ASSEMBLY OF ELECTRICAL ENERGY STORAGE OR GENERATION CELLS INCLUDE MANAGEMENT CIRCUIT FOR MANAGING THE CELLS - Patent application

Abstract

To provide an assembly of electrical energy storage or production cells, comprising a management circuit for managing the cells.SOLUTION: An assembly able to deliver an output current Ii includes: N electrical energy storage or production cells Bi of rank i, which are able to supply a maximum current at all times t; and a management circuit for managing the electrical energy storage or production cells. In the assembly, the cells are classified according to their rank i in decreasing priority of use. The management circuit comprises means for addressing at least the cell of rank 1 or the cells according to their rank i and according to the following criteria: the cell of rank 1 is addressed on its own as long as it is able to supply the output current; and the cell of rank 1 is addressed with the number of cells that are addressed successively according to their rank i, so as to supply current Is at all times in discharge mode, while predetermined conditions are satisfied.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The field of the invention is that of assemblies of electric energy storage or production cells such as batteries, hydrogen fuel cells, etc., and more particularly assemblies including a management circuit for managing the cells, making it possible to increase the usable energy of said assembly or the duration of autonomy of the system otherwise supplied by said assembly. [Background technology]

[0002] The problem addressed by the present invention relates to the reduced capacity to supply current starting from a particular state of charge and the reduced period of autonomy of a system supplied by an electrical energy storage or generation cell.

[0003] In general, the charge and discharge regime of a battery can be characterized by a parameter commonly referred to as the "C-rate." A 1 mAh battery rated at 1C means that the battery is capable of delivering 1 mA for 1 hour when discharged at a 1C regime.

[0004] The storage capacity of a battery is generally provided by the manufacturer with the battery's specifications and corresponds to the product of the nominal current and the time that the battery is able to deliver at 20° C. until the battery's predefined end-of-discharge voltage is reached. The nominal capacity of a battery is thus linked to the expected discharge period.

[0005] Applicant has demonstrated that for microbatteries, starting from a particular discharge state, there is a steep drop in the capacity to deliver a nominal current, which is less pronounced and more gradual in high-capacity lithium-ion batteries, but is also present in high-capacity lithium-ion batteries.

[0006] This problem is therefore of general concern, including in the context of high power applications such as transportation (bikes, cars, lorries, trains, etc.), autonomous systems (solar radio repeaters, roller shutters, connected objects, etc.), and power storage.

[0007] Generally, a microbattery is an electrochemical device consisting of two electrodes (positive and negative) separated by an electrical insulator and an ionic conductor (electrolyte) in which ions (e.g., lithium ions) are transferred from one electrode to the other depending on whether the microbattery is being charged or discharged.

[0008] The target fields of application (Internet of Things, medical implants, autonomous sensors, etc.) impose strong constraints on the size of the energy source supplying the device. The positive electrode forms a lithium ion reservoir and the amount of energy stored is directly related to its volume (at constant density).

[0009] One straightforward way to increase the capacity of a microbattery may involve, for example, increasing the thickness of the cathode, typically beyond 10 μm. It is also possible to form stacks of multiple battery units connected in parallel, thereby keeping the same surface footprint.

[0010] However, these solutions have several drawbacks. - the sputtering deposition technique of the cathode is limited to a thickness of more than 10 μm, and increasing the thickness of the positive electrode leads to an increase in surface and volume imperfections, possibly leading to failure of the microbattery; - Microbatteries exhibit an irreversible loss of capacity between the first charge and the first discharge, which is more pronounced if the cathode thickness is large and is therefore particularly detrimental for positive electrodes with a thickness of more than 10 μm.

[0011] Figure 1 shows a lithium-based microbattery (LiCoO 2 The charging current I and the potential difference E (V vs. Li) of a microbattery as a function of the charge and discharge capacities with a positive electrode made of Li, a negative electrode made of titanium, and a solid electrolyte made of LiPON. + / Li) more precisely.

[0012] Figure 1 shows the current profile during charging (dashed curve with current scale on the right and charge scale Ah above) at a constant potential of 4.2 V. During discharge, a constant current of -6 μA is applied and the potential difference (undashed curve with voltage scale on the left and discharge scale Ah below) varies from 4.2 V to 3 V.

[0013] The loss representing 30% to 40% of the total capacity (the difference between the charge capacity and the discharge capacity highlighted by the horizontal arrow) is due to the kinetic limit at the end of the discharge. However, it is possible to overcome this limit, but the discharge current would drop significantly, thereby making it impossible to supply any component outside the stationary mode.

