Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
  • H01M10/486—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte for measuring temperature
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/61—Types of temperature control
  • H01M10/615—Heating or keeping warm
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/65—Means for temperature control structurally associated with the cells
  • H01M10/653—Means for temperature control structurally associated with the cells characterised by electrically insulating or thermally conductive materials
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
  • H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• This disclosure relates to the field of energy storage in electrochemical devices of the battery type in particular, and to the second life of such devices.
• Such an electrochemical energy storage device can be used in any electrical device or system of the smartphone, laptop, etc. type, or else respectively of the electric vehicle (EV) type or battery energy storage system. (BES) in particular for operators of an electrical distribution network.
• EV electric vehicle
• BES battery energy storage system
• an electrochemical device of the aforementioned type may comprise a rechargeable battery or a primary battery.
• the rechargeable batteries it may be a lithium-ion battery, a nickel-metal-hydride battery, a nickel-cadmium battery, a lead-acid battery, a solid lithium-ion battery, a lithium-metal solid state battery, a sodium-ion battery, a sodium-ion solid battery, a sodium-metal solder state battery, or even a sodium-sulfur battery.
• the primary batteries it may be an alkaline battery, a lithium battery, a lithium-air battery, or even a zinc-air battery.
• the invention can be applied to all devices and systems in which there are electrochemical energy storage devices of the aforementioned type.
• the estimate of SOH may differ depending on the nature of the electrochemical device (rechargeable or primary).
• electrochemical reactions are usually reversible, but some irreversible reactions (side reactions) may occur.
• side reactions may occur.
• the recharging capacity of the battery decreases due to these irreversible reactions.
• the materials inside the battery cannot be analyzed without dismantling and destroying the device.
• the state of health of the battery is estimated from the charge/discharge capacity and the variation trend of its voltage in operation. In these cases, historical data from the battery is needed to estimate its SOH.
• the obvious method is to charge / discharge the target battery several times to estimate its SOH. This type of estimation is necessary when the battery of an electric vehicle (EV) for example is reused in second life to be used in a BES type system. Normally charging and discharging takes a long time. In the case of large battery systems such as EVs and BES, a large amount of electric power is required, and the process takes a long time.
• EV electric vehicle
• the irreversible reaction is mainly due to the consumption of electrolyte. Focusing on this characteristic, the change in electrolyte composition is proposed as an indicator of SOH. However, the proposed measures require cooling to -40°C relative to ambient temperature. Additionally, precise linear temperature control is required to capture the melting point and/or glass transition temperature of the electrolyte.
• the batteries tested are limited to small cell sizes, typically 40mm x 20mm x 3.5mm in size. If the proposed procedure is applied to large batteries used for EVs and BES, it would require a huge and expensive metering system. Cells are normally assembled in modules. Therefore, users should disassemble the module to extract the cells before applying these measures. These procedures are not practical.
• the proposed procedure can only be applied to batteries containing electrolytes having a melting and/or glass transition temperature.
• solid electrolytes without melting and/or glass transition temperature have been proposed for new generation batteries. In this case, such an estimate of the SOH is not feasible.
• a method for estimating a state of health (or "SoH” for "State of Health” in English) of an electrochemical device comprising the steps: - Record a thermal response of the electrochemical device to a heat input applied to the electrochemical device,
• results presented below show a correlation between a parameter characterizing the thermal inertia of the device and its state of health, so that the measurement of this parameter can make it possible to deduce the state of health of the device, or even to predict its remaining life under similar conditions of use.
• the amount of heat supplied can be "positive” (heating of the device) or “negative” (cooling), the main thing being to measure the thermal response of the device to this supply, and to deduce measurements of the aforementioned parameter.
• the heat input can be produced by a source (cold or hot), external to the device. Alternatively, the heat input can simply result from the normal operation of the device, for example during the charging phases, the device heating naturally during these phases.
• the thermal response of the device can be obtained for example by noting the variation of its temperature over time after (and/or from) the application of the heat input.
• the thermal response can be obtained by measuring a heat flux by a device comprising a Peltier module.
• thermal response of the device via a heat sink or not
• a heat sink or not
• This thermal response can follow the application of a heat source (hot or cold), external, or follow a particular operating phase of the device (load for example). From the analysis of this thermal response, we deduce the state of health of the device.
• the thermal inertia of the electrochemical devices tested increases when the state of health of the device decreases.
• the trend may be reversed.
