of the measured expansion based on the temperature sensed by the temperature sensor 46.

[0043] For example, during expansion measurement, a change in expansion occurs in response to the expansion of the first electrode 24 and / or due to temperature variations. The expansion or dilation causes a movement of the magnetic sensing element 60 relative to the external magnet 40. However, the expansion measurement is affected by temperature. In other words, the measurement of the expansion of a cell element at one temperature will be different from the measurement of the expansion of a cell element at another temperature. The controller 50 compensates the expansion measurement based on the measured temperature.

[0044] In Figure 1A , the cell element 20 is shown in a non-expanded state, where the external magnet 40 is separated from the magnetic sensing element 60 by a distance d1. The first electrode 24 has a thickness t1. In Figure 1B the cell element 20 (and in particular, the first electrode 24) is shown in an expanded state. The thickness of the first electrode 24 increases from t1 to t2. As the thickness of the first electrode 24 increases, the magnetic sensing element 60 moves further away from the external magnet 40. For example, in Figure 1A 's non-expanded state, the magnetic sensing element 60 is arranged at a distance d1 from the external magnet 40. In Figure 1B 's expanded state, the magnetic sensing element 60 is arranged at a distance d2 from the external magnet 40, where the distance d2 is greater than the distance d1. At the distance d2, the magnetic attraction between the external magnet 40 and the magnetic sensing element 60 is less than the magnetic attraction at the distance d1.

[0045] In some examples, the controller 50 uses one or more formulas that relate expansion to load element measurements and / or temperature. In other examples, the controller 50 includes a memory that stores: a first calibration table that stores expansion as a function of load element measurements; and a second calibration table that stores expansion compensation values as a function of temperature. The first calibration table includes known magnetic force strengths between the external magnet 40 and the internal magnetic sensing element 60 at different distances d. The second calibration table stores expansion compensation values at different temperatures. In some examples, the first and second calibration tables are combined into a single table indexed by load element measurements and measured temperature and / or strain as a function of temperature.

[0046] Using the first and / or second calibration tables, the controller 50 determines the distance d2 between the external magnet 40 and the magnetic sensing element 60 corresponding to the magnetic field strength measured by the sensor 42, compensated based on the measured temperature. The change in distance (d2 - d1) represents the expansion (t2 - t1) of the first electrode 24.

[0047] The swelling data can be used for various different purposes. For example, knowing the extent to which the first electrode 24 of the battery cell 20 has swollen after a specific number of charge / discharge cycles and / or under various conditions can help in designing batteries that are less susceptible to electrode drying out and have an increased cell lifetime. This information can also be used during the planning of battery cells, the estimation of energy density, and the design of various battery modules and battery packs. An exemplary calibration procedure is explained in more detail herein.

[0048] Now referring to Figure 2 , the sensor 42 is disposed between the external magnet 40 and the housing 22. The sensor 42 is in direct contact with the housing 22 and includes a pressure sensor. Now referring to Figure 3 , the sensor 42 includes a magnetic sensor. In some examples, the sensor 42 is selected from the group including Hall sensors, magnetoresistive sensors, fluxgate sensors, sensors including superconducting quantum interference devices (SQUIDs), resonant sensors, induction magnetometers, reed contact sensors, Weigand wire sensors, and / or magnetic force sensors. The sensor 42 is separated from the housing 22.

[0049] Figure 4A and 4B illustrates another configuration of the MFD 10 according to the present disclosure, which configuration includes a support member 70. The support member 70 is a rigid support member mounted within the battery cell 20 in any suitable manner such that the support member 70 remains stationary. The support member 70 is located between the first electrode 24 and the second electrode 26. The support member 70 is also located between the first part 28A and the second part 28B of the separator. The support member 70 is configured to support the first electrode 24. The first electrode 24 may be disposed directly on the support member 70, or the second part 28B of the separator may be disposed between the support member 70 and the first electrode 24. The second electrode 26 is located below the support member 70, and the first part 28A of the separator is located on the second electrode 26. A void is defined between the support member 70 and the second electrode 26 to allow the second electrode 26 to expand during its swelling.