[0014] Figure 2 shows this case, more precisely the evolution of the discharge current (expressed in μA) as a function of the discharge capacity (expressed in μAh). Figure 2 also shows the potential difference E (V vs. Li + / Li) is highlighted.

[0015] In the first regime, the microbattery can typically be operated with an applied current of -6 μAh, resulting in a voltage drop across the terminals of said microbattery, while in the second regime, it is typically possible to maintain a voltage of 3 V, while the discharge current drops free, varying from -6 μAh to a much lower current close to zero.

[0016] In the second regime, it is also possible to impose very low currents, as shown in FIG.

[0017] It was therefore shown that in both situations the discharge current becomes very low and it is no longer possible to achieve a sufficient current supply in the second regime.

[0018] Therefore, it becomes necessary to use energy management circuitry in conjunction with the microbattery to overcome the above drawbacks.

[0019] Devices proposed for managing energy with stacked microbatteries are known in the field of microbatteries and are described in particular in the University of Michigan patent US Reexamination Registered Patent No. 009635147 B2. The microbattery provides a capacitive charge reservoir whose function is to power an external circuit by providing current peaks required by the application.

[0020] This charge reservoir is periodically recharged by a microbattery during operation of the device. Periodic recharging leads to an inherent limit in the information transmission rate. Furthermore, larger reservoirs are more expensive in terms of surface area and manufacturing.

[0021] Document US Patent No. 009252415B2, Medtronics, also discloses arranging microbatteries in parallel by stacking wafers, the chips being connected by redistribution and via layers during the stacking process.

[0022] However, the two solutions mentioned above do not address the issue of irreversible losses after the first cycle, which compromises the capacity and volumetric footprint of the components for the desired purpose, especially when the cathode thickness is large (thickness greater than 10 μm). [Prior art documents] [Patent documents]

[0023] [Patent Document 1] US Patent No. 009635147B2 [Patent Document 2] US Patent No. 009252415B2 Summary of the Invention [Means for solving the problem]

[0024] The applicant has focused on this irreversible loss and has shown in particular that in the second discharge regime of the microbattery, which may represent up to 34% of the stored energy, the current is too low to guarantee the nominal operation of the application.

[0025] To solve this problem, the Applicant proposes an assembly of electrical energy storage or generation cells, including an energy management circuit, optimizing the duration of autonomy of the assembly, in particular keeping one cell available in its first regime, while allowing the other cell or cells to continue to supply current in the second regime (second discharge part). This solution may be particularly suitable for the case of microbatteries, but is also relevant for any other case of electrical energy storage or generation cells, allowing them to continue to supply the application current for a longer period of time.

[0026] The discharge of cells is prioritized to use the second regime as soon as possible, and subsequent cells are successively switched in to provide the additional current required to meet the needs of the application from time to time. This can lead to an increase in capacity of about 30% to 35% compared to the standard case where the battery only discharges over the first 66% during operation.

[0027] It should be noted that for the purposes of this invention, a battery or electrical energy storage or production cell is defined as being one elementary cell or an assembly of multiple elementary cells arranged in series and / or parallel.

[0028] The assembly of the present invention includes a set of cells and associated management circuitry, - A set consists of two or more cells, - Energy is provided stepwise by each cell to utilize its full capacity, smoothing out the effects of kinetic limitations in the second regime; - Cells in different regimes can be addressed simultaneously depending on the charging stage of the cells, the cells and the management circuitry may advantageously be comprised in a 3D stack, - In the case of a cell such as a conventional micro battery described in the preamble, the larger the total capacity, the more significant the loss. Therefore, the thickness of the positive electrode can usually be more than 10 μm, although not limited.

[0029] More particularly, the present invention - N electrical energy storage or generation cells of rank i, where N ≧ 2, and each cell includes a basic cell or a basic assembly of basic cells arranged in series and / or parallel, and each electrical energy storage or generation cell can supply a maximum current I max,i at all times t, - A management circuit for managing the electrical energy storage or generation cells including, s in an assembly capable of delivering an output current I wherein the electrical energy storage or generation cells are classified according to their rank i in decreasing order of usage priority, and the management circuit, in the discharge mode, according to its rank i and the following criteria: - The electrical energy storage or generation cell of rank 1 is addressed by itself as long as it can supply the output current I s where I s < I max1 and - The electrical energy storage or generation cell of rank 1 is further addressed together with k electrical energy storage or generation cells that are successively addressed according to its rank i, and supplies the current I s at all times of the discharge mode, where the number k is such that 2 < k ≦ N and the following conditions:

Number

[0030] According to some variants of the invention, a management circuit for managing an electrical energy storage or generation cell comprises: - Block of rank i (M i ) each electrical energy storage or generation cell is coupled to a block, each cell coupled to a block being capable of delivering an output current; The set of blocks outputs a current I i The output current I is equal to the sum of s The block generates a current value I max,1 Select a first electrical energy storage or generation cell until it is completely depleted, and then select a current value I max,2 , a second electrical energy storage or generation cell is selected until it is completely depleted, and then an Nth electrical energy storage or generation cell is selected.

[0031] According to some variants of the invention, each block includes a switch and a management circuit for managing the electrical energy storage or generation cells controls each of the electrical energy storage or generation cells in an all-or-nothing mode and through hysteresis.

[0032] According to some variants of the invention, each block outputs a reference output voltage Uth i The assembly includes a regulator having an output voltage V s each block includes a regulator operating with a voltage threshold, and the voltage threshold of the regulator may be Uth 2 >Uth 3 >...>Uth N and - Rank 1 cell is V s ≧Uth 2 If it is, it is activated by itself, I max,1 Supplying -V s <Uth 2 then the second cell is activated in addition to the first cell to provide additional current; -V s <Uth N If so, then the Nth cell is activated in addition to the lower ranked cells to provide additional current.

[0033] According to some variants of the invention, the assembly includes an output voltage V s each block has a set point voltage; and - Output voltage V s is lower than the set point voltage, the output voltage V s providing current at the output to maintain the set point voltage; and - When the output voltage Vs is greater than this set point, it supplies zero current. The present invention is characterized in that it includes a switch mode converter capable of

[0034] According to some variations of the invention, the assembly includes electrical energy storage or generation cells having different capacitance values.

[0035] According to some variants of the invention, the electrical energy storage or generation cells have a capacitance value that decreases according to the rank i.

[0036] According to some variants of the invention, the management circuit includes means for placing all of the cells in parallel, in recharge mode, corresponding to a negative output current -Is.

[0037] According to some variants of the invention, the management circuit, in the recharge mode, s Correspondingly, the memory cell includes means for addressing a cell having a higher rank as a priority from rank N to rank 1.

[0038] According to some variations of the invention, the basic electrical energy storage or generation cell is a battery.

[0039] According to some variations of the invention, the basic electrical energy storage or generation cell is a microbattery.

[0040] According to some variations of the invention, the basic electrical energy storage or production cell is a hydrogen fuel cell.

[0041] According to some variations of the invention, the microbattery and the management circuitry are included in a 3D stack.

[0042] The invention will be better understood and other advantages will become apparent on reading the following description, given without limitation, and from the figures, in which: [Brief description of the drawings]

[0043] [Figure 1] 1 shows the capacity loss between the first charge and the first discharge of a known prior art microbattery. [Diagram 2] 1 shows the behavior of the voltage and current during the discharge operation as a function of time in the second regime of a microbattery maintained at a voltage of 3 V in particular. [Diagram 3] 1 shows the behavior of the voltage and current during the discharge operation as a function of time, especially in the second regime of the microbattery maintained at a very low discharge current. [Figure 4] 1 shows a first example of an energy management circuit for a microbattery according to the prior art. [Diagram 5] 2 shows a second example of an energy management circuit for a microbattery according to the prior art. [Figure 6] 1 illustrates diagrammatically an assembly including an energy management circuit according to the invention; [Figure 7a] 2 shows an example of blocks correlated with cells that can be used in an assembly including an energy management circuit according to the invention. [Figure 7b] 2 shows an example of blocks correlated with cells that can be used in an assembly including an energy management circuit according to the invention. [Figure 7c] 2 shows an example of blocks correlated with cells that can be used in an assembly including an energy management circuit according to the invention. [Figure 8]1 shows an example of output current generation as a function of time correlated with one, two, three or four cells in an example assembly including an energy management circuit operating with a set of four cells according to the present invention. [Figure 9] 4 shows the output current behavior as a function of time for an example of an assembly including an energy management circuit according to the invention, including two identical cells. [Figure 10] 4 shows the output current behavior as a function of time for an example of an assembly including an energy management circuit according to the invention, including two different cells. [Figure 11] 4 shows the output current behavior as a function of time for an example of an assembly including an energy management circuit according to the invention, including three different cells. [Figure 12] 1 shows an example of an assembly including an energy management circuit according to the present invention that includes a switch-based block. [Figure 13] 13 shows an example of an algorithm for controlling a cell, implemented through hysteresis in all-or-nothing mode, during a discharge operation and usable in the management circuit of an assembly such as the one shown in FIG. [Figure 14] 1 shows an example of an algorithm for controlling a cell that can be used in the management circuit of an assembly according to the invention, working in linear mode and defined by its threshold voltage (operation in discharge). [Figure 15] Here we show an example of an algorithm for controlling the cells that can be used in the management circuit of an assembly according to the invention, operating in linear mode and defined by the balance between the current available in each cell and the current required (operating in discharge). [Figure 16] An example of an algorithm for controlling the cells that can be used in the management circuit of an assembly according to the invention, operating in linear mode, is given, defined by the balance between the allowable recharge current in each cell and the overall recharge current during the recharge operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] Generally, in this patent application, a cell is defined as a cell that is made up of a number of elementary subcells CE ijCell B consists of the assembly of i As illustrated in FIG. 6 below which shows a basic electrical energy storage or generation cell, the basic electrical energy storage or generation cell is defined as one basic electrical energy storage or generation cell or a basic assembly of multiple basic electrical energy storage or generation cells arranged in series and / or parallel.