• the aforementioned measured parameter may include a delay (reference fdeiay) of the start of thermal response of the electrochemical device relative to a start time of application of heat input.
• the thermal response of the electrochemical device as a function of time is recorded and the aforementioned measured parameter comprises a slope of variation of the thermal response as a function of time (dP/dt).
• the heat supply being applied continuously after a moment of start of application of the heat supply, for a chosen duration, then interrupted after this chosen duration, the measured parameter comprises a maximum amplitude (Pmax) of the thermal response of the electrochemical device.
• the measured parameter may comprise a duration (T) for the return of the thermal response of the electrochemical device to a predefined threshold (Po), after an end of application of the heat input, as illustrated in figure 2.
• the electrochemical device is in service during the application of the heat input. Such an embodiment is not necessary to apply the method but is advantageous because it does not require dismantling the electrochemical device to carry out the measurements of the aforementioned parameter.
• measurements of the aforementioned parameter can be stored in memory to monitor changes over time in the state of health of the electrochemical device. It can thus be evaluated a prognosis on the remaining lifetime, for example.
• the method can also provide for the generation of an alert signal when the state of health of the electrochemical device falls below a threshold.
• Such an embodiment then makes it possible to predict, for example, the end of life of the electrochemical device.
• the present invention also relates to a device for estimating a state of health of an electrochemical device, comprising:
• At least one sensor for detecting a thermal response of the electrochemical device to a heat input applied to the electrochemical device
• a processing circuit for measuring in the thermal response at least one parameter representative of a thermal inertia of the electrochemical device, and for deducing from the measurement of said parameter an estimate of the state of health of the electrochemical device.
• the aforementioned sensor may for example be a Peltier module as described below by way of example (using the Seebeck effect for example), or any other means for measuring the thermal response of the electrochemical device.
• the device may further comprise, in one embodiment, a heat transfer device attached to the electrochemical device, and configured to apply the aforementioned contribution of heat to the electrochemical device.
• a heat transfer device attached to the electrochemical device, and configured to apply the aforementioned contribution of heat to the electrochemical device.
• the very operation of the electrochemical device can be the source of a heat input.
• the device may further comprise a sole made of an electrically insulating material, the transfer device being configured to be attached to a first main face of the electrochemical device by means of this sole.
• the transfer device can also be coated in such an insulating material and take the form of a mat heating the electrochemical device.
• the device may also include a heat sink attached to the electrochemical device.
• the heat sink can be attached to a second main face of the electrochemical device, opposite the aforementioned first main face.
• the heat sink can be used for example to measure the thermal response. It is not necessary (but useful for small electrochemical devices to concentrate the heat flux when measuring it).
• the aforementioned processing circuit may comprise in one embodiment a memory for storing at least measurements of said parameter and monitoring changes over time in the state of health of the electrochemical device.
• the present invention also relates to a computer program comprising instructions for implementing the steps of the method presented above, when said instructions are executed by a processing circuit.
• a non-transitory, computer-readable recording medium on which such a program is recorded.
• FIG. 1 illustrates a schematic example of a device for measuring the heating and the thermal response of an electrochemical device according to one embodiment.
• FIG. 2 illustrates the typical thermal response of the electrochemical device after energization by a heat source.
• FIG. 3 illustrates the thermal response (with a heat flux peak) after power supply by a heat source applied according to a step power (range on the left of figure 3) of a cell at 99.5%, 91.5% and 87.4% SOH.
• Fig. 4 illustrates the thermal response (with a heat flux peak) after power supply by a heat source applied according to a step power (range on the left of figure 3) of a cell at 99.5%, 91.5% and 87.4% SOH.
• Fig. 4 illustrates the thermal response (with a heat flux peak) after power supply by a heat source applied according to a step power (range on the left of figure 3) of a cell at 99.5%, 91.5% and 87.4% SOH.
• Fig. 4 illustrates the thermal response (with a heat flux peak) after power supply by a heat source applied according to a step power (range on the left of figure 3) of a cell at 99.5%, 91.5% and 87.4% SOH.
• FIG. 4 illustrates the thermal response of another electrochemical device to different device health states.
• FIG. 5 shows the correlation between the slope of the temporal variation of the thermal response as a function of time (dP/dt), to the state of health of the device.
• FIG. 6 shows the correlation of the return time (T) of the thermal response, to the state of health of the device.
• FIG. 7 shows the correlation of the peak height (Pmax) of the thermal response, to the state of health of the device.