[0050] The support member 70 is made of any suitable material configured to allow ions to pass between the first electrode 24 and the second electrode 26. For example, the support member 70 may be made of the same material as the magnetic sensing element 60 described in the discussion above in Figure 1A and 1B . However, the support member 70 is not configured as a sensing element and thus does not need to be magnetic. For example, the support member 70 may be made of any suitable glass powder material.

[0051] In Figure 4A and 4BIn the example of, the magnetic sensing element 60 is disposed on the first electrode 24. Accordingly, in response to the expansion of the first electrode 24 during the expansion of the battery cell 20, the magnetic sensing element 60 moves. The expansion of the second electrode 26 itself does not move the magnetic sensing element 60. Thus, during the expansion of the second electrode 26, the magnetic sensing element 60 remains stationary. In Figure 4A and 4B the example of, the magnetic sensing element 60 serves as a separator between the first electrode 24 and the biasing member 32.

[0052] Before the first electrode 24 expands, the first electrode 24 has a thickness t1, and the magnetic sensing element 60 is separated from the external magnet 40 by a distance d1 ( Figure 4A ). In response to the expansion of the first electrode 24, the magnetic sensing element 60 moves to a distance d2 from the external magnet 40 ( Figure 4B ). The distance d2 is greater than the distance d1. The thickness of the first electrode 24 also increases from the thickness t1 to the thickness t2 ( Figure 4B ). The controller 50 receives the change in the distance from d1 to d2, and based on the change in the distance, is configured to measure the expansion of the first electrode 24 in the same manner as described above in the descriptions of the configurations of Figure 1A and 1B . Figure 4A and 4B The configurations of are thus configured to measure the expansion of the electrode that is farthest from the external magnet 40 (i.e., the innermost electrode). Figure 1A and 1B The configurations of are configured to measure the expansion of the electrode that is closest to the external magnet 40 and the housing 22 (i.e., the outermost electrode).

[0053] Now referring to Figures 5 - 7 , another example is shown. In Figure 5 , the sensor 150 is mounted on the battery cell bracket 114 and is configured to measure temperature. The measured temperature is used to compensate for the measured expansion for temperature variations. In some examples, multiple position values of the same battery cell, different battery cells, or battery cells having different chemistries are adjusted to a predetermined temperature so that the results of the dilatometer measurements can be compared with each other.

[0054] The sensor 150 can be configured as a strain sensor configured to measure strain. Since strain is a function of temperature, temperature can be inferred from the measured strain. The measured strain can be directly used to compensate for the measured expansion for temperature variations. The measured strain can also be used to determine the temperature, which can then be used to compensate for the measured expansion for temperature variations. A sensor configured as a temperature sensor can alternatively be mounted in a cavity or hole formed in the cell element bracket 114 and / or another component of the MFD. In some examples, the temperature sensor includes a thermocouple.

[0055] In Figures 5 - 7 this example, the dilatometer 110 is configured to measure the temperature-compensated expansion of any suitable cell element when the cell element is charged and discharged. For example, the dilatometer 110 is configured to measure the Figure 1A , 1B , 2, 3, 4A, and 4B of the real-time expansion of the cell element 20. The dilatometer 110 includes a base 112 (e.g., a bottom plate) and a cell element bracket 114 mounted to the base 112.

[0056] The cell element bracket 114 is configured to hold a button cell element or other type of cell element. Leads are connected to the cell element 20 for charging and discharging the cell element 20. A translation stage 116 is mounted to the cell element bracket 114 to support the load element 120. The load element 120 can be any suitable load element, such as the Miniature S-Bear Jr. Load Cell 2.0 (Model LSB201) from Futek Advanced Sensor Technology, Inc. of Irvine, CA. The dilatometer 110 includes a micrometer 130 for adjusting the vertical height of the translation stage 116 and for adjusting the vertical position of the load element 120 disposed on the translation stage 116.

[0057] A magnet bracket 122 is disposed on the load element 120 and is configured to hold an external magnet 40. In this example, the external magnet 40 includes a spherical magnet. As can be appreciated, the magnet bracket 122 can be configured to hold an external magnet having any other suitable shape. The cell element 20 is supported in the cell element bracket 114 between the external magnet 40 and the compression member 124, and the cell element bracket 114 holds the cell element 20 in place.