[0045] Basic Cell CE ij is usually an electrochemical couple in batteries, microbatteries, hydrogen fuel cells, etc. This elementary cell may be combined in series with other elementary cells to achieve a particular voltage, such as 12V for a lead acid battery with six elements combined in series, and / or in parallel to provide higher current.

[0046] In the following detailed description, the elementary cells are microbatteries, but the applied management circuits can nevertheless be the same for a wider range of elementary cells other than microbatteries.

[0047] As shown in FIG. 6, the management circuit i Block M connected to i Includes.

[0048] All Blocks M i The desired objective with I is to prioritize one cell until it is completely depleted, then prioritize a second cell until it is completely depleted, etc., but with a maximum current value I for each cell that depends on the state of charge of the cell. max,i not exceed.

[0049] current I s is imposed by the output load and can vary over time according to needs. This means that each cell has a maximum current I that it cannot exceed at any given time. max,i Knowing that it is possible to supply block M i The current I at each output of 1 , I 2 , ..., I N It results from the sum of.

[0050] Block M ican be of different types, for example controlling the current through a connection rate, a step-down assembly or a voltage regulator.

[0051] 7a, 7b and 7c show the input of cell B i and an optional resistor R i At the output, a load C out Block M connected to i More specifically, FIG. 7a shows three examples of switches K i and capacitor C Mi FIG. 7b shows an example of a device with series filtering and switching including two switches K i1 and K i2 , capacitor C Mi and inductor L Mi FIG. 7c shows an example of a switch mode converter device including a voltage regulator Rg i These three exemplary blocks M i can adjust the current to selectively address or not address the cells coupled to said block.

[0052] An example is shown in Figure 8 over time, where the output current I s For example, in cell B 1 takes priority, then cell B 2 , then cell B 3 , and finally cell B 4 takes priority to satisfy the current demanded by the output at all times t.

[0053] In particular, according to the invention, cells are sorted according to rank i, which increases with decreasing usage priority.

[0054] Cell B 1 is addressed as a priority and has sufficient current I max,1 ≧I s If it is possible to supply a 1, then it is the only cell that is addressed.

[0055] I max,1 <I s If it is , it is necessary to determine the number k of cells to be addressed in order to satisfy the required output current while conforming to the priority order.

[0056] Electric energy storage or generation cell B of rank 1 1 is further addressed together with k electric energy storage or generation cells B that are successively addressed according to rank i, and supplies the current Is at all times in the discharge mode. The number k is such that 2 < k ≦ N, where N is the number of cells present in the assembly, and the number k satisfies the following condition: i

Equation

Number

[0057] The applicant of the present application performed simulations using assemblies including variable lithium-ion microbatteries such as those shown above with and without the management circuit according to the present invention to successively address a plurality of microbatteries.

[0058] The assumptions of the simulation are as follows: - It is necessary to constantly apply an application equal to 4 μA. - Considering a total capacity of 108 μAh distributed over N microbatteries (for example, employing 3 cells in parallel of 36 μAh), 72.2% (78 μAh) of the capacity can be reached using the current in the first regime of C / 6, i.e., 18 μA (the current equal to dividing the capacity by 6 hours: 108 μAh / 6 h).