• FIG. 8 shows the correlation of the delay (tdeiay) of the thermal response after application of a heat input, to the state of health of the device.
• FIG. 9 illustrates a device comprising a CT processing circuit according to one embodiment of the invention.
• FIG. 10 illustrates the steps of a method according to one embodiment of the invention.
• the electrochemical devices are typically those for which, in the case of rechargeable devices, a drop in capacity has been reached following one or more irreversible reactions, initiating the device degradation. Indeed, when the SOH of the device changes, an irreversible reaction occurs inside the device. This irreversible reaction creates new phases in the device material, having different thermal properties such as heat capacity and/or heat transfer. For example, in the case of lithium batteries in particular, a deposit containing lithium can be observed at the anode. Furthermore, this irreversible reaction induces a change in the volume of the device. These property changes can occur simultaneously or independently.
• the reference “a” designates an electrochemical device of the battery type for example
• the reference “c” designates a temperature or heat flux sensor
• the reference “d” designates a heat sink.
• Thermal energy is applied to the electrochemical energy storage device, and the thermal response is obtained to estimate the SOH of the device.
• the energy is applied, for example, by a heating element placed on the device, as shown in Figure 1.
• a cooling device can also be used to change the thermal state of the device in a controlled manner.
• the cooling device may include a Peltier effect module.
• the heat or cold sources can be placed outside or inside the electrochemical device.
• the “supply” of thermal energy (therefore positive or negative) consists, for example, in applying an energy, the value of which is known, in order to modify the thermal state of the device as shown in FIG.
• One way to proceed may consist in applying a thermal energy corresponding to the maximum increase in the thermal response.
• the temperature of the device begins to rise or fall. Then, after a long supply of energy to the device, its temperature reaches an equilibrium state and the additional energy applied is then released to the environment due to the heat transfer between the device and the surrounding atmosphere. Between the starting point of the power supply and the steady state of the device, the temperature therefore reaches a maximum, as shown in Figure 2. This point is the most important to compare the difference of the thermal properties of the device.
• the procedure proposed above is only a non-limiting example.
• Another method may consist in comparing the relaxation rate after the supply of thermal energy.
• the thermal relaxation rate of the material is expressed by "Newton's cooling law".
• the thermal relaxation exhibits an exponential relationship with time and the exponential term includes a heat transfer coefficient which occurs, for such electrochemical devices, as having a proportional relationship with the heat capacity of the device C, and an inverse relationship with the heat transfer coefficient a.
• the change in device volume also induces a change in thermal capacity and/or heat transfer. Therefore, the SOH can be estimated by measuring the relaxation rate of the device after the thermal energy supply.
• Another parameter characterizing the thermal inertia of the electrochemical device is the slope of the temporal variation of the thermal response (for example the rising slope in FIG. 2).
• the applied thermal energy detection method can be selected from several choices.
• thermocouple thermistor
• RTD resistance-temperature detector
• temperature thermometer infrared radiation can be used.
• a Peltier effect module as a thermal flux sensor.
• Such a sensor measures the heat flux by delivering an electrical signal (in mV for example) by Seebeck effect and thus makes it possible to measure the thermal response of the electrochemical device (measurement given in mV in the experimental procedures presented below as example).
• heat flux generated by the device is too low to modify its measured temperature
• a heat flux sensor can be used between the device and the outside atmosphere or between the electrochemical device and a heat sink, bearing the reference “d” in the figures.
• Such a realization makes it possible to increase the signal-to-noise ratio of the measurements.
• a lithium-ion battery is used below as a sample for tests, the results of which are illustrated in FIG. 3.
• the nominal capacity of the battery is 4000 mAh. Its size is 50mm (width) x 90mm (length) x 5mm (thickness).
• the battery was charged and discharged at 200mA between 4.4V and 3.0V.
• the reversible capacity starting point was set for 100% SOH. Then the battery was continuously charged and discharged. After a few first cycles, the capacity conservation was verified under the same conditions as those defined at the beginning of the experimental procedure.
• the thermal property of the battery was measured as follows.
• the battery under test was placed in a temperature-controlled chamber set at 25°C.
• the battery was heated using a heating element, such as a heating mat separated from the battery (or coated) by a rubber sole (rubber being a heat conductor but an electrical insulator), and attached to battery.
• the heat applied was 0.74 W for 180 seconds.