[0058] The dilatometer 110 can be used to calibrate the controller 50 and establish the above calibration table. For example, the calibration table can be established as follows. Using the micrometer 130, the translation stage 116 is raised, which raises the external magnet 40. The translation stage 116 is raised until the magnetic field strength measured by the load cell 120 between the external magnet 40 and the magnetic sensing element 60 begins to decrease.

[0059] The magnetic field strength increases until the external magnet 40 touches the housing 22, at which point the magnetic field strength reading begins to decrease. The translation stage 116 is adjusted up or down until the force on the load cell 120 is maximized. Once the force on the load cell 120 is maximized, the controller 50 is configured to begin recording load cell data at any suitable interval.

[0060] For example, the controller 50 can be configured to record one or two readings per second. The translation stage 116 is then lowered in 50 μm increments at least three times while recording multiple values (e.g., 5 - 10 values per step adjustment). The translation stage 116 is raised back to the starting point in 50 μm increments while recording multiple values (e.g., 5 - 10 values per step adjustment). This process can be repeated for other temperatures.

[0061] After calibration, when the battery cell 20 is cycled through charge and discharge cycles, the dilatometer 110 can be used to measure the expansion of the first electrode 24 of the battery cell 20 or any other suitable battery. Leads are connected to the dilatometer 110 to cycle the battery cell 20. The controller 50 is configured to record data from the load cell 120 at any suitable time increment (such as, for example, 5 - second increments).

[0062] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Thus, although the disclosure includes specific examples, the true scope of the disclosure should not be so limited because other modifications will become apparent upon study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method can be executed in a different order (or concurrently) without altering the principles of the disclosure. Additionally, while each embodiment has been described above as having certain features, any one or more of those features described for any embodiment of the disclosure can be implemented in any other embodiment, and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and arrangements of one or more of the embodiments with each other remain within the scope of the disclosure.

[0063] A variety of terms are used to describe the spatial and functional relationships between components (e.g., between modules, circuit components, semiconductor layers, etc.), including "connected", "engaged", "coupled", "adjacent", "next to", "on top of", "above", "below", and "disposed". Unless explicitly described as "direct", when describing the relationship between a first element and a second element in the foregoing disclosure, the relationship can be a direct relationship with no other intermediate elements between the first element and the second element, but can also be an indirect relationship with one or more intermediate elements (spatially or functionally) between the first element and the second element. As used herein, the phrase "at least one of A, B, and C" should be interpreted to mean a logical (A OR B OR C) using non-exclusive logical OR, and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C".

[0064] In the drawings, as indicated by the arrow tips, the direction of the arrow generally shows the flow of information of interest in the illustration (such as data or instructions). For example, when component A and component B exchange various information but the information transmitted from component A to component B is relevant to the illustration, the arrow can point from component A to component B. Such a unidirectional arrow does not mean that no other information is transmitted from component B to component A. Additionally, for the information sent from component A to component B, component B can send a request for the information or an acknowledgment of the receipt of the information to component A.

[0065] In the present application including the following definitions, the term "module" or the term "controller" can be replaced by the term "circuit". The term "module" can refer to, be part of, or include the following: application specific integrated circuit (ASIC); digital, analog, or mixed-mode / digital discrete circuit; digital, analog, or mixed-mode / digital integrated circuit; combinational logic circuit; field programmable gate array (FPGA); processor circuit (shared, dedicated, or group), executing code; storage circuit (shared, dedicated, or group), storing code executed by the processor circuit; other suitable hardware components providing the described functionality; or a combination of some or all of the above in a system-on-chip.

[0066] A module can include one or more interface circuits. In some examples, the interface circuit can include a wired or wireless interface that is connected to a local area network (LAN), the Internet, a wide area network (WAN), or a combination thereof. The functionality of any given module of the present disclosure can be distributed among multiple modules connected via the interface circuit. For example, multiple modules can allow load balancing. In another example, a server (also referred to as remote or cloud) module can perform some functions on behalf of a client module.