[0059] The remaining 27.8% (30 μAh) of the capacity can be reached using the current in the second regime equal to the capacity divided by 36 (using the current of C / 36), i.e., 3 μA.

[0060] Use of a single cell If only one microbattery of 108 μAh (possibly consisting of several microbatteries in parallel) is used, it is possible to satisfy the application (4 μA) only with the current in the first regime (18 μA) and the current in the second regime, which is equal to 3 μA, is less than the applied current of 4 μA. Only 72.2% of the capacity of the microbattery, i.e. only 78 μAh or an autonomy of 78 μAh / 4 μA=19.5 h, is usable.

[0061] Use of two cells within the scope of the present invention Use of two identical cells within the scope of the present invention Two identical cells of 54 μAh each (total capacity 108 μAh) are taken as an example. Each cell has a current I max and the current I in the second regime, which is 54 μAh / 36=1.5 μA. max has.

[0062] The current profile as a function of time is shown in Figure 9, I 1 is the current drawn from the first cell (4 μA), and I 2 is the current drawn from the second cell (the second regime is shown in hatched form compared to the first regime).

[0063] 72.2% of the 54μAh capacity is capable of supplying a current of 4μA for 584.8 minutes.

[0064] When switching to the second regime of the first cell, the current I of the second regime established at 1.5 μA max,1 It can only supply the following current:

[0065] Next, the second cell is addressed, which is responsible for sourcing an additional current of 2.5 μA (additional from 4 μA-1.5 μA), which is the I max,2 (9μA).

[0066] By splitting the capacity of the microbattery in two (unshaded and shaded areas in FIG. 9) and prioritizing the discharge of one of the two, the device is able to deliver the required 4 μA for 23.25 hours, i.e. the autonomy is increased by 3.75 hours or +19% compared to a single microbattery with equivalent nominal capacity.

[0067] Beyond 1395 minutes (23.25h) the device is only able to supply 1.5μA, which is no longer sufficient to supply the application, and therefore this residual energy is not used.

[0068] Use of two different cells optimized according to the present invention The same reasoning is followed to consider two different cells to gain more autonomy and optimize the relative capacity of the two cells. The applicant has run simulations with cells having different capacities, showing an optimum of 86 μAh for one cell and 22 μAh for the other.

[0069] The current profiles achieved with this optimization of two different cells as a function of time are shown in Figure 10 and show I 1 is the current drawn from the first cell, and I 2 1 shows the current profile where x is the current drawn from the second cell.

[0070] The autonomy delivering 4 μA then changes to 25.5 h, ie 2.25 h longer than before and 6 h longer than in the case of a single cell.

[0071] Use of three cells within the scope of the present invention Use of three identical cells within the scope of the present invention When using three identical cells of 36 μAh (for a total of 108 μAh), the autonomy is 24.375 h, which is better than using only one cell or two identical cells, but not as good as using two cells well optimized for each other.

[0072] Use of three different optimized cells within the scope of the present invention The Applicant has demonstrated an optimal autonomy using three cells of 89 μAh, 11 μAh and 8 μAh respectively, making it possible to achieve an autonomy of 26.12 h, ie 0.625 h longer than with the two optimal cells.

[0073] The current profile achieved using this optimum condition as a function of time is shown in Figure 11 and is I 1 is the current drawn from the first cell, and I 2 is the current drawn from the second cell, and I 3 4 shows the current profile where x is the current drawn from the third cell.

[0074] In conclusion, these simulations show that the solution presented in the present invention makes it possible to achieve gains in terms of autonomy (compared to three cells addressed in parallel and three optimized cells addressed according to the management circuit proposed in the present invention) that can possibly reach approximately 33%.

[0075] First Example of an Algorithm for Controlling a Cell in an Energy Storage Device Including a Control Circuit According to the Invention The assembly of the invention may be as shown diagrammatically in FIG. i Cell B merged to i Includes.

[0076] According to this first example, the cell is controlled through hysteresis in an all-or-nothing mode, as explained below.

[0077] During operation in discharge mode, cell B is classified as having a lower usage priority. 1 , B 2 , B 3 , ..., B N Taking the example of (B 1 is the first to be connected, and B N is the last one to be connected).