• the thermal response of the battery was measured using a Peltier module attached to the opposite side of the heating element. The Peltier module is then inserted between the battery and an aluminum plate (acting as a heat sink).
• the difference between the highest value of the thermal response and the base PO value was defined as Pmax.
• the cooling rate thereafter was defined using the following equation:
• P Po + A.e ⁇
• P the thermal response.
• PO is the base value of the thermal response.
• A is a function of the applied power
• t is the elapsed time.
• tO is the heating start point.
• T is the battery cooling rate.
• Pmax is obtained by observing the largest peak value P - PO.
• the thermal response using the proposed procedure can be an indicator to estimate the SOH of the battery.
• the battery volume is also an indicator to estimate the SOH of the battery, and can corroborate the estimation of SOH by thermal measurement.
• the proposed procedure for estimating the SOH of a device using its thermal response changes thus depends on the heat capacity and/or heat transfer of the materials inside.
• This procedure using the thermal response can be applied to other devices using other detection methods.
• a similar technique can be applied to determine the degree of corrosion because the thermal response is influenced by the formation of an element corrosive.
• a similar technique can be applied to determine the degree of water absorption, as the thermal response is influenced by the formation elements related to water absorption.
• Such a method can therefore be proposed for estimating the SOH of an electrochemical device during the actual operation of the system of which it is part, such as electric cars and BES systems.
• a large number of devices are used.
• the SOH of the total system can be estimated during system operation, such as during charging and discharging.
• dismantling the system is mandatory to measure the SOH of each device.
• the proposed method can allow to estimate the SOH of a device without any disassembly operation because each device can be easily equipped with a thermal source and a thermal sensor.
• Such an embodiment makes it possible to identify and replace a defective device in a storage system instead of replacing the entire system and can be useful to operators of electrochemical storage systems.
• an electrochemical storage device can be used in a second life in a BES system. This type of second use is recommended to reduce the carbon footprint of the lifecycle device, to increase the resale value of the EV, and to reduce the cost of installing the BES.
• the estimation of the SOH of each device is necessary.
• the individual estimation of the SOH using the realization described above is useful.
• FIG. 4 illustrates the thermal response of another electrochemical device, for different states of health of the device.
• Thermal inertia parameters such as:
• FIG. 9 illustrates a CT processing circuit connected to the sensor c to measure the thermal response to the AC heat input that the CT processing circuit can drive (the references a, b, and c of Figure 1 representing the same elements in figure 9).
• the processing circuit CT can typically comprise a processor PROC cooperating with a storage memory MEM to read and execute there instructions of a computer program of the type presented above (as well as thermal response measurement values, and parameter values thermal inertia at different timestamps, estimated health status values, or others).
• the processor PROC can also control the heat input as well as the recovery of the SS measurement by the sensor c.
• the processing circuit CT can thus be configured for:
• step S2 drive the sensor to record a thermal response of the electrochemical device to the heat input
• the measurement of the thermal response can be ensured by the sensor c by various means such as:
• thermocouples to measure a temperature
• thermoelectric module for example of the Peltier type by Seebeck effect (to measure a heat flux, the measurements in the tables above having been obtained by such means),
• thermometers infrared for example.
• the heat input can be ensured by applying a heat or cooling source which can be for example:
• the environment of the electrochemical device itself when handling an electrochemical device from a storage warehouse at a given temperature (for example 25° C.) to another environment (at a different temperature), it can be to a measurement of its thermal response to this temperature variation, and from there, to an estimate of its state of health.
• a given temperature for example 25° C.
• another environment at a different temperature
• the simple movement of the device electrochemical in an environment with a different temperature can be conducive to measuring its state of health. It is thus possible to sort, during this simple movement, the electrochemical devices likely for example to be reused in a second life, from those which should be definitively recycled.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Investigating Or Analyzing Materials Using Thermal Means (AREA)
• Secondary Cells (AREA)
• Tests Of Electric Status Of Batteries (AREA)

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• 2021
  • 2021-09-14 FR FR2109649A patent/FR3127046B1/fr active Active
• 2022
  • 2022-09-07 CN CN202280066326.7A patent/CN118043224A/zh active Pending
  • 2022-09-07 EP EP22783429.8A patent/EP4402016A1/de active Pending
  • 2022-09-07 JP JP2024516502A patent/JP7728965B2/ja active Active
  • 2022-09-07 WO PCT/EP2022/074858 patent/WO2023041395A1/fr not_active Ceased

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