[0067] As used above, the term code may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, data structures, and / or objects. The term shared processor circuit includes a single processor circuit that executes some or all of the code from multiple modules. The term group processor circuit includes a processor circuit that, in conjunction with additional processor circuits, executes some or all of the code from one or more modules. References to multiple processor circuits include multiple processor circuits on separate die, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term shared memory circuit includes a single memory circuit that stores some or all of the code from multiple modules. The term group memory circuit includes a memory circuit that, in conjunction with additional memory, stores some or all of the code from one or more modules.

[0068] The term memory circuit is a subset of the term computer-readable medium. As used herein, the term computer-readable medium does not include transitory electrical or electromagnetic signals propagated through a medium (such as on a carrier wave); the term computer-readable medium can thus be considered tangible and non-transitory. Non-limiting examples of non-transitory tangible computer-readable media are non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (such as static random access memory circuits or dynamic random access memory circuits), magnetic storage media (such as analog or digital magnetic tape or hard disk drives), and optical storage media (such as CDs, DVDs, or Blu-ray discs).

[0069] The devices and methods described in this application may be implemented in part or in whole by a special purpose computer created by configuring a general purpose computer to execute one or more specific functions embodied in a computer program. The above functional blocks, flowchart components, and other elements serve as software specifications that can be converted into a computer program by the routine work of those of ordinary skill in the art or programmers.

[0070] A computer program includes processor-executable instructions stored on at least one non-transitory tangible computer-readable medium. A computer program may also include or rely on stored data. A computer program may include a basic input / output system (BIOS) that interacts with the hardware of the special purpose computer, device drivers that interact with specific devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, and the like.

[0071] A computer program may include: (i) descriptive text to be parsed, such as HTML (HyperText Markup Language), XML (eXtensible Markup Language), or JSON (JavaScript Object Notation), (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. By way of example only, source code may be written using the syntax of a language including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Fortran, Perl, Pascal, Curl, OCaml, HTML5 (the fifth revision of the HyperText Markup Language), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Visual Lua, MATLAB, SIMULINK, and

Claims

1. A dilatometer for measuring battery expansion, comprising: A battery cell including a first electrode and a second electrode; Internal magnetic sensing element; Magnetic sensor, wherein the internal magnetic sensing element is configured to move in response to expansion of the first electrode during expansion of the battery cell and remain stationary in response to expansion of the second electrode, and the magnetic sensor is stationary relative to the battery cell, wherein the magnetic sensor is configured to sense a change in magnetic strength between the internal magnetic sensing element and the magnetic sensor; and A controller is configured to measure the expansion of the first electrode independently of the expansion of the second electrode based on a change in magnetic strength between the internal magnetic sensing element and the magnetic force sensor.

2. The dilatometer of claim 1, wherein the internal magnetic sensing element is located between the first electrode and the second electrode.

3. The dilatometer of claim 1, wherein the battery cell further comprises a separator between the first electrode and the second electrode, the internal magnetic sensing element being located between a first portion of the separator and a second portion of the separator.

4. The dilatometer of claim 1, wherein the first electrode is closer to the magnetic sensor than the second electrode.

5. The dilatometer of claim 1, wherein the internal magnetic sensing element is configured to allow ions passing through the internal magnetic sensing element to move between the first electrode and the second electrode.

6. The dilatometer of claim 5, wherein the internal magnetic sensing element is porous and configured to allow the electrolyte of the battery cell to extend through the internal magnetic sensing element.

7. The dilatometer of claim 5, wherein the internal magnetic sensing element is coated with a non-conductive material.

8. The dilatometer of claim 1, further comprising: A support member is located between the first electrode and the second electrode, the support member supports the first electrode, and is configured to allow ions to pass through the support member to move between the first electrode and the second electrode.

9. The dilatometer of claim 8, wherein the internal magnetic sensing element is disposed adjacent to the first electrode and is configured to move away from the magnetic sensor when the first electrode expands during dilatation and remain stationary when the second electrode expands during dilatation.

10. The dilatometer of claim 1, wherein the magnetic sensor further comprises one of a load sensor, a strain gauge, a pressure sensor, and an electromagnetic force recovery sensor.

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