[0078] U high is the upper voltage threshold, and U low are the lower voltage thresholds, which relate to the nominal operation of the cell. These are hysteresis thresholds that may differ from the minimum and maximum voltage thresholds that the cell can withstand. Typically, U low can be close to the minimum voltage of the cell specified by the manufacturer (e.g., +5% to +20% of this limit), while U high may be approximately halfway between the minimum and maximum voltages specified by the manufacturer.

[0079] The operation in the discharge mode is as follows.

[0080] Cell B 1 is actually always connected in discharging mode. There is a state "0" shown in FIG.

[0081] The discharge voltage is usually + / The lower voltage threshold U, which can be 3V for Li batteries low You should not descend further than this.

[0082] First, cell B 1 When is in discharge mode, V s ≧U low As long as B 1 Only B is activated. 1 is the current I max,1 can be supplied.

[0083] V s low If so, the system changes to state “1” in Figure 13 and cell B 1 In addition to cell B 2 Each time the system passes through state “1” in FIG. 13, the index i is incremented by 1 (i=i+1), unless i has already reached N, which means that the higher rank B i+1 1 shows a schematic diagram of the connections of the cells.

[0084] ​After a selected standardized time, called Delay 1, a return to state "0" occurs and the set of cells is connected in discharge mode.

[0085] Therefore, the principle is that the output voltage Vs exceeds the lower voltage threshold U low If it falls below, the next cell B i+1 This includes connecting the

[0086] Upper cell hysteresis voltage U High There are also.

[0087] In addition, the voltage V s V s >U High If so, then it is preferably decided to disconnect the connected cell with the highest index. This disconnection operation is shown in state "2" of figure 13 and is indicated diagrammatically by the change of i=i-1.

[0088] Following an increment or decrement (within the limits of stops 1 to N) of the number of connected cells, a short waiting period DELAY1 or DELAY2 may be applied before returning to state "0" so that the output voltage has time to stabilize to the new value following the configuration change and avoids corner-high frequency switching (e.g., above 100 KHz) that could lead to an instability situation between the two values ​​of i.

[0089] In the recharge mode, all the cells are placed in parallel and, typically, when the charging system is not actually limited in terms of current as to the current with which it can recharge the cells, it is said that all the cells are recharged simultaneously.

[0090] On the other hand, if the current available for recharging is relatively moderate (not all cells can be charged at high speed), then reverse priority may be applied by prioritizing the recharging of cell N, then cell N-1, etc., quickly giving the system the potential to deliver high current again.

[0091] A second example of an energy storage device including a control circuit according to the present invention According to this second example, the battery cells are controlled in a linear mode.

[0092] Referring to FIG. 6, each cell B i is a block or management circuit M i This management circuit may for example be of the type of FIG. 7b or of FIG. 7c.

[0093] This type of management circuitry allows for more precise management of the current contribution of each cell to the output current.

[0094] For example, if two cells contribute, cell B 2 Cell B 1 This allows a higher current to be selected.

[0095] The linear mode can be defined by the threshold voltage: The operation in the discharge mode is as follows.

[0096] Uth 2 , ..., Uth i , ..., Uth N Block M 2 , ..., M i , ..., M N The output voltage V s Uth 2 If it is greater than or equal to, the first cell B 1 Only the output voltage is provided.

[0097] Output voltage V s Uth 2 If the voltage of the second cell tends to drop below V s =Uth 2 , while the first cell is 100% connected (as if a switch were connecting it directly to the output with a very low voltage drop).

[0098] The first two cells are no longer at voltage Uth 2If the voltage V s Uth 2 Descend below.

[0099] If the output voltage tends to drop below Uth3, the third cell will s Uth 3 The first two cells are 100% connected, while the second cell intervenes only to the extent necessary to keep the

[0100] The last cell is V s Voltage Uth N and so on until the government intervenes to keep the

[0101] The operating principle is also illustrated in graph form in FIG.

[0102] In state "0", cell B 1 ~B i-1 is 100% connected, cell B i is the output voltage V s Voltage Uth i contributes to maintaining the other cell B i+1 ~B N will be disconnected.

[0103] V s continues to descend, and V s <Uth i If V i becomes V −ε, then cell B i is addressed and V s Uth i , at which point it changes to state "1".

[0104] In particular, the voltage V s The voltage V increases or decreases depending on whether s For comparison, a small ε may be added or subtracted from the threshold voltage to create a small hysteresis to avoid unwanted switching activity around the threshold voltage.

[0105] As above, the voltage V s >Uthi-1 If so, the highest ranked cell is cut off and B 1 , ..., B i-1 Only the 1000MHz to 1000MHz bus is connected.

[0106] In practice, the reference output voltage Uth of each regulator i , the voltage Uth that decreases with index i i With this in mind, it is easy to implement such a principle using a regulator as described in FIG. 7c.

[0107] Similarly, it is also possible to use an output voltage set point on the converter as described in FIG. 7b, a series switch mode system (described in FIG. 7a) or any other type of converter.

[0108] Note that these converters supply current to the output to maintain the output voltage at the desired set-point voltage only if the output voltage tends to drop below the set-point voltage; if the output voltage is greater than this set-point, the output current is zero (i.e. as if the cell were completely disconnected from the output).

[0109] In the recharge mode, it is possible to place all the cells in parallel or apply any other configuration via another dedicated assembly.

[0110] The linear mode can be defined by the available current: The management circuit is cell B i The maximum current I that can be supplied at any time max,i The control circuit may include or be connected to an estimator for estimating

[0111] This estimator is, for example, a function of the modification stage, temperature, etc. i The current may be based on a previous record of the maximum current that should not be exceeded in cell B. In this case, the system estimates the change state of the cells as a function of, for example, voltage, temperature, number of ampere hours elapsed, etc., and then i Determine the maximum current that can be drawn from

[0112] This maximum current I max,i The value of may further be determined to ensure a certain service life and is not an absolute maximum current but a maximum current recommended to ensure durability of the battery, a certain efficiency and / or a certain heating, etc.

[0113] In practice, this maximum current I should not be exceeded. max,i There are many possible ways to determine at all times. This is the maximum at all times, I max,i(t) It can be defined as:

[0114] The diagram of FIG. 15 shows the steps of an algorithm for managing the discharge using such operation in a linear mode defined by the available current.

[0115] In state “0”, electrical energy storage or generation cell B 1 ~B i-1 is the maximum current I max,i Supply cell B i is the voltage V s to the desired voltage V set The cells that contribute to maintaining the current state are disconnected.

[0116] In the figure, when i=1, cell B 1 Only V s V set Note that the MOSFET supplies the current necessary to maintain the

[0117] If the connected cell with the highest index supplies zero current, it may be disconnected (i=i-1). In contrast, if a contributing cell cannot maintain the output voltage, the following cell (i=i+1) must contribute.

[0118] The overall objective is to guarantee a voltage level at the output, and therefore the objective is to i is V s to the desired voltage V set "to contribute to maintaining the integrity of the - "B i is the output current Is to the desired current value I set "(Current source system)" - "B i is the current I set Within the limits of V s to the desired voltage V set "This helps maintain current-limited voltage supply systems."

[0119] current I max,i Alternatively, monitoring for output purposes may be performed using a switch mode converter as depicted in FIG. 7b, although other configurations are also contemplated, for example a step-up configuration.

[0120] Recharge (I s <0), any technique can be adopted, for example placing all the cells in parallel. One possibility is to perform the recharge by prioritizing the high index cells to recover their current capacity faster in discharge mode (if the current Is reverses sometime before the recharge is finished).

[0121] FIG. 16 shows an example of an algorithm for controlling the cells that can be used in the management circuit of an assembly according to the invention, working in reverse priority order while respecting the maximum recharging current that each cell can accept during a recharging operation.

[0122] For this purpose, each cell B i It is possible to define a recommended maximum recharging current Irechargemax,i for all times.

[0123] In FIG. 16, when i=N, the expression “B i+1 ~B N Note that "receives Irechargemax,i" is no longer valid and the cell no longer receives the maximum current. N Only the recharging current I s Receive.

[0124] In this example, the output current I sis negative because it is the recharging current and not the discharging current.

[0125] The assembly of the invention may advantageously be formed with a 3D stack such as the stack of microbatteries described in the literature, in particular in the cited document “low-power analog techniques, sensors for mobile devices, and energy efficient amplifiers”, Advances in Analog Circuit Design 2018, published by Springer, which discloses a stack of two microbatteries. For the block Mi it is possible to use a voltage regulator such as the reference MIC5225YM5-TR from Microchip. [Explanation of symbols]

[0126] B i cell CE ij Basic Cell CMi Capacitor C out load i-Rank I max,i Maximum current value I s current k Number of cells K i , K 1i , K 2i switch L Mi Inductors M i block Rg i Voltage Regulator R i resistor U high Upper Voltage Threshold U low Lower Voltage Threshold Uth i Voltage Threshold V set Desired Voltage

Claims

1. N electric energy storage or generation cells of rank i (B ｉ ), where N≧2, and each cell is a basic cell or a basic cell arranged in series and / or parallel (CE ｉｊ ) each electrical energy storage or generation cell is connected to a maximum current I ｍａｘ，ｉ N electrical energy storage or generation cells (B ｉ ), - the electrical energy storage or generation cell (B ｉ ) management circuit for managing Including, the output current I ｓ In an assembly capable of delivering The electrical energy storage or generation cells are sorted according to their rank i in decreasing usage priority, and the management circuit, in a discharge mode, selects at least one of the electrical energy storage or generation cells of rank 1, or its rank i and the following criteria: the electrical energy storage or production cell (B1) of rank 1, which generates the output current I ｓ is addressed by itself as long as it is possible to provide ｓ <I ｍａｘ１ That is, said electric energy storage or generation cell of rank 1 (B １ ) further comprises a number k of electrical energy storage or generation cells (B ｉ ) to control the current I ｓ wherein the number k is strictly greater than 2 and less than or equal to N, and satisfies the following condition: [0010] To fulfill means for addressing said electrical energy storage or generation cell according to The electrical energy storage or generation cell (B ｉ The management circuit for managing - the block of rank i (M ｉ ) Each electrical energy storage or generation cell (B ｉ ) is a block (M ｉ ), and is connected to a block (M ｉ ) ｉ ) is the output current (I ｉ ) can be delivered, The block (M ｉ ) is the output current (I ｉ ) ｓ ), and the block (M ｉ ) is the current value I ｍａｘ，１ , selects a first electrical energy storage or generation cell until it is completely depleted, and thereafter selects each next electrical energy storage or generation cell (B i ) until it is completely depleted, without exceeding a current value Imax,i.

2. Each block (M ｉ ) includes a switch, and the management circuit for managing the electrical energy storage or generation cell is configured to control the electrical energy storage or generation cell (B) through hysteresis in an all-or-nothing mode. ｉ 2. The assembly of claim 1, wherein said control means controls each of said first and second power supplies.

3. Each block (M ｉ ) is the voltage threshold Uth ｉ A regulator (Rg ｉ 2. The assembly of claim 1 , comprising:

4. The assembly includes an output voltage V ｓ Each block (M ｉ ) includes a regulator (Rg i ) operating with a voltage threshold Uth i ; Uth ２ >Uth ３ t0.5k Ｎ and - the cell of rank 1 (B １ ) is V ｓ ≧Uth ２ If it is, it is activated by itself to I ｍａｘ，１ Supplying -V ｓ <Uth ２ If so, the second cell (B ２ ) is the first cell (B １ ) to provide additional current, -V ｓ <Uth Ｎ If so, the Nth cell (B Ｎ ) is the lower-ranked cell B １ +B ２ +... B Ｎ－１ 4. The assembly of claim 3, wherein said first and second current sources are activated in addition to said first and second current sources to provide additional current.

5. Each block (M ｉ ) has a set point voltage, and - the output voltage V ｓ is lower than the set point voltage, the output voltage V ｓ providing a current at the output to maintain said set point voltage; and - providing zero current when the output voltage Vs is greater than a set point; 13. The assembly of claim 1, further comprising a switch mode converter capable of:

6. 3. An assembly according to claim 1 or 2, comprising electrical energy storage or generation cells having different capacitance values.

7. 4. The assembly of claim 3, wherein the electrical energy storage or generation cells have capacitance values ​​that decrease according to the rank i.

8. 8. An assembly according to any one of the preceding claims, wherein the management circuitry comprises means for placing all of the cells in parallel in recharge mode, corresponding to a negative output current -Is.

9. The management circuit provides a negative output current -I ｓ 8. An assembly according to claim 1, further comprising means for addressing said cells of higher rank as a priority from rank N to rank 1, corresponding to:

10. An assembly according to any one of claims 1 to 9, wherein the elementary electrical energy storage or generation cell is a battery.

11. 10. An assembly according to any one of the preceding claims, wherein the elementary electrical energy storage or generation cell is a microbattery.

12. An assembly according to any one of claims 1 to 9, wherein the primary electrical energy storage or production cell is a hydrogen fuel cell.

13. The assembly of claim 11 , wherein the microbattery and the management circuitry are included in a 3D stack.

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